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Created 3 years agoDiff never expires

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/**

*Submitted for verification at BscScan.com on 2021-04-23

/**

*Submitted for verification at BscScan.com on 2021-04-22

/**

*Submitted for verification at BscScan.com on 2021-04-22

/**

*Submitted for verification at BscScan.com on 2020-09-19

pragma solidity =0.5.16;

interface IPancakeFactory {

interface IPalmFactory {

event PairCreated(address indexed token0, address indexed token1, address pair, uint);

function feeTo() external view returns (address);

function burnFeeTo() external view returns (address);

function feeToSetter() external view returns (address);

function getPair(address tokenA, address tokenB) external view returns (address pair);

function allPairs(uint) external view returns (address pair);

function allPairsLength() external view returns (uint);

function createPair(address tokenA, address tokenB) external returns (address pair);

function setFeeTo(address) external;

function setBurnFeeTo(address) external;

function setFeeToSetter(address) external;

}

interface IPancakePair {

interface IPalmPair {

event Approval(address indexed owner, address indexed spender, uint value);

event Transfer(address indexed from, address indexed to, uint value);

function name() external pure returns (string memory);

function symbol() external pure returns (string memory);

function decimals() external pure returns (uint8);

function totalSupply() external view returns (uint);

function balanceOf(address owner) external view returns (uint);

function allowance(address owner, address spender) external view returns (uint);

function approve(address spender, uint value) external returns (bool);

function transfer(address to, uint value) external returns (bool);

function transferFrom(address from, address to, uint value) external returns (bool);

function DOMAIN_SEPARATOR() external view returns (bytes32);

function PERMIT_TYPEHASH() external pure returns (bytes32);

function nonces(address owner) external view returns (uint);

function permit(address owner, address spender, uint value, uint deadline, uint8 v, bytes32 r, bytes32 s) external;

event Mint(address indexed sender, uint amount0, uint amount1);

event Burn(address indexed sender, uint amount0, uint amount1, address indexed to);

event Swap(

address indexed sender,

uint amount0In,

uint amount1In,

uint amount0Out,

uint amount1Out,

address indexed to

);

event Sync(uint112 reserve0, uint112 reserve1);

function MINIMUM_LIQUIDITY() external pure returns (uint);

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, uint32 blockTimestampLast);

function price0CumulativeLast() external view returns (uint);

function price1CumulativeLast() external view returns (uint);

function kLast() external view returns (uint);

function mint(address to) external returns (uint liquidity);

function burn(address to) external returns (uint amount0, uint amount1);

function swap(uint amount0Out, uint amount1Out, address to, bytes calldata data) external;

function skim(address to) external;

function sync() external;

function initialize(address, address) external;

}

interface IPancakeERC20 {

interface IPalmERC20 {

event Approval(address indexed owner, address indexed spender, uint value);

event Transfer(address indexed from, address indexed to, uint value);

function name() external pure returns (string memory);

function symbol() external pure returns (string memory);

function decimals() external pure returns (uint8);

function totalSupply() external view returns (uint);

function balanceOf(address owner) external view returns (uint);

function allowance(address owner, address spender) external view returns (uint);

function approve(address spender, uint value) external returns (bool);

function transfer(address to, uint value) external returns (bool);

function transferFrom(address from, address to, uint value) external returns (bool);

function DOMAIN_SEPARATOR() external view returns (bytes32);

function PERMIT_TYPEHASH() external pure returns (bytes32);

function nonces(address owner) external view returns (uint);

function permit(address owner, address spender, uint value, uint deadline, uint8 v, bytes32 r, bytes32 s) external;

}

// a library for performing overflow-safe math, courtesy of DappHub (https://github.com/dapphub/ds-math)

library SafeMath {

function add(uint x, uint y) internal pure returns (uint z) {

require((z = x + y) >= x, 'ds-math-add-overflow');

}

function sub(uint x, uint y) internal pure returns (uint z) {

require((z = x - y) <= x, 'ds-math-sub-underflow');

}

function mul(uint x, uint y) internal pure returns (uint z) {

require(y == 0 || (z = x * y) / y == x, 'ds-math-mul-overflow');

}

contract PancakeERC20 is IPancakeERC20 {

contract PalmERC20 is IPalmERC20 {

using SafeMath for uint;

string public constant name = 'Pancake LPs';

string public constant name = 'Palm LPs';

string public constant symbol = 'Cake-LP';

string public constant symbol = 'Palm-LP';

uint8 public constant decimals = 18;

uint public totalSupply;

mapping(address => uint) public balanceOf;

mapping(address => mapping(address => uint)) public allowance;

bytes32 public DOMAIN_SEPARATOR;

// keccak256("Permit(address owner,address spender,uint256 value,uint256 nonce,uint256 deadline)");

bytes32 public constant PERMIT_TYPEHASH = 0x6e71edae12b1b97f4d1f60370fef10105fa2faae0126114a169c64845d6126c9;

mapping(address => uint) public nonces;

event Approval(address indexed owner, address indexed spender, uint value);

event Transfer(address indexed from, address indexed to, uint value);

constructor() public {

uint chainId;

assembly {

chainId := chainid

}

DOMAIN_SEPARATOR = keccak256(

abi.encode(

keccak256('EIP712Domain(string name,string version,uint256 chainId,address verifyingContract)'),

keccak256(bytes(name)),

keccak256(bytes('1')),

chainId,

address(this)

)

);

}

function _mint(address to, uint value) internal {

totalSupply = totalSupply.add(value);

balanceOf[to] = balanceOf[to].add(value);

emit Transfer(address(0), to, value);

}

function _burn(address from, uint value) internal {

balanceOf[from] = balanceOf[from].sub(value);

totalSupply = totalSupply.sub(value);

emit Transfer(from, address(0), value);

}

function _approve(address owner, address spender, uint value) private {

allowance[owner][spender] = value;

emit Approval(owner, spender, value);

}

function _transfer(address from, address to, uint value) private {

balanceOf[from] = balanceOf[from].sub(value);

balanceOf[to] = balanceOf[to].add(value);

emit Transfer(from, to, value);

}

function approve(address spender, uint value) external returns (bool) {

_approve(msg.sender, spender, value);

return true;

}

function transfer(address to, uint value) external returns (bool) {

_transfer(msg.sender, to, value);

return true;

}

function transferFrom(address from, address to, uint value) external returns (bool) {

if (allowance[from][msg.sender] != uint(-1)) {

allowance[from][msg.sender] = allowance[from][msg.sender].sub(value);

}

_transfer(from, to, value);

return true;

}

function permit(address owner, address spender, uint value, uint deadline, uint8 v, bytes32 r, bytes32 s) external {

require(deadline >= block.timestamp, 'Pancake: EXPIRED');

require(deadline >= block.timestamp, 'Palm: EXPIRED');

bytes32 digest = keccak256(

abi.encodePacked(

'\x19\x01',

DOMAIN_SEPARATOR,

keccak256(abi.encode(PERMIT_TYPEHASH, owner, spender, value, nonces[owner]++, deadline))

)

);

address recoveredAddress = ecrecover(digest, v, r, s);

require(recoveredAddress != address(0) && recoveredAddress == owner, 'Pancake: INVALID_SIGNATURE');

require(recoveredAddress != address(0) && recoveredAddress == owner, 'Palm: INVALID_SIGNATURE');

_approve(owner, spender, value);

}

// a library for performing various math operations

library Math {

function min(uint x, uint y) internal pure returns (uint z) {

z = x < y ? x : y;

}

// babylonian method (https://en.wikipedia.org/wiki/Methods_of_computing_square_roots#Babylonian_method)

function sqrt(uint y) internal pure returns (uint z) {

if (y > 3) {

z = y;

uint x = y / 2 + 1;

while (x < z) {

z = x;

x = (y / x + x) / 2;

}

} else if (y != 0) {

z = 1;

}

// 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);

}

interface IERC20 {

event Approval(address indexed owner, address indexed spender, uint value);

event Transfer(address indexed from, address indexed to, uint value);

function name() external view returns (string memory);

function symbol() external view returns (string memory);

function decimals() external view returns (uint8);

function totalSupply() external view returns (uint);

function balanceOf(address owner) external view returns (uint);

function allowance(address owner, address spender) external view returns (uint);

function approve(address spender, uint value) external returns (bool);

function transfer(address to, uint value) external returns (bool);

function transferFrom(address from, address to, uint value) external returns (bool);

}

interface IPancakeCallee {

interface IPalmCallee {

function pancakeCall(address sender, uint amount0, uint amount1, bytes calldata data) external;

function PalmCall(address sender, uint amount0, uint amount1, bytes calldata data) external;

}

contract PancakePair is IPancakePair, PancakeERC20 {

contract PalmPair is IPalmPair, PalmERC20 {

using SafeMath for uint;

using UQ112x112 for uint224;

uint public constant MINIMUM_LIQUIDITY = 10**3;

bytes4 private constant SELECTOR = bytes4(keccak256(bytes('transfer(address,uint256)')));

address public factory;

address public token0;

address public token1;

uint112 private reserve0; // uses single storage slot, accessible via getReserves

uint112 private reserve1; // uses single storage slot, accessible via getReserves

uint32 private blockTimestampLast; // uses single storage slot, accessible via getReserves

uint public price0CumulativeLast;

uint public price1CumulativeLast;

uint public kLast; // reserve0 * reserve1, as of immediately after the most recent liquidity event

uint private unlocked = 1;

modifier lock() {

require(unlocked == 1, 'Pancake: LOCKED');

require(unlocked == 1, 'Palm: LOCKED');

unlocked = 0;

unlocked = 1;

}

function getReserves() public view returns (uint112 _reserve0, uint112 _reserve1, uint32 _blockTimestampLast) {

_reserve0 = reserve0;

_reserve1 = reserve1;

_blockTimestampLast = blockTimestampLast;

}

function _safeTransfer(address token, address to, uint value) private {

(bool success, bytes memory data) = token.call(abi.encodeWithSelector(SELECTOR, to, value));

require(success && (data.length == 0 || abi.decode(data, (bool))), 'Pancake: TRANSFER_FAILED');

require(success && (data.length == 0 || abi.decode(data, (bool))), 'Palm: TRANSFER_FAILED');

}

event Mint(address indexed sender, uint amount0, uint amount1);

event Burn(address indexed sender, uint amount0, uint amount1, address indexed to);

event Swap(

address indexed sender,

uint amount0In,

uint amount1In,

uint amount0Out,

uint amount1Out,

address indexed to

);

event Sync(uint112 reserve0, uint112 reserve1);

constructor() public {

factory = msg.sender;

}

// called once by the factory at time of deployment

function initialize(address _token0, address _token1) external {

require(msg.sender == factory, 'Pancake: FORBIDDEN'); // sufficient check

require(msg.sender == factory, 'Palm: FORBIDDEN'); // sufficient check

token0 = _token0;

token1 = _token1;

}

// update reserves and, on the first call per block, price accumulators

function _update(uint balance0, uint balance1, uint112 _reserve0, uint112 _reserve1) private {

require(balance0 <= uint112(-1) && balance1 <= uint112(-1), 'Pancake: OVERFLOW');

require(balance0 <= uint112(-1) && balance1 <= uint112(-1), 'Palm: OVERFLOW');

uint32 blockTimestamp = uint32(block.timestamp % 2**32);

uint32 timeElapsed = blockTimestamp - blockTimestampLast; // overflow is desired

if (timeElapsed > 0 && _reserve0 != 0 && _reserve1 != 0) {

// * never overflows, and + overflow is desired

price0CumulativeLast += uint(UQ112x112.encode(_reserve1).uqdiv(_reserve0)) * timeElapsed;

price1CumulativeLast += uint(UQ112x112.encode(_reserve0).uqdiv(_reserve1)) * timeElapsed;

}

reserve0 = uint112(balance0);

reserve1 = uint112(balance1);

blockTimestampLast = blockTimestamp;

emit Sync(reserve0, reserve1);

}

// if fee is on, mint liquidity equivalent to 8/25 of the growth in sqrt(k)

// if fee is on, mint liquidity equivalent to 20/25 of the growth in sqrt(k)

function _mintFee(uint112 _reserve0, uint112 _reserve1) private returns (bool feeOn) {

address feeTo = IPancakeFactory(factory).feeTo();

address feeTo = IPalmFactory(factory).feeTo();

feeOn = feeTo != address(0);

address burnFeeTo = IPalmFactory(factory).burnFeeTo();

feeOn = feeTo != address(0) && burnFeeTo != address(0);

uint _kLast = kLast; // gas savings

if (feeOn) {

if (_kLast != 0) {

uint rootK = Math.sqrt(uint(_reserve0).mul(_reserve1));

uint rootKLast = Math.sqrt(_kLast);

if (rootK > rootKLast) {

uint numerator = totalSupply.mul(rootK.sub(rootKLast)).mul(8);

uint numerator = totalSupply.mul(rootK.sub(rootKLast)).mul(22);

uint denominator = rootK.mul(17).add(rootKLast.mul(8));

uint liquidity = numerator / denominator;

if (liquidity > 0) _mint(feeTo, liquidity);

if (liquidity > 0) {

uint burnFee = ((liquidity.mul(75)) / 100);

liquidity = liquidity.sub(burnFee);

_mint(burnFeeTo, burnFee);

_mint(feeTo, liquidity);

}

} else if (_kLast != 0) {

kLast = 0;

}

// this low-level function should be called from a contract which performs important safety checks

function mint(address to) external lock returns (uint liquidity) {

(uint112 _reserve0, uint112 _reserve1,) = getReserves(); // gas savings

uint balance0 = IERC20(token0).balanceOf(address(this));

uint balance1 = IERC20(token1).balanceOf(address(this));

uint amount0 = balance0.sub(_reserve0);

uint amount1 = balance1.sub(_reserve1);

bool feeOn = _mintFee(_reserve0, _reserve1);

uint _totalSupply = totalSupply; // gas savings, must be defined here since totalSupply can update in _mintFee

if (_totalSupply == 0) {

liquidity = Math.sqrt(amount0.mul(amount1)).sub(MINIMUM_LIQUIDITY);

_mint(address(0), MINIMUM_LIQUIDITY); // permanently lock the first MINIMUM_LIQUIDITY tokens

} else {

liquidity = Math.min(amount0.mul(_totalSupply) / _reserve0, amount1.mul(_totalSupply) / _reserve1);

}

require(liquidity > 0, 'Pancake: INSUFFICIENT_LIQUIDITY_MINTED');

require(liquidity > 0, 'Palm: INSUFFICIENT_LIQUIDITY_MINTED');

_mint(to, liquidity);

_update(balance0, balance1, _reserve0, _reserve1);

if (feeOn) kLast = uint(reserve0).mul(reserve1); // reserve0 and reserve1 are up-to-date

emit Mint(msg.sender, amount0, amount1);

}

// this low-level function should be called from a contract which performs important safety checks

function burn(address to) external lock returns (uint amount0, uint amount1) {

(uint112 _reserve0, uint112 _reserve1,) = getReserves(); // gas savings

address _token0 = token0; // gas savings

address _token1 = token1; // gas savings

uint balance0 = IERC20(_token0).balanceOf(address(this));

uint balance1 = IERC20(_token1).balanceOf(address(this));

uint liquidity = balanceOf[address(this)];

bool feeOn = _mintFee(_reserve0, _reserve1);

uint _totalSupply = totalSupply; // gas savings, must be defined here since totalSupply can update in _mintFee

amount0 = liquidity.mul(balance0) / _totalSupply; // using balances ensures pro-rata distribution

amount1 = liquidity.mul(balance1) / _totalSupply; // using balances ensures pro-rata distribution

require(amount0 > 0 && amount1 > 0, 'Pancake: INSUFFICIENT_LIQUIDITY_BURNED');

require(amount0 > 0 && amount1 > 0, 'Palm: 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, _reserve0, _reserve1);

if (feeOn) kLast = uint(reserve0).mul(reserve1); // reserve0 and reserve1 are up-to-date

emit Burn(msg.sender, amount0, amount1, to);

}

// this low-level function should be called from a contract which performs important safety checks

function swap(uint amount0Out, uint amount1Out, address to, bytes calldata data) external lock {

require(amount0Out > 0 || amount1Out > 0, 'Pancake: INSUFFICIENT_OUTPUT_AMOUNT');

require(amount0Out > 0 || amount1Out > 0, 'Palm: INSUFFICIENT_OUTPUT_AMOUNT');

(uint112 _reserve0, uint112 _reserve1,) = getReserves(); // gas savings

require(amount0Out < _reserve0 && amount1Out < _reserve1, 'Pancake: INSUFFICIENT_LIQUIDITY');

require(amount0Out < _reserve0 && amount1Out < _reserve1, 'Palm: INSUFFICIENT_LIQUIDITY');

uint balance0;

uint balance1;

{ // scope for _token{0,1}, avoids stack too deep errors

address _token0 = token0;

address _token1 = token1;

require(to != _token0 && to != _token1, 'Pancake: INVALID_TO');

require(to != _token0 && to != _token1, 'Palm: INVALID_TO');

if (amount0Out > 0) _safeTransfer(_token0, to, amount0Out); // optimistically transfer tokens

if (amount1Out > 0) _safeTransfer(_token1, to, amount1Out); // optimistically transfer tokens

if (data.length > 0) IPancakeCallee(to).pancakeCall(msg.sender, amount0Out, amount1Out, data);

if (data.length > 0) IPalmCallee(to).PalmCall(msg.sender, amount0Out, amount1Out, data);

balance0 = IERC20(_token0).balanceOf(address(this));

balance1 = IERC20(_token1).balanceOf(address(this));

}

uint amount0In = balance0 > _reserve0 - amount0Out ? balance0 - (_reserve0 - amount0Out) : 0;

uint amount1In = balance1 > _reserve1 - amount1Out ? balance1 - (_reserve1 - amount1Out) : 0;

require(amount0In > 0 || amount1In > 0, 'Pancake: INSUFFICIENT_INPUT_AMOUNT');

require(amount0In > 0 || amount1In > 0, 'Palm: INSUFFICIENT_INPUT_AMOUNT');

{ // scope for reserve{0,1}Adjusted, avoids stack too deep errors

uint balance0Adjusted = (balance0.mul(10000).sub(amount0In.mul(25)));

uint balance1Adjusted = (balance1.mul(10000).sub(amount1In.mul(25)));

require(balance0Adjusted.mul(balance1Adjusted) >= uint(_reserve0).mul(_reserve1).mul(10000**2), 'Pancake: K');

require(balance0Adjusted.mul(balance1Adjusted) >= uint(_reserve0).mul(_reserve1).mul(10000**2), 'Palm: K');

}

_update(balance0, balance1, _reserve0, _reserve1);

emit Swap(msg.sender, amount0In, amount1In, amount0Out, amount1Out, to);

}

// force balances to match reserves

function skim(address to) external lock {

address _token0 = token0; // gas savings

address _token1 = token1; // gas savings

_safeTransfer(_token0, to, IERC20(_token0).balanceOf(address(this)).sub(reserve0));

_safeTransfer(_token1, to, IERC20(_token1).balanceOf(address(this)).sub(reserve1));

}

// force reserves to match balances

function sync() external lock {

_update(IERC20(token0).balanceOf(address(this)), IERC20(token1).balanceOf(address(this)), reserve0, reserve1);

}

contract PancakeFactory is IPancakeFactory {

contract PalmFactory is IPalmFactory {

bytes32 public constant INIT_CODE_PAIR_HASH = keccak256(abi.encodePacked(type(PancakePair).creationCode));

bytes32 public constant INIT_CODE_PAIR_HASH = keccak256(abi.encodePacked(type(PalmPair).creationCode));

address public feeTo;

address public burnFeeTo;

address public feeToSetter;

mapping(address => mapping(address => address)) public getPair;

address[] public allPairs;

event PairCreated(address indexed token0, address indexed token1, address pair, uint);

constructor(address _feeToSetter) public {

feeToSetter = _feeToSetter;

}

function allPairsLength() external view returns (uint) {

return allPairs.length;

}

function createPair(address tokenA, address tokenB) external returns (address pair) {

require(tokenA != tokenB, 'Pancake: IDENTICAL_ADDRESSES');

require(tokenA != tokenB, 'Palm: IDENTICAL_ADDRESSES');

(address token0, address token1) = tokenA < tokenB ? (tokenA, tokenB) : (tokenB, tokenA);

require(token0 != address(0), 'Pancake: ZERO_ADDRESS');

require(token0 != address(0), 'Palm: ZERO_ADDRESS');

require(getPair[token0][token1] == address(0), 'Pancake: PAIR_EXISTS'); // single check is sufficient

require(getPair[token0][token1] == address(0), 'Palm: PAIR_EXISTS'); // single check is sufficient

bytes memory bytecode = type(PancakePair).creationCode;

bytes memory bytecode = type(PalmPair).creationCode;

bytes32 salt = keccak256(abi.encodePacked(token0, token1));

assembly {

pair := create2(0, add(bytecode, 32), mload(bytecode), salt)

}

IPancakePair(pair).initialize(token0, token1);

IPalmPair(pair).initialize(token0, token1);

getPair[token0][token1] = pair;

getPair[token1][token0] = pair; // populate mapping in the reverse direction

allPairs.push(pair);

emit PairCreated(token0, token1, pair, allPairs.length);

}

function setFeeTo(address _feeTo) external {

require(msg.sender == feeToSetter, 'Pancake: FORBIDDEN');

require(msg.sender == feeToSetter, 'Palm: FORBIDDEN');

feeTo = _feeTo;

}

function setBurnFeeTo(address _burnFeeTo) external {

require(msg.sender == feeToSetter, 'Palm: FORBIDDEN');

burnFeeTo = _burnFeeTo;

}

function setFeeToSetter(address _feeToSetter) external {

require(msg.sender == feeToSetter, 'Pancake: FORBIDDEN');

require(msg.sender == feeToSetter, 'Palm: FORBIDDEN');

feeToSetter = _feeToSetter;

}

Saved diffs

Original text

Open file

/**
 *Submitted for verification at BscScan.com on 2021-04-23
*/

/**
 *Submitted for verification at BscScan.com on 2021-04-22
*/

/**
 *Submitted for verification at BscScan.com on 2021-04-22
*/

/**
 *Submitted for verification at BscScan.com on 2020-09-19
*/

pragma solidity =0.5.16;


interface IPancakeFactory {
    event PairCreated(address indexed token0, address indexed token1, address pair, uint);

    function feeTo() external view returns (address);
    function feeToSetter() external view returns (address);

    function getPair(address tokenA, address tokenB) external view returns (address pair);
    function allPairs(uint) external view returns (address pair);
    function allPairsLength() external view returns (uint);

    function createPair(address tokenA, address tokenB) external returns (address pair);

    function setFeeTo(address) external;
    function setFeeToSetter(address) external;
}

interface IPancakePair {
    event Approval(address indexed owner, address indexed spender, uint value);
    event Transfer(address indexed from, address indexed to, uint value);

    function name() external pure returns (string memory);
    function symbol() external pure returns (string memory);
    function decimals() external pure returns (uint8);
    function totalSupply() external view returns (uint);
    function balanceOf(address owner) external view returns (uint);
    function allowance(address owner, address spender) external view returns (uint);

    function approve(address spender, uint value) external returns (bool);
    function transfer(address to, uint value) external returns (bool);
    function transferFrom(address from, address to, uint value) external returns (bool);

    function DOMAIN_SEPARATOR() external view returns (bytes32);
    function PERMIT_TYPEHASH() external pure returns (bytes32);
    function nonces(address owner) external view returns (uint);

    function permit(address owner, address spender, uint value, uint deadline, uint8 v, bytes32 r, bytes32 s) external;

    event Mint(address indexed sender, uint amount0, uint amount1);
    event Burn(address indexed sender, uint amount0, uint amount1, address indexed to);
    event Swap(
        address indexed sender,
        uint amount0In,
        uint amount1In,
        uint amount0Out,
        uint amount1Out,
        address indexed to
    );
    event Sync(uint112 reserve0, uint112 reserve1);

    function MINIMUM_LIQUIDITY() external pure returns (uint);
    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, uint32 blockTimestampLast);
    function price0CumulativeLast() external view returns (uint);
    function price1CumulativeLast() external view returns (uint);
    function kLast() external view returns (uint);

    function mint(address to) external returns (uint liquidity);
    function burn(address to) external returns (uint amount0, uint amount1);
    function swap(uint amount0Out, uint amount1Out, address to, bytes calldata data) external;
    function skim(address to) external;
    function sync() external;

    function initialize(address, address) external;
}

interface IPancakeERC20 {
    event Approval(address indexed owner, address indexed spender, uint value);
    event Transfer(address indexed from, address indexed to, uint value);

    function name() external pure returns (string memory);
    function symbol() external pure returns (string memory);
    function decimals() external pure returns (uint8);
    function totalSupply() external view returns (uint);
    function balanceOf(address owner) external view returns (uint);
    function allowance(address owner, address spender) external view returns (uint);

    function approve(address spender, uint value) external returns (bool);
    function transfer(address to, uint value) external returns (bool);
    function transferFrom(address from, address to, uint value) external returns (bool);

    function DOMAIN_SEPARATOR() external view returns (bytes32);
    function PERMIT_TYPEHASH() external pure returns (bytes32);
    function nonces(address owner) external view returns (uint);

    function permit(address owner, address spender, uint value, uint deadline, uint8 v, bytes32 r, bytes32 s) external;
}

// a library for performing overflow-safe math, courtesy of DappHub (https://github.com/dapphub/ds-math)
library SafeMath {
    function add(uint x, uint y) internal pure returns (uint z) {
        require((z = x + y) >= x, 'ds-math-add-overflow');
    }

    function sub(uint x, uint y) internal pure returns (uint z) {
        require((z = x - y) <= x, 'ds-math-sub-underflow');
    }

    function mul(uint x, uint y) internal pure returns (uint z) {
        require(y == 0 || (z = x * y) / y == x, 'ds-math-mul-overflow');
    }
}

contract PancakeERC20 is IPancakeERC20 {
    using SafeMath for uint;

    string public constant name = 'Pancake LPs';
    string public constant symbol = 'Cake-LP';
    uint8 public constant decimals = 18;
    uint  public totalSupply;
    mapping(address => uint) public balanceOf;
    mapping(address => mapping(address => uint)) public allowance;

    bytes32 public DOMAIN_SEPARATOR;
    // keccak256("Permit(address owner,address spender,uint256 value,uint256 nonce,uint256 deadline)");
    bytes32 public constant PERMIT_TYPEHASH = 0x6e71edae12b1b97f4d1f60370fef10105fa2faae0126114a169c64845d6126c9;
    mapping(address => uint) public nonces;

    event Approval(address indexed owner, address indexed spender, uint value);
    event Transfer(address indexed from, address indexed to, uint value);

    constructor() public {
        uint chainId;
        assembly {
            chainId := chainid
        }
        DOMAIN_SEPARATOR = keccak256(
            abi.encode(
                keccak256('EIP712Domain(string name,string version,uint256 chainId,address verifyingContract)'),
                keccak256(bytes(name)),
                keccak256(bytes('1')),
                chainId,
                address(this)
            )
        );
    }

    function _mint(address to, uint value) internal {
        totalSupply = totalSupply.add(value);
        balanceOf[to] = balanceOf[to].add(value);
        emit Transfer(address(0), to, value);
    }

    function _burn(address from, uint value) internal {
        balanceOf[from] = balanceOf[from].sub(value);
        totalSupply = totalSupply.sub(value);
        emit Transfer(from, address(0), value);
    }

    function _approve(address owner, address spender, uint value) private {
        allowance[owner][spender] = value;
        emit Approval(owner, spender, value);
    }

    function _transfer(address from, address to, uint value) private {
        balanceOf[from] = balanceOf[from].sub(value);
        balanceOf[to] = balanceOf[to].add(value);
        emit Transfer(from, to, value);
    }

    function approve(address spender, uint value) external returns (bool) {
        _approve(msg.sender, spender, value);
        return true;
    }

    function transfer(address to, uint value) external returns (bool) {
        _transfer(msg.sender, to, value);
        return true;
    }

    function transferFrom(address from, address to, uint value) external returns (bool) {
        if (allowance[from][msg.sender] != uint(-1)) {
            allowance[from][msg.sender] = allowance[from][msg.sender].sub(value);
        }
        _transfer(from, to, value);
        return true;
    }

    function permit(address owner, address spender, uint value, uint deadline, uint8 v, bytes32 r, bytes32 s) external {
        require(deadline >= block.timestamp, 'Pancake: EXPIRED');
        bytes32 digest = keccak256(
            abi.encodePacked(
                '\x19\x01',
                DOMAIN_SEPARATOR,
                keccak256(abi.encode(PERMIT_TYPEHASH, owner, spender, value, nonces[owner]++, deadline))
            )
        );
        address recoveredAddress = ecrecover(digest, v, r, s);
        require(recoveredAddress != address(0) && recoveredAddress == owner, 'Pancake: INVALID_SIGNATURE');
        _approve(owner, spender, value);
    }
}

// a library for performing various math operations
library Math {
    function min(uint x, uint y) internal pure returns (uint z) {
        z = x < y ? x : y;
    }

    // babylonian method (https://en.wikipedia.org/wiki/Methods_of_computing_square_roots#Babylonian_method)
    function sqrt(uint y) internal pure returns (uint z) {
        if (y > 3) {
            z = y;
            uint x = y / 2 + 1;
            while (x < z) {
                z = x;
                x = (y / x + x) / 2;
            }
        } else if (y != 0) {
            z = 1;
        }
    }
}

// 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);
    }
}

interface IERC20 {
    event Approval(address indexed owner, address indexed spender, uint value);
    event Transfer(address indexed from, address indexed to, uint value);

    function name() external view returns (string memory);
    function symbol() external view returns (string memory);
    function decimals() external view returns (uint8);
    function totalSupply() external view returns (uint);
    function balanceOf(address owner) external view returns (uint);
    function allowance(address owner, address spender) external view returns (uint);

    function approve(address spender, uint value) external returns (bool);
    function transfer(address to, uint value) external returns (bool);
    function transferFrom(address from, address to, uint value) external returns (bool);
}

interface IPancakeCallee {
    function pancakeCall(address sender, uint amount0, uint amount1, bytes calldata data) external;
}

contract PancakePair is IPancakePair, PancakeERC20 {
    using SafeMath  for uint;
    using UQ112x112 for uint224;

    uint public constant MINIMUM_LIQUIDITY = 10**3;
    bytes4 private constant SELECTOR = bytes4(keccak256(bytes('transfer(address,uint256)')));

    address public factory;
    address public token0;
    address public token1;

    uint112 private reserve0;           // uses single storage slot, accessible via getReserves
    uint112 private reserve1;           // uses single storage slot, accessible via getReserves
    uint32  private blockTimestampLast; // uses single storage slot, accessible via getReserves

    uint public price0CumulativeLast;
    uint public price1CumulativeLast;
    uint public kLast; // reserve0 * reserve1, as of immediately after the most recent liquidity event

    uint private unlocked = 1;
    modifier lock() {
        require(unlocked == 1, 'Pancake: LOCKED');
        unlocked = 0;
        _;
        unlocked = 1;
    }

    function getReserves() public view returns (uint112 _reserve0, uint112 _reserve1, uint32 _blockTimestampLast) {
        _reserve0 = reserve0;
        _reserve1 = reserve1;
        _blockTimestampLast = blockTimestampLast;
    }

    function _safeTransfer(address token, address to, uint value) private {
        (bool success, bytes memory data) = token.call(abi.encodeWithSelector(SELECTOR, to, value));
        require(success && (data.length == 0 || abi.decode(data, (bool))), 'Pancake: TRANSFER_FAILED');
    }

    event Mint(address indexed sender, uint amount0, uint amount1);
    event Burn(address indexed sender, uint amount0, uint amount1, address indexed to);
    event Swap(
        address indexed sender,
        uint amount0In,
        uint amount1In,
        uint amount0Out,
        uint amount1Out,
        address indexed to
    );
    event Sync(uint112 reserve0, uint112 reserve1);

    constructor() public {
        factory = msg.sender;
    }

    // called once by the factory at time of deployment
    function initialize(address _token0, address _token1) external {
        require(msg.sender == factory, 'Pancake: FORBIDDEN'); // sufficient check
        token0 = _token0;
        token1 = _token1;
    }

    // update reserves and, on the first call per block, price accumulators
    function _update(uint balance0, uint balance1, uint112 _reserve0, uint112 _reserve1) private {
        require(balance0 <= uint112(-1) && balance1 <= uint112(-1), 'Pancake: OVERFLOW');
        uint32 blockTimestamp = uint32(block.timestamp % 2**32);
        uint32 timeElapsed = blockTimestamp - blockTimestampLast; // overflow is desired
        if (timeElapsed > 0 && _reserve0 != 0 && _reserve1 != 0) {
            // * never overflows, and + overflow is desired
            price0CumulativeLast += uint(UQ112x112.encode(_reserve1).uqdiv(_reserve0)) * timeElapsed;
            price1CumulativeLast += uint(UQ112x112.encode(_reserve0).uqdiv(_reserve1)) * timeElapsed;
        }
        reserve0 = uint112(balance0);
        reserve1 = uint112(balance1);
        blockTimestampLast = blockTimestamp;
        emit Sync(reserve0, reserve1);
    }

    // if fee is on, mint liquidity equivalent to 8/25 of the growth in sqrt(k)
    function _mintFee(uint112 _reserve0, uint112 _reserve1) private returns (bool feeOn) {
        address feeTo = IPancakeFactory(factory).feeTo();
        feeOn = feeTo != address(0);
        uint _kLast = kLast; // gas savings
        if (feeOn) {
            if (_kLast != 0) {
                uint rootK = Math.sqrt(uint(_reserve0).mul(_reserve1));
                uint rootKLast = Math.sqrt(_kLast);
                if (rootK > rootKLast) {
                    uint numerator = totalSupply.mul(rootK.sub(rootKLast)).mul(8);
                    uint denominator = rootK.mul(17).add(rootKLast.mul(8));
                    uint liquidity = numerator / denominator;
                    if (liquidity > 0) _mint(feeTo, liquidity);
                }
            }
        } else if (_kLast != 0) {
            kLast = 0;
        }
    }

    // this low-level function should be called from a contract which performs important safety checks
    function mint(address to) external lock returns (uint liquidity) {
        (uint112 _reserve0, uint112 _reserve1,) = getReserves(); // gas savings
        uint balance0 = IERC20(token0).balanceOf(address(this));
        uint balance1 = IERC20(token1).balanceOf(address(this));
        uint amount0 = balance0.sub(_reserve0);
        uint amount1 = balance1.sub(_reserve1);

        bool feeOn = _mintFee(_reserve0, _reserve1);
        uint _totalSupply = totalSupply; // gas savings, must be defined here since totalSupply can update in _mintFee
        if (_totalSupply == 0) {
            liquidity = Math.sqrt(amount0.mul(amount1)).sub(MINIMUM_LIQUIDITY);
           _mint(address(0), MINIMUM_LIQUIDITY); // permanently lock the first MINIMUM_LIQUIDITY tokens
        } else {
            liquidity = Math.min(amount0.mul(_totalSupply) / _reserve0, amount1.mul(_totalSupply) / _reserve1);
        }
        require(liquidity > 0, 'Pancake: INSUFFICIENT_LIQUIDITY_MINTED');
        _mint(to, liquidity);

        _update(balance0, balance1, _reserve0, _reserve1);
        if (feeOn) kLast = uint(reserve0).mul(reserve1); // reserve0 and reserve1 are up-to-date
        emit Mint(msg.sender, amount0, amount1);
    }

    // this low-level function should be called from a contract which performs important safety checks
    function burn(address to) external lock returns (uint amount0, uint amount1) {
        (uint112 _reserve0, uint112 _reserve1,) = getReserves(); // gas savings
        address _token0 = token0;                                // gas savings
        address _token1 = token1;                                // gas savings
        uint balance0 = IERC20(_token0).balanceOf(address(this));
        uint balance1 = IERC20(_token1).balanceOf(address(this));
        uint liquidity = balanceOf[address(this)];

        bool feeOn = _mintFee(_reserve0, _reserve1);
        uint _totalSupply = totalSupply; // gas savings, must be defined here since totalSupply can update in _mintFee
        amount0 = liquidity.mul(balance0) / _totalSupply; // using balances ensures pro-rata distribution
        amount1 = liquidity.mul(balance1) / _totalSupply; // using balances ensures pro-rata distribution
        require(amount0 > 0 && amount1 > 0, 'Pancake: 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, _reserve0, _reserve1);
        if (feeOn) kLast = uint(reserve0).mul(reserve1); // reserve0 and reserve1 are up-to-date
        emit Burn(msg.sender, amount0, amount1, to);
    }

    // this low-level function should be called from a contract which performs important safety checks
    function swap(uint amount0Out, uint amount1Out, address to, bytes calldata data) external lock {
        require(amount0Out > 0 || amount1Out > 0, 'Pancake: INSUFFICIENT_OUTPUT_AMOUNT');
        (uint112 _reserve0, uint112 _reserve1,) = getReserves(); // gas savings
        require(amount0Out < _reserve0 && amount1Out < _reserve1, 'Pancake: INSUFFICIENT_LIQUIDITY');

        uint balance0;
        uint balance1;
        { // scope for _token{0,1}, avoids stack too deep errors
        address _token0 = token0;
        address _token1 = token1;
        require(to != _token0 && to != _token1, 'Pancake: INVALID_TO');
        if (amount0Out > 0) _safeTransfer(_token0, to, amount0Out); // optimistically transfer tokens
        if (amount1Out > 0) _safeTransfer(_token1, to, amount1Out); // optimistically transfer tokens
        if (data.length > 0) IPancakeCallee(to).pancakeCall(msg.sender, amount0Out, amount1Out, data);
        balance0 = IERC20(_token0).balanceOf(address(this));
        balance1 = IERC20(_token1).balanceOf(address(this));
        }
        uint amount0In = balance0 > _reserve0 - amount0Out ? balance0 - (_reserve0 - amount0Out) : 0;
        uint amount1In = balance1 > _reserve1 - amount1Out ? balance1 - (_reserve1 - amount1Out) : 0;
        require(amount0In > 0 || amount1In > 0, 'Pancake: INSUFFICIENT_INPUT_AMOUNT');
        { // scope for reserve{0,1}Adjusted, avoids stack too deep errors
        uint balance0Adjusted = (balance0.mul(10000).sub(amount0In.mul(25)));
        uint balance1Adjusted = (balance1.mul(10000).sub(amount1In.mul(25)));
        require(balance0Adjusted.mul(balance1Adjusted) >= uint(_reserve0).mul(_reserve1).mul(10000**2), 'Pancake: K');
        }

        _update(balance0, balance1, _reserve0, _reserve1);
        emit Swap(msg.sender, amount0In, amount1In, amount0Out, amount1Out, to);
    }

    // force balances to match reserves
    function skim(address to) external lock {
        address _token0 = token0; // gas savings
        address _token1 = token1; // gas savings
        _safeTransfer(_token0, to, IERC20(_token0).balanceOf(address(this)).sub(reserve0));
        _safeTransfer(_token1, to, IERC20(_token1).balanceOf(address(this)).sub(reserve1));
    }

    // force reserves to match balances
    function sync() external lock {
        _update(IERC20(token0).balanceOf(address(this)), IERC20(token1).balanceOf(address(this)), reserve0, reserve1);
    }
}

contract PancakeFactory is IPancakeFactory {
    bytes32 public constant INIT_CODE_PAIR_HASH = keccak256(abi.encodePacked(type(PancakePair).creationCode));

    address public feeTo;
    address public feeToSetter;

    mapping(address => mapping(address => address)) public getPair;
    address[] public allPairs;

    event PairCreated(address indexed token0, address indexed token1, address pair, uint);

    constructor(address _feeToSetter) public {
        feeToSetter = _feeToSetter;
    }

    function allPairsLength() external view returns (uint) {
        return allPairs.length;
    }

    function createPair(address tokenA, address tokenB) external returns (address pair) {
        require(tokenA != tokenB, 'Pancake: IDENTICAL_ADDRESSES');
        (address token0, address token1) = tokenA < tokenB ? (tokenA, tokenB) : (tokenB, tokenA);
        require(token0 != address(0), 'Pancake: ZERO_ADDRESS');
        require(getPair[token0][token1] == address(0), 'Pancake: PAIR_EXISTS'); // single check is sufficient
        bytes memory bytecode = type(PancakePair).creationCode;
        bytes32 salt = keccak256(abi.encodePacked(token0, token1));
        assembly {
            pair := create2(0, add(bytecode, 32), mload(bytecode), salt)
        }
        IPancakePair(pair).initialize(token0, token1);
        getPair[token0][token1] = pair;
        getPair[token1][token0] = pair; // populate mapping in the reverse direction
        allPairs.push(pair);
        emit PairCreated(token0, token1, pair, allPairs.length);
    }

    function setFeeTo(address _feeTo) external {
        require(msg.sender == feeToSetter, 'Pancake: FORBIDDEN');
        feeTo = _feeTo;
    }

    function setFeeToSetter(address _feeToSetter) external {
        require(msg.sender == feeToSetter, 'Pancake: FORBIDDEN');
        feeToSetter = _feeToSetter;
    }
}

Changed text

Open file

pragma solidity =0.5.16;


interface IPalmFactory {
    event PairCreated(address indexed token0, address indexed token1, address pair, uint);

    function feeTo() external view returns (address);
    function burnFeeTo() external view returns (address);
    function feeToSetter() external view returns (address);

    function getPair(address tokenA, address tokenB) external view returns (address pair);
    function allPairs(uint) external view returns (address pair);
    function allPairsLength() external view returns (uint);

    function createPair(address tokenA, address tokenB) external returns (address pair);

    function setFeeTo(address) external;
    function setBurnFeeTo(address) external;
    function setFeeToSetter(address) external;
}

interface IPalmPair {
    event Approval(address indexed owner, address indexed spender, uint value);
    event Transfer(address indexed from, address indexed to, uint value);

    function name() external pure returns (string memory);
    function symbol() external pure returns (string memory);
    function decimals() external pure returns (uint8);
    function totalSupply() external view returns (uint);
    function balanceOf(address owner) external view returns (uint);
    function allowance(address owner, address spender) external view returns (uint);

    function approve(address spender, uint value) external returns (bool);
    function transfer(address to, uint value) external returns (bool);
    function transferFrom(address from, address to, uint value) external returns (bool);

    function DOMAIN_SEPARATOR() external view returns (bytes32);
    function PERMIT_TYPEHASH() external pure returns (bytes32);
    function nonces(address owner) external view returns (uint);

    function permit(address owner, address spender, uint value, uint deadline, uint8 v, bytes32 r, bytes32 s) external;

    event Mint(address indexed sender, uint amount0, uint amount1);
    event Burn(address indexed sender, uint amount0, uint amount1, address indexed to);
    event Swap(
        address indexed sender,
        uint amount0In,
        uint amount1In,
        uint amount0Out,
        uint amount1Out,
        address indexed to
    );
    event Sync(uint112 reserve0, uint112 reserve1);

    function MINIMUM_LIQUIDITY() external pure returns (uint);
    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, uint32 blockTimestampLast);
    function price0CumulativeLast() external view returns (uint);
    function price1CumulativeLast() external view returns (uint);
    function kLast() external view returns (uint);

    function mint(address to) external returns (uint liquidity);
    function burn(address to) external returns (uint amount0, uint amount1);
    function swap(uint amount0Out, uint amount1Out, address to, bytes calldata data) external;
    function skim(address to) external;
    function sync() external;

    function initialize(address, address) external;
}

interface IPalmERC20 {
    event Approval(address indexed owner, address indexed spender, uint value);
    event Transfer(address indexed from, address indexed to, uint value);

    function name() external pure returns (string memory);
    function symbol() external pure returns (string memory);
    function decimals() external pure returns (uint8);
    function totalSupply() external view returns (uint);
    function balanceOf(address owner) external view returns (uint);
    function allowance(address owner, address spender) external view returns (uint);

    function approve(address spender, uint value) external returns (bool);
    function transfer(address to, uint value) external returns (bool);
    function transferFrom(address from, address to, uint value) external returns (bool);

    function DOMAIN_SEPARATOR() external view returns (bytes32);
    function PERMIT_TYPEHASH() external pure returns (bytes32);
    function nonces(address owner) external view returns (uint);

    function permit(address owner, address spender, uint value, uint deadline, uint8 v, bytes32 r, bytes32 s) external;
}

// a library for performing overflow-safe math, courtesy of DappHub (https://github.com/dapphub/ds-math)
library SafeMath {
    function add(uint x, uint y) internal pure returns (uint z) {
        require((z = x + y) >= x, 'ds-math-add-overflow');
    }

    function sub(uint x, uint y) internal pure returns (uint z) {
        require((z = x - y) <= x, 'ds-math-sub-underflow');
    }

    function mul(uint x, uint y) internal pure returns (uint z) {
        require(y == 0 || (z = x * y) / y == x, 'ds-math-mul-overflow');
    }
}

contract PalmERC20 is IPalmERC20 {
    using SafeMath for uint;

    string public constant name = 'Palm LPs';
    string public constant symbol = 'Palm-LP';
    uint8 public constant decimals = 18;
    uint  public totalSupply;
    mapping(address => uint) public balanceOf;
    mapping(address => mapping(address => uint)) public allowance;

    bytes32 public DOMAIN_SEPARATOR;
    // keccak256("Permit(address owner,address spender,uint256 value,uint256 nonce,uint256 deadline)");
    bytes32 public constant PERMIT_TYPEHASH = 0x6e71edae12b1b97f4d1f60370fef10105fa2faae0126114a169c64845d6126c9;
    mapping(address => uint) public nonces;

    event Approval(address indexed owner, address indexed spender, uint value);
    event Transfer(address indexed from, address indexed to, uint value);

    constructor() public {
        uint chainId;
        assembly {
            chainId := chainid
        }
        DOMAIN_SEPARATOR = keccak256(
            abi.encode(
                keccak256('EIP712Domain(string name,string version,uint256 chainId,address verifyingContract)'),
                keccak256(bytes(name)),
                keccak256(bytes('1')),
                chainId,
                address(this)
            )
        );
    }

    function _mint(address to, uint value) internal {
        totalSupply = totalSupply.add(value);
        balanceOf[to] = balanceOf[to].add(value);
        emit Transfer(address(0), to, value);
    }

    function _burn(address from, uint value) internal {
        balanceOf[from] = balanceOf[from].sub(value);
        totalSupply = totalSupply.sub(value);
        emit Transfer(from, address(0), value);
    }

    function _approve(address owner, address spender, uint value) private {
        allowance[owner][spender] = value;
        emit Approval(owner, spender, value);
    }

    function _transfer(address from, address to, uint value) private {
        balanceOf[from] = balanceOf[from].sub(value);
        balanceOf[to] = balanceOf[to].add(value);
        emit Transfer(from, to, value);
    }

    function approve(address spender, uint value) external returns (bool) {
        _approve(msg.sender, spender, value);
        return true;
    }

    function transfer(address to, uint value) external returns (bool) {
        _transfer(msg.sender, to, value);
        return true;
    }

    function transferFrom(address from, address to, uint value) external returns (bool) {
        if (allowance[from][msg.sender] != uint(-1)) {
            allowance[from][msg.sender] = allowance[from][msg.sender].sub(value);
        }
        _transfer(from, to, value);
        return true;
    }

    function permit(address owner, address spender, uint value, uint deadline, uint8 v, bytes32 r, bytes32 s) external {
        require(deadline >= block.timestamp, 'Palm: EXPIRED');
        bytes32 digest = keccak256(
            abi.encodePacked(
                '\x19\x01',
                DOMAIN_SEPARATOR,
                keccak256(abi.encode(PERMIT_TYPEHASH, owner, spender, value, nonces[owner]++, deadline))
            )
        );
        address recoveredAddress = ecrecover(digest, v, r, s);
        require(recoveredAddress != address(0) && recoveredAddress == owner, 'Palm: INVALID_SIGNATURE');
        _approve(owner, spender, value);
    }
}

// a library for performing various math operations
library Math {
    function min(uint x, uint y) internal pure returns (uint z) {
        z = x < y ? x : y;
    }

    // babylonian method (https://en.wikipedia.org/wiki/Methods_of_computing_square_roots#Babylonian_method)
    function sqrt(uint y) internal pure returns (uint z) {
        if (y > 3) {
            z = y;
            uint x = y / 2 + 1;
            while (x < z) {
                z = x;
                x = (y / x + x) / 2;
            }
        } else if (y != 0) {
            z = 1;
        }
    }
}

// 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);
    }
}

interface IERC20 {
    event Approval(address indexed owner, address indexed spender, uint value);
    event Transfer(address indexed from, address indexed to, uint value);

    function name() external view returns (string memory);
    function symbol() external view returns (string memory);
    function decimals() external view returns (uint8);
    function totalSupply() external view returns (uint);
    function balanceOf(address owner) external view returns (uint);
    function allowance(address owner, address spender) external view returns (uint);

    function approve(address spender, uint value) external returns (bool);
    function transfer(address to, uint value) external returns (bool);
    function transferFrom(address from, address to, uint value) external returns (bool);
}

interface IPalmCallee {
    function PalmCall(address sender, uint amount0, uint amount1, bytes calldata data) external;
}

contract PalmPair is IPalmPair, PalmERC20 {
    using SafeMath  for uint;
    using UQ112x112 for uint224;

    uint public constant MINIMUM_LIQUIDITY = 10**3;
    bytes4 private constant SELECTOR = bytes4(keccak256(bytes('transfer(address,uint256)')));

    address public factory;
    address public token0;
    address public token1;

    uint112 private reserve0;           // uses single storage slot, accessible via getReserves
    uint112 private reserve1;           // uses single storage slot, accessible via getReserves
    uint32  private blockTimestampLast; // uses single storage slot, accessible via getReserves

    uint public price0CumulativeLast;
    uint public price1CumulativeLast;
    uint public kLast; // reserve0 * reserve1, as of immediately after the most recent liquidity event

    uint private unlocked = 1;
    modifier lock() {
        require(unlocked == 1, 'Palm: LOCKED');
        unlocked = 0;
        _;
        unlocked = 1;
    }

    function getReserves() public view returns (uint112 _reserve0, uint112 _reserve1, uint32 _blockTimestampLast) {
        _reserve0 = reserve0;
        _reserve1 = reserve1;
        _blockTimestampLast = blockTimestampLast;
    }

    function _safeTransfer(address token, address to, uint value) private {
        (bool success, bytes memory data) = token.call(abi.encodeWithSelector(SELECTOR, to, value));
        require(success && (data.length == 0 || abi.decode(data, (bool))), 'Palm: TRANSFER_FAILED');
    }

    event Mint(address indexed sender, uint amount0, uint amount1);
    event Burn(address indexed sender, uint amount0, uint amount1, address indexed to);
    event Swap(
        address indexed sender,
        uint amount0In,
        uint amount1In,
        uint amount0Out,
        uint amount1Out,
        address indexed to
    );
    event Sync(uint112 reserve0, uint112 reserve1);

    constructor() public {
        factory = msg.sender;
    }

    // called once by the factory at time of deployment
    function initialize(address _token0, address _token1) external {
        require(msg.sender == factory, 'Palm: FORBIDDEN'); // sufficient check
        token0 = _token0;
        token1 = _token1;
    }

    // update reserves and, on the first call per block, price accumulators
    function _update(uint balance0, uint balance1, uint112 _reserve0, uint112 _reserve1) private {
        require(balance0 <= uint112(-1) && balance1 <= uint112(-1), 'Palm: OVERFLOW');
        uint32 blockTimestamp = uint32(block.timestamp % 2**32);
        uint32 timeElapsed = blockTimestamp - blockTimestampLast; // overflow is desired
        if (timeElapsed > 0 && _reserve0 != 0 && _reserve1 != 0) {
            // * never overflows, and + overflow is desired
            price0CumulativeLast += uint(UQ112x112.encode(_reserve1).uqdiv(_reserve0)) * timeElapsed;
            price1CumulativeLast += uint(UQ112x112.encode(_reserve0).uqdiv(_reserve1)) * timeElapsed;
        }
        reserve0 = uint112(balance0);
        reserve1 = uint112(balance1);
        blockTimestampLast = blockTimestamp;
        emit Sync(reserve0, reserve1);
    }

    // if fee is on, mint liquidity equivalent to 20/25 of the growth in sqrt(k)
    function _mintFee(uint112 _reserve0, uint112 _reserve1) private returns (bool feeOn) {
        address feeTo = IPalmFactory(factory).feeTo();
        address burnFeeTo = IPalmFactory(factory).burnFeeTo();
        feeOn = feeTo != address(0) && burnFeeTo != address(0);
        uint _kLast = kLast; // gas savings
        if (feeOn) {
            if (_kLast != 0) {
                uint rootK = Math.sqrt(uint(_reserve0).mul(_reserve1));
                uint rootKLast = Math.sqrt(_kLast);
                if (rootK > rootKLast) {
                    uint numerator = totalSupply.mul(rootK.sub(rootKLast)).mul(22);
                    uint denominator = rootK.mul(17).add(rootKLast.mul(8));
                    uint liquidity = numerator / denominator;
                    if (liquidity > 0) {

						uint burnFee = ((liquidity.mul(75)) / 100);

						liquidity = liquidity.sub(burnFee);
						_mint(burnFeeTo, burnFee);
						_mint(feeTo, liquidity);
						
					}
                }
            }
        } else if (_kLast != 0) {
            kLast = 0;
        }
    }

    // this low-level function should be called from a contract which performs important safety checks
    function mint(address to) external lock returns (uint liquidity) {
        (uint112 _reserve0, uint112 _reserve1,) = getReserves(); // gas savings
        uint balance0 = IERC20(token0).balanceOf(address(this));
        uint balance1 = IERC20(token1).balanceOf(address(this));
        uint amount0 = balance0.sub(_reserve0);
        uint amount1 = balance1.sub(_reserve1);

        bool feeOn = _mintFee(_reserve0, _reserve1);
        uint _totalSupply = totalSupply; // gas savings, must be defined here since totalSupply can update in _mintFee
        if (_totalSupply == 0) {
            liquidity = Math.sqrt(amount0.mul(amount1)).sub(MINIMUM_LIQUIDITY);
           _mint(address(0), MINIMUM_LIQUIDITY); // permanently lock the first MINIMUM_LIQUIDITY tokens
        } else {
            liquidity = Math.min(amount0.mul(_totalSupply) / _reserve0, amount1.mul(_totalSupply) / _reserve1);
        }
        require(liquidity > 0, 'Palm: INSUFFICIENT_LIQUIDITY_MINTED');
        _mint(to, liquidity);

        _update(balance0, balance1, _reserve0, _reserve1);
        if (feeOn) kLast = uint(reserve0).mul(reserve1); // reserve0 and reserve1 are up-to-date
        emit Mint(msg.sender, amount0, amount1);
    }

    // this low-level function should be called from a contract which performs important safety checks
    function burn(address to) external lock returns (uint amount0, uint amount1) {
        (uint112 _reserve0, uint112 _reserve1,) = getReserves(); // gas savings
        address _token0 = token0;                                // gas savings
        address _token1 = token1;                                // gas savings
        uint balance0 = IERC20(_token0).balanceOf(address(this));
        uint balance1 = IERC20(_token1).balanceOf(address(this));
        uint liquidity = balanceOf[address(this)];

        bool feeOn = _mintFee(_reserve0, _reserve1);
        uint _totalSupply = totalSupply; // gas savings, must be defined here since totalSupply can update in _mintFee
        amount0 = liquidity.mul(balance0) / _totalSupply; // using balances ensures pro-rata distribution
        amount1 = liquidity.mul(balance1) / _totalSupply; // using balances ensures pro-rata distribution
        require(amount0 > 0 && amount1 > 0, 'Palm: 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, _reserve0, _reserve1);
        if (feeOn) kLast = uint(reserve0).mul(reserve1); // reserve0 and reserve1 are up-to-date
        emit Burn(msg.sender, amount0, amount1, to);
    }

    // this low-level function should be called from a contract which performs important safety checks
    function swap(uint amount0Out, uint amount1Out, address to, bytes calldata data) external lock {
        require(amount0Out > 0 || amount1Out > 0, 'Palm: INSUFFICIENT_OUTPUT_AMOUNT');
        (uint112 _reserve0, uint112 _reserve1,) = getReserves(); // gas savings
        require(amount0Out < _reserve0 && amount1Out < _reserve1, 'Palm: INSUFFICIENT_LIQUIDITY');

        uint balance0;
        uint balance1;
        { // scope for _token{0,1}, avoids stack too deep errors
        address _token0 = token0;
        address _token1 = token1;
        require(to != _token0 && to != _token1, 'Palm: INVALID_TO');
        if (amount0Out > 0) _safeTransfer(_token0, to, amount0Out); // optimistically transfer tokens
        if (amount1Out > 0) _safeTransfer(_token1, to, amount1Out); // optimistically transfer tokens
        if (data.length > 0) IPalmCallee(to).PalmCall(msg.sender, amount0Out, amount1Out, data);
        balance0 = IERC20(_token0).balanceOf(address(this));
        balance1 = IERC20(_token1).balanceOf(address(this));
        }
        uint amount0In = balance0 > _reserve0 - amount0Out ? balance0 - (_reserve0 - amount0Out) : 0;
        uint amount1In = balance1 > _reserve1 - amount1Out ? balance1 - (_reserve1 - amount1Out) : 0;
        require(amount0In > 0 || amount1In > 0, 'Palm: INSUFFICIENT_INPUT_AMOUNT');
        { // scope for reserve{0,1}Adjusted, avoids stack too deep errors
        uint balance0Adjusted = (balance0.mul(10000).sub(amount0In.mul(25)));
        uint balance1Adjusted = (balance1.mul(10000).sub(amount1In.mul(25)));
        require(balance0Adjusted.mul(balance1Adjusted) >= uint(_reserve0).mul(_reserve1).mul(10000**2), 'Palm: K');
        }

        _update(balance0, balance1, _reserve0, _reserve1);
        emit Swap(msg.sender, amount0In, amount1In, amount0Out, amount1Out, to);
    }

    // force balances to match reserves
    function skim(address to) external lock {
        address _token0 = token0; // gas savings
        address _token1 = token1; // gas savings
        _safeTransfer(_token0, to, IERC20(_token0).balanceOf(address(this)).sub(reserve0));
        _safeTransfer(_token1, to, IERC20(_token1).balanceOf(address(this)).sub(reserve1));
    }

    // force reserves to match balances
    function sync() external lock {
        _update(IERC20(token0).balanceOf(address(this)), IERC20(token1).balanceOf(address(this)), reserve0, reserve1);
    }
}

contract PalmFactory is IPalmFactory {
    bytes32 public constant INIT_CODE_PAIR_HASH = keccak256(abi.encodePacked(type(PalmPair).creationCode));

    address public feeTo;
    address public burnFeeTo;
    address public feeToSetter;

    mapping(address => mapping(address => address)) public getPair;
    address[] public allPairs;

    event PairCreated(address indexed token0, address indexed token1, address pair, uint);

    constructor(address _feeToSetter) public {
        feeToSetter = _feeToSetter;
    }

    function allPairsLength() external view returns (uint) {
        return allPairs.length;
    }

    function createPair(address tokenA, address tokenB) external returns (address pair) {
        require(tokenA != tokenB, 'Palm: IDENTICAL_ADDRESSES');
        (address token0, address token1) = tokenA < tokenB ? (tokenA, tokenB) : (tokenB, tokenA);
        require(token0 != address(0), 'Palm: ZERO_ADDRESS');
        require(getPair[token0][token1] == address(0), 'Palm: PAIR_EXISTS'); // single check is sufficient
        bytes memory bytecode = type(PalmPair).creationCode;
        bytes32 salt = keccak256(abi.encodePacked(token0, token1));
        assembly {
            pair := create2(0, add(bytecode, 32), mload(bytecode), salt)
        }
        IPalmPair(pair).initialize(token0, token1);
        getPair[token0][token1] = pair;
        getPair[token1][token0] = pair; // populate mapping in the reverse direction
        allPairs.push(pair);
        emit PairCreated(token0, token1, pair, allPairs.length);
    }

    function setFeeTo(address _feeTo) external {
        require(msg.sender == feeToSetter, 'Palm: FORBIDDEN');
        feeTo = _feeTo;
    }

    function setBurnFeeTo(address _burnFeeTo) external {
        require(msg.sender == feeToSetter, 'Palm: FORBIDDEN');
        burnFeeTo = _burnFeeTo;
    }

    function setFeeToSetter(address _feeToSetter) external {
        require(msg.sender == feeToSetter, 'Palm: FORBIDDEN');
        feeToSetter = _feeToSetter;
    }
}