/**
*Submitted for verification at FtmScan.com on 2022-08-03
*/
// SPDX-License-Identifier: MIT
pragma solidity 0.6.12;
/**
* @dev Contract module that helps prevent reentrant calls to a function.
*
* Inheriting from `ReentrancyGuard` will make the {nonReentrant} modifier
* available, which can be applied to functions to make sure there are no nested
* (reentrant) calls to them.
*
* Note that because there is a single `nonReentrant` guard, functions marked as
* `nonReentrant` may not call one another. This can be worked around by making
* those functions `private`, and then adding `external` `nonReentrant` entry
* points to them.
*
* TIP: If you would like to learn more about reentrancy and alternative ways
* to protect against it, check out our blog post
* https://blog.openzeppelin.com/reentrancy-after-istanbul/[Reentrancy After Istanbul].
*/
abstract contract ReentrancyGuard {
// Booleans are more expensive than uint256 or any type that takes up a full
// word because each write operation emits an extra SLOAD to first read the
// slot's contents, replace the bits taken up by the boolean, and then write
// back. This is the compiler's defense against contract upgrades and
// pointer aliasing, and it cannot be disabled.
// The values being non-zero value makes deployment a bit more expensive,
// but in exchange the refund on every call to nonReentrant will be lower in
// amount. Since refunds are capped to a percentage of the total
// transaction's gas, it is best to keep them low in cases like this one, to
// increase the likelihood of the full refund coming into effect.
uint256 private constant _NOT_ENTERED = 1;
uint256 private constant _ENTERED = 2;
uint256 private _status;
constructor() internal {
_status = _NOT_ENTERED;
}
/**
* @dev Prevents a contract from calling itself, directly or indirectly.
* Calling a `nonReentrant` function from another `nonReentrant`
* function is not supported. It is possible to prevent this from happening
* by making the `nonReentrant` function external, and make it call a
* `private` function that does the actual work.
*/
modifier nonReentrant() {
// On the first call to nonReentrant, _notEntered will be true
require(_status != _ENTERED, "ReentrancyGuard: reentrant call");
// Any calls to nonReentrant after this point will fail
_status = _ENTERED;
_;
// By storing the original value once again, a refund is triggered (see
// https://eips.ethereum.org/EIPS/eip-2200)
_status = _NOT_ENTERED;
}
}
/*
* @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;
}
}
/**
* @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, with an overflow flag.
*
* _Available since v3.4._
*/
function tryAdd(uint256 a, uint256 b) internal pure returns (bool, uint256) {
uint256 c = a + b;
if (c < a) return (false, 0);
return (true, c);
}
/**
* @dev Returns the substraction of two unsigned integers, with an overflow flag.
*
* _Available since v3.4._
*/
function trySub(uint256 a, uint256 b) internal pure returns (bool, uint256) {
if (b > a) return (false, 0);
return (true, a - b);
}
/**
* @dev Returns the multiplication of two unsigned integers, with an overflow flag.
*
* _Available since v3.4._
*/
function tryMul(uint256 a, uint256 b) internal pure returns (bool, 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 (true, 0);
uint256 c = a * b;
if (c / a != b) return (false, 0);
return (true, c);
}
/**
* @dev Returns the division of two unsigned integers, with a division by zero flag.
*
* _Available since v3.4._
*/
function tryDiv(uint256 a, uint256 b) internal pure returns (bool, uint256) {
if (b == 0) return (false, 0);
return (true, a / b);
}
/**
* @dev Returns the remainder of dividing two unsigned integers, with a division by zero flag.
*
* _Available since v3.4._
*/
function tryMod(uint256 a, uint256 b) internal pure returns (bool, uint256) {
if (b == 0) return (false, 0);
return (true, a % b);
}
/**
* @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) {
require(b <= a, "SafeMath: subtraction overflow");
return a - b;
}
/**
* @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) {
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, reverting 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) {
require(b > 0, "SafeMath: division by zero");
return a / b;
}
/**
* @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
* reverting 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) {
require(b > 0, "SafeMath: modulo by zero");
return a % b;
}
/**
* @dev Returns the subtraction of two unsigned integers, reverting with custom message on
* overflow (when the result is negative).
*
* CAUTION: This function is deprecated because it requires allocating memory for the error
* message unnecessarily. For custom revert reasons use {trySub}.
*
* 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);
return a - b;
}
/**
* @dev Returns the integer division of two unsigned integers, reverting with custom message on
* division by zero. The result is rounded towards zero.
*
* CAUTION: This function is deprecated because it requires allocating memory for the error
* message unnecessarily. For custom revert reasons use {tryDiv}.
*
* 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);
return a / b;
}
/**
* @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
* reverting with custom message when dividing by zero.
*
* CAUTION: This function is deprecated because it requires allocating memory for the error
* message unnecessarily. For custom revert reasons use {tryMod}.
*
* 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;
}
}
/**
* @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.
*/
abstract 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() internal {
address msgSender = _msgSender();
_owner = msgSender;
emit OwnershipTransferred(address(0), msgSender);
}
/**
* @dev Returns the address of the current owner.
*/
function owner() public view virtual 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;
}
}
/**
* @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) {
// This method relies on extcodesize, which returns 0 for contracts in
// construction, since the code is only stored at the end of the
// constructor execution.
uint256 size;
// solhint-disable-next-line no-inline-assembly
assembly {
size := extcodesize(account)
}
return size > 0;
}
/**
* @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");
require(isContract(target), "Address: call to non-contract");
// solhint-disable-next-line avoid-low-level-calls
(bool success, bytes memory returndata) = target.call{ value: value }(data);
return _verifyCallResult(success, returndata, errorMessage);
}
/**
* @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
* but performing a static call.
*
* _Available since v3.3._
*/
function functionStaticCall(address target, bytes memory data) internal view returns (bytes memory) {
return functionStaticCall(target, data, "Address: low-level static call failed");
}
/**
* @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
* but performing a static call.
*
* _Available since v3.3._
*/
function functionStaticCall(
address target,
bytes memory data,
string memory errorMessage
) internal view returns (bytes memory) {
require(isContract(target), "Address: static call to non-contract");
// solhint-disable-next-line avoid-low-level-calls
(bool success, bytes memory returndata) = target.staticcall(data);
return _verifyCallResult(success, returndata, errorMessage);
}
/**
* @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
* but performing a delegate call.
*
* _Available since v3.4._
*/
function functionDelegateCall(address target, bytes memory data) internal returns (bytes memory) {
return functionDelegateCall(target, data, "Address: low-level delegate call failed");
}
/**
* @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
* but performing a delegate call.
*
* _Available since v3.4._
*/
function functionDelegateCall(
address target,
bytes memory data,
string memory errorMessage
) internal returns (bytes memory) {
require(isContract(target), "Address: delegate call to non-contract");
// solhint-disable-next-line avoid-low-level-calls
(bool success, bytes memory returndata) = target.delegatecall(data);
return _verifyCallResult(success, returndata, errorMessage);
}
function _verifyCallResult(
bool success,
bytes memory returndata,
string memory errorMessage
) private pure returns (bytes memory) {
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);
}
}
}
}
interface IERC20 {
/**
* @dev Returns the amount of tokens in existence.
*/
function totalSupply() external view returns (uint256);
/**
* @dev Returns the token decimals.
*/
function decimals() external view returns (uint8);
/**
* @dev Returns the token symbol.
*/
function symbol() external view returns (string memory);
/**
* @dev Returns the token name.
*/
function name() external view returns (string memory);
/**
* @dev Returns the bep token owner.
*/
function getOwner() external view returns (address);
/**
* @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);
}
contract ERC20 is Context, IERC20, Ownable {
using SafeMath for uint256;
using Address for address;
mapping(address => uint256) private _balances;
mapping(address => mapping(address => uint256)) private _allowances;
uint256 private _totalSupply;
string private _name;
string private _symbol;
uint8 private _decimals;
uint256 constant MAXSUPPLY = 100000 ether;
/**
* @dev Sets the values for {name} and {symbol}, initializes {decimals} with
* a default value of 18.
*
* To select a different value for {decimals}, use {_setupDecimals}.
*
* All three of these values are immutable: they can only be set once during
* construction.
*/
constructor(string memory name, string memory symbol) public {
_name = name;
_symbol = symbol;
_decimals = 18;
}
/**
* @dev Returns the bep token owner.
*/
function getOwner() external view override returns (address) {
return owner();
}
/**
* @dev Returns the token name.
*/
function name() public view override returns (string memory) {
return _name;
}
/**
* @dev Returns the token decimals.
*/
function decimals() public view override returns (uint8) {
return _decimals;
}
/**
* @dev Returns the token symbol.
*/
function symbol() public view override returns (string memory) {
return _symbol;
}
/**
* @dev See {ERC20-totalSupply}.
*/
function totalSupply() public view override returns (uint256) {
return _totalSupply;
}
function maxSupply() public pure returns (uint256) {
return MAXSUPPLY;
}
/**
* @dev See {ERC20-balanceOf}.
*/
function balanceOf(address account) public view override returns (uint256) {
return _balances[account];
}
/**
* @dev See {ERC20-transfer}.
*
* Requirements:
*
* - `recipient` cannot be the zero address.
* - the caller must have a balance of at least `amount`.
*/
function transfer(address recipient, uint256 amount) public override returns (bool) {
_transfer(_msgSender(), recipient, amount);
return true;
}
/**
* @dev See {ERC20-allowance}.
*/
function allowance(address owner, address spender) public view override returns (uint256) {
return _allowances[owner][spender];
}
/**
* @dev See {ERC20-approve}.
*
* Requirements:
*
* - `spender` cannot be the zero address.
*/
function approve(address spender, uint256 amount) public override returns (bool) {
_approve(_msgSender(), spender, amount);
return true;
}
/**
* @dev See {ERC20-transferFrom}.
*
* Emits an {Approval} event indicating the updated allowance. This is not
* required by the EIP. See the note at the beginning of {ERC20};
*
* Requirements:
* - `sender` and `recipient` cannot be the zero address.
* - `sender` must have a balance of at least `amount`.
* - the caller must have allowance for `sender`'s tokens of at least
* `amount`.
*/
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;
}
/**
* @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
* problems described in {ERC20-approve}.
*
* Emits an {Approval} event indicating the updated allowance.
*
* Requirements:
*
* - `spender` cannot be the zero address.
*/
function increaseAllowance(address spender, uint256 addedValue) public returns (bool) {
_approve(_msgSender(), spender, _allowances[_msgSender()][spender].add(addedValue));
return true;
}
/**
* @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
* problems described in {ERC20-approve}.
*
* Emits an {Approval} event indicating the updated allowance.
*
* Requirements:
*
* - `spender` cannot be the zero address.
* - `spender` must have allowance for the caller of at least
* `subtractedValue`.
*/
function decreaseAllowance(address spender, uint256 subtractedValue) public returns (bool) {
_approve(
_msgSender(),
spender,
_allowances[_msgSender()][spender].sub(subtractedValue, "ERC20: decreased allowance below zero")
);
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 virtual {
require(sender != address(0), "ERC20: transfer from the zero address");
require(recipient != address(0), "ERC20: transfer to the zero address");
_balances[sender] = _balances[sender].sub(amount, "ERC20: 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), "ERC20: mint to the zero address");
require(_totalSupply.add(amount) <= MAXSUPPLY, "Max supply reached");
_totalSupply = _totalSupply.add(amount);
_balances[account] = _balances[account].add(amount);
emit Transfer(address(0), account, 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), "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);
}
}
// Doin.
contract Doin is ERC20("StableDoin", "Doin") {
/// @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);
}
}
/**
* @title SafeERC20
* @dev Wrappers around ERC20 operations that throw on failure (when the token
* contract returns false). Tokens that return no value (and instead revert or
* throw on failure) are also supported, non-reverting calls are assumed to be
* successful.
* To use this library you can add a `using SafeERC20 for IERC20;` statement to your contract,
* which allows you to call the safe operations as `token.safeTransfer(...)`, etc.
*/
library SafeERC20 {
using SafeMath for uint256;
using Address for address;
function safeTransfer(
IERC20 token,
address to,
uint256 value
) internal {
_callOptionalReturn(token, abi.encodeWithSelector(token.transfer.selector, to, value));
}
function safeTransferFrom(
IERC20 token,
address from,
address to,
uint256 value
) internal {
_callOptionalReturn(token, abi.encodeWithSelector(token.transferFrom.selector, from, to, value));
}
/**
* @dev Deprecated. This function has issues similar to the ones found in
* {IERC20-approve}, and its usage is discouraged.
*
* Whenever possible, use {safeIncreaseAllowance} and
* {safeDecreaseAllowance} instead.
*/
function safeApprove(
IERC20 token,
address spender,
uint256 value
) internal {
// safeApprove should only be called when setting an initial allowance,
// or when resetting it to zero. To increase and decrease it, use
// 'safeIncreaseAllowance' and 'safeDecreaseAllowance'
// solhint-disable-next-line max-line-length
require(
(value == 0) || (token.allowance(address(this), spender) == 0),
"SafeERC20: approve from non-zero to non-zero allowance"
);
_callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, value));
}
function safeIncreaseAllowance(
IERC20 token,
address spender,
uint256 value
) internal {
uint256 newAllowance = token.allowance(address(this), spender).add(value);
_callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
}
function safeDecreaseAllowance(
IERC20 token,
address spender,
uint256 value
) internal {
uint256 newAllowance = token.allowance(address(this), spender).sub(
value,
"SafeERC20: decreased allowance below zero"
);
_callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
}
/**
* @dev Imitates a Solidity high-level call (i.e. a regular function call to a contract), relaxing the requirement
* on the return value: the return value is optional (but if data is returned, it must not be false).
* @param token The token targeted by the call.
* @param data The call data (encoded using abi.encode or one of its variants).
*/
function _callOptionalReturn(IERC20 token, bytes memory data) private {
// We need to perform a low level call here, to bypass Solidity's return data size checking mechanism, since
// we're implementing it ourselves. We use {Address.functionCall} to perform this call, which verifies that
// the target address contains contract code and also asserts for success in the low-level call.
bytes memory returndata = address(token).functionCall(data, "SafeERC20: low-level call failed");
if (returndata.length > 0) {
// Return data is optional
// solhint-disable-next-line max-line-length
require(abi.decode(returndata, (bool)), "SafeERC20: ERC20 operation did not succeed");
}
}
}
// MasterChef is the master of Doin. He can make Doin and he is a fair guy.
//
// Note that it's ownable and the owner wields tremendous power. The ownership
// will be transferred to a governance smart contract once Doin is sufficiently
// distributed and the community can show to govern itself.
//
// Have fun reading it. Hopefully it's bug-free. God bless.
contract DoinMasterChef is Ownable, ReentrancyGuard {
using SafeMath for uint256;
using SafeERC20 for IERC20;
// Info of each user.
struct UserInfo {
uint256 amount; // How many LP tokens the user has provided.
uint256 rewardDebt; // Reward debt. See explanation below.
//
// We do some fancy math here. Basically, any point in time, the amount of Doin
// entitled to a user but is pending to be distributed is:
//
// pending reward = (user.amount * pool.accDoinPerShare) - user.rewardDebt
//
// Whenever a user deposits or withdraws LP tokens to a pool. Here's what happens:
// 1. The pool's `accDoinPerShare` (and `lastRewardBlock`) gets updated.
// 2. User receives the pending reward sent to his/her address.
// 3. User's `amount` gets updated.
// 4. User's `rewardDebt` gets updated.
}
// Info of each pool.
struct PoolInfo {
IERC20 lpToken; // Address of LP token contract.
uint256 allocPoint; // How many allocation points assigned to this pool. ALPHAs to distribute per block.
uint256 lastRewardBlock; // Last block number that Doin distribution occurs.
uint256 accDoinPerShare; // Accumulated Doin per share, times 1e18. See below.
uint16 depositFeeBP; // Deposit fee in basis points
uint256 lpSupply;
}
// The Doin TOKEN!
Doin public immutable token;
// Dev address.
address public devaddr;
// Doin tokens created per block.
uint256 public DoinPerBlock;
// Deposit Fee address
address public feeAddress;
// Info of each pool.
PoolInfo[] public poolInfo;
// Info of each user that stakes LP tokens.
mapping(uint256 => mapping(address => UserInfo)) public userInfo;
// Total allocation points. Must be the sum of all allocation points in all pools.
uint256 public totalAllocPoint = 0;
// The block number when Doin mining starts.
uint256 public startBlock;
// Maximum DoinPerBlock
uint256 public MAX_EMISSION_RATE = 1 ether;
event Deposit(address indexed user, uint256 indexed pid, uint256 amount);
event Withdraw(address indexed user, uint256 indexed pid, uint256 amount);
event EmergencyWithdraw(address indexed user, uint256 indexed pid, uint256 amount);
event SetFeeAddress(address indexed user, address indexed newAddress);
event SetDevAddress(address indexed user, address indexed newAddress);
event UpdateEmissionRate(address indexed user, uint256 DoinPerBlock);
event addPool(uint256 indexed pid, address lpToken, uint256 allocPoint, uint256 depositFeeBP);
event setPool(uint256 indexed pid, address lpToken, uint256 allocPoint, uint256 depositFeeBP);
event UpdateStartBlock(uint256 newStartBlock);
event DoinMintError(bytes reason);
constructor(
Doin _tokenAddress,
address _devaddr,
address _feeAddress,
uint256 _DoinPerBlock,
uint256 _startBlock
) public {
token = _tokenAddress;
devaddr = _devaddr;
feeAddress = _feeAddress;
DoinPerBlock = _DoinPerBlock;
startBlock = _startBlock;
}
function poolLength() external view returns (uint256) {
return poolInfo.length;
}
mapping(IERC20 => bool) public poolExistence;
modifier nonDuplicated(IERC20 _lpToken) {
require(poolExistence[_lpToken] == false, "nonDuplicated: duplicated");
_;
}
// Add a new lp to the pool. Can only be called by the owner.
function add(
uint256 _allocPoint,
IERC20 _lpToken,
uint16 _depositFeeBP,
bool _withUpdate
) external onlyOwner nonDuplicated(_lpToken) {
// valid ERC20 token
_lpToken.balanceOf(address(this));
require(_depositFeeBP <= 100, "add: invalid deposit fee basis points");
if (_withUpdate) {
massUpdatePools();
}
uint256 lastRewardBlock = block.number > startBlock ? block.number : startBlock;
totalAllocPoint = totalAllocPoint.add(_allocPoint);
poolExistence[_lpToken] = true;
poolInfo.push(
PoolInfo({
lpToken: _lpToken,
allocPoint: _allocPoint,
lastRewardBlock: lastRewardBlock,
accDoinPerShare: 0,
depositFeeBP: _depositFeeBP,
lpSupply: 0
})
);
emit addPool(poolInfo.length - 1, address(_lpToken), _allocPoint, _depositFeeBP);
}
// Update the given pool's Doin allocation point and deposit fee. Can only be called by the owner.
function set(
uint256 _pid,
uint256 _allocPoint,
uint16 _depositFeeBP,
bool _withUpdate
) external onlyOwner {
require(_depositFeeBP <= 100, "set: invalid deposit fee basis points");
if (_withUpdate) {
massUpdatePools();
}
totalAllocPoint = totalAllocPoint.sub(poolInfo[_pid].allocPoint).add(_allocPoint);
poolInfo[_pid].allocPoint = _allocPoint;
poolInfo[_pid].depositFeeBP = _depositFeeBP;
emit setPool(_pid, address(poolInfo[_pid].lpToken), _allocPoint, _depositFeeBP);
}
// Return reward multiplier over the given _from to _to block.
function getMultiplier(uint256 _from, uint256 _to) public pure returns (uint256) {
return _to.sub(_from);
}
// View function to see pending Alphas on frontend.
function pendingDoin(uint256 _pid, address _user) external view returns (uint256) {
PoolInfo storage pool = poolInfo[_pid];
UserInfo storage user = userInfo[_pid][_user];
uint256 accDoinPerShare = pool.accDoinPerShare;
if (block.number > pool.lastRewardBlock && pool.lpSupply != 0 && totalAllocPoint > 0) {
uint256 multiplier = getMultiplier(pool.lastRewardBlock, block.number);
uint256 doinReward = multiplier.mul(DoinPerBlock).mul(pool.allocPoint).div(totalAllocPoint);
uint256 devReward = doinReward.div(10);
uint256 totalRewards = token.totalSupply().add(devReward).add(doinReward);
if (totalRewards > token.maxSupply()) {
doinReward = token.maxSupply().sub(token.totalSupply());
}
accDoinPerShare = accDoinPerShare.add(doinReward.mul(1e18).div(pool.lpSupply));
}
return user.amount.mul(accDoinPerShare).div(1e18).sub(user.rewardDebt);
}
// Update reward variables for all pools. Be careful of gas spending!
function massUpdatePools() public {
uint256 length = poolInfo.length;
for (uint256 pid = 0; pid < length; ++pid) {
updatePool(pid);
}
}
// Update reward variables of the given pool to be up-to-date.
function updatePool(uint256 _pid) public {
PoolInfo storage pool = poolInfo[_pid];
if (block.number <= pool.lastRewardBlock) {
return;
}
if (pool.lpSupply == 0 || pool.allocPoint == 0) {
pool.lastRewardBlock = block.number;
return;
}
uint256 multiplier = getMultiplier(pool.lastRewardBlock, block.number);
uint256 doinReward = multiplier.mul(DoinPerBlock).mul(pool.allocPoint).div(totalAllocPoint);
uint256 devReward = doinReward.div(10);
uint256 totalRewards = token.totalSupply().add(devReward).add(doinReward);
if (totalRewards <= token.maxSupply()) {
// mint as normal as not at maxSupply
token.mint(devaddr, doinReward.div(10));
token.mint(address(this), doinReward);
} else {
// mint the difference only to MC, update doinReward
doinReward = token.maxSupply().sub(token.totalSupply());
token.mint(address(this), doinReward);
}
if (doinReward != 0) {
// only calculate and update if doinReward is non 0
pool.accDoinPerShare = pool.accDoinPerShare.add(doinReward.mul(1e18).div(pool.lpSupply));
}
pool.lastRewardBlock = block.number;
}
// Deposit LP tokens to MasterChef for Doin allocation.
function deposit(uint256 _pid, uint256 _amount) external nonReentrant {
PoolInfo storage pool = poolInfo[_pid];
UserInfo storage user = userInfo[_pid][msg.sender];
updatePool(_pid);
if (user.amount > 0) {
uint256 pending = user.amount.mul(pool.accDoinPerShare).div(1e18).sub(user.rewardDebt);
if (pending > 0) {
safeDoinTransfer(msg.sender, pending);
}
}
if (_amount > 0) {
uint256 balanceBefore = pool.lpToken.balanceOf(address(this));
pool.lpToken.safeTransferFrom(address(msg.sender), address(this), _amount);
_amount = pool.lpToken.balanceOf(address(this)) - balanceBefore;
if (pool.depositFeeBP > 0) {
uint256 depositFee = _amount.mul(pool.depositFeeBP).div(10000);
pool.lpToken.safeTransfer(feeAddress, depositFee);
user.amount = user.amount.add(_amount).sub(depositFee);
pool.lpSupply = pool.lpSupply.add(_amount).sub(depositFee);
} else {
user.amount = user.amount.add(_amount);
pool.lpSupply = pool.lpSupply.add(_amount);
}
}
user.rewardDebt = user.amount.mul(pool.accDoinPerShare).div(1e18);
emit Deposit(msg.sender, _pid, _amount);
}
// Withdraw LP tokens from MasterChef.
function withdraw(uint256 _pid, uint256 _amount) external nonReentrant {
PoolInfo storage pool = poolInfo[_pid];
UserInfo storage user = userInfo[_pid][msg.sender];
require(user.amount >= _amount, "withdraw: not good");
updatePool(_pid);
uint256 pending = user.amount.mul(pool.accDoinPerShare).div(1e18).sub(user.rewardDebt);
if (pending > 0) {
safeDoinTransfer(msg.sender, pending);
}
if (_amount > 0) {
user.amount = user.amount.sub(_amount);
pool.lpToken.safeTransfer(address(msg.sender), _amount);
pool.lpSupply = pool.lpSupply.sub(_amount);
}
user.rewardDebt = user.amount.mul(pool.accDoinPerShare).div(1e18);
emit Withdraw(msg.sender, _pid, _amount);
}
// Withdraw without caring about rewards. EMERGENCY ONLY.
function emergencyWithdraw(uint256 _pid) external nonReentrant {
PoolInfo storage pool = poolInfo[_pid];
UserInfo storage user = userInfo[_pid][msg.sender];
uint256 amount = user.amount;
user.amount = 0;
user.rewardDebt = 0;
pool.lpToken.safeTransfer(address(msg.sender), amount);
if (pool.lpSupply >= amount) {
pool.lpSupply = pool.lpSupply.sub(amount);
} else {
pool.lpSupply = 0;
}
emit EmergencyWithdraw(msg.sender, _pid, amount);
}
// Safe Doin transfer function, just in case if rounding error causes pool to not have enough Doins.
function safeDoinTransfer(address _to, uint256 _amount) internal {
uint256 DoinBal = token.balanceOf(address(this));
bool transferSuccess = false;
if (_amount > DoinBal) {
transferSuccess = token.transfer(_to, DoinBal);
} else {
transferSuccess = token.transfer(_to, _amount);
}
require(transferSuccess, "safeDoinTransfer: transfer failed");
}
// Update dev address.
function setDevAddress(address _devaddr) external {
require(msg.sender == devaddr, "setDevAddress: ACCESS DENIED");
require(_devaddr != address(0), "setDevAddress: INCORRECT INPUT");
devaddr = _devaddr;
emit SetDevAddress(msg.sender, _devaddr);
}
function setFeeAddress(address _feeAddress) external {
require(msg.sender == feeAddress, "setFeeAddress: ACCESS DENIED");
require(_feeAddress != address(0), "setFeeAddress: INCORRECT INPUT");
feeAddress = _feeAddress;
emit SetFeeAddress(msg.sender, _feeAddress);
}
// Pancake has to add hidden dummy pools inorder to alter the emission, here we make it simple and transparent to all.
function updateEmissionRate(uint256 _DoinPerBlock) external onlyOwner {
require(_DoinPerBlock <= MAX_EMISSION_RATE, "INCORRECT INPUT");
massUpdatePools();
DoinPerBlock = _DoinPerBlock;
emit UpdateEmissionRate(msg.sender, _DoinPerBlock);
}
// Only update before start of farm
function updateStartBlock(uint256 _newStartBlock) external onlyOwner {
require(block.number < startBlock, "FARM ALREADY STARTED");
require(block.number < _newStartBlock, "INCORRECT INPUT");
uint256 length = poolInfo.length;
for (uint256 pid = 0; pid < length; ++pid) {
PoolInfo storage pool = poolInfo[pid];
pool.lastRewardBlock = _newStartBlock;
}
startBlock = _newStartBlock;
emit UpdateStartBlock(startBlock);
}
}
