File 1 of 1: Mooniswap.sol
pragma solidity ^0.6.0;
abstract contract Context {
function _msgSender() internal view virtual returns (address payable) {
return msg.sender;
}
function _msgData() internal view virtual returns (bytes memory) {
this;
return msg.data;
}
}
pragma solidity ^0.6.0;
contract Ownable is Context {
address private _owner;
event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);
constructor () internal {
address msgSender = _msgSender();
_owner = msgSender;
emit OwnershipTransferred(address(0), msgSender);
}
function owner() public view returns (address) {
return _owner;
}
modifier onlyOwner() {
require(_owner == _msgSender(), "Ownable: caller is not the owner");
_;
}
function renounceOwnership() public virtual onlyOwner {
emit OwnershipTransferred(_owner, address(0));
_owner = address(0);
}
function transferOwnership(address newOwner) public virtual onlyOwner {
require(newOwner != address(0), "Ownable: new owner is the zero address");
emit OwnershipTransferred(_owner, newOwner);
_owner = newOwner;
}
}
pragma solidity ^0.6.0;
contract ReentrancyGuard {
uint256 private constant _NOT_ENTERED = 1;
uint256 private constant _ENTERED = 2;
uint256 private _status;
constructor () internal {
_status = _NOT_ENTERED;
}
modifier nonReentrant() {
require(_status != _ENTERED, "ReentrancyGuard: reentrant call");
_status = _ENTERED;
_;
_status = _NOT_ENTERED;
}
}
pragma solidity ^0.6.0;
library Math {
function max(uint256 a, uint256 b) internal pure returns (uint256) {
return a >= b ? a : b;
}
function min(uint256 a, uint256 b) internal pure returns (uint256) {
return a < b ? a : b;
}
function average(uint256 a, uint256 b) internal pure returns (uint256) {
return (a / 2) + (b / 2) + ((a % 2 + b % 2) / 2);
}
}
pragma solidity ^0.6.0;
library SafeMath {
function add(uint256 a, uint256 b) internal pure returns (uint256) {
uint256 c = a + b;
require(c >= a, "SafeMath: addition overflow");
return c;
}
function sub(uint256 a, uint256 b) internal pure returns (uint256) {
return sub(a, b, "SafeMath: subtraction overflow");
}
function sub(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
require(b <= a, errorMessage);
uint256 c = a - b;
return c;
}
function mul(uint256 a, uint256 b) internal pure returns (uint256) {
if (a == 0) {
return 0;
}
uint256 c = a * b;
require(c / a == b, "SafeMath: multiplication overflow");
return c;
}
function div(uint256 a, uint256 b) internal pure returns (uint256) {
return div(a, b, "SafeMath: division by zero");
}
function div(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
require(b > 0, errorMessage);
uint256 c = a / b;
return c;
}
function mod(uint256 a, uint256 b) internal pure returns (uint256) {
return mod(a, b, "SafeMath: modulo by zero");
}
function mod(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
require(b != 0, errorMessage);
return a % b;
}
}
pragma solidity ^0.6.0;
interface IERC20 {
function totalSupply() external view returns (uint256);
function balanceOf(address account) external view returns (uint256);
function transfer(address recipient, uint256 amount) external returns (bool);
function allowance(address owner, address spender) external view returns (uint256);
function approve(address spender, uint256 amount) external returns (bool);
function transferFrom(address sender, address recipient, uint256 amount) external returns (bool);
event Transfer(address indexed from, address indexed to, uint256 value);
event Approval(address indexed owner, address indexed spender, uint256 value);
}
pragma solidity ^0.6.2;
library Address {
function isContract(address account) internal view returns (bool) {
bytes32 codehash;
bytes32 accountHash = 0xc5d2460186f7233c927e7db2dcc703c0e500b653ca82273b7bfad8045d85a470;
assembly { codehash := extcodehash(account) }
return (codehash != accountHash && codehash != 0x0);
}
function sendValue(address payable recipient, uint256 amount) internal {
require(address(this).balance >= amount, "Address: insufficient balance");
(bool success, ) = recipient.call{ value: amount }("");
require(success, "Address: unable to send value, recipient may have reverted");
}
function functionCall(address target, bytes memory data) internal returns (bytes memory) {
return functionCall(target, data, "Address: low-level call failed");
}
function functionCall(address target, bytes memory data, string memory errorMessage) internal returns (bytes memory) {
return _functionCallWithValue(target, data, 0, errorMessage);
}
function functionCallWithValue(address target, bytes memory data, uint256 value) internal returns (bytes memory) {
return functionCallWithValue(target, data, value, "Address: low-level call with value failed");
}
function functionCallWithValue(address target, bytes memory data, uint256 value, string memory errorMessage) internal returns (bytes memory) {
require(address(this).balance >= value, "Address: insufficient balance for call");
return _functionCallWithValue(target, data, value, errorMessage);
}
function _functionCallWithValue(address target, bytes memory data, uint256 weiValue, string memory errorMessage) private returns (bytes memory) {
require(isContract(target), "Address: call to non-contract");
(bool success, bytes memory returndata) = target.call{ value: weiValue }(data);
if (success) {
return returndata;
} else {
if (returndata.length > 0) {
assembly {
let returndata_size := mload(returndata)
revert(add(32, returndata), returndata_size)
}
} else {
revert(errorMessage);
}
}
}
}
pragma solidity ^0.6.0;
contract ERC20 is Context, IERC20 {
using SafeMath for uint256;
using Address for address;
mapping (address => uint256) private _balances;
mapping (address => mapping (address => uint256)) private _allowances;
uint256 private _totalSupply;
string private _name;
string private _symbol;
uint8 private _decimals;
constructor (string memory name, string memory symbol) public {
_name = name;
_symbol = symbol;
_decimals = 18;
}
function name() public view returns (string memory) {
return _name;
}
function symbol() public view returns (string memory) {
return _symbol;
}
function decimals() public view returns (uint8) {
return _decimals;
}
function totalSupply() public view override returns (uint256) {
return _totalSupply;
}
function balanceOf(address account) public view override returns (uint256) {
return _balances[account];
}
function transfer(address recipient, uint256 amount) public virtual override returns (bool) {
_transfer(_msgSender(), recipient, amount);
return true;
}
function allowance(address owner, address spender) public view virtual override returns (uint256) {
return _allowances[owner][spender];
}
function approve(address spender, uint256 amount) public virtual override returns (bool) {
_approve(_msgSender(), spender, amount);
return true;
}
function transferFrom(address sender, address recipient, uint256 amount) public virtual override returns (bool) {
_transfer(sender, recipient, amount);
_approve(sender, _msgSender(), _allowances[sender][_msgSender()].sub(amount, "ERC20: transfer amount exceeds allowance"));
return true;
}
function increaseAllowance(address spender, uint256 addedValue) public virtual returns (bool) {
_approve(_msgSender(), spender, _allowances[_msgSender()][spender].add(addedValue));
return true;
}
function decreaseAllowance(address spender, uint256 subtractedValue) public virtual returns (bool) {
_approve(_msgSender(), spender, _allowances[_msgSender()][spender].sub(subtractedValue, "ERC20: decreased allowance below zero"));
return true;
}
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);
_balances[sender] = _balances[sender].sub(amount, "ERC20: transfer amount exceeds balance");
_balances[recipient] = _balances[recipient].add(amount);
emit Transfer(sender, recipient, amount);
}
function _mint(address account, uint256 amount) internal virtual {
require(account != address(0), "ERC20: mint to the zero address");
_beforeTokenTransfer(address(0), account, amount);
_totalSupply = _totalSupply.add(amount);
_balances[account] = _balances[account].add(amount);
emit Transfer(address(0), account, amount);
}
function _burn(address account, uint256 amount) internal virtual {
require(account != address(0), "ERC20: burn from the zero address");
_beforeTokenTransfer(account, address(0), amount);
_balances[account] = _balances[account].sub(amount, "ERC20: burn amount exceeds balance");
_totalSupply = _totalSupply.sub(amount);
emit Transfer(account, address(0), amount);
}
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);
}
function _setupDecimals(uint8 decimals_) internal {
_decimals = decimals_;
}
function _beforeTokenTransfer(address from, address to, uint256 amount) internal virtual { }
}
pragma solidity ^0.6.0;
library SafeERC20 {
using SafeMath for uint256;
using Address for address;
function safeTransfer(IERC20 token, address to, uint256 value) internal {
_callOptionalReturn(token, abi.encodeWithSelector(token.transfer.selector, to, value));
}
function safeTransferFrom(IERC20 token, address from, address to, uint256 value) internal {
_callOptionalReturn(token, abi.encodeWithSelector(token.transferFrom.selector, from, to, value));
}
function safeApprove(IERC20 token, address spender, uint256 value) internal {
require((value == 0) || (token.allowance(address(this), spender) == 0),
"SafeERC20: approve from non-zero to non-zero allowance"
);
_callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, value));
}
function safeIncreaseAllowance(IERC20 token, address spender, uint256 value) internal {
uint256 newAllowance = token.allowance(address(this), spender).add(value);
_callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
}
function safeDecreaseAllowance(IERC20 token, address spender, uint256 value) internal {
uint256 newAllowance = token.allowance(address(this), spender).sub(value, "SafeERC20: decreased allowance below zero");
_callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
}
function _callOptionalReturn(IERC20 token, bytes memory data) private {
bytes memory returndata = address(token).functionCall(data, "SafeERC20: low-level call failed");
if (returndata.length > 0) {
require(abi.decode(returndata, (bool)), "SafeERC20: ERC20 operation did not succeed");
}
}
}
pragma solidity ^0.6.0;
library UniERC20 {
using SafeMath for uint256;
using SafeERC20 for IERC20;
function isETH(IERC20 token) internal pure returns(bool) {
return (address(token) == address(0));
}
function uniBalanceOf(IERC20 token, address account) internal view returns (uint256) {
if (isETH(token)) {
return account.balance;
} else {
return token.balanceOf(account);
}
}
function uniTransfer(IERC20 token, address payable to, uint256 amount) internal {
if (amount > 0) {
if (isETH(token)) {
to.transfer(amount);
} else {
token.safeTransfer(to, amount);
}
}
}
function uniTransferFromSenderToThis(IERC20 token, uint256 amount) internal {
if (amount > 0) {
if (isETH(token)) {
require(msg.value >= amount, "UniERC20: not enough value");
if (msg.value > amount) {
msg.sender.transfer(msg.value.sub(amount));
}
} else {
token.safeTransferFrom(msg.sender, address(this), amount);
}
}
}
function uniSymbol(IERC20 token) internal view returns(string memory) {
if (isETH(token)) {
return "ETH";
}
(bool success, bytes memory data) = address(token).staticcall{ gas: 20000 }(
abi.encodeWithSignature("symbol()")
);
if (!success) {
(success, data) = address(token).staticcall{ gas: 20000 }(
abi.encodeWithSignature("SYMBOL()")
);
}
if (success && data.length >= 96) {
(uint256 offset, uint256 len) = abi.decode(data, (uint256, uint256));
if (offset == 0x20 && len > 0 && len <= 256) {
return string(abi.decode(data, (bytes)));
}
}
if (success && data.length == 32) {
uint len = 0;
while (len < data.length && data[len] >= 0x20 && data[len] <= 0x7E) {
len++;
}
if (len > 0) {
bytes memory result = new bytes(len);
for (uint i = 0; i < len; i++) {
result[i] = data[i];
}
return string(result);
}
}
return _toHex(address(token));
}
function _toHex(address account) private pure returns(string memory) {
return _toHex(abi.encodePacked(account));
}
function _toHex(bytes memory data) private pure returns(string memory) {
bytes memory str = new bytes(2 + data.length * 2);
str[0] = "0";
str[1] = "x";
uint j = 2;
for (uint i = 0; i < data.length; i++) {
uint a = uint8(data[i]) >> 4;
uint b = uint8(data[i]) & 0x0f;
str[j++] = byte(uint8(a + 48 + (a/10)*39));
str[j++] = byte(uint8(b + 48 + (b/10)*39));
}
return string(str);
}
}
pragma solidity ^0.6.0;
library Sqrt {
function sqrt(uint256 y) internal pure returns (uint256) {
if (y > 3) {
uint256 z = y;
uint256 x = y / 2 + 1;
while (x < z) {
z = x;
x = (y / x + x) / 2;
}
return z;
} else if (y != 0) {
return 1;
} else {
return 0;
}
}
}
pragma solidity ^0.6.0;
interface IFactory {
function fee() external view returns(uint256);
}
library VirtualBalance {
using SafeMath for uint256;
struct Data {
uint216 balance;
uint40 time;
}
uint256 public constant DECAY_PERIOD = 5 minutes;
function set(VirtualBalance.Data storage self, uint256 balance) internal {
self.balance = uint216(balance);
self.time = uint40(block.timestamp);
}
function update(VirtualBalance.Data storage self, uint256 realBalance) internal {
set(self, current(self, realBalance));
}
function scale(VirtualBalance.Data storage self, uint256 realBalance, uint256 num, uint256 denom) internal {
set(self, current(self, realBalance).mul(num).add(denom.sub(1)).div(denom));
}
function current(VirtualBalance.Data memory self, uint256 realBalance) internal view returns(uint256) {
uint256 timePassed = Math.min(DECAY_PERIOD, block.timestamp.sub(self.time));
uint256 timeRemain = DECAY_PERIOD.sub(timePassed);
return uint256(self.balance).mul(timeRemain).add(
realBalance.mul(timePassed)
).div(DECAY_PERIOD);
}
}
contract Mooniswap is ERC20, ReentrancyGuard, Ownable {
using Sqrt for uint256;
using SafeMath for uint256;
using UniERC20 for IERC20;
using VirtualBalance for VirtualBalance.Data;
struct Balances {
uint256 src;
uint256 dst;
}
struct SwapVolumes {
uint128 confirmed;
uint128 result;
}
event Deposited(
address indexed account,
uint256 amount
);
event Withdrawn(
address indexed account,
uint256 amount
);
event Swapped(
address indexed account,
address indexed src,
address indexed dst,
uint256 amount,
uint256 result,
uint256 srcBalance,
uint256 dstBalance,
uint256 totalSupply,
address referral
);
uint256 public constant REFERRAL_SHARE = 20;
uint256 public constant BASE_SUPPLY = 1000;
uint256 public constant FEE_DENOMINATOR = 1e18;
IFactory public factory;
IERC20[] public tokens;
mapping(IERC20 => bool) public isToken;
mapping(IERC20 => SwapVolumes) public volumes;
mapping(IERC20 => VirtualBalance.Data) public virtualBalancesForAddition;
mapping(IERC20 => VirtualBalance.Data) public virtualBalancesForRemoval;
constructor(IERC20[] memory assets, string memory name, string memory symbol) public ERC20(name, symbol) {
require(bytes(name).length > 0, "Mooniswap: name is empty");
require(bytes(symbol).length > 0, "Mooniswap: symbol is empty");
require(assets.length == 2, "Mooniswap: only 2 tokens allowed");
factory = IFactory(msg.sender);
tokens = assets;
for (uint i = 0; i < assets.length; i++) {
require(!isToken[assets[i]], "Mooniswap: duplicate tokens");
isToken[assets[i]] = true;
}
}
function fee() public view returns(uint256) {
return factory.fee();
}
function getTokens() external view returns(IERC20[] memory) {
return tokens;
}
function decayPeriod() external pure returns(uint256) {
return VirtualBalance.DECAY_PERIOD;
}
function getBalanceForAddition(IERC20 token) public view returns(uint256) {
uint256 balance = token.uniBalanceOf(address(this));
return Math.max(virtualBalancesForAddition[token].current(balance), balance);
}
function getBalanceForRemoval(IERC20 token) public view returns(uint256) {
uint256 balance = token.uniBalanceOf(address(this));
return Math.min(virtualBalancesForRemoval[token].current(balance), balance);
}
function getReturn(IERC20 src, IERC20 dst, uint256 amount) external view returns(uint256) {
return _getReturn(src, dst, amount, getBalanceForAddition(src), getBalanceForRemoval(dst));
}
function deposit(uint256[] calldata amounts, uint256[] calldata minAmounts) external payable nonReentrant returns(uint256 fairSupply) {
IERC20[] memory _tokens = tokens;
require(amounts.length == _tokens.length, "Mooniswap: wrong amounts length");
require(msg.value == (_tokens[0].isETH() ? amounts[0] : (_tokens[1].isETH() ? amounts[1] : 0)), "Mooniswap: wrong value usage");
uint256[] memory realBalances = new uint256[](amounts.length);
for (uint i = 0; i < realBalances.length; i++) {
realBalances[i] = _tokens[i].uniBalanceOf(address(this)).sub(_tokens[i].isETH() ? msg.value : 0);
}
uint256 totalSupply = totalSupply();
if (totalSupply == 0) {
fairSupply = BASE_SUPPLY.mul(99);
_mint(address(this), BASE_SUPPLY);
for (uint i = 0; i < amounts.length; i++) {
fairSupply = Math.max(fairSupply, amounts[i]);
}
}
else {
fairSupply = type(uint256).max;
for (uint i = 0; i < amounts.length; i++) {
fairSupply = Math.min(fairSupply, totalSupply.mul(amounts[i]).div(realBalances[i]));
}
}
uint256 fairSupplyCached = fairSupply;
for (uint i = 0; i < amounts.length; i++) {
require(amounts[i] > 0, "Mooniswap: amount is zero");
uint256 amount = (totalSupply == 0) ? amounts[i] :
realBalances[i].mul(fairSupplyCached).add(totalSupply - 1).div(totalSupply);
require(amount >= minAmounts[i], "Mooniswap: minAmount not reached");
_tokens[i].uniTransferFromSenderToThis(amount);
if (totalSupply > 0) {
uint256 confirmed = _tokens[i].uniBalanceOf(address(this)).sub(realBalances[i]);
fairSupply = Math.min(fairSupply, totalSupply.mul(confirmed).div(realBalances[i]));
}
}
if (totalSupply > 0) {
for (uint i = 0; i < amounts.length; i++) {
virtualBalancesForRemoval[_tokens[i]].scale(realBalances[i], totalSupply.add(fairSupply), totalSupply);
virtualBalancesForAddition[_tokens[i]].scale(realBalances[i], totalSupply.add(fairSupply), totalSupply);
}
}
require(fairSupply > 0, "Mooniswap: result is not enough");
_mint(msg.sender, fairSupply);
emit Deposited(msg.sender, fairSupply);
}
function withdraw(uint256 amount, uint256[] memory minReturns) external nonReentrant {
uint256 totalSupply = totalSupply();
_burn(msg.sender, amount);
for (uint i = 0; i < tokens.length; i++) {
IERC20 token = tokens[i];
uint256 preBalance = token.uniBalanceOf(address(this));
uint256 value = preBalance.mul(amount).div(totalSupply);
token.uniTransfer(msg.sender, value);
require(i >= minReturns.length || value >= minReturns[i], "Mooniswap: result is not enough");
virtualBalancesForAddition[token].scale(preBalance, totalSupply.sub(amount), totalSupply);
virtualBalancesForRemoval[token].scale(preBalance, totalSupply.sub(amount), totalSupply);
}
emit Withdrawn(msg.sender, amount);
}
function swap(IERC20 src, IERC20 dst, uint256 amount, uint256 minReturn, address referral) external payable nonReentrant returns(uint256 result) {
require(msg.value == (src.isETH() ? amount : 0), "Mooniswap: wrong value usage");
Balances memory balances = Balances({
src: src.uniBalanceOf(address(this)).sub(src.isETH() ? msg.value : 0),
dst: dst.uniBalanceOf(address(this))
});
uint256 srcAdditionBalance = Math.max(virtualBalancesForAddition[src].current(balances.src), balances.src);
uint256 dstRemovalBalance = Math.min(virtualBalancesForRemoval[dst].current(balances.dst), balances.dst);
src.uniTransferFromSenderToThis(amount);
uint256 confirmed = src.uniBalanceOf(address(this)).sub(balances.src);
result = _getReturn(src, dst, confirmed, srcAdditionBalance, dstRemovalBalance);
require(result > 0 && result >= minReturn, "Mooniswap: return is not enough");
dst.uniTransfer(msg.sender, result);
if (srcAdditionBalance != balances.src) {
virtualBalancesForAddition[src].set(srcAdditionBalance.add(confirmed));
}
if (dstRemovalBalance != balances.dst) {
virtualBalancesForRemoval[dst].set(dstRemovalBalance.sub(result));
}
virtualBalancesForRemoval[src].update(balances.src);
virtualBalancesForAddition[dst].update(balances.dst);
if (referral != address(0)) {
uint256 invariantRatio = uint256(1e36);
invariantRatio = invariantRatio.mul(balances.src.add(confirmed)).div(balances.src);
invariantRatio = invariantRatio.mul(balances.dst.sub(result)).div(balances.dst);
if (invariantRatio > 1e36) {
uint256 referralShare = invariantRatio.sqrt().sub(1e18).mul(totalSupply()).div(1e18).div(REFERRAL_SHARE);
if (referralShare > 0) {
_mint(referral, referralShare);
}
}
}
emit Swapped(msg.sender, address(src), address(dst), confirmed, result, balances.src, balances.dst, totalSupply(), referral);
volumes[src].confirmed += uint128(confirmed);
volumes[src].result += uint128(result);
}
function rescueFunds(IERC20 token, uint256 amount) external nonReentrant onlyOwner {
uint256[] memory balances = new uint256[](tokens.length);
for (uint i = 0; i < balances.length; i++) {
balances[i] = tokens[i].uniBalanceOf(address(this));
}
token.uniTransfer(msg.sender, amount);
for (uint i = 0; i < balances.length; i++) {
require(tokens[i].uniBalanceOf(address(this)) >= balances[i], "Mooniswap: access denied");
}
require(balanceOf(address(this)) >= BASE_SUPPLY, "Mooniswap: access denied");
}
function _getReturn(IERC20 src, IERC20 dst, uint256 amount, uint256 srcBalance, uint256 dstBalance) internal view returns(uint256) {
if (isToken[src] && isToken[dst] && src != dst && amount > 0) {
uint256 taxedAmount = amount.sub(amount.mul(fee()).div(FEE_DENOMINATOR));
return taxedAmount.mul(dstBalance).div(srcBalance.add(taxedAmount));
}
}
}
