Contract Source Code:
File 1 of 1 : Pair
// File: contracts/libraries/UQ112x112.sol
pragma solidity >=0.8.0;
// a library for handling binary fixed point numbers (https://en.wikipedia.org/wiki/Q_(number_format))
// range: [0, 2**112 - 1]
// resolution: 1 / 2**112
library UQ112x112 {
uint224 constant Q112 = 2**112;
// encode a uint112 as a UQ112x112
function encode(uint112 y) internal pure returns (uint224 z) {
z = uint224(y) * Q112; // never overflows
}
// divide a UQ112x112 by a uint112, returning a UQ112x112
function uqdiv(uint224 x, uint112 y) internal pure returns (uint224 z) {
z = x / uint224(y);
}
}
// File: contracts/libraries/Math.sol
pragma solidity >=0.8.0;
// a library for performing various math operations
library Math {
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;
}
}
function add(uint256 x, uint256 y) internal pure returns (uint256 z) {
require((z = x + y) >= x, "ds-math-add-overflow");
}
function sub(uint256 x, uint256 y) internal pure returns (uint256 z) {
require((z = x - y) <= x, "ds-math-sub-underflow");
}
function mul(uint256 x, uint256 y) internal pure returns (uint256 z) {
require(y == 0 || (z = x * y) / y == x, "ds-math-mul-overflow");
}
}
// File: contracts/core/interfaces/IFactory.sol
pragma solidity >=0.8.0;
interface IFactory {
event PairCreated(
address indexed token0,
address indexed token1,
address pair,
uint256
);
event PairCreateLocked(
address indexed caller
);
event PairCreateUnlocked(
address indexed caller
);
event BootstrapSetted(
address indexed tokenA,
address indexed tokenB,
address indexed bootstrap
);
event FeetoUpdated(
address indexed feeto
);
event FeeBasePointUpdated(
uint8 basePoint
);
function feeto() external view returns (address);
function feeBasePoint() external view returns (uint8);
function lockForPairCreate() external view returns (bool);
function getPair(address tokenA, address tokenB)
external
view
returns (address pair);
function getBootstrap(address tokenA, address tokenB)
external
view
returns (address bootstrap);
function allPairs(uint256) external view returns (address pair);
function allPairsLength() external view returns (uint256);
function createPair(address tokenA, address tokenB)
external
returns (address pair);
}
// File: contracts/core/interfaces/IPair.sol
pragma solidity >=0.8.0;
interface IPair {
event Mint(address indexed sender, uint256 amount0, uint256 amount1);
event Burn(
address indexed sender,
uint256 amount0,
uint256 amount1,
address indexed to
);
event Swap(
address indexed sender,
uint256 amount0In,
uint256 amount1In,
uint256 amount0Out,
uint256 amount1Out,
address indexed to
);
event Sync(uint112 reserve0, uint112 reserve1);
function MINIMUM_LIQUIDITY() external pure returns (uint256);
function factory() external view returns (address);
function token0() external view returns (address);
function token1() external view returns (address);
function getReserves()
external
view
returns (uint112 reserve0, uint112 reserve1);
function mint(address to) external returns (uint256 liquidity);
function burn(address to)
external
returns (uint256 amount0, uint256 amount1);
function swap(
uint256 amount0Out,
uint256 amount1Out,
address to
) external;
function initialize(address, address) external;
}
// File: @openzeppelin/contracts/utils/Context.sol
pragma solidity ^0.8.0;
/*
* @dev Provides information about the current execution context, including the
* sender of the transaction and its data. While these are generally available
* via msg.sender and msg.data, they should not be accessed in such a direct
* manner, since when dealing with 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) {
return msg.sender;
}
function _msgData() internal view virtual returns (bytes calldata) {
return msg.data;
}
}
// File: @openzeppelin/contracts/token/ERC20/IERC20.sol
pragma solidity ^0.8.0;
/**
* @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: @openzeppelin/contracts/token/ERC20/extensions/IERC20Metadata.sol
pragma solidity ^0.8.0;
/**
* @dev Interface for the optional metadata functions from the ERC20 standard.
*
* _Available since v4.1._
*/
interface IERC20Metadata is IERC20 {
/**
* @dev Returns the name of the token.
*/
function name() external view returns (string memory);
/**
* @dev Returns the symbol of the token.
*/
function symbol() external view returns (string memory);
/**
* @dev Returns the decimals places of the token.
*/
function decimals() external view returns (uint8);
}
// File: @openzeppelin/contracts/token/ERC20/ERC20.sol
pragma solidity ^0.8.0;
/**
* @dev Implementation of the {IERC20} 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 {ERC20PresetMinterPauser}.
*
* TIP: For a detailed writeup see our guide
* https://forum.zeppelin.solutions/t/how-to-implement-erc20-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 ERC20 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 {IERC20-approve}.
*/
contract ERC20 is Context, IERC20, IERC20Metadata {
mapping(address => uint256) private _balances;
mapping(address => mapping(address => uint256)) private _allowances;
uint256 private _totalSupply;
string private _name;
string private _symbol;
/**
* @dev Sets the values for {name} and {symbol}.
*
* The default value of {decimals} is 18. To select a different value for
* {decimals} you should overload it.
*
* All two of these values are immutable: they can only be set once during
* construction.
*/
constructor(string memory name_, string memory symbol_) {
_name = name_;
_symbol = symbol_;
}
/**
* @dev Returns the name of the token.
*/
function name() public view virtual override returns (string memory) {
return _name;
}
/**
* @dev Returns the symbol of the token, usually a shorter version of the
* name.
*/
function symbol() public view virtual override returns (string memory) {
return _symbol;
}
/**
* @dev Returns the number of decimals used to get its user representation.
* For example, if `decimals` equals `2`, a balance of `505` tokens should
* be displayed to a user as `5,05` (`505 / 10 ** 2`).
*
* Tokens usually opt for a value of 18, imitating the relationship between
* Ether and Wei. This is the value {ERC20} uses, unless this function is
* overridden;
*
* NOTE: This information is only used for _display_ purposes: it in
* no way affects any of the arithmetic of the contract, including
* {IERC20-balanceOf} and {IERC20-transfer}.
*/
function decimals() public view virtual override returns (uint8) {
return 18;
}
/**
* @dev See {IERC20-totalSupply}.
*/
function totalSupply() public view virtual override returns (uint256) {
return _totalSupply;
}
/**
* @dev See {IERC20-balanceOf}.
*/
function balanceOf(address account) public view virtual override returns (uint256) {
return _balances[account];
}
/**
* @dev See {IERC20-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 virtual override returns (bool) {
_transfer(_msgSender(), recipient, amount);
return true;
}
/**
* @dev See {IERC20-allowance}.
*/
function allowance(address owner, address spender) public view virtual override returns (uint256) {
return _allowances[owner][spender];
}
/**
* @dev See {IERC20-approve}.
*
* Requirements:
*
* - `spender` cannot be the zero address.
*/
function approve(address spender, uint256 amount) public virtual override returns (bool) {
_approve(_msgSender(), spender, amount);
return true;
}
/**
* @dev See {IERC20-transferFrom}.
*
* Emits an {Approval} event indicating the updated allowance. This is not
* required by the EIP. See the note at the beginning of {ERC20}.
*
* Requirements:
*
* - `sender` and `recipient` cannot be the zero address.
* - `sender` must have a balance of at least `amount`.
* - the caller must have allowance for ``sender``'s tokens of at least
* `amount`.
*/
function transferFrom(
address sender,
address recipient,
uint256 amount
) public virtual override returns (bool) {
_transfer(sender, recipient, amount);
uint256 currentAllowance = _allowances[sender][_msgSender()];
require(currentAllowance >= amount, "ERC20: transfer amount exceeds allowance");
unchecked {
_approve(sender, _msgSender(), currentAllowance - amount);
}
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 {IERC20-approve}.
*
* Emits an {Approval} event indicating the updated allowance.
*
* Requirements:
*
* - `spender` cannot be the zero address.
*/
function increaseAllowance(address spender, uint256 addedValue) public virtual returns (bool) {
_approve(_msgSender(), spender, _allowances[_msgSender()][spender] + 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 {IERC20-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 virtual returns (bool) {
uint256 currentAllowance = _allowances[_msgSender()][spender];
require(currentAllowance >= subtractedValue, "ERC20: decreased allowance below zero");
unchecked {
_approve(_msgSender(), spender, currentAllowance - subtractedValue);
}
return true;
}
/**
* @dev Moves `amount` of tokens from `sender` to `recipient`.
*
* This internal function is equivalent to {transfer}, and can be used to
* e.g. implement automatic token fees, slashing mechanisms, etc.
*
* Emits a {Transfer} event.
*
* Requirements:
*
* - `sender` cannot be the zero address.
* - `recipient` cannot be the zero address.
* - `sender` must have a balance of at least `amount`.
*/
function _transfer(
address sender,
address recipient,
uint256 amount
) internal virtual {
require(sender != address(0), "ERC20: transfer from the zero address");
require(recipient != address(0), "ERC20: transfer to the zero address");
_beforeTokenTransfer(sender, recipient, amount);
uint256 senderBalance = _balances[sender];
require(senderBalance >= amount, "ERC20: transfer amount exceeds balance");
unchecked {
_balances[sender] = senderBalance - amount;
}
_balances[recipient] += amount;
emit Transfer(sender, recipient, amount);
_afterTokenTransfer(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:
*
* - `account` cannot be the zero address.
*/
function _mint(address account, uint256 amount) internal virtual {
require(account != address(0), "ERC20: mint to the zero address");
_beforeTokenTransfer(address(0), account, amount);
_totalSupply += amount;
_balances[account] += amount;
emit Transfer(address(0), account, amount);
_afterTokenTransfer(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 virtual {
require(account != address(0), "ERC20: burn from the zero address");
_beforeTokenTransfer(account, address(0), amount);
uint256 accountBalance = _balances[account];
require(accountBalance >= amount, "ERC20: burn amount exceeds balance");
unchecked {
_balances[account] = accountBalance - amount;
}
_totalSupply -= amount;
emit Transfer(account, address(0), amount);
_afterTokenTransfer(account, address(0), amount);
}
/**
* @dev Sets `amount` as the allowance of `spender` over the `owner` s tokens.
*
* This 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 virtual {
require(owner != address(0), "ERC20: approve from the zero address");
require(spender != address(0), "ERC20: approve to the zero address");
_allowances[owner][spender] = amount;
emit Approval(owner, spender, amount);
}
/**
* @dev Hook that is called before any transfer of tokens. This includes
* minting and burning.
*
* Calling conditions:
*
* - when `from` and `to` are both non-zero, `amount` of ``from``'s tokens
* will be transferred to `to`.
* - when `from` is zero, `amount` tokens will be minted for `to`.
* - when `to` is zero, `amount` of ``from``'s tokens will be burned.
* - `from` and `to` are never both zero.
*
* To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].
*/
function _beforeTokenTransfer(
address from,
address to,
uint256 amount
) internal virtual {}
/**
* @dev Hook that is called after any transfer of tokens. This includes
* minting and burning.
*
* Calling conditions:
*
* - when `from` and `to` are both non-zero, `amount` of ``from``'s tokens
* has been transferred to `to`.
* - when `from` is zero, `amount` tokens have been minted for `to`.
* - when `to` is zero, `amount` of ``from``'s tokens have been burned.
* - `from` and `to` are never both zero.
*
* To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].
*/
function _afterTokenTransfer(
address from,
address to,
uint256 amount
) internal virtual {}
}
// File: contracts/core/Pair.sol
pragma solidity >=0.8.0;
contract Pair is IPair, ERC20 {
using Math for uint256;
uint256 public constant override MINIMUM_LIQUIDITY = 10**3;
bytes4 private constant SELECTOR =
bytes4(keccak256(bytes("transfer(address,uint256)")));
address public override factory;
address public override token0;
address public override token1;
uint112 private reserve0;
uint112 private reserve1;
uint256 public kLast;
uint8 private unlocked = 1;
modifier lock() {
require(unlocked == 1, "LOCKED");
unlocked = 0;
_;
unlocked = 1;
}
function _safeTransfer(
address token,
address to,
uint256 value
) private {
(bool success, bytes memory data) = token.call(
abi.encodeWithSelector(SELECTOR, to, value)
);
require(
success && (data.length == 0 || abi.decode(data, (bool))),
"TRANSFER_FAILED"
);
}
function getReserves()
public
view
override
returns (uint112 _reserve0, uint112 _reserve1)
{
_reserve0 = reserve0;
_reserve1 = reserve1;
}
constructor() ERC20("Zenlink LP Token", "ZLK-LP") {
factory = msg.sender;
}
function initialize(address _token0, address _token1) external override {
require(msg.sender == factory, "Only called by factory");
token0 = _token0;
token1 = _token1;
}
function _mintFee(uint112 _reserve0, uint112 _reserve1)
private
returns (uint8 feeBasePoint)
{
address feeTo = IFactory(factory).feeto();
feeBasePoint = IFactory(factory).feeBasePoint();
uint256 _kLast = kLast; // gas savings
if (feeBasePoint > 0) {
if (_kLast != 0) {
uint256 rootK = Math.sqrt(
uint256(_reserve0).mul(uint256(_reserve1))
);
uint256 rootKLast = Math.sqrt(_kLast);
if (rootK > rootKLast) {
uint256 numerator = totalSupply().mul(rootK.sub(rootKLast));
uint256 denominator = (rootK.mul(30 - feeBasePoint) /
feeBasePoint).add(rootKLast);
uint256 liquidity = numerator / denominator;
if (liquidity > 0) _mint(feeTo, liquidity);
}
}
} else if (_kLast != 0) {
kLast = 0;
}
}
function mint(address to)
external
override
lock
returns (uint256 liquidity)
{
(uint112 _reserve0, uint112 _reserve1) = getReserves();
uint256 balance0 = IERC20(token0).balanceOf(address(this));
uint256 balance1 = IERC20(token1).balanceOf(address(this));
uint256 amount0 = balance0.sub(_reserve0);
uint256 amount1 = balance1.sub(_reserve1);
uint8 feeBasePoint = _mintFee(_reserve0, _reserve1);
uint256 _totalSupply = totalSupply();
if (_totalSupply == 0) {
address feeTo = IFactory(factory).feeto();
liquidity = Math.sqrt(amount0.mul(amount1)).sub(MINIMUM_LIQUIDITY);
_mint(feeTo, MINIMUM_LIQUIDITY);
} else {
liquidity = Math.min(
amount0.mul(_totalSupply) / _reserve0,
amount1.mul(_totalSupply) / _reserve1
);
}
require(liquidity > 0, "INSUFFICIENT_LIQUIDITY_MINTED");
_mint(to, liquidity);
_update(balance0, balance1);
if (feeBasePoint > 0) kLast = uint256(reserve0).mul(reserve1);
emit Mint(msg.sender, amount0, amount1);
}
function burn(address to)
external
override
lock
returns (uint256 amount0, uint256 amount1)
{
(uint112 _reserve0, uint112 _reserve1) = getReserves();
address _token0 = token0;
address _token1 = token1;
uint256 balance0 = IERC20(_token0).balanceOf(address(this));
uint256 balance1 = IERC20(_token1).balanceOf(address(this));
uint256 liquidity = balanceOf(address(this));
uint8 feeBasePoint = _mintFee(_reserve0, _reserve1);
uint256 _totalSupply = totalSupply();
amount0 = liquidity.mul(balance0) / _totalSupply;
amount1 = liquidity.mul(balance1) / _totalSupply;
require(amount0 > 0 && amount1 > 0, "INSUFFICIENT_LIQUIDITY_BURNED");
_burn(address(this), liquidity);
_safeTransfer(_token0, to, amount0);
_safeTransfer(_token1, to, amount1);
balance0 = IERC20(_token0).balanceOf(address(this));
balance1 = IERC20(_token1).balanceOf(address(this));
_update(balance0, balance1);
if (feeBasePoint > 0) kLast = uint256(reserve0).mul(reserve1);
emit Burn(msg.sender, amount0, amount1, to);
}
function swap(
uint256 amount0Out,
uint256 amount1Out,
address to
) external override lock {
require(amount0Out > 0 || amount1Out > 0, "INSUFFICIENT_OUTPUT_AMOUNT");
(uint112 _reserve0, uint112 _reserve1) = getReserves();
require(
amount0Out < _reserve0 && amount1Out < _reserve1,
"INSUFFICIENT_LIQUIDITY"
);
uint256 balance0;
uint256 balance1;
{
address _token0 = token0;
address _token1 = token1;
require(to != _token0 && to != _token1, "INVALID_TO");
if (amount0Out > 0) _safeTransfer(_token0, to, amount0Out);
if (amount1Out > 0) _safeTransfer(_token1, to, amount1Out);
balance0 = IERC20(_token0).balanceOf(address(this));
balance1 = IERC20(_token1).balanceOf(address(this));
}
uint256 amount0In = balance0 > _reserve0 - amount0Out
? balance0 - (_reserve0 - amount0Out)
: 0;
uint256 amount1In = balance1 > _reserve1 - amount1Out
? balance1 - (_reserve1 - amount1Out)
: 0;
require(amount0In > 0 || amount1In > 0, " INSUFFICIENT_INPUT_AMOUNT");
{
uint256 balance0Adjusted = balance0.mul(1000).sub(amount0In.mul(3));
uint256 balance1Adjusted = balance1.mul(1000).sub(amount1In.mul(3));
require(
balance0Adjusted.mul(balance1Adjusted) >=
uint256(_reserve0).mul(_reserve1).mul(1000**2),
"Pair: K"
);
}
_update(balance0, balance1);
emit Swap(msg.sender, amount0In, amount1In, amount0Out, amount1Out, to);
}
function _update(uint256 balance0, uint256 balance1) private {
require(
balance0 <= type(uint112).max && balance1 <= type(uint112).max,
"OVERFLOW"
);
reserve0 = uint112(balance0);
reserve1 = uint112(balance1);
emit Sync(reserve0, reserve1);
}
}