Contract Name:
CurryStatic
Contract Source Code:
File 1 of 1 : CurryStatic
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;
}
}
/*
* @dev Provides information about the current execution context, including the
* sender of the transaction and its data. While these are generally available
* via msg.sender and msg.data, they should not be accessed in such a direct
* manner, since when dealing with GSN meta-transactions the account sending and
* paying for execution may not be the actual sender (as far as an application
* is concerned).
*
* This contract is only required for intermediate, library-like contracts.
*/
abstract contract Context {
function _msgSender() internal view virtual returns (address payable) {
return msg.sender;
}
function _msgData() internal view virtual returns (bytes memory) {
this; // silence state mutability warning without generating bytecode - see https://github.com/ethereum/solidity/issues/2691
return msg.data;
}
}
/**
* @dev 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 virtual onlyOwner {
emit OwnershipTransferred(_owner, address(0));
_owner = address(0);
}
/**
* @dev Transfers ownership of the contract to a new account (`newOwner`).
* Can only be called by the current owner.
*/
function transferOwnership(address newOwner) public virtual onlyOwner {
require(newOwner != address(0), "Ownable: new owner is the zero address");
emit OwnershipTransferred(_owner, newOwner);
_owner = newOwner;
}
}
/**
* @dev 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);
}
contract CurryStatic is Ownable {
using SafeMath for uint256;
IERC20 public token;
struct Stake {
uint256 amount;
uint256 reward;
uint256 stakeIndex;
uint256 lastclaimedBlock;
uint256 fee;
uint256 rewardWithdrawn;
}
uint256 constant FEE_TO_STAKE = 1;
uint256 FEE_TO_UNSTAKE = 4;
address[] private stakingAddresses;
mapping(address => Stake) public addressToStakeMap;
mapping(uint256 => uint256) public cumulativeblockToReward;
uint256 public totalAmountForDistribution;
uint256 public totalStakes;
uint256 public lastRewardFromChefUpdatedBlock;
uint256 public totalNumberOfStakers;
address public teamAddress = address(0); // change address
address public chefAddress = address(0); // change address
constructor(IERC20 _token) public {
token = _token;
}
modifier onlyChef() {
require(chefAddress == _msgSender(), "CurryStatic: caller is not the chefaddress");
_;
}
// distribute function called by chef contract only
function distribute(uint256 amount) external onlyChef {
// update the total cumulative rewards where the tokens are sent from chef contract
totalAmountForDistribution = totalAmountForDistribution.add(amount);
lastRewardFromChefUpdatedBlock = block.number;
cumulativeblockToReward[lastRewardFromChefUpdatedBlock] = cumulativeblockToReward[lastRewardFromChefUpdatedBlock].add(totalAmountForDistribution);
}
// stake function
function stake(uint256 amount) public {
require(
amount != 0,
"amount cannot be zero"
);
Stake storage _stake = addressToStakeMap[_msgSender()];
if (_stake.amount == 0) {
_stake.stakeIndex = stakingAddresses.length;
stakingAddresses.push(_msgSender());
// update the lastrewardblock to keep track that , when he staked how much rewards came from chef contract
// only first time update, as multiple time stake applicable
_stake.lastclaimedBlock = lastRewardFromChefUpdatedBlock;
totalNumberOfStakers = totalNumberOfStakers.add(1);
}
uint256 fee = amount.mul(FEE_TO_STAKE).div(100); // 1% stake fee
uint256 amountAfterFee = amount.sub(fee); // actual staked amount
totalStakes = totalStakes.add(amountAfterFee); // update total stakes
_stake.amount = _stake.amount.add(amountAfterFee); // store the staking amount
// transfer tokens to this address
require(
token.transferFrom(_msgSender(), address(this), amountAfterFee),
"transferFrom failed."
);
// transfer the fee to teamaddress
require(
token.transferFrom(_msgSender(), teamAddress, fee),
"transfer failed"
);
}
// withdraw function
function withdraw() public {
Stake storage _stake = addressToStakeMap[_msgSender()];
if (_stake.amount == 0) {
revert("no amount to withdraw");
}
uint256 fee = _stake.amount.mul(FEE_TO_UNSTAKE).div(100); // 4% unstake fee
uint256 amountAfterFee = _stake.amount.sub(fee); // withdrawal amount
// Get the reward came from chef contract
// logic: last updated cumultaive reward - his staked time cumulative reward
_stake.reward = checkCurrentRewards(_msgSender());
// add the reward which got from chef contract via, distribute function calling from chef contract
uint256 withdrawlAmount = amountAfterFee.add(_stake.reward);
// delete the user and update stake
totalStakes = totalStakes.sub(_stake.amount); // update stake
totalNumberOfStakers = totalNumberOfStakers.sub(1);
delete addressToStakeMap[_msgSender()];
// transfer tokens to the user
require(
token.transfer(_msgSender(), withdrawlAmount),
"transfer failed"
);
// transfer the fee to teamaddress
require(
token.transfer(teamAddress, fee),
"transfer failed"
);
}
// update token address called by owner only
function changeTokenAddress(IERC20 newAddr) public onlyOwner {
require(
newAddr != IERC20(0),
"zero address is not allowed"
);
// token address can be changed when total stakers are 0
require(
totalNumberOfStakers == 0,
"stakers are present, can not change token address"
);
token = newAddr;
}
// update chef address called by owner only
function changeChefAddress(address newAddr) public onlyOwner {
require(
newAddr != address(0),
"zero address is not allowed"
);
chefAddress = newAddr;
}
// update team address called by owner only
function changeTeamAddress(address newAddr) public onlyOwner {
require(
newAddr != address(0),
"zero address is not allowed"
);
teamAddress = newAddr;
}
// withdraw tokens if no stakers are present
function withdrawUnClaimed() public onlyOwner {
require(
totalNumberOfStakers == 0,
"stakers are present, can not withdraw unclaimed"
);
require(
token.balanceOf(address(this)) != 0,
"totalAmountForDistribution is 0, can not claim"
);
require(
token.transfer(teamAddress, token.balanceOf(address(this))),
"transfer failed"
);
}
// check the current reward
function checkCurrentRewards(address user) public view returns (uint256) {
Stake storage _stake = addressToStakeMap[user];
// Get the reward came from chef contract
// logic: last updated cumultaive reward - his staked time cumulative reward
uint256 totalRewardInStakeperiod = cumulativeblockToReward[lastRewardFromChefUpdatedBlock].sub(cumulativeblockToReward[_stake.lastclaimedBlock]);
// calculate his reward according to his stake amount
uint256 currReward = totalRewardInStakeperiod.mul(_stake.amount).div(totalStakes);
return currReward;
}
// check staking amount
function checkStakingAmount(address user) public view returns (uint256) {
Stake storage _stake = addressToStakeMap[user];
return _stake.amount;
}
}