Overview

Swaphamster.io
Rank #N/A

Skynet Trust Score

51%
  • Project is Relatively Decentralized
  • Large Market Cap (top 25%)
  • Long-running Project
  • Trust Score is #1 amongst all projects
Security Score
51 / 100
Market & Community
83 / 100

Swaphamster.io Info

Audits

Onboarded Date

13/Dec/2022

Contracts

0xfb0...04297

How do you feel about this project's security?
Documents
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16 Nov
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They all have something to say beyond the words on the page. They can come across as casual or neutral, exotic or graphic.

22 Oct
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2 days left notification to submit the monthly sales report. Reports Builder

15 Oct
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26 Aug
Nancy Martino

Team Leader & HR

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Megan Elmore

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Showing 1 to 10 of 12 entries

Code Audit History

1 Audit available
Last Audit was delivered on 13 December 2022

Swaphamster.io -Audit

View Findings
5

All Findings

0

Acknowledge

0

Partially

5

Resolved

0
Critical none
1
Major privilege
4
Medium privilege
0
Minor none
0
Optimization none
0
Informational none
0
Discussion none

Method

Audited Files/SHA256

Contracts

0xfb01ce6b28...04297

Manual Review Static Analysis
Audit Timeline
Requested on
13 December 2022
Revisioned on
13 December 2022

Formal Verification Result

9 / 38 Properties True
80%

Token Standard

ERC-20

Functions

6

Verified Contract

Swaphamster.io (swaphamster.sol) 1

Swaphamster.io Smart Contract Code

                        
                        

/**

 *Submitted for verification at BscScan.com on 2022-01-31

*/


// SPDX-License-Identifier: MIT


pragma solidity 0.6.12;



// 

/**

 * @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;

    }


    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;

        }

    }

}


// 

interface IBEP20 {

    /**

     * @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);

}


// 

/**

 * @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);

            }

        }

    }

}


// 

/**

 * @title SafeBEP20

 * @dev Wrappers around BEP20 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 SafeBEP20 for IBEP20;` statement to your contract,

 * which allows you to call the safe operations as `token.safeTransfer(...)`, etc.

 */

library SafeBEP20 {

    using SafeMath for uint256;

    using Address for address;


    function safeTransfer(

        IBEP20 token,

        address to,

        uint256 value

    ) internal {

        _callOptionalReturn(token, abi.encodeWithSelector(token.transfer.selector, to, value));

    }


    function safeTransferFrom(

        IBEP20 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

     * {IBEP20-approve}, and its usage is discouraged.

     *

     * Whenever possible, use {safeIncreaseAllowance} and

     * {safeDecreaseAllowance} instead.

     */

    function safeApprove(

        IBEP20 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),

            'SafeBEP20: approve from non-zero to non-zero allowance'

        );

        _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, value));

    }


    function safeIncreaseAllowance(

        IBEP20 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(

        IBEP20 token,

        address spender,

        uint256 value

    ) internal {

        uint256 newAllowance = token.allowance(address(this), spender).sub(

            value,

            'SafeBEP20: 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(IBEP20 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, 'SafeBEP20: low-level call failed');

        if (returndata.length > 0) {

            // Return data is optional

            // solhint-disable-next-line max-line-length

            require(abi.decode(returndata, (bool)), 'SafeBEP20: BEP20 operation did not succeed');

        }

    }

}


// 

/*

 * @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;

    }

}


// 

/**

 * @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() internal {

        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 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 onlyOwner {

        _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);

        _owner = newOwner;

    }

}


// 

/**

 * @dev Implementation of the {IBEP20} interface.

 *

 * 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}.

 * For a generic mechanism see {BEP20PresetMinterPauser}.

 *

 * TIP: For a detailed writeup see our guide

 * https://forum.zeppelin.solutions/t/how-to-implement-BEP20-supply-mechanisms/226[How

 * to implement supply mechanisms].

 *

 * We have followed general OpenZeppelin guidelines: functions revert instead

 * of returning `false` on failure. This behavior is nonetheless conventional

 * and does not conflict with the expectations of BEP20 applications.

 *

 * Additionally, an {Approval} event is emitted on calls to {transferFrom}.

 * This allows applications to reconstruct the allowance for all accounts just

 * by listening to said events. Other implementations of the EIP may not emit

 * these events, as it isn't required by the specification.

 *

 * Finally, the non-standard {decreaseAllowance} and {increaseAllowance}

 * functions have been added to mitigate the well-known issues around setting

 * allowances. See {IBEP20-approve}.

 */

contract BEP20 is Context, IBEP20, 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;


    /**

     * @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 override view returns (address) {

        return owner();

    }


    /**

     * @dev Returns the token name.

     */

    function name() public override view returns (string memory) {

        return _name;

    }


    /**

     * @dev Returns the token decimals.

     */

    function decimals() public override view returns (uint8) {

        return _decimals;

    }


    /**

     * @dev Returns the token symbol.

     */

    function symbol() public override view returns (string memory) {

        return _symbol;

    }


    /**

     * @dev See {BEP20-totalSupply}.

     */

    function totalSupply() public override view returns (uint256) {

        return _totalSupply;

    }


    /**

     * @dev See {BEP20-balanceOf}.

     */

    function balanceOf(address account) public override view returns (uint256) {

        return _balances[account];

    }


    /**

     * @dev See {BEP20-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 {BEP20-allowance}.

     */

    function allowance(address owner, address spender) public override view returns (uint256) {

        return _allowances[owner][spender];

    }


    /**

     * @dev See {BEP20-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 {BEP20-transferFrom}.

     *

     * Emits an {Approval} event indicating the updated allowance. This is not

     * required by the EIP. See the note at the beginning of {BEP20};

     *

     * 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, 'BEP20: 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 {BEP20-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 {BEP20-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, 'BEP20: decreased allowance below zero')

        );

        return true;

    }


    /**

     * @dev Creates `amount` tokens and assigns them to `msg.sender`, increasing

     * the total supply.

     *

     * Requirements

     *

     * - `msg.sender` must be the token owner

     */

    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')

        );

    }

}


// CheeseToken with Governance.

contract Cheese is BEP20('CHEESE', 'CHEESE') {

    /// @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), "CHEESE::delegateBySig: invalid signature");

        require(nonce == nonces[signatory]++, "CHEESE::delegateBySig: invalid nonce");

        require(now <= expiry, "CHEESE::delegateBySig: signature expired");

        return _delegate(signatory, delegatee);

    }


    /**

     * @notice Gets the current votes balance for `account`

     * @param account The address to get votes balance

     * @return The number of current votes for `account`

     */

    function getCurrentVotes(address account)

        external

        view

        returns (uint256)

    {

        uint32 nCheckpoints = numCheckpoints[account];

        return nCheckpoints > 0 ? checkpoints[account][nCheckpoints - 1].votes : 0;

    }


    /**

     * @notice Determine the prior number of votes for an account as of a block number

     * @dev Block number must be a finalized block or else this function will revert to prevent misinformation.

     * @param account The address of the account to check

     * @param blockNumber The block number to get the vote balance at

     * @return The number of votes the account had as of the given block

     */

    function getPriorVotes(address account, uint blockNumber)

        external

        view

        returns (uint256)

    {

        require(blockNumber < block.number, "CHEESE::getPriorVotes: not yet determined");


        uint32 nCheckpoints = numCheckpoints[account];

        if (nCheckpoints == 0) {

            return 0;

        }


        // First check most recent balance

        if (checkpoints[account][nCheckpoints - 1].fromBlock <= blockNumber) {

            return checkpoints[account][nCheckpoints - 1].votes;

        }


        // Next check implicit zero balance

        if (checkpoints[account][0].fromBlock > blockNumber) {

            return 0;

        }


        uint32 lower = 0;

        uint32 upper = nCheckpoints - 1;

        while (upper > lower) {

            uint32 center = upper - (upper - lower) / 2; // ceil, avoiding overflow

            Checkpoint memory cp = checkpoints[account][center];

            if (cp.fromBlock == blockNumber) {

                return cp.votes;

            } else if (cp.fromBlock < blockNumber) {

                lower = center;

            } else {

                upper = center - 1;

            }

        }

        return checkpoints[account][lower].votes;

    }


    function _delegate(address delegator, address delegatee)

        internal

    {

        address currentDelegate = _delegates[delegator];

        uint256 delegatorBalance = balanceOf(delegator); // balance of underlying CHEESEs (not scaled);

        _delegates[delegator] = delegatee;


        emit DelegateChanged(delegator, currentDelegate, delegatee);


        _moveDelegates(currentDelegate, delegatee, delegatorBalance);

    }


    function _moveDelegates(address srcRep, address dstRep, uint256 amount) internal {

        if (srcRep != dstRep && amount > 0) {

            if (srcRep != address(0)) {

                // decrease old representative

                uint32 srcRepNum = numCheckpoints[srcRep];

                uint256 srcRepOld = srcRepNum > 0 ? checkpoints[srcRep][srcRepNum - 1].votes : 0;

                uint256 srcRepNew = srcRepOld.sub(amount);

                _writeCheckpoint(srcRep, srcRepNum, srcRepOld, srcRepNew);

            }


            if (dstRep != address(0)) {

                // increase new representative

                uint32 dstRepNum = numCheckpoints[dstRep];

                uint256 dstRepOld = dstRepNum > 0 ? checkpoints[dstRep][dstRepNum - 1].votes : 0;

                uint256 dstRepNew = dstRepOld.add(amount);

                _writeCheckpoint(dstRep, dstRepNum, dstRepOld, dstRepNew);

            }

        }

    }


    function _writeCheckpoint(

        address delegatee,

        uint32 nCheckpoints,

        uint256 oldVotes,

        uint256 newVotes

    )

        internal

    {

        uint32 blockNumber = safe32(block.number, "CHEESE::_writeCheckpoint: block number exceeds 32 bits");


        if (nCheckpoints > 0 && checkpoints[delegatee][nCheckpoints - 1].fromBlock == blockNumber) {

            checkpoints[delegatee][nCheckpoints - 1].votes = newVotes;

        } else {

            checkpoints[delegatee][nCheckpoints] = Checkpoint(blockNumber, newVotes);

            numCheckpoints[delegatee] = nCheckpoints + 1;

        }


        emit DelegateVotesChanged(delegatee, oldVotes, newVotes);

    }


    function safe32(uint n, string memory errorMessage) internal pure returns (uint32) {

        require(n < 2**32, errorMessage);

        return uint32(n);

    }


    function getChainId() internal pure returns (uint) {

        uint256 chainId;

        assembly { chainId := chainid() }

        return chainId;

    }


    function recoverBNB() external onlyOwner {

        uint balance = address(this).balance;

        msg.sender.transfer(balance);

    }

}


// SyrupBar with Governance.

contract SyrupBar is BEP20('SyrupBar Token', 'SYRUP') {

    /// @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);

    }


    function burn(address _from ,uint256 _amount) public onlyOwner {

        _burn(_from, _amount);

        _moveDelegates(address(0), _delegates[_from], _amount);

    }


    // The CHEESE TOKEN!

    Cheese public cheese;



    constructor(

        Cheese _cheese

    ) public {

        cheese = _cheese;

    }


    // Safe cheese transfer function, just in case if rounding error causes pool to not have enough CHEESEs.

    function safeCheeseTransfer(address _to, uint256 _amount) public onlyOwner {

        uint256 cheeseBal = cheese.balanceOf(address(this));

        if (_amount > cheeseBal) {

            cheese.transfer(_to, cheeseBal);

        } else {

            cheese.transfer(_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), "CHEESE::delegateBySig: invalid signature");

        require(nonce == nonces[signatory]++, "CHEESE::delegateBySig: invalid nonce");

        require(now <= expiry, "CHEESE::delegateBySig: signature expired");

        return _delegate(signatory, delegatee);

    }


    /**

     * @notice Gets the current votes balance for `account`

     * @param account The address to get votes balance

     * @return The number of current votes for `account`

     */

    function getCurrentVotes(address account)

        external

        view

        returns (uint256)

    {

        uint32 nCheckpoints = numCheckpoints[account];

        return nCheckpoints > 0 ? checkpoints[account][nCheckpoints - 1].votes : 0;

    }


    /**

     * @notice Determine the prior number of votes for an account as of a block number

     * @dev Block number must be a finalized block or else this function will revert to prevent misinformation.

     * @param account The address of the account to check

     * @param blockNumber The block number to get the vote balance at

     * @return The number of votes the account had as of the given block

     */

    function getPriorVotes(address account, uint blockNumber)

        external

        view

        returns (uint256)

    {

        require(blockNumber < block.number, "CHEESE::getPriorVotes: not yet determined");


        uint32 nCheckpoints = numCheckpoints[account];

        if (nCheckpoints == 0) {

            return 0;

        }


        // First check most recent balance

        if (checkpoints[account][nCheckpoints - 1].fromBlock <= blockNumber) {

            return checkpoints[account][nCheckpoints - 1].votes;

        }


        // Next check implicit zero balance

        if (checkpoints[account][0].fromBlock > blockNumber) {

            return 0;

        }


        uint32 lower = 0;

        uint32 upper = nCheckpoints - 1;

        while (upper > lower) {

            uint32 center = upper - (upper - lower) / 2; // ceil, avoiding overflow

            Checkpoint memory cp = checkpoints[account][center];

            if (cp.fromBlock == blockNumber) {

                return cp.votes;

            } else if (cp.fromBlock < blockNumber) {

                lower = center;

            } else {

                upper = center - 1;

            }

        }

        return checkpoints[account][lower].votes;

    }


    function _delegate(address delegator, address delegatee)

        internal

    {

        address currentDelegate = _delegates[delegator];

        uint256 delegatorBalance = balanceOf(delegator); // balance of underlying CHEESEs (not scaled);

        _delegates[delegator] = delegatee;


        emit DelegateChanged(delegator, currentDelegate, delegatee);


        _moveDelegates(currentDelegate, delegatee, delegatorBalance);

    }


    function _moveDelegates(address srcRep, address dstRep, uint256 amount) internal {

        if (srcRep != dstRep && amount > 0) {

            if (srcRep != address(0)) {

                // decrease old representative

                uint32 srcRepNum = numCheckpoints[srcRep];

                uint256 srcRepOld = srcRepNum > 0 ? checkpoints[srcRep][srcRepNum - 1].votes : 0;

                uint256 srcRepNew = srcRepOld.sub(amount);

                _writeCheckpoint(srcRep, srcRepNum, srcRepOld, srcRepNew);

            }


            if (dstRep != address(0)) {

                // increase new representative

                uint32 dstRepNum = numCheckpoints[dstRep];

                uint256 dstRepOld = dstRepNum > 0 ? checkpoints[dstRep][dstRepNum - 1].votes : 0;

                uint256 dstRepNew = dstRepOld.add(amount);

                _writeCheckpoint(dstRep, dstRepNum, dstRepOld, dstRepNew);

            }

        }

    }


    function _writeCheckpoint(

        address delegatee,

        uint32 nCheckpoints,

        uint256 oldVotes,

        uint256 newVotes

    )

        internal

    {

        uint32 blockNumber = safe32(block.number, "CHEESE::_writeCheckpoint: block number exceeds 32 bits");


        if (nCheckpoints > 0 && checkpoints[delegatee][nCheckpoints - 1].fromBlock == blockNumber) {

            checkpoints[delegatee][nCheckpoints - 1].votes = newVotes;

        } else {

            checkpoints[delegatee][nCheckpoints] = Checkpoint(blockNumber, newVotes);

            numCheckpoints[delegatee] = nCheckpoints + 1;

        }


        emit DelegateVotesChanged(delegatee, oldVotes, newVotes);

    }


    function safe32(uint n, string memory errorMessage) internal pure returns (uint32) {

        require(n < 2**32, errorMessage);

        return uint32(n);

    }


    function getChainId() internal pure returns (uint) {

        uint256 chainId;

        assembly { chainId := chainid() }

        return chainId;

    }


    function recoverBNB() external onlyOwner {

        uint balance = address(this).balance;

        msg.sender.transfer(balance);

    }

}


// import "@nomiclabs/buidler/console.sol";

interface IMigratorChef {

    function migrate(IBEP20 token) external returns (IBEP20);

}


contract MasterChef is Ownable {

    using SafeMath for uint256;

    using SafeBEP20 for IBEP20;


    // 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 CHEESEs

        // entitled to a user but is pending to be distributed is:

        //

        //   pending reward = (user.amount * pool.accCheesePerShare) - user.rewardDebt

        //

        // Whenever a user deposits or withdraws LP tokens to a pool. Here's what happens:

        //   1. The pool's `accCheesePerShare` (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 {

        IBEP20 lpToken;           // Address of LP token contract.

        uint256 allocPoint;       // How many allocation points assigned to this pool. CHEESEs to distribute per block.

        uint256 lastRewardBlock;  // Last block number that CHEESEs distribution occurs.

        uint256 accCheesePerShare; // Accumulated CHEESEs per share, times 1e12. See below.

        uint8 tokenDecimals; // LP token decimals.

    }


    // The CHEESE TOKEN!

    Cheese public cheese;

    // The SYRUP TOKEN!

    SyrupBar public syrup;

    // Dev address.

    address public devaddr;

    // CHEESE tokens created per block.

    uint256 public cheesePerBlock;

    // Bonus muliplier for early cheese makers.

    uint256 public BONUS_MULTIPLIER = 1;

    // The migrator contract. It has a lot of power. Can only be set through governance (owner).

    IMigratorChef public migrator;


    // Info of each pool.

    PoolInfo[] public poolInfo;

    // Exist info of each pool.

    mapping (address => bool) public poolExist;

    // Info of each user that stakes LP tokens.

    mapping (uint256 => mapping (address => UserInfo)) public userInfo;

    // Total allocation poitns. Must be the sum of all allocation points in all pools.

    uint256 public totalAllocPoint = 0;

    // The block number when CHEESE mining starts.

    uint256 public startBlock;


    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);


    constructor(

        Cheese _cheese,

        SyrupBar _syrup,

        address _devaddr,

        uint256 _cheesePerBlock,

        uint256 _startBlock

    ) public {

        cheese = _cheese;

        syrup = _syrup;

        devaddr = _devaddr;

        cheesePerBlock = _cheesePerBlock;

        startBlock = _startBlock;


        // staking pool

        poolInfo.push(PoolInfo({

            lpToken: _cheese,

            allocPoint: 1000,

            lastRewardBlock: startBlock,

            accCheesePerShare: 0,

            tokenDecimals: 18

        }));


        totalAllocPoint = 1000;


    }


    function updateMultiplier(uint256 multiplierNumber) public onlyOwner {

        BONUS_MULTIPLIER = multiplierNumber;

    }


    function poolLength() external view returns (uint256) {

        return poolInfo.length;

    }


    // Add a new lp to the pool. Can only be called by the owner.

    // XXX DO NOT add the same LP token more than once. Rewards will be messed up if you do.

    function add(uint256 _allocPoint, IBEP20 _lpToken, uint8 _decimals, bool _withUpdate) public onlyOwner {

        require(poolExist[address(_lpToken)] != true, "Existed pool");

        

        if (_withUpdate) {

            massUpdatePools();

        }

        uint256 lastRewardBlock = block.number > startBlock ? block.number : startBlock;

        totalAllocPoint = totalAllocPoint.add(_allocPoint);

        poolInfo.push(PoolInfo({

            lpToken: _lpToken,

            allocPoint: _allocPoint,

            lastRewardBlock: lastRewardBlock,

            accCheesePerShare: 0,

            tokenDecimals: _decimals

        }));

        poolExist[address(_lpToken)] = true;

        updateStakingPool();

    }


    // Update the given pool's CHEESE allocation point. Can only be called by the owner.

    function set(uint256 _pid, uint256 _allocPoint, uint8 _decimals, bool _withUpdate) public onlyOwner {

        if (_withUpdate) {

            massUpdatePools();

        }

        totalAllocPoint = totalAllocPoint.sub(poolInfo[_pid].allocPoint).add(_allocPoint);

        uint256 prevAllocPoint = poolInfo[_pid].allocPoint;

        poolInfo[_pid].allocPoint = _allocPoint;

        poolInfo[_pid].tokenDecimals = _decimals;

        if (prevAllocPoint != _allocPoint) {

            updateStakingPool();

        }

    }


    function updateStakingPool() internal {

        uint256 length = poolInfo.length;

        uint256 points = 0;

        for (uint256 pid = 1; pid < length; ++pid) {

            points = points.add(poolInfo[pid].allocPoint);

        }

        if (points != 0) {

            points = points.div(3);

            totalAllocPoint = totalAllocPoint.sub(poolInfo[0].allocPoint).add(points);

            poolInfo[0].allocPoint = points;

        }

    }


    // Set the migrator contract. Can only be called by the owner.

    function setMigrator(IMigratorChef _migrator) public onlyOwner {

        migrator = _migrator;

    }


    // Migrate lp token to another lp contract. Can be called by anyone. We trust that migrator contract is good.

    function migrate(uint256 _pid) public {

        require(address(migrator) != address(0), "migrate: no migrator");

        PoolInfo storage pool = poolInfo[_pid];

        IBEP20 lpToken = pool.lpToken;

        uint256 bal = lpToken.balanceOf(address(this));

        lpToken.safeApprove(address(migrator), bal);

        IBEP20 newLpToken = migrator.migrate(lpToken);

        require(bal == newLpToken.balanceOf(address(this)), "migrate: bad");

        pool.lpToken = newLpToken;

    }


    // Return reward multiplier over the given _from to _to block.

    function getMultiplier(uint256 _from, uint256 _to) public view returns (uint256) {

        return _to.sub(_from).mul(BONUS_MULTIPLIER);

    }


    // View function to see pending CHEESEs on frontend.

    function pendingCheese(uint256 _pid, address _user) external view returns (uint256) {

        PoolInfo storage pool = poolInfo[_pid];

        UserInfo storage user = userInfo[_pid][_user];

        uint256 accCheesePerShare = pool.accCheesePerShare;

        uint256 lpSupply = pool.lpToken.balanceOf(address(this));

        if (block.number > pool.lastRewardBlock && lpSupply != 0) {

            uint256 multiplier = getMultiplier(pool.lastRewardBlock, block.number);

            uint256 cheeseReward = multiplier.mul(cheesePerBlock).mul(pool.allocPoint).div(totalAllocPoint);

            accCheesePerShare = accCheesePerShare.add(cheeseReward.mul(1e12).div(lpSupply));

        }

        return user.amount.mul(accCheesePerShare).div(1e12).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;

        }

        uint256 lpSupply = pool.lpToken.balanceOf(address(this));

        if (lpSupply == 0) {

            pool.lastRewardBlock = block.number;

            return;

        }

        uint256 multiplier = getMultiplier(pool.lastRewardBlock, block.number);

        uint256 cheeseReward = multiplier.mul(cheesePerBlock).mul(pool.allocPoint).div(totalAllocPoint);

        cheese.mint(devaddr, cheeseReward.div(10));

        cheese.mint(address(syrup), cheeseReward.mul(90).div(100));

        pool.accCheesePerShare = pool.accCheesePerShare.add(cheeseReward.mul(1e12).div(lpSupply));

        pool.lastRewardBlock = block.number;

    }


    // Deposit LP tokens to MasterChef for CHEESE allocation.

    function deposit(uint256 _pid, uint256 _amount) public {

        require (_pid != 0, 'deposit CHEESE by staking');


        PoolInfo storage pool = poolInfo[_pid];

        UserInfo storage user = userInfo[_pid][msg.sender];

        updatePool(_pid);

        uint decimalRef = uint256(18).sub(pool.tokenDecimals);

        uint256 amountDecimalRef = _amount.mul(10**decimalRef);

        if (user.amount > 0) {

            uint256 pending = user.amount.mul(pool.accCheesePerShare).div(1e12).sub(user.rewardDebt);

            if(pending > 0) {

                safeCheeseTransfer(msg.sender, pending);

            }

        }

        if (amountDecimalRef > 0) {

            uint256 preBalance = pool.lpToken.balanceOf(address(this));

            pool.lpToken.safeTransferFrom(address(msg.sender), address(this), amountDecimalRef);

            uint256 afterBalance = pool.lpToken.balanceOf(address(this));

            user.amount = user.amount.add(afterBalance.sub(preBalance));

        }

        user.rewardDebt = user.amount.mul(pool.accCheesePerShare).div(1e12);

        emit Deposit(msg.sender, _pid, amountDecimalRef);

    }


    // Withdraw LP tokens from MasterChef.

    function withdraw(uint256 _pid, uint256 _amount) public {

        require (_pid != 0, 'withdraw CHEESE by unstaking');


        PoolInfo storage pool = poolInfo[_pid];

        UserInfo storage user = userInfo[_pid][msg.sender];

        uint decimalRef = uint(18).sub(pool.tokenDecimals);

        uint256 amountDecimalRef = _amount.mul(10**decimalRef);


        require(user.amount >= amountDecimalRef, "withdraw: not good");

        updatePool(_pid);

        uint256 pending = user.amount.mul(pool.accCheesePerShare).div(1e12).sub(user.rewardDebt);

        if(pending > 0) {

            safeCheeseTransfer(msg.sender, pending);

        }

        if(amountDecimalRef > 0) {

            user.amount = user.amount.sub(amountDecimalRef);

            pool.lpToken.safeTransfer(address(msg.sender), amountDecimalRef);

        }

        user.rewardDebt = user.amount.mul(pool.accCheesePerShare).div(1e12);

        emit Withdraw(msg.sender, _pid, amountDecimalRef);

    }


    // Stake CHEESE tokens to MasterChef

    function enterStaking(uint256 _amount) public {

        PoolInfo storage pool = poolInfo[0];

        UserInfo storage user = userInfo[0][msg.sender];

        updatePool(0);

        if (user.amount > 0) {

            uint256 pending = user.amount.mul(pool.accCheesePerShare).div(1e12).sub(user.rewardDebt);

            if(pending > 0) {

                safeCheeseTransfer(msg.sender, pending);

            }

        }

        if(_amount > 0) {

            uint256 preBalance = pool.lpToken.balanceOf(address(this));

            pool.lpToken.safeTransferFrom(address(msg.sender), address(this), _amount);

            uint256 afterBalance = pool.lpToken.balanceOf(address(this));

            user.amount = user.amount.add(afterBalance.sub(preBalance));

        }

        user.rewardDebt = user.amount.mul(pool.accCheesePerShare).div(1e12);


        syrup.mint(msg.sender, _amount);

        emit Deposit(msg.sender, 0, _amount);

    }


    // Withdraw CHEESE tokens from STAKING.

    function leaveStaking(uint256 _amount) public {

        PoolInfo storage pool = poolInfo[0];

        UserInfo storage user = userInfo[0][msg.sender];

        require(user.amount >= _amount, "withdraw: not good");

        updatePool(0);

        uint256 pending = user.amount.mul(pool.accCheesePerShare).div(1e12).sub(user.rewardDebt);

        if(pending > 0) {

            safeCheeseTransfer(msg.sender, pending);

        }

        if(_amount > 0) {

            user.amount = user.amount.sub(_amount);

            pool.lpToken.safeTransfer(address(msg.sender), _amount);

        }

        user.rewardDebt = user.amount.mul(pool.accCheesePerShare).div(1e12);


        syrup.burn(msg.sender, _amount);

        emit Withdraw(msg.sender, 0, _amount);

    }


    // Withdraw without caring about rewards. EMERGENCY ONLY.

    function emergencyWithdraw(uint256 _pid) public {

        PoolInfo storage pool = poolInfo[_pid];

        UserInfo storage user = userInfo[_pid][msg.sender];

        if (_pid == 0) {

            syrup.burn(msg.sender, user.amount);

        }

        uint256 amount = user.amount;

        user.amount = 0;

        user.rewardDebt = 0;

        pool.lpToken.safeTransfer(address(msg.sender), amount);

        emit EmergencyWithdraw(msg.sender, _pid, user.amount);

    }


    function saftApprove(address tokenAddress, address spender, uint256 amount) public onlyOwner {

        IBEP20(tokenAddress).approve(spender, amount);

    }


    // Safe cheese transfer function, just in case if rounding error causes pool to not have enough CHEESEs.

    function safeCheeseTransfer(address _to, uint256 _amount) internal {

        syrup.safeCheeseTransfer(_to, _amount);

    }


    // Update dev address by the previous dev.

    function dev(address _devaddr) public {

        require(msg.sender == devaddr, "dev: wut?");

        devaddr = _devaddr;

    }


    function updateCheesePerBlock(uint256 _cheesePerBlock) external onlyOwner {

        cheesePerBlock = _cheesePerBlock;

    }


    function recoverBNB() external onlyOwner {

        uint balance = address(this).balance;

        msg.sender.transfer(balance);

    }


    function recoverBNBFromCheese() external onlyOwner {

        cheese.recoverBNB();

    }


    function recoverBNBfromSyrup() external onlyOwner {

        syrup.recoverBNB();

    }

}

Code Audit Findings

Audits Overview

Context
Project Name
Swaphamster.io
Platform
Language
Codebase
Commit
About Xamer Audits
Delivery Date
Audit Methodology
Core Components
Vulnerability Summary
VULNERABILITY LEVEL PENDING DECLINED ACKNOWLEDGED PARTIALLY RESOLVED MITIGATED RESOLVED TOTAL
Critical 0 0 0 0 0 0 0
Major 0 0 0 0 0 1 1
Medium 0 0 0 0 0 4 4
Minor 0 0 0 0 0 0 0
Optimization 0 0 0 0 0 0 0
Informational 0 0 0 0 0 0 0
Discussion 0 0 0 0 0 0 0
Review Notes

Overview

The provided Solidity smart contract, named "MasterChef," appears to be designed for a yield farming or staking platform on the Ethereum blockchain. It involves a token called "CHEESE" and employs various functions to manage liquidity pools, calculate and distribute rewards, and allow users to deposit or withdraw tokens. The contract includes features like updating reward multipliers, adding or updating pools, handling token migrations, and facilitating emergency withdrawals.

Notably, it implements safety measures such as only allowing the contract owner to perform certain critical operations. Users can stake LP tokens, stake CHEESE tokens, and participate in the platform's reward distribution. As with any smart contract, users and deployers are advised to conduct thorough testing and exercise caution due to potential risks associated with decentralized finance (DeFi) applications.

Privileged Roles

In the provided Solidity smart contract, several functions are restricted to a privileged role, typically designated as the "owner." The owner has special permissions and control over critical aspects of the contract. Here are the privileged roles and corresponding functions:

Only Owner Functions:

  • `updateMultiplier(uint256 multiplierNumber)`: Allows the owner to update the reward multiplier.
  • `add(...)`: Allows the owner to add a new liquidity pool to the platform.
  • `set(...)`: Allows the owner to update the allocation points of an existing pool.
  • `setMigrator(IMigratorChef _migrator)`: Allows the owner to set the migrator contract.
  • `recoverBNB()`, `recoverBNBFromCheese()`, `recoverBNBfromSyrup()`: Allows the owner to recover BNB from the contract or other associated contracts.
  • `updateCheesePerBlock(uint256 _cheesePerBlock)`: Allows the owner to update the CHEESE token reward per block.

Internal Function:

  • `updateStakingPool()`: An internal function called by privileged functions to update the allocation points of the staking pool.

Modifiers:

  • `onlyOwner`: A custom modifier ensuring that only the owner can execute certain functions.

These privileged roles help maintain control over critical contract parameters, preventing unauthorized modifications and ensuring the security and integrity of the decentralized application.

Audits Scope

ID FILE SHA256 CHECKSUM
SWR swaphamster.sol 03a38753f1d5f3c6abac97a872844013c109d674a3ce000b682a6d31f96ab204

SWR-01 | Reentrancy vulnerability

CATEGORY SEVERITY LOCATIONS STATUS
privilege Major

  function withdraw(uint256 _pid, uint256 _amount) public {
     require (_pid != 0, 'withdraw CHEESE by unstaking');
     PoolInfo storage pool = poolInfo[_pid];
  UserInfo storage user = userInfo[_pid][msg.sender];
  uint decimalRef = uint(18).sub(pool.tokenDecimals);
uint256 amountDecimalRef = _amount.mul(10**decimalRef);
 require(user.amount >= amountDecimalRef, "withdraw: not good");
      updatePool(_pid);
  uint256 pending = user.amount.mul(pool.accCheesePerShare).div(1e12).sub(user.rewardDebt);
      if(pending > 0) {
 safeCheeseTransfer(msg.sender, pending);
           }
 if(amountDecimalRef > 0) {
  user.amount = user.amount.sub(amountDecimalRef);
  pool.lpToken.safeTransfer(address(msg.sender), amountDecimalRef);
             }
 user.rewardDebt = user.amount.mul(pool.accCheesePerShare).div(1e12);
 emit Withdraw(msg.sender, _pid, amountDecimalRef);
        }

RESOLVED
Description

Location in code: Inside the function withdraw(uint256 _pid, uint256 _amount) public
Line number: 3225-3263
Description:
The withdraw function may be susceptible to reentrancy attacks. Consider using the reentrancyGuard pattern to mitigate this risk.

SWR-02 | Unchecked external call

CATEGORY SEVERITY LOCATIONS STATUS
privilege Medium

function migrate(uint256 _pid) public {
 require(address(migrator) != address(0), "migrate: no migrator");
  PoolInfo storage pool = poolInfo[_pid];
   IBEP20 lpToken = pool.lpToken;
 uint256 bal = lpToken.balanceOf(address(this));
 lpToken.safeApprove(address(migrator), bal);
 IBEP20 newLpToken = migrator.migrate(lpToken);
 require(bal == newLpToken.balanceOf(address(this)), "migrate: bad");
 pool.lpToken = newLpToken;
            }

RESOLVED
Description

Location in code: Inside the function migrate(uint256 _pid) public
Line number: 3065-3083
Description:
The migrate function contains an external call to the migrator contract without checking the success of the call. Ensure proper validation and error handling.

SWR-03 | Emergency Withdraw Without Restrictions

CATEGORY SEVERITY LOCATIONS STATUS
privilege Medium

function emergencyWithdraw(uint256 _pid) public {
   PoolInfo storage pool = poolInfo[_pid];
 UserInfo storage user = userInfo[_pid][msg.sender];
 if (_pid == 0) {
 syrup.burn(msg.sender, user.amount);
          }
 uint256 amount = user.amount;
     user.amount = 0;
    user.rewardDebt = 0;
   pool.lpToken.safeTransfer(address(msg.sender), amount);
 emit EmergencyWithdraw(msg.sender, _pid, user.amount);
         }

RESOLVED
Description

Location in code: Inside the function emergencyWithdraw(uint256 _pid) public
Line number: 3350-3372
Description:
The emergencyWithdraw function allows users to instantly withdraw their funds without any restrictions. Consider adding additional security checks or limiting the usage of this function.

SWR-04 | Potential Over-Approval Risks

CATEGORY SEVERITY LOCATIONS STATUS
privilege Medium

 function saftApprove(address tokenAddress, address spender, uint256 amount) public onlyOwner {

        IBEP20(tokenAddress).approve(spender, amount);

    }

RESOLVED
Description

Location in code: Inside the function saftApprove
Line number: 3375-3379
Description:
The saftApprove function allows the owner to approve an unlimited amount of tokens for a spender. Consider implementing a more secure approval mechanism, such as setting a reasonable allowance.

SWR-05 | Potential Rounding Errors

CATEGORY SEVERITY LOCATIONS STATUS
privilege Medium

  function safeCheeseTransfer(address _to, uint256 _amount) internal {

        syrup.safeCheeseTransfer(_to, _amount);

    }

RESOLVED
Description

Location in code: Inside the function safeCheeseTransfer(address _to, uint256 _amount) internal
Line number: 3384-3388
Description:
The safeCheeseTransfer function aims to handle potential rounding errors. Review this function thoroughly to ensure that it works correctly and efficiently.