Untitled Diff
// SPDX-License-Identifier: MIT
/**
*Submitted for verification at BscScan.com on 2021-03-28
*/
// File: src/lib/GSN/Context.sol
pragma solidity >=0.4.0;
/*
* @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.
*/
contract Context {
// Empty internal constructor, to prevent people from mistakenly deploying
// an instance of this contract, which should be used via inheritance.
constructor() internal {}
function _msgSender() internal view returns (address payable) {
return msg.sender;
}
function _msgData() internal view returns (bytes memory) {
this; // silence state mutability warning without generating bytecode - see https://github.com/ethereum/solidity/issues/2691
return msg.data;
}
}
// File: src/lib/access/Ownable.sol
pragma solidity >=0.4.0;
pragma solidity >=0.4.0;
import "../GSN/Context.sol";
/**
/**
* @dev Contract module which provides a basic access control mechanism, where
* @dev Contract module which provides a basic access control mechanism, where
* there is an account (an owner) that can be granted exclusive access to
* there is an account (an owner) that can be granted exclusive access to
* specific functions.
* specific functions.
*
*
* By default, the owner account will be the one that deploys the contract. This
* By default, the owner account will be the one that deploys the contract. This
* can later be changed with {transferOwnership}.
* can later be changed with {transferOwnership}.
*
*
* This module is used through inheritance. It will make available the modifier
* 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
* `onlyOwner`, which can be applied to your functions to restrict their use to
* the owner.
* the owner.
*/
*/
abstract contract Ownable is Context {
contract Ownable is Context {
address private _owner;
address private _owner;
event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);
event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);
/**
/**
* @dev Initializes the contract setting the deployer as the initial owner.
* @dev Initializes the contract setting the deployer as the initial owner.
*/
*/
constructor () internal {
constructor() internal {
address msgSender = _msgSender();
address msgSender = _msgSender();
_owner = msgSender;
_owner = msgSender;
emit OwnershipTransferred(address(0), msgSender);
emit OwnershipTransferred(address(0), msgSender);
}
}
/**
/**
* @dev Returns the address of the current owner.
* @dev Returns the address of the current owner.
*/
*/
function owner() public view returns (address) {
function owner() public view returns (address) {
return _owner;
return _owner;
}
}
/**
/**
* @dev Throws if called by any account other than the owner.
* @dev Throws if called by any account other than the owner.
*/
*/
modifier onlyOwner() {
modifier onlyOwner() {
require(_owner == _msgSender(), "Ownable: caller is not the owner");
require(_owner == _msgSender(), 'Ownable: caller is not the owner');
_;
_;
}
}
/**
/**
* @dev Leaves the contract without owner. It will not be possible to call
* @dev Leaves the contract without owner. It will not be possible to call
* `onlyOwner` functions anymore. Can only be called by the current owner.
* `onlyOwner` functions anymore. Can only be called by the current owner.
*
*
* NOTE: Renouncing ownership will leave the contract without an owner,
* NOTE: Renouncing ownership will leave the contract without an owner,
* thereby removing any functionality that is only available to the owner.
* thereby removing any functionality that is only available to the owner.
*/
*/
function renounceOwnership() public virtual onlyOwner {
function renounceOwnership() public onlyOwner {
emit OwnershipTransferred(_owner, address(0));
emit OwnershipTransferred(_owner, address(0));
_owner = address(0);
_owner = address(0);
}
}
/**
/**
* @dev Transfers ownership of the contract to a new account (`newOwner`).
* @dev Transfers ownership of the contract to a new account (`newOwner`).
* Can only be called by the current owner.
* Can only be called by the current owner.
*/
*/
function transferOwnership(address newOwner) public virtual onlyOwner {
function transferOwnership(address newOwner) public onlyOwner {
require(newOwner != address(0), "Ownable: new owner is the zero address");
_transferOwnership(newOwner);
}
/**
* @dev Transfers ownership of the contract to a new account (`newOwner`).
*/
function _transferOwnership(address newOwner) internal {
require(newOwner != address(0), 'Ownable: new owner is the zero address');
emit OwnershipTransferred(_owner, newOwner);
emit OwnershipTransferred(_owner, newOwner);
_owner = newOwner;
_owner = newOwner;
}
}
}
}
// File: src/lib/token/BEP20/IBEP20.sol
/*
* @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) {
pragma solidity >=0.4.0;
this; // silence state mutability warning without generating bytecode - see https://github.com/ethereum/solidity/issues/2691
return msg.data;
}
}
interface IBEP20 {
interface IBEP20 {
/**
/**
* @dev Returns the amount of tokens in existence.
* @dev Returns the amount of tokens in existence.
*/
*/
function totalSupply() external view returns (uint256);
function totalSupply() external view returns (uint256);
/**
/**
* @dev Returns the token decimals.
* @dev Returns the token decimals.
*/
*/
function decimals() external view returns (uint8);
function decimals() external view returns (uint8);
/**
/**
* @dev Returns the token symbol.
* @dev Returns the token symbol.
*/
*/
function symbol() external view returns (string memory);
function symbol() external view returns (string memory);
/**
/**
* @dev Returns the token name.
* @dev Returns the token name.
*/
*/
function name() external view returns (string memory);
function name() external view returns (string memory);
/**
/**
* @dev Returns the bep token owner.
* @dev Returns the bep token owner.
*/
*/
function getOwner() external view returns (address);
function getOwner() external view returns (address);
/**
/**
* @dev Returns the amount of tokens owned by `account`.
* @dev Returns the amount of tokens owned by `account`.
*/
*/
function balanceOf(address account) external view returns (uint256);
function balanceOf(address account) external view returns (uint256);
/**
/**
* @dev Moves `amount` tokens from the caller's account to `recipient`.
* @dev Moves `amount` tokens from the caller's account to `recipient`.
*
*
* Returns a boolean value indicating whether the operation succeeded.
* Returns a boolean value indicating whether the operation succeeded.
*
*
* Emits a {Transfer} event.
* Emits a {Transfer} event.
*/
*/
function transfer(address recipient, uint256 amount) external returns (bool);
function transfer(address recipient, uint256 amount) external returns (bool);
/**
/**
* @dev Returns the remaining number of tokens that `spender` will be
* @dev Returns the remaining number of tokens that `spender` will be
* allowed to spend on behalf of `owner` through {transferFrom}. This is
* allowed to spend on behalf of `owner` through {transferFrom}. This is
* zero by default.
* zero by default.
*
*
* This value changes when {approve} or {transferFrom} are called.
* This value changes when {approve} or {transferFrom} are called.
*/
*/
function allowance(address _owner, address spender) external view returns (uint256);
function allowance(address _owner, address spender) external view returns (uint256);
/**
/**
* @dev Sets `amount` as the allowance of `spender` over the caller's tokens.
* @dev Sets `amount` as the allowance of `spender` over the caller's tokens.
*
*
* Returns a boolean value indicating whether the operation succeeded.
* Returns a boolean value indicating whether the operation succeeded.
*
*
* IMPORTANT: Beware that changing an allowance with this method brings the risk
* 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
* that someone may use both the old and the new allowance by unfortunate
* transaction ordering. One possible solution to mitigate this race
* transaction ordering. One possible solution to mitigate this race
* condition is to first reduce the spender's allowance to 0 and set the
* condition is to first reduce the spender's allowance to 0 and set the
* desired value afterwards:
* desired value afterwards:
* https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
* https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
*
*
* Emits an {Approval} event.
* Emits an {Approval} event.
*/
*/
function approve(address spender, uint256 amount) external returns (bool);
function approve(address spender, uint256 amount) external returns (bool);
/**
/**
* @dev Moves `amount` tokens from `sender` to `recipient` using the
* @dev Moves `amount` tokens from `sender` to `recipient` using the
* allowance mechanism. `amount` is then deducted from the caller's
* allowance mechanism. `amount` is then deducted from the caller's
* allowance.
* allowance.
*
*
* Returns a boolean value indicating whether the operation succeeded.
* Returns a boolean value indicating whether the operation succeeded.
*
*
* Emits a {Transfer} event.
* Emits a {Transfer} event.
*/
*/
function transferFrom(address sender, address recipient, uint256 amount) external returns (bool);
function transferFrom(
address sender,
address recipient,
uint256 amount
) external returns (bool);
/**
/**
* @dev Emitted when `value` tokens are moved from one account (`from`) to
* @dev Emitted when `value` tokens are moved from one account (`from`) to
* another (`to`).
* another (`to`).
*
*
* Note that `value` may be zero.
* Note that `value` may be zero.
*/
*/
event Transfer(address indexed from, address indexed to, uint256 value);
event Transfer(address indexed from, address indexed to, uint256 value);
/**
/**
* @dev Emitted when the allowance of a `spender` for an `owner` is set by
* @dev Emitted when the allowance of a `spender` for an `owner` is set by
* a call to {approve}. `value` is the new allowance.
* a call to {approve}. `value` is the new allowance.
*/
*/
event Approval(address indexed owner, address indexed spender, uint256 value);
event Approval(address indexed owner, address indexed spender, uint256 value);
}
}
// File: src/lib/math/SafeMath.sol
pragma solidity >=0.4.0;
/**
/**
* @dev Wrappers over Solidity's arithmetic operations with added overflow
* @dev Wrappers over Solidity's arithmetic operations with added overflow
* checks.
* checks.
*
*
* Arithmetic operations in Solidity wrap on overflow. This can easily result
* Arithmetic operations in Solidity wrap on overflow. This can easily result
* in bugs, because programmers usually assume that an overflow raises an
* in bugs, because programmers usually assume that an overflow raises an
* error, which is the standard behavior in high level programming languages.
* error, which is the standard behavior in high level programming languages.
* `SafeMath` restores this intuition by reverting the transaction when an
* `SafeMath` restores this intuition by reverting the transaction when an
* operation overflows.
* operation overflows.
*
*
* Using this library instead of the unchecked operations eliminates an entire
* Using this library instead of the unchecked operations eliminates an entire
* class of bugs, so it's recommended to use it always.
* class of bugs, so it's recommended to use it always.
*/
*/
library SafeMath {
library SafeMath {
/**
/**
* @dev Returns the addition of two unsigned integers, reverting on
* @dev Returns the addition of two unsigned integers, reverting on
* overflow.
* overflow.
*
*
* Counterpart to Solidity's `+` operator.
* Counterpart to Solidity's `+` operator.
*
*
* Requirements:
* Requirements:
*
*
* - Addition cannot overflow.
* - Addition cannot overflow.
*/
*/
function add(uint256 a, uint256 b) internal pure returns (uint256) {
function add(uint256 a, uint256 b) internal pure returns (uint256) {
uint256 c = a + b;
uint256 c = a + b;
require(c >= a, "SafeMath: addition overflow");
require(c >= a, 'SafeMath: addition overflow');
return c;
return c;
}
}
/**
/**
* @dev Returns the subtraction of two unsigned integers, reverting on
* @dev Returns the subtraction of two unsigned integers, reverting on
* overflow (when the result is negative).
* overflow (when the result is negative).
*
*
* Counterpart to Solidity's `-` operator.
* Counterpart to Solidity's `-` operator.
*
*
* Requirements:
* Requirements:
*
*
* - Subtraction cannot overflow.
* - Subtraction cannot overflow.
*/
*/
function sub(uint256 a, uint256 b) internal pure returns (uint256) {
function sub(uint256 a, uint256 b) internal pure returns (uint256) {
return sub(a, b, "SafeMath: subtraction overflow");
return sub(a, b, 'SafeMath: subtraction overflow');
}
}
/**
/**
* @dev Returns the subtraction of two unsigned integers, reverting with custom message on
* @dev Returns the subtraction of two unsigned integers, reverting with custom message on
* overflow (when the result is negative).
* overflow (when the result is negative).
*
*
* Counterpart to Solidity's `-` operator.
* Counterpart to Solidity's `-` operator.
*
*
* Requirements:
* Requirements:
*
*
* - Subtraction cannot overflow.
* - Subtraction cannot overflow.
*/
*/
function sub(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
function sub(
uint256 a,
uint256 b,
string memory errorMessage
) internal pure returns (uint256) {
require(b <= a, errorMessage);
require(b <= a, errorMessage);
uint256 c = a - b;
uint256 c = a - b;
return c;
return c;
}
}
/**
/**
* @dev Returns the multiplication of two unsigned integers, reverting on
* @dev Returns the multiplication of two unsigned integers, reverting on
* overflow.
* overflow.
*
*
* Counterpart to Solidity's `*` operator.
* Counterpart to Solidity's `*` operator.
*
*
* Requirements:
* Requirements:
*
*
* - Multiplication cannot overflow.
* - Multiplication cannot overflow.
*/
*/
function mul(uint256 a, uint256 b) internal pure returns (uint256) {
function mul(uint256 a, uint256 b) internal pure returns (uint256) {
// Gas optimization: this is cheaper than requiring 'a' not being zero, but the
// Gas optimization: this is cheaper than requiring 'a' not being zero, but the
// benefit is lost if 'b' is also tested.
// benefit is lost if 'b' is also tested.
// See: https://github.com/OpenZeppelin/openzeppelin-contracts/pull/522
// See: https://github.com/OpenZeppelin/openzeppelin-contracts/pull/522
if (a == 0) {
if (a == 0) {
return 0;
return 0;
}
}
uint256 c = a * b;
uint256 c = a * b;
require(c / a == b, "SafeMath: multiplication overflow");
require(c / a == b, 'SafeMath: multiplication overflow');
return c;
return c;
}
}
/**
/**
* @dev Returns the integer division of two unsigned integers. Reverts on
* @dev Returns the integer division of two unsigned integers. Reverts on
* division by zero. The result is rounded towards zero.
* division by zero. The result is rounded towards zero.
*
*
* Counterpart to Solidity's `/` operator. Note: this function uses a
* Counterpart to Solidity's `/` operator. Note: this function uses a
* `revert` opcode (which leaves remaining gas untouched) while Solidity
* `revert` opcode (which leaves remaining gas untouched) while Solidity
* uses an invalid opcode to revert (consuming all remaining gas).
* uses an invalid opcode to revert (consuming all remaining gas).
*
*
* Requirements:
* Requirements:
*
*
* - The divisor cannot be zero.
* - The divisor cannot be zero.
*/
*/
function div(uint256 a, uint256 b) internal pure returns (uint256) {
function div(uint256 a, uint256 b) internal pure returns (uint256) {
return div(a, b, "SafeMath: division by zero");
return div(a, b, 'SafeMath: division by zero');
}
}
/**
/**
* @dev Returns the integer division of two unsigned integers. Reverts with custom message on
* @dev Returns the integer division of two unsigned integers. Reverts with custom message on
* division by zero. The result is rounded towards zero.
* division by zero. The result is rounded towards zero.
*
*
* Counterpart to Solidity's `/` operator. Note: this function uses a
* Counterpart to Solidity's `/` operator. Note: this function uses a
* `revert` opcode (which leaves remaining gas untouched) while Solidity
* `revert` opcode (which leaves remaining gas untouched) while Solidity
* uses an invalid opcode to revert (consuming all remaining gas).
* uses an invalid opcode to revert (consuming all remaining gas).
*
*
* Requirements:
* Requirements:
*
*
* - The divisor cannot be zero.
* - The divisor cannot be zero.
*/
*/
function div(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
function div(
uint256 a,
uint256 b,
string memory errorMessage
) internal pure returns (uint256) {
require(b > 0, errorMessage);
require(b > 0, errorMessage);
uint256 c = a / b;
uint256 c = a / b;
// assert(a == b * c + a % b); // There is no case in which this doesn't hold
// assert(a == b * c + a % b); // There is no case in which this doesn't hold
return c;
return c;
}
}
/**
/**
* @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
* @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
* Reverts when dividing by zero.
* Reverts when dividing by zero.
*
*
* Counterpart to Solidity's `%` operator. This function uses a `revert`
* Counterpart to Solidity's `%` operator. This function uses a `revert`
* opcode (which leaves remaining gas untouched) while Solidity uses an
* opcode (which leaves remaining gas untouched) while Solidity uses an
* invalid opcode to revert (consuming all remaining gas).
* invalid opcode to revert (consuming all remaining gas).
*
*
* Requirements:
* Requirements:
*
*
* - The divisor cannot be zero.
* - The divisor cannot be zero.
*/
*/
function mod(uint256 a, uint256 b) internal pure returns (uint256) {
function mod(uint256 a, uint256 b) internal pure returns (uint256) {
return mod(a, b, "SafeMath: modulo by zero");
return mod(a, b, 'SafeMath: modulo by zero');
}
}
/**
/**
* @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
* @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
* Reverts with custom message when dividing by zero.
* Reverts with custom message when dividing by zero.
*
*
* Counterpart to Solidity's `%` operator. This function uses a `revert`
* Counterpart to Solidity's `%` operator. This function uses a `revert`
* opcode (which leaves remaining gas untouched) while Solidity uses an
* opcode (which leaves remaining gas untouched) while Solidity uses an
* invalid opcode to revert (consuming all remaining gas).
* invalid opcode to revert (consuming all remaining gas).
*
*
* Requirements:
* Requirements:
*
*
* - The divisor cannot be zero.
* - The divisor cannot be zero.
*/
*/
function mod(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
function mod(
uint256 a,
uint256 b,
string memory errorMessage
) internal pure returns (uint256) {
require(b != 0, errorMessage);
require(b != 0, errorMessage);
return a % b;
return a % b;
}
}
function min(uint256 x, uint256 y) internal pure returns (uint256 z) {
z = x < y ? x : y;
}
// babylonian method (https://en.wikipedia.org/wiki/Methods_of_computing_square_roots#Babylonian_method)
function sqrt(uint256 y) internal pure returns (uint256 z) {
if (y > 3) {
z = y;
uint256 x = y / 2 + 1;
while (x < z) {
z = x;
x = (y / x + x) / 2;
}
} else if (y != 0) {
z = 1;
}
}
}
}
// File: src/lib/utils/Address.sol
pragma solidity ^0.6.2;
/**
* @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);
}
}
}
}
// File: src/lib/token/BEP20/BEP20.sol
pragma solidity >=0.4.0;
/**
/**
* @dev Implementation of the {IBEP20} interface.
* @dev Implementation of the {IBEP20} interface.
*
*
* This implementation is agnostic to the way tokens are created. This means
* This implementation is agnostic to the way tokens are created. This means
* that a supply mechanism has to be added in a derived contract using {_mint}.
* that a supply mechanism has to be added in a derived contract using {_mint}.
* For a generic mechanism see {BEP20PresetMinterPauser}.
* For a generic mechanism see {BEP20PresetMinterPauser}.
*
*
* TIP: For a detailed writeup see our guide
* TIP: For a detailed writeup see our guide
* https://forum.zeppelin.solutions/t/how-to-implement-BEP20-supply-mechanisms/226[How
* https://forum.zeppelin.solutions/t/how-to-implement-BEP20-supply-mechanisms/226[How
* to implement supply mechanisms].
* to implement supply mechanisms].
*
*
* We have followed general OpenZeppelin guidelines: functions revert instead
* We have followed general OpenZeppelin guidelines: functions revert instead
* of returning `false` on failure. This behavior is nonetheless conventional
* of returning `false` on failure. This behavior is nonetheless conventional
* and does not conflict with the expectations of BEP20 applications.
* and does not conflict with the expectations of BEP20 applications.
*
*
* Additionally, an {Approval} event is emitted on calls to {transferFrom}.
* Additionally, an {Approval} event is emitted on calls to {transferFrom}.
* This allows applications to reconstruct the allowance for all accounts just
* This allows applications to reconstruct the allowance for all accounts just
* by listening to said events. Other implementations of the EIP may not emit
* by listening to said events. Other implementations of the EIP may not emit
* these events, as it isn't required by the specification.
* these events, as it isn't required by the specification.
*
*
* Finally, the non-standard {decreaseAllowance} and {increaseAllowance}
* Finally, the non-standard {decreaseAllowance} and {increaseAllowance}
* functions have been added to mitigate the well-known issues around setting
* functions have been added to mitigate the well-known issues around setting
* allowances. See {IBEP20-approve}.
* allowances. See {IBEP20-approve}.
*/
*/
contract BEP20 is Context, IBEP20, Ownable {
contract BEP20 is Context, IBEP20, Ownable {
using SafeMath for uint256;
using SafeMath for uint256;
using Address for address;
mapping(address => uint256) private _balances;
mapping(address => uint256) internal _balances;
mapping(address => mapping(address => uint256)) private _allowances;
mapping(address => mapping(address => uint256)) internal _allowances;
uint256 private _totalSupply;
uint256 private _totalSupply;
string private _name;
string private _name;
string private _symbol;
string private _symbol;
uint8 private _decimals;
uint8 private _decimals;
/**
/**
* @dev Sets the values for {name} and {symbol}, initializes {decimals} with
* @dev Sets the values for {name} and {symbol}, initializes {decimals} with
* a default value of 18.
* a default value of 18.
*
*
* To select a different value for {decimals}, use {_setupDecimals}.
* To select a different value for {decimals}, use {_setupDecimals}.
*
*
* All three of these values are immutable: they can only be set once during
* All three of these values are immutable: they can only be set once during
* construction.
* construction.
*/
*/
constructor(string memory name, string memory symbol) public {
constructor(string memory name, string memory symbol) public {
_name = name;
_name = name;
_symbol = symbol;
_symbol = symbol;
_decimals = 18;
_decimals = 18;
}
}
/**
/**
* @dev Returns the bep token owner.
* @dev Returns the bep token owner.
*/
*/
function getOwner() external override view returns (address) {
function getOwner() external override view returns (address) {
return owner();
return owner();
}
}
/**
/**
* @dev Returns the name of the token.
* @dev Returns the token name.
*/
*/
function name() public override view returns (string memory) {
function name() public override view returns (string memory) {
return _name;
return _name;
}
}
/**
/**
* @dev Returns the symbol of the token, usually a shorter version of the
* @dev Returns the token decimals.
* name.
*/
*/
function symbol() public override view returns (string memory) {
function decimals() public override view returns (uint8) {
return _symbol;
return _decimals;
}
}
/**
/**
* @dev Returns the number of decimals used to get its user representation.
* @dev Returns the token symbol.
*/
*/
function decimals() public override view returns (uint8) {
function symbol() public override view returns (string memory) {
return _decimals;
return _symbol;
}
}
/**
/**
* @dev See {BEP20-totalSupply}.
* @dev See {BEP20-totalSupply}.
*/
*/
function totalSupply() public override view returns (uint256) {
function totalSupply() public override view returns (uint256) {
return _totalSupply;
return _totalSupply;
}
}
/**
/**
* @dev See {BEP20-balanceOf}.
* @dev See {BEP20-balanceOf}.
*/
*/
function balanceOf(address account) public override view returns (uint256) {
function balanceOf(address account) public override view returns (uint256) {
return _balances[account];
return _balances[account];
}
}
/**
/**
* @dev See {BEP20-transfer}.
* @dev See {BEP20-transfer}.
*
*
* Requirements:
* Requirements:
*
*
* - `recipient` cannot be the zero address.
* - `recipient` cannot be the zero address.
* - the caller must have a balance of at least `amount`.
* - the caller must have a balance of at least `amount`.
*/
*/
function transfer(address recipient, uint256 amount) public override returns (bool) {
function transfer(address recipient, uint256 amount) public virtual override returns (bool) {
_transfer(_msgSender(), recipient, amount);
_transfer(_msgSender(), recipient, amount);
return true;
return true;
}
}
/**
/**
* @dev See {BEP20-allowance}.
* @dev See {BEP20-allowance}.
*/
*/
function allowance(address owner, address spender) public override view returns (uint256) {
function allowance(address owner, address spender) public override view returns (uint256) {
return _allowances[owner][spender];
return _allowances[owner][spender];
}
}
/**
/**
* @dev See {BEP20-approve}.
* @dev See {BEP20-approve}.
*
*
* Requirements:
* Requirements:
*
*
* - `spender` cannot be the zero address.
* - `spender` cannot be the zero address.
*/
*/
function approve(address spender, uint256 amount) public override returns (bool) {
function approve(address spender, uint256 amount) public override returns (bool) {
_approve(_msgSender(), spender, amount);
_approve(_msgSender(), spender, amount);
return true;
return true;
}
}
/**
/**
* @dev See {BEP20-transferFrom}.
* @dev See {BEP20-transferFrom}.
*
*
* Emits an {Approval} event indicating the updated allowance. This is not
* Emits an {Approval} event indicating the updated allowance. This is not
* required by the EIP. See the note at the beginning of {BEP20};
* required by the EIP. See the note at the beginning of {BEP20};
*
*
* Requirements:
* Requirements:
* - `sender` and `recipient` cannot be the zero address.
* - `sender` and `recipient` cannot be the zero address.
* - `sender` must have a balance of at least `amount`.
* - `sender` must have a balance of at least `amount`.
* - the caller must have allowance for `sender`'s tokens of at least
* - the caller must have allowance for `sender`'s tokens of at least
* `amount`.
* `amount`.
*/
*/
function transferFrom (address sender, address recipient, uint256 amount) public override returns (bool) {
function transferFrom(
address sender,
address recipient,
uint256 amount
) public virtual override returns (bool) {
_transfer(sender, recipient, amount);
_transfer(sender, recipient, amount);
_approve(
_approve(
sender,
sender,
_msgSender(),
_msgSender(),
_allowances[sender][_msgSender()].sub(amount, 'BEP20: transfer amount exceeds allowance')
_allowances[sender][_msgSender()].sub(amount, 'BEP20: transfer amount exceeds allowance')
);
);
return true;
return true;
}
}
/**
/**
* @dev Atomically increases the allowance granted to `spender` by the caller.
* @dev Atomically increases the allowance granted to `spender` by the caller.
*
*
* This is an alternative to {approve} that can be used as a mitigation for
* This is an alternative to {approve} that can be used as a mitigation for
* problems described in {BEP20-approve}.
* problems described in {BEP20-approve}.
*
*
* Emits an {Approval} event indicating the updated allowance.
* Emits an {Approval} event indicating the updated allowance.
*
*
* Requirements:
* Requirements:
*
*
* - `spender` cannot be the zero address.
* - `spender` cannot be the zero address.
*/
*/
function increaseAllowance(address spender, uint256 addedValue) public returns (bool) {
function increaseAllowance(address spender, uint256 addedValue) public returns (bool) {
_approve(_msgSender(), spender, _allowances[_msgSender()][spender].add(addedValue));
_approve(_msgSender(), spender, _allowances[_msgSender()][spender].add(addedValue));
return true;
return true;
}
}
/**
/**
* @dev Atomically decreases the allowance granted to `spender` by the caller.
* @dev Atomically decreases the allowance granted to `spender` by the caller.
*
*
* This is an alternative to {approve} that can be used as a mitigation for
* This is an alternative to {approve} that can be used as a mitigation for
* problems described in {BEP20-approve}.
* problems described in {BEP20-approve}.
*
*
* Emits an {Approval} event indicating the updated allowance.
* Emits an {Approval} event indicating the updated allowance.
*
*
* Requirements:
* Requirements:
*
*
* - `spender` cannot be the zero address.
* - `spender` cannot be the zero address.
* - `spender` must have allowance for the caller of at least
* - `spender` must have allowance for the caller of at least
* `subtractedValue`.
* `subtractedValue`.
*/
*/
function decreaseAllowance(address spender, uint256 subtractedValue) public returns (bool) {
function decreaseAllowance(address spender, uint256 subtractedValue) public returns (bool) {
_approve(_msgSender(), spender, _allowances[_msgSender()][spender].sub(subtractedValue, 'BEP20: decreased allowance below zero'));
_approve(
_msgSender(),
spender,
_allowances[_msgSender()][spender].sub(subtractedValue, 'BEP20: decreased allowance below zero')
);
return true;
return true;
}
}
/**
/**
* @dev Creates `amount` tokens and assigns them to `msg.sender`, increasing
* @dev Creates `amount` tokens and assigns them to `msg.sender`, increasing
* the total supply.
* the total supply.
*
*
* Requirements
* Requirements
*
*
* - `msg.sender` must be the token owner
* - `msg.sender` mu
*/
function mint(uint256 amount) public onlyOwner returns (bool) {
_mint(_msgSender(), amount);
return true;
}
/**
* @dev Moves tokens `amount` from `sender` to `recipient`.
*
* This is internal function is equivalent to {transfer}, and can be used to
* e.g. implement automatic token fees, slashing mechanisms, etc.
*
* Emits a {Transfer} event.
*
* Requirements:
*
* - `sender` cannot be the zero address.
* - `recipient` cannot be the zero address.
* - `sender` must have a balance of at least `amount`.
*/
function _transfer (address sender, address recipient, uint256 amount) internal {
require(sender != address(0), 'BEP20: transfer from the zero address');
require(recipient != address(0), 'BEP20: transfer to the zero address');
_balances[sender] = _balances[sender].sub(amount, 'BEP20: transfer amount exceeds balance');
_balances[recipient] = _balances[recipient].add(amount);
emit Transfer(sender, recipient, amount);
}
/** @dev Creates `amount` tokens and assigns them to `account`, increasing
* the total supply.
*
* Emits a {Transfer} event with `from` set to the zero address.
*
* Requirements
*
* - `to` cannot be the zero address.
*/
function _mint(address account, uint256 amount) internal {
require(account != address(0), 'BEP20: mint to the zero address');
_totalSupply = _totalSupply.add(amount);
_balances[account] = _balances[account].add(amount);
emit Transfer(address(0), account, amount);
}
/**
* @dev Destroys `amount` tokens from `account`, reducing the
* total supply.
*
* Emits a {Transfer} event with `to` set to the zero address.
*
* Requirements
*
* - `account` cannot be the zero address.
* - `account` must have at least `amount` tokens.
*/
function _burn(address account, uint256 amount) internal {
require(account != address(0), 'BEP20: burn from the zero address');
_balances[account] = _balances[account].sub(amount, 'BEP20: burn amount exceeds balance');
_totalSupply = _totalSupply.sub(amount);
emit Transfer(account, address(0), amount);
}
/**
* @dev Sets `amount` as the allowance of `spender` over the `owner`s tokens.
*
* This is internal function is equivalent to `approve`, and can be used to
* e.g. set automatic allowances for certain subsystems, etc.
*
* Emits an {Approval} event.
*
* Requirements:
*
* - `owner` cannot be the zero address.
* - `spender` cannot be the zero address.
*/
function _approve (address owner, address spender, uint256 amount) internal {
require(owner != address(0), 'BEP20: approve from the zero address');
require(spender != address(0), 'BEP20: approve to the zero address');
_allowances[owner][spender] = amount;
emit Approval(owner, spender, amount);
}
/**
* @dev Destroys `amount` tokens from `account`.`amount` is then deducted
* from the caller's allowance.
*
* See {_burn} and {_approve}.
*/
function _burnFrom(address account, uint256 amount) internal {
_burn(account, amount);
_approve(account, _msgSender(), _allowances[account][_msgSender()].sub(amount, 'BEP20: burn amount exceeds allowance'));
}
}
// EggToken with Governance.
contract EggToken is BEP20('Goose Golden Egg', 'EGG') {
/// @notice Creates `_amount` token to `_to`. Must only be called by the owner (MasterChef).
function mint(address _to, uint256 _amount) public onlyOwner {
_mint(_to, _amount);
_moveDelegates(address(0), _delegates[_to], _amount);
}
// Copied and modified from YAM code:
// https://github.com/yam-finance/yam-protocol/blob/master/contracts/token/YAMGovernanceStorage.sol
// https://github.com/yam-finance/yam-protocol/blob/master/contracts/token/YAMGovernance.sol
// Which is copied and modified from COMPOUND:
// https://github.com/compound-finance/compound-protocol/blob/master/contracts/Governance/Comp.sol
/// @notice A record of each accounts delegate
mapping (address => address) internal _delegates;
/// @notice A checkpoint for marking number of votes from a given block
struct Checkpoint {
uint32 fromBlock;
uint256 votes;
}
/// @notice A record of votes checkpoints for each account, by index
mapping (address => mapping (uint32 => Checkpoint)) public checkpoints;
/// @notice The number of checkpoints for each account
mapping (address => uint32) public numCheckpoints;
/// @notice The EIP-712 typehash for the contract's domain
bytes32 public constant DOMAIN_TYPEHASH = keccak256("EIP712Domain(string name,uint256 chainId,address verifyingContract)");
/// @notice The EIP-712 typehash for the delegation struct used by the contract
bytes32 public constant DELEGATION_TYPEHASH = keccak256("Delegation(address delegatee,uint256 nonce,uint256 expiry)");
/// @notice A record of states for signing / validating signatures
mapping (address => uint) public nonces;
/// @notice An event thats emitted when an account changes its delegate
event DelegateChanged(address indexed delegator, address indexed fromDelegate, address indexed toDelegate);
/// @notice An event thats emitted when a delegate account's vote balance changes
event DelegateVotesChanged(address indexed delegate, uint previousBalance, uint newBalance);
/**
* @notice Delegate votes from `msg.sender` to `delegatee`
* @param delegator The address to get delegatee for
*/
function delegates(address delegator)
external
view
returns (address)
{
return _delegates[delegator];
}
/**
* @notice Delegate votes from `msg.sender` to `delegatee`
* @param delegatee The address to delegate votes to
*/
function delegate(address delegatee) external {
return _delegate(msg.sender, delegatee);
}
/**
* @notice Delegates votes from signatory to `delegatee`
* @param delegatee The address to delegate votes to
* @param nonce The contract state required to match the signature
* @param expiry The time at which to expire the signature
* @param v The recovery byte of the signature
* @param r Half of the ECDSA signature pair
* @param s Half of the ECDSA signature pair
*/
function delegateBySig(
address delegatee,
uint nonce,
uint expiry,
uint8 v,
bytes32 r,
bytes32 s
)
external
{
bytes32 domainSeparator = keccak256(
abi.encode(
DOMAIN_TYPEHASH,
keccak256(bytes(name())),
getChainId(),
address(this)
)
);
bytes32 structHash = keccak256(
abi.encode(
DELEGATION_TYPEHASH,
delegatee,
nonce,
expiry
)
);
bytes32 digest = keccak256(
abi.encodePacked(
"\x19\x01",
domainSeparator,
structHash
)
);
address signatory = ecrecover(digest, v, r, s);
require(signatory != address(0), "EGG::delegateBySig: invalid signature");