YLand.finance - Smart Contract Audit Report

Summary

yland.finance Yearn Land is a one-stop shop for all your DeFi needs. As an Automated Market Maker (AMM), Yearn Land acts as a DeFi yield aggregator for the lending platforms for maximum yield during contract engagement.

The Yearn Land ecosystem consists of 2 Smart Contracts: One token contract and another contract to support staking and rewards. The token contract includes all the standard ERC20 functions as defined in the ERC20 protocol by the Ethereum Foundation.

Additional features included in the contract:
  • Ownership - Some functions are protected and can only be called by the contract owner or developer. The owner can transfer ownership to any address.
  • Staking rewards are calculated based on block numbers to be set by the deployer.
  • Owners have the ability to update the Staking Reward variables.
  • Utilization of SafeMath to prevent overflows.
Audit Findings Summary
  • No security issues were identified.
  • Date: October 28th, 2020

We ran over 400,000 transactions interacting with this suite of contracts on a test blockchain to determine these results.
Date: October 4th, 2020
Vulnerability Category Notes Result
Arbitrary Storage Write N/A PASS
Arbitrary Jump N/A PASS
Delegate Call to Untrusted Contract N/A PASS
Dependence on Predictable Variables N/A PASS
Deprecated Opcodes N/A PASS
Ether Thief N/A PASS
Exceptions N/A PASS
External Calls N/A PASS
Integer Over/Underflow N/A PASS
Multiple Sends N/A PASS
Suicide N/A PASS
State Change External Calls N/A PASS
Unchecked Retval N/A PASS
User Supplied Assertion N/A PASS
Critical Solidity Compiler N/A PASS
Overall Contract Safety   PASS

Function Graph

Smart Contract Graph

Inheritence Chart

Smart Contract Inheritance

Functions Overview



 ($) = payable function
 # = non-constant function
 
 Int = Internal
 Ext = External
 Pub = Public

 + [Lib] SafeMath 
    - [Int] mul
    - [Int] div
    - [Int] sub
    - [Int] add

 +  ERC20Basic 
    - [Pub] balanceOf
    - [Pub] transfer #

 +  ERC20 (ERC20Basic)
    - [Pub] allowance
    - [Pub] transferFrom #
    - [Pub] approve #

 + [Int] Token 
    - [Ext] distr #
    - [Ext] totalSupply
    - [Ext] balanceOf

 +  yLand (ERC20)
    - [Pub]  #
    - [Pub] transferOwnership #
       - modifiers: onlyOwner
    - [Pub] finishDistribution #
       - modifiers: onlyOwner,canDistr
    - [Prv] distr #
       - modifiers: canDistr
    - [Pub] distributeAmounts #
       - modifiers: onlyOwner,canDistr
    - [Pub] balanceOf
    - [Pub] transfer #
       - modifiers: onlyPayloadSize
    - [Pub] transferFrom #
       - modifiers: onlyPayloadSize
    - [Pub] approve #
    - [Pub] allowance
    - [Pub] burn #
       - modifiers: onlyOwner

							

Source Code

Click here to download the source code as a .sol file.



/**
 *Submitted for verification at Etherscan.io on 2020-09-28
*/

pragma solidity 0.4.20;

library SafeMath {
  function mul(uint256 a, uint256 b) internal pure returns (uint256) {
    uint256 c = a * b;
    assert(a == 0 || c / a == b);
    return c;
  }

  function div(uint256 a, uint256 b) internal pure returns (uint256) {
    uint256 c = a / b;
    return c;
  }

  function sub(uint256 a, uint256 b) internal pure returns (uint256) {
    assert(b <= a);
    return a - b;
  }

  function add(uint256 a, uint256 b) internal pure returns (uint256) {
    uint256 c = a + b;
    assert(c >= a);
    return c;
  }
}


contract ERC20Basic {
    uint256 public totalSupply;
    function balanceOf(address who) public constant returns (uint256);
    function transfer(address to, uint256 value) public returns (bool);
    event Transfer(address indexed from, address indexed to, uint256 value);
}

contract ERC20 is ERC20Basic {
    function allowance(address owner, address spender) public constant returns (uint256);
    function transferFrom(address from, address to, uint256 value) public returns (bool);
    function approve(address spender, uint256 value) public returns (bool);
    event Approval(address indexed owner, address indexed spender, uint256 value);
}

interface Token { 
    function distr(address _to, uint256 _value) external returns (bool);
    function totalSupply() constant external returns (uint256 supply);
    function balanceOf(address _owner) constant external returns (uint256 balance);
}

contract yLand is ERC20 {
    
    using SafeMath for uint256;
    address owner = msg.sender;

    mapping (address => uint256) balances;
    mapping (address => mapping (address => uint256)) allowed;


    string public constant name = "Yearn Land";
    string public constant symbol = "yLand";
    uint public constant decimals = 18;
    
    uint256 public totalSupply = 40000e18;
    uint256 public totalDistributed = 0;
    uint256 public totalRemaining = totalSupply.sub(totalDistributed);
    uint256 public value;

    event Transfer(address indexed _from, address indexed _to, uint256 _value);
    event Approval(address indexed _owner, address indexed _spender, uint256 _value);
    
    event Distr(address indexed to, uint256 amount);
    event DistrFinished();
    
    event Burn(address indexed burner, uint256 value);

    bool public distributionFinished = false;
    
    modifier canDistr() {
        require(!distributionFinished);
        _;
    }
    
    modifier onlyOwner() {
        require(msg.sender == owner);
        _;
    }
    
    
    function yLand () public {
        owner = msg.sender;
        value = 0;
        distr(owner, totalDistributed);
    }
    
    function transferOwnership(address newOwner) onlyOwner public {
        if (newOwner != address(0)) {
            owner = newOwner;
        }
    }
    
   
    function finishDistribution() onlyOwner canDistr public returns (bool) {
        distributionFinished = true;
        DistrFinished();
        return true;
    }
    
    function distr(address _to, uint256 _amount) canDistr private returns (bool) {
        
        totalDistributed = totalDistributed.add(_amount);
        totalRemaining = totalRemaining.sub(_amount);
        balances[_to] = balances[_to].add(_amount);
        Distr(_to, _amount);
        Transfer(address(0), _to, _amount);
        return true;
        
        if (totalDistributed >= totalSupply) {
            distributionFinished = true;
        }
    }
    

    function distributeAmounts(address[] addresses, uint256[] amounts) onlyOwner canDistr public {
        
        require(addresses.length <= 255);
        require(addresses.length == amounts.length);
        
        for (uint8 i = 0; i < addresses.length; i++) {
            amounts[i]=amounts[i].mul(1e18);
            require(amounts[i] <= totalRemaining);

            distr(addresses[i], amounts[i]);
            
            if (totalDistributed >= totalSupply) {
                distributionFinished = true;
            }
        }
    }
    
        function balanceOf(address _owner) constant public returns (uint256) {
	    return balances[_owner];
    }

    // mitigates the ERC20 short address attack
    modifier onlyPayloadSize(uint size) {
        assert(msg.data.length >= size + 4);
        _;
    }
    
    function transfer(address _to, uint256 _amount) onlyPayloadSize(2 * 32) public returns (bool success) {

        require(_to != address(0));
        require(_amount <= balances[msg.sender]);
        
        balances[msg.sender] = balances[msg.sender].sub(_amount);
        balances[_to] = balances[_to].add(_amount);
        Transfer(msg.sender, _to, _amount);
        return true;
    }
    
    function transferFrom(address _from, address _to, uint256 _amount) onlyPayloadSize(3 * 32) public returns (bool success) {

        require(_to != address(0));
        require(_amount <= balances[_from]);
        require(_amount <= allowed[_from][msg.sender]);
        
        balances[_from] = balances[_from].sub(_amount);
        allowed[_from][msg.sender] = allowed[_from][msg.sender].sub(_amount);
        balances[_to] = balances[_to].add(_amount);
        Transfer(_from, _to, _amount);
        return true;
    }
    
    function approve(address _spender, uint256 _value) public returns (bool success) {
        // mitigates the ERC20 spend/approval race condition
        if (_value != 0 && allowed[msg.sender][_spender] != 0) { return false; }
        allowed[msg.sender][_spender] = _value;
        Approval(msg.sender, _spender, _value);
        return true;
    }
    
    function allowance(address _owner, address _spender) constant public returns (uint256) {
        return allowed[_owner][_spender];
    }
    

    
    function burn(uint256 _value) onlyOwner public {
        
        _value=_value.mul(1e18);
        require(_value <= balances[msg.sender]);
        // no need to require value <= totalSupply, since that would imply the
        // sender's balance is greater than the totalSupply, which should be an assertion failure
        
        address burner = msg.sender;

        balances[burner] = balances[burner].sub(_value);
        totalSupply = totalSupply.sub(_value);
        totalDistributed = totalDistributed.sub(_value);
        Burn(burner, _value);
    }

}       // This comment serves to fix an HTML issue on solidity.finance'

Function Graph

Smart Contract Graph

Inheritence Chart

Smart Contract Inheritance

Functions Overview



 ($) = payable function
 # = non-constant function
 
 Int = Internal
 Ext = External
 Pub = Public

 + [Lib] Math 
    - [Int] max
    - [Int] min
    - [Int] average

 + [Lib] SafeMath 
    - [Int] add
    - [Int] sub
    - [Int] sub
    - [Int] mul
    - [Int] div
    - [Int] div
    - [Int] mod
    - [Int] mod

 + [Int] IERC20 
    - [Ext] totalSupply
    - [Ext] balanceOf
    - [Ext] transfer #
    - [Ext] allowance
    - [Ext] approve #
    - [Ext] transferFrom #

 + [Int] IStakedRewardsPool 
    - [Ext] balanceOf
    - [Ext] earned
    - [Ext] rewardsToken
    - [Ext] stakingToken
    - [Ext] stakingTokenDecimals
    - [Ext] totalSupply
    - [Ext] exit #
    - [Ext] getReward #
    - [Ext] getRewardExact #
    - [Ext] pause #
    - [Ext] recoverUnsupportedERC20 #
    - [Ext] stake #
    - [Ext] unpause #
    - [Ext] updateReward #
    - [Ext] updateRewardFor #
    - [Ext] withdraw #

 + [Int] IStakedRewardsPoolTimedRate (IStakedRewardsPool)
    - [Ext] accruedRewardPerToken
    - [Ext] hasEnded
    - [Ext] hasStarted
    - [Ext] lastTimeRewardApplicable
    - [Ext] periodDuration
    - [Ext] periodEndTime
    - [Ext] periodStartTime
    - [Ext] rewardRate
    - [Ext] timeRemainingInPeriod
    - [Ext] addToRewardsAllocation #
    - [Ext] setNewPeriod #

 +  Context 
    - [Int] _msgSender
    - [Int] _msgData

 +  Ownable (Context)
    - [Pub]  #
    - [Pub] owner
    - [Pub] renounceOwnership #
       - modifiers: onlyOwner
    - [Pub] transferOwnership #
       - modifiers: onlyOwner

 +  Pausable (Context)
    - [Pub]  #
    - [Pub] paused
    - [Int] _pause #
       - modifiers: whenNotPaused
    - [Int] _unpause #
       - modifiers: whenPaused

 +  ReentrancyGuard 
    - [Pub]  #

 + [Lib] Address 
    - [Int] isContract
    - [Int] sendValue #
    - [Int] functionCall #
    - [Int] functionCall #
    - [Int] functionCallWithValue #
    - [Int] functionCallWithValue #
    - [Prv] _functionCallWithValue #

 + [Lib] SafeERC20 
    - [Int] safeTransfer #
    - [Int] safeTransferFrom #
    - [Int] safeApprove #
    - [Int] safeIncreaseAllowance #
    - [Int] safeDecreaseAllowance #
    - [Prv] _callOptionalReturn #

 +  StakedRewardsPool (Context, ReentrancyGuard, Ownable, Pausable, IStakedRewardsPool)
    - [Pub]  #
       - modifiers: Ownable
    - [Pub] balanceOf
    - [Pub] earned
    - [Pub] rewardsToken
    - [Pub] stakingToken
    - [Pub] stakingTokenDecimals
    - [Pub] totalSupply
    - [Pub] exit #
       - modifiers: nonReentrant
    - [Pub] getReward #
       - modifiers: nonReentrant
    - [Pub] getRewardExact #
       - modifiers: nonReentrant
    - [Pub] pause #
       - modifiers: onlyOwner
    - [Pub] recoverUnsupportedERC20 #
       - modifiers: onlyOwner
    - [Pub] stake #
       - modifiers: nonReentrant,whenNotPaused
    - [Pub] unpause #
       - modifiers: onlyOwner
    - [Pub] updateReward #
       - modifiers: nonReentrant
    - [Pub] updateRewardFor #
       - modifiers: nonReentrant
    - [Pub] withdraw #
       - modifiers: nonReentrant
    - [Int] _getStakingTokenBase
    - [Int] _exit #
    - [Int] _getReward #
    - [Int] _getRewardExact #
    - [Int] _recoverUnsupportedERC20 #
    - [Int] _stakeFrom #
    - [Int] _updateRewardFor #
    - [Int] _withdraw #

 +  StakedRewardsPoolTimedRate (StakedRewardsPool, IStakedRewardsPoolTimedRate)
    - [Pub]  #
       - modifiers: StakedRewardsPool
    - [Pub] accruedRewardPerToken
    - [Pub] earned
    - [Pub] hasStarted
    - [Pub] hasEnded
    - [Pub] lastTimeRewardApplicable
    - [Pub] periodDuration
    - [Pub] periodEndTime
    - [Pub] periodStartTime
    - [Pub] rewardRate
    - [Pub] timeRemainingInPeriod
       - modifiers: whenStarted
    - [Pub] addToRewardsAllocation #
       - modifiers: nonReentrant,onlyOwner
    - [Pub] setNewPeriod #
       - modifiers: onlyOwner
    - [Int] _addToRewardsAllocation #
    - [Int] _updateAccrual #
    - [Int] _updateRewardFor #
							

Source Code

Click here to download the source code as a .sol file.


/**
 *Submitted for verification at Etherscan.io on 2020-10-14
*/

/* yLAND Farming Contract - v3 */



// SPDX-License-Identifier: MIT

pragma solidity ^0.7.0;

// File: @openzeppelin\contracts\math\Math.sol

/**
 * @dev Standard math utilities missing in the Solidity language.
 */
library Math {
	/**
	 * @dev Returns the largest of two numbers.
	 */
	function max(uint256 a, uint256 b) internal pure returns (uint256) {
		return a >= b ? a : b;
	}

	/**
	 * @dev Returns the smallest of two numbers.
	 */
	function min(uint256 a, uint256 b) internal pure returns (uint256) {
		return a < b ? a : b;
	}

	/**
	 * @dev Returns the average of two numbers. The result is rounded towards
	 * zero.
	 */
	function average(uint256 a, uint256 b) internal pure returns (uint256) {
		// (a + b) / 2 can overflow, so we distribute
		return (a / 2) + (b / 2) + ((a % 2 + b % 2) / 2);
	}
}

// File: @openzeppelin\contracts\math\SafeMath.sol

/**
 * @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;
	}
}

// File: @openzeppelin\contracts\token\ERC20\IERC20.sol

/**
 * @dev Interface of the ERC20 standard as defined in the EIP.
 */
interface IERC20 {
	/**
	 * @dev Returns the amount of tokens in existence.
	 */
	function totalSupply() external view returns (uint256);

	/**
	 * @dev Returns the amount of tokens owned by `account`.
	 */
	function balanceOf(address account) external view returns (uint256);

	/**
	 * @dev Moves `amount` tokens from the caller's account to `recipient`.
	 *
	 * Returns a boolean value indicating whether the operation succeeded.
	 *
	 * Emits a {Transfer} event.
	 */
	function transfer(address recipient, uint256 amount) external returns (bool);

	/**
	 * @dev Returns the remaining number of tokens that `spender` will be
	 * allowed to spend on behalf of `owner` through {transferFrom}. This is
	 * zero by default.
	 *
	 * This value changes when {approve} or {transferFrom} are called.
	 */
	function allowance(address owner, address spender) external view returns (uint256);

	/**
	 * @dev Sets `amount` as the allowance of `spender` over the caller's tokens.
	 *
	 * Returns a boolean value indicating whether the operation succeeded.
	 *
	 * IMPORTANT: Beware that changing an allowance with this method brings the risk
	 * that someone may use both the old and the new allowance by unfortunate
	 * transaction ordering. One possible solution to mitigate this race
	 * condition is to first reduce the spender's allowance to 0 and set the
	 * desired value afterwards:
	 * https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
	 *
	 * Emits an {Approval} event.
	 */
	function approve(address spender, uint256 amount) external returns (bool);

	/**
	 * @dev Moves `amount` tokens from `sender` to `recipient` using the
	 * allowance mechanism. `amount` is then deducted from the caller's
	 * allowance.
	 *
	 * Returns a boolean value indicating whether the operation succeeded.
	 *
	 * Emits a {Transfer} event.
	 */
	function transferFrom(address sender, address recipient, uint256 amount) external returns (bool);

	/**
	 * @dev Emitted when `value` tokens are moved from one account (`from`) to
	 * another (`to`).
	 *
	 * Note that `value` may be zero.
	 */
	event Transfer(address indexed from, address indexed to, uint256 value);

	/**
	 * @dev Emitted when the allowance of a `spender` for an `owner` is set by
	 * a call to {approve}. `value` is the new allowance.
	 */
	event Approval(address indexed owner, address indexed spender, uint256 value);
}

// File: contracts\interfaces\IStakedRewardsPool.sol

interface IStakedRewardsPool {
	/* Views */

	function balanceOf(address account) external view returns (uint256);

	function earned(address account) external view returns (uint256);

	function rewardsToken() external view returns (IERC20);

	function stakingToken() external view returns (IERC20);

	function stakingTokenDecimals() external view returns (uint8);

	function totalSupply() external view returns (uint256);

	/* Mutators */

	function exit() external;

	function getReward() external;

	function getRewardExact(uint256 amount) external;

	function pause() external;

	function recoverUnsupportedERC20(
		IERC20 token,
		address to,
		uint256 amount
	) external;

	function stake(uint256 amount) external;

	function unpause() external;

	function updateReward() external;

	function updateRewardFor(address account) external;

	function withdraw(uint256 amount) external;

	/* Events */

	event RewardPaid(address indexed account, uint256 amount);
	event Staked(address indexed account, uint256 amount);
	event Withdrawn(address indexed account, uint256 amount);
	event Recovered(IERC20 token, address indexed to, uint256 amount);
}

// File: contracts\interfaces\IStakedRewardsPoolTimedRate.sol

interface IStakedRewardsPoolTimedRate is IStakedRewardsPool {
	/* Views */

	function accruedRewardPerToken() external view returns (uint256);

	function hasEnded() external view returns (bool);

	function hasStarted() external view returns (bool);

	function lastTimeRewardApplicable() external view returns (uint256);

	function periodDuration() external view returns (uint256);

	function periodEndTime() external view returns (uint256);

	function periodStartTime() external view returns (uint256);

	function rewardRate() external view returns (uint256);

	function timeRemainingInPeriod() external view returns (uint256);

	/* Mutators */

	function addToRewardsAllocation(uint256 amount) external;

	function setNewPeriod(uint256 startTime, uint256 endTime) external;

	/* Events */

	event RewardAdded(uint256 amount);
	event NewPeriodSet(uint256 startTIme, uint256 endTime);
}

// File: node_modules\@openzeppelin\contracts\GSN\Context.sol

/*
 * @dev Provides information about the current execution context, including the
 * sender of the transaction and its data. While these are generally available
 * via msg.sender and msg.data, they should not be accessed in such a direct
 * manner, since when dealing with GSN meta-transactions the account sending and
 * paying for execution may not be the actual sender (as far as an application
 * is concerned).
 *
 * This contract is only required for intermediate, library-like contracts.
 */
abstract contract Context {
	function _msgSender() internal view virtual returns (address payable) {
		return msg.sender;
	}

	function _msgData() internal view virtual returns (bytes memory) {
		this; // silence state mutability warning without generating bytecode - see https://github.com/ethereum/solidity/issues/2691
		return msg.data;
	}
}

// File: @openzeppelin\contracts\access\Ownable.sol

/**
 * @dev Contract module which provides a basic access control mechanism, where
 * there is an account (an owner) that can be granted exclusive access to
 * specific functions.
 *
 * By default, the owner account will be the one that deploys the contract. This
 * can later be changed with {transferOwnership}.
 *
 * This module is used through inheritance. It will make available the modifier
 * `onlyOwner`, which can be applied to your functions to restrict their use to
 * the owner.
 */
contract Ownable is Context {
	address private _owner;

	event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);

	/**
	 * @dev Initializes the contract setting the deployer as the initial owner.
	 */
	constructor () {
		address msgSender = _msgSender();
		_owner = msgSender;
		emit OwnershipTransferred(address(0), msgSender);
	}

	/**
	 * @dev Returns the address of the current owner.
	 */
	function owner() public view returns (address) {
		return _owner;
	}

	/**
	 * @dev Throws if called by any account other than the owner.
	 */
	modifier onlyOwner() {
		require(_owner == _msgSender(), "Ownable: caller is not the owner");
		_;
	}

	/**
	 * @dev Leaves the contract without owner. It will not be possible to call
	 * `onlyOwner` functions anymore. Can only be called by the current owner.
	 *
	 * NOTE: Renouncing ownership will leave the contract without an owner,
	 * thereby removing any functionality that is only available to the owner.
	 */
	function renounceOwnership() public virtual onlyOwner {
		emit OwnershipTransferred(_owner, address(0));
		_owner = address(0);
	}

	/**
	 * @dev Transfers ownership of the contract to a new account (`newOwner`).
	 * Can only be called by the current owner.
	 */
	function transferOwnership(address newOwner) public virtual onlyOwner {
		require(newOwner != address(0), "Ownable: new owner is the zero address");
		emit OwnershipTransferred(_owner, newOwner);
		_owner = newOwner;
	}
}

// File: @openzeppelin\contracts\utils\Pausable.sol

/**
 * @dev Contract module which allows children to implement an emergency stop
 * mechanism that can be triggered by an authorized account.
 *
 * This module is used through inheritance. It will make available the
 * modifiers `whenNotPaused` and `whenPaused`, which can be applied to
 * the functions of your contract. Note that they will not be pausable by
 * simply including this module, only once the modifiers are put in place.
 */
contract Pausable is Context {
	/**
	 * @dev Emitted when the pause is triggered by `account`.
	 */
	event Paused(address account);

	/**
	 * @dev Emitted when the pause is lifted by `account`.
	 */
	event Unpaused(address account);

	bool private _paused;

	/**
	 * @dev Initializes the contract in unpaused state.
	 */
	constructor () {
		_paused = false;
	}

	/**
	 * @dev Returns true if the contract is paused, and false otherwise.
	 */
	function paused() public view returns (bool) {
		return _paused;
	}

	/**
	 * @dev Modifier to make a function callable only when the contract is not paused.
	 *
	 * Requirements:
	 *
	 * - The contract must not be paused.
	 */
	modifier whenNotPaused() {
		require(!_paused, "Pausable: paused");
		_;
	}

	/**
	 * @dev Modifier to make a function callable only when the contract is paused.
	 *
	 * Requirements:
	 *
	 * - The contract must be paused.
	 */
	modifier whenPaused() {
		require(_paused, "Pausable: not paused");
		_;
	}

	/**
	 * @dev Triggers stopped state.
	 *
	 * Requirements:
	 *
	 * - The contract must not be paused.
	 */
	function _pause() internal virtual whenNotPaused {
		_paused = true;
		emit Paused(_msgSender());
	}

	/**
	 * @dev Returns to normal state.
	 *
	 * Requirements:
	 *
	 * - The contract must be paused.
	 */
	function _unpause() internal virtual whenPaused {
		_paused = false;
		emit Unpaused(_msgSender());
	}
}

// File: @openzeppelin\contracts\utils\ReentrancyGuard.sol

/**
 * @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].
 */
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 () {
		_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;
	}
}

// File: node_modules\@openzeppelin\contracts\utils\Address.sol

/**
 * @dev Collection of functions related to the address type
 */
library Address {
	/**
	 * @dev Returns true if `account` is a contract.
	 *
	 * [IMPORTANT]
	 * ====
	 * It is unsafe to assume that an address for which this function returns
	 * false is an externally-owned account (EOA) and not a contract.
	 *
	 * Among others, `isContract` will return false for the following
	 * types of addresses:
	 *
	 *  - an externally-owned account
	 *  - a contract in construction
	 *  - an address where a contract will be created
	 *  - an address where a contract lived, but was destroyed
	 * ====
	 */
	function isContract(address account) internal view returns (bool) {
		// According to EIP-1052, 0x0 is the value returned for not-yet created accounts
		// and 0xc5d2460186f7233c927e7db2dcc703c0e500b653ca82273b7bfad8045d85a470 is returned
		// for accounts without code, i.e. `keccak256('')`
		bytes32 codehash;
		bytes32 accountHash = 0xc5d2460186f7233c927e7db2dcc703c0e500b653ca82273b7bfad8045d85a470;
		// solhint-disable-next-line no-inline-assembly
		assembly { codehash := extcodehash(account) }
		return (codehash != accountHash && codehash != 0x0);
	}

	/**
	 * @dev Replacement for Solidity's `transfer`: sends `amount` wei to
	 * `recipient`, forwarding all available gas and reverting on errors.
	 *
	 * https://eips.ethereum.org/EIPS/eip-1884[EIP1884] increases the gas cost
	 * of certain opcodes, possibly making contracts go over the 2300 gas limit
	 * imposed by `transfer`, making them unable to receive funds via
	 * `transfer`. {sendValue} removes this limitation.
	 *
	 * https://diligence.consensys.net/posts/2019/09/stop-using-soliditys-transfer-now/[Learn more].
	 *
	 * IMPORTANT: because control is transferred to `recipient`, care must be
	 * taken to not create reentrancy vulnerabilities. Consider using
	 * {ReentrancyGuard} or the
	 * https://solidity.readthedocs.io/en/v0.5.11/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].
	 */
	function sendValue(address payable recipient, uint256 amount) internal {
		require(address(this).balance >= amount, "Address: insufficient balance");

		// solhint-disable-next-line avoid-low-level-calls, avoid-call-value
		(bool success, ) = recipient.call{ value: amount }("");
		require(success, "Address: unable to send value, recipient may have reverted");
	}

	/**
	 * @dev Performs a Solidity function call using a low level `call`. A
	 * plain`call` is an unsafe replacement for a function call: use this
	 * function instead.
	 *
	 * If `target` reverts with a revert reason, it is bubbled up by this
	 * function (like regular Solidity function calls).
	 *
	 * Returns the raw returned data. To convert to the expected return value,
	 * use https://solidity.readthedocs.io/en/latest/units-and-global-variables.html?highlight=abi.decode#abi-encoding-and-decoding-functions[`abi.decode`].
	 *
	 * Requirements:
	 *
	 * - `target` must be a contract.
	 * - calling `target` with `data` must not revert.
	 *
	 * _Available since v3.1._
	 */
	function functionCall(address target, bytes memory data) internal returns (bytes memory) {
	  return functionCall(target, data, "Address: low-level call failed");
	}

	/**
	 * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`], but with
	 * `errorMessage` as a fallback revert reason when `target` reverts.
	 *
	 * _Available since v3.1._
	 */
	function functionCall(address target, bytes memory data, string memory errorMessage) internal returns (bytes memory) {
		return _functionCallWithValue(target, data, 0, errorMessage);
	}

	/**
	 * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
	 * but also transferring `value` wei to `target`.
	 *
	 * Requirements:
	 *
	 * - the calling contract must have an ETH balance of at least `value`.
	 * - the called Solidity function must be `payable`.
	 *
	 * _Available since v3.1._
	 */
	function functionCallWithValue(address target, bytes memory data, uint256 value) internal returns (bytes memory) {
		return functionCallWithValue(target, data, value, "Address: low-level call with value failed");
	}

	/**
	 * @dev Same as {xref-Address-functionCallWithValue-address-bytes-uint256-}[`functionCallWithValue`], but
	 * with `errorMessage` as a fallback revert reason when `target` reverts.
	 *
	 * _Available since v3.1._
	 */
	function functionCallWithValue(address target, bytes memory data, uint256 value, string memory errorMessage) internal returns (bytes memory) {
		require(address(this).balance >= value, "Address: insufficient balance for call");
		return _functionCallWithValue(target, data, value, errorMessage);
	}

	function _functionCallWithValue(address target, bytes memory data, uint256 weiValue, string memory errorMessage) private returns (bytes memory) {
		require(isContract(target), "Address: call to non-contract");

		// solhint-disable-next-line avoid-low-level-calls
		(bool success, bytes memory returndata) = target.call{ value: weiValue }(data);
		if (success) {
			return returndata;
		} else {
			// Look for revert reason and bubble it up if present
			if (returndata.length > 0) {
				// The easiest way to bubble the revert reason is using memory via assembly

				// solhint-disable-next-line no-inline-assembly
				assembly {
					let returndata_size := mload(returndata)
					revert(add(32, returndata), returndata_size)
				}
			} else {
				revert(errorMessage);
			}
		}
	}
}

// File: @openzeppelin\contracts\token\ERC20\SafeERC20.sol

/**
 * @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");
		}
	}
}

// File: contracts\StakedRewardsPool.sol

abstract contract StakedRewardsPool is
	Context,
	ReentrancyGuard,
	Ownable,
	Pausable,
	IStakedRewardsPool
{
	using SafeERC20 for IERC20;
	using SafeMath for uint256;

	/* Mutable Internal State */

	mapping(address => uint256) internal _rewards;

	/* Immutable Private State */

	uint8 private _stakingTokenDecimals;
	IERC20 private _rewardsToken;
	IERC20 private _stakingToken;
	uint256 private _stakingTokenBase;

	/* Mutable Private State */

	mapping(address => uint256) private _balances;
	uint256 private _totalSupply;

	/* Constructor */

	constructor(
		IERC20 rewardsToken,
		IERC20 stakingToken,
		uint8 stakingTokenDecimals
	) Ownable() {
		// Prevent overflow, though 76 would create a safe but unusable contract
		require(
			stakingTokenDecimals < 77,
			"StakedRewardsPool: staking token has far too many decimals"
		);

		_rewardsToken = rewardsToken;

		_stakingToken = stakingToken;
		_stakingTokenDecimals = stakingTokenDecimals;
		_stakingTokenBase = 10**stakingTokenDecimals;
	}

	/* Public Views */

	function balanceOf(address account) public view override returns (uint256) {
		return _balances[account];
	}

	function earned(address account)
		public
		view
		virtual
		override
		returns (uint256);

	function rewardsToken() public view override returns (IERC20) {
		return _rewardsToken;
	}

	function stakingToken() public view override returns (IERC20) {
		return _stakingToken;
	}

	function stakingTokenDecimals() public view override returns (uint8) {
		return _stakingTokenDecimals;
	}

	function totalSupply() public view override returns (uint256) {
		return _totalSupply;
	}

	/* Public Mutators */

	function exit() public override nonReentrant {
		_exit();
	}

	function getReward() public override nonReentrant {
		_getReward();
	}

	function getRewardExact(uint256 amount) public override nonReentrant {
		_getRewardExact(amount);
	}

	function pause() public override onlyOwner {
		_pause();
	}

	// In the unlikely event that unsupported tokens are successfully sent to the
	// contract. This will also allow for removal of airdropped tokens.
	function recoverUnsupportedERC20(
		IERC20 token,
		address to,
		uint256 amount
	) public override onlyOwner {
		_recoverUnsupportedERC20(token, to, amount);
	}

	function stake(uint256 amount) public override nonReentrant whenNotPaused {
		_stakeFrom(_msgSender(), amount);
	}

	function unpause() public override onlyOwner {
		_unpause();
	}

	function updateReward() public override nonReentrant {
		_updateRewardFor(_msgSender());
	}

	function updateRewardFor(address account) public override nonReentrant {
		_updateRewardFor(account);
	}

	function withdraw(uint256 amount) public override nonReentrant {
		_withdraw(amount);
	}

	/* Internal Views */

	function _getStakingTokenBase() internal view returns (uint256) {
		return _stakingTokenBase;
	}

	/* Internal Mutators */

	function _exit() internal virtual {
		_withdraw(_balances[_msgSender()]);
		_getReward();
	}

	function _getReward() internal virtual {
		_updateRewardFor(_msgSender());
		uint256 reward = _rewards[_msgSender()];
		if (reward > 0) {
			_rewards[_msgSender()] = 0;
			_rewardsToken.safeTransfer(_msgSender(), reward);
			emit RewardPaid(_msgSender(), reward);
		}
	}

	function _getRewardExact(uint256 amount) internal virtual {
		_updateRewardFor(_msgSender());
		uint256 reward = _rewards[_msgSender()];
		require(
			amount <= reward,
			"StakedRewardsPool: can not redeem more rewards than you have earned"
		);
		_rewards[_msgSender()] = reward.sub(amount);
		_rewardsToken.safeTransfer(_msgSender(), amount);
		emit RewardPaid(_msgSender(), amount);
	}

	function _recoverUnsupportedERC20(
		IERC20 token,
		address to,
		uint256 amount
	) internal virtual {
		require(
			token != _stakingToken,
			"StakedRewardsPool: cannot withdraw the staking token"
		);
		require(
			token != _rewardsToken,
			"StakedRewardsPool: cannot withdraw the rewards token"
		);
		token.safeTransfer(to, amount);
		emit Recovered(token, to, amount);
	}

	function _stakeFrom(address account, uint256 amount) internal virtual {
		require(
			account != address(0),
			"StakedRewardsPool: cannot stake from the zero address"
		);
		require(amount > 0, "StakedRewardsPool: cannot stake zero");
		_updateRewardFor(account);
		_totalSupply = _totalSupply.add(amount);
		_balances[account] = _balances[account].add(amount);
		_stakingToken.safeTransferFrom(account, address(this), amount);
		emit Staked(account, amount);
	}

	function _updateRewardFor(address account) internal virtual;

	function _withdraw(uint256 amount) internal virtual {
		require(amount > 0, "StakedRewardsPool: cannot withdraw zero");
		_updateRewardFor(_msgSender());
		_totalSupply = _totalSupply.sub(amount);
		_balances[_msgSender()] = _balances[_msgSender()].sub(amount);
		_stakingToken.safeTransfer(_msgSender(), amount);
		emit Withdrawn(_msgSender(), amount);
	}
}

// File: contracts\StakedRewardsPoolTimedRate.sol

// Accuracy in block.timestamps is not needed.
// https://consensys.github.io/smart-contract-best-practices/recommendations/#the-15-second-rule
/* solhint-disable not-rely-on-time */

contract StakedRewardsPoolTimedRate is
	StakedRewardsPool,
	IStakedRewardsPoolTimedRate
{
	using SafeMath for uint256;

	/* Mutable Private State */

	uint256 private _accruedRewardPerToken;
	mapping(address => uint256) private _accruedRewardPerTokenPaid;
	uint256 private _lastUpdateTime;
	uint256 private _periodEndTime;
	uint256 private _periodStartTime;
	uint256 private _rewardRate;

	/* Modifiers */

	modifier whenStarted {
		require(
			hasStarted(),
			"StakedRewardsPoolTimedRate: current rewards distribution period has not yet begun"
		);
		_;
	}

	/* Constructor */

	constructor(
		IERC20 rewardsToken,
		IERC20 stakingToken,
		uint8 stakingTokenDecimals,
		uint256 periodStartTime,
		uint256 periodEndTime
	) StakedRewardsPool(rewardsToken, stakingToken, stakingTokenDecimals) {
		_periodStartTime = periodStartTime;
		_periodEndTime = periodEndTime;
	}

	/* Public Views */

	// Represents the ratio of reward token to staking token accrued thus far,
	// multiplied by 10**stakingTokenDecimal in case of a fraction.
	function accruedRewardPerToken() public view override returns (uint256) {
		uint256 totalSupply = totalSupply();
		if (totalSupply == 0) {
			return _accruedRewardPerToken;
		}

		uint256 lastUpdateTime = _lastUpdateTime;
		uint256 lastTimeApplicable = lastTimeRewardApplicable();

		// Allow staking at any time without earning undue rewards
		// The following is guaranteed if the next `if` is true:
		// lastUpdateTime == previous _periodEndTime || lastUpdateTime == 0
		if (_periodStartTime > lastUpdateTime) {
			// Prevent underflow
			if (_periodStartTime > lastTimeApplicable) {
				return _accruedRewardPerToken;
			}
			lastUpdateTime = _periodStartTime;
		}

		uint256 dt = lastTimeApplicable.sub(lastUpdateTime);
		if (dt == 0) {
			return _accruedRewardPerToken;
		}

		uint256 accruedReward = _rewardRate.mul(dt);

		return
			_accruedRewardPerToken.add(
				accruedReward.mul(_getStakingTokenBase()).div(totalSupply)
			);
	}

	function earned(address account)
		public
		view
		override(IStakedRewardsPool, StakedRewardsPool)
		returns (uint256)
	{
		// Divide by stakingTokenBase in accordance with accruedRewardPerToken()
		return
			balanceOf(account)
				.mul(accruedRewardPerToken().sub(_accruedRewardPerTokenPaid[account]))
				.div(_getStakingTokenBase())
				.add(_rewards[account]);
	}

	function hasStarted() public view override returns (bool) {
		return block.timestamp >= _periodStartTime;
	}

	function hasEnded() public view override returns (bool) {
		return block.timestamp >= _periodEndTime;
	}

	function lastTimeRewardApplicable() public view override returns (uint256) {
		// Returns 0 if we have never run a staking period.
		// Returns _periodEndTime if we have but we're not in a staking period.
		if (!hasStarted()) {
			return _lastUpdateTime;
		}
		return Math.min(block.timestamp, _periodEndTime);
	}

	function periodDuration() public view override returns (uint256) {
		return _periodEndTime.sub(_periodStartTime);
	}

	function periodEndTime() public view override returns (uint256) {
		return _periodEndTime;
	}

	function periodStartTime() public view override returns (uint256) {
		return _periodStartTime;
	}

	function rewardRate() public view override returns (uint256) {
		return _rewardRate;
	}

	function timeRemainingInPeriod()
		public
		view
		override
		whenStarted
		returns (uint256)
	{
		if (hasEnded()) {
			return 0;
		}
		return _periodEndTime.sub(block.timestamp);
	}

	/* Public Mutators */

	function addToRewardsAllocation(uint256 amount)
		public
		override
		nonReentrant
		onlyOwner
	{
		_addToRewardsAllocation(amount);
	}

	function setNewPeriod(uint256 startTime, uint256 endTime)
		public
		override
		onlyOwner
	{
		require(
			!hasStarted() || hasEnded(),
			"StakedRewardsPoolTimedRate: cannot change an ongoing staking period"
		);
		require(
			endTime > startTime,
			"StakedRewardsPoolTimedRate: endTime must be greater than startTime"
		);
		// The lastTimeRewardApplicable() function would not allow rewards for a
		// past period that was never started.
		require(
			startTime > block.timestamp,
			"StakedRewardsPoolTimedRate: startTime must be greater than the current block time"
		);
		// Ensure that rewards are fully granted before changing the period.
		_updateAccrual();

		if (hasEnded()) {
			// Reset reward rate if this a brand new period (not changing one)
			// Note that you MUST addToRewardsAllocation again if you forgot to call
			// this after the previous period ended but before adding rewards.
			_rewardRate = 0;
		} else {
			// Update reward rate for new duration
			uint256 totalReward = _rewardRate.mul(periodDuration());
			_rewardRate = totalReward.div(endTime.sub(startTime));
		}

		_periodStartTime = startTime;
		_periodEndTime = endTime;

		emit NewPeriodSet(startTime, endTime);
	}

	/* Internal Mutators */

	// Ensure that the amount param is equal to the amount you've added to the contract, otherwise the funds will run out before _periodEndTime.
	// If called during an ongoing staking period, the amount will be allocated
	// to the current staking period.
	// If called before or after a staking period, the amount will only be
	// applied to the next staking period.
	function _addToRewardsAllocation(uint256 amount) internal {
		// TODO Require that amount <= available rewards.
		_updateAccrual();

		// Update reward rate based on remaining time
		uint256 remainingTime;
		if (!hasStarted() || hasEnded()) {
			remainingTime = periodDuration();
		} else {
			remainingTime = timeRemainingInPeriod();
		}

		_rewardRate = _rewardRate.add(amount.div(remainingTime));

		emit RewardAdded(amount);
	}

	function _updateAccrual() internal {
		_accruedRewardPerToken = accruedRewardPerToken();
		_lastUpdateTime = lastTimeRewardApplicable();
	}

	// This logic is needed for any interaction that may manipulate rewards.
	function _updateRewardFor(address account) internal override {
		_updateAccrual();
		// Allocate due rewards.
		_rewards[account] = earned(account);
		// Remove ability to earn rewards on or before the current timestamp.
		_accruedRewardPerTokenPaid[account] = _accruedRewardPerToken;
	}
}