// File: contracts/token/interfaces/IERC20Token.sol

pragma solidity 0.4.26;

/*
    ERC20 Standard Token interface
*/
contract IERC20Token {
    // these functions aren't abstract since the compiler emits automatically generated getter functions as external
    function name() public view returns (string) {this;}
    function symbol() public view returns (string) {this;}
    function decimals() public view returns (uint8) {this;}
    function totalSupply() public view returns (uint256) {this;}
    function balanceOf(address _owner) public view returns (uint256) {_owner; this;}
    function allowance(address _owner, address _spender) public view returns (uint256) {_owner; _spender; this;}

    function transfer(address _to, uint256 _value) public returns (bool success);
    function transferFrom(address _from, address _to, uint256 _value) public returns (bool success);
    function approve(address _spender, uint256 _value) public returns (bool success);
}

// File: contracts/IBancorNetwork.sol

pragma solidity 0.4.26;


/*
    Bancor Network interface
*/
contract IBancorNetwork {
    function convert2(
        IERC20Token[] _path,
        uint256 _amount,
        uint256 _minReturn,
        address _affiliateAccount,
        uint256 _affiliateFee
    ) public payable returns (uint256);

    function claimAndConvert2(
        IERC20Token[] _path,
        uint256 _amount,
        uint256 _minReturn,
        address _affiliateAccount,
        uint256 _affiliateFee
    ) public returns (uint256);

    function convertFor2(
        IERC20Token[] _path,
        uint256 _amount,
        uint256 _minReturn,
        address _for,
        address _affiliateAccount,
        uint256 _affiliateFee
    ) public payable returns (uint256);

    function claimAndConvertFor2(
        IERC20Token[] _path,
        uint256 _amount,
        uint256 _minReturn,
        address _for,
        address _affiliateAccount,
        uint256 _affiliateFee
    ) public returns (uint256);

    function convertForPrioritized4(
        IERC20Token[] _path,
        uint256 _amount,
        uint256 _minReturn,
        address _for,
        uint256[] memory _signature,
        address _affiliateAccount,
        uint256 _affiliateFee
    ) public payable returns (uint256);

    // deprecated, backward compatibility
    function convert(
        IERC20Token[] _path,
        uint256 _amount,
        uint256 _minReturn
    ) public payable returns (uint256);

    // deprecated, backward compatibility
    function claimAndConvert(
        IERC20Token[] _path,
        uint256 _amount,
        uint256 _minReturn
    ) public returns (uint256);

    // deprecated, backward compatibility
    function convertFor(
        IERC20Token[] _path,
        uint256 _amount,
        uint256 _minReturn,
        address _for
    ) public payable returns (uint256);

    // deprecated, backward compatibility
    function claimAndConvertFor(
        IERC20Token[] _path,
        uint256 _amount,
        uint256 _minReturn,
        address _for
    ) public returns (uint256);

    // deprecated, backward compatibility
    function convertForPrioritized3(
        IERC20Token[] _path,
        uint256 _amount,
        uint256 _minReturn,
        address _for,
        uint256 _customVal,
        uint256 _block,
        uint8 _v,
        bytes32 _r,
        bytes32 _s
    ) public payable returns (uint256);

    // deprecated, backward compatibility
    function convertForPrioritized2(
        IERC20Token[] _path,
        uint256 _amount,
        uint256 _minReturn,
        address _for,
        uint256 _block,
        uint8 _v,
        bytes32 _r,
        bytes32 _s
    ) public payable returns (uint256);

    // deprecated, backward compatibility
    function convertForPrioritized(
        IERC20Token[] _path,
        uint256 _amount,
        uint256 _minReturn,
        address _for,
        uint256 _block,
        uint256 _nonce,
        uint8 _v,
        bytes32 _r,
        bytes32 _s
    ) public payable returns (uint256);
}

// File: contracts/FeatureIds.sol

pragma solidity 0.4.26;

/**
  * @dev Id definitions for bancor contract features
  * 
  * Can be used to query the ContractFeatures contract to check whether a certain feature is supported by a contract
*/
contract FeatureIds {
    // converter features
    uint256 public constant CONVERTER_CONVERSION_WHITELIST = 1 << 0;
}

// File: contracts/utility/interfaces/IWhitelist.sol

pragma solidity 0.4.26;

/*
    Whitelist interface
*/
contract IWhitelist {
    function isWhitelisted(address _address) public view returns (bool);
}

// File: contracts/converter/interfaces/IBancorConverter.sol

pragma solidity 0.4.26;



/*
    Bancor Converter interface
*/
contract IBancorConverter {
    function getReturn(IERC20Token _fromToken, IERC20Token _toToken, uint256 _amount) public view returns (uint256, uint256);
    function convert2(IERC20Token _fromToken, IERC20Token _toToken, uint256 _amount, uint256 _minReturn, address _affiliateAccount, uint256 _affiliateFee) public returns (uint256);
    function quickConvert2(IERC20Token[] _path, uint256 _amount, uint256 _minReturn, address _affiliateAccount, uint256 _affiliateFee) public payable returns (uint256);
    function conversionWhitelist() public view returns (IWhitelist) {this;}
    function conversionFee() public view returns (uint32) {this;}
    function reserves(address _address) public view returns (uint256, uint32, bool, bool, bool) {_address; this;}
    function getReserveBalance(IERC20Token _reserveToken) public view returns (uint256);
    function reserveTokens(uint256 _index) public view returns (IERC20Token) {_index; this;}

    // deprecated, backward compatibility
    function change(IERC20Token _fromToken, IERC20Token _toToken, uint256 _amount, uint256 _minReturn) public returns (uint256);
    function convert(IERC20Token _fromToken, IERC20Token _toToken, uint256 _amount, uint256 _minReturn) public returns (uint256);
    function quickConvert(IERC20Token[] _path, uint256 _amount, uint256 _minReturn) public payable returns (uint256);
    function connectors(address _address) public view returns (uint256, uint32, bool, bool, bool);
    function getConnectorBalance(IERC20Token _connectorToken) public view returns (uint256);
    function connectorTokens(uint256 _index) public view returns (IERC20Token);
    function connectorTokenCount() public view returns (uint16);
}

// File: contracts/converter/interfaces/IBancorFormula.sol

pragma solidity 0.4.26;

/*
    Bancor Formula interface
*/
contract IBancorFormula {
    function calculatePurchaseReturn(uint256 _supply, uint256 _reserveBalance, uint32 _reserveRatio, uint256 _depositAmount) public view returns (uint256);
    function calculateSaleReturn(uint256 _supply, uint256 _reserveBalance, uint32 _reserveRatio, uint256 _sellAmount) public view returns (uint256);
    function calculateCrossReserveReturn(uint256 _fromReserveBalance, uint32 _fromReserveRatio, uint256 _toReserveBalance, uint32 _toReserveRatio, uint256 _amount) public view returns (uint256);
    function calculateFundCost(uint256 _supply, uint256 _reserveBalance, uint32 _totalRatio, uint256 _amount) public view returns (uint256);
    function calculateLiquidateReturn(uint256 _supply, uint256 _reserveBalance, uint32 _totalRatio, uint256 _amount) public view returns (uint256);
    // deprecated, backward compatibility
    function calculateCrossConnectorReturn(uint256 _fromConnectorBalance, uint32 _fromConnectorWeight, uint256 _toConnectorBalance, uint32 _toConnectorWeight, uint256 _amount) public view returns (uint256);
}

// File: contracts/converter/interfaces/IBancorGasPriceLimit.sol

pragma solidity 0.4.26;

/*
    Bancor Gas Price Limit interface
*/
contract IBancorGasPriceLimit {
    function gasPrice() public view returns (uint256) {this;}
    function validateGasPrice(uint256) public view;
}

// File: contracts/utility/interfaces/IOwned.sol

pragma solidity 0.4.26;

/*
    Owned contract interface
*/
contract IOwned {
    // this function isn't abstract since the compiler emits automatically generated getter functions as external
    function owner() public view returns (address) {this;}

    function transferOwnership(address _newOwner) public;
    function acceptOwnership() public;
}

// File: contracts/utility/Owned.sol

pragma solidity 0.4.26;


/**
  * @dev Provides support and utilities for contract ownership
*/
contract Owned is IOwned {
    address public owner;
    address public newOwner;

    /**
      * @dev triggered when the owner is updated
      * 
      * @param _prevOwner previous owner
      * @param _newOwner  new owner
    */
    event OwnerUpdate(address indexed _prevOwner, address indexed _newOwner);

    /**
      * @dev initializes a new Owned instance
    */
    constructor() public {
        owner = msg.sender;
    }

    // allows execution by the owner only
    modifier ownerOnly {
        require(msg.sender == owner);
        _;
    }

    /**
      * @dev allows transferring the contract ownership
      * the new owner still needs to accept the transfer
      * can only be called by the contract owner
      * 
      * @param _newOwner    new contract owner
    */
    function transferOwnership(address _newOwner) public ownerOnly {
        require(_newOwner != owner);
        newOwner = _newOwner;
    }

    /**
      * @dev used by a new owner to accept an ownership transfer
    */
    function acceptOwnership() public {
        require(msg.sender == newOwner);
        emit OwnerUpdate(owner, newOwner);
        owner = newOwner;
        newOwner = address(0);
    }
}

// File: contracts/utility/Utils.sol

pragma solidity 0.4.26;

/**
  * @dev Utilities & Common Modifiers
*/
contract Utils {
    /**
      * constructor
    */
    constructor() public {
    }

    // verifies that an amount is greater than zero
    modifier greaterThanZero(uint256 _amount) {
        require(_amount > 0);
        _;
    }

    // validates an address - currently only checks that it isn't null
    modifier validAddress(address _address) {
        require(_address != address(0));
        _;
    }

    // verifies that the address is different than this contract address
    modifier notThis(address _address) {
        require(_address != address(this));
        _;
    }

}

// File: contracts/utility/interfaces/ITokenHolder.sol

pragma solidity 0.4.26;



/*
    Token Holder interface
*/
contract ITokenHolder is IOwned {
    function withdrawTokens(IERC20Token _token, address _to, uint256 _amount) public;
}

// File: contracts/token/interfaces/INonStandardERC20.sol

pragma solidity 0.4.26;

/*
    ERC20 Standard Token interface which doesn't return true/false for transfer, transferFrom and approve
*/
contract INonStandardERC20 {
    // these functions aren't abstract since the compiler emits automatically generated getter functions as external
    function name() public view returns (string) {this;}
    function symbol() public view returns (string) {this;}
    function decimals() public view returns (uint8) {this;}
    function totalSupply() public view returns (uint256) {this;}
    function balanceOf(address _owner) public view returns (uint256) {_owner; this;}
    function allowance(address _owner, address _spender) public view returns (uint256) {_owner; _spender; this;}

    function transfer(address _to, uint256 _value) public;
    function transferFrom(address _from, address _to, uint256 _value) public;
    function approve(address _spender, uint256 _value) public;
}

// File: contracts/utility/TokenHolder.sol

pragma solidity 0.4.26;






/**
  * @dev We consider every contract to be a 'token holder' since it's currently not possible
  * for a contract to deny receiving tokens.
  * 
  * The TokenHolder's contract sole purpose is to provide a safety mechanism that allows
  * the owner to send tokens that were sent to the contract by mistake back to their sender.
  * 
  * Note that we use the non standard ERC-20 interface which has no return value for transfer
  * in order to support both non standard as well as standard token contracts.
  * see https://github.com/ethereum/solidity/issues/4116
*/
contract TokenHolder is ITokenHolder, Owned, Utils {
    /**
      * @dev initializes a new TokenHolder instance
    */
    constructor() public {
    }

    /**
      * @dev withdraws tokens held by the contract and sends them to an account
      * can only be called by the owner
      * 
      * @param _token   ERC20 token contract address
      * @param _to      account to receive the new amount
      * @param _amount  amount to withdraw
    */
    function withdrawTokens(IERC20Token _token, address _to, uint256 _amount)
        public
        ownerOnly
        validAddress(_token)
        validAddress(_to)
        notThis(_to)
    {
        INonStandardERC20(_token).transfer(_to, _amount);
    }
}

// File: contracts/utility/SafeMath.sol

pragma solidity 0.4.26;

/**
  * @dev Library for basic math operations with overflow/underflow protection
*/
library SafeMath {
    /**
      * @dev returns the sum of _x and _y, reverts if the calculation overflows
      * 
      * @param _x   value 1
      * @param _y   value 2
      * 
      * @return sum
    */
    function add(uint256 _x, uint256 _y) internal pure returns (uint256) {
        uint256 z = _x + _y;
        require(z >= _x);
        return z;
    }

    /**
      * @dev returns the difference of _x minus _y, reverts if the calculation underflows
      * 
      * @param _x   minuend
      * @param _y   subtrahend
      * 
      * @return difference
    */
    function sub(uint256 _x, uint256 _y) internal pure returns (uint256) {
        require(_x >= _y);
        return _x - _y;
    }

    /**
      * @dev returns the product of multiplying _x by _y, reverts if the calculation overflows
      * 
      * @param _x   factor 1
      * @param _y   factor 2
      * 
      * @return product
    */
    function mul(uint256 _x, uint256 _y) internal pure returns (uint256) {
        // gas optimization
        if (_x == 0)
            return 0;

        uint256 z = _x * _y;
        require(z / _x == _y);
        return z;
    }

      /**
        * ev Integer division of two numbers truncating the quotient, reverts on division by zero.
        * 
        * aram _x   dividend
        * aram _y   divisor
        * 
        * eturn quotient
    */
    function div(uint256 _x, uint256 _y) internal pure returns (uint256) {
        require(_y > 0);
        uint256 c = _x / _y;

        return c;
    }
}

// File: contracts/utility/interfaces/IContractRegistry.sol

pragma solidity 0.4.26;

/*
    Contract Registry interface
*/
contract IContractRegistry {
    function addressOf(bytes32 _contractName) public view returns (address);

    // deprecated, backward compatibility
    function getAddress(bytes32 _contractName) public view returns (address);
}

// File: contracts/utility/ContractRegistryClient.sol

pragma solidity 0.4.26;




/**
  * @dev Base contract for ContractRegistry clients
*/
contract ContractRegistryClient is Owned, Utils {
    bytes32 internal constant CONTRACT_FEATURES = "ContractFeatures";
    bytes32 internal constant CONTRACT_REGISTRY = "ContractRegistry";
    bytes32 internal constant BANCOR_NETWORK = "BancorNetwork";
    bytes32 internal constant BANCOR_FORMULA = "BancorFormula";
    bytes32 internal constant BANCOR_GAS_PRICE_LIMIT = "BancorGasPriceLimit";
    bytes32 internal constant BANCOR_CONVERTER_FACTORY = "BancorConverterFactory";
    bytes32 internal constant BANCOR_CONVERTER_UPGRADER = "BancorConverterUpgrader";
    bytes32 internal constant BANCOR_CONVERTER_REGISTRY = "BancorConverterRegistry";
    bytes32 internal constant BANCOR_CONVERTER_REGISTRY_DATA = "BancorConverterRegistryData";
    bytes32 internal constant BNT_TOKEN = "BNTToken";
    bytes32 internal constant BANCOR_X = "BancorX";
    bytes32 internal constant BANCOR_X_UPGRADER = "BancorXUpgrader";

    IContractRegistry public registry;      // address of the current contract-registry
    IContractRegistry public prevRegistry;  // address of the previous contract-registry
    bool public adminOnly;                  // only an administrator can update the contract-registry

    /**
      * @dev verifies that the caller is mapped to the given contract name
      * 
      * @param _contractName    contract name
    */
    modifier only(bytes32 _contractName) {
        require(msg.sender == addressOf(_contractName));
        _;
    }

    /**
      * @dev initializes a new ContractRegistryClient instance
      * 
      * @param  _registry   address of a contract-registry contract
    */
    constructor(IContractRegistry _registry) internal validAddress(_registry) {
        registry = IContractRegistry(_registry);
        prevRegistry = IContractRegistry(_registry);
    }

    /**
      * @dev updates to the new contract-registry
     */
    function updateRegistry() public {
        // verify that this function is permitted
        require(!adminOnly || isAdmin());

        // get the new contract-registry
        address newRegistry = addressOf(CONTRACT_REGISTRY);

        // verify that the new contract-registry is different and not zero
        require(newRegistry != address(registry) && newRegistry != address(0));

        // verify that the new contract-registry is pointing to a non-zero contract-registry
        require(IContractRegistry(newRegistry).addressOf(CONTRACT_REGISTRY) != address(0));

        // save a backup of the current contract-registry before replacing it
        prevRegistry = registry;

        // replace the current contract-registry with the new contract-registry
        registry = IContractRegistry(newRegistry);
    }

    /**
      * @dev restores the previous contract-registry
    */
    function restoreRegistry() public {
        // verify that this function is permitted
        require(isAdmin());

        // restore the previous contract-registry
        registry = prevRegistry;
    }

    /**
      * @dev restricts the permission to update the contract-registry
      * 
      * @param _adminOnly    indicates whether or not permission is restricted to administrator only
    */
    function restrictRegistryUpdate(bool _adminOnly) public {
        // verify that this function is permitted
        require(adminOnly != _adminOnly && isAdmin());

        // change the permission to update the contract-registry
        adminOnly = _adminOnly;
    }

    /**
      * @dev returns whether or not the caller is an administrator
     */
    function isAdmin() internal view returns (bool) {
        return msg.sender == owner;
    }

    /**
      * @dev returns the address associated with the given contract name
      * 
      * @param _contractName    contract name
      * 
      * @return contract address
    */
    function addressOf(bytes32 _contractName) internal view returns (address) {
        return registry.addressOf(_contractName);
    }
}

// File: contracts/utility/interfaces/IContractFeatures.sol

pragma solidity 0.4.26;

/*
    Contract Features interface
*/
contract IContractFeatures {
    function isSupported(address _contract, uint256 _features) public view returns (bool);
    function enableFeatures(uint256 _features, bool _enable) public;
}

// File: contracts/utility/interfaces/IAddressList.sol

pragma solidity 0.4.26;

/*
    Address list interface
*/
contract IAddressList {
    mapping (address => bool) public listedAddresses;
}

// File: contracts/token/interfaces/IEtherToken.sol

pragma solidity 0.4.26;



/*
    Ether Token interface
*/
contract IEtherToken is ITokenHolder, IERC20Token {
    function deposit() public payable;
    function withdraw(uint256 _amount) public;
    function withdrawTo(address _to, uint256 _amount) public;
}

// File: contracts/token/interfaces/ISmartToken.sol

pragma solidity 0.4.26;



/*
    Smart Token interface
*/
contract ISmartToken is IOwned, IERC20Token {
    function disableTransfers(bool _disable) public;
    function issue(address _to, uint256 _amount) public;
    function destroy(address _from, uint256 _amount) public;
}

// File: contracts/bancorx/interfaces/IBancorX.sol

pragma solidity 0.4.26;

contract IBancorX {
    function xTransfer(bytes32 _toBlockchain, bytes32 _to, uint256 _amount, uint256 _id) public;
    function getXTransferAmount(uint256 _xTransferId, address _for) public view returns (uint256);
}

// File: contracts/BancorNetwork.sol

pragma solidity 0.4.26;
















/**
  * @dev The BancorNetwork contract is the main entry point for Bancor token conversions.
  * It also allows for the conversion of any token in the Bancor Network to any other token in a single transaction by providing a conversion path.
  * 
  * A note on Conversion Path: Conversion path is a data structure that is used when converting a token to another token in the Bancor Network,
  * when the conversion cannot necessarily be done by a single converter and might require multiple 'hops'.
  * The path defines which converters should be used and what kind of conversion should be done in each step.
  * 
  * The path format doesn't include complex structure; instead, it is represented by a single array in which each 'hop' is represented by a 2-tuple - smart token & to token.
  * In addition, the first element is always the source token.
  * The smart token is only used as a pointer to a converter (since converter addresses are more likely to change as opposed to smart token addresses).
  * 
  * Format:
  * [source token, smart token, to token, smart token, to token...]
*/
contract BancorNetwork is IBancorNetwork, TokenHolder, ContractRegistryClient, FeatureIds {
    using SafeMath for uint256;

    uint256 private constant CONVERSION_FEE_RESOLUTION = 1000000;
    uint256 private constant AFFILIATE_FEE_RESOLUTION = 1000000;

    uint256 public maxAffiliateFee = 30000;     // maximum affiliate-fee
    address public signerAddress = 0x0;         // verified address that allows conversions with higher gas price

    mapping (address => bool) public etherTokens;       // list of all supported ether tokens
    mapping (bytes32 => bool) public conversionHashes;  // list of conversion hashes, to prevent re-use of the same hash

    /**
      * @dev triggered when a conversion between two tokens occurs
      * 
      * @param _smartToken      smart token governed by the converter
      * @param _fromToken       ERC20 token converted from
      * @param _toToken         ERC20 token converted to
      * @param _fromAmount      amount converted, in fromToken
      * @param _toAmount        amount returned, minus conversion fee
      * @param _trader          wallet that initiated the trade
    */
    event Conversion(
        address indexed _smartToken,
        address indexed _fromToken,
        address indexed _toToken,
        uint256 _fromAmount,
        uint256 _toAmount,
        address _trader
    );

    /**
      * @dev initializes a new BancorNetwork instance
      * 
      * @param _registry    address of a contract registry contract
    */
    constructor(IContractRegistry _registry) ContractRegistryClient(_registry) public {
    }

    /**
      * @dev allows the owner to update the maximum affiliate-fee
      * 
      * @param _maxAffiliateFee   maximum affiliate-fee
    */
    function setMaxAffiliateFee(uint256 _maxAffiliateFee)
        public
        ownerOnly
    {
        require(_maxAffiliateFee <= AFFILIATE_FEE_RESOLUTION);
        maxAffiliateFee = _maxAffiliateFee;
    }

    /**
      * @dev allows the owner to update the signer address
      * 
      * @param _signerAddress    new signer address
    */
    function setSignerAddress(address _signerAddress)
        public
        ownerOnly
        validAddress(_signerAddress)
        notThis(_signerAddress)
    {
        signerAddress = _signerAddress;
    }

    /**
      * @dev allows the owner to register/unregister ether tokens
      * 
      * @param _token       ether token contract address
      * @param _register    true to register, false to unregister
    */
    function registerEtherToken(IEtherToken _token, bool _register)
        public
        ownerOnly
        validAddress(_token)
        notThis(_token)
    {
        etherTokens[_token] = _register;
    }

    /**
      * @dev verifies that the signer address is the one associated with the public key from a given elliptic curve signature
      * note that the signature is valid only for one conversion, and that it expires after the give block
    */
    function verifyTrustedSender(IERC20Token[] _path, address _addr, uint256[] memory _signature) private {
        uint256 blockNumber = _signature[1];

        // check that the current block number doesn't exceeded the maximum allowed with the current signature
        require(block.number <= blockNumber);

        // create the hash of the given signature
        bytes32 hash = keccak256(abi.encodePacked(blockNumber, tx.gasprice, _addr, msg.sender, _signature[0], _path));

        // check that it is the first conversion with the given signature
        require(!conversionHashes[hash]);

        // verify that the signing address is identical to the trusted signer address in the contract
        bytes32 prefixedHash = keccak256(abi.encodePacked("\x19Ethereum Signed Message:\n32", hash));
        require(ecrecover(prefixedHash, uint8(_signature[2]), bytes32(_signature[3]), bytes32(_signature[4])) == signerAddress);

        // mark the hash so that it can't be used multiple times
        conversionHashes[hash] = true;
    }

    /**
      * @dev converts the token to any other token in the bancor network by following
      * a predefined conversion path and transfers the result tokens to a target account
      * note that the network should already own the source tokens
      * 
      * @param _path                conversion path, see conversion path format above
      * @param _amount              amount to convert from (in the initial source token)
      * @param _minReturn           if the conversion results in an amount smaller than the minimum return - it is cancelled, must be nonzero
      * @param _for                 account that will receive the conversion result
      * @param _affiliateAccount    affiliate account
      * @param _affiliateFee        affiliate fee in PPM
      * 
      * @return tokens issued in return
    */
    function convertFor2(IERC20Token[] _path, uint256 _amount, uint256 _minReturn, address _for, address _affiliateAccount, uint256 _affiliateFee) public payable returns (uint256) {
        return convertForPrioritized4(_path, _amount, _minReturn, _for, getSignature(0x0, 0x0, 0x0, 0x0, 0x0), _affiliateAccount, _affiliateFee);
    }

    /**
      * @dev converts the token to any other token in the bancor network
      * by following a predefined conversion path and transfers the result
      * tokens to a target account.
      * this version of the function also allows the verified signer
      * to bypass the universal gas price limit.
      * note that the network should already own the source tokens
      * 
      * @param _path                conversion path, see conversion path format above
      * @param _amount              amount to convert from (in the initial source token)
      * @param _minReturn           if the conversion results in an amount smaller than the minimum return - it is cancelled, must be nonzero
      * @param _for                 account that will receive the conversion result
      * @param _signature           an array of the following elements:
      *     [0] uint256             custom value that was signed for prioritized conversion
      *     [1] uint256             if the current block exceeded the given parameter - it is cancelled
      *     [2] uint8               (signature[128:130]) associated with the signer address and helps to validate if the signature is legit
      *     [3] bytes32             (signature[0:64]) associated with the signer address and helps to validate if the signature is legit
      *     [4] bytes32             (signature[64:128]) associated with the signer address and helps to validate if the signature is legit
      * if the array is empty (length == 0), then the gas-price limit is verified instead of the signature
      * @param _affiliateAccount    affiliate account
      * @param _affiliateFee        affiliate fee in PPM
      * 
      * @return tokens issued in return
    */
    function convertForPrioritized4(
        IERC20Token[] _path,
        uint256 _amount,
        uint256 _minReturn,
        address _for,
        uint256[] memory _signature,
        address _affiliateAccount,
        uint256 _affiliateFee
    )
        public
        payable
        returns (uint256)
    {
        // verify that the conversion parameters are legal
        verifyConversionParams(_path, _for, _for, _signature);

        // handle msg.value
        handleValue(_path[0], _amount, false);

        // convert and get the resulting amount
        uint256 amount = convertByPath(_path, _amount, _minReturn, _affiliateAccount, _affiliateFee);

        // finished the conversion, transfer the funds to the target account
        // if the target token is an ether token, withdraw the tokens and send them as ETH
        // otherwise, transfer the tokens as is
        IERC20Token toToken = _path[_path.length - 1];
        if (etherTokens[toToken])
            IEtherToken(toToken).withdrawTo(_for, amount);
        else
            ensureTransferFrom(toToken, this, _for, amount);

        return amount;
    }

    /**
      * @dev converts any other token to BNT in the bancor network
      * by following a predefined conversion path and transfers the resulting
      * tokens to BancorX.
      * note that the network should already have been given allowance of the source token (if not ETH)
      * 
      * @param _path                conversion path, see conversion path format above
      * @param _amount              amount to convert from (in the initial source token)
      * @param _minReturn           if the conversion results in an amount smaller than the minimum return - it is cancelled, must be nonzero
      * @param _toBlockchain        blockchain BNT will be issued on
      * @param _to                  address/account on _toBlockchain to send the BNT to
      * @param _conversionId        pre-determined unique (if non zero) id which refers to this transaction 
      * @param _affiliateAccount    affiliate account
      * @param _affiliateFee        affiliate fee in PPM
      * 
      * @return the amount of BNT received from this conversion
    */
    function xConvert2(
        IERC20Token[] _path,
        uint256 _amount,
        uint256 _minReturn,
        bytes32 _toBlockchain,
        bytes32 _to,
        uint256 _conversionId,
        address _affiliateAccount,
        uint256 _affiliateFee
    )
        public
        payable
        returns (uint256)
    {
        return xConvertPrioritized3(_path, _amount, _minReturn, _toBlockchain, _to, _conversionId, getSignature(0x0, 0x0, 0x0, 0x0, 0x0), _affiliateAccount, _affiliateFee);
    }

    /**
      * @dev converts any other token to BNT in the bancor network
      * by following a predefined conversion path and transfers the resulting
      * tokens to BancorX.
      * this version of the function also allows the verified signer
      * to bypass the universal gas price limit.
      * note that the network should already have been given allowance of the source token (if not ETH)
      * 
      * @param _path                conversion path, see conversion path format above
      * @param _amount              amount to convert from (in the initial source token)
      * @param _minReturn           if the conversion results in an amount smaller than the minimum return - it is cancelled, must be nonzero
      * @param _toBlockchain        blockchain BNT will be issued on
      * @param _to                  address/account on _toBlockchain to send the BNT to
      * @param _conversionId        pre-determined unique (if non zero) id which refers to this transaction 
      * @param _signature           an array of the following elements:
      *     [0] uint256             custom value that was signed for prioritized conversion; must be equal to _amount
      *     [1] uint256             if the current block exceeded the given parameter - it is cancelled
      *     [2] uint8               (signature[128:130]) associated with the signer address and helps to validate if the signature is legit
      *     [3] bytes32             (signature[0:64]) associated with the signer address and helps to validate if the signature is legit
      *     [4] bytes32             (signature[64:128]) associated with the signer address and helps to validate if the signature is legit
      * if the array is empty (length == 0), then the gas-price limit is verified instead of the signature
      * @param _affiliateAccount    affiliate account
      * @param _affiliateFee        affiliate fee in PPM
      * 
      * @return the amount of BNT received from this conversion
    */
    function xConvertPrioritized3(
        IERC20Token[] _path,
        uint256 _amount,
        uint256 _minReturn,
        bytes32 _toBlockchain,
        bytes32 _to,
        uint256 _conversionId,
        uint256[] memory _signature,
        address _affiliateAccount,
        uint256 _affiliateFee
    )
        public
        payable
        returns (uint256)
    {
        // verify that the custom value (if valid) is equal to _amount
        require(_signature.length == 0 || _signature[0] == _amount);

        // verify that the conversion parameters are legal
        verifyConversionParams(_path, msg.sender, this, _signature);

        // verify that the destination token is BNT
        require(_path[_path.length - 1] == addressOf(BNT_TOKEN));

        // handle msg.value
        handleValue(_path[0], _amount, true);

        // convert and get the resulting amount
        uint256 amount = convertByPath(_path, _amount, _minReturn, _affiliateAccount, _affiliateFee);

        // transfer the resulting amount to BancorX
        IBancorX(addressOf(BANCOR_X)).xTransfer(_toBlockchain, _to, amount, _conversionId);

        return amount;
    }

    /**
      * @dev executes the actual conversion by following the conversion path
      * 
      * @param _path                conversion path, see conversion path format above
      * @param _amount              amount to convert from (in the initial source token)
      * @param _minReturn           if the conversion results in an amount smaller than the minimum return - it is cancelled, must be nonzero
      * @param _affiliateAccount    affiliate account
      * @param _affiliateFee        affiliate fee in PPM
      * 
      * @return amount of tokens issued
    */
    function convertByPath(
        IERC20Token[] _path,
        uint256 _amount,
        uint256 _minReturn,
        address _affiliateAccount,
        uint256 _affiliateFee
    ) private returns (uint256) {
        uint256 toAmount;
        uint256 fromAmount = _amount;
        uint256 lastIndex = _path.length - 1;

        address bntToken;
        if (address(_affiliateAccount) == 0) {
            require(_affiliateFee == 0);
            bntToken = address(0);
        }
        else {
            require(0 < _affiliateFee && _affiliateFee <= maxAffiliateFee);
            bntToken = addressOf(BNT_TOKEN);
        }

        // iterate over the conversion path
        for (uint256 i = 2; i <= lastIndex; i += 2) {
            IBancorConverter converter = IBancorConverter(ISmartToken(_path[i - 1]).owner());

            // if the smart token isn't the source (from token), the converter doesn't have control over it and thus we need to approve the request
            if (_path[i - 1] != _path[i - 2])
                ensureAllowance(_path[i - 2], converter, fromAmount);

            // make the conversion - if it's the last one, also provide the minimum return value
            toAmount = converter.change(_path[i - 2], _path[i], fromAmount, i == lastIndex ? _minReturn : 1);

            // pay affiliate-fee if needed
            if (address(_path[i]) == bntToken) {
                uint256 affiliateAmount = toAmount.mul(_affiliateFee).div(AFFILIATE_FEE_RESOLUTION);
                require(_path[i].transfer(_affiliateAccount, affiliateAmount));
                toAmount -= affiliateAmount;
                bntToken = address(0);
            }

            emit Conversion(_path[i - 1], _path[i - 2], _path[i], fromAmount, toAmount, msg.sender);
            fromAmount = toAmount;
        }

        return toAmount;
    }

    bytes4 private constant GET_RETURN_FUNC_SELECTOR = bytes4(uint256(keccak256("getReturn(address,address,uint256)") >> (256 - 4 * 8)));

    function getReturn(address _dest, address _fromToken, address _toToken, uint256 _amount) internal view returns (uint256, uint256) {
        uint256[2] memory ret;
        bytes memory data = abi.encodeWithSelector(GET_RETURN_FUNC_SELECTOR, _fromToken, _toToken, _amount);

        assembly {
            let success := staticcall(
                gas,           // gas remaining
                _dest,         // destination address
                add(data, 32), // input buffer (starts after the first 32 bytes in the `data` array)
                mload(data),   // input length (loaded from the first 32 bytes in the `data` array)
                ret,           // output buffer
                64             // output length
            )
            if iszero(success) {
                revert(0, 0)
            }
        }

        return (ret[0], ret[1]);
    }

    /**
      * @dev calculates the expected return of converting a given amount on a given path
      * note that there is no support for circular paths
      * 
      * @param _path        conversion path (see conversion path format above)
      * @param _amount      amount of _path[0] tokens received from the user
      * 
      * @return amount of _path[_path.length - 1] tokens that the user will receive
      * @return amount of _path[_path.length - 1] tokens that the user will pay as fee
    */
    function getReturnByPath(IERC20Token[] _path, uint256 _amount) public view returns (uint256, uint256) {
        uint256 amount;
        uint256 fee;
        uint256 supply;
        uint256 balance;
        uint32 ratio;
        IBancorConverter converter;
        IBancorFormula formula = IBancorFormula(addressOf(BANCOR_FORMULA));

        amount = _amount;

        // verify that the number of elements is larger than 2 and odd
        require(_path.length > 2 && _path.length % 2 == 1);

        // iterate over the conversion path
        for (uint256 i = 2; i < _path.length; i += 2) {
            IERC20Token fromToken = _path[i - 2];
            IERC20Token smartToken = _path[i - 1];
            IERC20Token toToken = _path[i];

            if (toToken == smartToken) { // buy the smart token
                // check if the current smart token has changed
                if (i < 3 || smartToken != _path[i - 3]) {
                    supply = smartToken.totalSupply();
                    converter = IBancorConverter(ISmartToken(smartToken).owner());
                }

                // calculate the amount & the conversion fee
                balance = converter.getConnectorBalance(fromToken);
                (, ratio, , , ) = converter.connectors(fromToken);
                amount = formula.calculatePurchaseReturn(supply, balance, ratio, amount);
                fee = amount.mul(converter.conversionFee()).div(CONVERSION_FEE_RESOLUTION);
                amount -= fee;

                // update the smart token supply for the next iteration
                supply += amount;
            }
            else if (fromToken == smartToken) { // sell the smart token
                // check if the current smart token has changed
                if (i < 3 || smartToken != _path[i - 3]) {
                    supply = smartToken.totalSupply();
                    converter = IBancorConverter(ISmartToken(smartToken).owner());
                }

                // calculate the amount & the conversion fee
                balance = converter.getConnectorBalance(toToken);
                (, ratio, , , ) = converter.connectors(toToken);
                amount = formula.calculateSaleReturn(supply, balance, ratio, amount);
                fee = amount.mul(converter.conversionFee()).div(CONVERSION_FEE_RESOLUTION);
                amount -= fee;

                // update the smart token supply for the next iteration
                supply -= amount;
            }
            else { // cross reserve conversion
                // check if the current smart token has changed
                if (i < 3 || smartToken != _path[i - 3]) {
                    converter = IBancorConverter(ISmartToken(smartToken).owner());
                }

                (amount, fee) = getReturn(converter, fromToken, toToken, amount);
            }
        }

        return (amount, fee);
    }

    /**
      * @dev claims the caller's tokens, converts them to any other token in the bancor network
      * by following a predefined conversion path and transfers the result tokens to a target account
      * note that allowance must be set beforehand
      * 
      * @param _path                conversion path, see conversion path format above
      * @param _amount              amount to convert from (in the initial source token)
      * @param _minReturn           if the conversion results in an amount smaller than the minimum return - it is cancelled, must be nonzero
      * @param _for                 account that will receive the conversion result
      * @param _affiliateAccount    affiliate account
      * @param _affiliateFee        affiliate fee in PPM
      * 
      * @return tokens issued in return
    */
    function claimAndConvertFor2(IERC20Token[] _path, uint256 _amount, uint256 _minReturn, address _for, address _affiliateAccount, uint256 _affiliateFee) public returns (uint256) {
        // we need to transfer the tokens from the caller to the network before we follow
        // the conversion path, to allow it to execute the conversion on behalf of the caller
        // note: we assume we already have allowance
        IERC20Token fromToken = _path[0];
        ensureTransferFrom(fromToken, msg.sender, this, _amount);
        return convertFor2(_path, _amount, _minReturn, _for, _affiliateAccount, _affiliateFee);
    }

    /**
      * @dev converts the token to any other token in the bancor network by following
      * a predefined conversion path and transfers the result tokens back to the sender
      * note that the network should already own the source tokens
      * 
      * @param _path                conversion path, see conversion path format above
      * @param _amount              amount to convert from (in the initial source token)
      * @param _minReturn           if the conversion results in an amount smaller than the minimum return - it is cancelled, must be nonzero
      * @param _affiliateAccount    affiliate account
      * @param _affiliateFee        affiliate fee in PPM
      * 
      * @return tokens issued in return
    */
    function convert2(IERC20Token[] _path, uint256 _amount, uint256 _minReturn, address _affiliateAccount, uint256 _affiliateFee) public payable returns (uint256) {
        return convertFor2(_path, _amount, _minReturn, msg.sender, _affiliateAccount, _affiliateFee);
    }

    /**
      * @dev claims the caller's tokens, converts them to any other token in the bancor network
      * by following a predefined conversion path and transfers the result tokens back to the sender
      * note that allowance must be set beforehand
      * 
      * @param _path                conversion path, see conversion path format above
      * @param _amount              amount to convert from (in the initial source token)
      * @param _minReturn           if the conversion results in an amount smaller than the minimum return - it is cancelled, must be nonzero
      * @param _affiliateAccount    affiliate account
      * @param _affiliateFee        affiliate fee in PPM
      * 
      * @return tokens issued in return
    */
    function claimAndConvert2(IERC20Token[] _path, uint256 _amount, uint256 _minReturn, address _affiliateAccount, uint256 _affiliateFee) public returns (uint256) {
        return claimAndConvertFor2(_path, _amount, _minReturn, msg.sender, _affiliateAccount, _affiliateFee);
    }

    /**
      * @dev ensures transfer of tokens, taking into account that some ERC-20 implementations don't return
      * true on success but revert on failure instead
      * 
      * @param _token     the token to transfer
      * @param _from      the address to transfer the tokens from
      * @param _to        the address to transfer the tokens to
      * @param _amount    the amount to transfer
    */
    function ensureTransferFrom(IERC20Token _token, address _from, address _to, uint256 _amount) private {
        // We must assume that functions `transfer` and `transferFrom` do not return anything,
        // because not all tokens abide the requirement of the ERC20 standard to return success or failure.
        // This is because in the current compiler version, the calling contract can handle more returned data than expected but not less.
        // This may change in the future, so that the calling contract will revert if the size of the data is not exactly what it expects.
        uint256 prevBalance = _token.balanceOf(_to);
        if (_from == address(this))
            INonStandardERC20(_token).transfer(_to, _amount);
        else
            INonStandardERC20(_token).transferFrom(_from, _to, _amount);
        uint256 postBalance = _token.balanceOf(_to);
        require(postBalance > prevBalance);
    }

    /**
      * @dev utility, checks whether allowance for the given spender exists and approves one if it doesn't.
      * Note that we use the non standard erc-20 interface in which `approve` has no return value so that
      * this function will work for both standard and non standard tokens
      * 
      * @param _token   token to check the allowance in
      * @param _spender approved address
      * @param _value   allowance amount
    */
    function ensureAllowance(IERC20Token _token, address _spender, uint256 _value) private {
        uint256 allowance = _token.allowance(this, _spender);
        if (allowance < _value) {
            if (allowance > 0)
                INonStandardERC20(_token).approve(_spender, 0);
            INonStandardERC20(_token).approve(_spender, _value);
        }
    }

    function getSignature(
        uint256 _customVal,
        uint256 _block,
        uint8 _v,
        bytes32 _r,
        bytes32 _s
    ) private pure returns (uint256[] memory) {
        if (_v == 0x0 && _r == 0x0 && _s == 0x0)
            return new uint256[](0);
        uint256[] memory signature = new uint256[](5);
        signature[0] = _customVal;
        signature[1] = _block;
        signature[2] = uint256(_v);
        signature[3] = uint256(_r);
        signature[4] = uint256(_s);
        return signature;
    }

    function verifyConversionParams(
        IERC20Token[] _path,
        address _sender,
        address _receiver,
        uint256[] memory _signature
    )
        private
    {
        // verify that the number of elements is odd and that maximum number of 'hops' is 10
        require(_path.length > 2 && _path.length <= (1 + 2 * 10) && _path.length % 2 == 1);

        // verify that the account which should receive the conversion result is whitelisted
        IContractFeatures features = IContractFeatures(addressOf(CONTRACT_FEATURES));
        for (uint256 i = 1; i < _path.length; i += 2) {
            IBancorConverter converter = IBancorConverter(ISmartToken(_path[i]).owner());
            if (features.isSupported(converter, FeatureIds.CONVERTER_CONVERSION_WHITELIST)) {
                IWhitelist whitelist = converter.conversionWhitelist();
                require(whitelist == address(0) || whitelist.isWhitelisted(_receiver));
            }
        }

        if (_signature.length >= 5) {
            // verify signature
            verifyTrustedSender(_path, _sender, _signature);
        }
        else {
            // verify gas price limit
            IBancorGasPriceLimit gasPriceLimit = IBancorGasPriceLimit(addressOf(BANCOR_GAS_PRICE_LIMIT));
            gasPriceLimit.validateGasPrice(tx.gasprice);
        }
    }

    function handleValue(IERC20Token _token, uint256 _amount, bool _claim) private {
        // if ETH is provided, ensure that the amount is identical to _amount, verify that the source token is an ether token and deposit the ETH in it
        if (msg.value > 0) {
            require(_amount == msg.value && etherTokens[_token]);
            IEtherToken(_token).deposit.value(msg.value)();
        }
        // Otherwise, claim the tokens from the sender if needed
        else if (_claim) {
            ensureTransferFrom(_token, msg.sender, this, _amount);
        }
    }

    /**
      * @dev deprecated, backward compatibility
    */
    function convert(
        IERC20Token[] _path,
        uint256 _amount,
        uint256 _minReturn
    ) public payable returns (uint256)
    {
        return convert2(_path, _amount, _minReturn, address(0), 0);
    }

    /**
      * @dev deprecated, backward compatibility
    */
    function claimAndConvert(
        IERC20Token[] _path,
        uint256 _amount,
        uint256 _minReturn
    ) public returns (uint256)
    {
        return claimAndConvert2(_path, _amount, _minReturn, address(0), 0);
    }

    /**
      * @dev deprecated, backward compatibility
    */
    function convertFor(
        IERC20Token[] _path,
        uint256 _amount,
        uint256 _minReturn,
        address _for
    ) public payable returns (uint256)
    {
        return convertFor2(_path, _amount, _minReturn, _for, address(0), 0);
    }

    /**
      * @dev deprecated, backward compatibility
    */
    function claimAndConvertFor(
        IERC20Token[] _path,
        uint256 _amount,
        uint256 _minReturn,
        address _for
    ) public returns (uint256)
    {
        return claimAndConvertFor2(_path, _amount, _minReturn, _for, address(0), 0);
    }

    /**
      * @dev deprecated, backward compatibility
    */
    function xConvert(
        IERC20Token[] _path,
        uint256 _amount,
        uint256 _minReturn,
        bytes32 _toBlockchain,
        bytes32 _to,
        uint256 _conversionId
    )
        public
        payable
        returns (uint256)
    {
        return xConvert2(_path, _amount, _minReturn, _toBlockchain, _to, _conversionId, address(0), 0);
    }

    /**
      * @dev deprecated, backward compatibility
    */
    function xConvertPrioritized2(
        IERC20Token[] _path,
        uint256 _amount,
        uint256 _minReturn,
        bytes32 _toBlockchain,
        bytes32 _to,
        uint256 _conversionId,
        uint256[] memory _signature
    )
        public
        payable
        returns (uint256)
    {
        return xConvertPrioritized3(_path, _amount, _minReturn, _toBlockchain, _to, _conversionId, _signature, address(0), 0);
    }

    /**
      * @dev deprecated, backward compatibility
    */
    function xConvertPrioritized(
        IERC20Token[] _path,
        uint256 _amount,
        uint256 _minReturn,
        bytes32 _toBlockchain,
        bytes32 _to,
        uint256 _conversionId,
        uint256 _block,
        uint8 _v,
        bytes32 _r,
        bytes32 _s
    )
        public
        payable
        returns (uint256)
    {
        // workaround the 'stack too deep' compilation error
        uint256[] memory signature = getSignature(_amount, _block, _v, _r, _s);
        return xConvertPrioritized3(_path, _amount, _minReturn, _toBlockchain, _to, _conversionId, signature, address(0), 0);
        // return xConvertPrioritized3(_path, _amount, _minReturn, _toBlockchain, _to, _conversionId, getSignature(_amount, _block, _v, _r, _s), address(0), 0);
    }

    /**
      * @dev deprecated, backward compatibility
    */
    function convertForPrioritized3(
        IERC20Token[] _path,
        uint256 _amount,
        uint256 _minReturn,
        address _for,
        uint256 _customVal,
        uint256 _block,
        uint8 _v,
        bytes32 _r,
        bytes32 _s
    )
        public
        payable
        returns (uint256)
    {
        return convertForPrioritized4(_path, _amount, _minReturn, _for, getSignature(_customVal, _block, _v, _r, _s), address(0), 0);
    }

    /**
      * @dev deprecated, backward compatibility
    */
    function convertForPrioritized2(
        IERC20Token[] _path,
        uint256 _amount,
        uint256 _minReturn,
        address _for,
        uint256 _block,
        uint8 _v,
        bytes32 _r,
        bytes32 _s
    )
        public
        payable
        returns (uint256)
    {
        return convertForPrioritized4(_path, _amount, _minReturn, _for, getSignature(_amount, _block, _v, _r, _s), address(0), 0);
    }

    /**
      * @dev deprecated, backward compatibility
    */
    function convertForPrioritized(
        IERC20Token[] _path,
        uint256 _amount,
        uint256 _minReturn,
        address _for,
        uint256 _block,
        uint256 _nonce,
        uint8 _v,
        bytes32 _r,
        bytes32 _s)
        public payable returns (uint256)
    {
        _nonce;
        return convertForPrioritized4(_path, _amount, _minReturn, _for, getSignature(_amount, _block, _v, _r, _s), address(0), 0);
    }
}

pragma solidity ^0.4.24;

// File: contracts/utility/interfaces/IOwned.sol

/*
    Owned contract interface
*/
contract IOwned {
    // this function isn't abstract since the compiler emits automatically generated getter functions as external
    function owner() public view returns (address) {}

    function transferOwnership(address _newOwner) public;
    function acceptOwnership() public;
}

// File: contracts/utility/Owned.sol

/*
    Provides support and utilities for contract ownership
*/
contract Owned is IOwned {
    address public owner;
    address public newOwner;

    event OwnerUpdate(address indexed _prevOwner, address indexed _newOwner);

    /**
        @dev constructor
    */
    constructor() public {
        owner = msg.sender;
    }

    // allows execution by the owner only
    modifier ownerOnly {
        require(msg.sender == owner);
        _;
    }

    /**
        @dev allows transferring the contract ownership
        the new owner still needs to accept the transfer
        can only be called by the contract owner

        @param _newOwner    new contract owner
    */
    function transferOwnership(address _newOwner) public ownerOnly {
        require(_newOwner != owner);
        newOwner = _newOwner;
    }

    /**
        @dev used by a new owner to accept an ownership transfer
    */
    function acceptOwnership() public {
        require(msg.sender == newOwner);
        emit OwnerUpdate(owner, newOwner);
        owner = newOwner;
        newOwner = address(0);
    }
}

// File: contracts/utility/Utils.sol

/*
    Utilities & Common Modifiers
*/
contract Utils {
    /**
        constructor
    */
    constructor() public {
    }

    // verifies that an amount is greater than zero
    modifier greaterThanZero(uint256 _amount) {
        require(_amount > 0);
        _;
    }

    // validates an address - currently only checks that it isn't null
    modifier validAddress(address _address) {
        require(_address != address(0));
        _;
    }

    // verifies that the address is different than this contract address
    modifier notThis(address _address) {
        require(_address != address(this));
        _;
    }

    // Overflow protected math functions

    /**
        @dev returns the sum of _x and _y, asserts if the calculation overflows

        @param _x   value 1
        @param _y   value 2

        @return sum
    */
    function safeAdd(uint256 _x, uint256 _y) internal pure returns (uint256) {
        uint256 z = _x + _y;
        assert(z >= _x);
        return z;
    }

    /**
        @dev returns the difference of _x minus _y, asserts if the subtraction results in a negative number

        @param _x   minuend
        @param _y   subtrahend

        @return difference
    */
    function safeSub(uint256 _x, uint256 _y) internal pure returns (uint256) {
        assert(_x >= _y);
        return _x - _y;
    }

    /**
        @dev returns the product of multiplying _x by _y, asserts if the calculation overflows

        @param _x   factor 1
        @param _y   factor 2

        @return product
    */
    function safeMul(uint256 _x, uint256 _y) internal pure returns (uint256) {
        uint256 z = _x * _y;
        assert(_x == 0 || z / _x == _y);
        return z;
    }
}

// File: contracts/utility/interfaces/IContractRegistry.sol

/*
    Contract Registry interface
*/
contract IContractRegistry {
    function addressOf(bytes32 _contractName) public view returns (address);

    // deprecated, backward compatibility
    function getAddress(bytes32 _contractName) public view returns (address);
}

// File: contracts/ContractIds.sol

/**
    Id definitions for bancor contracts

    Can be used in conjunction with the contract registry to get contract addresses
*/
contract ContractIds {
    // generic
    bytes32 public constant CONTRACT_FEATURES = "ContractFeatures";
    bytes32 public constant CONTRACT_REGISTRY = "ContractRegistry";

    // bancor logic
    bytes32 public constant BANCOR_NETWORK = "BancorNetwork";
    bytes32 public constant BANCOR_FORMULA = "BancorFormula";
    bytes32 public constant BANCOR_GAS_PRICE_LIMIT = "BancorGasPriceLimit";
    bytes32 public constant BANCOR_CONVERTER_UPGRADER = "BancorConverterUpgrader";
    bytes32 public constant BANCOR_CONVERTER_FACTORY = "BancorConverterFactory";

    // Ids of BNT converter and BNT token
    bytes32 public constant BNT_TOKEN = "BNTToken";
    bytes32 public constant BNT_CONVERTER = "BNTConverter";

    // Id of BancorX contract
    bytes32 public constant BANCOR_X = "BancorX";
}

// File: contracts/utility/ContractRegistry.sol

/**
    Contract Registry

    The contract registry keeps contract addresses by name.
    The owner can update contract addresses so that a contract name always points to the latest version
    of the given contract.
    Other contracts can query the registry to get updated addresses instead of depending on specific
    addresses.

    Note that contract names are limited to 32 bytes UTF8 encoded ASCII strings to optimize gas costs
*/
contract ContractRegistry is IContractRegistry, Owned, Utils, ContractIds {
    struct RegistryItem {
        address contractAddress;    // contract address
        uint256 nameIndex;          // index of the item in the list of contract names
        bool isSet;                 // used to tell if the mapping element is defined
    }

    mapping (bytes32 => RegistryItem) private items;    // name -> RegistryItem mapping
    string[] public contractNames;                      // list of all registered contract names

    // triggered when an address pointed to by a contract name is modified
    event AddressUpdate(bytes32 indexed _contractName, address _contractAddress);

    /**
        @dev constructor
    */
    constructor() public {
        registerAddress(ContractIds.CONTRACT_REGISTRY, address(this));
    }

    /**
        @dev returns the number of items in the registry

        @return number of items
    */
    function itemCount() public view returns (uint256) {
        return contractNames.length;
    }

    /**
        @dev returns the address associated with the given contract name

        @param _contractName    contract name

        @return contract address
    */
    function addressOf(bytes32 _contractName) public view returns (address) {
        return items[_contractName].contractAddress;
    }

    /**
        @dev registers a new address for the contract name in the registry

        @param _contractName     contract name
        @param _contractAddress  contract address
    */
    function registerAddress(bytes32 _contractName, address _contractAddress)
        public
        ownerOnly
        validAddress(_contractAddress)
    {
        require(_contractName.length > 0); // validate input

        // update the address in the registry
        items[_contractName].contractAddress = _contractAddress;

        if (!items[_contractName].isSet) {
            // mark the item as set
            items[_contractName].isSet = true;
            // add the contract name to the name list
            uint256 i = contractNames.push(bytes32ToString(_contractName));
            // update the item's index in the list
            items[_contractName].nameIndex = i - 1;
        }

        // dispatch the address update event
        emit AddressUpdate(_contractName, _contractAddress);
    }

    /**
        @dev removes an existing contract address from the registry

        @param _contractName contract name
    */
    function unregisterAddress(bytes32 _contractName) public ownerOnly {
        require(_contractName.length > 0); // validate input

        // remove the address from the registry
        items[_contractName].contractAddress = address(0);

        // if there are multiple items in the registry, move the last element to the deleted element's position
        // and modify last element's registryItem.nameIndex in the items collection to point to the right position in contractNames
        if (contractNames.length > 1) {
            string memory lastContractNameString = contractNames[contractNames.length - 1];
            uint256 unregisterIndex = items[_contractName].nameIndex;

            contractNames[unregisterIndex] = lastContractNameString;
            bytes32 lastContractName = stringToBytes32(lastContractNameString);
            RegistryItem storage registryItem = items[lastContractName];
            registryItem.nameIndex = unregisterIndex;
        }

        // remove the last element from the name list
        contractNames.length--;
        // zero the deleted element's index
        items[_contractName].nameIndex = 0;

        // dispatch the address update event
        emit AddressUpdate(_contractName, address(0));
    }

    /**
        @dev utility, converts bytes32 to a string
        note that the bytes32 argument is assumed to be UTF8 encoded ASCII string

        @return string representation of the given bytes32 argument
    */
    function bytes32ToString(bytes32 _bytes) private pure returns (string) {
        bytes memory byteArray = new bytes(32);
        for (uint256 i; i < 32; i++) {
            byteArray[i] = _bytes[i];
        }

        return string(byteArray);
    }

    // @dev utility, converts string to bytes32
    function stringToBytes32(string memory _string) private pure returns (bytes32) {
        bytes32 result;
        assembly {
            result := mload(add(_string,32))
        }
        return result;
    }

    // deprecated, backward compatibility
    function getAddress(bytes32 _contractName) public view returns (address) {
        return addressOf(_contractName);
    }
}

pragma solidity 0.4.26;

// File: contracts/token/interfaces/IERC20Token.sol

/*
    ERC20 Standard Token interface
*/
contract IERC20Token {
    // these functions aren't abstract since the compiler emits automatically generated getter functions as external
    function name() public view returns (string) {this;}
    function symbol() public view returns (string) {this;}
    function decimals() public view returns (uint8) {this;}
    function totalSupply() public view returns (uint256) {this;}
    function balanceOf(address _owner) public view returns (uint256) {_owner; this;}
    function allowance(address _owner, address _spender) public view returns (uint256) {_owner; _spender; this;}

    function transfer(address _to, uint256 _value) public returns (bool success);
    function transferFrom(address _from, address _to, uint256 _value) public returns (bool success);
    function approve(address _spender, uint256 _value) public returns (bool success);
}

// File: contracts/utility/Utils.sol

/**
  * @dev Utilities & Common Modifiers
*/
contract Utils {
    /**
      * constructor
    */
    constructor() public {
    }

    // verifies that an amount is greater than zero
    modifier greaterThanZero(uint256 _amount) {
        require(_amount > 0);
        _;
    }

    // validates an address - currently only checks that it isn't null
    modifier validAddress(address _address) {
        require(_address != address(0));
        _;
    }

    // verifies that the address is different than this contract address
    modifier notThis(address _address) {
        require(_address != address(this));
        _;
    }

}

// File: contracts/utility/SafeMath.sol

/**
  * @dev Library for basic math operations with overflow/underflow protection
*/
library SafeMath {
    /**
      * @dev returns the sum of _x and _y, reverts if the calculation overflows
      * 
      * @param _x   value 1
      * @param _y   value 2
      * 
      * @return sum
    */
    function add(uint256 _x, uint256 _y) internal pure returns (uint256) {
        uint256 z = _x + _y;
        require(z >= _x);
        return z;
    }

    /**
      * @dev returns the difference of _x minus _y, reverts if the calculation underflows
      * 
      * @param _x   minuend
      * @param _y   subtrahend
      * 
      * @return difference
    */
    function sub(uint256 _x, uint256 _y) internal pure returns (uint256) {
        require(_x >= _y);
        return _x - _y;
    }

    /**
      * @dev returns the product of multiplying _x by _y, reverts if the calculation overflows
      * 
      * @param _x   factor 1
      * @param _y   factor 2
      * 
      * @return product
    */
    function mul(uint256 _x, uint256 _y) internal pure returns (uint256) {
        // gas optimization
        if (_x == 0)
            return 0;

        uint256 z = _x * _y;
        require(z / _x == _y);
        return z;
    }

      /**
        * ev Integer division of two numbers truncating the quotient, reverts on division by zero.
        * 
        * aram _x   dividend
        * aram _y   divisor
        * 
        * eturn quotient
    */
    function div(uint256 _x, uint256 _y) internal pure returns (uint256) {
        require(_y > 0);
        uint256 c = _x / _y;

        return c;
    }
}

// File: contracts/token/ERC20Token.sol

/**
  * @dev ERC20 Standard Token implementation
*/
contract ERC20Token is IERC20Token, Utils {
    using SafeMath for uint256;


    string public name;
    string public symbol;
    uint8 public decimals;
    uint256 public totalSupply;
    mapping (address => uint256) public balanceOf;
    mapping (address => mapping (address => uint256)) public allowance;

    /**
      * @dev triggered when tokens are transferred between wallets
      * 
      * @param _from    source address
      * @param _to      target address
      * @param _value   transfer amount
    */
    event Transfer(address indexed _from, address indexed _to, uint256 _value);

    /**
      * @dev triggered when a wallet allows another wallet to transfer tokens from on its behalf
      * 
      * @param _owner   wallet that approves the allowance
      * @param _spender wallet that receives the allowance
      * @param _value   allowance amount
    */
    event Approval(address indexed _owner, address indexed _spender, uint256 _value);

    /**
      * @dev initializes a new ERC20Token instance
      * 
      * @param _name        token name
      * @param _symbol      token symbol
      * @param _decimals    decimal points, for display purposes
      * @param _totalSupply total supply of token units
    */
    constructor(string _name, string _symbol, uint8 _decimals, uint256 _totalSupply) public {
        require(bytes(_name).length > 0 && bytes(_symbol).length > 0); // validate input

        name = _name;
        symbol = _symbol;
        decimals = _decimals;
        totalSupply = _totalSupply;
        balanceOf[msg.sender] = _totalSupply;
    }

    /**
      * @dev send coins
      * throws on any error rather then return a false flag to minimize user errors
      * 
      * @param _to      target address
      * @param _value   transfer amount
      * 
      * @return true if the transfer was successful, false if it wasn't
    */
    function transfer(address _to, uint256 _value)
        public
        validAddress(_to)
        returns (bool success)
    {
        balanceOf[msg.sender] = balanceOf[msg.sender].sub(_value);
        balanceOf[_to] = balanceOf[_to].add(_value);
        emit Transfer(msg.sender, _to, _value);
        return true;
    }

    /**
      * @dev an account/contract attempts to get the coins
      * throws on any error rather then return a false flag to minimize user errors
      * 
      * @param _from    source address
      * @param _to      target address
      * @param _value   transfer amount
      * 
      * @return true if the transfer was successful, false if it wasn't
    */
    function transferFrom(address _from, address _to, uint256 _value)
        public
        validAddress(_from)
        validAddress(_to)
        returns (bool success)
    {
        allowance[_from][msg.sender] = allowance[_from][msg.sender].sub(_value);
        balanceOf[_from] = balanceOf[_from].sub(_value);
        balanceOf[_to] = balanceOf[_to].add(_value);
        emit Transfer(_from, _to, _value);
        return true;
    }

    /**
      * @dev allow another account/contract to spend some tokens on your behalf
      * throws on any error rather then return a false flag to minimize user errors
      * 
      * also, to minimize the risk of the approve/transferFrom attack vector
      * (see https://docs.google.com/document/d/1YLPtQxZu1UAvO9cZ1O2RPXBbT0mooh4DYKjA_jp-RLM/), approve has to be called twice
      * in 2 separate transactions - once to change the allowance to 0 and secondly to change it to the new allowance value
      * 
      * @param _spender approved address
      * @param _value   allowance amount
      * 
      * @return true if the approval was successful, false if it wasn't
    */
    function approve(address _spender, uint256 _value)
        public
        validAddress(_spender)
        returns (bool success)
    {
        // if the allowance isn't 0, it can only be updated to 0 to prevent an allowance change immediately after withdrawal
        require(_value == 0 || allowance[msg.sender][_spender] == 0);

        allowance[msg.sender][_spender] = _value;
        emit Approval(msg.sender, _spender, _value);
        return true;
    }
}

// File: contracts/utility/interfaces/IOwned.sol

/*
    Owned contract interface
*/
contract IOwned {
    // this function isn't abstract since the compiler emits automatically generated getter functions as external
    function owner() public view returns (address) {this;}

    function transferOwnership(address _newOwner) public;
    function acceptOwnership() public;
}

// File: contracts/token/interfaces/ISmartToken.sol

/*
    Smart Token interface
*/
contract ISmartToken is IOwned, IERC20Token {
    function disableTransfers(bool _disable) public;
    function issue(address _to, uint256 _amount) public;
    function destroy(address _from, uint256 _amount) public;
}

// File: contracts/utility/Owned.sol

/**
  * @dev Provides support and utilities for contract ownership
*/
contract Owned is IOwned {
    address public owner;
    address public newOwner;

    /**
      * @dev triggered when the owner is updated
      * 
      * @param _prevOwner previous owner
      * @param _newOwner  new owner
    */
    event OwnerUpdate(address indexed _prevOwner, address indexed _newOwner);

    /**
      * @dev initializes a new Owned instance
    */
    constructor() public {
        owner = msg.sender;
    }

    // allows execution by the owner only
    modifier ownerOnly {
        require(msg.sender == owner);
        _;
    }

    /**
      * @dev allows transferring the contract ownership
      * the new owner still needs to accept the transfer
      * can only be called by the contract owner
      * 
      * @param _newOwner    new contract owner
    */
    function transferOwnership(address _newOwner) public ownerOnly {
        require(_newOwner != owner);
        newOwner = _newOwner;
    }

    /**
      * @dev used by a new owner to accept an ownership transfer
    */
    function acceptOwnership() public {
        require(msg.sender == newOwner);
        emit OwnerUpdate(owner, newOwner);
        owner = newOwner;
        newOwner = address(0);
    }
}

// File: contracts/utility/interfaces/ITokenHolder.sol

/*
    Token Holder interface
*/
contract ITokenHolder is IOwned {
    function withdrawTokens(IERC20Token _token, address _to, uint256 _amount) public;
}

// File: contracts/token/interfaces/INonStandardERC20.sol

/*
    ERC20 Standard Token interface which doesn't return true/false for transfer, transferFrom and approve
*/
contract INonStandardERC20 {
    // these functions aren't abstract since the compiler emits automatically generated getter functions as external
    function name() public view returns (string) {this;}
    function symbol() public view returns (string) {this;}
    function decimals() public view returns (uint8) {this;}
    function totalSupply() public view returns (uint256) {this;}
    function balanceOf(address _owner) public view returns (uint256) {_owner; this;}
    function allowance(address _owner, address _spender) public view returns (uint256) {_owner; _spender; this;}

    function transfer(address _to, uint256 _value) public;
    function transferFrom(address _from, address _to, uint256 _value) public;
    function approve(address _spender, uint256 _value) public;
}

// File: contracts/utility/TokenHolder.sol

/**
  * @dev We consider every contract to be a 'token holder' since it's currently not possible
  * for a contract to deny receiving tokens.
  * 
  * The TokenHolder's contract sole purpose is to provide a safety mechanism that allows
  * the owner to send tokens that were sent to the contract by mistake back to their sender.
  * 
  * Note that we use the non standard ERC-20 interface which has no return value for transfer
  * in order to support both non standard as well as standard token contracts.
  * see https://github.com/ethereum/solidity/issues/4116
*/
contract TokenHolder is ITokenHolder, Owned, Utils {
    /**
      * @dev initializes a new TokenHolder instance
    */
    constructor() public {
    }

    /**
      * @dev withdraws tokens held by the contract and sends them to an account
      * can only be called by the owner
      * 
      * @param _token   ERC20 token contract address
      * @param _to      account to receive the new amount
      * @param _amount  amount to withdraw
    */
    function withdrawTokens(IERC20Token _token, address _to, uint256 _amount)
        public
        ownerOnly
        validAddress(_token)
        validAddress(_to)
        notThis(_to)
    {
        INonStandardERC20(_token).transfer(_to, _amount);
    }
}

// File: contracts/token/SmartToken.sol

/**
  * @dev Smart Token
  * 
  * 'Owned' is specified here for readability reasons
*/
contract SmartToken is ISmartToken, Owned, ERC20Token, TokenHolder {
    using SafeMath for uint256;


    string public version = '0.3';

    bool public transfersEnabled = true;    // true if transfer/transferFrom are enabled, false if not

    /**
      * @dev triggered when a smart token is deployed
      * the _token address is defined for forward compatibility, in case the event is trigger by a factory
      * 
      * @param _token  new smart token address
    */
    event NewSmartToken(address _token);

    /**
      * @dev triggered when the total supply is increased
      * 
      * @param _amount  amount that gets added to the supply
    */
    event Issuance(uint256 _amount);

    /**
      * @dev triggered when the total supply is decreased
      * 
      * @param _amount  amount that gets removed from the supply
    */
    event Destruction(uint256 _amount);

    /**
      * @dev initializes a new SmartToken instance
      * 
      * @param _name       token name
      * @param _symbol     token short symbol, minimum 1 character
      * @param _decimals   for display purposes only
    */
    constructor(string _name, string _symbol, uint8 _decimals)
        public
        ERC20Token(_name, _symbol, _decimals, 0)
    {
        emit NewSmartToken(address(this));
    }

    // allows execution only when transfers aren't disabled
    modifier transfersAllowed {
        assert(transfersEnabled);
        _;
    }

    /**
      * @dev disables/enables transfers
      * can only be called by the contract owner
      * 
      * @param _disable    true to disable transfers, false to enable them
    */
    function disableTransfers(bool _disable) public ownerOnly {
        transfersEnabled = !_disable;
    }

    /**
      * @dev increases the token supply and sends the new tokens to an account
      * can only be called by the contract owner
      * 
      * @param _to         account to receive the new amount
      * @param _amount     amount to increase the supply by
    */
    function issue(address _to, uint256 _amount)
        public
        ownerOnly
        validAddress(_to)
        notThis(_to)
    {
        totalSupply = totalSupply.add(_amount);
        balanceOf[_to] = balanceOf[_to].add(_amount);

        emit Issuance(_amount);
        emit Transfer(this, _to, _amount);
    }

    /**
      * @dev removes tokens from an account and decreases the token supply
      * can be called by the contract owner to destroy tokens from any account or by any holder to destroy tokens from his/her own account
      * 
      * @param _from       account to remove the amount from
      * @param _amount     amount to decrease the supply by
    */
    function destroy(address _from, uint256 _amount) public {
        require(msg.sender == _from || msg.sender == owner); // validate input

        balanceOf[_from] = balanceOf[_from].sub(_amount);
        totalSupply = totalSupply.sub(_amount);

        emit Transfer(_from, this, _amount);
        emit Destruction(_amount);
    }

    // ERC20 standard method overrides with some extra functionality

    /**
      * @dev send coins
      * throws on any error rather then return a false flag to minimize user errors
      * in addition to the standard checks, the function throws if transfers are disabled
      * 
      * @param _to      target address
      * @param _value   transfer amount
      * 
      * @return true if the transfer was successful, false if it wasn't
    */
    function transfer(address _to, uint256 _value) public transfersAllowed returns (bool success) {
        assert(super.transfer(_to, _value));
        return true;
    }

    /**
      * @dev an account/contract attempts to get the coins
      * throws on any error rather then return a false flag to minimize user errors
      * in addition to the standard checks, the function throws if transfers are disabled
      * 
      * @param _from    source address
      * @param _to      target address
      * @param _value   transfer amount
      * 
      * @return true if the transfer was successful, false if it wasn't
    */
    function transferFrom(address _from, address _to, uint256 _value) public transfersAllowed returns (bool success) {
        assert(super.transferFrom(_from, _to, _value));
        return true;
    }
}

pragma solidity ^0.4.21;

/*
    Contract Features interface
*/
contract IContractFeatures {
    function isSupported(address _contract, uint256 _features) public view returns (bool);
    function enableFeatures(uint256 _features, bool _enable) public;
}

/**
    Contract Features

    Generic contract that allows every contract on the blockchain to define which features it supports.
    Other contracts can query this contract to find out whether a given contract on the
    blockchain supports a certain feature.
    Each contract type can define its own list of feature flags.
    Features can be only enabled/disabled by the contract they are defined for.

    Features should be defined by each contract type as bit flags, e.g. -
    uint256 public constant FEATURE1 = 1 << 0;
    uint256 public constant FEATURE2 = 1 << 1;
    uint256 public constant FEATURE3 = 1 << 2;
    ...
*/
contract ContractFeatures is IContractFeatures {
    mapping (address => uint256) private featureFlags;

    event FeaturesAddition(address indexed _address, uint256 _features);
    event FeaturesRemoval(address indexed _address, uint256 _features);

    /**
        @dev constructor
    */
    function ContractFeatures() public {
    }

    /**
        @dev returns true if a given contract supports the given feature(s), false if not

        @param _contract    contract address to check support for
        @param _features    feature(s) to check for

        @return true if the contract supports the feature(s), false if not
    */
    function isSupported(address _contract, uint256 _features) public view returns (bool) {
        return (featureFlags[_contract] & _features) == _features;
    }

    /**
        @dev allows a contract to enable/disable certain feature(s)

        @param _features    feature(s) to enable/disable
        @param _enable      true to enable the feature(s), false to disabled them
    */
    function enableFeatures(uint256 _features, bool _enable) public {
        if (_enable) {
            if (isSupported(msg.sender, _features))
                return;

            featureFlags[msg.sender] |= _features;

            emit FeaturesAddition(msg.sender, _features);
        } else {
            if (!isSupported(msg.sender, _features))
                return;

            featureFlags[msg.sender] &= ~_features;

            emit FeaturesRemoval(msg.sender, _features);
        }
    }
}

// File: contracts/token/interfaces/IERC20Token.sol

pragma solidity 0.4.26;

/*
    ERC20 Standard Token interface
*/
contract IERC20Token {
    // these functions aren't abstract since the compiler emits automatically generated getter functions as external
    function name() public view returns (string) {this;}
    function symbol() public view returns (string) {this;}
    function decimals() public view returns (uint8) {this;}
    function totalSupply() public view returns (uint256) {this;}
    function balanceOf(address _owner) public view returns (uint256) {_owner; this;}
    function allowance(address _owner, address _spender) public view returns (uint256) {_owner; _spender; this;}

    function transfer(address _to, uint256 _value) public returns (bool success);
    function transferFrom(address _from, address _to, uint256 _value) public returns (bool success);
    function approve(address _spender, uint256 _value) public returns (bool success);
}

// File: contracts/utility/interfaces/IWhitelist.sol

pragma solidity 0.4.26;

/*
    Whitelist interface
*/
contract IWhitelist {
    function isWhitelisted(address _address) public view returns (bool);
}

// File: contracts/converter/interfaces/IBancorConverter.sol

pragma solidity 0.4.26;



/*
    Bancor Converter interface
*/
contract IBancorConverter {
    function getReturn(IERC20Token _fromToken, IERC20Token _toToken, uint256 _amount) public view returns (uint256, uint256);
    function convert2(IERC20Token _fromToken, IERC20Token _toToken, uint256 _amount, uint256 _minReturn, address _affiliateAccount, uint256 _affiliateFee) public returns (uint256);
    function quickConvert2(IERC20Token[] _path, uint256 _amount, uint256 _minReturn, address _affiliateAccount, uint256 _affiliateFee) public payable returns (uint256);
    function conversionsEnabled() public view returns (bool) {this;}
    function conversionWhitelist() public view returns (IWhitelist) {this;}
    function conversionFee() public view returns (uint32) {this;}
    function reserves(address _address) public view returns (uint256, uint32, bool, bool, bool) {_address; this;}
    function getReserveBalance(IERC20Token _reserveToken) public view returns (uint256);
    function reserveTokens(uint256 _index) public view returns (IERC20Token) {_index; this;}
    // deprecated, backward compatibility
    function change(IERC20Token _fromToken, IERC20Token _toToken, uint256 _amount, uint256 _minReturn) public returns (uint256);
    function convert(IERC20Token _fromToken, IERC20Token _toToken, uint256 _amount, uint256 _minReturn) public returns (uint256);
    function quickConvert(IERC20Token[] _path, uint256 _amount, uint256 _minReturn) public payable returns (uint256);
    function connectors(address _address) public view returns (uint256, uint32, bool, bool, bool);
    function getConnectorBalance(IERC20Token _connectorToken) public view returns (uint256);
    function connectorTokens(uint256 _index) public view returns (IERC20Token);
    function connectorTokenCount() public view returns (uint16);
}

// File: contracts/converter/interfaces/IBancorConverterUpgrader.sol

pragma solidity 0.4.26;


/*
    Bancor Converter Upgrader interface
*/
contract IBancorConverterUpgrader {
    function upgrade(bytes32 _version) public;
    function upgrade(uint16 _version) public;
}

// File: contracts/converter/interfaces/IBancorFormula.sol

pragma solidity 0.4.26;

/*
    Bancor Formula interface
*/
contract IBancorFormula {
    function calculatePurchaseReturn(uint256 _supply, uint256 _reserveBalance, uint32 _reserveRatio, uint256 _depositAmount) public view returns (uint256);
    function calculateSaleReturn(uint256 _supply, uint256 _reserveBalance, uint32 _reserveRatio, uint256 _sellAmount) public view returns (uint256);
    function calculateCrossReserveReturn(uint256 _fromReserveBalance, uint32 _fromReserveRatio, uint256 _toReserveBalance, uint32 _toReserveRatio, uint256 _amount) public view returns (uint256);
    function calculateFundCost(uint256 _supply, uint256 _reserveBalance, uint32 _totalRatio, uint256 _amount) public view returns (uint256);
    function calculateLiquidateReturn(uint256 _supply, uint256 _reserveBalance, uint32 _totalRatio, uint256 _amount) public view returns (uint256);
    // deprecated, backward compatibility
    function calculateCrossConnectorReturn(uint256 _fromConnectorBalance, uint32 _fromConnectorWeight, uint256 _toConnectorBalance, uint32 _toConnectorWeight, uint256 _amount) public view returns (uint256);
}

// File: contracts/IBancorNetwork.sol

pragma solidity 0.4.26;


/*
    Bancor Network interface
*/
contract IBancorNetwork {
    function convert2(
        IERC20Token[] _path,
        uint256 _amount,
        uint256 _minReturn,
        address _affiliateAccount,
        uint256 _affiliateFee
    ) public payable returns (uint256);

    function claimAndConvert2(
        IERC20Token[] _path,
        uint256 _amount,
        uint256 _minReturn,
        address _affiliateAccount,
        uint256 _affiliateFee
    ) public returns (uint256);

    function convertFor2(
        IERC20Token[] _path,
        uint256 _amount,
        uint256 _minReturn,
        address _for,
        address _affiliateAccount,
        uint256 _affiliateFee
    ) public payable returns (uint256);

    function claimAndConvertFor2(
        IERC20Token[] _path,
        uint256 _amount,
        uint256 _minReturn,
        address _for,
        address _affiliateAccount,
        uint256 _affiliateFee
    ) public returns (uint256);

    function convertForPrioritized4(
        IERC20Token[] _path,
        uint256 _amount,
        uint256 _minReturn,
        address _for,
        uint256[] memory _signature,
        address _affiliateAccount,
        uint256 _affiliateFee
    ) public payable returns (uint256);

    // deprecated, backward compatibility
    function convert(
        IERC20Token[] _path,
        uint256 _amount,
        uint256 _minReturn
    ) public payable returns (uint256);

    // deprecated, backward compatibility
    function claimAndConvert(
        IERC20Token[] _path,
        uint256 _amount,
        uint256 _minReturn
    ) public returns (uint256);

    // deprecated, backward compatibility
    function convertFor(
        IERC20Token[] _path,
        uint256 _amount,
        uint256 _minReturn,
        address _for
    ) public payable returns (uint256);

    // deprecated, backward compatibility
    function claimAndConvertFor(
        IERC20Token[] _path,
        uint256 _amount,
        uint256 _minReturn,
        address _for
    ) public returns (uint256);

    // deprecated, backward compatibility
    function convertForPrioritized3(
        IERC20Token[] _path,
        uint256 _amount,
        uint256 _minReturn,
        address _for,
        uint256 _customVal,
        uint256 _block,
        uint8 _v,
        bytes32 _r,
        bytes32 _s
    ) public payable returns (uint256);

    // deprecated, backward compatibility
    function convertForPrioritized2(
        IERC20Token[] _path,
        uint256 _amount,
        uint256 _minReturn,
        address _for,
        uint256 _block,
        uint8 _v,
        bytes32 _r,
        bytes32 _s
    ) public payable returns (uint256);

    // deprecated, backward compatibility
    function convertForPrioritized(
        IERC20Token[] _path,
        uint256 _amount,
        uint256 _minReturn,
        address _for,
        uint256 _block,
        uint256 _nonce,
        uint8 _v,
        bytes32 _r,
        bytes32 _s
    ) public payable returns (uint256);
}

// File: contracts/FeatureIds.sol

pragma solidity 0.4.26;

/**
  * @dev Id definitions for bancor contract features
  * 
  * Can be used to query the ContractFeatures contract to check whether a certain feature is supported by a contract
*/
contract FeatureIds {
    // converter features
    uint256 public constant CONVERTER_CONVERSION_WHITELIST = 1 << 0;
}

// File: contracts/utility/interfaces/IOwned.sol

pragma solidity 0.4.26;

/*
    Owned contract interface
*/
contract IOwned {
    // this function isn't abstract since the compiler emits automatically generated getter functions as external
    function owner() public view returns (address) {this;}

    function transferOwnership(address _newOwner) public;
    function acceptOwnership() public;
}

// File: contracts/utility/Owned.sol

pragma solidity 0.4.26;


/**
  * @dev Provides support and utilities for contract ownership
*/
contract Owned is IOwned {
    address public owner;
    address public newOwner;

    /**
      * @dev triggered when the owner is updated
      * 
      * @param _prevOwner previous owner
      * @param _newOwner  new owner
    */
    event OwnerUpdate(address indexed _prevOwner, address indexed _newOwner);

    /**
      * @dev initializes a new Owned instance
    */
    constructor() public {
        owner = msg.sender;
    }

    // allows execution by the owner only
    modifier ownerOnly {
        require(msg.sender == owner);
        _;
    }

    /**
      * @dev allows transferring the contract ownership
      * the new owner still needs to accept the transfer
      * can only be called by the contract owner
      * 
      * @param _newOwner    new contract owner
    */
    function transferOwnership(address _newOwner) public ownerOnly {
        require(_newOwner != owner);
        newOwner = _newOwner;
    }

    /**
      * @dev used by a new owner to accept an ownership transfer
    */
    function acceptOwnership() public {
        require(msg.sender == newOwner);
        emit OwnerUpdate(owner, newOwner);
        owner = newOwner;
        newOwner = address(0);
    }
}

// File: contracts/utility/Managed.sol

pragma solidity 0.4.26;


/**
  * @dev Provides support and utilities for contract management
  * Note that a managed contract must also have an owner
*/
contract Managed is Owned {
    address public manager;
    address public newManager;

    /**
      * @dev triggered when the manager is updated
      * 
      * @param _prevManager previous manager
      * @param _newManager  new manager
    */
    event ManagerUpdate(address indexed _prevManager, address indexed _newManager);

    /**
      * @dev initializes a new Managed instance
    */
    constructor() public {
        manager = msg.sender;
    }

    // allows execution by the manager only
    modifier managerOnly {
        assert(msg.sender == manager);
        _;
    }

    // allows execution by either the owner or the manager only
    modifier ownerOrManagerOnly {
        require(msg.sender == owner || msg.sender == manager);
        _;
    }

    /**
      * @dev allows transferring the contract management
      * the new manager still needs to accept the transfer
      * can only be called by the contract manager
      * 
      * @param _newManager    new contract manager
    */
    function transferManagement(address _newManager) public ownerOrManagerOnly {
        require(_newManager != manager);
        newManager = _newManager;
    }

    /**
      * @dev used by a new manager to accept a management transfer
    */
    function acceptManagement() public {
        require(msg.sender == newManager);
        emit ManagerUpdate(manager, newManager);
        manager = newManager;
        newManager = address(0);
    }
}

// File: contracts/utility/SafeMath.sol

pragma solidity 0.4.26;

/**
  * @dev Library for basic math operations with overflow/underflow protection
*/
library SafeMath {
    /**
      * @dev returns the sum of _x and _y, reverts if the calculation overflows
      * 
      * @param _x   value 1
      * @param _y   value 2
      * 
      * @return sum
    */
    function add(uint256 _x, uint256 _y) internal pure returns (uint256) {
        uint256 z = _x + _y;
        require(z >= _x);
        return z;
    }

    /**
      * @dev returns the difference of _x minus _y, reverts if the calculation underflows
      * 
      * @param _x   minuend
      * @param _y   subtrahend
      * 
      * @return difference
    */
    function sub(uint256 _x, uint256 _y) internal pure returns (uint256) {
        require(_x >= _y);
        return _x - _y;
    }

    /**
      * @dev returns the product of multiplying _x by _y, reverts if the calculation overflows
      * 
      * @param _x   factor 1
      * @param _y   factor 2
      * 
      * @return product
    */
    function mul(uint256 _x, uint256 _y) internal pure returns (uint256) {
        // gas optimization
        if (_x == 0)
            return 0;

        uint256 z = _x * _y;
        require(z / _x == _y);
        return z;
    }

      /**
        * ev Integer division of two numbers truncating the quotient, reverts on division by zero.
        * 
        * aram _x   dividend
        * aram _y   divisor
        * 
        * eturn quotient
    */
    function div(uint256 _x, uint256 _y) internal pure returns (uint256) {
        require(_y > 0);
        uint256 c = _x / _y;

        return c;
    }
}

// File: contracts/utility/Utils.sol

pragma solidity 0.4.26;

/**
  * @dev Utilities & Common Modifiers
*/
contract Utils {
    /**
      * constructor
    */
    constructor() public {
    }

    // verifies that an amount is greater than zero
    modifier greaterThanZero(uint256 _amount) {
        require(_amount > 0);
        _;
    }

    // validates an address - currently only checks that it isn't null
    modifier validAddress(address _address) {
        require(_address != address(0));
        _;
    }

    // verifies that the address is different than this contract address
    modifier notThis(address _address) {
        require(_address != address(this));
        _;
    }

}

// File: contracts/utility/interfaces/IContractRegistry.sol

pragma solidity 0.4.26;

/*
    Contract Registry interface
*/
contract IContractRegistry {
    function addressOf(bytes32 _contractName) public view returns (address);

    // deprecated, backward compatibility
    function getAddress(bytes32 _contractName) public view returns (address);
}

// File: contracts/utility/ContractRegistryClient.sol

pragma solidity 0.4.26;




/**
  * @dev Base contract for ContractRegistry clients
*/
contract ContractRegistryClient is Owned, Utils {
    bytes32 internal constant CONTRACT_FEATURES = "ContractFeatures";
    bytes32 internal constant CONTRACT_REGISTRY = "ContractRegistry";
    bytes32 internal constant BANCOR_NETWORK = "BancorNetwork";
    bytes32 internal constant BANCOR_FORMULA = "BancorFormula";
    bytes32 internal constant BANCOR_GAS_PRICE_LIMIT = "BancorGasPriceLimit";
    bytes32 internal constant BANCOR_CONVERTER_FACTORY = "BancorConverterFactory";
    bytes32 internal constant BANCOR_CONVERTER_UPGRADER = "BancorConverterUpgrader";
    bytes32 internal constant BANCOR_CONVERTER_REGISTRY = "BancorConverterRegistry";
    bytes32 internal constant BANCOR_CONVERTER_REGISTRY_DATA = "BancorConverterRegistryData";
    bytes32 internal constant BNT_TOKEN = "BNTToken";
    bytes32 internal constant BANCOR_X = "BancorX";
    bytes32 internal constant BANCOR_X_UPGRADER = "BancorXUpgrader";

    IContractRegistry public registry;      // address of the current contract-registry
    IContractRegistry public prevRegistry;  // address of the previous contract-registry
    bool public adminOnly;                  // only an administrator can update the contract-registry

    /**
      * @dev verifies that the caller is mapped to the given contract name
      * 
      * @param _contractName    contract name
    */
    modifier only(bytes32 _contractName) {
        require(msg.sender == addressOf(_contractName));
        _;
    }

    /**
      * @dev initializes a new ContractRegistryClient instance
      * 
      * @param  _registry   address of a contract-registry contract
    */
    constructor(IContractRegistry _registry) internal validAddress(_registry) {
        registry = IContractRegistry(_registry);
        prevRegistry = IContractRegistry(_registry);
    }

    /**
      * @dev updates to the new contract-registry
     */
    function updateRegistry() public {
        // verify that this function is permitted
        require(!adminOnly || isAdmin());

        // get the new contract-registry
        address newRegistry = addressOf(CONTRACT_REGISTRY);

        // verify that the new contract-registry is different and not zero
        require(newRegistry != address(registry) && newRegistry != address(0));

        // verify that the new contract-registry is pointing to a non-zero contract-registry
        require(IContractRegistry(newRegistry).addressOf(CONTRACT_REGISTRY) != address(0));

        // save a backup of the current contract-registry before replacing it
        prevRegistry = registry;

        // replace the current contract-registry with the new contract-registry
        registry = IContractRegistry(newRegistry);
    }

    /**
      * @dev restores the previous contract-registry
    */
    function restoreRegistry() public {
        // verify that this function is permitted
        require(isAdmin());

        // restore the previous contract-registry
        registry = prevRegistry;
    }

    /**
      * @dev restricts the permission to update the contract-registry
      * 
      * @param _adminOnly    indicates whether or not permission is restricted to administrator only
    */
    function restrictRegistryUpdate(bool _adminOnly) public {
        // verify that this function is permitted
        require(adminOnly != _adminOnly && isAdmin());

        // change the permission to update the contract-registry
        adminOnly = _adminOnly;
    }

    /**
      * @dev returns whether or not the caller is an administrator
     */
    function isAdmin() internal view returns (bool) {
        return msg.sender == owner;
    }

    /**
      * @dev returns the address associated with the given contract name
      * 
      * @param _contractName    contract name
      * 
      * @return contract address
    */
    function addressOf(bytes32 _contractName) internal view returns (address) {
        return registry.addressOf(_contractName);
    }
}

// File: contracts/utility/interfaces/IContractFeatures.sol

pragma solidity 0.4.26;

/*
    Contract Features interface
*/
contract IContractFeatures {
    function isSupported(address _contract, uint256 _features) public view returns (bool);
    function enableFeatures(uint256 _features, bool _enable) public;
}

// File: contracts/utility/interfaces/IAddressList.sol

pragma solidity 0.4.26;

/*
    Address list interface
*/
contract IAddressList {
    mapping (address => bool) public listedAddresses;
}

// File: contracts/token/interfaces/ISmartToken.sol

pragma solidity 0.4.26;



/*
    Smart Token interface
*/
contract ISmartToken is IOwned, IERC20Token {
    function disableTransfers(bool _disable) public;
    function issue(address _to, uint256 _amount) public;
    function destroy(address _from, uint256 _amount) public;
}

// File: contracts/token/interfaces/ISmartTokenController.sol

pragma solidity 0.4.26;


/*
    Smart Token Controller interface
*/
contract ISmartTokenController {
    function claimTokens(address _from, uint256 _amount) public;
    function token() public view returns (ISmartToken) {this;}
}

// File: contracts/utility/interfaces/ITokenHolder.sol

pragma solidity 0.4.26;



/*
    Token Holder interface
*/
contract ITokenHolder is IOwned {
    function withdrawTokens(IERC20Token _token, address _to, uint256 _amount) public;
}

// File: contracts/token/interfaces/INonStandardERC20.sol

pragma solidity 0.4.26;

/*
    ERC20 Standard Token interface which doesn't return true/false for transfer, transferFrom and approve
*/
contract INonStandardERC20 {
    // these functions aren't abstract since the compiler emits automatically generated getter functions as external
    function name() public view returns (string) {this;}
    function symbol() public view returns (string) {this;}
    function decimals() public view returns (uint8) {this;}
    function totalSupply() public view returns (uint256) {this;}
    function balanceOf(address _owner) public view returns (uint256) {_owner; this;}
    function allowance(address _owner, address _spender) public view returns (uint256) {_owner; _spender; this;}

    function transfer(address _to, uint256 _value) public;
    function transferFrom(address _from, address _to, uint256 _value) public;
    function approve(address _spender, uint256 _value) public;
}

// File: contracts/utility/TokenHolder.sol

pragma solidity 0.4.26;






/**
  * @dev We consider every contract to be a 'token holder' since it's currently not possible
  * for a contract to deny receiving tokens.
  * 
  * The TokenHolder's contract sole purpose is to provide a safety mechanism that allows
  * the owner to send tokens that were sent to the contract by mistake back to their sender.
  * 
  * Note that we use the non standard ERC-20 interface which has no return value for transfer
  * in order to support both non standard as well as standard token contracts.
  * see https://github.com/ethereum/solidity/issues/4116
*/
contract TokenHolder is ITokenHolder, Owned, Utils {
    /**
      * @dev initializes a new TokenHolder instance
    */
    constructor() public {
    }

    /**
      * @dev withdraws tokens held by the contract and sends them to an account
      * can only be called by the owner
      * 
      * @param _token   ERC20 token contract address
      * @param _to      account to receive the new amount
      * @param _amount  amount to withdraw
    */
    function withdrawTokens(IERC20Token _token, address _to, uint256 _amount)
        public
        ownerOnly
        validAddress(_token)
        validAddress(_to)
        notThis(_to)
    {
        INonStandardERC20(_token).transfer(_to, _amount);
    }
}

// File: contracts/token/SmartTokenController.sol

pragma solidity 0.4.26;




/**
  * @dev The smart token controller is an upgradable part of the smart token that allows
  * more functionality as well as fixes for bugs/exploits.
  * Once it accepts ownership of the token, it becomes the token's sole controller
  * that can execute any of its functions.
  * 
  * To upgrade the controller, ownership must be transferred to a new controller, along with
  * any relevant data.
  * 
  * The smart token must be set on construction and cannot be changed afterwards.
  * Wrappers are provided (as opposed to a single 'execute' function) for each of the token's functions, for easier access.
  * 
  * Note that the controller can transfer token ownership to a new controller that
  * doesn't allow executing any function on the token, for a trustless solution.
  * Doing that will also remove the owner's ability to upgrade the controller.
*/
contract SmartTokenController is ISmartTokenController, TokenHolder {
    ISmartToken public token;   // Smart Token contract
    address public bancorX;     // BancorX contract

    /**
      * @dev initializes a new SmartTokenController instance
      * 
      * @param  _token      smart token governed by the controller
    */
    constructor(ISmartToken _token)
        public
        validAddress(_token)
    {
        token = _token;
    }

    // ensures that the controller is the token's owner
    modifier active() {
        require(token.owner() == address(this));
        _;
    }

    // ensures that the controller is not the token's owner
    modifier inactive() {
        require(token.owner() != address(this));
        _;
    }

    /**
      * @dev allows transferring the token ownership
      * the new owner needs to accept the transfer
      * can only be called by the contract owner
      * 
      * @param _newOwner    new token owner
    */
    function transferTokenOwnership(address _newOwner) public ownerOnly {
        token.transferOwnership(_newOwner);
    }

    /**
      * @dev used by a new owner to accept a token ownership transfer
      * can only be called by the contract owner
    */
    function acceptTokenOwnership() public ownerOnly {
        token.acceptOwnership();
    }

    /**
      * @dev withdraws tokens held by the controller and sends them to an account
      * can only be called by the owner
      * 
      * @param _token   ERC20 token contract address
      * @param _to      account to receive the new amount
      * @param _amount  amount to withdraw
    */
    function withdrawFromToken(IERC20Token _token, address _to, uint256 _amount) public ownerOnly {
        ITokenHolder(token).withdrawTokens(_token, _to, _amount);
    }

    /**
      * @dev allows the associated BancorX contract to claim tokens from any address (so that users
      * dont have to first give allowance when calling BancorX)
      * 
      * @param _from      address to claim the tokens from
      * @param _amount    the amount of tokens to claim
     */
    function claimTokens(address _from, uint256 _amount) public {
        // only the associated BancorX contract may call this method
        require(msg.sender == bancorX);

        // destroy the tokens belonging to _from, and issue the same amount to bancorX
        token.destroy(_from, _amount);
        token.issue(msg.sender, _amount);
    }

    /**
      * @dev allows the owner to set the associated BancorX contract
      * @param _bancorX    BancorX contract
     */
    function setBancorX(address _bancorX) public ownerOnly {
        bancorX = _bancorX;
    }
}

// File: contracts/token/interfaces/IEtherToken.sol

pragma solidity 0.4.26;



/*
    Ether Token interface
*/
contract IEtherToken is ITokenHolder, IERC20Token {
    function deposit() public payable;
    function withdraw(uint256 _amount) public;
    function withdrawTo(address _to, uint256 _amount) public;
}

// File: contracts/bancorx/interfaces/IBancorX.sol

pragma solidity 0.4.26;

contract IBancorX {
    function xTransfer(bytes32 _toBlockchain, bytes32 _to, uint256 _amount, uint256 _id) public;
    function getXTransferAmount(uint256 _xTransferId, address _for) public view returns (uint256);
}

// File: contracts/converter/BancorConverter.sol

pragma solidity 0.4.26;
















/**
  * @dev Bancor Converter
  * 
  * The Bancor converter allows for conversions between a Smart Token and other ERC20 tokens and between different ERC20 tokens and themselves. 
  * 
  * The ERC20 reserve balance can be virtual, meaning that conversions between reserve tokens are based on the virtual balance instead of relying on the actual reserve balance.
  * 
  * This mechanism opens the possibility to create different financial tools (for example, lower slippage in conversions).
  * 
  * The converter is upgradable (just like any SmartTokenController) and all upgrades are opt-in. 
  * 
  * WARNING: It is NOT RECOMMENDED to use the converter with Smart Tokens that have less than 8 decimal digits or with very small numbers because of precision loss 
  * 
  * Open issues:
  * - Front-running attacks are currently mitigated by the following mechanisms:
  *     - minimum return argument for each conversion provides a way to define a minimum/maximum price for the transaction
  *     - gas price limit prevents users from having control over the order of execution
  *     - gas price limit check can be skipped if the transaction comes from a trusted, whitelisted signer
  * 
  * Other potential solutions might include a commit/reveal based schemes
  * - Possibly add getters for the reserve fields so that the client won't need to rely on the order in the struct
*/
contract BancorConverter is IBancorConverter, SmartTokenController, Managed, ContractRegistryClient, FeatureIds {
    using SafeMath for uint256;

    uint32 private constant RATIO_RESOLUTION = 1000000;
    uint64 private constant CONVERSION_FEE_RESOLUTION = 1000000;

    struct Reserve {
        uint256 virtualBalance;         // reserve virtual balance
        uint32 ratio;                   // reserve ratio, represented in ppm, 1-1000000
        bool isVirtualBalanceEnabled;   // true if virtual balance is enabled, false if not
        bool isSaleEnabled;             // is sale of the reserve token enabled, can be set by the owner
        bool isSet;                     // used to tell if the mapping element is defined
    }

    /**
      * @dev version number
    */
    uint16 public version = 23;
    string public converterType = 'bancor';

    IWhitelist public conversionWhitelist;              // whitelist contract with list of addresses that are allowed to use the converter
    IERC20Token[] public reserveTokens;                 // ERC20 standard token addresses (prior version 17, use 'connectorTokens' instead)
    mapping (address => Reserve) public reserves;       // reserve token addresses -> reserve data (prior version 17, use 'connectors' instead)
    uint32 private totalReserveRatio = 0;               // used to efficiently prevent increasing the total reserve ratio above 100%
    uint32 public maxConversionFee = 0;                 // maximum conversion fee for the lifetime of the contract,
                                                        // represented in ppm, 0...1000000 (0 = no fee, 100 = 0.01%, 1000000 = 100%)
    uint32 public conversionFee = 0;                    // current conversion fee, represented in ppm, 0...maxConversionFee
    bool public conversionsEnabled = true;              // true if token conversions is enabled, false if not

    /**
      * @dev triggered when a conversion between two tokens occurs
      * 
      * @param _fromToken       ERC20 token converted from
      * @param _toToken         ERC20 token converted to
      * @param _trader          wallet that initiated the trade
      * @param _amount          amount converted, in fromToken
      * @param _return          amount returned, minus conversion fee
      * @param _conversionFee   conversion fee
    */
    event Conversion(
        address indexed _fromToken,
        address indexed _toToken,
        address indexed _trader,
        uint256 _amount,
        uint256 _return,
        int256 _conversionFee
    );

    /**
      * @dev triggered after a conversion with new price data
      * 
      * @param  _connectorToken     reserve token
      * @param  _tokenSupply        smart token supply
      * @param  _connectorBalance   reserve balance
      * @param  _connectorWeight    reserve ratio
    */
    event PriceDataUpdate(
        address indexed _connectorToken,
        uint256 _tokenSupply,
        uint256 _connectorBalance,
        uint32 _connectorWeight
    );

    /**
      * @dev triggered when the conversion fee is updated
      * 
      * @param  _prevFee    previous fee percentage, represented in ppm
      * @param  _newFee     new fee percentage, represented in ppm
    */
    event ConversionFeeUpdate(uint32 _prevFee, uint32 _newFee);

    /**
      * @dev triggered when conversions are enabled/disabled
      * 
      * @param  _conversionsEnabled true if conversions are enabled, false if not
    */
    event ConversionsEnable(bool _conversionsEnabled);

    /**
      * @dev triggered when virtual balances are enabled/disabled
      * 
      * @param  _enabled true if virtual balances are enabled, false if not
    */
    event VirtualBalancesEnable(bool _enabled);

    /**
      * @dev initializes a new BancorConverter instance
      * 
      * @param  _token              smart token governed by the converter
      * @param  _registry           address of a contract registry contract
      * @param  _maxConversionFee   maximum conversion fee, represented in ppm
      * @param  _reserveToken       optional, initial reserve, allows defining the first reserve at deployment time
      * @param  _reserveRatio       optional, ratio for the initial reserve
    */
    constructor(
        ISmartToken _token,
        IContractRegistry _registry,
        uint32 _maxConversionFee,
        IERC20Token _reserveToken,
        uint32 _reserveRatio
    )   ContractRegistryClient(_registry)
        public
        SmartTokenController(_token)
        validConversionFee(_maxConversionFee)
    {
        IContractFeatures features = IContractFeatures(addressOf(CONTRACT_FEATURES));

        // initialize supported features
        if (features != address(0))
            features.enableFeatures(FeatureIds.CONVERTER_CONVERSION_WHITELIST, true);

        maxConversionFee = _maxConversionFee;

        if (_reserveToken != address(0))
            addReserve(_reserveToken, _reserveRatio);
    }

    // validates a reserve token address - verifies that the address belongs to one of the reserve tokens
    modifier validReserve(IERC20Token _address) {
        require(reserves[_address].isSet);
        _;
    }

    // validates conversion fee
    modifier validConversionFee(uint32 _conversionFee) {
        require(_conversionFee >= 0 && _conversionFee <= CONVERSION_FEE_RESOLUTION);
        _;
    }

    // validates reserve ratio
    modifier validReserveRatio(uint32 _ratio) {
        require(_ratio > 0 && _ratio <= RATIO_RESOLUTION);
        _;
    }

    // allows execution only when conversions aren't disabled
    modifier conversionsAllowed {
        require(conversionsEnabled);
        _;
    }

    // allows execution only if the total-supply of the token is greater than zero
    modifier totalSupplyGreaterThanZeroOnly {
        require(token.totalSupply() > 0);
        _;
    }

    // allows execution only on a multiple-reserve converter
    modifier multipleReservesOnly {
        require(reserveTokens.length > 1);
        _;
    }

    /**
      * @dev returns the number of reserve tokens defined
      * note that prior to version 17, you should use 'connectorTokenCount' instead
      * 
      * @return number of reserve tokens
    */
    function reserveTokenCount() public view returns (uint16) {
        return uint16(reserveTokens.length);
    }

    /**
      * @dev allows the owner to update & enable the conversion whitelist contract address
      * when set, only addresses that are whitelisted are actually allowed to use the converter
      * note that the whitelist check is actually done by the BancorNetwork contract
      * 
      * @param _whitelist    address of a whitelist contract
    */
    function setConversionWhitelist(IWhitelist _whitelist)
        public
        ownerOnly
        notThis(_whitelist)
    {
        conversionWhitelist = _whitelist;
    }

    /**
      * @dev disables the entire conversion functionality
      * this is a safety mechanism in case of a emergency
      * can only be called by the manager
      * 
      * @param _disable true to disable conversions, false to re-enable them
    */
    function disableConversions(bool _disable) public ownerOrManagerOnly {
        if (conversionsEnabled == _disable) {
            conversionsEnabled = !_disable;
            emit ConversionsEnable(conversionsEnabled);
        }
    }

    /**
      * @dev allows transferring the token ownership
      * the new owner needs to accept the transfer
      * can only be called by the contract owner
      * note that token ownership can only be transferred while the owner is the converter upgrader contract
      * 
      * @param _newOwner    new token owner
    */
    function transferTokenOwnership(address _newOwner)
        public
        ownerOnly
        only(BANCOR_CONVERTER_UPGRADER)
    {
        super.transferTokenOwnership(_newOwner);
    }

    /**
      * @dev used by a new owner to accept a token ownership transfer
      * can only be called by the contract owner
      * note that token ownership can only be accepted if its total-supply is greater than zero
    */
    function acceptTokenOwnership()
        public
        ownerOnly
        totalSupplyGreaterThanZeroOnly
    {
        super.acceptTokenOwnership();
    }

    /**
      * @dev updates the current conversion fee
      * can only be called by the manager
      * 
      * @param _conversionFee new conversion fee, represented in ppm
    */
    function setConversionFee(uint32 _conversionFee)
        public
        ownerOrManagerOnly
    {
        require(_conversionFee >= 0 && _conversionFee <= maxConversionFee);
        emit ConversionFeeUpdate(conversionFee, _conversionFee);
        conversionFee = _conversionFee;
    }

    /**
      * @dev given a return amount, returns the amount minus the conversion fee
      * 
      * @param _amount      return amount
      * @param _magnitude   1 for standard conversion, 2 for cross reserve conversion
      * 
      * @return return amount minus conversion fee
    */
    function getFinalAmount(uint256 _amount, uint8 _magnitude) public view returns (uint256) {
        return _amount.mul((CONVERSION_FEE_RESOLUTION - conversionFee) ** _magnitude).div(CONVERSION_FEE_RESOLUTION ** _magnitude);
    }

    /**
      * @dev withdraws tokens held by the converter and sends them to an account
      * can only be called by the owner
      * note that reserve tokens can only be withdrawn by the owner while the converter is inactive
      * unless the owner is the converter upgrader contract
      * 
      * @param _token   ERC20 token contract address
      * @param _to      account to receive the new amount
      * @param _amount  amount to withdraw
    */
    function withdrawTokens(IERC20Token _token, address _to, uint256 _amount) public {
        address converterUpgrader = addressOf(BANCOR_CONVERTER_UPGRADER);

        // if the token is not a reserve token, allow withdrawal
        // otherwise verify that the converter is inactive or that the owner is the upgrader contract
        require(!reserves[_token].isSet || token.owner() != address(this) || owner == converterUpgrader);
        super.withdrawTokens(_token, _to, _amount);
    }

    /**
      * @dev upgrades the converter to the latest version
      * can only be called by the owner
      * note that the owner needs to call acceptOwnership/acceptManagement on the new converter after the upgrade
    */
    function upgrade() public ownerOnly {
        IBancorConverterUpgrader converterUpgrader = IBancorConverterUpgrader(addressOf(BANCOR_CONVERTER_UPGRADER));

        transferOwnership(converterUpgrader);
        converterUpgrader.upgrade(version);
        acceptOwnership();
    }

    /**
      * @dev defines a new reserve for the token
      * can only be called by the owner while the converter is inactive
      * note that prior to version 17, you should use 'addConnector' instead
      * 
      * @param _token                  address of the reserve token
      * @param _ratio                  constant reserve ratio, represented in ppm, 1-1000000
    */
    function addReserve(IERC20Token _token, uint32 _ratio)
        public
        ownerOnly
        inactive
        validAddress(_token)
        notThis(_token)
        validReserveRatio(_ratio)
    {
        require(_token != token && !reserves[_token].isSet && totalReserveRatio + _ratio <= RATIO_RESOLUTION); // validate input

        reserves[_token].ratio = _ratio;
        reserves[_token].isVirtualBalanceEnabled = false;
        reserves[_token].virtualBalance = 0;
        reserves[_token].isSaleEnabled = true;
        reserves[_token].isSet = true;
        reserveTokens.push(_token);
        totalReserveRatio += _ratio;
    }

    /**
      * @dev updates a reserve's virtual balance
      * only used during an upgrade process
      * can only be called by the contract owner while the owner is the converter upgrader contract
      * note that prior to version 17, you should use 'updateConnector' instead
      * 
      * @param _reserveToken    address of the reserve token
      * @param _virtualBalance  new reserve virtual balance, or 0 to disable virtual balance
    */
    function updateReserveVirtualBalance(IERC20Token _reserveToken, uint256 _virtualBalance)
        public
        ownerOnly
        only(BANCOR_CONVERTER_UPGRADER)
        validReserve(_reserveToken)
    {
        Reserve storage reserve = reserves[_reserveToken];
        reserve.isVirtualBalanceEnabled = _virtualBalance != 0;
        reserve.virtualBalance = _virtualBalance;
    }

    /**
      * @dev enables virtual balance for the reserves
      * virtual balance only affects conversions between reserve tokens
      * virtual balance of all reserves can only scale by the same factor, to keep the ratio between them the same
      * note that the balance is determined during the execution of this function and set statically -
      * meaning that it's not calculated dynamically based on the factor after each conversion
      * can only be called by the contract owner while the converter is active
      * 
      * @param _scaleFactor  percentage, 100-1000 (100 = no virtual balance, 1000 = virtual balance = actual balance * 10)
    */
    function enableVirtualBalances(uint16 _scaleFactor)
        public
        ownerOnly
        active
    {
        // validate input
        require(_scaleFactor >= 100 && _scaleFactor <= 1000);
        bool enable = _scaleFactor != 100;

        // iterate through the reserves and scale their balance by the ratio provided,
        // or disable virtual balance altogether if a factor of 100% is passed in
        IERC20Token reserveToken;
        for (uint16 i = 0; i < reserveTokens.length; i++) {
            reserveToken = reserveTokens[i];
            Reserve storage reserve = reserves[reserveToken];
            reserve.isVirtualBalanceEnabled = enable;
            reserve.virtualBalance = enable ? reserveToken.balanceOf(this).mul(_scaleFactor).div(100) : 0;
        }

        emit VirtualBalancesEnable(enable);
    }

    /**
      * @dev disables converting from the given reserve token in case the reserve token got compromised
      * can only be called by the owner
      * note that converting to the token is still enabled regardless of this flag and it cannot be disabled by the owner
      * note that prior to version 17, you should use 'disableConnectorSale' instead
      * 
      * @param _reserveToken    reserve token contract address
      * @param _disable         true to disable the token, false to re-enable it
    */
    function disableReserveSale(IERC20Token _reserveToken, bool _disable)
        public
        ownerOnly
        validReserve(_reserveToken)
    {
        reserves[_reserveToken].isSaleEnabled = !_disable;
    }

    /**
      * @dev returns the reserve's ratio
      * added in version 22
      * 
      * @param _reserveToken    reserve token contract address
      * 
      * @return reserve ratio
    */
    function getReserveRatio(IERC20Token _reserveToken)
        public
        view
        validReserve(_reserveToken)
        returns (uint256)
    {
        return reserves[_reserveToken].ratio;
    }

    /**
      * @dev returns the reserve's virtual balance if one is defined, otherwise returns the actual balance
      * note that prior to version 17, you should use 'getConnectorBalance' instead
      * 
      * @param _reserveToken    reserve token contract address
      * 
      * @return reserve balance
    */
    function getReserveBalance(IERC20Token _reserveToken)
        public
        view
        validReserve(_reserveToken)
        returns (uint256)
    {
        Reserve storage reserve = reserves[_reserveToken];
        return reserve.isVirtualBalanceEnabled ? reserve.virtualBalance : _reserveToken.balanceOf(this);
    }

    /**
      * @dev calculates the expected return of converting a given amount of tokens
      * 
      * @param _fromToken  contract address of the token to convert from
      * @param _toToken    contract address of the token to convert to
      * @param _amount     amount of tokens received from the user
      * 
      * @return amount of tokens that the user will receive
      * @return amount of tokens that the user will pay as fee
    */
    function getReturn(IERC20Token _fromToken, IERC20Token _toToken, uint256 _amount) public view returns (uint256, uint256) {
        require(_fromToken != _toToken); // validate input

        // conversion between the token and one of its reserves
        if (_toToken == token)
            return getPurchaseReturn(_fromToken, _amount);
        else if (_fromToken == token)
            return getSaleReturn(_toToken, _amount);

        // conversion between 2 reserves
        return getCrossReserveReturn(_fromToken, _toToken, _amount);
    }

    /**
      * @dev calculates the expected return of buying with a given amount of tokens
      * 
      * @param _reserveToken    contract address of the reserve token
      * @param _depositAmount   amount of reserve-tokens received from the user
      * 
      * @return amount of supply-tokens that the user will receive
      * @return amount of supply-tokens that the user will pay as fee
    */
    function getPurchaseReturn(IERC20Token _reserveToken, uint256 _depositAmount)
        public
        view
        active
        validReserve(_reserveToken)
        returns (uint256, uint256)
    {
        Reserve storage reserve = reserves[_reserveToken];
        require(reserve.isSaleEnabled); // validate input

        uint256 tokenSupply = token.totalSupply();
        uint256 reserveBalance = _reserveToken.balanceOf(this);
        IBancorFormula formula = IBancorFormula(addressOf(BANCOR_FORMULA));
        uint256 amount = formula.calculatePurchaseReturn(tokenSupply, reserveBalance, reserve.ratio, _depositAmount);
        uint256 finalAmount = getFinalAmount(amount, 1);

        // return the amount minus the conversion fee and the conversion fee
        return (finalAmount, amount - finalAmount);
    }

    /**
      * @dev calculates the expected return of selling a given amount of tokens
      * 
      * @param _reserveToken    contract address of the reserve token
      * @param _sellAmount      amount of supply-tokens received from the user
      * 
      * @return amount of reserve-tokens that the user will receive
      * @return amount of reserve-tokens that the user will pay as fee
    */
    function getSaleReturn(IERC20Token _reserveToken, uint256 _sellAmount)
        public
        view
        active
        validReserve(_reserveToken)
        returns (uint256, uint256)
    {
        Reserve storage reserve = reserves[_reserveToken];
        uint256 tokenSupply = token.totalSupply();
        uint256 reserveBalance = _reserveToken.balanceOf(this);
        IBancorFormula formula = IBancorFormula(addressOf(BANCOR_FORMULA));
        uint256 amount = formula.calculateSaleReturn(tokenSupply, reserveBalance, reserve.ratio, _sellAmount);
        uint256 finalAmount = getFinalAmount(amount, 1);

        // return the amount minus the conversion fee and the conversion fee
        return (finalAmount, amount - finalAmount);
    }

    /**
      * @dev calculates the expected return of converting a given amount from one reserve to another
      * note that prior to version 17, you should use 'getCrossConnectorReturn' instead
      * 
      * @param _fromReserveToken    contract address of the reserve token to convert from
      * @param _toReserveToken      contract address of the reserve token to convert to
      * @param _amount              amount of tokens received from the user
      * 
      * @return amount of tokens that the user will receive
      * @return amount of tokens that the user will pay as fee
    */
    function getCrossReserveReturn(IERC20Token _fromReserveToken, IERC20Token _toReserveToken, uint256 _amount)
        public
        view
        active
        validReserve(_fromReserveToken)
        validReserve(_toReserveToken)
        returns (uint256, uint256)
    {
        Reserve storage fromReserve = reserves[_fromReserveToken];
        Reserve storage toReserve = reserves[_toReserveToken];
        require(fromReserve.isSaleEnabled); // validate input

        IBancorFormula formula = IBancorFormula(addressOf(BANCOR_FORMULA));
        uint256 amount = formula.calculateCrossReserveReturn(
            getReserveBalance(_fromReserveToken), 
            fromReserve.ratio, 
            getReserveBalance(_toReserveToken), 
            toReserve.ratio, 
            _amount);
        uint256 finalAmount = getFinalAmount(amount, 2);

        // return the amount minus the conversion fee and the conversion fee
        // the fee is higher (magnitude = 2) since cross reserve conversion equals 2 conversions (from / to the smart token)
        return (finalAmount, amount - finalAmount);
    }

    /**
      * @dev converts a specific amount of _fromToken to _toToken
      * can only be called by the bancor network contract
      * 
      * @param _fromToken  ERC20 token to convert from
      * @param _toToken    ERC20 token to convert to
      * @param _amount     amount to convert, in fromToken
      * @param _minReturn  if the conversion results in an amount smaller than the minimum return - it is cancelled, must be nonzero
      * 
      * @return conversion return amount
    */
    function convertInternal(IERC20Token _fromToken, IERC20Token _toToken, uint256 _amount, uint256 _minReturn)
        public
        only(BANCOR_NETWORK)
        conversionsAllowed
        greaterThanZero(_minReturn)
        returns (uint256)
    {
        require(_fromToken != _toToken); // validate input

        // conversion between the token and one of its reserves
        if (_toToken == token)
            return buy(_fromToken, _amount, _minReturn);
        else if (_fromToken == token)
            return sell(_toToken, _amount, _minReturn);

        uint256 amount;
        uint256 feeAmount;

        // conversion between 2 reserves
        (amount, feeAmount) = getCrossReserveReturn(_fromToken, _toToken, _amount);
        // ensure the trade gives something in return and meets the minimum requested amount
        require(amount != 0 && amount >= _minReturn);

        // update the source token virtual balance if relevant
        Reserve storage fromReserve = reserves[_fromToken];
        if (fromReserve.isVirtualBalanceEnabled)
            fromReserve.virtualBalance = fromReserve.virtualBalance.add(_amount);

        // update the target token virtual balance if relevant
        Reserve storage toReserve = reserves[_toToken];
        if (toReserve.isVirtualBalanceEnabled)
            toReserve.virtualBalance = toReserve.virtualBalance.sub(amount);

        // ensure that the trade won't deplete the reserve balance
        uint256 toReserveBalance = getReserveBalance(_toToken);
        assert(amount < toReserveBalance);

        // transfer funds from the caller in the from reserve token
        ensureTransferFrom(_fromToken, msg.sender, this, _amount);
        // transfer funds to the caller in the to reserve token
        // the transfer might fail if virtual balance is enabled
        ensureTransferFrom(_toToken, this, msg.sender, amount);

        // dispatch the conversion event
        // the fee is higher (magnitude = 2) since cross reserve conversion equals 2 conversions (from / to the smart token)
        dispatchConversionEvent(_fromToken, _toToken, _amount, amount, feeAmount);

        // dispatch price data updates for the smart token / both reserves
        emit PriceDataUpdate(_fromToken, token.totalSupply(), _fromToken.balanceOf(this), fromReserve.ratio);
        emit PriceDataUpdate(_toToken, token.totalSupply(), _toToken.balanceOf(this), toReserve.ratio);
        return amount;
    }

    /**
      * @dev buys the token by depositing one of its reserve tokens
      * 
      * @param _reserveToken    reserve token contract address
      * @param _depositAmount   amount to deposit (in the reserve token)
      * @param _minReturn       if the conversion results in an amount smaller than the minimum return - it is cancelled, must be nonzero
      * 
      * @return buy return amount
    */
    function buy(IERC20Token _reserveToken, uint256 _depositAmount, uint256 _minReturn) internal returns (uint256) {
        uint256 amount;
        uint256 feeAmount;
        (amount, feeAmount) = getPurchaseReturn(_reserveToken, _depositAmount);
        // ensure the trade gives something in return and meets the minimum requested amount
        require(amount != 0 && amount >= _minReturn);

        // update virtual balance if relevant
        Reserve storage reserve = reserves[_reserveToken];
        if (reserve.isVirtualBalanceEnabled)
            reserve.virtualBalance = reserve.virtualBalance.add(_depositAmount);

        // transfer funds from the caller in the reserve token
        ensureTransferFrom(_reserveToken, msg.sender, this, _depositAmount);
        // issue new funds to the caller in the smart token
        token.issue(msg.sender, amount);

        // dispatch the conversion event
        dispatchConversionEvent(_reserveToken, token, _depositAmount, amount, feeAmount);

        // dispatch price data update for the smart token/reserve
        emit PriceDataUpdate(_reserveToken, token.totalSupply(), _reserveToken.balanceOf(this), reserve.ratio);
        return amount;
    }

    /**
      * @dev sells the token by withdrawing from one of its reserve tokens
      * 
      * @param _reserveToken    reserve token contract address
      * @param _sellAmount      amount to sell (in the smart token)
      * @param _minReturn       if the conversion results in an amount smaller the minimum return - it is cancelled, must be nonzero
      * 
      * @return sell return amount
    */
    function sell(IERC20Token _reserveToken, uint256 _sellAmount, uint256 _minReturn) internal returns (uint256) {
        require(_sellAmount <= token.balanceOf(msg.sender)); // validate input
        uint256 amount;
        uint256 feeAmount;
        (amount, feeAmount) = getSaleReturn(_reserveToken, _sellAmount);
        // ensure the trade gives something in return and meets the minimum requested amount
        require(amount != 0 && amount >= _minReturn);

        // ensure that the trade will only deplete the reserve balance if the total supply is depleted as well
        uint256 tokenSupply = token.totalSupply();
        uint256 reserveBalance = _reserveToken.balanceOf(this);
        assert(amount < reserveBalance || (amount == reserveBalance && _sellAmount == tokenSupply));

        // update virtual balance if relevant
        Reserve storage reserve = reserves[_reserveToken];
        if (reserve.isVirtualBalanceEnabled)
            reserve.virtualBalance = reserve.virtualBalance.sub(amount);

        // destroy _sellAmount from the caller's balance in the smart token
        token.destroy(msg.sender, _sellAmount);
        // transfer funds to the caller in the reserve token
        ensureTransferFrom(_reserveToken, this, msg.sender, amount);

        // dispatch the conversion event
        dispatchConversionEvent(token, _reserveToken, _sellAmount, amount, feeAmount);

        // dispatch price data update for the smart token/reserve
        emit PriceDataUpdate(_reserveToken, token.totalSupply(), _reserveToken.balanceOf(this), reserve.ratio);
        return amount;
    }

    /**
      * @dev converts a specific amount of _fromToken to _toToken
      * note that prior to version 16, you should use 'convert' instead
      * 
      * @param _fromToken           ERC20 token to convert from
      * @param _toToken             ERC20 token to convert to
      * @param _amount              amount to convert, in fromToken
      * @param _minReturn           if the conversion results in an amount smaller than the minimum return - it is cancelled, must be nonzero
      * @param _affiliateAccount    affiliate account
      * @param _affiliateFee        affiliate fee in PPM
      * 
      * @return conversion return amount
    */
    function convert2(IERC20Token _fromToken, IERC20Token _toToken, uint256 _amount, uint256 _minReturn, address _affiliateAccount, uint256 _affiliateFee) public returns (uint256) {
        IERC20Token[] memory path = new IERC20Token[](3);
        (path[0], path[1], path[2]) = (_fromToken, token, _toToken);
        return quickConvert2(path, _amount, _minReturn, _affiliateAccount, _affiliateFee);
    }

    /**
      * @dev converts the token to any other token in the bancor network by following a predefined conversion path
      * note that when converting from an ERC20 token (as opposed to a smart token), allowance must be set beforehand
      * note that prior to version 16, you should use 'quickConvert' instead
      * 
      * @param _path                conversion path, see conversion path format in the BancorNetwork contract
      * @param _amount              amount to convert from (in the initial source token)
      * @param _minReturn           if the conversion results in an amount smaller than the minimum return - it is cancelled, must be nonzero
      * @param _affiliateAccount    affiliate account
      * @param _affiliateFee        affiliate fee in PPM
      * 
      * @return tokens issued in return
    */
    function quickConvert2(IERC20Token[] _path, uint256 _amount, uint256 _minReturn, address _affiliateAccount, uint256 _affiliateFee)
        public
        payable
        returns (uint256)
    {
        return quickConvertPrioritized2(_path, _amount, _minReturn, getSignature(0x0, 0x0, 0x0, 0x0, 0x0), _affiliateAccount, _affiliateFee);
    }

    /**
      * @dev converts the token to any other token in the bancor network by following a predefined conversion path
      * note that when converting from an ERC20 token (as opposed to a smart token), allowance must be set beforehand
      * note that prior to version 16, you should use 'quickConvertPrioritized' instead
      * 
      * @param _path                conversion path, see conversion path format in the BancorNetwork contract
      * @param _amount              amount to convert from (in the initial source token)
      * @param _minReturn           if the conversion results in an amount smaller than the minimum return - it is cancelled, must be nonzero
      * @param _signature           an array of the following elements:
      *     [0] uint256             custom value that was signed for prioritized conversion; must be equal to _amount
      *     [1] uint256             if the current block exceeded the given parameter - it is cancelled
      *     [2] uint8               (signature[128:130]) associated with the signer address and helps to validate if the signature is legit
      *     [3] bytes32             (signature[0:64]) associated with the signer address and helps to validate if the signature is legit
      *     [4] bytes32             (signature[64:128]) associated with the signer address and helps to validate if the signature is legit
      * if the array is empty (length == 0), then the gas-price limit is verified instead of the signature
      * @param _affiliateAccount    affiliate account
      * @param _affiliateFee        affiliate fee in PPM
      * 
      * @return tokens issued in return
    */
    function quickConvertPrioritized2(IERC20Token[] _path, uint256 _amount, uint256 _minReturn, uint256[] memory _signature, address _affiliateAccount, uint256 _affiliateFee)
        public
        payable
        returns (uint256)
    {
        require(_signature.length == 0 || _signature[0] == _amount);

        IBancorNetwork bancorNetwork = IBancorNetwork(addressOf(BANCOR_NETWORK));

        // we need to transfer the source tokens from the caller to the BancorNetwork contract,
        // so it can execute the conversion on behalf of the caller
        if (msg.value == 0) {
            // not ETH, send the source tokens to the BancorNetwork contract
            // if the token is the smart token, no allowance is required - destroy the tokens
            // from the caller and issue them to the BancorNetwork contract
            if (_path[0] == token) {
                token.destroy(msg.sender, _amount); // destroy _amount tokens from the caller's balance in the smart token
                token.issue(bancorNetwork, _amount); // issue _amount new tokens to the BancorNetwork contract
            } else {
                // otherwise, we assume we already have allowance, transfer the tokens directly to the BancorNetwork contract
                ensureTransferFrom(_path[0], msg.sender, bancorNetwork, _amount);
            }
        }

        // execute the conversion and pass on the ETH with the call
        return bancorNetwork.convertForPrioritized4.value(msg.value)(_path, _amount, _minReturn, msg.sender, _signature, _affiliateAccount, _affiliateFee);
    }

    /**
      * @dev allows a user to convert BNT that was sent from another blockchain into any other
      * token on the BancorNetwork without specifying the amount of BNT to be converted, but
      * rather by providing the xTransferId which allows us to get the amount from BancorX.
      * note that prior to version 16, you should use 'completeXConversion' instead
      * 
      * @param _path            conversion path, see conversion path format in the BancorNetwork contract
      * @param _minReturn       if the conversion results in an amount smaller than the minimum return - it is cancelled, must be nonzero
      * @param _conversionId    pre-determined unique (if non zero) id which refers to this transaction 
      * @param _signature       an array of the following elements:
      *     [0] uint256         custom value that was signed for prioritized conversion; must be equal to _conversionId
      *     [1] uint256         if the current block exceeded the given parameter - it is cancelled
      *     [2] uint8           (signature[128:130]) associated with the signer address and helps to validate if the signature is legit
      *     [3] bytes32         (signature[0:64]) associated with the signer address and helps to validate if the signature is legit
      *     [4] bytes32         (signature[64:128]) associated with the signer address and helps to validate if the signature is legit
      * if the array is empty (length == 0), then the gas-price limit is verified instead of the signature
      * 
      * @return tokens issued in return
    */
    function completeXConversion2(
        IERC20Token[] _path,
        uint256 _minReturn,
        uint256 _conversionId,
        uint256[] memory _signature
    )
        public
        returns (uint256)
    {
        // verify that the custom value (if valid) is equal to _conversionId
        require(_signature.length == 0 || _signature[0] == _conversionId);

        IBancorX bancorX = IBancorX(addressOf(BANCOR_X));
        IBancorNetwork bancorNetwork = IBancorNetwork(addressOf(BANCOR_NETWORK));

        // verify that the first token in the path is BNT
        require(_path[0] == addressOf(BNT_TOKEN));

        // get conversion amount from BancorX contract
        uint256 amount = bancorX.getXTransferAmount(_conversionId, msg.sender);

        // send BNT from msg.sender to the BancorNetwork contract
        token.destroy(msg.sender, amount);
        token.issue(bancorNetwork, amount);

        return bancorNetwork.convertForPrioritized4(_path, amount, _minReturn, msg.sender, _signature, address(0), 0);
    }

    /**
      * @dev returns whether or not the caller is an administrator
     */
    function isAdmin() internal view returns (bool) {
        return msg.sender == owner || msg.sender == manager;
    }

    /**
      * @dev ensures transfer of tokens, taking into account that some ERC-20 implementations don't return
      * true on success but revert on failure instead
      * 
      * @param _token     the token to transfer
      * @param _from      the address to transfer the tokens from
      * @param _to        the address to transfer the tokens to
      * @param _amount    the amount to transfer
    */
    function ensureTransferFrom(IERC20Token _token, address _from, address _to, uint256 _amount) private {
        // We must assume that functions `transfer` and `transferFrom` do not return anything,
        // because not all tokens abide the requirement of the ERC20 standard to return success or failure.
        // This is because in the current compiler version, the calling contract can handle more returned data than expected but not less.
        // This may change in the future, so that the calling contract will revert if the size of the data is not exactly what it expects.
        uint256 prevBalance = _token.balanceOf(_to);
        if (_from == address(this))
            INonStandardERC20(_token).transfer(_to, _amount);
        else
            INonStandardERC20(_token).transferFrom(_from, _to, _amount);
        uint256 postBalance = _token.balanceOf(_to);
        require(postBalance > prevBalance);
    }

    /**
      * @dev buys the token with all reserve tokens using the same percentage
      * for example, if the caller increases the supply by 10%,
      * then it will cost an amount equal to 10% of each reserve token balance
      * note that the function can be called only when conversions are enabled
      * 
      * @param _amount  amount to increase the supply by (in the smart token)
    */
    function fund(uint256 _amount)
        public
        conversionsAllowed
        multipleReservesOnly
    {
        uint256 supply = token.totalSupply();
        IBancorFormula formula = IBancorFormula(addressOf(BANCOR_FORMULA));

        // iterate through the reserve tokens and transfer a percentage equal to the ratio between _amount
        // and the total supply in each reserve from the caller to the converter
        IERC20Token reserveToken;
        uint256 reserveBalance;
        uint256 reserveAmount;
        for (uint16 i = 0; i < reserveTokens.length; i++) {
            reserveToken = reserveTokens[i];
            reserveBalance = reserveToken.balanceOf(this);
            reserveAmount = formula.calculateFundCost(supply, reserveBalance, totalReserveRatio, _amount);

            // update virtual balance if relevant
            Reserve storage reserve = reserves[reserveToken];
            if (reserve.isVirtualBalanceEnabled)
                reserve.virtualBalance = reserve.virtualBalance.add(reserveAmount);

            // transfer funds from the caller in the reserve token
            ensureTransferFrom(reserveToken, msg.sender, this, reserveAmount);

            // dispatch price data update for the smart token/reserve
            emit PriceDataUpdate(reserveToken, supply + _amount, reserveBalance + reserveAmount, reserve.ratio);
        }

        // issue new funds to the caller in the smart token
        token.issue(msg.sender, _amount);
    }

    /**
      * @dev sells the token for all reserve tokens using the same percentage
      * for example, if the holder sells 10% of the supply,
      * then they will receive 10% of each reserve token balance in return
      * note that the function can be called also when conversions are disabled
      * 
      * @param _amount  amount to liquidate (in the smart token)
    */
    function liquidate(uint256 _amount)
        public
        multipleReservesOnly
    {
        uint256 supply = token.totalSupply();
        IBancorFormula formula = IBancorFormula(addressOf(BANCOR_FORMULA));

        // destroy _amount from the caller's balance in the smart token
        token.destroy(msg.sender, _amount);

        // iterate through the reserve tokens and send a percentage equal to the ratio between _amount
        // and the total supply from each reserve balance to the caller
        IERC20Token reserveToken;
        uint256 reserveBalance;
        uint256 reserveAmount;
        for (uint16 i = 0; i < reserveTokens.length; i++) {
            reserveToken = reserveTokens[i];
            reserveBalance = reserveToken.balanceOf(this);
            reserveAmount = formula.calculateLiquidateReturn(supply, reserveBalance, totalReserveRatio, _amount);

            // update virtual balance if relevant
            Reserve storage reserve = reserves[reserveToken];
            if (reserve.isVirtualBalanceEnabled)
                reserve.virtualBalance = reserve.virtualBalance.sub(reserveAmount);

            // transfer funds to the caller in the reserve token
            ensureTransferFrom(reserveToken, this, msg.sender, reserveAmount);

            // dispatch price data update for the smart token/reserve
            emit PriceDataUpdate(reserveToken, supply - _amount, reserveBalance - reserveAmount, reserve.ratio);
        }
    }

    /**
      * @dev helper, dispatches the Conversion event
      * 
      * @param _fromToken       ERC20 token to convert from
      * @param _toToken         ERC20 token to convert to
      * @param _amount          amount purchased/sold (in the source token)
      * @param _returnAmount    amount returned (in the target token)
    */
    function dispatchConversionEvent(IERC20Token _fromToken, IERC20Token _toToken, uint256 _amount, uint256 _returnAmount, uint256 _feeAmount) private {
        // fee amount is converted to 255 bits -
        // negative amount means the fee is taken from the source token, positive amount means its taken from the target token
        // currently the fee is always taken from the target token
        // since we convert it to a signed number, we first ensure that it's capped at 255 bits to prevent overflow
        assert(_feeAmount < 2 ** 255);
        emit Conversion(_fromToken, _toToken, msg.sender, _amount, _returnAmount, int256(_feeAmount));
    }

    function getSignature(
        uint256 _customVal,
        uint256 _block,
        uint8 _v,
        bytes32 _r,
        bytes32 _s
    ) private pure returns (uint256[] memory) {
        if (_v == 0x0 && _r == 0x0 && _s == 0x0)
            return new uint256[](0);
        uint256[] memory signature = new uint256[](5);
        signature[0] = _customVal;
        signature[1] = _block;
        signature[2] = uint256(_v);
        signature[3] = uint256(_r);
        signature[4] = uint256(_s);
        return signature;
    }

    /**
      * @dev deprecated, backward compatibility
    */
    function change(IERC20Token _fromToken, IERC20Token _toToken, uint256 _amount, uint256 _minReturn) public returns (uint256) {
        return convertInternal(_fromToken, _toToken, _amount, _minReturn);
    }

    /**
      * @dev deprecated, backward compatibility
    */
    function convert(IERC20Token _fromToken, IERC20Token _toToken, uint256 _amount, uint256 _minReturn) public returns (uint256) {
        return convert2(_fromToken, _toToken, _amount, _minReturn, address(0), 0);
    }

    /**
      * @dev deprecated, backward compatibility
    */
    function quickConvert(IERC20Token[] _path, uint256 _amount, uint256 _minReturn) public payable returns (uint256) {
        return quickConvert2(_path, _amount, _minReturn, address(0), 0);
    }

    /**
      * @dev deprecated, backward compatibility
    */
    function quickConvertPrioritized(IERC20Token[] _path, uint256 _amount, uint256 _minReturn, uint256 _block, uint8 _v, bytes32 _r, bytes32 _s) public payable returns (uint256) {
        return quickConvertPrioritized2(_path, _amount, _minReturn, getSignature(_amount, _block, _v, _r, _s), address(0), 0);
    }

    /**
      * @dev deprecated, backward compatibility
    */
    function completeXConversion(IERC20Token[] _path, uint256 _minReturn, uint256 _conversionId, uint256 _block, uint8 _v, bytes32 _r, bytes32 _s) public returns (uint256) {
        return completeXConversion2(_path, _minReturn, _conversionId, getSignature(_conversionId, _block, _v, _r, _s));
    }

    /**
      * @dev deprecated, backward compatibility
    */
    function connectors(address _address) public view returns (uint256, uint32, bool, bool, bool) {
        Reserve storage reserve = reserves[_address];
        return(reserve.virtualBalance, reserve.ratio, reserve.isVirtualBalanceEnabled, reserve.isSaleEnabled, reserve.isSet);
    }

    /**
      * @dev deprecated, backward compatibility
    */
    function connectorTokens(uint256 _index) public view returns (IERC20Token) {
        return BancorConverter.reserveTokens[_index];
    }

    /**
      * @dev deprecated, backward compatibility
    */
    function connectorTokenCount() public view returns (uint16) {
        return reserveTokenCount();
    }

    /**
      * @dev deprecated, backward compatibility
    */
    function addConnector(IERC20Token _token, uint32 _weight, bool /*_enableVirtualBalance*/) public {
        addReserve(_token, _weight);
    }

    /**
      * @dev deprecated, backward compatibility
    */
    function updateConnector(IERC20Token _connectorToken, uint32 /*_weight*/, bool /*_enableVirtualBalance*/, uint256 _virtualBalance) public {
        updateReserveVirtualBalance(_connectorToken, _virtualBalance);
    }

    /**
      * @dev deprecated, backward compatibility
    */
    function disableConnectorSale(IERC20Token _connectorToken, bool _disable) public {
        disableReserveSale(_connectorToken, _disable);
    }

    /**
      * @dev deprecated, backward compatibility
    */
    function getConnectorBalance(IERC20Token _connectorToken) public view returns (uint256) {
        return getReserveBalance(_connectorToken);
    }

    /**
      * @dev deprecated, backward compatibility
    */
    function getCrossConnectorReturn(IERC20Token _fromConnectorToken, IERC20Token _toConnectorToken, uint256 _amount) public view returns (uint256, uint256) {
        return getCrossReserveReturn(_fromConnectorToken, _toConnectorToken, _amount);
    }
}

pragma solidity ^0.4.18;


/*
    Utilities & Common Modifiers
*/
contract Utils {
    /**
        constructor
    */
    function Utils() public {
    }

    // verifies that an amount is greater than zero
    modifier greaterThanZero(uint256 _amount) {
        require(_amount > 0);
        _;
    }

    // validates an address - currently only checks that it isn't null
    modifier validAddress(address _address) {
        require(_address != address(0));
        _;
    }

    // verifies that the address is different than this contract address
    modifier notThis(address _address) {
        require(_address != address(this));
        _;
    }

    // Overflow protected math functions

    /**
        @dev returns the sum of _x and _y, asserts if the calculation overflows

        @param _x   value 1
        @param _y   value 2

        @return sum
    */
    function safeAdd(uint256 _x, uint256 _y) internal pure returns (uint256) {
        uint256 z = _x + _y;
        assert(z >= _x);
        return z;
    }

    /**
        @dev returns the difference of _x minus _y, asserts if the subtraction results in a negative number

        @param _x   minuend
        @param _y   subtrahend

        @return difference
    */
    function safeSub(uint256 _x, uint256 _y) internal pure returns (uint256) {
        assert(_x >= _y);
        return _x - _y;
    }

    /**
        @dev returns the product of multiplying _x by _y, asserts if the calculation overflows

        @param _x   factor 1
        @param _y   factor 2

        @return product
    */
    function safeMul(uint256 _x, uint256 _y) internal pure returns (uint256) {
        uint256 z = _x * _y;
        assert(_x == 0 || z / _x == _y);
        return z;
    }
}


/*
    ERC20 Standard Token interface
*/
contract IERC20Token {
    // these functions aren't abstract since the compiler emits automatically generated getter functions as external
    function name() public view returns (string) {}
    function symbol() public view returns (string) {}
    function decimals() public view returns (uint8) {}
    function totalSupply() public view returns (uint256) {}
    function balanceOf(address _owner) public view returns (uint256) { _owner; }
    function allowance(address _owner, address _spender) public view returns (uint256) { _owner; _spender; }

    function transfer(address _to, uint256 _value) public returns (bool success);
    function transferFrom(address _from, address _to, uint256 _value) public returns (bool success);
    function approve(address _spender, uint256 _value) public returns (bool success);
}


/**
    ERC20 Standard Token implementation
*/
contract ERC20Token is IERC20Token, Utils {
    string public standard = 'Token 0.1';
    string public name = '';
    string public symbol = '';
    uint8 public decimals = 0;
    uint256 public totalSupply = 0;
    mapping (address => uint256) public balanceOf;
    mapping (address => mapping (address => uint256)) public allowance;

    event Transfer(address indexed _from, address indexed _to, uint256 _value);
    event Approval(address indexed _owner, address indexed _spender, uint256 _value);

    /**
        @dev constructor

        @param _name        token name
        @param _symbol      token symbol
        @param _decimals    decimal points, for display purposes
    */
    function ERC20Token(string _name, string _symbol, uint8 _decimals) public {
        require(bytes(_name).length > 0 && bytes(_symbol).length > 0); // validate input

        name = _name;
        symbol = _symbol;
        decimals = _decimals;
    }

    /**
        @dev send coins
        throws on any error rather then return a false flag to minimize user errors

        @param _to      target address
        @param _value   transfer amount

        @return true if the transfer was successful, false if it wasn't
    */
    function transfer(address _to, uint256 _value)
        public
        validAddress(_to)
        returns (bool success)
    {
        balanceOf[msg.sender] = safeSub(balanceOf[msg.sender], _value);
        balanceOf[_to] = safeAdd(balanceOf[_to], _value);
        Transfer(msg.sender, _to, _value);
        return true;
    }

    /**
        @dev an account/contract attempts to get the coins
        throws on any error rather then return a false flag to minimize user errors

        @param _from    source address
        @param _to      target address
        @param _value   transfer amount

        @return true if the transfer was successful, false if it wasn't
    */
    function transferFrom(address _from, address _to, uint256 _value)
        public
        validAddress(_from)
        validAddress(_to)
        returns (bool success)
    {
        allowance[_from][msg.sender] = safeSub(allowance[_from][msg.sender], _value);
        balanceOf[_from] = safeSub(balanceOf[_from], _value);
        balanceOf[_to] = safeAdd(balanceOf[_to], _value);
        Transfer(_from, _to, _value);
        return true;
    }

    /**
        @dev allow another account/contract to spend some tokens on your behalf
        throws on any error rather then return a false flag to minimize user errors

        also, to minimize the risk of the approve/transferFrom attack vector
        (see https://docs.google.com/document/d/1YLPtQxZu1UAvO9cZ1O2RPXBbT0mooh4DYKjA_jp-RLM/), approve has to be called twice
        in 2 separate transactions - once to change the allowance to 0 and secondly to change it to the new allowance value

        @param _spender approved address
        @param _value   allowance amount

        @return true if the approval was successful, false if it wasn't
    */
    function approve(address _spender, uint256 _value)
        public
        validAddress(_spender)
        returns (bool success)
    {
        // if the allowance isn't 0, it can only be updated to 0 to prevent an allowance change immediately after withdrawal
        require(_value == 0 || allowance[msg.sender][_spender] == 0);

        allowance[msg.sender][_spender] = _value;
        Approval(msg.sender, _spender, _value);
        return true;
    }
}


/*
    Owned contract interface
*/
contract IOwned {
    // this function isn't abstract since the compiler emits automatically generated getter functions as external
    function owner() public view returns (address) {}

    function transferOwnership(address _newOwner) public;
    function acceptOwnership() public;
}


/*
    Provides support and utilities for contract ownership
*/
contract Owned is IOwned {
    address public owner;
    address public newOwner;

    event OwnerUpdate(address indexed _prevOwner, address indexed _newOwner);

    /**
        @dev constructor
    */
    function Owned() public {
        owner = msg.sender;
    }

    // allows execution by the owner only
    modifier ownerOnly {
        assert(msg.sender == owner);
        _;
    }

    /**
        @dev allows transferring the contract ownership
        the new owner still needs to accept the transfer
        can only be called by the contract owner

        @param _newOwner    new contract owner
    */
    function transferOwnership(address _newOwner) public ownerOnly {
        require(_newOwner != owner);
        newOwner = _newOwner;
    }

    /**
        @dev used by a new owner to accept an ownership transfer
    */
    function acceptOwnership() public {
        require(msg.sender == newOwner);
        OwnerUpdate(owner, newOwner);
        owner = newOwner;
        newOwner = address(0);
    }
}


/*
    Token Holder interface
*/
contract ITokenHolder is IOwned {
    function withdrawTokens(IERC20Token _token, address _to, uint256 _amount) public;
}


/*
    We consider every contract to be a 'token holder' since it's currently not possible
    for a contract to deny receiving tokens.

    The TokenHolder's contract sole purpose is to provide a safety mechanism that allows
    the owner to send tokens that were sent to the contract by mistake back to their sender.
*/
contract TokenHolder is ITokenHolder, Owned, Utils {
    /**
        @dev constructor
    */
    function TokenHolder() public {
    }

    /**
        @dev withdraws tokens held by the contract and sends them to an account
        can only be called by the owner

        @param _token   ERC20 token contract address
        @param _to      account to receive the new amount
        @param _amount  amount to withdraw
    */
    function withdrawTokens(IERC20Token _token, address _to, uint256 _amount)
        public
        ownerOnly
        validAddress(_token)
        validAddress(_to)
        notThis(_to)
    {
        assert(_token.transfer(_to, _amount));
    }
}


/*
    Smart Token interface
*/
contract ISmartToken is IOwned, IERC20Token {
    function disableTransfers(bool _disable) public;
    function issue(address _to, uint256 _amount) public;
    function destroy(address _from, uint256 _amount) public;
}


/*
    Smart Token v0.3

    'Owned' is specified here for readability reasons
*/
contract SmartToken is ISmartToken, Owned, ERC20Token, TokenHolder {
    string public version = '0.3';

    bool public transfersEnabled = true;    // true if transfer/transferFrom are enabled, false if not

    // triggered when a smart token is deployed - the _token address is defined for forward compatibility, in case we want to trigger the event from a factory
    event NewSmartToken(address _token);
    // triggered when the total supply is increased
    event Issuance(uint256 _amount);
    // triggered when the total supply is decreased
    event Destruction(uint256 _amount);

    /**
        @dev constructor

        @param _name       token name
        @param _symbol     token short symbol, minimum 1 character
        @param _decimals   for display purposes only
    */
    function SmartToken(string _name, string _symbol, uint8 _decimals)
        public
        ERC20Token(_name, _symbol, _decimals)
    {
        NewSmartToken(address(this));
    }

    // allows execution only when transfers aren't disabled
    modifier transfersAllowed {
        assert(transfersEnabled);
        _;
    }

    /**
        @dev disables/enables transfers
        can only be called by the contract owner

        @param _disable    true to disable transfers, false to enable them
    */
    function disableTransfers(bool _disable) public ownerOnly {
        transfersEnabled = !_disable;
    }

    /**
        @dev increases the token supply and sends the new tokens to an account
        can only be called by the contract owner

        @param _to         account to receive the new amount
        @param _amount     amount to increase the supply by
    */
    function issue(address _to, uint256 _amount)
        public
        ownerOnly
        validAddress(_to)
        notThis(_to)
    {
        totalSupply = safeAdd(totalSupply, _amount);
        balanceOf[_to] = safeAdd(balanceOf[_to], _amount);

        Issuance(_amount);
        Transfer(this, _to, _amount);
    }

    /**
        @dev removes tokens from an account and decreases the token supply
        can be called by the contract owner to destroy tokens from any account or by any holder to destroy tokens from his/her own account

        @param _from       account to remove the amount from
        @param _amount     amount to decrease the supply by
    */
    function destroy(address _from, uint256 _amount) public {
        require(msg.sender == _from || msg.sender == owner); // validate input

        balanceOf[_from] = safeSub(balanceOf[_from], _amount);
        totalSupply = safeSub(totalSupply, _amount);

        Transfer(_from, this, _amount);
        Destruction(_amount);
    }

    // ERC20 standard method overrides with some extra functionality

    /**
        @dev send coins
        throws on any error rather then return a false flag to minimize user errors
        in addition to the standard checks, the function throws if transfers are disabled

        @param _to      target address
        @param _value   transfer amount

        @return true if the transfer was successful, false if it wasn't
    */
    function transfer(address _to, uint256 _value) public transfersAllowed returns (bool success) {
        assert(super.transfer(_to, _value));
        return true;
    }

    /**
        @dev an account/contract attempts to get the coins
        throws on any error rather then return a false flag to minimize user errors
        in addition to the standard checks, the function throws if transfers are disabled

        @param _from    source address
        @param _to      target address
        @param _value   transfer amount

        @return true if the transfer was successful, false if it wasn't
    */
    function transferFrom(address _from, address _to, uint256 _value) public transfersAllowed returns (bool success) {
        assert(super.transferFrom(_from, _to, _value));
        return true;
    }
}

pragma solidity ^0.4.21;

/*
    Owned contract interface
*/
contract IOwned {
    // this function isn't abstract since the compiler emits automatically generated getter functions as external
    function owner() public view returns (address) {}

    function transferOwnership(address _newOwner) public;
    function acceptOwnership() public;
}

/*
    ERC20 Standard Token interface
*/
contract IERC20Token {
    // these functions aren't abstract since the compiler emits automatically generated getter functions as external
    function name() public view returns (string) {}
    function symbol() public view returns (string) {}
    function decimals() public view returns (uint8) {}
    function totalSupply() public view returns (uint256) {}
    function balanceOf(address _owner) public view returns (uint256) { _owner; }
    function allowance(address _owner, address _spender) public view returns (uint256) { _owner; _spender; }

    function transfer(address _to, uint256 _value) public returns (bool success);
    function transferFrom(address _from, address _to, uint256 _value) public returns (bool success);
    function approve(address _spender, uint256 _value) public returns (bool success);
}

/*
    Smart Token interface
*/
contract ISmartToken is IOwned, IERC20Token {
    function disableTransfers(bool _disable) public;
    function issue(address _to, uint256 _amount) public;
    function destroy(address _from, uint256 _amount) public;
}

/*
    Contract Registry interface
*/
contract IContractRegistry {
    function getAddress(bytes32 _contractName) public view returns (address);
}

/*
    Contract Features interface
*/
contract IContractFeatures {
    function isSupported(address _contract, uint256 _features) public view returns (bool);
    function enableFeatures(uint256 _features, bool _enable) public;
}

/*
    Whitelist interface
*/
contract IWhitelist {
    function isWhitelisted(address _address) public view returns (bool);
}

/*
    Token Holder interface
*/
contract ITokenHolder is IOwned {
    function withdrawTokens(IERC20Token _token, address _to, uint256 _amount) public;
}

/*
    Bancor Formula interface
*/
contract IBancorFormula {
    function calculatePurchaseReturn(uint256 _supply, uint256 _connectorBalance, uint32 _connectorWeight, uint256 _depositAmount) public view returns (uint256);
    function calculateSaleReturn(uint256 _supply, uint256 _connectorBalance, uint32 _connectorWeight, uint256 _sellAmount) public view returns (uint256);
    function calculateCrossConnectorReturn(uint256 _fromConnectorBalance, uint32 _fromConnectorWeight, uint256 _toConnectorBalance, uint32 _toConnectorWeight, uint256 _amount) public view returns (uint256);
}

/*
    Bancor Converter interface
*/
contract IBancorConverter {
    function getReturn(IERC20Token _fromToken, IERC20Token _toToken, uint256 _amount) public view returns (uint256);
    function convert(IERC20Token _fromToken, IERC20Token _toToken, uint256 _amount, uint256 _minReturn) public returns (uint256);
    function conversionWhitelist() public view returns (IWhitelist) {}
    // deprecated, backward compatibility
    function change(IERC20Token _fromToken, IERC20Token _toToken, uint256 _amount, uint256 _minReturn) public returns (uint256);
}

/*
    Bancor Network interface
*/
contract IBancorNetwork {
    function convert(IERC20Token[] _path, uint256 _amount, uint256 _minReturn) public payable returns (uint256);
    function convertFor(IERC20Token[] _path, uint256 _amount, uint256 _minReturn, address _for) public payable returns (uint256);
    function convertForPrioritized2(
        IERC20Token[] _path,
        uint256 _amount,
        uint256 _minReturn,
        address _for,
        uint256 _block,
        uint8 _v,
        bytes32 _r,
        bytes32 _s)
        public payable returns (uint256);

    // deprecated, backward compatibility
    function convertForPrioritized(
        IERC20Token[] _path,
        uint256 _amount,
        uint256 _minReturn,
        address _for,
        uint256 _block,
        uint256 _nonce,
        uint8 _v,
        bytes32 _r,
        bytes32 _s)
        public payable returns (uint256);
}

/*
    Utilities & Common Modifiers
*/
contract Utils {
    /**
        constructor
    */
    function Utils() public {
    }

    // verifies that an amount is greater than zero
    modifier greaterThanZero(uint256 _amount) {
        require(_amount > 0);
        _;
    }

    // validates an address - currently only checks that it isn't null
    modifier validAddress(address _address) {
        require(_address != address(0));
        _;
    }

    // verifies that the address is different than this contract address
    modifier notThis(address _address) {
        require(_address != address(this));
        _;
    }

    // Overflow protected math functions

    /**
        @dev returns the sum of _x and _y, asserts if the calculation overflows

        @param _x   value 1
        @param _y   value 2

        @return sum
    */
    function safeAdd(uint256 _x, uint256 _y) internal pure returns (uint256) {
        uint256 z = _x + _y;
        assert(z >= _x);
        return z;
    }

    /**
        @dev returns the difference of _x minus _y, asserts if the subtraction results in a negative number

        @param _x   minuend
        @param _y   subtrahend

        @return difference
    */
    function safeSub(uint256 _x, uint256 _y) internal pure returns (uint256) {
        assert(_x >= _y);
        return _x - _y;
    }

    /**
        @dev returns the product of multiplying _x by _y, asserts if the calculation overflows

        @param _x   factor 1
        @param _y   factor 2

        @return product
    */
    function safeMul(uint256 _x, uint256 _y) internal pure returns (uint256) {
        uint256 z = _x * _y;
        assert(_x == 0 || z / _x == _y);
        return z;
    }
}

/*
    Provides support and utilities for contract ownership
*/
contract Owned is IOwned {
    address public owner;
    address public newOwner;

    event OwnerUpdate(address indexed _prevOwner, address indexed _newOwner);

    /**
        @dev constructor
    */
    function Owned() public {
        owner = msg.sender;
    }

    // allows execution by the owner only
    modifier ownerOnly {
        assert(msg.sender == owner);
        _;
    }

    /**
        @dev allows transferring the contract ownership
        the new owner still needs to accept the transfer
        can only be called by the contract owner

        @param _newOwner    new contract owner
    */
    function transferOwnership(address _newOwner) public ownerOnly {
        require(_newOwner != owner);
        newOwner = _newOwner;
    }

    /**
        @dev used by a new owner to accept an ownership transfer
    */
    function acceptOwnership() public {
        require(msg.sender == newOwner);
        emit OwnerUpdate(owner, newOwner);
        owner = newOwner;
        newOwner = address(0);
    }
}

/*
    Provides support and utilities for contract management
    Note that a managed contract must also have an owner
*/
contract Managed is Owned {
    address public manager;
    address public newManager;

    event ManagerUpdate(address indexed _prevManager, address indexed _newManager);

    /**
        @dev constructor
    */
    function Managed() public {
        manager = msg.sender;
    }

    // allows execution by the manager only
    modifier managerOnly {
        assert(msg.sender == manager);
        _;
    }

    // allows execution by either the owner or the manager only
    modifier ownerOrManagerOnly {
        require(msg.sender == owner || msg.sender == manager);
        _;
    }

    /**
        @dev allows transferring the contract management
        the new manager still needs to accept the transfer
        can only be called by the contract manager

        @param _newManager    new contract manager
    */
    function transferManagement(address _newManager) public ownerOrManagerOnly {
        require(_newManager != manager);
        newManager = _newManager;
    }

    /**
        @dev used by a new manager to accept a management transfer
    */
    function acceptManagement() public {
        require(msg.sender == newManager);
        emit ManagerUpdate(manager, newManager);
        manager = newManager;
        newManager = address(0);
    }
}

/**
    Id definitions for bancor contracts

    Can be used in conjunction with the contract registry to get contract addresses
*/
contract ContractIds {
    // generic
    bytes32 public constant CONTRACT_FEATURES = "ContractFeatures";

    // bancor logic
    bytes32 public constant BANCOR_NETWORK = "BancorNetwork";
    bytes32 public constant BANCOR_FORMULA = "BancorFormula";
    bytes32 public constant BANCOR_GAS_PRICE_LIMIT = "BancorGasPriceLimit";

    bytes32 public constant BANCOR_CONVERTER_FACTORY = "BancorConverterFactory";
    bytes32 public constant BANCOR_CONVERTER_UPGRADER = "BancorConverterUpgrader";

    // tokens
    bytes32 public constant BNT_TOKEN = "BNTToken";
}

/**
    Id definitions for bancor contract features

    Can be used to query the ContractFeatures contract to check whether a certain feature is supported by a contract
*/
contract FeatureIds {
    // converter features
    uint256 public constant CONVERTER_CONVERSION_WHITELIST = 1 << 0;
}

/*
    We consider every contract to be a 'token holder' since it's currently not possible
    for a contract to deny receiving tokens.

    The TokenHolder's contract sole purpose is to provide a safety mechanism that allows
    the owner to send tokens that were sent to the contract by mistake back to their sender.
*/
contract TokenHolder is ITokenHolder, Owned, Utils {
    /**
        @dev constructor
    */
    function TokenHolder() public {
    }

    /**
        @dev withdraws tokens held by the contract and sends them to an account
        can only be called by the owner

        @param _token   ERC20 token contract address
        @param _to      account to receive the new amount
        @param _amount  amount to withdraw
    */
    function withdrawTokens(IERC20Token _token, address _to, uint256 _amount)
        public
        ownerOnly
        validAddress(_token)
        validAddress(_to)
        notThis(_to)
    {
        assert(_token.transfer(_to, _amount));
    }
}

/*
    The smart token controller is an upgradable part of the smart token that allows
    more functionality as well as fixes for bugs/exploits.
    Once it accepts ownership of the token, it becomes the token's sole controller
    that can execute any of its functions.

    To upgrade the controller, ownership must be transferred to a new controller, along with
    any relevant data.

    The smart token must be set on construction and cannot be changed afterwards.
    Wrappers are provided (as opposed to a single 'execute' function) for each of the token's functions, for easier access.

    Note that the controller can transfer token ownership to a new controller that
    doesn't allow executing any function on the token, for a trustless solution.
    Doing that will also remove the owner's ability to upgrade the controller.
*/
contract SmartTokenController is TokenHolder {
    ISmartToken public token;   // smart token

    /**
        @dev constructor
    */
    function SmartTokenController(ISmartToken _token)
        public
        validAddress(_token)
    {
        token = _token;
    }

    // ensures that the controller is the token's owner
    modifier active() {
        assert(token.owner() == address(this));
        _;
    }

    // ensures that the controller is not the token's owner
    modifier inactive() {
        assert(token.owner() != address(this));
        _;
    }

    /**
        @dev allows transferring the token ownership
        the new owner still need to accept the transfer
        can only be called by the contract owner

        @param _newOwner    new token owner
    */
    function transferTokenOwnership(address _newOwner) public ownerOnly {
        token.transferOwnership(_newOwner);
    }

    /**
        @dev used by a new owner to accept a token ownership transfer
        can only be called by the contract owner
    */
    function acceptTokenOwnership() public ownerOnly {
        token.acceptOwnership();
    }

    /**
        @dev disables/enables token transfers
        can only be called by the contract owner

        @param _disable    true to disable transfers, false to enable them
    */
    function disableTokenTransfers(bool _disable) public ownerOnly {
        token.disableTransfers(_disable);
    }

    /**
        @dev withdraws tokens held by the controller and sends them to an account
        can only be called by the owner

        @param _token   ERC20 token contract address
        @param _to      account to receive the new amount
        @param _amount  amount to withdraw
    */
    function withdrawFromToken(
        IERC20Token _token, 
        address _to, 
        uint256 _amount
    ) 
        public
        ownerOnly
    {
        ITokenHolder(token).withdrawTokens(_token, _to, _amount);
    }
}

/*
    Bancor Converter v0.9

    The Bancor version of the token converter, allows conversion between a smart token and other ERC20 tokens and between different ERC20 tokens and themselves.

    ERC20 connector balance can be virtual, meaning that the calculations are based on the virtual balance instead of relying on
    the actual connector balance. This is a security mechanism that prevents the need to keep a very large (and valuable) balance in a single contract.

    The converter is upgradable (just like any SmartTokenController).

    WARNING: It is NOT RECOMMENDED to use the converter with Smart Tokens that have less than 8 decimal digits
             or with very small numbers because of precision loss

    Open issues:
    - Front-running attacks are currently mitigated by the following mechanisms:
        - minimum return argument for each conversion provides a way to define a minimum/maximum price for the transaction
        - gas price limit prevents users from having control over the order of execution
        - gas price limit check can be skipped if the transaction comes from a trusted, whitelisted signer
      Other potential solutions might include a commit/reveal based schemes
    - Possibly add getters for the connector fields so that the client won't need to rely on the order in the struct
*/
contract BancorConverter is IBancorConverter, SmartTokenController, Managed, ContractIds, FeatureIds {
    uint32 private constant MAX_WEIGHT = 1000000;
    uint64 private constant MAX_CONVERSION_FEE = 1000000;

    struct Connector {
        uint256 virtualBalance;         // connector virtual balance
        uint32 weight;                  // connector weight, represented in ppm, 1-1000000
        bool isVirtualBalanceEnabled;   // true if virtual balance is enabled, false if not
        bool isPurchaseEnabled;         // is purchase of the smart token enabled with the connector, can be set by the owner
        bool isSet;                     // used to tell if the mapping element is defined
    }

    string public version = '0.9';
    string public converterType = 'bancor';

    IContractRegistry public registry;                  // contract registry contract
    IWhitelist public conversionWhitelist;              // whitelist contract with list of addresses that are allowed to use the converter
    IERC20Token[] public connectorTokens;               // ERC20 standard token addresses
    IERC20Token[] public quickBuyPath;                  // conversion path that's used in order to buy the token with ETH
    mapping (address => Connector) public connectors;   // connector token addresses -> connector data
    uint32 private totalConnectorWeight = 0;            // used to efficiently prevent increasing the total connector weight above 100%
    uint32 public maxConversionFee = 0;                 // maximum conversion fee for the lifetime of the contract,
                                                        // represented in ppm, 0...1000000 (0 = no fee, 100 = 0.01%, 1000000 = 100%)
    uint32 public conversionFee = 0;                    // current conversion fee, represented in ppm, 0...maxConversionFee
    bool public conversionsEnabled = true;              // true if token conversions is enabled, false if not
    IERC20Token[] private convertPath;

    // triggered when a conversion between two tokens occurs
    event Conversion(
        address indexed _fromToken,
        address indexed _toToken,
        address indexed _trader,
        uint256 _amount,
        uint256 _return,
        int256 _conversionFee
    );
    // triggered after a conversion with new price data
    event PriceDataUpdate(
        address indexed _connectorToken,
        uint256 _tokenSupply,
        uint256 _connectorBalance,
        uint32 _connectorWeight
    );
    // triggered when the conversion fee is updated
    event ConversionFeeUpdate(uint32 _prevFee, uint32 _newFee);

    /**
        @dev constructor

        @param  _token              smart token governed by the converter
        @param  _registry           address of a contract registry contract
        @param  _maxConversionFee   maximum conversion fee, represented in ppm
        @param  _connectorToken     optional, initial connector, allows defining the first connector at deployment time
        @param  _connectorWeight    optional, weight for the initial connector
    */
    function BancorConverter(
        ISmartToken _token,
        IContractRegistry _registry,
        uint32 _maxConversionFee,
        IERC20Token _connectorToken,
        uint32 _connectorWeight
    )
        public
        SmartTokenController(_token)
        validAddress(_registry)
        validMaxConversionFee(_maxConversionFee)
    {
        registry = _registry;
        IContractFeatures features = IContractFeatures(registry.getAddress(ContractIds.CONTRACT_FEATURES));

        // initialize supported features
        if (features != address(0))
            features.enableFeatures(FeatureIds.CONVERTER_CONVERSION_WHITELIST, true);

        maxConversionFee = _maxConversionFee;

        if (_connectorToken != address(0))
            addConnector(_connectorToken, _connectorWeight, false);
    }

    // validates a connector token address - verifies that the address belongs to one of the connector tokens
    modifier validConnector(IERC20Token _address) {
        require(connectors[_address].isSet);
        _;
    }

    // validates a token address - verifies that the address belongs to one of the convertible tokens
    modifier validToken(IERC20Token _address) {
        require(_address == token || connectors[_address].isSet);
        _;
    }

    // validates maximum conversion fee
    modifier validMaxConversionFee(uint32 _conversionFee) {
        require(_conversionFee >= 0 && _conversionFee <= MAX_CONVERSION_FEE);
        _;
    }

    // validates conversion fee
    modifier validConversionFee(uint32 _conversionFee) {
        require(_conversionFee >= 0 && _conversionFee <= maxConversionFee);
        _;
    }

    // validates connector weight range
    modifier validConnectorWeight(uint32 _weight) {
        require(_weight > 0 && _weight <= MAX_WEIGHT);
        _;
    }

    // validates a conversion path - verifies that the number of elements is odd and that maximum number of 'hops' is 10
    modifier validConversionPath(IERC20Token[] _path) {
        require(_path.length > 2 && _path.length <= (1 + 2 * 10) && _path.length % 2 == 1);
        _;
    }

    // allows execution only when conversions aren't disabled
    modifier conversionsAllowed {
        assert(conversionsEnabled);
        _;
    }

    // allows execution by the BancorNetwork contract only
    modifier bancorNetworkOnly {
        IBancorNetwork bancorNetwork = IBancorNetwork(registry.getAddress(ContractIds.BANCOR_NETWORK));
        require(msg.sender == address(bancorNetwork));
        _;
    }

    /**
        @dev returns the number of connector tokens defined

        @return number of connector tokens
    */
    function connectorTokenCount() public view returns (uint16) {
        return uint16(connectorTokens.length);
    }

    /*
        @dev allows the owner to update the registry contract address

        @param _registry    address of a bancor converter registry contract
    */
    function setRegistry(IContractRegistry _registry)
        public
        ownerOnly
        validAddress(_registry)
        notThis(_registry)
    {
        registry = _registry;
    }

    /*
        @dev allows the owner to update & enable the conversion whitelist contract address
        when set, only addresses that are whitelisted are actually allowed to use the converter
        note that the whitelist check is actually done by the BancorNetwork contract

        @param _whitelist    address of a whitelist contract
    */
    function setConversionWhitelist(IWhitelist _whitelist)
        public
        ownerOnly
        notThis(_whitelist)
    {
        conversionWhitelist = _whitelist;
    }

    /*
        @dev allows the manager to update the quick buy path

        @param _path    new quick buy path, see conversion path format in the bancorNetwork contract
    */
    function setQuickBuyPath(IERC20Token[] _path)
        public
        ownerOnly
        validConversionPath(_path)
    {
        quickBuyPath = _path;
    }

    /*
        @dev allows the manager to clear the quick buy path
    */
    function clearQuickBuyPath() public ownerOnly {
        quickBuyPath.length = 0;
    }

    /**
        @dev returns the length of the quick buy path array

        @return quick buy path length
    */
    function getQuickBuyPathLength() public view returns (uint256) {
        return quickBuyPath.length;
    }

    /**
        @dev disables the entire conversion functionality
        this is a safety mechanism in case of a emergency
        can only be called by the manager

        @param _disable true to disable conversions, false to re-enable them
    */
    function disableConversions(bool _disable) public ownerOrManagerOnly {
        conversionsEnabled = !_disable;
    }

    /**
        @dev updates the current conversion fee
        can only be called by the manager

        @param _conversionFee new conversion fee, represented in ppm
    */
    function setConversionFee(uint32 _conversionFee)
        public
        ownerOrManagerOnly
        validConversionFee(_conversionFee)
    {
        emit ConversionFeeUpdate(conversionFee, _conversionFee);
        conversionFee = _conversionFee;
    }

    /*
        @dev given a return amount, returns the amount minus the conversion fee

        @param _amount      return amount
        @param _magnitude   1 for standard conversion, 2 for cross connector conversion

        @return return amount minus conversion fee
    */
    function getFinalAmount(uint256 _amount, uint8 _magnitude) public view returns (uint256) {
        return safeMul(_amount, (MAX_CONVERSION_FEE - conversionFee) ** _magnitude) / MAX_CONVERSION_FEE ** _magnitude;
    }

    /**
        @dev defines a new connector for the token
        can only be called by the owner while the converter is inactive

        @param _token                  address of the connector token
        @param _weight                 constant connector weight, represented in ppm, 1-1000000
        @param _enableVirtualBalance   true to enable virtual balance for the connector, false to disable it
    */
    function addConnector(IERC20Token _token, uint32 _weight, bool _enableVirtualBalance)
        public
        ownerOnly
        inactive
        validAddress(_token)
        notThis(_token)
        validConnectorWeight(_weight)
    {
        require(_token != token && !connectors[_token].isSet && totalConnectorWeight + _weight <= MAX_WEIGHT); // validate input

        connectors[_token].virtualBalance = 0;
        connectors[_token].weight = _weight;
        connectors[_token].isVirtualBalanceEnabled = _enableVirtualBalance;
        connectors[_token].isPurchaseEnabled = true;
        connectors[_token].isSet = true;
        connectorTokens.push(_token);
        totalConnectorWeight += _weight;
    }

    /**
        @dev updates one of the token connectors
        can only be called by the owner

        @param _connectorToken         address of the connector token
        @param _weight                 constant connector weight, represented in ppm, 1-1000000
        @param _enableVirtualBalance   true to enable virtual balance for the connector, false to disable it
        @param _virtualBalance         new connector's virtual balance
    */
    function updateConnector(IERC20Token _connectorToken, uint32 _weight, bool _enableVirtualBalance, uint256 _virtualBalance)
        public
        ownerOnly
        validConnector(_connectorToken)
        validConnectorWeight(_weight)
    {
        Connector storage connector = connectors[_connectorToken];
        require(totalConnectorWeight - connector.weight + _weight <= MAX_WEIGHT); // validate input

        totalConnectorWeight = totalConnectorWeight - connector.weight + _weight;
        connector.weight = _weight;
        connector.isVirtualBalanceEnabled = _enableVirtualBalance;
        connector.virtualBalance = _virtualBalance;
    }

    /**
        @dev disables purchasing with the given connector token in case the connector token got compromised
        can only be called by the owner
        note that selling is still enabled regardless of this flag and it cannot be disabled by the owner

        @param _connectorToken  connector token contract address
        @param _disable         true to disable the token, false to re-enable it
    */
    function disableConnectorPurchases(IERC20Token _connectorToken, bool _disable)
        public
        ownerOnly
        validConnector(_connectorToken)
    {
        connectors[_connectorToken].isPurchaseEnabled = !_disable;
    }

    /**
        @dev returns the connector's virtual balance if one is defined, otherwise returns the actual balance

        @param _connectorToken  connector token contract address

        @return connector balance
    */
    function getConnectorBalance(IERC20Token _connectorToken)
        public
        view
        validConnector(_connectorToken)
        returns (uint256)
    {
        Connector storage connector = connectors[_connectorToken];
        return connector.isVirtualBalanceEnabled ? connector.virtualBalance : _connectorToken.balanceOf(this);
    }

    /**
        @dev returns the expected return for converting a specific amount of _fromToken to _toToken

        @param _fromToken  ERC20 token to convert from
        @param _toToken    ERC20 token to convert to
        @param _amount     amount to convert, in fromToken

        @return expected conversion return amount
    */
    function getReturn(IERC20Token _fromToken, IERC20Token _toToken, uint256 _amount) public view returns (uint256) {
        require(_fromToken != _toToken); // validate input

        // conversion between the token and one of its connectors
        if (_toToken == token)
            return getPurchaseReturn(_fromToken, _amount);
        else if (_fromToken == token)
            return getSaleReturn(_toToken, _amount);

        // conversion between 2 connectors
        return getCrossConnectorReturn(_fromToken, _toToken, _amount);
    }

    /**
        @dev returns the expected return for buying the token for a connector token

        @param _connectorToken  connector token contract address
        @param _depositAmount   amount to deposit (in the connector token)

        @return expected purchase return amount
    */
    function getPurchaseReturn(IERC20Token _connectorToken, uint256 _depositAmount)
        public
        view
        active
        validConnector(_connectorToken)
        returns (uint256)
    {
        Connector storage connector = connectors[_connectorToken];
        require(connector.isPurchaseEnabled); // validate input

        uint256 tokenSupply = token.totalSupply();
        uint256 connectorBalance = getConnectorBalance(_connectorToken);
        IBancorFormula formula = IBancorFormula(registry.getAddress(ContractIds.BANCOR_FORMULA));
        uint256 amount = formula.calculatePurchaseReturn(tokenSupply, connectorBalance, connector.weight, _depositAmount);

        // return the amount minus the conversion fee
        return getFinalAmount(amount, 1);
    }

    /**
        @dev returns the expected return for selling the token for one of its connector tokens

        @param _connectorToken  connector token contract address
        @param _sellAmount      amount to sell (in the smart token)

        @return expected sale return amount
    */
    function getSaleReturn(IERC20Token _connectorToken, uint256 _sellAmount)
        public
        view
        active
        validConnector(_connectorToken)
        returns (uint256)
    {
        Connector storage connector = connectors[_connectorToken];
        uint256 tokenSupply = token.totalSupply();
        uint256 connectorBalance = getConnectorBalance(_connectorToken);
        IBancorFormula formula = IBancorFormula(registry.getAddress(ContractIds.BANCOR_FORMULA));
        uint256 amount = formula.calculateSaleReturn(tokenSupply, connectorBalance, connector.weight, _sellAmount);

        // return the amount minus the conversion fee
        return getFinalAmount(amount, 1);
    }

    /**
        @dev returns the expected return for selling one of the connector tokens for another connector token

        @param _fromConnectorToken  contract address of the connector token to convert from
        @param _toConnectorToken    contract address of the connector token to convert to
        @param _sellAmount          amount to sell (in the from connector token)

        @return expected sale return amount (in the to connector token)
    */
    function getCrossConnectorReturn(IERC20Token _fromConnectorToken, IERC20Token _toConnectorToken, uint256 _sellAmount)
        public
        view
        active
        validConnector(_fromConnectorToken)
        validConnector(_toConnectorToken)
        returns (uint256)
    {
        Connector storage fromConnector = connectors[_fromConnectorToken];
        Connector storage toConnector = connectors[_toConnectorToken];
        require(toConnector.isPurchaseEnabled); // validate input

        uint256 fromConnectorBalance = getConnectorBalance(_fromConnectorToken);
        uint256 toConnectorBalance = getConnectorBalance(_toConnectorToken);

        IBancorFormula formula = IBancorFormula(registry.getAddress(ContractIds.BANCOR_FORMULA));
        uint256 amount = formula.calculateCrossConnectorReturn(fromConnectorBalance, fromConnector.weight, toConnectorBalance, toConnector.weight, _sellAmount);

        // return the amount minus the conversion fee
        // the fee is higher (magnitude = 2) since cross connector conversion equals 2 conversions (from / to the smart token)
        return getFinalAmount(amount, 2);
    }

    /**
        @dev converts a specific amount of _fromToken to _toToken

        @param _fromToken  ERC20 token to convert from
        @param _toToken    ERC20 token to convert to
        @param _amount     amount to convert, in fromToken
        @param _minReturn  if the conversion results in an amount smaller than the minimum return - it is cancelled, must be nonzero

        @return conversion return amount
    */
    function convertInternal(IERC20Token _fromToken, IERC20Token _toToken, uint256 _amount, uint256 _minReturn)
        public
        bancorNetworkOnly
        conversionsAllowed
        greaterThanZero(_minReturn)
        returns (uint256)
    {
        require(_fromToken != _toToken); // validate input

        // conversion between the token and one of its connectors
        if (_toToken == token)
            return buy(_fromToken, _amount, _minReturn);
        else if (_fromToken == token)
            return sell(_toToken, _amount, _minReturn);

        // conversion between 2 connectors
        uint256 amount = getCrossConnectorReturn(_fromToken, _toToken, _amount);
        // ensure the trade gives something in return and meets the minimum requested amount
        require(amount != 0 && amount >= _minReturn);

        // update the source token virtual balance if relevant
        Connector storage fromConnector = connectors[_fromToken];
        if (fromConnector.isVirtualBalanceEnabled)
            fromConnector.virtualBalance = safeAdd(fromConnector.virtualBalance, _amount);

        // update the target token virtual balance if relevant
        Connector storage toConnector = connectors[_toToken];
        if (toConnector.isVirtualBalanceEnabled)
            toConnector.virtualBalance = safeSub(toConnector.virtualBalance, amount);

        // ensure that the trade won't deplete the connector balance
        uint256 toConnectorBalance = getConnectorBalance(_toToken);
        assert(amount < toConnectorBalance);

        // transfer funds from the caller in the from connector token
        assert(_fromToken.transferFrom(msg.sender, this, _amount));
        // transfer funds to the caller in the to connector token
        // the transfer might fail if the actual connector balance is smaller than the virtual balance
        assert(_toToken.transfer(msg.sender, amount));

        // calculate conversion fee and dispatch the conversion event
        // the fee is higher (magnitude = 2) since cross connector conversion equals 2 conversions (from / to the smart token)
        uint256 feeAmount = safeSub(amount, getFinalAmount(amount, 2));
        dispatchConversionEvent(_fromToken, _toToken, _amount, amount, feeAmount);

        // dispatch price data updates for the smart token / both connectors
        emit PriceDataUpdate(_fromToken, token.totalSupply(), getConnectorBalance(_fromToken), fromConnector.weight);
        emit PriceDataUpdate(_toToken, token.totalSupply(), getConnectorBalance(_toToken), toConnector.weight);
        return amount;
    }

    /**
        @dev converts a specific amount of _fromToken to _toToken

        @param _fromToken  ERC20 token to convert from
        @param _toToken    ERC20 token to convert to
        @param _amount     amount to convert, in fromToken
        @param _minReturn  if the conversion results in an amount smaller than the minimum return - it is cancelled, must be nonzero

        @return conversion return amount
    */
    function convert(IERC20Token _fromToken, IERC20Token _toToken, uint256 _amount, uint256 _minReturn) public returns (uint256) {
        convertPath = [_fromToken, token, _toToken];
        return quickConvert(convertPath, _amount, _minReturn);
    }

    /**
        @dev buys the token by depositing one of its connector tokens

        @param _connectorToken  connector token contract address
        @param _depositAmount   amount to deposit (in the connector token)
        @param _minReturn       if the conversion results in an amount smaller than the minimum return - it is cancelled, must be nonzero

        @return buy return amount
    */
    function buy(IERC20Token _connectorToken, uint256 _depositAmount, uint256 _minReturn) internal returns (uint256) {
        uint256 amount = getPurchaseReturn(_connectorToken, _depositAmount);
        // ensure the trade gives something in return and meets the minimum requested amount
        require(amount != 0 && amount >= _minReturn);

        // update virtual balance if relevant
        Connector storage connector = connectors[_connectorToken];
        if (connector.isVirtualBalanceEnabled)
            connector.virtualBalance = safeAdd(connector.virtualBalance, _depositAmount);

        // transfer funds from the caller in the connector token
        assert(_connectorToken.transferFrom(msg.sender, this, _depositAmount));
        // issue new funds to the caller in the smart token
        token.issue(msg.sender, amount);

        // calculate conversion fee and dispatch the conversion event
        uint256 feeAmount = safeSub(amount, getFinalAmount(amount, 1));
        dispatchConversionEvent(_connectorToken, token, _depositAmount, amount, feeAmount);

        // dispatch price data update for the smart token/connector
        emit PriceDataUpdate(_connectorToken, token.totalSupply(), getConnectorBalance(_connectorToken), connector.weight);
        return amount;
    }

    /**
        @dev sells the token by withdrawing from one of its connector tokens

        @param _connectorToken  connector token contract address
        @param _sellAmount      amount to sell (in the smart token)
        @param _minReturn       if the conversion results in an amount smaller the minimum return - it is cancelled, must be nonzero

        @return sell return amount
    */
    function sell(IERC20Token _connectorToken, uint256 _sellAmount, uint256 _minReturn) internal returns (uint256) {
        require(_sellAmount <= token.balanceOf(msg.sender)); // validate input

        uint256 amount = getSaleReturn(_connectorToken, _sellAmount);
        // ensure the trade gives something in return and meets the minimum requested amount
        require(amount != 0 && amount >= _minReturn);

        // ensure that the trade will only deplete the connector balance if the total supply is depleted as well
        uint256 tokenSupply = token.totalSupply();
        uint256 connectorBalance = getConnectorBalance(_connectorToken);
        assert(amount < connectorBalance || (amount == connectorBalance && _sellAmount == tokenSupply));

        // update virtual balance if relevant
        Connector storage connector = connectors[_connectorToken];
        if (connector.isVirtualBalanceEnabled)
            connector.virtualBalance = safeSub(connector.virtualBalance, amount);

        // destroy _sellAmount from the caller's balance in the smart token
        token.destroy(msg.sender, _sellAmount);
        // transfer funds to the caller in the connector token
        // the transfer might fail if the actual connector balance is smaller than the virtual balance
        assert(_connectorToken.transfer(msg.sender, amount));

        // calculate conversion fee and dispatch the conversion event
        uint256 feeAmount = safeSub(amount, getFinalAmount(amount, 1));
        dispatchConversionEvent(token, _connectorToken, _sellAmount, amount, feeAmount);

        // dispatch price data update for the smart token/connector
        emit PriceDataUpdate(_connectorToken, token.totalSupply(), getConnectorBalance(_connectorToken), connector.weight);
        return amount;
    }

    /**
        @dev converts the token to any other token in the bancor network by following a predefined conversion path
        note that when converting from an ERC20 token (as opposed to a smart token), allowance must be set beforehand

        @param _path        conversion path, see conversion path format in the BancorNetwork contract
        @param _amount      amount to convert from (in the initial source token)
        @param _minReturn   if the conversion results in an amount smaller than the minimum return - it is cancelled, must be nonzero

        @return tokens issued in return
    */
    function quickConvert(IERC20Token[] _path, uint256 _amount, uint256 _minReturn)
        public
        payable
        validConversionPath(_path)
        returns (uint256)
    {
        return quickConvertPrioritized(_path, _amount, _minReturn, 0x0, 0x0, 0x0, 0x0);
    }

    /**
        @dev converts the token to any other token in the bancor network by following a predefined conversion path
        note that when converting from an ERC20 token (as opposed to a smart token), allowance must be set beforehand

        @param _path        conversion path, see conversion path format in the BancorNetwork contract
        @param _amount      amount to convert from (in the initial source token)
        @param _minReturn   if the conversion results in an amount smaller than the minimum return - it is cancelled, must be nonzero
        @param _block       if the current block exceeded the given parameter - it is cancelled
        @param _v           (signature[128:130]) associated with the signer address and helps validating if the signature is legit
        @param _r           (signature[0:64]) associated with the signer address and helps validating if the signature is legit
        @param _s           (signature[64:128]) associated with the signer address and helps validating if the signature is legit

        @return tokens issued in return
    */
    function quickConvertPrioritized(IERC20Token[] _path, uint256 _amount, uint256 _minReturn, uint256 _block, uint8 _v, bytes32 _r, bytes32 _s)
        public
        payable
        validConversionPath(_path)
        returns (uint256)
    {
        IERC20Token fromToken = _path[0];
        IBancorNetwork bancorNetwork = IBancorNetwork(registry.getAddress(ContractIds.BANCOR_NETWORK));

        // we need to transfer the source tokens from the caller to the BancorNetwork contract,
        // so it can execute the conversion on behalf of the caller
        if (msg.value == 0) {
            // not ETH, send the source tokens to the BancorNetwork contract
            // if the token is the smart token, no allowance is required - destroy the tokens
            // from the caller and issue them to the BancorNetwork contract
            if (fromToken == token) {
                token.destroy(msg.sender, _amount); // destroy _amount tokens from the caller's balance in the smart token
                token.issue(bancorNetwork, _amount); // issue _amount new tokens to the BancorNetwork contract
            } else {
                // otherwise, we assume we already have allowance, transfer the tokens directly to the BancorNetwork contract
                assert(fromToken.transferFrom(msg.sender, bancorNetwork, _amount));
            }
        }

        // execute the conversion and pass on the ETH with the call
        return bancorNetwork.convertForPrioritized2.value(msg.value)(_path, _amount, _minReturn, msg.sender, _block, _v, _r, _s);
    }

    // deprecated, backward compatibility
    function change(IERC20Token _fromToken, IERC20Token _toToken, uint256 _amount, uint256 _minReturn) public returns (uint256) {
        return convertInternal(_fromToken, _toToken, _amount, _minReturn);
    }

    /**
        @dev helper, dispatches the Conversion event

        @param _fromToken       ERC20 token to convert from
        @param _toToken         ERC20 token to convert to
        @param _amount          amount purchased/sold (in the source token)
        @param _returnAmount    amount returned (in the target token)
    */
    function dispatchConversionEvent(IERC20Token _fromToken, IERC20Token _toToken, uint256 _amount, uint256 _returnAmount, uint256 _feeAmount) private {
        // fee amount is converted to 255 bits -
        // negative amount means the fee is taken from the source token, positive amount means its taken from the target token
        // currently the fee is always taken from the target token
        // since we convert it to a signed number, we first ensure that it's capped at 255 bits to prevent overflow
        assert(_feeAmount <= 2 ** 255);
        emit Conversion(_fromToken, _toToken, msg.sender, _amount, _returnAmount, int256(_feeAmount));
    }

    /**
        @dev fallback, buys the smart token with ETH
        note that the purchase will use the price at the time of the purchase
    */
    function() payable public {
        quickConvert(quickBuyPath, msg.value, 1);
    }
}

pragma solidity ^0.4.18;


contract Utils {
    /**
        constructor
    */
    function Utils() public {
    }

    // verifies that an amount is greater than zero
    modifier greaterThanZero(uint256 _amount) {
        require(_amount > 0);
        _;
    }

    // validates an address - currently only checks that it isn't null
    modifier validAddress(address _address) {
        require(_address != address(0));
        _;
    }

    // verifies that the address is different than this contract address
    modifier notThis(address _address) {
        require(_address != address(this));
        _;
    }

    // Overflow protected math functions

    /**
        @dev returns the sum of _x and _y, asserts if the calculation overflows

        @param _x   value 1
        @param _y   value 2

        @return sum
    */
    function safeAdd(uint256 _x, uint256 _y) internal pure returns (uint256) {
        uint256 z = _x + _y;
        assert(z >= _x);
        return z;
    }

    /**
        @dev returns the difference of _x minus _y, asserts if the subtraction results in a negative number

        @param _x   minuend
        @param _y   subtrahend

        @return difference
    */
    function safeSub(uint256 _x, uint256 _y) internal pure returns (uint256) {
        assert(_x >= _y);
        return _x - _y;
    }

    /**
        @dev returns the product of multiplying _x by _y, asserts if the calculation overflows

        @param _x   factor 1
        @param _y   factor 2

        @return product
    */
    function safeMul(uint256 _x, uint256 _y) internal pure returns (uint256) {
        uint256 z = _x * _y;
        assert(_x == 0 || z / _x == _y);
        return z;
    }
}

contract IOwned {
    // this function isn't abstract since the compiler emits automatically generated getter functions as external
    function owner() public view returns (address) {}

    function transferOwnership(address _newOwner) public;
    function acceptOwnership() public;
}

contract Owned is IOwned {
    address public owner;
    address public newOwner;

    event OwnerUpdate(address indexed _prevOwner, address indexed _newOwner);

    /**
        @dev constructor
    */
    function Owned() public {
        owner = msg.sender;
    }

    // allows execution by the owner only
    modifier ownerOnly {
        assert(msg.sender == owner);
        _;
    }

    /**
        @dev allows transferring the contract ownership
        the new owner still needs to accept the transfer
        can only be called by the contract owner

        @param _newOwner    new contract owner
    */
    function transferOwnership(address _newOwner) public ownerOnly {
        require(_newOwner != owner);
        newOwner = _newOwner;
    }

    /**
        @dev used by a new owner to accept an ownership transfer
    */
    function acceptOwnership() public {
        require(msg.sender == newOwner);
        OwnerUpdate(owner, newOwner);
        owner = newOwner;
        newOwner = address(0);
    }
}



contract IBancorGasPriceLimit {
    function gasPrice() public view returns (uint256) {}
    function validateGasPrice(uint256) public view;
}


contract BancorGasPriceLimit is IBancorGasPriceLimit, Owned, Utils {
    uint256 public gasPrice = 0 wei;    // maximum gas price for bancor transactions
    
    /**
        @dev constructor

        @param _gasPrice    gas price limit
    */
    function BancorGasPriceLimit(uint256 _gasPrice)
        public
        greaterThanZero(_gasPrice)
    {
        gasPrice = _gasPrice;
    }

    /*
        @dev gas price getter

        @return the current gas price
    */
    function gasPrice() public view returns (uint256) {
        return gasPrice;
    }

    /*
        @dev allows the owner to update the gas price limit

        @param _gasPrice    new gas price limit
    */
    function setGasPrice(uint256 _gasPrice)
        public
        ownerOnly
        greaterThanZero(_gasPrice)
    {
        gasPrice = _gasPrice;
    }

    /*
        @dev validate that the given gas price is equal to the current network gas price

        @param _gasPrice    tested gas price
    */
    function validateGasPrice(uint256 _gasPrice)
        public
        view
        greaterThanZero(_gasPrice)
    {
        require(_gasPrice <= gasPrice);
    }
}

pragma solidity ^0.4.11;

/*
    Utilities & Common Modifiers
*/
contract Utils {
    /**
        constructor
    */
    function Utils() {
    }

    // verifies that an amount is greater than zero
    modifier greaterThanZero(uint256 _amount) {
        require(_amount > 0);
        _;
    }

    // validates an address - currently only checks that it isn't null
    modifier validAddress(address _address) {
        require(_address != 0x0);
        _;
    }

    // verifies that the address is different than this contract address
    modifier notThis(address _address) {
        require(_address != address(this));
        _;
    }

    // Overflow protected math functions

    /**
        @dev returns the sum of _x and _y, asserts if the calculation overflows

        @param _x   value 1
        @param _y   value 2

        @return sum
    */
    function safeAdd(uint256 _x, uint256 _y) internal returns (uint256) {
        uint256 z = _x + _y;
        assert(z >= _x);
        return z;
    }

    /**
        @dev returns the difference of _x minus _y, asserts if the subtraction results in a negative number

        @param _x   minuend
        @param _y   subtrahend

        @return difference
    */
    function safeSub(uint256 _x, uint256 _y) internal returns (uint256) {
        assert(_x >= _y);
        return _x - _y;
    }

    /**
        @dev returns the product of multiplying _x by _y, asserts if the calculation overflows

        @param _x   factor 1
        @param _y   factor 2

        @return product
    */
    function safeMul(uint256 _x, uint256 _y) internal returns (uint256) {
        uint256 z = _x * _y;
        assert(_x == 0 || z / _x == _y);
        return z;
    }
}

/*
    Owned contract interface
*/
contract IOwned {
    // this function isn't abstract since the compiler emits automatically generated getter functions as external
    function owner() public constant returns (address owner) { owner; }

    function transferOwnership(address _newOwner) public;
    function acceptOwnership() public;
}

/*
    Provides support and utilities for contract ownership
*/
contract Owned is IOwned {
    address public owner;
    address public newOwner;

    event OwnerUpdate(address _prevOwner, address _newOwner);

    /**
        @dev constructor
    */
    function Owned() {
        owner = msg.sender;
    }

    // allows execution by the owner only
    modifier ownerOnly {
        assert(msg.sender == owner);
        _;
    }

    /**
        @dev allows transferring the contract ownership
        the new owner still needs to accept the transfer
        can only be called by the contract owner

        @param _newOwner    new contract owner
    */
    function transferOwnership(address _newOwner) public ownerOnly {
        require(_newOwner != owner);
        newOwner = _newOwner;
    }

    /**
        @dev used by a new owner to accept an ownership transfer
    */
    function acceptOwnership() public {
        require(msg.sender == newOwner);
        OwnerUpdate(owner, newOwner);
        owner = newOwner;
        newOwner = 0x0;
    }
}

/*
    Token Holder interface
*/
contract ITokenHolder is IOwned {
    function withdrawTokens(IERC20Token _token, address _to, uint256 _amount) public;
}

/*
    We consider every contract to be a 'token holder' since it's currently not possible
    for a contract to deny receiving tokens.

    The TokenHolder's contract sole purpose is to provide a safety mechanism that allows
    the owner to send tokens that were sent to the contract by mistake back to their sender.
*/
contract TokenHolder is ITokenHolder, Owned, Utils {
    /**
        @dev constructor
    */
    function TokenHolder() {
    }

    /**
        @dev withdraws tokens held by the contract and sends them to an account
        can only be called by the owner

        @param _token   ERC20 token contract address
        @param _to      account to receive the new amount
        @param _amount  amount to withdraw
    */
    function withdrawTokens(IERC20Token _token, address _to, uint256 _amount)
        public
        ownerOnly
        validAddress(_token)
        validAddress(_to)
        notThis(_to)
    {
        assert(_token.transfer(_to, _amount));
    }
}

/*
    ERC20 Standard Token interface
*/
contract IERC20Token {
    // these functions aren't abstract since the compiler emits automatically generated getter functions as external
    function name() public constant returns (string name) { name; }
    function symbol() public constant returns (string symbol) { symbol; }
    function decimals() public constant returns (uint8 decimals) { decimals; }
    function totalSupply() public constant returns (uint256 totalSupply) { totalSupply; }
    function balanceOf(address _owner) public constant returns (uint256 balance) { _owner; balance; }
    function allowance(address _owner, address _spender) public constant returns (uint256 remaining) { _owner; _spender; remaining; }

    function transfer(address _to, uint256 _value) public returns (bool success);
    function transferFrom(address _from, address _to, uint256 _value) public returns (bool success);
    function approve(address _spender, uint256 _value) public returns (bool success);
}

/**
    ERC20 Standard Token implementation
*/
contract ERC20Token is IERC20Token, Utils {
    string public standard = 'Token 0.1';
    string public name = '';
    string public symbol = '';
    uint8 public decimals = 0;
    uint256 public totalSupply = 0;
    mapping (address => uint256) public balanceOf;
    mapping (address => mapping (address => uint256)) public allowance;

    event Transfer(address indexed _from, address indexed _to, uint256 _value);
    event Approval(address indexed _owner, address indexed _spender, uint256 _value);

    /**
        @dev constructor

        @param _name        token name
        @param _symbol      token symbol
        @param _decimals    decimal points, for display purposes
    */
    function ERC20Token(string _name, string _symbol, uint8 _decimals) {
        require(bytes(_name).length > 0 && bytes(_symbol).length > 0); // validate input

        name = _name;
        symbol = _symbol;
        decimals = _decimals;
    }

    /**
        @dev send coins
        throws on any error rather then return a false flag to minimize user errors

        @param _to      target address
        @param _value   transfer amount

        @return true if the transfer was successful, false if it wasn't
    */
    function transfer(address _to, uint256 _value)
        public
        validAddress(_to)
        returns (bool success)
    {
        balanceOf[msg.sender] = safeSub(balanceOf[msg.sender], _value);
        balanceOf[_to] = safeAdd(balanceOf[_to], _value);
        Transfer(msg.sender, _to, _value);
        return true;
    }

    /**
        @dev an account/contract attempts to get the coins
        throws on any error rather then return a false flag to minimize user errors

        @param _from    source address
        @param _to      target address
        @param _value   transfer amount

        @return true if the transfer was successful, false if it wasn't
    */
    function transferFrom(address _from, address _to, uint256 _value)
        public
        validAddress(_from)
        validAddress(_to)
        returns (bool success)
    {
        allowance[_from][msg.sender] = safeSub(allowance[_from][msg.sender], _value);
        balanceOf[_from] = safeSub(balanceOf[_from], _value);
        balanceOf[_to] = safeAdd(balanceOf[_to], _value);
        Transfer(_from, _to, _value);
        return true;
    }

    /**
        @dev allow another account/contract to spend some tokens on your behalf
        throws on any error rather then return a false flag to minimize user errors

        also, to minimize the risk of the approve/transferFrom attack vector
        (see https://docs.google.com/document/d/1YLPtQxZu1UAvO9cZ1O2RPXBbT0mooh4DYKjA_jp-RLM/), approve has to be called twice
        in 2 separate transactions - once to change the allowance to 0 and secondly to change it to the new allowance value

        @param _spender approved address
        @param _value   allowance amount

        @return true if the approval was successful, false if it wasn't
    */
    function approve(address _spender, uint256 _value)
        public
        validAddress(_spender)
        returns (bool success)
    {
        // if the allowance isn't 0, it can only be updated to 0 to prevent an allowance change immediately after withdrawal
        require(_value == 0 || allowance[msg.sender][_spender] == 0);

        allowance[msg.sender][_spender] = _value;
        Approval(msg.sender, _spender, _value);
        return true;
    }
}

/*
    Ether Token interface
*/
contract IEtherToken is ITokenHolder, IERC20Token {
    function deposit() public payable;
    function withdraw(uint256 _amount) public;
    function withdrawTo(address _to, uint256 _amount);
}

/**
    Ether tokenization contract

    'Owned' is specified here for readability reasons
*/
contract EtherToken is IEtherToken, Owned, ERC20Token, TokenHolder {
    // triggered when the total supply is increased
    event Issuance(uint256 _amount);
    // triggered when the total supply is decreased
    event Destruction(uint256 _amount);

    /**
        @dev constructor
    */
    function EtherToken()
        ERC20Token('Ether Token', 'ETH', 18) {
    }

    /**
        @dev deposit ether in the account
    */
    function deposit() public payable {
        balanceOf[msg.sender] = safeAdd(balanceOf[msg.sender], msg.value); // add the value to the account balance
        totalSupply = safeAdd(totalSupply, msg.value); // increase the total supply

        Issuance(msg.value);
        Transfer(this, msg.sender, msg.value);
    }

    /**
        @dev withdraw ether from the account

        @param _amount  amount of ether to withdraw
    */
    function withdraw(uint256 _amount) public {
        withdrawTo(msg.sender, _amount);
    }

    /**
        @dev withdraw ether from the account to a target account

        @param _to      account to receive the ether
        @param _amount  amount of ether to withdraw
    */
    function withdrawTo(address _to, uint256 _amount)
        public
        notThis(_to)
    {
        balanceOf[msg.sender] = safeSub(balanceOf[msg.sender], _amount); // deduct the amount from the account balance
        totalSupply = safeSub(totalSupply, _amount); // decrease the total supply
        _to.transfer(_amount); // send the amount to the target account

        Transfer(msg.sender, this, _amount);
        Destruction(_amount);
    }

    // ERC20 standard method overrides with some extra protection

    /**
        @dev send coins
        throws on any error rather then return a false flag to minimize user errors

        @param _to      target address
        @param _value   transfer amount

        @return true if the transfer was successful, false if it wasn't
    */
    function transfer(address _to, uint256 _value)
        public
        notThis(_to)
        returns (bool success)
    {
        assert(super.transfer(_to, _value));
        return true;
    }

    /**
        @dev an account/contract attempts to get the coins
        throws on any error rather then return a false flag to minimize user errors

        @param _from    source address
        @param _to      target address
        @param _value   transfer amount

        @return true if the transfer was successful, false if it wasn't
    */
    function transferFrom(address _from, address _to, uint256 _value)
        public
        notThis(_to)
        returns (bool success)
    {
        assert(super.transferFrom(_from, _to, _value));
        return true;
    }

    /**
        @dev deposit ether in the account
    */
    function() public payable {
        deposit();
    }
}

pragma solidity ^0.4.11;

/*
    Overflow protected math functions
*/
contract SafeMath {
    /**
        constructor
    */
    function SafeMath() {
    }

    /**
        @dev returns the sum of _x and _y, asserts if the calculation overflows

        @param _x   value 1
        @param _y   value 2

        @return sum
    */
    function safeAdd(uint256 _x, uint256 _y) internal returns (uint256) {
        uint256 z = _x + _y;
        assert(z >= _x);
        return z;
    }

    /**
        @dev returns the difference of _x minus _y, asserts if the subtraction results in a negative number

        @param _x   minuend
        @param _y   subtrahend

        @return difference
    */
    function safeSub(uint256 _x, uint256 _y) internal returns (uint256) {
        assert(_x >= _y);
        return _x - _y;
    }

    /**
        @dev returns the product of multiplying _x by _y, asserts if the calculation overflows

        @param _x   factor 1
        @param _y   factor 2

        @return product
    */
    function safeMul(uint256 _x, uint256 _y) internal returns (uint256) {
        uint256 z = _x * _y;
        assert(_x == 0 || z / _x == _y);
        return z;
    }
} 

/*
    Owned contract interface
*/
contract IOwned {
    // this function isn't abstract since the compiler emits automatically generated getter functions as external
    function owner() public constant returns (address owner) { owner; }

    function transferOwnership(address _newOwner) public;
    function acceptOwnership() public;
}

/*
    Provides support and utilities for contract ownership
*/
contract Owned is IOwned {
    address public owner;
    address public newOwner;

    event OwnerUpdate(address _prevOwner, address _newOwner);

    /**
        @dev constructor
    */
    function Owned() {
        owner = msg.sender;
    }

    // allows execution by the owner only
    modifier ownerOnly {
        assert(msg.sender == owner);
        _;
    }

    /**
        @dev allows transferring the contract ownership
        the new owner still need to accept the transfer
        can only be called by the contract owner

        @param _newOwner    new contract owner
    */
    function transferOwnership(address _newOwner) public ownerOnly {
        require(_newOwner != owner);
        newOwner = _newOwner;
    }

    /**
        @dev used by a new owner to accept an ownership transfer
    */
    function acceptOwnership() public {
        require(msg.sender == newOwner);
        OwnerUpdate(owner, newOwner);
        owner = newOwner;
        newOwner = 0x0;
    }
}

/*
    Token Holder interface
*/
contract ITokenHolder is IOwned {
    function withdrawTokens(IERC20Token _token, address _to, uint256 _amount) public;
}

/*
    We consider every contract to be a 'token holder' since it's currently not possible
    for a contract to deny receiving tokens.

    The TokenHolder's contract sole purpose is to provide a safety mechanism that allows
    the owner to send tokens that were sent to the contract by mistake back to their sender.
*/
contract TokenHolder is ITokenHolder, Owned {
    /**
        @dev constructor
    */
    function TokenHolder() {
    }

    // validates an address - currently only checks that it isn't null
    modifier validAddress(address _address) {
        require(_address != 0x0);
        _;
    }

    // verifies that the address is different than this contract address
    modifier notThis(address _address) {
        require(_address != address(this));
        _;
    }

    /**
        @dev withdraws tokens held by the contract and sends them to an account
        can only be called by the owner

        @param _token   ERC20 token contract address
        @param _to      account to receive the new amount
        @param _amount  amount to withdraw
    */
    function withdrawTokens(IERC20Token _token, address _to, uint256 _amount)
        public
        ownerOnly
        validAddress(_token)
        validAddress(_to)
        notThis(_to)
    {
        assert(_token.transfer(_to, _amount));
    }
}

/*
    ERC20 Standard Token interface
*/
contract IERC20Token {
    // these functions aren't abstract since the compiler emits automatically generated getter functions as external
    function name() public constant returns (string name) { name; }
    function symbol() public constant returns (string symbol) { symbol; }
    function decimals() public constant returns (uint8 decimals) { decimals; }
    function totalSupply() public constant returns (uint256 totalSupply) { totalSupply; }
    function balanceOf(address _owner) public constant returns (uint256 balance) { _owner; balance; }
    function allowance(address _owner, address _spender) public constant returns (uint256 remaining) { _owner; _spender; remaining; }

    function transfer(address _to, uint256 _value) public returns (bool success);
    function transferFrom(address _from, address _to, uint256 _value) public returns (bool success);
    function approve(address _spender, uint256 _value) public returns (bool success);
}

/**
    ERC20 Standard Token implementation
*/
contract ERC20Token is IERC20Token, SafeMath {
    string public standard = 'Token 0.1';
    string public name = '';
    string public symbol = '';
    uint8 public decimals = 0;
    uint256 public totalSupply = 0;
    mapping (address => uint256) public balanceOf;
    mapping (address => mapping (address => uint256)) public allowance;

    event Transfer(address indexed _from, address indexed _to, uint256 _value);
    event Approval(address indexed _owner, address indexed _spender, uint256 _value);

    /**
        @dev constructor

        @param _name        token name
        @param _symbol      token symbol
        @param _decimals    decimal points, for display purposes
    */
    function ERC20Token(string _name, string _symbol, uint8 _decimals) {
        require(bytes(_name).length > 0 && bytes(_symbol).length > 0); // validate input

        name = _name;
        symbol = _symbol;
        decimals = _decimals;
    }

    // validates an address - currently only checks that it isn't null
    modifier validAddress(address _address) {
        require(_address != 0x0);
        _;
    }

    /**
        @dev send coins
        throws on any error rather then return a false flag to minimize user errors

        @param _to      target address
        @param _value   transfer amount

        @return true if the transfer was successful, false if it wasn't
    */
    function transfer(address _to, uint256 _value)
        public
        validAddress(_to)
        returns (bool success)
    {
        balanceOf[msg.sender] = safeSub(balanceOf[msg.sender], _value);
        balanceOf[_to] = safeAdd(balanceOf[_to], _value);
        Transfer(msg.sender, _to, _value);
        return true;
    }

    /**
        @dev an account/contract attempts to get the coins
        throws on any error rather then return a false flag to minimize user errors

        @param _from    source address
        @param _to      target address
        @param _value   transfer amount

        @return true if the transfer was successful, false if it wasn't
    */
    function transferFrom(address _from, address _to, uint256 _value)
        public
        validAddress(_from)
        validAddress(_to)
        returns (bool success)
    {
        allowance[_from][msg.sender] = safeSub(allowance[_from][msg.sender], _value);
        balanceOf[_from] = safeSub(balanceOf[_from], _value);
        balanceOf[_to] = safeAdd(balanceOf[_to], _value);
        Transfer(_from, _to, _value);
        return true;
    }

    /**
        @dev allow another account/contract to spend some tokens on your behalf
        throws on any error rather then return a false flag to minimize user errors

        also, to minimize the risk of the approve/transferFrom attack vector
        (see https://docs.google.com/document/d/1YLPtQxZu1UAvO9cZ1O2RPXBbT0mooh4DYKjA_jp-RLM/), approve has to be called twice
        in 2 separate transactions - once to change the allowance to 0 and secondly to change it to the new allowance value

        @param _spender approved address
        @param _value   allowance amount

        @return true if the approval was successful, false if it wasn't
    */
    function approve(address _spender, uint256 _value)
        public
        validAddress(_spender)
        returns (bool success)
    {
        // if the allowance isn't 0, it can only be updated to 0 to prevent an allowance change immediately after withdrawal
        require(_value == 0 || allowance[msg.sender][_spender] == 0);

        allowance[msg.sender][_spender] = _value;
        Approval(msg.sender, _spender, _value);
        return true;
    }
}

/*
    Smart Token interface
*/
contract ISmartToken is ITokenHolder, IERC20Token {
    function disableTransfers(bool _disable) public;
    function issue(address _to, uint256 _amount) public;
    function destroy(address _from, uint256 _amount) public;
}

/*
    Smart Token v0.2

    'Owned' is specified here for readability reasons
*/
contract SmartToken is ISmartToken, ERC20Token, Owned, TokenHolder {
    string public version = '0.2';

    bool public transfersEnabled = true;    // true if transfer/transferFrom are enabled, false if not

    // triggered when a smart token is deployed - the _token address is defined for forward compatibility, in case we want to trigger the event from a factory
    event NewSmartToken(address _token);
    // triggered when the total supply is increased
    event Issuance(uint256 _amount);
    // triggered when the total supply is decreased
    event Destruction(uint256 _amount);

    /**
        @dev constructor

        @param _name       token name
        @param _symbol     token short symbol, 1-6 characters
        @param _decimals   for display purposes only
    */
    function SmartToken(string _name, string _symbol, uint8 _decimals)
        ERC20Token(_name, _symbol, _decimals)
    {
        require(bytes(_symbol).length <= 6); // validate input
        NewSmartToken(address(this));
    }

    // allows execution only when transfers aren't disabled
    modifier transfersAllowed {
        assert(transfersEnabled);
        _;
    }

    /**
        @dev disables/enables transfers
        can only be called by the contract owner

        @param _disable    true to disable transfers, false to enable them
    */
    function disableTransfers(bool _disable) public ownerOnly {
        transfersEnabled = !_disable;
    }

    /**
        @dev increases the token supply and sends the new tokens to an account
        can only be called by the contract owner

        @param _to         account to receive the new amount
        @param _amount     amount to increase the supply by
    */
    function issue(address _to, uint256 _amount)
        public
        ownerOnly
        validAddress(_to)
        notThis(_to)
    {
        totalSupply = safeAdd(totalSupply, _amount);
        balanceOf[_to] = safeAdd(balanceOf[_to], _amount);

        Issuance(_amount);
        Transfer(this, _to, _amount);
    }

    /**
        @dev removes tokens from an account and decreases the token supply
        can only be called by the contract owner

        @param _from       account to remove the amount from
        @param _amount     amount to decrease the supply by
    */
    function destroy(address _from, uint256 _amount)
        public
        ownerOnly
    {
        balanceOf[_from] = safeSub(balanceOf[_from], _amount);
        totalSupply = safeSub(totalSupply, _amount);

        Transfer(_from, this, _amount);
        Destruction(_amount);
    }

    // ERC20 standard method overrides with some extra functionality

    /**
        @dev send coins
        throws on any error rather then return a false flag to minimize user errors
        note that when transferring to the smart token's address, the coins are actually destroyed

        @param _to      target address
        @param _value   transfer amount

        @return true if the transfer was successful, false if it wasn't
    */
    function transfer(address _to, uint256 _value) public transfersAllowed returns (bool success) {
        assert(super.transfer(_to, _value));

        // transferring to the contract address destroys tokens
        if (_to == address(this)) {
            balanceOf[_to] -= _value;
            totalSupply -= _value;
            Destruction(_value);
        }

        return true;
    }

    /**
        @dev an account/contract attempts to get the coins
        throws on any error rather then return a false flag to minimize user errors
        note that when transferring to the smart token's address, the coins are actually destroyed

        @param _from    source address
        @param _to      target address
        @param _value   transfer amount

        @return true if the transfer was successful, false if it wasn't
    */
    function transferFrom(address _from, address _to, uint256 _value) public transfersAllowed returns (bool success) {
        assert(super.transferFrom(_from, _to, _value));

        // transferring to the contract address destroys tokens
        if (_to == address(this)) {
            balanceOf[_to] -= _value;
            totalSupply -= _value;
            Destruction(_value);
        }

        return true;
    }
}

// File: contracts/converter/interfaces/IBancorFormula.sol

pragma solidity 0.4.26;

/*
    Bancor Formula interface
*/
contract IBancorFormula {
    function calculatePurchaseReturn(uint256 _supply, uint256 _reserveBalance, uint32 _reserveRatio, uint256 _depositAmount) public view returns (uint256);
    function calculateSaleReturn(uint256 _supply, uint256 _reserveBalance, uint32 _reserveRatio, uint256 _sellAmount) public view returns (uint256);
    function calculateCrossReserveReturn(uint256 _fromReserveBalance, uint32 _fromReserveRatio, uint256 _toReserveBalance, uint32 _toReserveRatio, uint256 _amount) public view returns (uint256);
    function calculateFundCost(uint256 _supply, uint256 _reserveBalance, uint32 _totalRatio, uint256 _amount) public view returns (uint256);
    function calculateLiquidateReturn(uint256 _supply, uint256 _reserveBalance, uint32 _totalRatio, uint256 _amount) public view returns (uint256);
    // deprecated, backward compatibility
    function calculateCrossConnectorReturn(uint256 _fromConnectorBalance, uint32 _fromConnectorWeight, uint256 _toConnectorBalance, uint32 _toConnectorWeight, uint256 _amount) public view returns (uint256);
}

// File: contracts/utility/SafeMath.sol

pragma solidity 0.4.26;

/**
  * @dev Library for basic math operations with overflow/underflow protection
*/
library SafeMath {
    /**
      * @dev returns the sum of _x and _y, reverts if the calculation overflows
      * 
      * @param _x   value 1
      * @param _y   value 2
      * 
      * @return sum
    */
    function add(uint256 _x, uint256 _y) internal pure returns (uint256) {
        uint256 z = _x + _y;
        require(z >= _x);
        return z;
    }

    /**
      * @dev returns the difference of _x minus _y, reverts if the calculation underflows
      * 
      * @param _x   minuend
      * @param _y   subtrahend
      * 
      * @return difference
    */
    function sub(uint256 _x, uint256 _y) internal pure returns (uint256) {
        require(_x >= _y);
        return _x - _y;
    }

    /**
      * @dev returns the product of multiplying _x by _y, reverts if the calculation overflows
      * 
      * @param _x   factor 1
      * @param _y   factor 2
      * 
      * @return product
    */
    function mul(uint256 _x, uint256 _y) internal pure returns (uint256) {
        // gas optimization
        if (_x == 0)
            return 0;

        uint256 z = _x * _y;
        require(z / _x == _y);
        return z;
    }

      /**
        * ev Integer division of two numbers truncating the quotient, reverts on division by zero.
        * 
        * aram _x   dividend
        * aram _y   divisor
        * 
        * eturn quotient
    */
    function div(uint256 _x, uint256 _y) internal pure returns (uint256) {
        require(_y > 0);
        uint256 c = _x / _y;

        return c;
    }
}

// File: contracts/utility/Utils.sol

pragma solidity 0.4.26;

/**
  * @dev Utilities & Common Modifiers
*/
contract Utils {
    /**
      * constructor
    */
    constructor() public {
    }

    // verifies that an amount is greater than zero
    modifier greaterThanZero(uint256 _amount) {
        require(_amount > 0);
        _;
    }

    // validates an address - currently only checks that it isn't null
    modifier validAddress(address _address) {
        require(_address != address(0));
        _;
    }

    // verifies that the address is different than this contract address
    modifier notThis(address _address) {
        require(_address != address(this));
        _;
    }

}

// File: contracts/converter/BancorFormula.sol

pragma solidity 0.4.26;




contract BancorFormula is IBancorFormula, Utils {
    using SafeMath for uint256;

    uint16 public version = 6;

    uint256 private constant ONE = 1;
    uint32 private constant MAX_RATIO = 1000000;
    uint8 private constant MIN_PRECISION = 32;
    uint8 private constant MAX_PRECISION = 127;

    /**
      * Auto-generated via 'PrintIntScalingFactors.py'
    */
    uint256 private constant FIXED_1 = 0x080000000000000000000000000000000;
    uint256 private constant FIXED_2 = 0x100000000000000000000000000000000;
    uint256 private constant MAX_NUM = 0x200000000000000000000000000000000;

    /**
      * Auto-generated via 'PrintLn2ScalingFactors.py'
    */
    uint256 private constant LN2_NUMERATOR   = 0x3f80fe03f80fe03f80fe03f80fe03f8;
    uint256 private constant LN2_DENOMINATOR = 0x5b9de1d10bf4103d647b0955897ba80;

    /**
      * Auto-generated via 'PrintFunctionOptimalLog.py' and 'PrintFunctionOptimalExp.py'
    */
    uint256 private constant OPT_LOG_MAX_VAL = 0x15bf0a8b1457695355fb8ac404e7a79e3;
    uint256 private constant OPT_EXP_MAX_VAL = 0x800000000000000000000000000000000;

    /**
      * Auto-generated via 'PrintFunctionConstructor.py'
    */
    uint256[128] private maxExpArray;
    constructor() public {
    //  maxExpArray[  0] = 0x6bffffffffffffffffffffffffffffffff;
    //  maxExpArray[  1] = 0x67ffffffffffffffffffffffffffffffff;
    //  maxExpArray[  2] = 0x637fffffffffffffffffffffffffffffff;
    //  maxExpArray[  3] = 0x5f6fffffffffffffffffffffffffffffff;
    //  maxExpArray[  4] = 0x5b77ffffffffffffffffffffffffffffff;
    //  maxExpArray[  5] = 0x57b3ffffffffffffffffffffffffffffff;
    //  maxExpArray[  6] = 0x5419ffffffffffffffffffffffffffffff;
    //  maxExpArray[  7] = 0x50a2ffffffffffffffffffffffffffffff;
    //  maxExpArray[  8] = 0x4d517fffffffffffffffffffffffffffff;
    //  maxExpArray[  9] = 0x4a233fffffffffffffffffffffffffffff;
    //  maxExpArray[ 10] = 0x47165fffffffffffffffffffffffffffff;
    //  maxExpArray[ 11] = 0x4429afffffffffffffffffffffffffffff;
    //  maxExpArray[ 12] = 0x415bc7ffffffffffffffffffffffffffff;
    //  maxExpArray[ 13] = 0x3eab73ffffffffffffffffffffffffffff;
    //  maxExpArray[ 14] = 0x3c1771ffffffffffffffffffffffffffff;
    //  maxExpArray[ 15] = 0x399e96ffffffffffffffffffffffffffff;
    //  maxExpArray[ 16] = 0x373fc47fffffffffffffffffffffffffff;
    //  maxExpArray[ 17] = 0x34f9e8ffffffffffffffffffffffffffff;
    //  maxExpArray[ 18] = 0x32cbfd5fffffffffffffffffffffffffff;
    //  maxExpArray[ 19] = 0x30b5057fffffffffffffffffffffffffff;
    //  maxExpArray[ 20] = 0x2eb40f9fffffffffffffffffffffffffff;
    //  maxExpArray[ 21] = 0x2cc8340fffffffffffffffffffffffffff;
    //  maxExpArray[ 22] = 0x2af09481ffffffffffffffffffffffffff;
    //  maxExpArray[ 23] = 0x292c5bddffffffffffffffffffffffffff;
    //  maxExpArray[ 24] = 0x277abdcdffffffffffffffffffffffffff;
    //  maxExpArray[ 25] = 0x25daf6657fffffffffffffffffffffffff;
    //  maxExpArray[ 26] = 0x244c49c65fffffffffffffffffffffffff;
    //  maxExpArray[ 27] = 0x22ce03cd5fffffffffffffffffffffffff;
    //  maxExpArray[ 28] = 0x215f77c047ffffffffffffffffffffffff;
    //  maxExpArray[ 29] = 0x1fffffffffffffffffffffffffffffffff;
    //  maxExpArray[ 30] = 0x1eaefdbdabffffffffffffffffffffffff;
    //  maxExpArray[ 31] = 0x1d6bd8b2ebffffffffffffffffffffffff;
        maxExpArray[ 32] = 0x1c35fedd14ffffffffffffffffffffffff;
        maxExpArray[ 33] = 0x1b0ce43b323fffffffffffffffffffffff;
        maxExpArray[ 34] = 0x19f0028ec1ffffffffffffffffffffffff;
        maxExpArray[ 35] = 0x18ded91f0e7fffffffffffffffffffffff;
        maxExpArray[ 36] = 0x17d8ec7f0417ffffffffffffffffffffff;
        maxExpArray[ 37] = 0x16ddc6556cdbffffffffffffffffffffff;
        maxExpArray[ 38] = 0x15ecf52776a1ffffffffffffffffffffff;
        maxExpArray[ 39] = 0x15060c256cb2ffffffffffffffffffffff;
        maxExpArray[ 40] = 0x1428a2f98d72ffffffffffffffffffffff;
        maxExpArray[ 41] = 0x13545598e5c23fffffffffffffffffffff;
        maxExpArray[ 42] = 0x1288c4161ce1dfffffffffffffffffffff;
        maxExpArray[ 43] = 0x11c592761c666fffffffffffffffffffff;
        maxExpArray[ 44] = 0x110a688680a757ffffffffffffffffffff;
        maxExpArray[ 45] = 0x1056f1b5bedf77ffffffffffffffffffff;
        maxExpArray[ 46] = 0x0faadceceeff8bffffffffffffffffffff;
        maxExpArray[ 47] = 0x0f05dc6b27edadffffffffffffffffffff;
        maxExpArray[ 48] = 0x0e67a5a25da4107fffffffffffffffffff;
        maxExpArray[ 49] = 0x0dcff115b14eedffffffffffffffffffff;
        maxExpArray[ 50] = 0x0d3e7a392431239fffffffffffffffffff;
        maxExpArray[ 51] = 0x0cb2ff529eb71e4fffffffffffffffffff;
        maxExpArray[ 52] = 0x0c2d415c3db974afffffffffffffffffff;
        maxExpArray[ 53] = 0x0bad03e7d883f69bffffffffffffffffff;
        maxExpArray[ 54] = 0x0b320d03b2c343d5ffffffffffffffffff;
        maxExpArray[ 55] = 0x0abc25204e02828dffffffffffffffffff;
        maxExpArray[ 56] = 0x0a4b16f74ee4bb207fffffffffffffffff;
        maxExpArray[ 57] = 0x09deaf736ac1f569ffffffffffffffffff;
        maxExpArray[ 58] = 0x0976bd9952c7aa957fffffffffffffffff;
        maxExpArray[ 59] = 0x09131271922eaa606fffffffffffffffff;
        maxExpArray[ 60] = 0x08b380f3558668c46fffffffffffffffff;
        maxExpArray[ 61] = 0x0857ddf0117efa215bffffffffffffffff;
        maxExpArray[ 62] = 0x07ffffffffffffffffffffffffffffffff;
        maxExpArray[ 63] = 0x07abbf6f6abb9d087fffffffffffffffff;
        maxExpArray[ 64] = 0x075af62cbac95f7dfa7fffffffffffffff;
        maxExpArray[ 65] = 0x070d7fb7452e187ac13fffffffffffffff;
        maxExpArray[ 66] = 0x06c3390ecc8af379295fffffffffffffff;
        maxExpArray[ 67] = 0x067c00a3b07ffc01fd6fffffffffffffff;
        maxExpArray[ 68] = 0x0637b647c39cbb9d3d27ffffffffffffff;
        maxExpArray[ 69] = 0x05f63b1fc104dbd39587ffffffffffffff;
        maxExpArray[ 70] = 0x05b771955b36e12f7235ffffffffffffff;
        maxExpArray[ 71] = 0x057b3d49dda84556d6f6ffffffffffffff;
        maxExpArray[ 72] = 0x054183095b2c8ececf30ffffffffffffff;
        maxExpArray[ 73] = 0x050a28be635ca2b888f77fffffffffffff;
        maxExpArray[ 74] = 0x04d5156639708c9db33c3fffffffffffff;
        maxExpArray[ 75] = 0x04a23105873875bd52dfdfffffffffffff;
        maxExpArray[ 76] = 0x0471649d87199aa990756fffffffffffff;
        maxExpArray[ 77] = 0x04429a21a029d4c1457cfbffffffffffff;
        maxExpArray[ 78] = 0x0415bc6d6fb7dd71af2cb3ffffffffffff;
        maxExpArray[ 79] = 0x03eab73b3bbfe282243ce1ffffffffffff;
        maxExpArray[ 80] = 0x03c1771ac9fb6b4c18e229ffffffffffff;
        maxExpArray[ 81] = 0x0399e96897690418f785257fffffffffff;
        maxExpArray[ 82] = 0x0373fc456c53bb779bf0ea9fffffffffff;
        maxExpArray[ 83] = 0x034f9e8e490c48e67e6ab8bfffffffffff;
        maxExpArray[ 84] = 0x032cbfd4a7adc790560b3337ffffffffff;
        maxExpArray[ 85] = 0x030b50570f6e5d2acca94613ffffffffff;
        maxExpArray[ 86] = 0x02eb40f9f620fda6b56c2861ffffffffff;
        maxExpArray[ 87] = 0x02cc8340ecb0d0f520a6af58ffffffffff;
        maxExpArray[ 88] = 0x02af09481380a0a35cf1ba02ffffffffff;
        maxExpArray[ 89] = 0x0292c5bdd3b92ec810287b1b3fffffffff;
        maxExpArray[ 90] = 0x0277abdcdab07d5a77ac6d6b9fffffffff;
        maxExpArray[ 91] = 0x025daf6654b1eaa55fd64df5efffffffff;
        maxExpArray[ 92] = 0x0244c49c648baa98192dce88b7ffffffff;
        maxExpArray[ 93] = 0x022ce03cd5619a311b2471268bffffffff;
        maxExpArray[ 94] = 0x0215f77c045fbe885654a44a0fffffffff;
        maxExpArray[ 95] = 0x01ffffffffffffffffffffffffffffffff;
        maxExpArray[ 96] = 0x01eaefdbdaaee7421fc4d3ede5ffffffff;
        maxExpArray[ 97] = 0x01d6bd8b2eb257df7e8ca57b09bfffffff;
        maxExpArray[ 98] = 0x01c35fedd14b861eb0443f7f133fffffff;
        maxExpArray[ 99] = 0x01b0ce43b322bcde4a56e8ada5afffffff;
        maxExpArray[100] = 0x019f0028ec1fff007f5a195a39dfffffff;
        maxExpArray[101] = 0x018ded91f0e72ee74f49b15ba527ffffff;
        maxExpArray[102] = 0x017d8ec7f04136f4e5615fd41a63ffffff;
        maxExpArray[103] = 0x016ddc6556cdb84bdc8d12d22e6fffffff;
        maxExpArray[104] = 0x015ecf52776a1155b5bd8395814f7fffff;
        maxExpArray[105] = 0x015060c256cb23b3b3cc3754cf40ffffff;
        maxExpArray[106] = 0x01428a2f98d728ae223ddab715be3fffff;
        maxExpArray[107] = 0x013545598e5c23276ccf0ede68034fffff;
        maxExpArray[108] = 0x01288c4161ce1d6f54b7f61081194fffff;
        maxExpArray[109] = 0x011c592761c666aa641d5a01a40f17ffff;
        maxExpArray[110] = 0x0110a688680a7530515f3e6e6cfdcdffff;
        maxExpArray[111] = 0x01056f1b5bedf75c6bcb2ce8aed428ffff;
        maxExpArray[112] = 0x00faadceceeff8a0890f3875f008277fff;
        maxExpArray[113] = 0x00f05dc6b27edad306388a600f6ba0bfff;
        maxExpArray[114] = 0x00e67a5a25da41063de1495d5b18cdbfff;
        maxExpArray[115] = 0x00dcff115b14eedde6fc3aa5353f2e4fff;
        maxExpArray[116] = 0x00d3e7a3924312399f9aae2e0f868f8fff;
        maxExpArray[117] = 0x00cb2ff529eb71e41582cccd5a1ee26fff;
        maxExpArray[118] = 0x00c2d415c3db974ab32a51840c0b67edff;
        maxExpArray[119] = 0x00bad03e7d883f69ad5b0a186184e06bff;
        maxExpArray[120] = 0x00b320d03b2c343d4829abd6075f0cc5ff;
        maxExpArray[121] = 0x00abc25204e02828d73c6e80bcdb1a95bf;
        maxExpArray[122] = 0x00a4b16f74ee4bb2040a1ec6c15fbbf2df;
        maxExpArray[123] = 0x009deaf736ac1f569deb1b5ae3f36c130f;
        maxExpArray[124] = 0x00976bd9952c7aa957f5937d790ef65037;
        maxExpArray[125] = 0x009131271922eaa6064b73a22d0bd4f2bf;
        maxExpArray[126] = 0x008b380f3558668c46c91c49a2f8e967b9;
        maxExpArray[127] = 0x00857ddf0117efa215952912839f6473e6;
    }

    /**
      * @dev given a token supply, reserve balance, ratio and a deposit amount (in the reserve token),
      * calculates the return for a given conversion (in the main token)
      * 
      * Formula:
      * Return = _supply * ((1 + _depositAmount / _reserveBalance) ^ (_reserveRatio / 1000000) - 1)
      * 
      * @param _supply              token total supply
      * @param _reserveBalance      total reserve balance
      * @param _reserveRatio        reserve ratio, represented in ppm, 1-1000000
      * @param _depositAmount       deposit amount, in reserve token
      * 
      * @return purchase return amount
    */
    function calculatePurchaseReturn(uint256 _supply, uint256 _reserveBalance, uint32 _reserveRatio, uint256 _depositAmount) public view returns (uint256) {
        // validate input
        require(_supply > 0 && _reserveBalance > 0 && _reserveRatio > 0 && _reserveRatio <= MAX_RATIO);

        // special case for 0 deposit amount
        if (_depositAmount == 0)
            return 0;

        // special case if the ratio = 100%
        if (_reserveRatio == MAX_RATIO)
            return _supply.mul(_depositAmount) / _reserveBalance;

        uint256 result;
        uint8 precision;
        uint256 baseN = _depositAmount.add(_reserveBalance);
        (result, precision) = power(baseN, _reserveBalance, _reserveRatio, MAX_RATIO);
        uint256 temp = _supply.mul(result) >> precision;
        return temp - _supply;
    }

    /**
      * @dev given a token supply, reserve balance, ratio and a sell amount (in the main token),
      * calculates the return for a given conversion (in the reserve token)
      * 
      * Formula:
      * Return = _reserveBalance * (1 - (1 - _sellAmount / _supply) ^ (1000000 / _reserveRatio))
      * 
      * @param _supply              token total supply
      * @param _reserveBalance      total reserve
      * @param _reserveRatio        constant reserve Ratio, represented in ppm, 1-1000000
      * @param _sellAmount          sell amount, in the token itself
      * 
      * @return sale return amount
    */
    function calculateSaleReturn(uint256 _supply, uint256 _reserveBalance, uint32 _reserveRatio, uint256 _sellAmount) public view returns (uint256) {
        // validate input
        require(_supply > 0 && _reserveBalance > 0 && _reserveRatio > 0 && _reserveRatio <= MAX_RATIO && _sellAmount <= _supply);

        // special case for 0 sell amount
        if (_sellAmount == 0)
            return 0;

        // special case for selling the entire supply
        if (_sellAmount == _supply)
            return _reserveBalance;

        // special case if the ratio = 100%
        if (_reserveRatio == MAX_RATIO)
            return _reserveBalance.mul(_sellAmount) / _supply;

        uint256 result;
        uint8 precision;
        uint256 baseD = _supply - _sellAmount;
        (result, precision) = power(_supply, baseD, MAX_RATIO, _reserveRatio);
        uint256 temp1 = _reserveBalance.mul(result);
        uint256 temp2 = _reserveBalance << precision;
        return (temp1 - temp2) / result;
    }

    /**
      * @dev given two reserve balances/ratios and a sell amount (in the first reserve token),
      * calculates the return for a conversion from the first reserve token to the second reserve token (in the second reserve token)
      * note that prior to version 4, you should use 'calculateCrossConnectorReturn' instead
      * 
      * Formula:
      * Return = _toReserveBalance * (1 - (_fromReserveBalance / (_fromReserveBalance + _amount)) ^ (_fromReserveRatio / _toReserveRatio))
      * 
      * @param _fromReserveBalance      input reserve balance
      * @param _fromReserveRatio        input reserve ratio, represented in ppm, 1-1000000
      * @param _toReserveBalance        output reserve balance
      * @param _toReserveRatio          output reserve ratio, represented in ppm, 1-1000000
      * @param _amount                  input reserve amount
      * 
      * @return second reserve amount
    */
    function calculateCrossReserveReturn(uint256 _fromReserveBalance, uint32 _fromReserveRatio, uint256 _toReserveBalance, uint32 _toReserveRatio, uint256 _amount) public view returns (uint256) {
        // validate input
        require(_fromReserveBalance > 0 && _fromReserveRatio > 0 && _fromReserveRatio <= MAX_RATIO && _toReserveBalance > 0 && _toReserveRatio > 0 && _toReserveRatio <= MAX_RATIO);

        // special case for equal ratios
        if (_fromReserveRatio == _toReserveRatio)
            return _toReserveBalance.mul(_amount) / _fromReserveBalance.add(_amount);

        uint256 result;
        uint8 precision;
        uint256 baseN = _fromReserveBalance.add(_amount);
        (result, precision) = power(baseN, _fromReserveBalance, _fromReserveRatio, _toReserveRatio);
        uint256 temp1 = _toReserveBalance.mul(result);
        uint256 temp2 = _toReserveBalance << precision;
        return (temp1 - temp2) / result;
    }

    /**
      * @dev given a smart token supply, reserve balance, total ratio and an amount of requested smart tokens,
      * calculates the amount of reserve tokens required for purchasing the given amount of smart tokens
      * 
      * Formula:
      * Return = _reserveBalance * (((_supply + _amount) / _supply) ^ (MAX_RATIO / _totalRatio) - 1)
      * 
      * @param _supply              smart token supply
      * @param _reserveBalance      reserve token balance
      * @param _totalRatio          total ratio, represented in ppm, 2-2000000
      * @param _amount              requested amount of smart tokens
      * 
      * @return amount of reserve tokens
    */
    function calculateFundCost(uint256 _supply, uint256 _reserveBalance, uint32 _totalRatio, uint256 _amount) public view returns (uint256) {
        // validate input
        require(_supply > 0 && _reserveBalance > 0 && _totalRatio > 1 && _totalRatio <= MAX_RATIO * 2);

        // special case for 0 amount
        if (_amount == 0)
            return 0;

        // special case if the total ratio = 100%
        if (_totalRatio == MAX_RATIO)
            return (_amount.mul(_reserveBalance) - 1) / _supply + 1;

        uint256 result;
        uint8 precision;
        uint256 baseN = _supply.add(_amount);
        (result, precision) = power(baseN, _supply, MAX_RATIO, _totalRatio);
        uint256 temp = ((_reserveBalance.mul(result) - 1) >> precision) + 1;
        return temp - _reserveBalance;
    }

    /**
      * @dev given a smart token supply, reserve balance, total ratio and an amount of smart tokens to liquidate,
      * calculates the amount of reserve tokens received for selling the given amount of smart tokens
      * 
      * Formula:
      * Return = _reserveBalance * (1 - ((_supply - _amount) / _supply) ^ (MAX_RATIO / _totalRatio))
      * 
      * @param _supply              smart token supply
      * @param _reserveBalance      reserve token balance
      * @param _totalRatio          total ratio, represented in ppm, 2-2000000
      * @param _amount              amount of smart tokens to liquidate
      * 
      * @return amount of reserve tokens
    */
    function calculateLiquidateReturn(uint256 _supply, uint256 _reserveBalance, uint32 _totalRatio, uint256 _amount) public view returns (uint256) {
        // validate input
        require(_supply > 0 && _reserveBalance > 0 && _totalRatio > 1 && _totalRatio <= MAX_RATIO * 2 && _amount <= _supply);

        // special case for 0 amount
        if (_amount == 0)
            return 0;

        // special case for liquidating the entire supply
        if (_amount == _supply)
            return _reserveBalance;

        // special case if the total ratio = 100%
        if (_totalRatio == MAX_RATIO)
            return _amount.mul(_reserveBalance) / _supply;

        uint256 result;
        uint8 precision;
        uint256 baseD = _supply - _amount;
        (result, precision) = power(_supply, baseD, MAX_RATIO, _totalRatio);
        uint256 temp1 = _reserveBalance.mul(result);
        uint256 temp2 = _reserveBalance << precision;
        return (temp1 - temp2) / result;
    }

    /**
      * @dev General Description:
      *     Determine a value of precision.
      *     Calculate an integer approximation of (_baseN / _baseD) ^ (_expN / _expD) * 2 ^ precision.
      *     Return the result along with the precision used.
      * 
      * Detailed Description:
      *     Instead of calculating "base ^ exp", we calculate "e ^ (log(base) * exp)".
      *     The value of "log(base)" is represented with an integer slightly smaller than "log(base) * 2 ^ precision".
      *     The larger "precision" is, the more accurately this value represents the real value.
      *     However, the larger "precision" is, the more bits are required in order to store this value.
      *     And the exponentiation function, which takes "x" and calculates "e ^ x", is limited to a maximum exponent (maximum value of "x").
      *     This maximum exponent depends on the "precision" used, and it is given by "maxExpArray[precision] >> (MAX_PRECISION - precision)".
      *     Hence we need to determine the highest precision which can be used for the given input, before calling the exponentiation function.
      *     This allows us to compute "base ^ exp" with maximum accuracy and without exceeding 256 bits in any of the intermediate computations.
      *     This functions assumes that "_expN < 2 ^ 256 / log(MAX_NUM - 1)", otherwise the multiplication should be replaced with a "safeMul".
      *     Since we rely on unsigned-integer arithmetic and "base < 1" ==> "log(base) < 0", this function does not support "_baseN < _baseD".
    */
    function power(uint256 _baseN, uint256 _baseD, uint32 _expN, uint32 _expD) internal view returns (uint256, uint8) {
        require(_baseN < MAX_NUM);

        uint256 baseLog;
        uint256 base = _baseN * FIXED_1 / _baseD;
        if (base < OPT_LOG_MAX_VAL) {
            baseLog = optimalLog(base);
        }
        else {
            baseLog = generalLog(base);
        }

        uint256 baseLogTimesExp = baseLog * _expN / _expD;
        if (baseLogTimesExp < OPT_EXP_MAX_VAL) {
            return (optimalExp(baseLogTimesExp), MAX_PRECISION);
        }
        else {
            uint8 precision = findPositionInMaxExpArray(baseLogTimesExp);
            return (generalExp(baseLogTimesExp >> (MAX_PRECISION - precision), precision), precision);
        }
    }

    /**
      * @dev computes log(x / FIXED_1) * FIXED_1.
      * This functions assumes that "x >= FIXED_1", because the output would be negative otherwise.
    */
    function generalLog(uint256 x) internal pure returns (uint256) {
        uint256 res = 0;

        // If x >= 2, then we compute the integer part of log2(x), which is larger than 0.
        if (x >= FIXED_2) {
            uint8 count = floorLog2(x / FIXED_1);
            x >>= count; // now x < 2
            res = count * FIXED_1;
        }

        // If x > 1, then we compute the fraction part of log2(x), which is larger than 0.
        if (x > FIXED_1) {
            for (uint8 i = MAX_PRECISION; i > 0; --i) {
                x = (x * x) / FIXED_1; // now 1 < x < 4
                if (x >= FIXED_2) {
                    x >>= 1; // now 1 < x < 2
                    res += ONE << (i - 1);
                }
            }
        }

        return res * LN2_NUMERATOR / LN2_DENOMINATOR;
    }

    /**
      * @dev computes the largest integer smaller than or equal to the binary logarithm of the input.
    */
    function floorLog2(uint256 _n) internal pure returns (uint8) {
        uint8 res = 0;

        if (_n < 256) {
            // At most 8 iterations
            while (_n > 1) {
                _n >>= 1;
                res += 1;
            }
        }
        else {
            // Exactly 8 iterations
            for (uint8 s = 128; s > 0; s >>= 1) {
                if (_n >= (ONE << s)) {
                    _n >>= s;
                    res |= s;
                }
            }
        }

        return res;
    }

    /**
      * @dev the global "maxExpArray" is sorted in descending order, and therefore the following statements are equivalent:
      * - This function finds the position of [the smallest value in "maxExpArray" larger than or equal to "x"]
      * - This function finds the highest position of [a value in "maxExpArray" larger than or equal to "x"]
    */
    function findPositionInMaxExpArray(uint256 _x) internal view returns (uint8) {
        uint8 lo = MIN_PRECISION;
        uint8 hi = MAX_PRECISION;

        while (lo + 1 < hi) {
            uint8 mid = (lo + hi) / 2;
            if (maxExpArray[mid] >= _x)
                lo = mid;
            else
                hi = mid;
        }

        if (maxExpArray[hi] >= _x)
            return hi;
        if (maxExpArray[lo] >= _x)
            return lo;

        require(false);
        return 0;
    }

    /**
      * @dev this function can be auto-generated by the script 'PrintFunctionGeneralExp.py'.
      * it approximates "e ^ x" via maclaurin summation: "(x^0)/0! + (x^1)/1! + ... + (x^n)/n!".
      * it returns "e ^ (x / 2 ^ precision) * 2 ^ precision", that is, the result is upshifted for accuracy.
      * the global "maxExpArray" maps each "precision" to "((maximumExponent + 1) << (MAX_PRECISION - precision)) - 1".
      * the maximum permitted value for "x" is therefore given by "maxExpArray[precision] >> (MAX_PRECISION - precision)".
    */
    function generalExp(uint256 _x, uint8 _precision) internal pure returns (uint256) {
        uint256 xi = _x;
        uint256 res = 0;

        xi = (xi * _x) >> _precision; res += xi * 0x3442c4e6074a82f1797f72ac0000000; // add x^02 * (33! / 02!)
        xi = (xi * _x) >> _precision; res += xi * 0x116b96f757c380fb287fd0e40000000; // add x^03 * (33! / 03!)
        xi = (xi * _x) >> _precision; res += xi * 0x045ae5bdd5f0e03eca1ff4390000000; // add x^04 * (33! / 04!)
        xi = (xi * _x) >> _precision; res += xi * 0x00defabf91302cd95b9ffda50000000; // add x^05 * (33! / 05!)
        xi = (xi * _x) >> _precision; res += xi * 0x002529ca9832b22439efff9b8000000; // add x^06 * (33! / 06!)
        xi = (xi * _x) >> _precision; res += xi * 0x00054f1cf12bd04e516b6da88000000; // add x^07 * (33! / 07!)
        xi = (xi * _x) >> _precision; res += xi * 0x0000a9e39e257a09ca2d6db51000000; // add x^08 * (33! / 08!)
        xi = (xi * _x) >> _precision; res += xi * 0x000012e066e7b839fa050c309000000; // add x^09 * (33! / 09!)
        xi = (xi * _x) >> _precision; res += xi * 0x000001e33d7d926c329a1ad1a800000; // add x^10 * (33! / 10!)
        xi = (xi * _x) >> _precision; res += xi * 0x0000002bee513bdb4a6b19b5f800000; // add x^11 * (33! / 11!)
        xi = (xi * _x) >> _precision; res += xi * 0x00000003a9316fa79b88eccf2a00000; // add x^12 * (33! / 12!)
        xi = (xi * _x) >> _precision; res += xi * 0x0000000048177ebe1fa812375200000; // add x^13 * (33! / 13!)
        xi = (xi * _x) >> _precision; res += xi * 0x0000000005263fe90242dcbacf00000; // add x^14 * (33! / 14!)
        xi = (xi * _x) >> _precision; res += xi * 0x000000000057e22099c030d94100000; // add x^15 * (33! / 15!)
        xi = (xi * _x) >> _precision; res += xi * 0x0000000000057e22099c030d9410000; // add x^16 * (33! / 16!)
        xi = (xi * _x) >> _precision; res += xi * 0x00000000000052b6b54569976310000; // add x^17 * (33! / 17!)
        xi = (xi * _x) >> _precision; res += xi * 0x00000000000004985f67696bf748000; // add x^18 * (33! / 18!)
        xi = (xi * _x) >> _precision; res += xi * 0x000000000000003dea12ea99e498000; // add x^19 * (33! / 19!)
        xi = (xi * _x) >> _precision; res += xi * 0x00000000000000031880f2214b6e000; // add x^20 * (33! / 20!)
        xi = (xi * _x) >> _precision; res += xi * 0x000000000000000025bcff56eb36000; // add x^21 * (33! / 21!)
        xi = (xi * _x) >> _precision; res += xi * 0x000000000000000001b722e10ab1000; // add x^22 * (33! / 22!)
        xi = (xi * _x) >> _precision; res += xi * 0x0000000000000000001317c70077000; // add x^23 * (33! / 23!)
        xi = (xi * _x) >> _precision; res += xi * 0x00000000000000000000cba84aafa00; // add x^24 * (33! / 24!)
        xi = (xi * _x) >> _precision; res += xi * 0x00000000000000000000082573a0a00; // add x^25 * (33! / 25!)
        xi = (xi * _x) >> _precision; res += xi * 0x00000000000000000000005035ad900; // add x^26 * (33! / 26!)
        xi = (xi * _x) >> _precision; res += xi * 0x000000000000000000000002f881b00; // add x^27 * (33! / 27!)
        xi = (xi * _x) >> _precision; res += xi * 0x0000000000000000000000001b29340; // add x^28 * (33! / 28!)
        xi = (xi * _x) >> _precision; res += xi * 0x00000000000000000000000000efc40; // add x^29 * (33! / 29!)
        xi = (xi * _x) >> _precision; res += xi * 0x0000000000000000000000000007fe0; // add x^30 * (33! / 30!)
        xi = (xi * _x) >> _precision; res += xi * 0x0000000000000000000000000000420; // add x^31 * (33! / 31!)
        xi = (xi * _x) >> _precision; res += xi * 0x0000000000000000000000000000021; // add x^32 * (33! / 32!)
        xi = (xi * _x) >> _precision; res += xi * 0x0000000000000000000000000000001; // add x^33 * (33! / 33!)

        return res / 0x688589cc0e9505e2f2fee5580000000 + _x + (ONE << _precision); // divide by 33! and then add x^1 / 1! + x^0 / 0!
    }

    /**
      * @dev computes log(x / FIXED_1) * FIXED_1
      * Input range: FIXED_1 <= x <= LOG_EXP_MAX_VAL - 1
      * Auto-generated via 'PrintFunctionOptimalLog.py'
      * Detailed description:
      * - Rewrite the input as a product of natural exponents and a single residual r, such that 1 < r < 2
      * - The natural logarithm of each (pre-calculated) exponent is the degree of the exponent
      * - The natural logarithm of r is calculated via Taylor series for log(1 + x), where x = r - 1
      * - The natural logarithm of the input is calculated by summing up the intermediate results above
      * - For example: log(250) = log(e^4 * e^1 * e^0.5 * 1.021692859) = 4 + 1 + 0.5 + log(1 + 0.021692859)
    */
    function optimalLog(uint256 x) internal pure returns (uint256) {
        uint256 res = 0;

        uint256 y;
        uint256 z;
        uint256 w;

        if (x >= 0xd3094c70f034de4b96ff7d5b6f99fcd8) {res += 0x40000000000000000000000000000000; x = x * FIXED_1 / 0xd3094c70f034de4b96ff7d5b6f99fcd8;} // add 1 / 2^1
        if (x >= 0xa45af1e1f40c333b3de1db4dd55f29a7) {res += 0x20000000000000000000000000000000; x = x * FIXED_1 / 0xa45af1e1f40c333b3de1db4dd55f29a7;} // add 1 / 2^2
        if (x >= 0x910b022db7ae67ce76b441c27035c6a1) {res += 0x10000000000000000000000000000000; x = x * FIXED_1 / 0x910b022db7ae67ce76b441c27035c6a1;} // add 1 / 2^3
        if (x >= 0x88415abbe9a76bead8d00cf112e4d4a8) {res += 0x08000000000000000000000000000000; x = x * FIXED_1 / 0x88415abbe9a76bead8d00cf112e4d4a8;} // add 1 / 2^4
        if (x >= 0x84102b00893f64c705e841d5d4064bd3) {res += 0x04000000000000000000000000000000; x = x * FIXED_1 / 0x84102b00893f64c705e841d5d4064bd3;} // add 1 / 2^5
        if (x >= 0x8204055aaef1c8bd5c3259f4822735a2) {res += 0x02000000000000000000000000000000; x = x * FIXED_1 / 0x8204055aaef1c8bd5c3259f4822735a2;} // add 1 / 2^6
        if (x >= 0x810100ab00222d861931c15e39b44e99) {res += 0x01000000000000000000000000000000; x = x * FIXED_1 / 0x810100ab00222d861931c15e39b44e99;} // add 1 / 2^7
        if (x >= 0x808040155aabbbe9451521693554f733) {res += 0x00800000000000000000000000000000; x = x * FIXED_1 / 0x808040155aabbbe9451521693554f733;} // add 1 / 2^8

        z = y = x - FIXED_1;
        w = y * y / FIXED_1;
        res += z * (0x100000000000000000000000000000000 - y) / 0x100000000000000000000000000000000; z = z * w / FIXED_1; // add y^01 / 01 - y^02 / 02
        res += z * (0x0aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa - y) / 0x200000000000000000000000000000000; z = z * w / FIXED_1; // add y^03 / 03 - y^04 / 04
        res += z * (0x099999999999999999999999999999999 - y) / 0x300000000000000000000000000000000; z = z * w / FIXED_1; // add y^05 / 05 - y^06 / 06
        res += z * (0x092492492492492492492492492492492 - y) / 0x400000000000000000000000000000000; z = z * w / FIXED_1; // add y^07 / 07 - y^08 / 08
        res += z * (0x08e38e38e38e38e38e38e38e38e38e38e - y) / 0x500000000000000000000000000000000; z = z * w / FIXED_1; // add y^09 / 09 - y^10 / 10
        res += z * (0x08ba2e8ba2e8ba2e8ba2e8ba2e8ba2e8b - y) / 0x600000000000000000000000000000000; z = z * w / FIXED_1; // add y^11 / 11 - y^12 / 12
        res += z * (0x089d89d89d89d89d89d89d89d89d89d89 - y) / 0x700000000000000000000000000000000; z = z * w / FIXED_1; // add y^13 / 13 - y^14 / 14
        res += z * (0x088888888888888888888888888888888 - y) / 0x800000000000000000000000000000000;                      // add y^15 / 15 - y^16 / 16

        return res;
    }

    /**
      * @dev computes e ^ (x / FIXED_1) * FIXED_1
      * input range: 0 <= x <= OPT_EXP_MAX_VAL - 1
      * auto-generated via 'PrintFunctionOptimalExp.py'
      * Detailed description:
      * - Rewrite the input as a sum of binary exponents and a single residual r, as small as possible
      * - The exponentiation of each binary exponent is given (pre-calculated)
      * - The exponentiation of r is calculated via Taylor series for e^x, where x = r
      * - The exponentiation of the input is calculated by multiplying the intermediate results above
      * - For example: e^5.521692859 = e^(4 + 1 + 0.5 + 0.021692859) = e^4 * e^1 * e^0.5 * e^0.021692859
    */
    function optimalExp(uint256 x) internal pure returns (uint256) {
        uint256 res = 0;

        uint256 y;
        uint256 z;

        z = y = x % 0x10000000000000000000000000000000; // get the input modulo 2^(-3)
        z = z * y / FIXED_1; res += z * 0x10e1b3be415a0000; // add y^02 * (20! / 02!)
        z = z * y / FIXED_1; res += z * 0x05a0913f6b1e0000; // add y^03 * (20! / 03!)
        z = z * y / FIXED_1; res += z * 0x0168244fdac78000; // add y^04 * (20! / 04!)
        z = z * y / FIXED_1; res += z * 0x004807432bc18000; // add y^05 * (20! / 05!)
        z = z * y / FIXED_1; res += z * 0x000c0135dca04000; // add y^06 * (20! / 06!)
        z = z * y / FIXED_1; res += z * 0x0001b707b1cdc000; // add y^07 * (20! / 07!)
        z = z * y / FIXED_1; res += z * 0x000036e0f639b800; // add y^08 * (20! / 08!)
        z = z * y / FIXED_1; res += z * 0x00000618fee9f800; // add y^09 * (20! / 09!)
        z = z * y / FIXED_1; res += z * 0x0000009c197dcc00; // add y^10 * (20! / 10!)
        z = z * y / FIXED_1; res += z * 0x0000000e30dce400; // add y^11 * (20! / 11!)
        z = z * y / FIXED_1; res += z * 0x000000012ebd1300; // add y^12 * (20! / 12!)
        z = z * y / FIXED_1; res += z * 0x0000000017499f00; // add y^13 * (20! / 13!)
        z = z * y / FIXED_1; res += z * 0x0000000001a9d480; // add y^14 * (20! / 14!)
        z = z * y / FIXED_1; res += z * 0x00000000001c6380; // add y^15 * (20! / 15!)
        z = z * y / FIXED_1; res += z * 0x000000000001c638; // add y^16 * (20! / 16!)
        z = z * y / FIXED_1; res += z * 0x0000000000001ab8; // add y^17 * (20! / 17!)
        z = z * y / FIXED_1; res += z * 0x000000000000017c; // add y^18 * (20! / 18!)
        z = z * y / FIXED_1; res += z * 0x0000000000000014; // add y^19 * (20! / 19!)
        z = z * y / FIXED_1; res += z * 0x0000000000000001; // add y^20 * (20! / 20!)
        res = res / 0x21c3677c82b40000 + y + FIXED_1; // divide by 20! and then add y^1 / 1! + y^0 / 0!

        if ((x & 0x010000000000000000000000000000000) != 0) res = res * 0x1c3d6a24ed82218787d624d3e5eba95f9 / 0x18ebef9eac820ae8682b9793ac6d1e776; // multiply by e^2^(-3)
        if ((x & 0x020000000000000000000000000000000) != 0) res = res * 0x18ebef9eac820ae8682b9793ac6d1e778 / 0x1368b2fc6f9609fe7aceb46aa619baed4; // multiply by e^2^(-2)
        if ((x & 0x040000000000000000000000000000000) != 0) res = res * 0x1368b2fc6f9609fe7aceb46aa619baed5 / 0x0bc5ab1b16779be3575bd8f0520a9f21f; // multiply by e^2^(-1)
        if ((x & 0x080000000000000000000000000000000) != 0) res = res * 0x0bc5ab1b16779be3575bd8f0520a9f21e / 0x0454aaa8efe072e7f6ddbab84b40a55c9; // multiply by e^2^(+0)
        if ((x & 0x100000000000000000000000000000000) != 0) res = res * 0x0454aaa8efe072e7f6ddbab84b40a55c5 / 0x00960aadc109e7a3bf4578099615711ea; // multiply by e^2^(+1)
        if ((x & 0x200000000000000000000000000000000) != 0) res = res * 0x00960aadc109e7a3bf4578099615711d7 / 0x0002bf84208204f5977f9a8cf01fdce3d; // multiply by e^2^(+2)
        if ((x & 0x400000000000000000000000000000000) != 0) res = res * 0x0002bf84208204f5977f9a8cf01fdc307 / 0x0000003c6ab775dd0b95b4cbee7e65d11; // multiply by e^2^(+3)

        return res;
    }

    /**
      * @dev deprecated, backward compatibility
    */
    function calculateCrossConnectorReturn(uint256 _fromConnectorBalance, uint32 _fromConnectorWeight, uint256 _toConnectorBalance, uint32 _toConnectorWeight, uint256 _amount) public view returns (uint256) {
        return calculateCrossReserveReturn(_fromConnectorBalance, _fromConnectorWeight, _toConnectorBalance, _toConnectorWeight, _amount);
    }
}

pragma solidity ^0.4.21;

/*
    Owned contract interface
*/
contract IOwned {
    // this function isn't abstract since the compiler emits automatically generated getter functions as external
    function owner() public view returns (address) {}

    function transferOwnership(address _newOwner) public;
    function acceptOwnership() public;
}

/*
    Provides support and utilities for contract ownership
*/
contract Owned is IOwned {
    address public owner;
    address public newOwner;

    event OwnerUpdate(address indexed _prevOwner, address indexed _newOwner);

    /**
        @dev constructor
    */
    function Owned() public {
        owner = msg.sender;
    }

    // allows execution by the owner only
    modifier ownerOnly {
        assert(msg.sender == owner);
        _;
    }

    /**
        @dev allows transferring the contract ownership
        the new owner still needs to accept the transfer
        can only be called by the contract owner

        @param _newOwner    new contract owner
    */
    function transferOwnership(address _newOwner) public ownerOnly {
        require(_newOwner != owner);
        newOwner = _newOwner;
    }

    /**
        @dev used by a new owner to accept an ownership transfer
    */
    function acceptOwnership() public {
        require(msg.sender == newOwner);
        emit OwnerUpdate(owner, newOwner);
        owner = newOwner;
        newOwner = address(0);
    }
}

/*
    Contract Registry interface
*/
contract IContractRegistry {
    function getAddress(bytes32 _contractName) public view returns (address);
}

/**
    Contract Registry

    The contract registry keeps contract addresses by name.
    The owner can update contract addresses so that a contract name always points to the latest version
    of the given contract.
    Other contracts can query the registry to get updated addresses instead of depending on specific
    addresses.

    Note that contract names are limited to 32 bytes, UTF8 strings to optimize gas costs
*/
contract ContractRegistry is IContractRegistry, Owned {
    mapping (bytes32 => address) addresses;

    event AddressUpdate(bytes32 indexed _contractName, address _contractAddress);

    /**
        @dev constructor
    */
    function ContractRegistry() public {
    }

    /**
        @dev returns the address associated with the given contract name

        @param _contractName    contract name

        @return contract address
    */
    function getAddress(bytes32 _contractName) public view returns (address) {
        return addresses[_contractName];
    }

    /**
        @dev registers a new address for the contract name

       @param _contractName     contract name
       @param _contractAddress  contract address
    */
    function registerAddress(bytes32 _contractName, address _contractAddress) public ownerOnly {
        require(_contractName.length > 0); // validating input

        addresses[_contractName] = _contractAddress;
        emit AddressUpdate(_contractName, _contractAddress);
    }
}

pragma solidity ^0.4.4;

/**
 * @title ERC20 interface
 * see https://github.com/ethereum/EIPs/issues/20
 */
contract ERC20 {

  uint public totalSupply;
  uint public decimals;

  function balanceOf(address who) constant returns (uint);
  function allowance(address owner, address spender) constant returns (uint);

  function transfer(address to, uint value) returns (bool ok);
  function transferFrom(address from, address to, uint value) returns (bool ok);
  function approve(address spender, uint value) returns (bool ok);

  event Transfer(address indexed from, address indexed to, uint value);
  event Approval(address indexed owner, address indexed spender, uint value);

}


/**
 * @title Ownable
 * The Ownable contract has an owner address, and provides basic authorization control
 * functions, this simplifies the implementation of "user permissions".
 */
contract Ownable {
  /* Current Owner */
  address public owner;

  /* New owner which can be set in future */
  address public newOwner;

  /* event to indicate finally ownership has been succesfully transferred and accepted */
  event OwnershipTransferred(address indexed _from, address indexed _to);

  /**
   * The Ownable constructor sets the original `owner` of the contract to the sender account.
   */
  function Ownable() {
    owner = msg.sender;
  }

  /**
   * Throws if called by any account other than the owner.
   */
  modifier onlyOwner {
    require(msg.sender == owner);
    _;
  }

  /**
   * Allows the current owner to transfer control of the contract to a newOwner.
   * @param _newOwner The address to transfer ownership to.
   */
  function transferOwnership(address _newOwner) onlyOwner {
    require(_newOwner != address(0));
    newOwner = _newOwner;
  }

  /**
   * Allows the new owner toaccept ownership
   */
  function acceptOwnership() {
    require(msg.sender == newOwner);
    OwnershipTransferred(owner, newOwner);
    owner = newOwner;
  }

}

/*
*This library is used to do mathematics safely
*/
contract SafeMathLib {
  function safeMul(uint a, uint b) returns (uint) {
    uint c = a * b;
    assert(a == 0 || c / a == b);
    return c;
  }

  function safeSub(uint a, uint b) returns (uint) {
    assert(b <= a);
    return a - b;
  }

  function safeAdd(uint a, uint b) returns (uint) {
    uint c = a + b;
    assert(c>=a);
    return c;
  }
}


/**
 * Upgrade agent interface inspired by Lunyr.
 * Taken and inspired from https://tokenmarket.net
 *
 * Upgrade agent transfers tokens to a new version of a token contract.
 * Upgrade agent can be set on a token by the upgrade master.
 *
 * Steps are
 * - Upgradeabletoken.upgradeMaster calls UpgradeableToken.setUpgradeAgent()
 * - Individual token holders can now call UpgradeableToken.upgrade()
 *   -> This results to call UpgradeAgent.upgradeFrom() that issues new tokens
 *   -> UpgradeableToken.upgrade() reduces the original total supply based on amount of upgraded tokens
 *
 * Upgrade agent itself can be the token contract, or just a middle man contract doing the heavy lifting.
 */
contract UpgradeAgent {

  uint public originalSupply;

  /** Interface marker */
  function isUpgradeAgent() public constant returns (bool) {
    return true;
  }

  /**
   * Upgrade amount of tokens to a new version.
   *
   * Only callable by UpgradeableToken.
   *
   * @param _tokenHolder Address that wants to upgrade its tokens
   * @param _amount Number of tokens to upgrade. The address may consider to hold back some amount of tokens in the old version.
   */
  function upgradeFrom(address _tokenHolder, uint256 _amount) external;
}


/**
 * Standard ERC20 token with Short Hand Attack and approve() race condition mitigation.
 *
 * Based on code by FirstBlood:
 * https://github.com/Firstbloodio/token/blob/master/smart_contract/FirstBloodToken.sol
 */
contract StandardToken is ERC20, SafeMathLib {

  /* Actual balances of token holders */
  mapping(address => uint) balances;

  /* approve() allowances */
  mapping (address => mapping (address => uint)) allowed;

  function transfer(address _to, uint _value) returns (bool success) {

      // SafMaths will automatically handle the overflow checks
      balances[msg.sender] = safeSub(balances[msg.sender],_value);
      balances[_to] = safeAdd(balances[_to],_value);
      Transfer(msg.sender, _to, _value);
      return true;

  }

  function transferFrom(address _from, address _to, uint _value) returns (bool success) {

    uint _allowance = allowed[_from][msg.sender];

    // Check is not needed because safeSub(_allowance, _value) will already throw if this condition is not met
    balances[_to] = safeAdd(balances[_to],_value);
    balances[_from] = safeSub(balances[_from],_value);
    allowed[_from][msg.sender] = safeSub(_allowance,_value);
    Transfer(_from, _to, _value);
    return true;

  }

  function balanceOf(address _owner) constant returns (uint balance) {
    return balances[_owner];
  }

  function approve(address _spender, uint _value) returns (bool success) {

    // To change the approve amount you first have to reduce the addresses`
    //  allowance to zero by calling `approve(_spender, 0)` if it is not
    //  already 0 to mitigate the race condition described here:
    //  https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
    require(!((_value != 0) && (allowed[msg.sender][_spender] != 0)));

    allowed[msg.sender][_spender] = _value;
    Approval(msg.sender, _spender, _value);
    return true;
  }

  function allowance(address _owner, address _spender) constant returns (uint remaining) {
    return allowed[_owner][_spender];
  }

}


/**
 * A token upgrade mechanism where users can opt-in amount of tokens to the next smart contract revision.
 * First envisioned by Golem and Lunyr projects.
 * Taken and inspired from https://tokenmarket.net
 */
contract XinfinUpgradeableToken is StandardToken {

  /** Contract / person who can set the upgrade path. This can be the same as team multisig wallet, as what it is with its default value. */
  address public upgradeMaster;

  /** The next contract where the tokens will be migrated. */
  UpgradeAgent public upgradeAgent;

  /** How many tokens we have upgraded by now. */
  uint256 public totalUpgraded;

  /**
   * Upgrade states.
   *
   * - NotAllowed: The child contract has not reached a condition where the upgrade can bgun
   * - WaitingForAgent: Token allows upgrade, but we don't have a new agent yet
   * - ReadyToUpgrade: The agent is set, but not a single token has been upgraded yet
   * - Upgrading: Upgrade agent is set and the balance holders can upgrade their tokens
   *
   */
  enum UpgradeState {Unknown, NotAllowed, WaitingForAgent, ReadyToUpgrade, Upgrading}

  /**
   * Somebody has upgraded some of his tokens.
   */
  event Upgrade(address indexed _from, address indexed _to, uint256 _value);

  /**
   * New upgrade agent available.
   */
  event UpgradeAgentSet(address agent);

  /**
   * Do not allow construction without upgrade master set.
   */
  function XinfinUpgradeableToken(address _upgradeMaster) {
    upgradeMaster = _upgradeMaster;
  }

  /**
   * Allow the token holder to upgrade some of their tokens to a new contract.
   */
  function upgrade(uint256 value) public {

      UpgradeState state = getUpgradeState();
      require(state == UpgradeState.ReadyToUpgrade || state == UpgradeState.Upgrading);

      // Validate input value.
      require(value != 0);

      balances[msg.sender] = safeSub(balances[msg.sender], value);

      // Take tokens out from circulation
      totalSupply = safeSub(totalSupply, value);
      totalUpgraded = safeAdd(totalUpgraded, value);

      // Upgrade agent reissues the tokens
      upgradeAgent.upgradeFrom(msg.sender, value);
      Upgrade(msg.sender, upgradeAgent, value);
  }

  /**
   * Set an upgrade agent that handles
   */
  function setUpgradeAgent(address agent) external {


      // The token is not yet in a state that we could think upgrading
      require(canUpgrade());

      require(agent != 0x0);
      // Only a master can designate the next agent
      require(msg.sender == upgradeMaster);
      // Upgrade has already begun for an agent
      require(getUpgradeState() != UpgradeState.Upgrading);

      upgradeAgent = UpgradeAgent(agent);

      // Bad interface
      require(upgradeAgent.isUpgradeAgent());
      // Make sure that token supplies match in source and target
      require(upgradeAgent.originalSupply() == totalSupply);

      UpgradeAgentSet(upgradeAgent);
  }

  /**
   * Get the state of the token upgrade.
   */
  function getUpgradeState() public constant returns(UpgradeState) {
    if(!canUpgrade()) return UpgradeState.NotAllowed;
    else if(address(upgradeAgent) == 0x00) return UpgradeState.WaitingForAgent;
    else if(totalUpgraded == 0) return UpgradeState.ReadyToUpgrade;
    else return UpgradeState.Upgrading;
  }

  /**
   * Change the upgrade master.
   *
   * This allows us to set a new owner for the upgrade mechanism.
   */
  function setUpgradeMaster(address master) public {
      require(master != 0x0);
      require(msg.sender == upgradeMaster);
      upgradeMaster = master;
  }

  /**
   * Child contract can enable to provide the condition when the upgrade can begun.
   */
  function canUpgrade() public constant returns(bool) {
     return true;
  }

}


/**
 * Define interface for releasing the token transfer after a successful crowdsale.
 * Taken and inspired from https://tokenmarket.net
 */
contract ReleasableToken is ERC20, Ownable {

  /* The finalizer contract that allows unlift the transfer limits on this token */
  address public releaseAgent;

  /** A crowdsale contract can release us to the wild if ICO success. If false we are are in transfer lock up period.*/
  bool public released = false;

  /** Map of agents that are allowed to transfer tokens regardless of the lock down period. These are crowdsale contracts and possible the team multisig itself. */
  mapping (address => bool) public transferAgents;

  /**
   * Limit token transfer until the crowdsale is over.
   *
   */
  modifier canTransfer(address _sender) {

    if(!released) {
        require(transferAgents[_sender]);
    }

    _;
  }

  /**
   * Set the contract that can call release and make the token transferable.
   */
  function setReleaseAgent(address addr) onlyOwner inReleaseState(false) public {

    // We don't do interface check here as we might want to a normal wallet address to act as a release agent
    releaseAgent = addr;
  }

  /**
   * Owner can allow a particular address (a crowdsale contract) to transfer tokens despite the lock up period.
   */
  function setTransferAgent(address addr, bool state) onlyOwner inReleaseState(false) public {
    transferAgents[addr] = state;
  }

  /**
   * One way function to release the tokens to the wild.
   *
   * Can be called only from the release agent that is the final ICO contract. It is only called if the crowdsale has been success (first milestone reached).
   */
  function releaseTokenTransfer() public onlyReleaseAgent {
    released = true;
  }

  /** The function can be called only before or after the tokens have been releasesd */
  modifier inReleaseState(bool releaseState) {
    require(releaseState == released);
    _;
  }

  /** The function can be called only by a whitelisted release agent. */
  modifier onlyReleaseAgent() {
    require(msg.sender == releaseAgent);
    _;
  }


  function transfer(address _to, uint _value) canTransfer(msg.sender) returns (bool success) {
    // Call StandardToken.transfer()
   return super.transfer(_to, _value);
  }

  function transferFrom(address _from, address _to, uint _value) canTransfer(_from) returns (bool success) {
    // Call StandardToken.transferFrom()
    return super.transferFrom(_from, _to, _value);
  }

}


contract Coin is XinfinUpgradeableToken, ReleasableToken {

  event UpdatedTokenInformation(string newName, string newSymbol);

  /* name of the token */
  string public name = "XinFin XDCE";

  /* symbol of the token */
  string public symbol = "XDCE";

  /* token decimals to handle fractions */
  uint public decimals = 18;

  //Crowdsale running
  bool public isCrowdsaleOpen=false;

  /* initial token supply */
  uint public totalSupply = 15000000000 * (10 ** decimals);
  uint public onSaleTokens = 10000000000 * (10 ** decimals);


  uint tokensForPublicSale = 0;

  address contractAddress;

  uint256 pricePerToken = 7518796992481; //1 Eth = 133000 XDCE

  uint minETH = 0 * 10**decimals; // 0 ether
  uint maxETH = 15 * 10**decimals; // 15 ether

  function Coin() XinfinUpgradeableToken(msg.sender) {

    owner = msg.sender;
    contractAddress = address(this);
    //tokens are kept in contract address rather than owner
    balances[contractAddress] = totalSupply;
  }

  /* function to update token name and symbol */
  function updateTokenInformation(string _name, string _symbol) onlyOwner {
    name = _name;
    symbol = _symbol;
    UpdatedTokenInformation(name, symbol);
  }


  function sendTokensToOwner(uint _tokens) onlyOwner returns (bool ok){
      require(balances[contractAddress] >= _tokens);
      balances[contractAddress] = safeSub(balances[contractAddress],_tokens);
      balances[owner] = safeAdd(balances[owner],_tokens);
      return true;
  }


  /* single address */
  function sendTokensToInvestors(address _investor, uint _tokens) onlyOwner returns (bool ok){
      require(balances[contractAddress] >= _tokens);
      onSaleTokens = safeSub(onSaleTokens, _tokens);
      balances[contractAddress] = safeSub(balances[contractAddress],_tokens);
      balances[_investor] = safeAdd(balances[_investor],_tokens);
      return true;
  }



  /* A dispense feature to allocate some addresses with Xinfin tokens
  * calculation done using token count
  *  Can be called only by owner
  */
  function dispenseTokensToInvestorAddressesByValue(address[] _addresses, uint[] _value) onlyOwner returns (bool ok){
     require(_addresses.length == _value.length);
     for(uint256 i=0; i<_addresses.length; i++){
        onSaleTokens = safeSub(onSaleTokens, _value[i]);
        balances[_addresses[i]] = safeAdd(balances[_addresses[i]], _value[i]);
        balances[contractAddress] = safeSub(balances[contractAddress], _value[i]);
     }
     return true;
  }


  function startCrowdSale() onlyOwner {
     isCrowdsaleOpen=true;
  }

   function stopCrowdSale() onlyOwner {
     isCrowdsaleOpen=false;
  }


 function setPublicSaleParams(uint _tokensForPublicSale, uint _min, uint _max, bool _crowdsaleStatus ) onlyOwner {
    require(_tokensForPublicSale != 0);
    require(_tokensForPublicSale <= onSaleTokens);
    tokensForPublicSale = _tokensForPublicSale;
    isCrowdsaleOpen=_crowdsaleStatus;
    require(_min >= 0);
    require(_max > 0);
    minETH = _min;
    maxETH = _max;
 }


 function setTotalTokensForPublicSale(uint _value) onlyOwner{
      require(_value != 0);
      tokensForPublicSale = _value;
  }

 function increaseSupply(uint value) onlyOwner returns (bool) {
  totalSupply = safeAdd(totalSupply, value);
  balances[contractAddress] = safeAdd(balances[contractAddress], value);
  Transfer(0x0, contractAddress, value);
  return true;
}

function decreaseSupply(uint value) onlyOwner returns (bool) {
  balances[contractAddress] = safeSub(balances[contractAddress], value);
  totalSupply = safeSub(totalSupply, value);
  Transfer(contractAddress, 0x0, value);
  return true;
}

  function setMinAndMaxEthersForPublicSale(uint _min, uint _max) onlyOwner{
      require(_min >= 0);
      require(_max > 0);
      minETH = _min;
      maxETH = _max;
  }

  function updateTokenPrice(uint _value) onlyOwner{
      require(_value != 0);
      pricePerToken = _value;
  }


  function updateOnSaleSupply(uint _newSupply) onlyOwner{
      require(_newSupply != 0);
      onSaleTokens = _newSupply;
  }


  function buyTokens() public payable returns(uint tokenAmount) {

    uint _tokenAmount;
    uint multiplier = (10 ** decimals);
    uint weiAmount = msg.value;

    require(isCrowdsaleOpen);
    //require(whitelistedAddress[msg.sender]);

    require(weiAmount >= minETH);
    require(weiAmount <= maxETH);

    _tokenAmount =  safeMul(weiAmount,multiplier) / pricePerToken;

    require(_tokenAmount > 0);

    //safe sub will automatically handle overflows
    tokensForPublicSale = safeSub(tokensForPublicSale, _tokenAmount);
    onSaleTokens = safeSub(onSaleTokens, _tokenAmount);
    balances[contractAddress] = safeSub(balances[contractAddress],_tokenAmount);
    //assign tokens
    balances[msg.sender] = safeAdd(balances[msg.sender], _tokenAmount);

    //send money to the owner
    require(owner.send(weiAmount));

    return _tokenAmount;

  }

  // There is no need for vesting. It will be done manually by manually releasing tokens to certain addresses

  function() payable {
      buyTokens();
  }

  function destroyToken() public onlyOwner {
      selfdestruct(msg.sender);
  }

}

pragma solidity ^0.4.21;

/*
    Utilities & Common Modifiers
*/
contract Utils {
    /**
        constructor
    */
    function Utils() public {
    }

    // verifies that an amount is greater than zero
    modifier greaterThanZero(uint256 _amount) {
        require(_amount > 0);
        _;
    }

    // validates an address - currently only checks that it isn't null
    modifier validAddress(address _address) {
        require(_address != address(0));
        _;
    }

    // verifies that the address is different than this contract address
    modifier notThis(address _address) {
        require(_address != address(this));
        _;
    }

    // Overflow protected math functions

    /**
        @dev returns the sum of _x and _y, asserts if the calculation overflows

        @param _x   value 1
        @param _y   value 2

        @return sum
    */
    function safeAdd(uint256 _x, uint256 _y) internal pure returns (uint256) {
        uint256 z = _x + _y;
        assert(z >= _x);
        return z;
    }

    /**
        @dev returns the difference of _x minus _y, asserts if the subtraction results in a negative number

        @param _x   minuend
        @param _y   subtrahend

        @return difference
    */
    function safeSub(uint256 _x, uint256 _y) internal pure returns (uint256) {
        assert(_x >= _y);
        return _x - _y;
    }

    /**
        @dev returns the product of multiplying _x by _y, asserts if the calculation overflows

        @param _x   factor 1
        @param _y   factor 2

        @return product
    */
    function safeMul(uint256 _x, uint256 _y) internal pure returns (uint256) {
        uint256 z = _x * _y;
        assert(_x == 0 || z / _x == _y);
        return z;
    }
}

/*
    Bancor Formula interface
*/
contract IBancorFormula {
    function calculatePurchaseReturn(uint256 _supply, uint256 _connectorBalance, uint32 _connectorWeight, uint256 _depositAmount) public view returns (uint256);
    function calculateSaleReturn(uint256 _supply, uint256 _connectorBalance, uint32 _connectorWeight, uint256 _sellAmount) public view returns (uint256);
    function calculateCrossConnectorReturn(uint256 _fromConnectorBalance, uint32 _fromConnectorWeight, uint256 _toConnectorBalance, uint32 _toConnectorWeight, uint256 _amount) public view returns (uint256);
}

contract BancorFormula is IBancorFormula, Utils {
    string public version = '0.3';

    uint256 private constant ONE = 1;
    uint32 private constant MAX_WEIGHT = 1000000;
    uint8 private constant MIN_PRECISION = 32;
    uint8 private constant MAX_PRECISION = 127;

    /**
        Auto-generated via 'PrintIntScalingFactors.py'
    */
    uint256 private constant FIXED_1 = 0x080000000000000000000000000000000;
    uint256 private constant FIXED_2 = 0x100000000000000000000000000000000;
    uint256 private constant MAX_NUM = 0x200000000000000000000000000000000;

    /**
        Auto-generated via 'PrintLn2ScalingFactors.py'
    */
    uint256 private constant LN2_NUMERATOR   = 0x3f80fe03f80fe03f80fe03f80fe03f8;
    uint256 private constant LN2_DENOMINATOR = 0x5b9de1d10bf4103d647b0955897ba80;

    /**
        Auto-generated via 'PrintFunctionOptimalLog.py' and 'PrintFunctionOptimalExp.py'
    */
    uint256 private constant OPT_LOG_MAX_VAL = 0x15bf0a8b1457695355fb8ac404e7a79e3;
    uint256 private constant OPT_EXP_MAX_VAL = 0x800000000000000000000000000000000;

    /**
        Auto-generated via 'PrintFunctionBancorFormula.py'
    */
    uint256[128] private maxExpArray;
    function BancorFormula() public {
    //  maxExpArray[  0] = 0x6bffffffffffffffffffffffffffffffff;
    //  maxExpArray[  1] = 0x67ffffffffffffffffffffffffffffffff;
    //  maxExpArray[  2] = 0x637fffffffffffffffffffffffffffffff;
    //  maxExpArray[  3] = 0x5f6fffffffffffffffffffffffffffffff;
    //  maxExpArray[  4] = 0x5b77ffffffffffffffffffffffffffffff;
    //  maxExpArray[  5] = 0x57b3ffffffffffffffffffffffffffffff;
    //  maxExpArray[  6] = 0x5419ffffffffffffffffffffffffffffff;
    //  maxExpArray[  7] = 0x50a2ffffffffffffffffffffffffffffff;
    //  maxExpArray[  8] = 0x4d517fffffffffffffffffffffffffffff;
    //  maxExpArray[  9] = 0x4a233fffffffffffffffffffffffffffff;
    //  maxExpArray[ 10] = 0x47165fffffffffffffffffffffffffffff;
    //  maxExpArray[ 11] = 0x4429afffffffffffffffffffffffffffff;
    //  maxExpArray[ 12] = 0x415bc7ffffffffffffffffffffffffffff;
    //  maxExpArray[ 13] = 0x3eab73ffffffffffffffffffffffffffff;
    //  maxExpArray[ 14] = 0x3c1771ffffffffffffffffffffffffffff;
    //  maxExpArray[ 15] = 0x399e96ffffffffffffffffffffffffffff;
    //  maxExpArray[ 16] = 0x373fc47fffffffffffffffffffffffffff;
    //  maxExpArray[ 17] = 0x34f9e8ffffffffffffffffffffffffffff;
    //  maxExpArray[ 18] = 0x32cbfd5fffffffffffffffffffffffffff;
    //  maxExpArray[ 19] = 0x30b5057fffffffffffffffffffffffffff;
    //  maxExpArray[ 20] = 0x2eb40f9fffffffffffffffffffffffffff;
    //  maxExpArray[ 21] = 0x2cc8340fffffffffffffffffffffffffff;
    //  maxExpArray[ 22] = 0x2af09481ffffffffffffffffffffffffff;
    //  maxExpArray[ 23] = 0x292c5bddffffffffffffffffffffffffff;
    //  maxExpArray[ 24] = 0x277abdcdffffffffffffffffffffffffff;
    //  maxExpArray[ 25] = 0x25daf6657fffffffffffffffffffffffff;
    //  maxExpArray[ 26] = 0x244c49c65fffffffffffffffffffffffff;
    //  maxExpArray[ 27] = 0x22ce03cd5fffffffffffffffffffffffff;
    //  maxExpArray[ 28] = 0x215f77c047ffffffffffffffffffffffff;
    //  maxExpArray[ 29] = 0x1fffffffffffffffffffffffffffffffff;
    //  maxExpArray[ 30] = 0x1eaefdbdabffffffffffffffffffffffff;
    //  maxExpArray[ 31] = 0x1d6bd8b2ebffffffffffffffffffffffff;
        maxExpArray[ 32] = 0x1c35fedd14ffffffffffffffffffffffff;
        maxExpArray[ 33] = 0x1b0ce43b323fffffffffffffffffffffff;
        maxExpArray[ 34] = 0x19f0028ec1ffffffffffffffffffffffff;
        maxExpArray[ 35] = 0x18ded91f0e7fffffffffffffffffffffff;
        maxExpArray[ 36] = 0x17d8ec7f0417ffffffffffffffffffffff;
        maxExpArray[ 37] = 0x16ddc6556cdbffffffffffffffffffffff;
        maxExpArray[ 38] = 0x15ecf52776a1ffffffffffffffffffffff;
        maxExpArray[ 39] = 0x15060c256cb2ffffffffffffffffffffff;
        maxExpArray[ 40] = 0x1428a2f98d72ffffffffffffffffffffff;
        maxExpArray[ 41] = 0x13545598e5c23fffffffffffffffffffff;
        maxExpArray[ 42] = 0x1288c4161ce1dfffffffffffffffffffff;
        maxExpArray[ 43] = 0x11c592761c666fffffffffffffffffffff;
        maxExpArray[ 44] = 0x110a688680a757ffffffffffffffffffff;
        maxExpArray[ 45] = 0x1056f1b5bedf77ffffffffffffffffffff;
        maxExpArray[ 46] = 0x0faadceceeff8bffffffffffffffffffff;
        maxExpArray[ 47] = 0x0f05dc6b27edadffffffffffffffffffff;
        maxExpArray[ 48] = 0x0e67a5a25da4107fffffffffffffffffff;
        maxExpArray[ 49] = 0x0dcff115b14eedffffffffffffffffffff;
        maxExpArray[ 50] = 0x0d3e7a392431239fffffffffffffffffff;
        maxExpArray[ 51] = 0x0cb2ff529eb71e4fffffffffffffffffff;
        maxExpArray[ 52] = 0x0c2d415c3db974afffffffffffffffffff;
        maxExpArray[ 53] = 0x0bad03e7d883f69bffffffffffffffffff;
        maxExpArray[ 54] = 0x0b320d03b2c343d5ffffffffffffffffff;
        maxExpArray[ 55] = 0x0abc25204e02828dffffffffffffffffff;
        maxExpArray[ 56] = 0x0a4b16f74ee4bb207fffffffffffffffff;
        maxExpArray[ 57] = 0x09deaf736ac1f569ffffffffffffffffff;
        maxExpArray[ 58] = 0x0976bd9952c7aa957fffffffffffffffff;
        maxExpArray[ 59] = 0x09131271922eaa606fffffffffffffffff;
        maxExpArray[ 60] = 0x08b380f3558668c46fffffffffffffffff;
        maxExpArray[ 61] = 0x0857ddf0117efa215bffffffffffffffff;
        maxExpArray[ 62] = 0x07ffffffffffffffffffffffffffffffff;
        maxExpArray[ 63] = 0x07abbf6f6abb9d087fffffffffffffffff;
        maxExpArray[ 64] = 0x075af62cbac95f7dfa7fffffffffffffff;
        maxExpArray[ 65] = 0x070d7fb7452e187ac13fffffffffffffff;
        maxExpArray[ 66] = 0x06c3390ecc8af379295fffffffffffffff;
        maxExpArray[ 67] = 0x067c00a3b07ffc01fd6fffffffffffffff;
        maxExpArray[ 68] = 0x0637b647c39cbb9d3d27ffffffffffffff;
        maxExpArray[ 69] = 0x05f63b1fc104dbd39587ffffffffffffff;
        maxExpArray[ 70] = 0x05b771955b36e12f7235ffffffffffffff;
        maxExpArray[ 71] = 0x057b3d49dda84556d6f6ffffffffffffff;
        maxExpArray[ 72] = 0x054183095b2c8ececf30ffffffffffffff;
        maxExpArray[ 73] = 0x050a28be635ca2b888f77fffffffffffff;
        maxExpArray[ 74] = 0x04d5156639708c9db33c3fffffffffffff;
        maxExpArray[ 75] = 0x04a23105873875bd52dfdfffffffffffff;
        maxExpArray[ 76] = 0x0471649d87199aa990756fffffffffffff;
        maxExpArray[ 77] = 0x04429a21a029d4c1457cfbffffffffffff;
        maxExpArray[ 78] = 0x0415bc6d6fb7dd71af2cb3ffffffffffff;
        maxExpArray[ 79] = 0x03eab73b3bbfe282243ce1ffffffffffff;
        maxExpArray[ 80] = 0x03c1771ac9fb6b4c18e229ffffffffffff;
        maxExpArray[ 81] = 0x0399e96897690418f785257fffffffffff;
        maxExpArray[ 82] = 0x0373fc456c53bb779bf0ea9fffffffffff;
        maxExpArray[ 83] = 0x034f9e8e490c48e67e6ab8bfffffffffff;
        maxExpArray[ 84] = 0x032cbfd4a7adc790560b3337ffffffffff;
        maxExpArray[ 85] = 0x030b50570f6e5d2acca94613ffffffffff;
        maxExpArray[ 86] = 0x02eb40f9f620fda6b56c2861ffffffffff;
        maxExpArray[ 87] = 0x02cc8340ecb0d0f520a6af58ffffffffff;
        maxExpArray[ 88] = 0x02af09481380a0a35cf1ba02ffffffffff;
        maxExpArray[ 89] = 0x0292c5bdd3b92ec810287b1b3fffffffff;
        maxExpArray[ 90] = 0x0277abdcdab07d5a77ac6d6b9fffffffff;
        maxExpArray[ 91] = 0x025daf6654b1eaa55fd64df5efffffffff;
        maxExpArray[ 92] = 0x0244c49c648baa98192dce88b7ffffffff;
        maxExpArray[ 93] = 0x022ce03cd5619a311b2471268bffffffff;
        maxExpArray[ 94] = 0x0215f77c045fbe885654a44a0fffffffff;
        maxExpArray[ 95] = 0x01ffffffffffffffffffffffffffffffff;
        maxExpArray[ 96] = 0x01eaefdbdaaee7421fc4d3ede5ffffffff;
        maxExpArray[ 97] = 0x01d6bd8b2eb257df7e8ca57b09bfffffff;
        maxExpArray[ 98] = 0x01c35fedd14b861eb0443f7f133fffffff;
        maxExpArray[ 99] = 0x01b0ce43b322bcde4a56e8ada5afffffff;
        maxExpArray[100] = 0x019f0028ec1fff007f5a195a39dfffffff;
        maxExpArray[101] = 0x018ded91f0e72ee74f49b15ba527ffffff;
        maxExpArray[102] = 0x017d8ec7f04136f4e5615fd41a63ffffff;
        maxExpArray[103] = 0x016ddc6556cdb84bdc8d12d22e6fffffff;
        maxExpArray[104] = 0x015ecf52776a1155b5bd8395814f7fffff;
        maxExpArray[105] = 0x015060c256cb23b3b3cc3754cf40ffffff;
        maxExpArray[106] = 0x01428a2f98d728ae223ddab715be3fffff;
        maxExpArray[107] = 0x013545598e5c23276ccf0ede68034fffff;
        maxExpArray[108] = 0x01288c4161ce1d6f54b7f61081194fffff;
        maxExpArray[109] = 0x011c592761c666aa641d5a01a40f17ffff;
        maxExpArray[110] = 0x0110a688680a7530515f3e6e6cfdcdffff;
        maxExpArray[111] = 0x01056f1b5bedf75c6bcb2ce8aed428ffff;
        maxExpArray[112] = 0x00faadceceeff8a0890f3875f008277fff;
        maxExpArray[113] = 0x00f05dc6b27edad306388a600f6ba0bfff;
        maxExpArray[114] = 0x00e67a5a25da41063de1495d5b18cdbfff;
        maxExpArray[115] = 0x00dcff115b14eedde6fc3aa5353f2e4fff;
        maxExpArray[116] = 0x00d3e7a3924312399f9aae2e0f868f8fff;
        maxExpArray[117] = 0x00cb2ff529eb71e41582cccd5a1ee26fff;
        maxExpArray[118] = 0x00c2d415c3db974ab32a51840c0b67edff;
        maxExpArray[119] = 0x00bad03e7d883f69ad5b0a186184e06bff;
        maxExpArray[120] = 0x00b320d03b2c343d4829abd6075f0cc5ff;
        maxExpArray[121] = 0x00abc25204e02828d73c6e80bcdb1a95bf;
        maxExpArray[122] = 0x00a4b16f74ee4bb2040a1ec6c15fbbf2df;
        maxExpArray[123] = 0x009deaf736ac1f569deb1b5ae3f36c130f;
        maxExpArray[124] = 0x00976bd9952c7aa957f5937d790ef65037;
        maxExpArray[125] = 0x009131271922eaa6064b73a22d0bd4f2bf;
        maxExpArray[126] = 0x008b380f3558668c46c91c49a2f8e967b9;
        maxExpArray[127] = 0x00857ddf0117efa215952912839f6473e6;
    }

    /**
        @dev given a token supply, connector balance, weight and a deposit amount (in the connector token),
        calculates the return for a given conversion (in the main token)

        Formula:
        Return = _supply * ((1 + _depositAmount / _connectorBalance) ^ (_connectorWeight / 1000000) - 1)

        @param _supply              token total supply
        @param _connectorBalance    total connector balance
        @param _connectorWeight     connector weight, represented in ppm, 1-1000000
        @param _depositAmount       deposit amount, in connector token

        @return purchase return amount
    */
    function calculatePurchaseReturn(uint256 _supply, uint256 _connectorBalance, uint32 _connectorWeight, uint256 _depositAmount) public view returns (uint256) {
        // validate input
        require(_supply > 0 && _connectorBalance > 0 && _connectorWeight > 0 && _connectorWeight <= MAX_WEIGHT);

        // special case for 0 deposit amount
        if (_depositAmount == 0)
            return 0;

        // special case if the weight = 100%
        if (_connectorWeight == MAX_WEIGHT)
            return safeMul(_supply, _depositAmount) / _connectorBalance;

        uint256 result;
        uint8 precision;
        uint256 baseN = safeAdd(_depositAmount, _connectorBalance);
        (result, precision) = power(baseN, _connectorBalance, _connectorWeight, MAX_WEIGHT);
        uint256 temp = safeMul(_supply, result) >> precision;
        return temp - _supply;
    }

    /**
        @dev given a token supply, connector balance, weight and a sell amount (in the main token),
        calculates the return for a given conversion (in the connector token)

        Formula:
        Return = _connectorBalance * (1 - (1 - _sellAmount / _supply) ^ (1 / (_connectorWeight / 1000000)))

        @param _supply              token total supply
        @param _connectorBalance    total connector
        @param _connectorWeight     constant connector Weight, represented in ppm, 1-1000000
        @param _sellAmount          sell amount, in the token itself

        @return sale return amount
    */
    function calculateSaleReturn(uint256 _supply, uint256 _connectorBalance, uint32 _connectorWeight, uint256 _sellAmount) public view returns (uint256) {
        // validate input
        require(_supply > 0 && _connectorBalance > 0 && _connectorWeight > 0 && _connectorWeight <= MAX_WEIGHT && _sellAmount <= _supply);

        // special case for 0 sell amount
        if (_sellAmount == 0)
            return 0;

        // special case for selling the entire supply
        if (_sellAmount == _supply)
            return _connectorBalance;

        // special case if the weight = 100%
        if (_connectorWeight == MAX_WEIGHT)
            return safeMul(_connectorBalance, _sellAmount) / _supply;

        uint256 result;
        uint8 precision;
        uint256 baseD = _supply - _sellAmount;
        (result, precision) = power(_supply, baseD, MAX_WEIGHT, _connectorWeight);
        uint256 temp1 = safeMul(_connectorBalance, result);
        uint256 temp2 = _connectorBalance << precision;
        return (temp1 - temp2) / result;
    }

    /**
        @dev given two connector balances/weights and a sell amount (in the first connector token),
        calculates the return for a conversion from the first connector token to the second connector token (in the second connector token)

        Formula:
        Return = _toConnectorBalance * (1 - (_fromConnectorBalance / (_fromConnectorBalance + _amount)) ^ (_fromConnectorWeight / _toConnectorWeight))

        @param _fromConnectorBalance    input connector balance
        @param _fromConnectorWeight     input connector weight, represented in ppm, 1-1000000
        @param _toConnectorBalance      output connector balance
        @param _toConnectorWeight       output connector weight, represented in ppm, 1-1000000
        @param _amount                  input connector amount

        @return second connector amount
    */
    function calculateCrossConnectorReturn(uint256 _fromConnectorBalance, uint32 _fromConnectorWeight, uint256 _toConnectorBalance, uint32 _toConnectorWeight, uint256 _amount) public view returns (uint256) {
        // validate input
        require(_fromConnectorBalance > 0 && _fromConnectorWeight > 0 && _fromConnectorWeight <= MAX_WEIGHT && _toConnectorBalance > 0 && _toConnectorWeight > 0 && _toConnectorWeight <= MAX_WEIGHT);

        // special case for equal weights
        if (_fromConnectorWeight == _toConnectorWeight)
            return safeMul(_toConnectorBalance, _amount) / safeAdd(_fromConnectorBalance, _amount);

        uint256 result;
        uint8 precision;
        uint256 baseN = safeAdd(_fromConnectorBalance, _amount);
        (result, precision) = power(baseN, _fromConnectorBalance, _fromConnectorWeight, _toConnectorWeight);
        uint256 temp1 = safeMul(_toConnectorBalance, result);
        uint256 temp2 = _toConnectorBalance << precision;
        return (temp1 - temp2) / result;
    }

    /**
        General Description:
            Determine a value of precision.
            Calculate an integer approximation of (_baseN / _baseD) ^ (_expN / _expD) * 2 ^ precision.
            Return the result along with the precision used.

        Detailed Description:
            Instead of calculating "base ^ exp", we calculate "e ^ (log(base) * exp)".
            The value of "log(base)" is represented with an integer slightly smaller than "log(base) * 2 ^ precision".
            The larger "precision" is, the more accurately this value represents the real value.
            However, the larger "precision" is, the more bits are required in order to store this value.
            And the exponentiation function, which takes "x" and calculates "e ^ x", is limited to a maximum exponent (maximum value of "x").
            This maximum exponent depends on the "precision" used, and it is given by "maxExpArray[precision] >> (MAX_PRECISION - precision)".
            Hence we need to determine the highest precision which can be used for the given input, before calling the exponentiation function.
            This allows us to compute "base ^ exp" with maximum accuracy and without exceeding 256 bits in any of the intermediate computations.
            This functions assumes that "_expN < 2 ^ 256 / log(MAX_NUM - 1)", otherwise the multiplication should be replaced with a "safeMul".
    */
    function power(uint256 _baseN, uint256 _baseD, uint32 _expN, uint32 _expD) internal view returns (uint256, uint8) {
        assert(_baseN < MAX_NUM);

        uint256 baseLog;
        uint256 base = _baseN * FIXED_1 / _baseD;
        if (base < OPT_LOG_MAX_VAL) {
            baseLog = optimalLog(base);
        }
        else {
            baseLog = generalLog(base);
        }

        uint256 baseLogTimesExp = baseLog * _expN / _expD;
        if (baseLogTimesExp < OPT_EXP_MAX_VAL) {
            return (optimalExp(baseLogTimesExp), MAX_PRECISION);
        }
        else {
            uint8 precision = findPositionInMaxExpArray(baseLogTimesExp);
            return (generalExp(baseLogTimesExp >> (MAX_PRECISION - precision), precision), precision);
        }
    }

    /**
        Compute log(x / FIXED_1) * FIXED_1.
        This functions assumes that "x >= FIXED_1", because the output would be negative otherwise.
    */
    function generalLog(uint256 x) internal pure returns (uint256) {
        uint256 res = 0;

        // If x >= 2, then we compute the integer part of log2(x), which is larger than 0.
        if (x >= FIXED_2) {
            uint8 count = floorLog2(x / FIXED_1);
            x >>= count; // now x < 2
            res = count * FIXED_1;
        }

        // If x > 1, then we compute the fraction part of log2(x), which is larger than 0.
        if (x > FIXED_1) {
            for (uint8 i = MAX_PRECISION; i > 0; --i) {
                x = (x * x) / FIXED_1; // now 1 < x < 4
                if (x >= FIXED_2) {
                    x >>= 1; // now 1 < x < 2
                    res += ONE << (i - 1);
                }
            }
        }

        return res * LN2_NUMERATOR / LN2_DENOMINATOR;
    }

    /**
        Compute the largest integer smaller than or equal to the binary logarithm of the input.
    */
    function floorLog2(uint256 _n) internal pure returns (uint8) {
        uint8 res = 0;

        if (_n < 256) {
            // At most 8 iterations
            while (_n > 1) {
                _n >>= 1;
                res += 1;
            }
        }
        else {
            // Exactly 8 iterations
            for (uint8 s = 128; s > 0; s >>= 1) {
                if (_n >= (ONE << s)) {
                    _n >>= s;
                    res |= s;
                }
            }
        }

        return res;
    }

    /**
        The global "maxExpArray" is sorted in descending order, and therefore the following statements are equivalent:
        - This function finds the position of [the smallest value in "maxExpArray" larger than or equal to "x"]
        - This function finds the highest position of [a value in "maxExpArray" larger than or equal to "x"]
    */
    function findPositionInMaxExpArray(uint256 _x) internal view returns (uint8) {
        uint8 lo = MIN_PRECISION;
        uint8 hi = MAX_PRECISION;

        while (lo + 1 < hi) {
            uint8 mid = (lo + hi) / 2;
            if (maxExpArray[mid] >= _x)
                lo = mid;
            else
                hi = mid;
        }

        if (maxExpArray[hi] >= _x)
            return hi;
        if (maxExpArray[lo] >= _x)
            return lo;

        assert(false);
        return 0;
    }

    /**
        This function can be auto-generated by the script 'PrintFunctionGeneralExp.py'.
        It approximates "e ^ x" via maclaurin summation: "(x^0)/0! + (x^1)/1! + ... + (x^n)/n!".
        It returns "e ^ (x / 2 ^ precision) * 2 ^ precision", that is, the result is upshifted for accuracy.
        The global "maxExpArray" maps each "precision" to "((maximumExponent + 1) << (MAX_PRECISION - precision)) - 1".
        The maximum permitted value for "x" is therefore given by "maxExpArray[precision] >> (MAX_PRECISION - precision)".
    */
    function generalExp(uint256 _x, uint8 _precision) internal pure returns (uint256) {
        uint256 xi = _x;
        uint256 res = 0;

        xi = (xi * _x) >> _precision; res += xi * 0x3442c4e6074a82f1797f72ac0000000; // add x^02 * (33! / 02!)
        xi = (xi * _x) >> _precision; res += xi * 0x116b96f757c380fb287fd0e40000000; // add x^03 * (33! / 03!)
        xi = (xi * _x) >> _precision; res += xi * 0x045ae5bdd5f0e03eca1ff4390000000; // add x^04 * (33! / 04!)
        xi = (xi * _x) >> _precision; res += xi * 0x00defabf91302cd95b9ffda50000000; // add x^05 * (33! / 05!)
        xi = (xi * _x) >> _precision; res += xi * 0x002529ca9832b22439efff9b8000000; // add x^06 * (33! / 06!)
        xi = (xi * _x) >> _precision; res += xi * 0x00054f1cf12bd04e516b6da88000000; // add x^07 * (33! / 07!)
        xi = (xi * _x) >> _precision; res += xi * 0x0000a9e39e257a09ca2d6db51000000; // add x^08 * (33! / 08!)
        xi = (xi * _x) >> _precision; res += xi * 0x000012e066e7b839fa050c309000000; // add x^09 * (33! / 09!)
        xi = (xi * _x) >> _precision; res += xi * 0x000001e33d7d926c329a1ad1a800000; // add x^10 * (33! / 10!)
        xi = (xi * _x) >> _precision; res += xi * 0x0000002bee513bdb4a6b19b5f800000; // add x^11 * (33! / 11!)
        xi = (xi * _x) >> _precision; res += xi * 0x00000003a9316fa79b88eccf2a00000; // add x^12 * (33! / 12!)
        xi = (xi * _x) >> _precision; res += xi * 0x0000000048177ebe1fa812375200000; // add x^13 * (33! / 13!)
        xi = (xi * _x) >> _precision; res += xi * 0x0000000005263fe90242dcbacf00000; // add x^14 * (33! / 14!)
        xi = (xi * _x) >> _precision; res += xi * 0x000000000057e22099c030d94100000; // add x^15 * (33! / 15!)
        xi = (xi * _x) >> _precision; res += xi * 0x0000000000057e22099c030d9410000; // add x^16 * (33! / 16!)
        xi = (xi * _x) >> _precision; res += xi * 0x00000000000052b6b54569976310000; // add x^17 * (33! / 17!)
        xi = (xi * _x) >> _precision; res += xi * 0x00000000000004985f67696bf748000; // add x^18 * (33! / 18!)
        xi = (xi * _x) >> _precision; res += xi * 0x000000000000003dea12ea99e498000; // add x^19 * (33! / 19!)
        xi = (xi * _x) >> _precision; res += xi * 0x00000000000000031880f2214b6e000; // add x^20 * (33! / 20!)
        xi = (xi * _x) >> _precision; res += xi * 0x000000000000000025bcff56eb36000; // add x^21 * (33! / 21!)
        xi = (xi * _x) >> _precision; res += xi * 0x000000000000000001b722e10ab1000; // add x^22 * (33! / 22!)
        xi = (xi * _x) >> _precision; res += xi * 0x0000000000000000001317c70077000; // add x^23 * (33! / 23!)
        xi = (xi * _x) >> _precision; res += xi * 0x00000000000000000000cba84aafa00; // add x^24 * (33! / 24!)
        xi = (xi * _x) >> _precision; res += xi * 0x00000000000000000000082573a0a00; // add x^25 * (33! / 25!)
        xi = (xi * _x) >> _precision; res += xi * 0x00000000000000000000005035ad900; // add x^26 * (33! / 26!)
        xi = (xi * _x) >> _precision; res += xi * 0x000000000000000000000002f881b00; // add x^27 * (33! / 27!)
        xi = (xi * _x) >> _precision; res += xi * 0x0000000000000000000000001b29340; // add x^28 * (33! / 28!)
        xi = (xi * _x) >> _precision; res += xi * 0x00000000000000000000000000efc40; // add x^29 * (33! / 29!)
        xi = (xi * _x) >> _precision; res += xi * 0x0000000000000000000000000007fe0; // add x^30 * (33! / 30!)
        xi = (xi * _x) >> _precision; res += xi * 0x0000000000000000000000000000420; // add x^31 * (33! / 31!)
        xi = (xi * _x) >> _precision; res += xi * 0x0000000000000000000000000000021; // add x^32 * (33! / 32!)
        xi = (xi * _x) >> _precision; res += xi * 0x0000000000000000000000000000001; // add x^33 * (33! / 33!)

        return res / 0x688589cc0e9505e2f2fee5580000000 + _x + (ONE << _precision); // divide by 33! and then add x^1 / 1! + x^0 / 0!
    }

    /**
        Return log(x / FIXED_1) * FIXED_1
        Input range: FIXED_1 <= x <= LOG_EXP_MAX_VAL - 1
        Auto-generated via 'PrintFunctionOptimalLog.py'
    */
    function optimalLog(uint256 x) internal pure returns (uint256) {
        uint256 res = 0;

        uint256 y;
        uint256 z;
        uint256 w;

        if (x >= 0xd3094c70f034de4b96ff7d5b6f99fcd8) {res += 0x40000000000000000000000000000000; x = x * FIXED_1 / 0xd3094c70f034de4b96ff7d5b6f99fcd8;}
        if (x >= 0xa45af1e1f40c333b3de1db4dd55f29a7) {res += 0x20000000000000000000000000000000; x = x * FIXED_1 / 0xa45af1e1f40c333b3de1db4dd55f29a7;}
        if (x >= 0x910b022db7ae67ce76b441c27035c6a1) {res += 0x10000000000000000000000000000000; x = x * FIXED_1 / 0x910b022db7ae67ce76b441c27035c6a1;}
        if (x >= 0x88415abbe9a76bead8d00cf112e4d4a8) {res += 0x08000000000000000000000000000000; x = x * FIXED_1 / 0x88415abbe9a76bead8d00cf112e4d4a8;}
        if (x >= 0x84102b00893f64c705e841d5d4064bd3) {res += 0x04000000000000000000000000000000; x = x * FIXED_1 / 0x84102b00893f64c705e841d5d4064bd3;}
        if (x >= 0x8204055aaef1c8bd5c3259f4822735a2) {res += 0x02000000000000000000000000000000; x = x * FIXED_1 / 0x8204055aaef1c8bd5c3259f4822735a2;}
        if (x >= 0x810100ab00222d861931c15e39b44e99) {res += 0x01000000000000000000000000000000; x = x * FIXED_1 / 0x810100ab00222d861931c15e39b44e99;}
        if (x >= 0x808040155aabbbe9451521693554f733) {res += 0x00800000000000000000000000000000; x = x * FIXED_1 / 0x808040155aabbbe9451521693554f733;}

        z = y = x - FIXED_1;
        w = y * y / FIXED_1;
        res += z * (0x100000000000000000000000000000000 - y) / 0x100000000000000000000000000000000; z = z * w / FIXED_1;
        res += z * (0x0aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa - y) / 0x200000000000000000000000000000000; z = z * w / FIXED_1;
        res += z * (0x099999999999999999999999999999999 - y) / 0x300000000000000000000000000000000; z = z * w / FIXED_1;
        res += z * (0x092492492492492492492492492492492 - y) / 0x400000000000000000000000000000000; z = z * w / FIXED_1;
        res += z * (0x08e38e38e38e38e38e38e38e38e38e38e - y) / 0x500000000000000000000000000000000; z = z * w / FIXED_1;
        res += z * (0x08ba2e8ba2e8ba2e8ba2e8ba2e8ba2e8b - y) / 0x600000000000000000000000000000000; z = z * w / FIXED_1;
        res += z * (0x089d89d89d89d89d89d89d89d89d89d89 - y) / 0x700000000000000000000000000000000; z = z * w / FIXED_1;
        res += z * (0x088888888888888888888888888888888 - y) / 0x800000000000000000000000000000000;

        return res;
    }

    /**
        Return e ^ (x / FIXED_1) * FIXED_1
        Input range: 0 <= x <= OPT_EXP_MAX_VAL - 1
        Auto-generated via 'PrintFunctionOptimalExp.py'
    */
    function optimalExp(uint256 x) internal pure returns (uint256) {
        uint256 res = 0;

        uint256 y;
        uint256 z;

        z = y = x % 0x10000000000000000000000000000000;
        z = z * y / FIXED_1; res += z * 0x10e1b3be415a0000; // add y^02 * (20! / 02!)
        z = z * y / FIXED_1; res += z * 0x05a0913f6b1e0000; // add y^03 * (20! / 03!)
        z = z * y / FIXED_1; res += z * 0x0168244fdac78000; // add y^04 * (20! / 04!)
        z = z * y / FIXED_1; res += z * 0x004807432bc18000; // add y^05 * (20! / 05!)
        z = z * y / FIXED_1; res += z * 0x000c0135dca04000; // add y^06 * (20! / 06!)
        z = z * y / FIXED_1; res += z * 0x0001b707b1cdc000; // add y^07 * (20! / 07!)
        z = z * y / FIXED_1; res += z * 0x000036e0f639b800; // add y^08 * (20! / 08!)
        z = z * y / FIXED_1; res += z * 0x00000618fee9f800; // add y^09 * (20! / 09!)
        z = z * y / FIXED_1; res += z * 0x0000009c197dcc00; // add y^10 * (20! / 10!)
        z = z * y / FIXED_1; res += z * 0x0000000e30dce400; // add y^11 * (20! / 11!)
        z = z * y / FIXED_1; res += z * 0x000000012ebd1300; // add y^12 * (20! / 12!)
        z = z * y / FIXED_1; res += z * 0x0000000017499f00; // add y^13 * (20! / 13!)
        z = z * y / FIXED_1; res += z * 0x0000000001a9d480; // add y^14 * (20! / 14!)
        z = z * y / FIXED_1; res += z * 0x00000000001c6380; // add y^15 * (20! / 15!)
        z = z * y / FIXED_1; res += z * 0x000000000001c638; // add y^16 * (20! / 16!)
        z = z * y / FIXED_1; res += z * 0x0000000000001ab8; // add y^17 * (20! / 17!)
        z = z * y / FIXED_1; res += z * 0x000000000000017c; // add y^18 * (20! / 18!)
        z = z * y / FIXED_1; res += z * 0x0000000000000014; // add y^19 * (20! / 19!)
        z = z * y / FIXED_1; res += z * 0x0000000000000001; // add y^20 * (20! / 20!)
        res = res / 0x21c3677c82b40000 + y + FIXED_1; // divide by 20! and then add y^1 / 1! + y^0 / 0!

        if ((x & 0x010000000000000000000000000000000) != 0) res = res * 0x1c3d6a24ed82218787d624d3e5eba95f9 / 0x18ebef9eac820ae8682b9793ac6d1e776;
        if ((x & 0x020000000000000000000000000000000) != 0) res = res * 0x18ebef9eac820ae8682b9793ac6d1e778 / 0x1368b2fc6f9609fe7aceb46aa619baed4;
        if ((x & 0x040000000000000000000000000000000) != 0) res = res * 0x1368b2fc6f9609fe7aceb46aa619baed5 / 0x0bc5ab1b16779be3575bd8f0520a9f21f;
        if ((x & 0x080000000000000000000000000000000) != 0) res = res * 0x0bc5ab1b16779be3575bd8f0520a9f21e / 0x0454aaa8efe072e7f6ddbab84b40a55c9;
        if ((x & 0x100000000000000000000000000000000) != 0) res = res * 0x0454aaa8efe072e7f6ddbab84b40a55c5 / 0x00960aadc109e7a3bf4578099615711ea;
        if ((x & 0x200000000000000000000000000000000) != 0) res = res * 0x00960aadc109e7a3bf4578099615711d7 / 0x0002bf84208204f5977f9a8cf01fdce3d;
        if ((x & 0x400000000000000000000000000000000) != 0) res = res * 0x0002bf84208204f5977f9a8cf01fdc307 / 0x0000003c6ab775dd0b95b4cbee7e65d11;

        return res;
    }
}