Contract Name:
MasterToken
Contract Source Code:
pragma solidity ^0.7.4;
// "SPDX-License-Identifier: Apache License 2.0"
import "./IERC20.sol";
import "./SafeMath.sol";
/**
* @title Standard ERC20 token
*
* @dev Implementation of the basic standard token.
* https://github.com/ethereum/EIPs/blob/master/EIPS/eip-20.md
* Originally based on code by FirstBlood:
* https://github.com/Firstbloodio/token/blob/master/smart_contract/FirstBloodToken.sol
*
* This implementation emits additional Approval events, allowing applications to reconstruct the allowance status for
* all accounts just by listening to said events. Note that this isn't required by the specification, and other
* compliant implementations may not do it.
*/
contract ERC20 is IERC20 {
using SafeMath for uint256;
mapping(address => uint256) private _balances;
mapping(address => mapping(address => uint256)) private _allowed;
uint256 private _totalSupply;
/**
* @dev Total number of tokens in existence
*/
function totalSupply() public view override returns (uint256) {
return _totalSupply;
}
/**
* @dev Gets the balance of the specified address.
* @param owner The address to query the balance of.
* @return An uint256 representing the amount owned by the passed address.
*/
function balanceOf(address owner) public view override returns (uint256) {
return _balances[owner];
}
/**
* @dev Function to check the amount of tokens that an owner allowed to a spender.
* @param owner address The address which owns the funds.
* @param spender address The address which will spend the funds.
* @return A uint256 specifying the amount of tokens still available for the spender.
*/
function allowance(address owner, address spender) public view override returns (uint256) {
return _allowed[owner][spender];
}
/**
* @dev Transfer token for a specified address
* @param to The address to transfer to.
* @param value The amount to be transferred.
*/
function transfer(address to, uint256 value) public override returns (bool) {
_transfer(msg.sender, to, value);
return true;
}
/**
* @dev Approve the passed address to spend the specified amount of tokens on behalf of msg.sender.
* Beware that changing an allowance with this method brings the risk that someone may use both the old
* and the new allowance by unfortunate transaction ordering. One possible solution to mitigate this
* race condition is to first reduce the spender's allowance to 0 and set the desired value afterwards:
* https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
* @param spender The address which will spend the funds.
* @param value The amount of tokens to be spent.
*/
function approve(address spender, uint256 value) public override returns (bool) {
_approve(msg.sender, spender, value);
return true;
}
/**
* @dev Transfer tokens from one address to another.
* Note that while this function emits an Approval event, this is not required as per the specification,
* and other compliant implementations may not emit the event.
* @param from address The address which you want to send tokens from
* @param to address The address which you want to transfer to
* @param value uint256 the amount of tokens to be transferred
*/
function transferFrom(address from, address to, uint256 value) public override returns (bool) {
_transfer(from, to, value);
_approve(from, msg.sender, _allowed[from][msg.sender].sub(value));
return true;
}
/**
* @dev Increase the amount of tokens that an owner allowed to a spender.
* approve should be called when allowed_[_spender] == 0. To increment
* allowed value is better to use this function to avoid 2 calls (and wait until
* the first transaction is mined)
* From MonolithDAO Token.sol
* Emits an Approval event.
* @param spender The address which will spend the funds.
* @param addedValue The amount of tokens to increase the allowance by.
*/
function increaseAllowance(address spender, uint256 addedValue) public returns (bool) {
_approve(msg.sender, spender, _allowed[msg.sender][spender].add(addedValue));
return true;
}
/**
* @dev Decrease the amount of tokens that an owner allowed to a spender.
* approve should be called when allowed_[_spender] == 0. To decrement
* allowed value is better to use this function to avoid 2 calls (and wait until
* the first transaction is mined)
* From MonolithDAO Token.sol
* Emits an Approval event.
* @param spender The address which will spend the funds.
* @param subtractedValue The amount of tokens to decrease the allowance by.
*/
function decreaseAllowance(address spender, uint256 subtractedValue) public returns (bool) {
_approve(msg.sender, spender, _allowed[msg.sender][spender].sub(subtractedValue));
return true;
}
/**
* @dev Transfer token for a specified addresses
* @param from The address to transfer from.
* @param to The address to transfer to.
* @param value The amount to be transferred.
*/
function _transfer(address from, address to, uint256 value) internal {
require(to != address(0));
_balances[from] = _balances[from].sub(value);
_balances[to] = _balances[to].add(value);
emit Transfer(from, to, value);
}
/**
* @dev Internal function that mints an amount of the token and assigns it to
* an account. This encapsulates the modification of balances such that the
* proper events are emitted.
* @param account The account that will receive the created tokens.
* @param value The amount that will be created.
*/
function _mint(address account, uint256 value) internal {
require(account != address(0));
_totalSupply = _totalSupply.add(value);
_balances[account] = _balances[account].add(value);
emit Transfer(address(0), account, value);
}
/**
* @dev Internal function that burns an amount of the token of a given
* account.
* @param account The account whose tokens will be burnt.
* @param value The amount that will be burnt.
*/
function _burn(address account, uint256 value) internal {
require(account != address(0));
_totalSupply = _totalSupply.sub(value);
_balances[account] = _balances[account].sub(value);
emit Transfer(account, address(0), value);
}
/**
* @dev Approve an address to spend another addresses' tokens.
* @param owner The address that owns the tokens.
* @param spender The address that will spend the tokens.
* @param value The number of tokens that can be spent.
*/
function _approve(address owner, address spender, uint256 value) internal {
require(spender != address(0));
require(owner != address(0));
_allowed[owner][spender] = value;
emit Approval(owner, spender, value);
}
/**
* @dev Internal function that burns an amount of the token of a given
* account, deducting from the sender's allowance for said account. Uses the
* internal burn function.
* Emits an Approval event (reflecting the reduced allowance).
* @param account The account whose tokens will be burnt.
* @param value The amount that will be burnt.
*/
function _burnFrom(address account, uint256 value) internal {
_burn(account, value);
_approve(account, msg.sender, _allowed[account][msg.sender].sub(value));
}
}
pragma solidity ^0.7.4;
// "SPDX-License-Identifier: Apache License 2.0"
import "./ERC20.sol";
/**
* @title Burnable Token
* @dev Token that can be irreversibly burned (destroyed).
*/
contract ERC20Burnable is ERC20 {
/**
* @dev Burns a specific amount of tokens.
* @param value The amount of token to be burned.
*/
function burn(uint256 value) public {
_burn(msg.sender, value);
}
/**
* @dev Burns a specific amount of tokens from the target address and decrements allowance
* @param from address The address which you want to send tokens from
* @param value uint256 The amount of token to be burned
*/
function burnFrom(address from, uint256 value) public {
_burnFrom(from, value);
}
}
pragma solidity ^0.7.4;
// "SPDX-License-Identifier: Apache License 2.0"
import "./IERC20.sol";
/**
* @title ERC20Detailed token
* @dev The decimals are only for visualization purposes.
* All the operations are done using the smallest and indivisible token unit,
* just as on Ethereum all the operations are done in wei.
*/
abstract contract ERC20Detailed is IERC20 {
string private _name;
string private _symbol;
uint8 private _decimals;
constructor (
string memory name_,
string memory symbol_,
uint8 decimals_) {
_name = name_;
_symbol = symbol_;
_decimals = decimals_;
}
/**
* @return the name of the token.
*/
function name() public view returns (string memory) {
return _name;
}
/**
* @return the symbol of the token.
*/
function symbol() public view returns (string memory) {
return _symbol;
}
/**
* @return the number of decimals of the token.
*/
function decimals() public view returns (uint8) {
return _decimals;
}
}
pragma solidity ^0.7.4;
// "SPDX-License-Identifier: MIT"
interface IERC20 {
function totalSupply() external view returns (uint256);
function balanceOf(address account) external view returns (uint256);
function allowance(address owner, address spender) external view returns (uint256);
function transfer(address recipient, uint256 amount) external returns (bool);
function approve(address spender, uint256 amount) external returns (bool);
function transferFrom(address sender, address recipient, uint256 amount) external returns (bool);
event Transfer(address indexed from, address indexed to, uint256 value);
event Approval(address indexed owner, address indexed spender, uint256 value);
}
pragma solidity ^0.7.4;
// "SPDX-License-Identifier: Apache License 2.0"
import "./ERC20Detailed.sol";
import "./ERC20Burnable.sol";
import "./Ownable.sol";
contract MasterToken is ERC20Burnable, ERC20Detailed, Ownable {
bytes32 public _sidechainAssetId;
/**
* @dev Constructor that gives the specified address all of existing tokens.
*/
constructor(
string memory name,
string memory symbol,
uint8 decimals,
address beneficiary,
uint256 supply,
bytes32 sidechainAssetId)
ERC20Detailed(name, symbol, decimals) {
_sidechainAssetId = sidechainAssetId;
_mint(beneficiary, supply);
}
fallback() external {
revert();
}
function mintTokens(address beneficiary, uint256 amount) public onlyOwner {
_mint(beneficiary, amount);
}
}
pragma solidity ^0.7.4;
// "SPDX-License-Identifier: Apache License 2.0"
/**
* @title Ownable
* @dev The Ownable contract has an owner address, and provides basic authorization control
* functions, this simplifies the implementation of "user permissions".
*/
abstract contract Ownable {
address private _owner;
event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);
/**
* @dev The Ownable constructor sets the original `owner` of the contract to the sender
* account.
*/
constructor () {
_owner = msg.sender;
emit OwnershipTransferred(address(0), _owner);
}
/**
* @return the address of the owner.
*/
function owner() public view returns (address) {
return _owner;
}
/**
* @dev Throws if called by any account other than the owner.
*/
modifier onlyOwner() {
require(isOwner());
_;
}
/**
* @return true if `msg.sender` is the owner of the contract.
*/
function isOwner() public view returns (bool) {
return msg.sender == _owner;
}
/**
* @dev Allows the current owner to relinquish control of the contract.
* @notice Renouncing to ownership will leave the contract without an owner.
* It will not be possible to call the functions with the `onlyOwner`
* modifier anymore.
*/
function renounceOwnership() public onlyOwner {
emit OwnershipTransferred(_owner, address(0));
_owner = address(0);
}
/**
* @dev 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) public onlyOwner {
_transferOwnership(newOwner);
}
/**
* @dev Transfers control of the contract to a newOwner.
* @param newOwner The address to transfer ownership to.
*/
function _transferOwnership(address newOwner) internal {
require(newOwner != address(0));
emit OwnershipTransferred(_owner, newOwner);
_owner = newOwner;
}
}
pragma solidity ^0.7.4;
// "SPDX-License-Identifier: Apache License 2.0"
/**
* @dev Wrappers over Solidity's arithmetic operations with added overflow
* checks.
*
* Arithmetic operations in Solidity wrap on overflow. This can easily result
* in bugs, because programmers usually assume that an overflow raises an
* error, which is the standard behavior in high level programming languages.
* `SafeMath` restores this intuition by reverting the transaction when an
* operation overflows.
*
* Using this library instead of the unchecked operations eliminates an entire
* class of bugs, so it's recommended to use it always.
*/
library SafeMath {
/**
* @dev Returns the addition of two unsigned integers, reverting on
* overflow.
*
* Counterpart to Solidity's `+` operator.
*
* Requirements:
* - Addition cannot overflow.
*/
function add(uint256 a, uint256 b) internal pure returns (uint256) {
uint256 c = a + b;
require(c >= a, "SafeMath: addition overflow");
return c;
}
/**
* @dev Returns the subtraction of two unsigned integers, reverting on
* overflow (when the result is negative).
*
* Counterpart to Solidity's `-` operator.
*
* Requirements:
* - Subtraction cannot overflow.
*/
function sub(uint256 a, uint256 b) internal pure returns (uint256) {
return sub(a, b, "SafeMath: subtraction overflow");
}
/**
* @dev Returns the subtraction of two unsigned integers, reverting with custom message on
* overflow (when the result is negative).
*
* Counterpart to Solidity's `-` operator.
*
* Requirements:
* - Subtraction cannot overflow.
*/
function sub(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
require(b <= a, errorMessage);
uint256 c = a - b;
return c;
}
/**
* @dev Returns the multiplication of two unsigned integers, reverting on
* overflow.
*
* Counterpart to Solidity's `*` operator.
*
* Requirements:
* - Multiplication cannot overflow.
*/
function mul(uint256 a, uint256 b) internal pure returns (uint256) {
// Gas optimization: this is cheaper than requiring 'a' not being zero, but the
// benefit is lost if 'b' is also tested.
// See: https://github.com/OpenZeppelin/openzeppelin-contracts/pull/522
if (a == 0) {
return 0;
}
uint256 c = a * b;
require(c / a == b, "SafeMath: multiplication overflow");
return c;
}
/**
* @dev Returns the integer division of two unsigned integers. Reverts on
* division by zero. The result is rounded towards zero.
*
* Counterpart to Solidity's `/` operator. Note: this function uses a
* `revert` opcode (which leaves remaining gas untouched) while Solidity
* uses an invalid opcode to revert (consuming all remaining gas).
*
* Requirements:
* - The divisor cannot be zero.
*/
function div(uint256 a, uint256 b) internal pure returns (uint256) {
return div(a, b, "SafeMath: division by zero");
}
/**
* @dev Returns the integer division of two unsigned integers. Reverts with custom message on
* division by zero. The result is rounded towards zero.
*
* Counterpart to Solidity's `/` operator. Note: this function uses a
* `revert` opcode (which leaves remaining gas untouched) while Solidity
* uses an invalid opcode to revert (consuming all remaining gas).
*
* Requirements:
* - The divisor cannot be zero.
*/
function div(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
// Solidity only automatically asserts when dividing by 0
require(b > 0, errorMessage);
uint256 c = a / b;
// assert(a == b * c + a % b); // There is no case in which this doesn't hold
return c;
}
/**
* @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
* Reverts when dividing by zero.
*
* Counterpart to Solidity's `%` operator. This function uses a `revert`
* opcode (which leaves remaining gas untouched) while Solidity uses an
* invalid opcode to revert (consuming all remaining gas).
*
* Requirements:
* - The divisor cannot be zero.
*/
function mod(uint256 a, uint256 b) internal pure returns (uint256) {
return mod(a, b, "SafeMath: modulo by zero");
}
/**
* @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
* Reverts with custom message when dividing by zero.
*
* Counterpart to Solidity's `%` operator. This function uses a `revert`
* opcode (which leaves remaining gas untouched) while Solidity uses an
* invalid opcode to revert (consuming all remaining gas).
*
* Requirements:
* - The divisor cannot be zero.
*/
function mod(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
require(b != 0, errorMessage);
return a % b;
}
}