Contract Name:
DirtyFinance
Contract Source Code:
/*////////////////////////////////////////////////////////////////////////////////////////////////////////////
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*////////////////////////////////////////////////////////////////////////////////////////////////////////////
// SPDX-License-Identifier: MIT
pragma solidity 0.7.4;
import "@openzeppelin/contracts/GSN/Context.sol";
import "@openzeppelin/contracts/token/ERC20/IERC20.sol";
import "@openzeppelin/contracts/math/SafeMath.sol";
import "@openzeppelin/contracts/utils/Address.sol";
import "@openzeppelin/contracts/access/Ownable.sol";
contract DirtyFinance is Context, IERC20, Ownable {
using SafeMath for uint256;
using Address for address;
string private constant NAME = "dirty.finance";
string private constant SYMBOL = "DIRTY";
uint8 private constant DECIMALS = 18;
mapping(address => uint256) private rewards;
mapping(address => uint256) private actual;
mapping(address => mapping(address => uint256)) private allowances;
mapping(address => bool) private excludedFromFees;
mapping(address => bool) private excludedFromRewards;
address[] private rewardExcluded;
uint256 private constant MAX = ~uint256(0);
uint256 private constant ACTUAL_TOTAL = 1000000 * 10**6 * 10**18; //1 Trillion
uint256 private rewardsTotal = (MAX - (MAX % ACTUAL_TOTAL));
uint256 private holderFeeTotal;
uint256 private regenFeeTotal;
uint256 private burnFeeTotal;
//dev reward wallets
//1% admin, 2% holders and 2% burn
uint256 public taxPercentage = 5;
uint256 public holderTaxAlloc = 20;
uint256 public regenTaxAlloc = 10;
uint256 public burnTaxAlloc = 20;
uint256 public totalTaxAlloc = regenTaxAlloc.add(holderTaxAlloc).add(burnTaxAlloc);
address public regenAddress;
address public burnAddress;
constructor(address _regenAddress) {
rewards[_regenAddress] = rewardsTotal;
emit Transfer(address(0), _regenAddress, ACTUAL_TOTAL);
regenAddress = _regenAddress;
excludeFromRewards(_msgSender());
excludeFromFees(_regenAddress);
if (_regenAddress != _msgSender()) {
excludeFromRewards(_regenAddress);
excludeFromFees(_msgSender());
}
excludeFromFees(address(0x000000000000000000000000000000000000dEaD));
}
function name() external pure returns (string memory) {
return NAME;
}
function symbol() external pure returns (string memory) {
return SYMBOL;
}
function decimals() external pure returns (uint8) {
return DECIMALS;
}
function totalSupply() external pure override returns (uint256) {
return ACTUAL_TOTAL;
}
function balanceOf(address _account) public view override returns (uint256) {
if (excludedFromRewards[_account]) {
return actual[_account];
}
return tokenWithRewards(rewards[_account]);
}
function transfer(address _recipient, uint256 _amount) public override returns (bool) {
_transfer(_msgSender(), _recipient, _amount);
return true;
}
function allowance(address _owner, address _spender) public view override returns (uint256) {
return allowances[_owner][_spender];
}
function approve(address _spender, uint256 _amount) public override returns (bool) {
_approve(_msgSender(), _spender, _amount);
return true;
}
function transferFrom(
address _sender,
address _recipient,
uint256 _amount
) public override returns (bool) {
_transfer(_sender, _recipient, _amount);
_approve(
_sender,
_msgSender(),
allowances[_sender][_msgSender()].sub(_amount, "ERC20: transfer amount exceeds allowance")
);
return true;
}
function increaseAllowance(address _spender, uint256 _addedValue) public virtual returns (bool) {
_approve(_msgSender(), _spender, allowances[_msgSender()][_spender].add(_addedValue));
return true;
}
function decreaseAllowance(address _spender, uint256 _subtractedValue) public virtual returns (bool) {
_approve(
_msgSender(),
_spender,
allowances[_msgSender()][_spender].sub(_subtractedValue, "ERC20: decreased allowance below zero")
);
return true;
}
function isExcludedFromRewards(address _account) external view returns (bool) {
return excludedFromRewards[_account];
}
function isExcludedFromFees(address _account) external view returns (bool) {
return excludedFromFees[_account];
}
function totalFees() external view returns (uint256) {
return holderFeeTotal.add(regenFeeTotal).add(burnFeeTotal);
}
function totalHolderFees() external view returns (uint256) {
return holderFeeTotal;
}
function totalRegenFees() external view returns (uint256) {
return regenFeeTotal;
}
function totalBurnFees() external view returns (uint256) {
return burnFeeTotal;
}
function distribute(uint256 _actualAmount) public {
address sender = _msgSender();
require(!excludedFromRewards[sender], "Excluded addresses cannot call this function");
(uint256 rewardAmount, , , , ) = _getValues(_actualAmount);
rewards[sender] = rewards[sender].sub(rewardAmount);
rewardsTotal = rewardsTotal.sub(rewardAmount);
holderFeeTotal = holderFeeTotal.add(_actualAmount);
}
function excludeFromFees(address _account) public onlyOwner() {
require(!excludedFromFees[_account], "Account is already excluded from fee");
excludedFromFees[_account] = true;
}
function includeInFees(address _account) public onlyOwner() {
require(excludedFromFees[_account], "Account is already included in fee");
excludedFromFees[_account] = false;
}
function excludeFromRewards(address _account) public onlyOwner() {
require(!excludedFromRewards[_account], "Account is already excluded from reward");
if (rewards[_account] > 0) {
actual[_account] = tokenWithRewards(rewards[_account]);
}
excludedFromRewards[_account] = true;
rewardExcluded.push(_account);
}
function includeInRewards(address _account) public onlyOwner() {
require(excludedFromRewards[_account], "Account is already included in rewards");
for (uint256 i = 0; i < rewardExcluded.length; i++) {
if (rewardExcluded[i] == _account) {
rewardExcluded[i] = rewardExcluded[rewardExcluded.length - 1];
actual[_account] = 0;
excludedFromRewards[_account] = false;
rewardExcluded.pop();
break;
}
}
}
function _approve(
address _owner,
address _spender,
uint256 _amount
) private {
require(_owner != address(0), "ERC20: approve from the zero address");
require(_spender != address(0), "ERC20: approve to the zero address");
allowances[_owner][_spender] = _amount;
emit Approval(_owner, _spender, _amount);
}
function _transfer(
address _sender,
address _recipient,
uint256 _amount
) private {
require(_sender != address(0), "ERC20: transfer from the zero address");
require(_recipient != address(0), "ERC20: transfer to the zero address");
require(_amount > 0, "Transfer amount must be greater than zero");
uint256 currentTaxPercentage = taxPercentage;
if (excludedFromFees[_sender] || excludedFromFees[_recipient]) {
taxPercentage = 0;
} else {
uint256 fee = _getFee(_amount);
uint256 regenFee = _getRegenFee(fee);
uint256 burnFee = _getBurnFee(fee);
_updateRegenFee(regenFee);
_updateBurnFee(burnFee);
}
if (excludedFromRewards[_sender] && !excludedFromRewards[_recipient]) {
_transferWithoutSenderRewards(_sender, _recipient, _amount);
} else if (!excludedFromRewards[_sender] && excludedFromRewards[_recipient]) {
_transferWithRecipientRewards(_sender, _recipient, _amount);
} else if (!excludedFromRewards[_sender] && !excludedFromRewards[_recipient]) {
_transferWithRewards(_sender, _recipient, _amount);
} else if (excludedFromRewards[_sender] && excludedFromRewards[_recipient]) {
_transferWithoutRewards(_sender, _recipient, _amount);
} else {
_transferWithRewards(_sender, _recipient, _amount);
}
if (currentTaxPercentage != taxPercentage) {
taxPercentage = currentTaxPercentage;
}
}
function _transferWithRewards(
address _sender,
address _recipient,
uint256 _actualAmount
) private {
(
uint256 rewardAmount,
uint256 rewardTransferAmount,
uint256 rewardFee,
uint256 actualTransferAmount,
uint256 actualFee
) = _getValues(_actualAmount);
rewards[_sender] = rewards[_sender].sub(rewardAmount);
rewards[_recipient] = rewards[_recipient].add(rewardTransferAmount);
_updateHolderFee(rewardFee, actualFee);
emit Transfer(_sender, _recipient, actualTransferAmount);
}
function _transferWithRecipientRewards(
address _sender,
address _recipient,
uint256 _actualAmount
) private {
(
uint256 rewardAmount,
uint256 rewardTransferAmount,
uint256 rewardFee,
uint256 actualTransferAmount,
uint256 actualFee
) = _getValues(_actualAmount);
rewards[_sender] = rewards[_sender].sub(rewardAmount);
actual[_recipient] = actual[_recipient].add(actualTransferAmount);
rewards[_recipient] = rewards[_recipient].add(rewardTransferAmount);
_updateHolderFee(rewardFee, actualFee);
emit Transfer(_sender, _recipient, actualTransferAmount);
}
function _transferWithoutSenderRewards(
address _sender,
address _recipient,
uint256 _actualAmount
) private {
(
uint256 rewardAmount,
uint256 rewardTransferAmount,
uint256 rewardFee,
uint256 actualTransferAmount,
uint256 actualFee
) = _getValues(_actualAmount);
actual[_sender] = actual[_sender].sub(_actualAmount);
rewards[_sender] = rewards[_sender].sub(rewardAmount);
rewards[_recipient] = rewards[_recipient].add(rewardTransferAmount);
_updateHolderFee(rewardFee, actualFee);
emit Transfer(_sender, _recipient, actualTransferAmount);
}
function _transferWithoutRewards(
address _sender,
address _recipient,
uint256 _actualAmount
) private {
(
uint256 rewardAmount,
uint256 rewardTransferAmount,
uint256 rewardFee,
uint256 actualTransferAmount,
uint256 actualFee
) = _getValues(_actualAmount);
actual[_sender] = actual[_sender].sub(_actualAmount);
rewards[_sender] = rewards[_sender].sub(rewardAmount);
actual[_recipient] = actual[_recipient].add(actualTransferAmount);
rewards[_recipient] = rewards[_recipient].add(rewardTransferAmount);
_updateHolderFee(rewardFee, actualFee);
emit Transfer(_sender, _recipient, actualTransferAmount);
}
function _updateHolderFee(uint256 _rewardFee, uint256 _actualFee) private {
rewardsTotal = rewardsTotal.sub(_rewardFee);
holderFeeTotal = holderFeeTotal.add(_actualFee);
}
function _updateRegenFee(uint256 _regenFee) private {
if (regenAddress == address(0)) {
return;
}
uint256 rewardsRate = _getRewardsRate();
uint256 rewardRegenFee = _regenFee.mul(rewardsRate);
regenFeeTotal = regenFeeTotal.add(_regenFee);
rewards[regenAddress] = rewards[regenAddress].add(rewardRegenFee);
if (excludedFromRewards[regenAddress]) {
actual[regenAddress] = actual[regenAddress].add(_regenFee);
}
}
function _updateBurnFee(uint256 _burnFee) private {
if (burnAddress == address(0)) {
return;
}
uint256 rewardsRate = _getRewardsRate();
uint256 rewardBurnFee = _burnFee.mul(rewardsRate);
burnFeeTotal = burnFeeTotal.add(_burnFee);
rewards[burnAddress] = rewards[burnAddress].add(rewardBurnFee);
if (excludedFromRewards[burnAddress]) {
actual[burnAddress] = actual[burnAddress].add(_burnFee);
}
}
function rewardsFromToken(uint256 _actualAmount, bool _deductTransferFee) public view returns (uint256) {
require(_actualAmount <= ACTUAL_TOTAL, "Amount must be less than supply");
if (!_deductTransferFee) {
(uint256 rewardAmount, , , , ) = _getValues(_actualAmount);
return rewardAmount;
} else {
(, uint256 rewardTransferAmount, , , ) = _getValues(_actualAmount);
return rewardTransferAmount;
}
}
function tokenWithRewards(uint256 _rewardAmount) public view returns (uint256) {
require(_rewardAmount <= rewardsTotal, "Amount must be less than total rewards");
uint256 rewardsRate = _getRewardsRate();
return _rewardAmount.div(rewardsRate);
}
function _getValues(uint256 _actualAmount)
private
view
returns (
uint256,
uint256,
uint256,
uint256,
uint256
)
{
(uint256 actualTransferAmount, uint256 actualFee) = _getActualValues(_actualAmount);
uint256 rewardsRate = _getRewardsRate();
(
uint256 rewardAmount,
uint256 rewardTransferAmount,
uint256 rewardFee
) = _getRewardValues(_actualAmount, actualFee, rewardsRate);
return (rewardAmount, rewardTransferAmount, rewardFee, actualTransferAmount, actualFee);
}
function _getActualValues(uint256 _actualAmount) private view returns (uint256, uint256) {
uint256 actualFee = _getFee(_actualAmount);
uint256 actualHolderFee = _getHolderFee(actualFee);
uint256 actualTransferAmount = _actualAmount.sub(actualFee);
return (actualTransferAmount, actualHolderFee);
}
function _getRewardValues(
uint256 _actualAmount,
uint256 _actualHolderFee,
uint256 _rewardsRate
)
private
view
returns (
uint256,
uint256,
uint256
)
{
uint256 actualFee = _getFee(_actualAmount).mul(_rewardsRate);
uint256 rewardAmount = _actualAmount.mul(_rewardsRate);
uint256 rewardTransferAmount = rewardAmount.sub(actualFee);
uint256 rewardFee = _actualHolderFee.mul(_rewardsRate);
return (rewardAmount, rewardTransferAmount, rewardFee);
}
function _getRewardsRate() private view returns (uint256) {
(uint256 rewardsSupply, uint256 actualSupply) = _getCurrentSupply();
return rewardsSupply.div(actualSupply);
}
function _getCurrentSupply() private view returns (uint256, uint256) {
uint256 rewardsSupply = rewardsTotal;
uint256 actualSupply = ACTUAL_TOTAL;
for (uint256 i = 0; i < rewardExcluded.length; i++) {
if (rewards[rewardExcluded[i]] > rewardsSupply || actual[rewardExcluded[i]] > actualSupply) {
return (rewardsTotal, ACTUAL_TOTAL);
}
rewardsSupply = rewardsSupply.sub(rewards[rewardExcluded[i]]);
actualSupply = actualSupply.sub(actual[rewardExcluded[i]]);
}
if (rewardsSupply < rewardsTotal.div(ACTUAL_TOTAL)) {
return (rewardsTotal, ACTUAL_TOTAL);
}
return (rewardsSupply, actualSupply);
}
function _getFee(uint256 _amount) private view returns (uint256) {
return _amount.mul(taxPercentage).div(100);
}
function _getHolderFee(uint256 _tax) private view returns (uint256) {
return _tax.mul(holderTaxAlloc).div(totalTaxAlloc);
}
function _getRegenFee(uint256 _tax) private view returns (uint256) {
return _tax.mul(regenTaxAlloc).div(totalTaxAlloc);
}
function _getBurnFee(uint256 _tax) private view returns (uint256) {
return _tax.mul(burnTaxAlloc).div(totalTaxAlloc);
}
function setTaxPercentage(uint256 _taxPercentage) external onlyOwner {
require(_taxPercentage >= 1 && _taxPercentage <= 10, "Value is outside of range 1-10");
taxPercentage = _taxPercentage;
}
function setTaxAllocations(
uint256 _holderTaxAlloc,
uint256 _regenTaxAlloc,
uint256 _burnTaxAlloc
) external onlyOwner {
totalTaxAlloc = _holderTaxAlloc.add(_regenTaxAlloc).add(_burnTaxAlloc);
require(_holderTaxAlloc >= 5 && _holderTaxAlloc <= 20, "_holderTaxAlloc is outside of range 5-20");
require(_burnTaxAlloc >= 5 && _burnTaxAlloc <= 20, "_burnTaxAlloc is outside of range 5-20");
require(_regenTaxAlloc <= 10, "_regenTaxAlloc is greater than 10");
holderTaxAlloc = _holderTaxAlloc;
regenTaxAlloc = _regenTaxAlloc;
burnTaxAlloc = _burnTaxAlloc;
}
function setRegenAddress(address _regenAddress) external onlyOwner {
regenAddress = _regenAddress;
}
function setBurnAddress(address _burnAddress) external onlyOwner {
burnAddress = _burnAddress;
}
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.7.0;
/*
* @dev Provides information about the current execution context, including the
* sender of the transaction and its data. While these are generally available
* via msg.sender and msg.data, they should not be accessed in such a direct
* manner, since when dealing with GSN meta-transactions the account sending and
* paying for execution may not be the actual sender (as far as an application
* is concerned).
*
* This contract is only required for intermediate, library-like contracts.
*/
abstract contract Context {
function _msgSender() internal view virtual returns (address payable) {
return msg.sender;
}
function _msgData() internal view virtual returns (bytes memory) {
this; // silence state mutability warning without generating bytecode - see https://github.com/ethereum/solidity/issues/2691
return msg.data;
}
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.7.0;
import "../GSN/Context.sol";
/**
* @dev Contract module which provides a basic access control mechanism, where
* there is an account (an owner) that can be granted exclusive access to
* specific functions.
*
* By default, the owner account will be the one that deploys the contract. This
* can later be changed with {transferOwnership}.
*
* This module is used through inheritance. It will make available the modifier
* `onlyOwner`, which can be applied to your functions to restrict their use to
* the owner.
*/
contract Ownable is Context {
address private _owner;
event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);
/**
* @dev Initializes the contract setting the deployer as the initial owner.
*/
constructor () {
address msgSender = _msgSender();
_owner = msgSender;
emit OwnershipTransferred(address(0), msgSender);
}
/**
* @dev Returns the address of the current owner.
*/
function owner() public view returns (address) {
return _owner;
}
/**
* @dev Throws if called by any account other than the owner.
*/
modifier onlyOwner() {
require(_owner == _msgSender(), "Ownable: caller is not the owner");
_;
}
/**
* @dev Leaves the contract without owner. It will not be possible to call
* `onlyOwner` functions anymore. Can only be called by the current owner.
*
* NOTE: Renouncing ownership will leave the contract without an owner,
* thereby removing any functionality that is only available to the owner.
*/
function renounceOwnership() public virtual onlyOwner {
emit OwnershipTransferred(_owner, address(0));
_owner = address(0);
}
/**
* @dev Transfers ownership of the contract to a new account (`newOwner`).
* Can only be called by the current owner.
*/
function transferOwnership(address newOwner) public virtual onlyOwner {
require(newOwner != address(0), "Ownable: new owner is the zero address");
emit OwnershipTransferred(_owner, newOwner);
_owner = newOwner;
}
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.7.0;
/**
* @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) {
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;
}
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.7.0;
/**
* @dev Interface of the ERC20 standard as defined in the EIP.
*/
interface IERC20 {
/**
* @dev Returns the amount of tokens in existence.
*/
function totalSupply() external view returns (uint256);
/**
* @dev Returns the amount of tokens owned by `account`.
*/
function balanceOf(address account) external view returns (uint256);
/**
* @dev Moves `amount` tokens from the caller's account to `recipient`.
*
* Returns a boolean value indicating whether the operation succeeded.
*
* Emits a {Transfer} event.
*/
function transfer(address recipient, uint256 amount) external returns (bool);
/**
* @dev Returns the remaining number of tokens that `spender` will be
* allowed to spend on behalf of `owner` through {transferFrom}. This is
* zero by default.
*
* This value changes when {approve} or {transferFrom} are called.
*/
function allowance(address owner, address spender) external view returns (uint256);
/**
* @dev Sets `amount` as the allowance of `spender` over the caller's tokens.
*
* Returns a boolean value indicating whether the operation succeeded.
*
* IMPORTANT: 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
*
* Emits an {Approval} event.
*/
function approve(address spender, uint256 amount) external returns (bool);
/**
* @dev Moves `amount` tokens from `sender` to `recipient` using the
* allowance mechanism. `amount` is then deducted from the caller's
* allowance.
*
* Returns a boolean value indicating whether the operation succeeded.
*
* Emits a {Transfer} event.
*/
function transferFrom(address sender, address recipient, uint256 amount) external returns (bool);
/**
* @dev Emitted when `value` tokens are moved from one account (`from`) to
* another (`to`).
*
* Note that `value` may be zero.
*/
event Transfer(address indexed from, address indexed to, uint256 value);
/**
* @dev Emitted when the allowance of a `spender` for an `owner` is set by
* a call to {approve}. `value` is the new allowance.
*/
event Approval(address indexed owner, address indexed spender, uint256 value);
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.7.0;
/**
* @dev Collection of functions related to the address type
*/
library Address {
/**
* @dev Returns true if `account` is a contract.
*
* [IMPORTANT]
* ====
* It is unsafe to assume that an address for which this function returns
* false is an externally-owned account (EOA) and not a contract.
*
* Among others, `isContract` will return false for the following
* types of addresses:
*
* - an externally-owned account
* - a contract in construction
* - an address where a contract will be created
* - an address where a contract lived, but was destroyed
* ====
*/
function isContract(address account) internal view returns (bool) {
// According to EIP-1052, 0x0 is the value returned for not-yet created accounts
// and 0xc5d2460186f7233c927e7db2dcc703c0e500b653ca82273b7bfad8045d85a470 is returned
// for accounts without code, i.e. `keccak256('')`
bytes32 codehash;
bytes32 accountHash = 0xc5d2460186f7233c927e7db2dcc703c0e500b653ca82273b7bfad8045d85a470;
// solhint-disable-next-line no-inline-assembly
assembly { codehash := extcodehash(account) }
return (codehash != accountHash && codehash != 0x0);
}
/**
* @dev Replacement for Solidity's `transfer`: sends `amount` wei to
* `recipient`, forwarding all available gas and reverting on errors.
*
* https://eips.ethereum.org/EIPS/eip-1884[EIP1884] increases the gas cost
* of certain opcodes, possibly making contracts go over the 2300 gas limit
* imposed by `transfer`, making them unable to receive funds via
* `transfer`. {sendValue} removes this limitation.
*
* https://diligence.consensys.net/posts/2019/09/stop-using-soliditys-transfer-now/[Learn more].
*
* IMPORTANT: because control is transferred to `recipient`, care must be
* taken to not create reentrancy vulnerabilities. Consider using
* {ReentrancyGuard} or the
* https://solidity.readthedocs.io/en/v0.5.11/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].
*/
function sendValue(address payable recipient, uint256 amount) internal {
require(address(this).balance >= amount, "Address: insufficient balance");
// solhint-disable-next-line avoid-low-level-calls, avoid-call-value
(bool success, ) = recipient.call{ value: amount }("");
require(success, "Address: unable to send value, recipient may have reverted");
}
/**
* @dev Performs a Solidity function call using a low level `call`. A
* plain`call` is an unsafe replacement for a function call: use this
* function instead.
*
* If `target` reverts with a revert reason, it is bubbled up by this
* function (like regular Solidity function calls).
*
* Returns the raw returned data. To convert to the expected return value,
* use https://solidity.readthedocs.io/en/latest/units-and-global-variables.html?highlight=abi.decode#abi-encoding-and-decoding-functions[`abi.decode`].
*
* Requirements:
*
* - `target` must be a contract.
* - calling `target` with `data` must not revert.
*
* _Available since v3.1._
*/
function functionCall(address target, bytes memory data) internal returns (bytes memory) {
return functionCall(target, data, "Address: low-level call failed");
}
/**
* @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`], but with
* `errorMessage` as a fallback revert reason when `target` reverts.
*
* _Available since v3.1._
*/
function functionCall(address target, bytes memory data, string memory errorMessage) internal returns (bytes memory) {
return _functionCallWithValue(target, data, 0, errorMessage);
}
/**
* @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
* but also transferring `value` wei to `target`.
*
* Requirements:
*
* - the calling contract must have an ETH balance of at least `value`.
* - the called Solidity function must be `payable`.
*
* _Available since v3.1._
*/
function functionCallWithValue(address target, bytes memory data, uint256 value) internal returns (bytes memory) {
return functionCallWithValue(target, data, value, "Address: low-level call with value failed");
}
/**
* @dev Same as {xref-Address-functionCallWithValue-address-bytes-uint256-}[`functionCallWithValue`], but
* with `errorMessage` as a fallback revert reason when `target` reverts.
*
* _Available since v3.1._
*/
function functionCallWithValue(address target, bytes memory data, uint256 value, string memory errorMessage) internal returns (bytes memory) {
require(address(this).balance >= value, "Address: insufficient balance for call");
return _functionCallWithValue(target, data, value, errorMessage);
}
function _functionCallWithValue(address target, bytes memory data, uint256 weiValue, string memory errorMessage) private returns (bytes memory) {
require(isContract(target), "Address: call to non-contract");
// solhint-disable-next-line avoid-low-level-calls
(bool success, bytes memory returndata) = target.call{ value: weiValue }(data);
if (success) {
return returndata;
} else {
// Look for revert reason and bubble it up if present
if (returndata.length > 0) {
// The easiest way to bubble the revert reason is using memory via assembly
// solhint-disable-next-line no-inline-assembly
assembly {
let returndata_size := mload(returndata)
revert(add(32, returndata), returndata_size)
}
} else {
revert(errorMessage);
}
}
}
}