// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.

// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

pragma solidity 0.5.12;
pragma experimental ABIEncoderV2;

pragma solidity ^0.5.0;

/**
 * @dev Wrappers over Solidity's arithmetic operations with added overflow
 * checks.
 *
 * Arithmetic operations in Solidity wrap on overflow. This can easily result
 * in bugs, because programmers usually assume that an overflow raises an
 * error, which is the standard behavior in high level programming languages.
 * `SafeMath` restores this intuition by reverting the transaction when an
 * operation overflows.
 *
 * Using this library instead of the unchecked operations eliminates an entire
 * class of bugs, so it's recommended to use it always.
 */
library SafeMath {
    /**
     * @dev Returns the addition of two unsigned integers, reverting on
     * overflow.
     *
     * Counterpart to Solidity's `+` operator.
     *
     * Requirements:
     * - Addition cannot overflow.
     */
    function add(uint256 a, uint256 b) internal pure returns (uint256) {
        uint256 c = a + b;
        require(c >= a, "SafeMath: addition overflow");

        return c;
    }

    /**
     * @dev Returns the subtraction of two unsigned integers, reverting on
     * overflow (when the result is negative).
     *
     * Counterpart to Solidity's `-` operator.
     *
     * Requirements:
     * - Subtraction cannot overflow.
     */
    function sub(uint256 a, uint256 b) internal pure returns (uint256) {
        return sub(a, b, "SafeMath: subtraction overflow");
    }

    /**
     * @dev Returns the subtraction of two unsigned integers, reverting with custom message on
     * overflow (when the result is negative).
     *
     * Counterpart to Solidity's `-` operator.
     *
     * Requirements:
     * - Subtraction cannot overflow.
     *
     * _Available since v2.4.0._
     */
    function sub(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        require(b <= a, errorMessage);
        uint256 c = a - b;

        return c;
    }

    /**
     * @dev Returns the multiplication of two unsigned integers, reverting on
     * overflow.
     *
     * Counterpart to Solidity's `*` operator.
     *
     * Requirements:
     * - Multiplication cannot overflow.
     */
    function mul(uint256 a, uint256 b) internal pure returns (uint256) {
        // Gas optimization: this is cheaper than requiring 'a' not being zero, but the
        // benefit is lost if 'b' is also tested.
        // See: https://github.com/OpenZeppelin/openzeppelin-contracts/pull/522
        if (a == 0) {
            return 0;
        }

        uint256 c = a * b;
        require(c / a == b, "SafeMath: multiplication overflow");

        return c;
    }

    /**
     * @dev Returns the integer division of two unsigned integers. Reverts on
     * division by zero. The result is rounded towards zero.
     *
     * Counterpart to Solidity's `/` operator. Note: this function uses a
     * `revert` opcode (which leaves remaining gas untouched) while Solidity
     * uses an invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     * - The divisor cannot be zero.
     */
    function div(uint256 a, uint256 b) internal pure returns (uint256) {
        return div(a, b, "SafeMath: division by zero");
    }

    /**
     * @dev Returns the integer division of two unsigned integers. Reverts with custom message on
     * division by zero. The result is rounded towards zero.
     *
     * Counterpart to Solidity's `/` operator. Note: this function uses a
     * `revert` opcode (which leaves remaining gas untouched) while Solidity
     * uses an invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     * - The divisor cannot be zero.
     *
     * _Available since v2.4.0._
     */
    function div(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        // Solidity only automatically asserts when dividing by 0
        require(b > 0, errorMessage);
        uint256 c = a / b;
        // assert(a == b * c + a % b); // There is no case in which this doesn't hold

        return c;
    }

    /**
     * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
     * Reverts when dividing by zero.
     *
     * Counterpart to Solidity's `%` operator. This function uses a `revert`
     * opcode (which leaves remaining gas untouched) while Solidity uses an
     * invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     * - The divisor cannot be zero.
     */
    function mod(uint256 a, uint256 b) internal pure returns (uint256) {
        return mod(a, b, "SafeMath: modulo by zero");
    }

    /**
     * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
     * Reverts with custom message when dividing by zero.
     *
     * Counterpart to Solidity's `%` operator. This function uses a `revert`
     * opcode (which leaves remaining gas untouched) while Solidity uses an
     * invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     * - The divisor cannot be zero.
     *
     * _Available since v2.4.0._
     */
    function mod(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        require(b != 0, errorMessage);
        return a % b;
    }
}

/*
 * @dev Provides information about the current execution context, including the
 * sender of the transaction and its data. While these are generally available
 * via msg.sender and msg.data, they should not be accessed in such a direct
 * manner, since when dealing with GSN meta-transactions the account sending and
 * paying for execution may not be the actual sender (as far as an application
 * is concerned).
 *
 * This contract is only required for intermediate, library-like contracts.
 */
contract Context {
    // Empty internal constructor, to prevent people from mistakenly deploying
    // an instance of this contract, which should be used via inheritance.
    constructor () internal { }
    // solhint-disable-previous-line no-empty-blocks

    function _msgSender() internal view returns (address payable) {
        return msg.sender;
    }

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

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

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

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

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

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

    /**
     * @dev Returns true if the caller is the current owner.
     */
    function isOwner() public view returns (bool) {
        return _msgSender() == _owner;
    }

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

    /**
     * @dev Transfers ownership of the contract to a new account (`newOwner`).
     * Can only be called by the current owner.
     */
    function transferOwnership(address newOwner) public onlyOwner {
        _transferOwnership(newOwner);
    }

    /**
     * @dev Transfers ownership of the contract to a new account (`newOwner`).
     */
    function _transferOwnership(address newOwner) internal {
        require(newOwner != address(0), "Ownable: new owner is the zero address");
        emit OwnershipTransferred(_owner, newOwner);
        _owner = newOwner;
    }
}

interface PoolInterface {
    function swapExactAmountIn(address, uint, address, uint, uint) external returns (uint, uint);
    function swapExactAmountOut(address, uint, address, uint, uint) external returns (uint, uint);
    function calcInGivenOut(uint, uint, uint, uint, uint, uint) external pure returns (uint);
    function calcOutGivenIn(uint, uint, uint, uint, uint, uint) external pure returns (uint);
    function getDenormalizedWeight(address) external view returns (uint);
    function getBalance(address) external view returns (uint);
    function getSwapFee() external view returns (uint);
}

interface TokenInterface {
    function balanceOf(address) external view returns (uint);
    function allowance(address, address) external view returns (uint);
    function approve(address, uint) external returns (bool);
    function transfer(address, uint) external returns (bool);
    function transferFrom(address, address, uint) external returns (bool);
    function deposit() external payable;
    function withdraw(uint) external;
}

interface RegistryInterface {
    function getBestPoolsWithLimit(address, address, uint) external view returns (address[] memory);
}

contract ExchangeProxy is Ownable {

    using SafeMath for uint256;

    struct Pool {
        address pool;
        uint    tokenBalanceIn;
        uint    tokenWeightIn;
        uint    tokenBalanceOut;
        uint    tokenWeightOut;
        uint    swapFee;
        uint    effectiveLiquidity;
    }

    struct Swap {
        address pool;
        address tokenIn;
        address tokenOut;
        uint    swapAmount; // tokenInAmount / tokenOutAmount
        uint    limitReturnAmount; // minAmountOut / maxAmountIn
        uint    maxPrice;
    }

    TokenInterface weth;
    RegistryInterface registry;
    address private constant ETH_ADDRESS = address(0xEeeeeEeeeEeEeeEeEeEeeEEEeeeeEeeeeeeeEEeE);
    uint private constant BONE = 10**18;

    constructor(address _weth) public {
        weth = TokenInterface(_weth);
    }

    function setRegistry(address _registry) external onlyOwner {
        registry = RegistryInterface(_registry);
    }

    function batchSwapExactIn(
        Swap[] memory swaps,
        TokenInterface tokenIn,
        TokenInterface tokenOut,
        uint totalAmountIn,
        uint minTotalAmountOut
    )
        public payable
        returns (uint totalAmountOut)
    {
        transferFromAll(tokenIn, totalAmountIn);

        for (uint i = 0; i < swaps.length; i++) {
            Swap memory swap = swaps[i];
            TokenInterface SwapTokenIn = TokenInterface(swap.tokenIn);
            PoolInterface pool = PoolInterface(swap.pool);

            if (SwapTokenIn.allowance(address(this), swap.pool) > 0) {
                SwapTokenIn.approve(swap.pool, 0);
            }
            SwapTokenIn.approve(swap.pool, swap.swapAmount);

            (uint tokenAmountOut,) = pool.swapExactAmountIn(
                                        swap.tokenIn,
                                        swap.swapAmount,
                                        swap.tokenOut,
                                        swap.limitReturnAmount,
                                        swap.maxPrice
                                    );
            totalAmountOut = tokenAmountOut.add(totalAmountOut);
        }

        require(totalAmountOut >= minTotalAmountOut, "ERR_LIMIT_OUT");

        transferAll(tokenOut, totalAmountOut);
        transferAll(tokenIn, getBalance(tokenIn));
    }

    function batchSwapExactOut(
        Swap[] memory swaps,
        TokenInterface tokenIn,
        TokenInterface tokenOut,
        uint maxTotalAmountIn
    )
        public payable
        returns (uint totalAmountIn)
    {
        transferFromAll(tokenIn, maxTotalAmountIn);

        for (uint i = 0; i < swaps.length; i++) {
            Swap memory swap = swaps[i];
            TokenInterface SwapTokenIn = TokenInterface(swap.tokenIn);
            PoolInterface pool = PoolInterface(swap.pool);

            if (SwapTokenIn.allowance(address(this), swap.pool) > 0) {
                SwapTokenIn.approve(swap.pool, 0);
            }
            SwapTokenIn.approve(swap.pool, swap.limitReturnAmount);

            (uint tokenAmountIn,) = pool.swapExactAmountOut(
                                        swap.tokenIn,
                                        swap.limitReturnAmount,
                                        swap.tokenOut,
                                        swap.swapAmount,
                                        swap.maxPrice
                                    );
            totalAmountIn = tokenAmountIn.add(totalAmountIn);
        }
        require(totalAmountIn <= maxTotalAmountIn, "ERR_LIMIT_IN");

        transferAll(tokenOut, getBalance(tokenOut));
        transferAll(tokenIn, getBalance(tokenIn));

    }

    function multihopBatchSwapExactIn(
        Swap[][] memory swapSequences,
        TokenInterface tokenIn,
        TokenInterface tokenOut,
        uint totalAmountIn,
        uint minTotalAmountOut
    )
        public payable
        returns (uint totalAmountOut)
    {

        transferFromAll(tokenIn, totalAmountIn);

        for (uint i = 0; i < swapSequences.length; i++) {
            uint tokenAmountOut;
            for (uint k = 0; k < swapSequences[i].length; k++) {
                Swap memory swap = swapSequences[i][k];
                TokenInterface SwapTokenIn = TokenInterface(swap.tokenIn);
                if (k == 1) {
                    // Makes sure that on the second swap the output of the first was used
                    // so there is not intermediate token leftover
                    swap.swapAmount = tokenAmountOut;
                }

                PoolInterface pool = PoolInterface(swap.pool);
                if (SwapTokenIn.allowance(address(this), swap.pool) > 0) {
                    SwapTokenIn.approve(swap.pool, 0);
                }
                SwapTokenIn.approve(swap.pool, swap.swapAmount);
                (tokenAmountOut,) = pool.swapExactAmountIn(
                                            swap.tokenIn,
                                            swap.swapAmount,
                                            swap.tokenOut,
                                            swap.limitReturnAmount,
                                            swap.maxPrice
                                        );
            }
            // This takes the amountOut of the last swap
            totalAmountOut = tokenAmountOut.add(totalAmountOut);
        }

        require(totalAmountOut >= minTotalAmountOut, "ERR_LIMIT_OUT");

        transferAll(tokenOut, totalAmountOut);
        transferAll(tokenIn, getBalance(tokenIn));

    }

    function multihopBatchSwapExactOut(
        Swap[][] memory swapSequences,
        TokenInterface tokenIn,
        TokenInterface tokenOut,
        uint maxTotalAmountIn
    )
        public payable
        returns (uint totalAmountIn)
    {

        transferFromAll(tokenIn, maxTotalAmountIn);

        for (uint i = 0; i < swapSequences.length; i++) {
            uint tokenAmountInFirstSwap;
            // Specific code for a simple swap and a multihop (2 swaps in sequence)
            if (swapSequences[i].length == 1) {
                Swap memory swap = swapSequences[i][0];
                TokenInterface SwapTokenIn = TokenInterface(swap.tokenIn);

                PoolInterface pool = PoolInterface(swap.pool);
                if (SwapTokenIn.allowance(address(this), swap.pool) > 0) {
                    SwapTokenIn.approve(swap.pool, 0);
                }
                SwapTokenIn.approve(swap.pool, swap.limitReturnAmount);

                (tokenAmountInFirstSwap,) = pool.swapExactAmountOut(
                                        swap.tokenIn,
                                        swap.limitReturnAmount,
                                        swap.tokenOut,
                                        swap.swapAmount,
                                        swap.maxPrice
                                    );
            } else {
                // Consider we are swapping A -> B and B -> C. The goal is to buy a given amount
                // of token C. But first we need to buy B with A so we can then buy C with B
                // To get the exact amount of C we then first need to calculate how much B we'll need:
                uint intermediateTokenAmount; // This would be token B as described above
                Swap memory secondSwap = swapSequences[i][1];
                PoolInterface poolSecondSwap = PoolInterface(secondSwap.pool);
                intermediateTokenAmount = poolSecondSwap.calcInGivenOut(
                                        poolSecondSwap.getBalance(secondSwap.tokenIn),
                                        poolSecondSwap.getDenormalizedWeight(secondSwap.tokenIn),
                                        poolSecondSwap.getBalance(secondSwap.tokenOut),
                                        poolSecondSwap.getDenormalizedWeight(secondSwap.tokenOut),
                                        secondSwap.swapAmount,
                                        poolSecondSwap.getSwapFee()
                                    );

                //// Buy intermediateTokenAmount of token B with A in the first pool
                Swap memory firstSwap = swapSequences[i][0];
                TokenInterface FirstSwapTokenIn = TokenInterface(firstSwap.tokenIn);
                PoolInterface poolFirstSwap = PoolInterface(firstSwap.pool);
                if (FirstSwapTokenIn.allowance(address(this), firstSwap.pool) < uint(-1)) {
                    FirstSwapTokenIn.approve(firstSwap.pool, uint(-1));
                }

                (tokenAmountInFirstSwap,) = poolFirstSwap.swapExactAmountOut(
                                        firstSwap.tokenIn,
                                        firstSwap.limitReturnAmount,
                                        firstSwap.tokenOut,
                                        intermediateTokenAmount, // This is the amount of token B we need
                                        firstSwap.maxPrice
                                    );

                //// Buy the final amount of token C desired
                TokenInterface SecondSwapTokenIn = TokenInterface(secondSwap.tokenIn);
                if (SecondSwapTokenIn.allowance(address(this), secondSwap.pool) < uint(-1)) {
                    SecondSwapTokenIn.approve(secondSwap.pool, uint(-1));
                }

                poolSecondSwap.swapExactAmountOut(
                                        secondSwap.tokenIn,
                                        secondSwap.limitReturnAmount,
                                        secondSwap.tokenOut,
                                        secondSwap.swapAmount,
                                        secondSwap.maxPrice
                                    );
            }
            totalAmountIn = tokenAmountInFirstSwap.add(totalAmountIn);
        }

        require(totalAmountIn <= maxTotalAmountIn, "ERR_LIMIT_IN");

        transferAll(tokenOut, getBalance(tokenOut));
        transferAll(tokenIn, getBalance(tokenIn));

    }

    function smartSwapExactIn(
        TokenInterface tokenIn,
        TokenInterface tokenOut,
        uint totalAmountIn,
        uint minTotalAmountOut,
        uint nPools
    )
        public payable
        returns (uint totalAmountOut)
    {
        Swap[] memory swaps;
        if (isETH(tokenIn)) {
          (swaps,) = viewSplitExactIn(address(weth), address(tokenOut), totalAmountIn, nPools);
        } else if (isETH(tokenOut)){
          (swaps,) = viewSplitExactIn(address(tokenIn), address(weth), totalAmountIn, nPools);
        } else {
          (swaps,) = viewSplitExactIn(address(tokenIn), address(tokenOut), totalAmountIn, nPools);
        }

        totalAmountOut = batchSwapExactIn(swaps, tokenIn, tokenOut, totalAmountIn, minTotalAmountOut);
    }

    function smartSwapExactOut(
        TokenInterface tokenIn,
        TokenInterface tokenOut,
        uint totalAmountOut,
        uint maxTotalAmountIn,
        uint nPools
    )
        public payable
        returns (uint totalAmountIn)
    {
        Swap[] memory swaps;
        if (isETH(tokenIn)) {
          (swaps,) = viewSplitExactOut(address(weth), address(tokenOut), totalAmountOut, nPools);
        } else if (isETH(tokenOut)){
          (swaps,) = viewSplitExactOut(address(tokenIn), address(weth), totalAmountOut, nPools);
        } else {
          (swaps,) = viewSplitExactOut(address(tokenIn), address(tokenOut), totalAmountOut, nPools);
        }

        totalAmountIn = batchSwapExactOut(swaps, tokenIn, tokenOut, maxTotalAmountIn);
    }

    function viewSplitExactIn(
        address tokenIn,
        address tokenOut,
        uint swapAmount,
        uint nPools
    )
        public view
        returns (Swap[] memory swaps, uint totalOutput)
    {
        address[] memory poolAddresses = registry.getBestPoolsWithLimit(tokenIn, tokenOut, nPools);

        Pool[] memory pools = new Pool[](poolAddresses.length);
        uint sumEffectiveLiquidity;
        for (uint i = 0; i < poolAddresses.length; i++) {
            pools[i] = getPoolData(tokenIn, tokenOut, poolAddresses[i]);
            sumEffectiveLiquidity = sumEffectiveLiquidity.add(pools[i].effectiveLiquidity);
        }

        uint[] memory bestInputAmounts = new uint[](pools.length);
        uint totalInputAmount;
        for (uint i = 0; i < pools.length; i++) {
            bestInputAmounts[i] = swapAmount.mul(pools[i].effectiveLiquidity).div(sumEffectiveLiquidity);
            totalInputAmount = totalInputAmount.add(bestInputAmounts[i]);
        }

        if (totalInputAmount < swapAmount) {
            bestInputAmounts[0] = bestInputAmounts[0].add(swapAmount.sub(totalInputAmount));
        } else {
            bestInputAmounts[0] = bestInputAmounts[0].sub(totalInputAmount.sub(swapAmount));
        }

        swaps = new Swap[](pools.length);

        for (uint i = 0; i < pools.length; i++) {
            swaps[i] = Swap({
                        pool: pools[i].pool,
                        tokenIn: tokenIn,
                        tokenOut: tokenOut,
                        swapAmount: bestInputAmounts[i],
                        limitReturnAmount: 0,
                        maxPrice: uint(-1)
                    });
        }

        totalOutput = calcTotalOutExactIn(bestInputAmounts, pools);

        return (swaps, totalOutput);
    }

    function viewSplitExactOut(
        address tokenIn,
        address tokenOut,
        uint swapAmount,
        uint nPools
    )
        public view
        returns (Swap[] memory swaps, uint totalOutput)
    {
        address[] memory poolAddresses = registry.getBestPoolsWithLimit(tokenIn, tokenOut, nPools);

        Pool[] memory pools = new Pool[](poolAddresses.length);
        uint sumEffectiveLiquidity;
        for (uint i = 0; i < poolAddresses.length; i++) {
            pools[i] = getPoolData(tokenIn, tokenOut, poolAddresses[i]);
            sumEffectiveLiquidity = sumEffectiveLiquidity.add(pools[i].effectiveLiquidity);
        }

        uint[] memory bestInputAmounts = new uint[](pools.length);
        uint totalInputAmount;
        for (uint i = 0; i < pools.length; i++) {
            bestInputAmounts[i] = swapAmount.mul(pools[i].effectiveLiquidity).div(sumEffectiveLiquidity);
            totalInputAmount = totalInputAmount.add(bestInputAmounts[i]);
        }
        
         if (totalInputAmount < swapAmount) {
            bestInputAmounts[0] = bestInputAmounts[0].add(swapAmount.sub(totalInputAmount));
        } else {
            bestInputAmounts[0] = bestInputAmounts[0].sub(totalInputAmount.sub(swapAmount));
        }

        swaps = new Swap[](pools.length);

        for (uint i = 0; i < pools.length; i++) {
            swaps[i] = Swap({
                        pool: pools[i].pool,
                        tokenIn: tokenIn,
                        tokenOut: tokenOut,
                        swapAmount: bestInputAmounts[i],
                        limitReturnAmount: uint(-1),
                        maxPrice: uint(-1)
                    });
        }

        totalOutput = calcTotalOutExactOut(bestInputAmounts, pools);

        return (swaps, totalOutput);
    }

    function getPoolData(
        address tokenIn,
        address tokenOut,
        address poolAddress
    )
        internal view
        returns (Pool memory)
    {
        PoolInterface pool = PoolInterface(poolAddress);
        uint tokenBalanceIn = pool.getBalance(tokenIn);
        uint tokenBalanceOut = pool.getBalance(tokenOut);
        uint tokenWeightIn = pool.getDenormalizedWeight(tokenIn);
        uint tokenWeightOut = pool.getDenormalizedWeight(tokenOut);
        uint swapFee = pool.getSwapFee();

        uint effectiveLiquidity = calcEffectiveLiquidity(
                                            tokenWeightIn,
                                            tokenBalanceOut,
                                            tokenWeightOut
                                        );
        Pool memory returnPool = Pool({
            pool: poolAddress,
            tokenBalanceIn: tokenBalanceIn,
            tokenWeightIn: tokenWeightIn,
            tokenBalanceOut: tokenBalanceOut,
            tokenWeightOut: tokenWeightOut,
            swapFee: swapFee,
            effectiveLiquidity: effectiveLiquidity
        });

        return returnPool;
    }

    function calcEffectiveLiquidity(
        uint tokenWeightIn,
        uint tokenBalanceOut,
        uint tokenWeightOut
    )
        internal pure
        returns (uint effectiveLiquidity)
    {

        // Bo * wi/(wi+wo)
        effectiveLiquidity = 
            tokenWeightIn.mul(BONE).div(
                tokenWeightOut.add(tokenWeightIn)
            ).mul(tokenBalanceOut).div(BONE);

        return effectiveLiquidity;
    }

    function calcTotalOutExactIn(
        uint[] memory bestInputAmounts,
        Pool[] memory bestPools
    )
        internal pure
        returns (uint totalOutput)
    {
        totalOutput = 0;
        for (uint i = 0; i < bestInputAmounts.length; i++) {
            uint output = PoolInterface(bestPools[i].pool).calcOutGivenIn(
                                bestPools[i].tokenBalanceIn,
                                bestPools[i].tokenWeightIn,
                                bestPools[i].tokenBalanceOut,
                                bestPools[i].tokenWeightOut,
                                bestInputAmounts[i],
                                bestPools[i].swapFee
                            );

            totalOutput = totalOutput.add(output);
        }
        return totalOutput;
    }

    function calcTotalOutExactOut(
        uint[] memory bestInputAmounts,
        Pool[] memory bestPools
    )
        internal pure
        returns (uint totalOutput)
    {
        totalOutput = 0;
        for (uint i = 0; i < bestInputAmounts.length; i++) {
            uint output = PoolInterface(bestPools[i].pool).calcInGivenOut(
                                bestPools[i].tokenBalanceIn,
                                bestPools[i].tokenWeightIn,
                                bestPools[i].tokenBalanceOut,
                                bestPools[i].tokenWeightOut,
                                bestInputAmounts[i],
                                bestPools[i].swapFee
                            );

            totalOutput = totalOutput.add(output);
        }
        return totalOutput;
    }

    function transferFromAll(TokenInterface token, uint amount) internal returns(bool) {
        if (isETH(token)) {
            weth.deposit.value(msg.value)();
        } else {
            require(token.transferFrom(msg.sender, address(this), amount), "ERR_TRANSFER_FAILED");
        }
    }

    function getBalance(TokenInterface token) internal view returns (uint) {
        if (isETH(token)) {
            return weth.balanceOf(address(this));
        } else {
            return token.balanceOf(address(this));
        }
    }

    function transferAll(TokenInterface token, uint amount) internal returns(bool) {
        if (amount == 0) {
            return true;
        }

        if (isETH(token)) {
            weth.withdraw(amount);
            (bool xfer,) = msg.sender.call.value(amount)("");
            require(xfer, "ERR_ETH_FAILED");
        } else {
            require(token.transfer(msg.sender, amount), "ERR_TRANSFER_FAILED");
        }
    }

    function isETH(TokenInterface token) internal pure returns(bool) {
        return (address(token) == ETH_ADDRESS);
    }

    function() external payable {}
}

pragma solidity 0.5.16;

library SafeMath {

    function mul(uint256 a, uint256 b) internal pure returns (uint256) {
        if (a == 0) 
            return 0;
        uint256 c = a * b;
        require(c / a == b);
        return c;
    }

    function div(uint256 a, uint256 b) internal pure returns (uint256) {
        require(b > 0);
        uint256 c = a / b;
        return c;
    }

    function divCeil(uint256 a, uint256 b) internal pure returns (uint256) {
        require(b > 0);
        uint256 c = a / b;
        if(a % b != 0)
            c = c + 1;
        return c;
    }

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

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

    function mod(uint256 a, uint256 b) internal pure returns (uint256) {
        require(b != 0);
        return a % b;
    }

    int256 constant private INT256_MIN = -2^255;

    function mul(int256 a, int256 b) internal pure returns (int256) {
        if (a == 0) 
            return 0;
        int256 c = a * b;
        require(c / a == b && (a != -1 || b != INT256_MIN));
        return c;
    }

    function div(int256 a, int256 b) internal pure returns (int256) {
        require(b != 0 && (b != -1 || a != INT256_MIN));
        int256 c = a / b;
        return c;
    }

    function sub(int256 a, int256 b) internal pure returns (int256) {
        int256 c = a - b;
        require((b >= 0 && c <= a) || (b < 0 && c > a));
        return c;
    }

    function add(int256 a, int256 b) internal pure returns (int256) {
        int256 c = a + b;
        require((b >= 0 && c >= a) || (b < 0 && c < a));
        return c;
    }

    function sqrt(int256 x) internal pure returns (int256) {
        int256 z = add(x / 2, 1);
        int256 y = x;
        while (z < y)
        {
            y = z;
            z = ((add((x / z), z)) / 2);
        }
        return y;
    }
}


contract ERC20 {
    using SafeMath for uint256;

    mapping (address => uint256) internal _balances;
    mapping (address => mapping (address => uint256)) internal _allowed;
    
    event Transfer(address indexed from, address indexed to, uint256 value);
    event Approval(address indexed owner, address indexed spender, uint256 value);

    uint256 internal _totalSupply;

    /**
    * @dev Total number of tokens in existence
    */
    function totalSupply() public view returns (uint256) {
        return _totalSupply;
    }

    /**
    * @dev Gets the balance of the specified address.
    * @param owner The address to query the balance of.
    * @return A uint256 representing the amount owned by the passed address.
    */
    function balanceOf(address owner) public view returns (uint256) {
        return _balances[owner];
    }

    /**
    * @dev Function to check the amount of tokens that an owner allowed to a spender.
    * @param owner address The address which owns the funds.
    * @param spender address The address which will spend the funds.
    * @return A uint256 specifying the amount of tokens still available for the spender.
    */
    function allowance(address owner, address spender) public view returns (uint256) {
        return _allowed[owner][spender];
    }

    /**
    * @dev Transfer token to a specified address
    * @param to The address to transfer to.
    * @param value The amount to be transferred.
    */
    function transfer(address to, uint256 value) public returns (bool) {
        _transfer(msg.sender, to, value);
        return true;
    }

    /**
    * @dev Approve the passed address to spend the specified amount of tokens on behalf of msg.sender.
    * 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
    * @param spender The address which will spend the funds.
    * @param value The amount of tokens to be spent.
    */
    function approve(address spender, uint256 value) public returns (bool) {
        _allowed[msg.sender][spender] = value;
        emit Approval(msg.sender, spender, value);
        return true;
    }

    /**
    * @dev Transfer tokens from one address to another.
    * Note that while this function emits an Approval event, this is not required as per the specification,
    * and other compliant implementations may not emit the event.
    * @param from address The address which you want to send tokens from
    * @param to address The address which you want to transfer to
    * @param value uint256 the amount of tokens to be transferred
    */
    function transferFrom(address from, address to, uint256 value) public returns (bool) {
        _allowed[from][msg.sender] = _allowed[from][msg.sender].sub(value);
        _transfer(from, to, value);
        return true;
    }

    function _transfer(address from, address to, uint256 value) internal {
        require(to != address(0));
        _balances[from] = _balances[from].sub(value);
        _balances[to] = _balances[to].add(value);
        emit Transfer(from, to, value);
    }

}

contract ERC20Mintable is ERC20 {
    string public name;
    string public symbol;
    uint8 public decimals;

    function _mint(address to, uint256 amount) internal {
        _balances[to] = _balances[to].add(amount);
        _totalSupply = _totalSupply.add(amount);
        emit Transfer(address(0), to, amount);
    }

    function _burn(address from, uint256 amount) internal {
        _balances[from] = _balances[from].sub(amount);
        _totalSupply = _totalSupply.sub(amount);
        emit Transfer(from, address(0), amount);
    }
}

contract CERC20 is ERC20 {
    function borrow(uint256) external returns (uint256);
    function borrowBalanceCurrent(address) external returns (uint256);
    function repayBorrow(uint256) external returns (uint256);
    function mint(uint256) external returns (uint256);
    function redeemUnderlying(uint256) external returns (uint256);
    function balanceOfUnderlying(address) external returns (uint256);
}


interface Comptroller {
    function enterMarkets(address[] calldata) external returns (uint256[] memory);
}

contract UniswapV2Router02 {
    function swapExactTokensForTokens(uint amountIn, uint amountOutMin, address[] calldata path, address to, uint deadline) external returns (uint[] memory amounts);
}

contract blackholeswap is ERC20Mintable {
    using SafeMath for *;

    /***********************************|
    |        Variables && Events        |
    |__________________________________*/

    Comptroller constant comptroller = Comptroller(0x3d9819210A31b4961b30EF54bE2aeD79B9c9Cd3B);
    UniswapV2Router02 constant uniswap = UniswapV2Router02(0x7a250d5630B4cF539739dF2C5dAcb4c659F2488D);

    ERC20 constant Comp = ERC20(0xc00e94Cb662C3520282E6f5717214004A7f26888);
    ERC20 constant Dai = ERC20(0x6B175474E89094C44Da98b954EedeAC495271d0F);
    ERC20 constant USDC = ERC20(0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48);
    CERC20 constant cDai = CERC20(0x5d3a536E4D6DbD6114cc1Ead35777bAB948E3643);
    CERC20 constant cUSDC = CERC20(0x39AA39c021dfbaE8faC545936693aC917d5E7563);

    event Purchases(address indexed buyer, address indexed sell_token, uint256 inputs, address indexed buy_token, uint256 outputs);
    event AddLiquidity(address indexed provider, uint256 share, int256 DAIAmount, int256 USDCAmount);
    event RemoveLiquidity(address indexed provider, uint256 share, int256 DAIAmount, int256 USDCAmount);

    /***********************************|
    |            Constsructor           |
    |__________________________________*/

    constructor() public {
        symbol = "BHSc$";
        name = "BlackHoleSwap-Compound DAI/USDC v1";
        decimals = 18;

        Dai.approve(address(cDai), uint256(-1));
        USDC.approve(address(cUSDC), uint256(-1));
        Comp.approve(address(uniswap), uint256(-1));

        address[] memory cTokens = new address[](2);
        cTokens[0] = address(cDai);
        cTokens[1] = address(cUSDC);
        uint256[] memory errors = comptroller.enterMarkets(cTokens);
        require(errors[0] == 0 && errors[1] == 0, "Comptroller.enterMarkets failed.");

        admin = msg.sender;
    }

    /***********************************|
    |        Governmence & Params       |
    |__________________________________*/

    uint256 public fee = 0.99985e18;
    uint256 public protocolFee = 0;
    uint256 public constant amplifier = 0.75e18;

    address private admin;
    address private vault;

    function setAdmin(address _admin) external {
        require(msg.sender == admin);
        admin = _admin;
    }

    function setParams(uint256 _fee, uint256 _protocolFee) external {
        require(msg.sender == admin);
        require(_fee < 1e18 && _fee >= 0.99e18); //0 < fee <= 1%
        if(_protocolFee > 0)
            require(uint256(1e18).sub(_fee).div(_protocolFee) >= 3); //protocolFee < 33.3% fee
        fee = _fee;
        protocolFee = _protocolFee;
    }

    function setVault(address _vault) external {
        require(msg.sender == admin);
        vault = _vault;
    }

    /***********************************|
    |         Getter Functions          |
    |__________________________________*/

    function getDaiBalance() public returns (uint256, uint256) {
        if (cDai.balanceOf(address(this)) <= 10)
            return (0, cDai.borrowBalanceCurrent(address(this)));
        else
            return (cDai.balanceOfUnderlying(address(this)), cDai.borrowBalanceCurrent(address(this)));
    }

    function getUSDCBalance() public returns (uint256, uint256) {
        if (cUSDC.balanceOf(address(this)) <= 10)
            return (0, cUSDC.borrowBalanceCurrent(address(this)).mul(rate()) );
        else
            return (cUSDC.balanceOfUnderlying(address(this)).mul(rate()), cUSDC.borrowBalanceCurrent(address(this)).mul(rate()));
    }

    // DAI + USDC
    function S() external returns (uint256) {
        (uint256 a, uint256 b) = getDaiBalance();
        (uint256 c, uint256 d) = getUSDCBalance();
        return(a.add(c).sub(b).sub(d));
    }

    function F(int256 _x, int256 x, int256 y) internal pure returns (int256 _y) {
        int256 k;
        int256 c;
        {
            // u = x + ay, v = y + ax
            int256 u = x.add(y.mul(int256(amplifier)).div(1e18));
            int256 v = y.add(x.mul(int256(amplifier)).div(1e18));
            k = u.mul(v); // k = u * v
            c = _x.mul(_x).sub( k.mul(1e18).div(int256(amplifier)) ); // c = x^2 - k/a
        }
        
        int256 cst = int256(amplifier).add(1e36.div(int256(amplifier))); // a + 1/a
        int256 b = _x.mul(cst).div(1e18); 

        // y^2 + by + c = 0
        // D = b^2 - 4c
        // _y = (-b + sqrt(D)) / 2

        int256 D = b.mul(b).sub(c.mul(4));

        require(D >= 0, "no root");

        _y = (-b).add(D.sqrt()).div(2);

    }

    function getInputPrice(uint256 input, uint256 a, uint256 b, uint256 c, uint256 d) public pure returns (uint256) {
        int256 x = int256(a).sub(int256(b));
        int256 y = int256(c).sub(int256(d));
        int256 _x = x.add(int256(input));

        int256 _y = F(_x, x, y);

        return uint256(y.sub(_y));
    }

    function getOutputPrice(uint256 output, uint256 a, uint256 b, uint256 c, uint256 d) public pure returns (uint256) {
        int256 x = int256(a).sub(int256(b));
        int256 y = int256(c).sub(int256(d));
        int256 _y = y.sub(int256(output));

        int256 _x = F(_y, y, x);

        return uint256(_x.sub(x));
    }

    function rate() public pure returns (uint256) {
        return 1e12;
    }

    /***********************************|
    |        Exchange Functions         |
    |__________________________________*/
    
    function calcFee(uint256 input, uint256 a, uint256 b, uint256 c, uint256 d) internal {
        if(protocolFee > 0) {
            uint256 _fee = input.mul(protocolFee).mul(_totalSupply).div(1e18).div( a.add(c).sub(b).sub(d) );
            _mint(vault, _fee);
        }
    }

    function dai2usdcIn(uint256 input, uint256 min_output, uint256 deadline) external returns (uint256) {
        require(block.timestamp <= deadline, "EXPIRED");
        (uint256 a, uint256 b) = getDaiBalance();
        (uint256 c, uint256 d) = getUSDCBalance();

        uint256 output = getInputPrice(input.mul(fee).div(1e18), a, b, c, d);
        securityCheck(input, output, a, b, c, d);
        output = output.div(rate());
        require(output >= min_output, "SLIPPAGE_DETECTED");

        calcFee(input, a, b, c, d);

        doTransferIn(Dai, cDai, b, msg.sender, input);
        doTransferOut(USDC, cUSDC, c.div(rate()), msg.sender, output);

        emit Purchases(msg.sender, address(Dai), input, address(USDC), output);

        return output;
    }
    
    function usdc2daiIn(uint256 input, uint256 min_output, uint256 deadline) external returns (uint256) {
        require(block.timestamp <= deadline, "EXPIRED");
        (uint256 a, uint256 b) = getDaiBalance();
        (uint256 c, uint256 d) = getUSDCBalance();

        uint256 output = getInputPrice(input.mul(fee).div(1e6), c, d, a, b); // input * rate() * fee / 1e18
        securityCheck(input.mul(rate()), output, c, d, a, b);
        require(output >= min_output, "SLIPPAGE_DETECTED");
        
        calcFee(input.mul(rate()), a, b, c, d);
        
        doTransferIn(USDC, cUSDC, d.div(rate()), msg.sender, input);
        doTransferOut(Dai, cDai, a, msg.sender, output);

        emit Purchases(msg.sender, address(USDC), input, address(Dai), output);

        return output;
    }

    function dai2usdcOut(uint256 max_input, uint256 output, uint256 deadline) external returns (uint256) {
        require(block.timestamp <= deadline, "EXPIRED");
        (uint256 a, uint256 b) = getDaiBalance();
        (uint256 c, uint256 d) = getUSDCBalance();

        uint256 input = getOutputPrice(output.mul(rate()), a, b, c, d);
        securityCheck(input, output.mul(rate()), a, b, c, d);
        input = input.mul(1e18).divCeil(fee);
        require(input <= max_input, "SLIPPAGE_DETECTED");

        calcFee(input, a, b, c, d);

        doTransferIn(Dai, cDai, b, msg.sender, input);
        doTransferOut(USDC, cUSDC, c.div(rate()), msg.sender, output);

        emit Purchases(msg.sender, address(Dai), input, address(USDC), output);

        return input;
    }
    
    function usdc2daiOut(uint256 max_input, uint256 output, uint256 deadline) external returns (uint256) {
        require(block.timestamp <= deadline, "EXPIRED");
        (uint256 a, uint256 b) = getDaiBalance();
        (uint256 c, uint256 d) = getUSDCBalance();

        uint256 input = getOutputPrice(output, c, d, a, b);
        securityCheck(input, output, c, d, a, b);
        input = input.mul(1e6).divCeil(fee); // input * 1e18 / fee / 1e12
        require(input <= max_input, "SLIPPAGE_DETECTED");

        calcFee(input.mul(rate()), a, b, c, d);

        doTransferIn(USDC, cUSDC, d.div(rate()), msg.sender, input);
        doTransferOut(Dai, cDai, a, msg.sender, output);

        emit Purchases(msg.sender, address(USDC), input, address(Dai), output);

        return input;
    }
    
    function doTransferIn(ERC20 token, CERC20 ctoken, uint256 debt, address from, uint256 amount) internal {
        require(token.transferFrom(from, address(this), amount));

        if(debt > 0) {
            if(debt >= amount) {
                require(ctoken.repayBorrow(amount) == 0, "ctoken.repayBorrow failed");
            }
            else {
                require(ctoken.repayBorrow(debt) == 0, "ctoken.repayBorrow failed");
                require(ctoken.mint(amount.sub(debt)) == 0, "ctoken.mint failed");
            }
        }
        else {
            require(ctoken.mint(amount) == 0, "ctoken.mint failed");
        }
    }

    function doTransferOut(ERC20 token, CERC20 ctoken, uint256 balance, address to, uint256 amount) internal {
        if(balance >= amount) {
            require(ctoken.redeemUnderlying(amount) == 0, "ctoken.redeemUnderlying failed");
        }
        else {
            if(balance == 0) {
                require(ctoken.borrow(amount) == 0, "ctoken.borrow failed");
            }
            else {
                require(ctoken.redeemUnderlying(balance) == 0, "ctoken.redeemUnderlying failed");
                require(ctoken.borrow(amount.sub(balance)) == 0, "ctoken.borrow failed");
            }
        }

        require(token.transfer(to, amount));
    }

    function securityCheck(uint256 input, uint256 output, uint256 a, uint256 b, uint256 c, uint256 d) internal pure {
        if(c < output.add(d))
            require(output.add(d).sub(c).mul(100) < input.add(a).sub(b).mul(62), "DEBT_TOO_MUCH"); // debt/collateral < 62%
    }

    /***********************************|
    |        Liquidity Functions        |
    |__________________________________*/

    function addLiquidity(uint256 share, uint256[4] calldata tokens) external returns (uint256 dai_in, uint256 dai_out, uint256 usdc_in, uint256 usdc_out) {
        require(share >= 1e15, 'INVALID_ARGUMENT'); // 1000 * rate()

        collectComp();

        if (_totalSupply > 0) {
            (uint256 a, uint256 b) = getDaiBalance();
            (uint256 c, uint256 d) = getUSDCBalance();

            dai_in = share.mul(a).divCeil(_totalSupply);
            dai_out = share.mul(b).div(_totalSupply);
            usdc_in = share.mul(c).divCeil(_totalSupply.mul(rate()));
            usdc_out = share.mul(d).div(_totalSupply.mul(rate()));
            require(dai_in <= tokens[0] && dai_out >= tokens[1] && usdc_in <= tokens[2] && usdc_out >= tokens[3], "SLIPPAGE_DETECTED");
            
            _mint(msg.sender, share);

            if(dai_in > 0)
                doTransferIn(Dai, cDai, b, msg.sender, dai_in);
            if(usdc_in > 0)
                doTransferIn(USDC, cUSDC, d.div(rate()), msg.sender, usdc_in);
            if(dai_out > 0)
                doTransferOut(Dai, cDai, a, msg.sender, dai_out);
            if(usdc_out > 0)
                doTransferOut(USDC, cUSDC, c.div(rate()), msg.sender, usdc_out);

            int256 dai_amount = int256(dai_in).sub(int256(dai_out));
            int256 usdc_amount = int256(usdc_in).sub(int256(usdc_out));

            emit AddLiquidity(msg.sender, share, dai_amount, usdc_amount);
            return (dai_in, dai_out, usdc_in, usdc_out);
        } else {
            uint256 dai_amount = share.divCeil(2);
            uint256 usdc_amount = share.divCeil(rate().mul(2));

            _mint(msg.sender, share);
            doTransferIn(Dai, cDai, 0, msg.sender, dai_amount);
            doTransferIn(USDC, cUSDC, 0, msg.sender, usdc_amount);
            
            emit AddLiquidity(msg.sender, share, int256(dai_amount), int256(usdc_amount));
            return (dai_amount, 0, usdc_amount, 0);
        }
    }

    function removeLiquidity(uint256 share, uint256[4] calldata tokens) external returns (uint256 dai_in, uint256 dai_out, uint256 usdc_in, uint256 usdc_out) {
        require(share > 0, 'INVALID_ARGUMENT');

        collectComp();

        (uint256 a, uint256 b) = getDaiBalance();
        (uint256 c, uint256 d) = getUSDCBalance();

        dai_out = share.mul(a).div(_totalSupply);
        dai_in = share.mul(b).divCeil(_totalSupply);
        usdc_out = share.mul(c).div(_totalSupply.mul(rate()));
        usdc_in = share.mul(d).divCeil(_totalSupply.mul(rate()));
        require(dai_in <= tokens[0] && dai_out >= tokens[1] && usdc_in <= tokens[2] && usdc_out >= tokens[3], "SLIPPAGE_DETECTED");

        _burn(msg.sender, share);

        if(dai_in > 0)
            doTransferIn(Dai, cDai, b, msg.sender, dai_in);
        if(usdc_in > 0)
            doTransferIn(USDC, cUSDC, d.div(rate()), msg.sender, usdc_in);
        if(dai_out > 0)
            doTransferOut(Dai, cDai, a, msg.sender, dai_out);
        if(usdc_out > 0)
            doTransferOut(USDC, cUSDC, c.div(rate()), msg.sender, usdc_out);

        int256 dai_amount = int256(dai_out).sub(int256(dai_in));
        int256 usdc_amount = int256(usdc_out).sub(int256(usdc_in));

        emit RemoveLiquidity(msg.sender, share, dai_amount, usdc_amount);

        return(dai_in, dai_out, usdc_in, usdc_out);
    }

    /***********************************|
    |           Collect Comp            |
    |__________________________________*/

    function collectComp() public {
        uint256 _comp = Comp.balanceOf(address(this));
        if(_comp == 0) return;

        (uint256 a, uint256 b) = getDaiBalance();
        (uint256 c, uint256 d) = getUSDCBalance();

        bool isDai = a.add(d) > c.add(b);

        address[] memory path = new address[](3);
        path[0] = address(Comp);
        path[1] = 0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2; //weth
        path[2] = isDai ? address(Dai) : address(USDC);
        uint256[] memory amounts = uniswap.swapExactTokensForTokens(_comp, 0, path, address(this), now);

        if(isDai)
            require(cDai.mint(amounts[2]) == 0, "ctoken.mint failed");
        else
            require(cUSDC.mint(amounts[2]) == 0, "ctoken.mint failed");

    }

}

{"BColor.sol":{"content":"// This program is free software: you can redistribute it and/or modify\n// it under the terms of the GNU General Public License as published by\n// the Free Software Foundation, either version 3 of the License, or\n// (at your option) any later version.\n\n// This program is distributed in the hope that it will be useful,\n// but WITHOUT ANY WARRANTY; without even the implied warranty of\n// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the\n// GNU General Public License for more details.\n\n// You should have received a copy of the GNU General Public License\n// along with this program.  If not, see \u003chttp://www.gnu.org/licenses/\u003e.\n\npragma solidity 0.5.12;\n\ncontract BColor {\n    function getColor()\n        external view\n        returns (bytes32);\n}\n\ncontract BBronze is BColor {\n    function getColor()\n        external view\n        returns (bytes32) {\n            return bytes32(\"BRONZE\");\n        }\n}\n"},"BConst.sol":{"content":"// This program is free software: you can redistribute it and/or modify\n// it under the terms of the GNU General Public License as published by\n// the Free Software Foundation, either version 3 of the License, or\n// (at your option) any later version.\n\n// This program is distributed in the hope that it will be useful,\n// but WITHOUT ANY WARRANTY; without even the implied warranty of\n// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the\n// GNU General Public License for more details.\n\n// You should have received a copy of the GNU General Public License\n// along with this program.  If not, see \u003chttp://www.gnu.org/licenses/\u003e.\n\npragma solidity 0.5.12;\n\nimport \"./BColor.sol\";\n\ncontract BConst is BBronze {\n    uint public constant BONE              = 10**18;\n\n    uint public constant MIN_BOUND_TOKENS  = 2;\n    uint public constant MAX_BOUND_TOKENS  = 8;\n\n    uint public constant MIN_FEE           = BONE / 10**6;\n    uint public constant MAX_FEE           = BONE / 10;\n    uint public constant EXIT_FEE          = 0;\n\n    uint public constant MIN_WEIGHT        = BONE;\n    uint public constant MAX_WEIGHT        = BONE * 50;\n    uint public constant MAX_TOTAL_WEIGHT  = BONE * 50;\n    uint public constant MIN_BALANCE       = BONE / 10**12;\n\n    uint public constant INIT_POOL_SUPPLY  = BONE * 100;\n\n    uint public constant MIN_BPOW_BASE     = 1 wei;\n    uint public constant MAX_BPOW_BASE     = (2 * BONE) - 1 wei;\n    uint public constant BPOW_PRECISION    = BONE / 10**10;\n\n    uint public constant MAX_IN_RATIO      = BONE / 2;\n    uint public constant MAX_OUT_RATIO     = (BONE / 3) + 1 wei;\n}\n"},"BMath.sol":{"content":"// This program is free software: you can redistribute it and/or modify\n// it under the terms of the GNU General Public License as published by\n// the Free Software Foundation, either version 3 of the License, or\n// (at your option) any later version.\n\n// This program is distributed in the hope that it will be useful,\n// but WITHOUT ANY WARRANTY; without even the implied warranty of\n// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the\n// GNU General Public License for more details.\n\n// You should have received a copy of the GNU General Public License\n// along with this program.  If not, see \u003chttp://www.gnu.org/licenses/\u003e.\n\npragma solidity 0.5.12;\n\nimport \"./BNum.sol\";\n\ncontract BMath is BBronze, BConst, BNum {\n    /**********************************************************************************************\n    // calcSpotPrice                                                                             //\n    // sP = spotPrice                                                                            //\n    // bI = tokenBalanceIn                ( bI / wI )         1                                  //\n    // bO = tokenBalanceOut         sP =  -----------  *  ----------                             //\n    // wI = tokenWeightIn                 ( bO / wO )     ( 1 - sF )                             //\n    // wO = tokenWeightOut                                                                       //\n    // sF = swapFee                                                                              //\n    **********************************************************************************************/\n    function calcSpotPrice(\n        uint tokenBalanceIn,\n        uint tokenWeightIn,\n        uint tokenBalanceOut,\n        uint tokenWeightOut,\n        uint swapFee\n    )\n        public pure\n        returns (uint spotPrice)\n    {\n        uint numer = bdiv(tokenBalanceIn, tokenWeightIn);\n        uint denom = bdiv(tokenBalanceOut, tokenWeightOut);\n        uint ratio = bdiv(numer, denom);\n        uint scale = bdiv(BONE, bsub(BONE, swapFee));\n        return  (spotPrice = bmul(ratio, scale));\n    }\n\n    /**********************************************************************************************\n    // calcOutGivenIn                                                                            //\n    // aO = tokenAmountOut                                                                       //\n    // bO = tokenBalanceOut                                                                      //\n    // bI = tokenBalanceIn              /      /            bI             \\    (wI / wO) \\      //\n    // aI = tokenAmountIn    aO = bO * |  1 - | --------------------------  | ^            |     //\n    // wI = tokenWeightIn               \\      \\ ( bI + ( aI * ( 1 - sF )) /              /      //\n    // wO = tokenWeightOut                                                                       //\n    // sF = swapFee                                                                              //\n    **********************************************************************************************/\n    function calcOutGivenIn(\n        uint tokenBalanceIn,\n        uint tokenWeightIn,\n        uint tokenBalanceOut,\n        uint tokenWeightOut,\n        uint tokenAmountIn,\n        uint swapFee\n    )\n        public pure\n        returns (uint tokenAmountOut)\n    {\n        uint weightRatio = bdiv(tokenWeightIn, tokenWeightOut);\n        uint adjustedIn = bsub(BONE, swapFee);\n        adjustedIn = bmul(tokenAmountIn, adjustedIn);\n        uint y = bdiv(tokenBalanceIn, badd(tokenBalanceIn, adjustedIn));\n        uint foo = bpow(y, weightRatio);\n        uint bar = bsub(BONE, foo);\n        tokenAmountOut = bmul(tokenBalanceOut, bar);\n        return tokenAmountOut;\n    }\n\n    /**********************************************************************************************\n    // calcInGivenOut                                                                            //\n    // aI = tokenAmountIn                                                                        //\n    // bO = tokenBalanceOut               /  /     bO      \\    (wO / wI)      \\                 //\n    // bI = tokenBalanceIn          bI * |  | ------------  | ^            - 1  |                //\n    // aO = tokenAmountOut    aI =        \\  \\ ( bO - aO ) /                   /                 //\n    // wI = tokenWeightIn           --------------------------------------------                 //\n    // wO = tokenWeightOut                          ( 1 - sF )                                   //\n    // sF = swapFee                                                                              //\n    **********************************************************************************************/\n    function calcInGivenOut(\n        uint tokenBalanceIn,\n        uint tokenWeightIn,\n        uint tokenBalanceOut,\n        uint tokenWeightOut,\n        uint tokenAmountOut,\n        uint swapFee\n    )\n        public pure\n        returns (uint tokenAmountIn)\n    {\n        uint weightRatio = bdiv(tokenWeightOut, tokenWeightIn);\n        uint diff = bsub(tokenBalanceOut, tokenAmountOut);\n        uint y = bdiv(tokenBalanceOut, diff);\n        uint foo = bpow(y, weightRatio);\n        foo = bsub(foo, BONE);\n        tokenAmountIn = bsub(BONE, swapFee);\n        tokenAmountIn = bdiv(bmul(tokenBalanceIn, foo), tokenAmountIn);\n        return tokenAmountIn;\n    }\n\n    /**********************************************************************************************\n    // calcPoolOutGivenSingleIn                                                                  //\n    // pAo = poolAmountOut         /                                              \\              //\n    // tAi = tokenAmountIn        ///      /     //    wI \\      \\\\       \\     wI \\             //\n    // wI = tokenWeightIn        //| tAi *| 1 - || 1 - --  | * sF || + tBi \\    --  \\            //\n    // tW = totalWeight     pAo=||  \\      \\     \\\\    tW /      //         | ^ tW   | * pS - pS //\n    // tBi = tokenBalanceIn      \\\\  ------------------------------------- /        /            //\n    // pS = poolSupply            \\\\                    tBi               /        /             //\n    // sF = swapFee                \\                                              /              //\n    **********************************************************************************************/\n    function calcPoolOutGivenSingleIn(\n        uint tokenBalanceIn,\n        uint tokenWeightIn,\n        uint poolSupply,\n        uint totalWeight,\n        uint tokenAmountIn,\n        uint swapFee\n    )\n        public pure\n        returns (uint poolAmountOut)\n    {\n        // Charge the trading fee for the proportion of tokenAi\n        ///  which is implicitly traded to the other pool tokens.\n        // That proportion is (1- weightTokenIn)\n        // tokenAiAfterFee = tAi * (1 - (1-weightTi) * poolFee);\n        uint normalizedWeight = bdiv(tokenWeightIn, totalWeight);\n        uint zaz = bmul(bsub(BONE, normalizedWeight), swapFee); \n        uint tokenAmountInAfterFee = bmul(tokenAmountIn, bsub(BONE, zaz));\n\n        uint newTokenBalanceIn = badd(tokenBalanceIn, tokenAmountInAfterFee);\n        uint tokenInRatio = bdiv(newTokenBalanceIn, tokenBalanceIn);\n\n        // uint newPoolSupply = (ratioTi ^ weightTi) * poolSupply;\n        uint poolRatio = bpow(tokenInRatio, normalizedWeight);\n        uint newPoolSupply = bmul(poolRatio, poolSupply);\n        poolAmountOut = bsub(newPoolSupply, poolSupply);\n        return poolAmountOut;\n    }\n\n    /**********************************************************************************************\n    // calcSingleInGivenPoolOut                                                                  //\n    // tAi = tokenAmountIn              //(pS + pAo)\\     /    1    \\\\                           //\n    // pS = poolSupply                 || ---------  | ^ | --------- || * bI - bI                //\n    // pAo = poolAmountOut              \\\\    pS    /     \\(wI / tW)//                           //\n    // bI = balanceIn          tAi =  --------------------------------------------               //\n    // wI = weightIn                              /      wI  \\                                   //\n    // tW = totalWeight                          |  1 - ----  |  * sF                            //\n    // sF = swapFee                               \\      tW  /                                   //\n    **********************************************************************************************/\n    function calcSingleInGivenPoolOut(\n        uint tokenBalanceIn,\n        uint tokenWeightIn,\n        uint poolSupply,\n        uint totalWeight,\n        uint poolAmountOut,\n        uint swapFee\n    )\n        public pure\n        returns (uint tokenAmountIn)\n    {\n        uint normalizedWeight = bdiv(tokenWeightIn, totalWeight);\n        uint newPoolSupply = badd(poolSupply, poolAmountOut);\n        uint poolRatio = bdiv(newPoolSupply, poolSupply);\n      \n        //uint newBalTi = poolRatio^(1/weightTi) * balTi;\n        uint boo = bdiv(BONE, normalizedWeight); \n        uint tokenInRatio = bpow(poolRatio, boo);\n        uint newTokenBalanceIn = bmul(tokenInRatio, tokenBalanceIn);\n        uint tokenAmountInAfterFee = bsub(newTokenBalanceIn, tokenBalanceIn);\n        // Do reverse order of fees charged in joinswap_ExternAmountIn, this way \n        //     ``` pAo == joinswap_ExternAmountIn(Ti, joinswap_PoolAmountOut(pAo, Ti)) ```\n        //uint tAi = tAiAfterFee / (1 - (1-weightTi) * swapFee) ;\n        uint zar = bmul(bsub(BONE, normalizedWeight), swapFee);\n        tokenAmountIn = bdiv(tokenAmountInAfterFee, bsub(BONE, zar));\n        return tokenAmountIn;\n    }\n\n    /**********************************************************************************************\n    // calcSingleOutGivenPoolIn                                                                  //\n    // tAo = tokenAmountOut            /      /                                             \\\\   //\n    // bO = tokenBalanceOut           /      // pS - (pAi * (1 - eF)) \\     /    1    \\      \\\\  //\n    // pAi = poolAmountIn            | bO - || ----------------------- | ^ | --------- | * b0 || //\n    // ps = poolSupply                \\      \\\\          pS           /     \\(wO / tW)/      //  //\n    // wI = tokenWeightIn      tAo =   \\      \\                                             //   //\n    // tW = totalWeight                    /     /      wO \\       \\                             //\n    // sF = swapFee                    *  | 1 - |  1 - ---- | * sF  |                            //\n    // eF = exitFee                        \\     \\      tW /       /                             //\n    **********************************************************************************************/\n    function calcSingleOutGivenPoolIn(\n        uint tokenBalanceOut,\n        uint tokenWeightOut,\n        uint poolSupply,\n        uint totalWeight,\n        uint poolAmountIn,\n        uint swapFee\n    )\n        public pure\n        returns (uint tokenAmountOut)\n    {\n        uint normalizedWeight = bdiv(tokenWeightOut, totalWeight);\n        // charge exit fee on the pool token side\n        // pAiAfterExitFee = pAi*(1-exitFee)\n        uint poolAmountInAfterExitFee = bmul(poolAmountIn, bsub(BONE, EXIT_FEE));\n        uint newPoolSupply = bsub(poolSupply, poolAmountInAfterExitFee);\n        uint poolRatio = bdiv(newPoolSupply, poolSupply);\n     \n        // newBalTo = poolRatio^(1/weightTo) * balTo;\n        uint tokenOutRatio = bpow(poolRatio, bdiv(BONE, normalizedWeight));\n        uint newTokenBalanceOut = bmul(tokenOutRatio, tokenBalanceOut);\n\n        uint tokenAmountOutBeforeSwapFee = bsub(tokenBalanceOut, newTokenBalanceOut);\n\n        // charge swap fee on the output token side \n        //uint tAo = tAoBeforeSwapFee * (1 - (1-weightTo) * swapFee)\n        uint zaz = bmul(bsub(BONE, normalizedWeight), swapFee); \n        tokenAmountOut = bmul(tokenAmountOutBeforeSwapFee, bsub(BONE, zaz));\n        return tokenAmountOut;\n    }\n\n    /**********************************************************************************************\n    // calcPoolInGivenSingleOut                                                                  //\n    // pAi = poolAmountIn               // /               tAo             \\\\     / wO \\     \\   //\n    // bO = tokenBalanceOut            // | bO - -------------------------- |\\   | ---- |     \\  //\n    // tAo = tokenAmountOut      pS - ||   \\     1 - ((1 - (tO / tW)) * sF)/  | ^ \\ tW /  * pS | //\n    // ps = poolSupply                 \\\\ -----------------------------------/                /  //\n    // wO = tokenWeightOut  pAi =       \\\\               bO                 /                /   //\n    // tW = totalWeight           -------------------------------------------------------------  //\n    // sF = swapFee                                        ( 1 - eF )                            //\n    // eF = exitFee                                                                              //\n    **********************************************************************************************/\n    function calcPoolInGivenSingleOut(\n        uint tokenBalanceOut,\n        uint tokenWeightOut,\n        uint poolSupply,\n        uint totalWeight,\n        uint tokenAmountOut,\n        uint swapFee\n    )\n        public pure\n        returns (uint poolAmountIn)\n    {\n\n        // charge swap fee on the output token side \n        uint normalizedWeight = bdiv(tokenWeightOut, totalWeight);\n        //uint tAoBeforeSwapFee = tAo / (1 - (1-weightTo) * swapFee) ;\n        uint zoo = bsub(BONE, normalizedWeight);\n        uint zar = bmul(zoo, swapFee); \n        uint tokenAmountOutBeforeSwapFee = bdiv(tokenAmountOut, bsub(BONE, zar));\n\n        uint newTokenBalanceOut = bsub(tokenBalanceOut, tokenAmountOutBeforeSwapFee);\n        uint tokenOutRatio = bdiv(newTokenBalanceOut, tokenBalanceOut);\n\n        //uint newPoolSupply = (ratioTo ^ weightTo) * poolSupply;\n        uint poolRatio = bpow(tokenOutRatio, normalizedWeight);\n        uint newPoolSupply = bmul(poolRatio, poolSupply);\n        uint poolAmountInAfterExitFee = bsub(poolSupply, newPoolSupply);\n\n        // charge exit fee on the pool token side\n        // pAi = pAiAfterExitFee/(1-exitFee)\n        poolAmountIn = bdiv(poolAmountInAfterExitFee, bsub(BONE, EXIT_FEE));\n        return poolAmountIn;\n    }\n\n\n}\n"},"BNum.sol":{"content":"// This program is free software: you can redistribute it and/or modify\n// it under the terms of the GNU General Public License as published by\n// the Free Software Foundation, either version 3 of the License, or\n// (at your option) any later version.\n\n// This program is distributed in the hope that it will be useful,\n// but WITHOUT ANY WARRANTY; without even the implied warranty of\n// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the\n// GNU General Public License for more details.\n\n// You should have received a copy of the GNU General Public License\n// along with this program.  If not, see \u003chttp://www.gnu.org/licenses/\u003e.\n\npragma solidity 0.5.12;\n\nimport \"./BConst.sol\";\n\ncontract BNum is BConst {\n\n    function btoi(uint a)\n        internal pure \n        returns (uint)\n    {\n        return a / BONE;\n    }\n\n    function bfloor(uint a)\n        internal pure\n        returns (uint)\n    {\n        return btoi(a) * BONE;\n    }\n\n    function badd(uint a, uint b)\n        internal pure\n        returns (uint)\n    {\n        uint c = a + b;\n        require(c \u003e= a, \"ERR_ADD_OVERFLOW\");\n        return c;\n    }\n\n    function bsub(uint a, uint b)\n        internal pure\n        returns (uint)\n    {\n        (uint c, bool flag) = bsubSign(a, b);\n        require(!flag, \"ERR_SUB_UNDERFLOW\");\n        return c;\n    }\n\n    function bsubSign(uint a, uint b)\n        internal pure\n        returns (uint, bool)\n    {\n        if (a \u003e= b) {\n            return (a - b, false);\n        } else {\n            return (b - a, true);\n        }\n    }\n\n    function bmul(uint a, uint b)\n        internal pure\n        returns (uint)\n    {\n        uint c0 = a * b;\n        require(a == 0 || c0 / a == b, \"ERR_MUL_OVERFLOW\");\n        uint c1 = c0 + (BONE / 2);\n        require(c1 \u003e= c0, \"ERR_MUL_OVERFLOW\");\n        uint c2 = c1 / BONE;\n        return c2;\n    }\n\n    function bdiv(uint a, uint b)\n        internal pure\n        returns (uint)\n    {\n        require(b != 0, \"ERR_DIV_ZERO\");\n        uint c0 = a * BONE;\n        require(a == 0 || c0 / a == BONE, \"ERR_DIV_INTERNAL\"); // bmul overflow\n        uint c1 = c0 + (b / 2);\n        require(c1 \u003e= c0, \"ERR_DIV_INTERNAL\"); //  badd require\n        uint c2 = c1 / b;\n        return c2;\n    }\n\n    // DSMath.wpow\n    function bpowi(uint a, uint n)\n        internal pure\n        returns (uint)\n    {\n        uint z = n % 2 != 0 ? a : BONE;\n\n        for (n /= 2; n != 0; n /= 2) {\n            a = bmul(a, a);\n\n            if (n % 2 != 0) {\n                z = bmul(z, a);\n            }\n        }\n        return z;\n    }\n\n    // Compute b^(e.w) by splitting it into (b^e)*(b^0.w).\n    // Use `bpowi` for `b^e` and `bpowK` for k iterations\n    // of approximation of b^0.w\n    function bpow(uint base, uint exp)\n        internal pure\n        returns (uint)\n    {\n        require(base \u003e= MIN_BPOW_BASE, \"ERR_BPOW_BASE_TOO_LOW\");\n        require(base \u003c= MAX_BPOW_BASE, \"ERR_BPOW_BASE_TOO_HIGH\");\n\n        uint whole  = bfloor(exp);   \n        uint remain = bsub(exp, whole);\n\n        uint wholePow = bpowi(base, btoi(whole));\n\n        if (remain == 0) {\n            return wholePow;\n        }\n\n        uint partialResult = bpowApprox(base, remain, BPOW_PRECISION);\n        return bmul(wholePow, partialResult);\n    }\n\n    function bpowApprox(uint base, uint exp, uint precision)\n        internal pure\n        returns (uint)\n    {\n        // term 0:\n        uint a     = exp;\n        (uint x, bool xneg)  = bsubSign(base, BONE);\n        uint term = BONE;\n        uint sum   = term;\n        bool negative = false;\n\n\n        // term(k) = numer / denom \n        //         = (product(a - i - 1, i=1--\u003ek) * x^k) / (k!)\n        // each iteration, multiply previous term by (a-(k-1)) * x / k\n        // continue until term is less than precision\n        for (uint i = 1; term \u003e= precision; i++) {\n            uint bigK = i * BONE;\n            (uint c, bool cneg) = bsubSign(a, bsub(bigK, BONE));\n            term = bmul(term, bmul(c, x));\n            term = bdiv(term, bigK);\n            if (term == 0) break;\n\n            if (xneg) negative = !negative;\n            if (cneg) negative = !negative;\n            if (negative) {\n                sum = bsub(sum, term);\n            } else {\n                sum = badd(sum, term);\n            }\n        }\n\n        return sum;\n    }\n\n}\n"},"BPool.sol":{"content":"// This program is free software: you can redistribute it and/or modify\n// it under the terms of the GNU General Public License as published by\n// the Free Software Foundation, either version 3 of the License, or\n// (at your option) any later version.\n\n// This program is distributed in the hope that it will be useful,\n// but WITHOUT ANY WARRANTY; without even the implied warranty of\n// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the\n// GNU General Public License for more details.\n\n// You should have received a copy of the GNU General Public License\n// along with this program.  If not, see \u003chttp://www.gnu.org/licenses/\u003e.\n\npragma solidity 0.5.12;\n\nimport \"./BToken.sol\";\nimport \"./BMath.sol\";\n\ncontract BPool is BBronze, BToken, BMath {\n\n    struct Record {\n        bool bound;   // is token bound to pool\n        uint index;   // private\n        uint denorm;  // denormalized weight\n        uint balance;\n    }\n\n    event LOG_SWAP(\n        address indexed caller,\n        address indexed tokenIn,\n        address indexed tokenOut,\n        uint256         tokenAmountIn,\n        uint256         tokenAmountOut\n    );\n\n    event LOG_JOIN(\n        address indexed caller,\n        address indexed tokenIn,\n        uint256         tokenAmountIn\n    );\n\n    event LOG_EXIT(\n        address indexed caller,\n        address indexed tokenOut,\n        uint256         tokenAmountOut\n    );\n\n    event LOG_CALL(\n        bytes4  indexed sig,\n        address indexed caller,\n        bytes           data\n    ) anonymous;\n\n    modifier _logs_() {\n        emit LOG_CALL(msg.sig, msg.sender, msg.data);\n        _;\n    }\n\n    modifier _lock_() {\n        require(!_mutex, \"ERR_REENTRY\");\n        _mutex = true;\n        _;\n        _mutex = false;\n    }\n\n    modifier _viewlock_() {\n        require(!_mutex, \"ERR_REENTRY\");\n        _;\n    }\n\n    bool private _mutex;\n\n    address private _factory;    // BFactory address to push token exitFee to\n    address private _controller; // has CONTROL role\n    bool private _publicSwap; // true if PUBLIC can call SWAP functions\n\n    // `setSwapFee` and `finalize` require CONTROL\n    // `finalize` sets `PUBLIC can SWAP`, `PUBLIC can JOIN`\n    uint private _swapFee;\n    bool private _finalized;\n\n    address[] private _tokens;\n    mapping(address=\u003eRecord) private  _records;\n    uint private _totalWeight;\n\n    constructor() public {\n        _controller = msg.sender;\n        _factory = msg.sender;\n        _swapFee = MIN_FEE;\n        _publicSwap = false;\n        _finalized = false;\n    }\n\n    function isPublicSwap()\n        external view\n        returns (bool)\n    {\n        return _publicSwap;\n    }\n\n    function isFinalized()\n        external view\n        returns (bool)\n    {\n        return _finalized;\n    }\n\n    function isBound(address t)\n        external view\n        returns (bool)\n    {\n        return _records[t].bound;\n    }\n\n    function getNumTokens()\n        external view\n        returns (uint) \n    {\n        return _tokens.length;\n    }\n\n    function getCurrentTokens()\n        external view _viewlock_\n        returns (address[] memory tokens)\n    {\n        return _tokens;\n    }\n\n    function getFinalTokens()\n        external view\n        _viewlock_\n        returns (address[] memory tokens)\n    {\n        require(_finalized, \"ERR_NOT_FINALIZED\");\n        return _tokens;\n    }\n\n    function getDenormalizedWeight(address token)\n        external view\n        _viewlock_\n        returns (uint)\n    {\n\n        require(_records[token].bound, \"ERR_NOT_BOUND\");\n        return _records[token].denorm;\n    }\n\n    function getTotalDenormalizedWeight()\n        external view\n        _viewlock_\n        returns (uint)\n    {\n        return _totalWeight;\n    }\n\n    function getNormalizedWeight(address token)\n        external view\n        _viewlock_\n        returns (uint)\n    {\n\n        require(_records[token].bound, \"ERR_NOT_BOUND\");\n        uint denorm = _records[token].denorm;\n        return bdiv(denorm, _totalWeight);\n    }\n\n    function getBalance(address token)\n        external view\n        _viewlock_\n        returns (uint)\n    {\n\n        require(_records[token].bound, \"ERR_NOT_BOUND\");\n        return _records[token].balance;\n    }\n\n    function getSwapFee()\n        external view\n        _viewlock_\n        returns (uint)\n    {\n        return _swapFee;\n    }\n\n    function getController()\n        external view\n        _viewlock_\n        returns (address)\n    {\n        return _controller;\n    }\n\n    function setSwapFee(uint swapFee)\n        external\n        _logs_\n        _lock_\n    { \n        require(!_finalized, \"ERR_IS_FINALIZED\");\n        require(msg.sender == _controller, \"ERR_NOT_CONTROLLER\");\n        require(swapFee \u003e= MIN_FEE, \"ERR_MIN_FEE\");\n        require(swapFee \u003c= MAX_FEE, \"ERR_MAX_FEE\");\n        _swapFee = swapFee;\n    }\n\n    function setController(address manager)\n        external\n        _logs_\n        _lock_\n    {\n        require(msg.sender == _controller, \"ERR_NOT_CONTROLLER\");\n        _controller = manager;\n    }\n\n    function setPublicSwap(bool public_)\n        external\n        _logs_\n        _lock_\n    {\n        require(!_finalized, \"ERR_IS_FINALIZED\");\n        require(msg.sender == _controller, \"ERR_NOT_CONTROLLER\");\n        _publicSwap = public_;\n    }\n\n    function finalize()\n        external\n        _logs_\n        _lock_\n    {\n        require(msg.sender == _controller, \"ERR_NOT_CONTROLLER\");\n        require(!_finalized, \"ERR_IS_FINALIZED\");\n        require(_tokens.length \u003e= MIN_BOUND_TOKENS, \"ERR_MIN_TOKENS\");\n\n        _finalized = true;\n        _publicSwap = true;\n\n        _mintPoolShare(INIT_POOL_SUPPLY);\n        _pushPoolShare(msg.sender, INIT_POOL_SUPPLY);\n    }\n\n\n    function bind(address token, uint balance, uint denorm)\n        external\n        _logs_\n        // _lock_  Bind does not lock because it jumps to `rebind`, which does\n    {\n        require(msg.sender == _controller, \"ERR_NOT_CONTROLLER\");\n        require(!_records[token].bound, \"ERR_IS_BOUND\");\n        require(!_finalized, \"ERR_IS_FINALIZED\");\n\n        require(_tokens.length \u003c MAX_BOUND_TOKENS, \"ERR_MAX_TOKENS\");\n\n        _records[token] = Record({\n            bound: true,\n            index: _tokens.length,\n            denorm: 0,    // balance and denorm will be validated\n            balance: 0   // and set by `rebind`\n        });\n        _tokens.push(token);\n        rebind(token, balance, denorm);\n    }\n\n    function rebind(address token, uint balance, uint denorm)\n        public\n        _logs_\n        _lock_\n    {\n\n        require(msg.sender == _controller, \"ERR_NOT_CONTROLLER\");\n        require(_records[token].bound, \"ERR_NOT_BOUND\");\n        require(!_finalized, \"ERR_IS_FINALIZED\");\n\n        require(denorm \u003e= MIN_WEIGHT, \"ERR_MIN_WEIGHT\");\n        require(denorm \u003c= MAX_WEIGHT, \"ERR_MAX_WEIGHT\");\n        require(balance \u003e= MIN_BALANCE, \"ERR_MIN_BALANCE\");\n\n        // Adjust the denorm and totalWeight\n        uint oldWeight = _records[token].denorm;\n        if (denorm \u003e oldWeight) {\n            _totalWeight = badd(_totalWeight, bsub(denorm, oldWeight));\n            require(_totalWeight \u003c= MAX_TOTAL_WEIGHT, \"ERR_MAX_TOTAL_WEIGHT\");\n        } else if (denorm \u003c oldWeight) {\n            _totalWeight = bsub(_totalWeight, bsub(oldWeight, denorm));\n        }        \n        _records[token].denorm = denorm;\n\n        // Adjust the balance record and actual token balance\n        uint oldBalance = _records[token].balance;\n        _records[token].balance = balance;\n        if (balance \u003e oldBalance) {\n            _pullUnderlying(token, msg.sender, bsub(balance, oldBalance));\n        } else if (balance \u003c oldBalance) {\n            // In this case liquidity is being withdrawn, so charge EXIT_FEE\n            uint tokenBalanceWithdrawn = bsub(oldBalance, balance);\n            uint tokenExitFee = bmul(tokenBalanceWithdrawn, EXIT_FEE);\n            _pushUnderlying(token, msg.sender, bsub(tokenBalanceWithdrawn, tokenExitFee));\n            _pushUnderlying(token, _factory, tokenExitFee);\n        }\n    }\n\n    function unbind(address token)\n        external\n        _logs_\n        _lock_\n    {\n\n        require(msg.sender == _controller, \"ERR_NOT_CONTROLLER\");\n        require(_records[token].bound, \"ERR_NOT_BOUND\");\n        require(!_finalized, \"ERR_IS_FINALIZED\");\n\n        uint tokenBalance = _records[token].balance;\n        uint tokenExitFee = bmul(tokenBalance, EXIT_FEE);\n\n        _totalWeight = bsub(_totalWeight, _records[token].denorm);\n\n        // Swap the token-to-unbind with the last token,\n        // then delete the last token\n        uint index = _records[token].index;\n        uint last = _tokens.length - 1;\n        _tokens[index] = _tokens[last];\n        _records[_tokens[index]].index = index;\n        _tokens.pop();\n        _records[token] = Record({\n            bound: false,\n            index: 0,\n            denorm: 0,\n            balance: 0\n        });\n\n        _pushUnderlying(token, msg.sender, bsub(tokenBalance, tokenExitFee));\n        _pushUnderlying(token, _factory, tokenExitFee);\n    }\n\n    // Absorb any tokens that have been sent to this contract into the pool\n    function gulp(address token)\n        external\n        _logs_\n        _lock_\n    {\n        require(_records[token].bound, \"ERR_NOT_BOUND\");\n        _records[token].balance = IERC20(token).balanceOf(address(this));\n    }\n\n    function getSpotPrice(address tokenIn, address tokenOut)\n        external view\n        _viewlock_\n        returns (uint spotPrice)\n    {\n        require(_records[tokenIn].bound, \"ERR_NOT_BOUND\");\n        require(_records[tokenOut].bound, \"ERR_NOT_BOUND\");\n        Record storage inRecord = _records[tokenIn];\n        Record storage outRecord = _records[tokenOut];\n        return calcSpotPrice(inRecord.balance, inRecord.denorm, outRecord.balance, outRecord.denorm, _swapFee);\n    }\n\n    function getSpotPriceSansFee(address tokenIn, address tokenOut)\n        external view\n        _viewlock_\n        returns (uint spotPrice)\n    {\n        require(_records[tokenIn].bound, \"ERR_NOT_BOUND\");\n        require(_records[tokenOut].bound, \"ERR_NOT_BOUND\");\n        Record storage inRecord = _records[tokenIn];\n        Record storage outRecord = _records[tokenOut];\n        return calcSpotPrice(inRecord.balance, inRecord.denorm, outRecord.balance, outRecord.denorm, 0);\n    }\n\n    function joinPool(uint poolAmountOut, uint[] calldata maxAmountsIn)\n        external\n        _logs_\n        _lock_\n    {\n        require(_finalized, \"ERR_NOT_FINALIZED\");\n\n        uint poolTotal = totalSupply();\n        uint ratio = bdiv(poolAmountOut, poolTotal);\n        require(ratio != 0, \"ERR_MATH_APPROX\");\n\n        for (uint i = 0; i \u003c _tokens.length; i++) {\n            address t = _tokens[i];\n            uint bal = _records[t].balance;\n            uint tokenAmountIn = bmul(ratio, bal);\n            require(tokenAmountIn != 0, \"ERR_MATH_APPROX\");\n            require(tokenAmountIn \u003c= maxAmountsIn[i], \"ERR_LIMIT_IN\");\n            _records[t].balance = badd(_records[t].balance, tokenAmountIn);\n            emit LOG_JOIN(msg.sender, t, tokenAmountIn);\n            _pullUnderlying(t, msg.sender, tokenAmountIn);\n        }\n        _mintPoolShare(poolAmountOut);\n        _pushPoolShare(msg.sender, poolAmountOut);\n    }\n\n    function exitPool(uint poolAmountIn, uint[] calldata minAmountsOut)\n        external\n        _logs_\n        _lock_\n    {\n        require(_finalized, \"ERR_NOT_FINALIZED\");\n\n        uint poolTotal = totalSupply();\n        uint exitFee = bmul(poolAmountIn, EXIT_FEE);\n        uint pAiAfterExitFee = bsub(poolAmountIn, exitFee);\n        uint ratio = bdiv(pAiAfterExitFee, poolTotal);\n        require(ratio != 0, \"ERR_MATH_APPROX\");\n\n        _pullPoolShare(msg.sender, poolAmountIn);\n        _pushPoolShare(_factory, exitFee);\n        _burnPoolShare(pAiAfterExitFee);\n\n        for (uint i = 0; i \u003c _tokens.length; i++) {\n            address t = _tokens[i];\n            uint bal = _records[t].balance;\n            uint tokenAmountOut = bmul(ratio, bal);\n            require(tokenAmountOut != 0, \"ERR_MATH_APPROX\");\n            require(tokenAmountOut \u003e= minAmountsOut[i], \"ERR_LIMIT_OUT\");\n            _records[t].balance = bsub(_records[t].balance, tokenAmountOut);\n            emit LOG_EXIT(msg.sender, t, tokenAmountOut);\n            _pushUnderlying(t, msg.sender, tokenAmountOut);\n        }\n\n    }\n\n\n    function swapExactAmountIn(\n        address tokenIn,\n        uint tokenAmountIn,\n        address tokenOut,\n        uint minAmountOut,\n        uint maxPrice\n    )\n        external\n        _logs_\n        _lock_\n        returns (uint tokenAmountOut, uint spotPriceAfter)\n    {\n\n        require(_records[tokenIn].bound, \"ERR_NOT_BOUND\");\n        require(_records[tokenOut].bound, \"ERR_NOT_BOUND\");\n        require(_publicSwap, \"ERR_SWAP_NOT_PUBLIC\");\n\n        Record storage inRecord = _records[address(tokenIn)];\n        Record storage outRecord = _records[address(tokenOut)];\n\n        require(tokenAmountIn \u003c= bmul(inRecord.balance, MAX_IN_RATIO), \"ERR_MAX_IN_RATIO\");\n\n        uint spotPriceBefore = calcSpotPrice(\n                                    inRecord.balance,\n                                    inRecord.denorm,\n                                    outRecord.balance,\n                                    outRecord.denorm,\n                                    _swapFee\n                                );\n        require(spotPriceBefore \u003c= maxPrice, \"ERR_BAD_LIMIT_PRICE\");\n\n        tokenAmountOut = calcOutGivenIn(\n                            inRecord.balance,\n                            inRecord.denorm,\n                            outRecord.balance,\n                            outRecord.denorm,\n                            tokenAmountIn,\n                            _swapFee\n                        );\n        require(tokenAmountOut \u003e= minAmountOut, \"ERR_LIMIT_OUT\");\n\n        inRecord.balance = badd(inRecord.balance, tokenAmountIn);\n        outRecord.balance = bsub(outRecord.balance, tokenAmountOut);\n\n        spotPriceAfter = calcSpotPrice(\n                                inRecord.balance,\n                                inRecord.denorm,\n                                outRecord.balance,\n                                outRecord.denorm,\n                                _swapFee\n                            );\n        require(spotPriceAfter \u003e= spotPriceBefore, \"ERR_MATH_APPROX\");     \n        require(spotPriceAfter \u003c= maxPrice, \"ERR_LIMIT_PRICE\");\n        require(spotPriceBefore \u003c= bdiv(tokenAmountIn, tokenAmountOut), \"ERR_MATH_APPROX\");\n\n        emit LOG_SWAP(msg.sender, tokenIn, tokenOut, tokenAmountIn, tokenAmountOut);\n\n        _pullUnderlying(tokenIn, msg.sender, tokenAmountIn);\n        _pushUnderlying(tokenOut, msg.sender, tokenAmountOut);\n\n        return (tokenAmountOut, spotPriceAfter);\n    }\n\n    function swapExactAmountOut(\n        address tokenIn,\n        uint maxAmountIn,\n        address tokenOut,\n        uint tokenAmountOut,\n        uint maxPrice\n    )\n        external\n        _logs_\n        _lock_ \n        returns (uint tokenAmountIn, uint spotPriceAfter)\n    {\n        require(_records[tokenIn].bound, \"ERR_NOT_BOUND\");\n        require(_records[tokenOut].bound, \"ERR_NOT_BOUND\");\n        require(_publicSwap, \"ERR_SWAP_NOT_PUBLIC\");\n\n        Record storage inRecord = _records[address(tokenIn)];\n        Record storage outRecord = _records[address(tokenOut)];\n\n        require(tokenAmountOut \u003c= bmul(outRecord.balance, MAX_OUT_RATIO), \"ERR_MAX_OUT_RATIO\");\n\n        uint spotPriceBefore = calcSpotPrice(\n                                    inRecord.balance,\n                                    inRecord.denorm,\n                                    outRecord.balance,\n                                    outRecord.denorm,\n                                    _swapFee\n                                );\n        require(spotPriceBefore \u003c= maxPrice, \"ERR_BAD_LIMIT_PRICE\");\n\n        tokenAmountIn = calcInGivenOut(\n                            inRecord.balance,\n                            inRecord.denorm,\n                            outRecord.balance,\n                            outRecord.denorm,\n                            tokenAmountOut,\n                            _swapFee\n                        );\n        require(tokenAmountIn \u003c= maxAmountIn, \"ERR_LIMIT_IN\");\n\n        inRecord.balance = badd(inRecord.balance, tokenAmountIn);\n        outRecord.balance = bsub(outRecord.balance, tokenAmountOut);\n\n        spotPriceAfter = calcSpotPrice(\n                                inRecord.balance,\n                                inRecord.denorm,\n                                outRecord.balance,\n                                outRecord.denorm,\n                                _swapFee\n                            );\n        require(spotPriceAfter \u003e= spotPriceBefore, \"ERR_MATH_APPROX\");\n        require(spotPriceAfter \u003c= maxPrice, \"ERR_LIMIT_PRICE\");\n        require(spotPriceBefore \u003c= bdiv(tokenAmountIn, tokenAmountOut), \"ERR_MATH_APPROX\");\n\n        emit LOG_SWAP(msg.sender, tokenIn, tokenOut, tokenAmountIn, tokenAmountOut);\n\n        _pullUnderlying(tokenIn, msg.sender, tokenAmountIn);\n        _pushUnderlying(tokenOut, msg.sender, tokenAmountOut);\n\n        return (tokenAmountIn, spotPriceAfter);\n    }\n\n\n    function joinswapExternAmountIn(address tokenIn, uint tokenAmountIn, uint minPoolAmountOut)\n        external\n        _logs_\n        _lock_\n        returns (uint poolAmountOut)\n\n    {        \n        require(_finalized, \"ERR_NOT_FINALIZED\");\n        require(_records[tokenIn].bound, \"ERR_NOT_BOUND\");\n        require(tokenAmountIn \u003c= bmul(_records[tokenIn].balance, MAX_IN_RATIO), \"ERR_MAX_IN_RATIO\");\n\n        Record storage inRecord = _records[tokenIn];\n\n        poolAmountOut = calcPoolOutGivenSingleIn(\n                            inRecord.balance,\n                            inRecord.denorm,\n                            _totalSupply,\n                            _totalWeight,\n                            tokenAmountIn,\n                            _swapFee\n                        );\n\n        require(poolAmountOut \u003e= minPoolAmountOut, \"ERR_LIMIT_OUT\");\n\n        inRecord.balance = badd(inRecord.balance, tokenAmountIn);\n\n        emit LOG_JOIN(msg.sender, tokenIn, tokenAmountIn);\n\n        _mintPoolShare(poolAmountOut);\n        _pushPoolShare(msg.sender, poolAmountOut);\n        _pullUnderlying(tokenIn, msg.sender, tokenAmountIn);\n\n        return poolAmountOut;\n    }\n\n    function joinswapPoolAmountOut(address tokenIn, uint poolAmountOut, uint maxAmountIn)\n        external\n        _logs_\n        _lock_\n        returns (uint tokenAmountIn)\n    {\n        require(_finalized, \"ERR_NOT_FINALIZED\");\n        require(_records[tokenIn].bound, \"ERR_NOT_BOUND\");\n\n        Record storage inRecord = _records[tokenIn];\n\n        tokenAmountIn = calcSingleInGivenPoolOut(\n                            inRecord.balance,\n                            inRecord.denorm,\n                            _totalSupply,\n                            _totalWeight,\n                            poolAmountOut,\n                            _swapFee\n                        );\n\n        require(tokenAmountIn != 0, \"ERR_MATH_APPROX\");\n        require(tokenAmountIn \u003c= maxAmountIn, \"ERR_LIMIT_IN\");\n        \n        require(tokenAmountIn \u003c= bmul(_records[tokenIn].balance, MAX_IN_RATIO), \"ERR_MAX_IN_RATIO\");\n\n        inRecord.balance = badd(inRecord.balance, tokenAmountIn);\n\n        emit LOG_JOIN(msg.sender, tokenIn, tokenAmountIn);\n\n        _mintPoolShare(poolAmountOut);\n        _pushPoolShare(msg.sender, poolAmountOut);\n        _pullUnderlying(tokenIn, msg.sender, tokenAmountIn);\n\n        return tokenAmountIn;\n    }\n\n    function exitswapPoolAmountIn(address tokenOut, uint poolAmountIn, uint minAmountOut)\n        external\n        _logs_\n        _lock_\n        returns (uint tokenAmountOut)\n    {\n        require(_finalized, \"ERR_NOT_FINALIZED\");\n        require(_records[tokenOut].bound, \"ERR_NOT_BOUND\");\n\n        Record storage outRecord = _records[tokenOut];\n\n        tokenAmountOut = calcSingleOutGivenPoolIn(\n                            outRecord.balance,\n                            outRecord.denorm,\n                            _totalSupply,\n                            _totalWeight,\n                            poolAmountIn,\n                            _swapFee\n                        );\n\n        require(tokenAmountOut \u003e= minAmountOut, \"ERR_LIMIT_OUT\");\n        \n        require(tokenAmountOut \u003c= bmul(_records[tokenOut].balance, MAX_OUT_RATIO), \"ERR_MAX_OUT_RATIO\");\n\n        outRecord.balance = bsub(outRecord.balance, tokenAmountOut);\n\n        uint exitFee = bmul(poolAmountIn, EXIT_FEE);\n\n        emit LOG_EXIT(msg.sender, tokenOut, tokenAmountOut);\n\n        _pullPoolShare(msg.sender, poolAmountIn);\n        _burnPoolShare(bsub(poolAmountIn, exitFee));\n        _pushPoolShare(_factory, exitFee);\n        _pushUnderlying(tokenOut, msg.sender, tokenAmountOut);\n\n        return tokenAmountOut;\n    }\n\n    function exitswapExternAmountOut(address tokenOut, uint tokenAmountOut, uint maxPoolAmountIn)\n        external\n        _logs_\n        _lock_\n        returns (uint poolAmountIn)\n    {\n        require(_finalized, \"ERR_NOT_FINALIZED\");\n        require(_records[tokenOut].bound, \"ERR_NOT_BOUND\");\n        require(tokenAmountOut \u003c= bmul(_records[tokenOut].balance, MAX_OUT_RATIO), \"ERR_MAX_OUT_RATIO\");\n\n        Record storage outRecord = _records[tokenOut];\n\n        poolAmountIn = calcPoolInGivenSingleOut(\n                            outRecord.balance,\n                            outRecord.denorm,\n                            _totalSupply,\n                            _totalWeight,\n                            tokenAmountOut,\n                            _swapFee\n                        );\n\n        require(poolAmountIn != 0, \"ERR_MATH_APPROX\");\n        require(poolAmountIn \u003c= maxPoolAmountIn, \"ERR_LIMIT_IN\");\n\n        outRecord.balance = bsub(outRecord.balance, tokenAmountOut);\n\n        uint exitFee = bmul(poolAmountIn, EXIT_FEE);\n\n        emit LOG_EXIT(msg.sender, tokenOut, tokenAmountOut);\n\n        _pullPoolShare(msg.sender, poolAmountIn);\n        _burnPoolShare(bsub(poolAmountIn, exitFee));\n        _pushPoolShare(_factory, exitFee);\n        _pushUnderlying(tokenOut, msg.sender, tokenAmountOut);        \n\n        return poolAmountIn;\n    }\n\n\n    // ==\n    // \u0027Underlying\u0027 token-manipulation functions make external calls but are NOT locked\n    // You must `_lock_` or otherwise ensure reentry-safety\n\n    function _pullUnderlying(address erc20, address from, uint amount)\n        internal\n    {\n        bool xfer = IERC20(erc20).transferFrom(from, address(this), amount);\n        require(xfer, \"ERR_ERC20_FALSE\");\n    }\n\n    function _pushUnderlying(address erc20, address to, uint amount)\n        internal\n    {\n        bool xfer = IERC20(erc20).transfer(to, amount);\n        require(xfer, \"ERR_ERC20_FALSE\");\n    }\n\n    function _pullPoolShare(address from, uint amount)\n        internal\n    {\n        _pull(from, amount);\n    }\n\n    function _pushPoolShare(address to, uint amount)\n        internal\n    {\n        _push(to, amount);\n    }\n\n    function _mintPoolShare(uint amount)\n        internal\n    {\n        _mint(amount);\n    }\n\n    function _burnPoolShare(uint amount)\n        internal\n    {\n        _burn(amount);\n    }\n\n}\n"},"BToken.sol":{"content":"// This program is free software: you can redistribute it and/or modify\n// it under the terms of the GNU General Public License as published by\n// the Free Software Foundation, either version 3 of the License, or\n// (at your option) any later version.\n\n// This program is distributed in the hope that it will be useful,\n// but WITHOUT ANY WARRANTY; without even the implied warranty of\n// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the\n// GNU General Public License for more details.\n\n// You should have received a copy of the GNU General Public License\n// along with this program.  If not, see \u003chttp://www.gnu.org/licenses/\u003e.\n\npragma solidity 0.5.12;\n\nimport \"./BNum.sol\";\n\n// Highly opinionated token implementation\n\ninterface IERC20 {\n    event Approval(address indexed src, address indexed dst, uint amt);\n    event Transfer(address indexed src, address indexed dst, uint amt);\n\n    function totalSupply() external view returns (uint);\n    function balanceOf(address whom) external view returns (uint);\n    function allowance(address src, address dst) external view returns (uint);\n\n    function approve(address dst, uint amt) external returns (bool);\n    function transfer(address dst, uint amt) external returns (bool);\n    function transferFrom(\n        address src, address dst, uint amt\n    ) external returns (bool);\n}\n\ncontract BTokenBase is BNum {\n\n    mapping(address =\u003e uint)                   internal _balance;\n    mapping(address =\u003e mapping(address=\u003euint)) internal _allowance;\n    uint internal _totalSupply;\n\n    event Approval(address indexed src, address indexed dst, uint amt);\n    event Transfer(address indexed src, address indexed dst, uint amt);\n\n    function _mint(uint amt) internal {\n        _balance[address(this)] = badd(_balance[address(this)], amt);\n        _totalSupply = badd(_totalSupply, amt);\n        emit Transfer(address(0), address(this), amt);\n    }\n\n    function _burn(uint amt) internal {\n        require(_balance[address(this)] \u003e= amt, \"ERR_INSUFFICIENT_BAL\");\n        _balance[address(this)] = bsub(_balance[address(this)], amt);\n        _totalSupply = bsub(_totalSupply, amt);\n        emit Transfer(address(this), address(0), amt);\n    }\n\n    function _move(address src, address dst, uint amt) internal {\n        require(_balance[src] \u003e= amt, \"ERR_INSUFFICIENT_BAL\");\n        _balance[src] = bsub(_balance[src], amt);\n        _balance[dst] = badd(_balance[dst], amt);\n        emit Transfer(src, dst, amt);\n    }\n\n    function _push(address to, uint amt) internal {\n        _move(address(this), to, amt);\n    }\n\n    function _pull(address from, uint amt) internal {\n        _move(from, address(this), amt);\n    }\n}\n\ncontract BToken is BTokenBase, IERC20 {\n\n    string  private _name     = \"Balancer Pool Token\";\n    string  private _symbol   = \"BPT\";\n    uint8   private _decimals = 18;\n\n    function name() public view returns (string memory) {\n        return _name;\n    }\n\n    function symbol() public view returns (string memory) {\n        return _symbol;\n    }\n\n    function decimals() public view returns(uint8) {\n        return _decimals;\n    }\n\n    function allowance(address src, address dst) external view returns (uint) {\n        return _allowance[src][dst];\n    }\n\n    function balanceOf(address whom) external view returns (uint) {\n        return _balance[whom];\n    }\n\n    function totalSupply() public view returns (uint) {\n        return _totalSupply;\n    }\n\n    function approve(address dst, uint amt) external returns (bool) {\n        _allowance[msg.sender][dst] = amt;\n        emit Approval(msg.sender, dst, amt);\n        return true;\n    }\n\n    function increaseApproval(address dst, uint amt) external returns (bool) {\n        _allowance[msg.sender][dst] = badd(_allowance[msg.sender][dst], amt);\n        emit Approval(msg.sender, dst, _allowance[msg.sender][dst]);\n        return true;\n    }\n\n    function decreaseApproval(address dst, uint amt) external returns (bool) {\n        uint oldValue = _allowance[msg.sender][dst];\n        if (amt \u003e oldValue) {\n            _allowance[msg.sender][dst] = 0;\n        } else {\n            _allowance[msg.sender][dst] = bsub(oldValue, amt);\n        }\n        emit Approval(msg.sender, dst, _allowance[msg.sender][dst]);\n        return true;\n    }\n\n    function transfer(address dst, uint amt) external returns (bool) {\n        _move(msg.sender, dst, amt);\n        return true;\n    }\n\n    function transferFrom(address src, address dst, uint amt) external returns (bool) {\n        require(msg.sender == src || amt \u003c= _allowance[src][msg.sender], \"ERR_BTOKEN_BAD_CALLER\");\n        _move(src, dst, amt);\n        if (msg.sender != src \u0026\u0026 _allowance[src][msg.sender] != uint256(-1)) {\n            _allowance[src][msg.sender] = bsub(_allowance[src][msg.sender], amt);\n            emit Approval(msg.sender, dst, _allowance[src][msg.sender]);\n        }\n        return true;\n    }\n}\n"}}

// hevm: flattened sources of /nix/store/8xb41r4qd0cjb63wcrxf1qmfg88p0961-dss-6fd7de0/src/dai.sol
pragma solidity =0.5.12;

////// /nix/store/8xb41r4qd0cjb63wcrxf1qmfg88p0961-dss-6fd7de0/src/lib.sol
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.

// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

/* pragma solidity 0.5.12; */

contract LibNote {
    event LogNote(
        bytes4   indexed  sig,
        address  indexed  usr,
        bytes32  indexed  arg1,
        bytes32  indexed  arg2,
        bytes             data
    ) anonymous;

    modifier note {
        _;
        assembly {
            // log an 'anonymous' event with a constant 6 words of calldata
            // and four indexed topics: selector, caller, arg1 and arg2
            let mark := msize                         // end of memory ensures zero
            mstore(0x40, add(mark, 288))              // update free memory pointer
            mstore(mark, 0x20)                        // bytes type data offset
            mstore(add(mark, 0x20), 224)              // bytes size (padded)
            calldatacopy(add(mark, 0x40), 0, 224)     // bytes payload
            log4(mark, 288,                           // calldata
                 shl(224, shr(224, calldataload(0))), // msg.sig
                 caller,                              // msg.sender
                 calldataload(4),                     // arg1
                 calldataload(36)                     // arg2
                )
        }
    }
}

////// /nix/store/8xb41r4qd0cjb63wcrxf1qmfg88p0961-dss-6fd7de0/src/dai.sol
// Copyright (C) 2017, 2018, 2019 dbrock, rain, mrchico

// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with this program.  If not, see <https://www.gnu.org/licenses/>.

/* pragma solidity 0.5.12; */

/* import "./lib.sol"; */

contract Dai is LibNote {
    // --- Auth ---
    mapping (address => uint) public wards;
    function rely(address guy) external note auth { wards[guy] = 1; }
    function deny(address guy) external note auth { wards[guy] = 0; }
    modifier auth {
        require(wards[msg.sender] == 1, "Dai/not-authorized");
        _;
    }

    // --- ERC20 Data ---
    string  public constant name     = "Dai Stablecoin";
    string  public constant symbol   = "DAI";
    string  public constant version  = "1";
    uint8   public constant decimals = 18;
    uint256 public totalSupply;

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

    event Approval(address indexed src, address indexed guy, uint wad);
    event Transfer(address indexed src, address indexed dst, uint wad);

    // --- Math ---
    function add(uint x, uint y) internal pure returns (uint z) {
        require((z = x + y) >= x);
    }
    function sub(uint x, uint y) internal pure returns (uint z) {
        require((z = x - y) <= x);
    }

    // --- EIP712 niceties ---
    bytes32 public DOMAIN_SEPARATOR;
    // bytes32 public constant PERMIT_TYPEHASH = keccak256("Permit(address holder,address spender,uint256 nonce,uint256 expiry,bool allowed)");
    bytes32 public constant PERMIT_TYPEHASH = 0xea2aa0a1be11a07ed86d755c93467f4f82362b452371d1ba94d1715123511acb;

    constructor(uint256 chainId_) public {
        wards[msg.sender] = 1;
        DOMAIN_SEPARATOR = keccak256(abi.encode(
            keccak256("EIP712Domain(string name,string version,uint256 chainId,address verifyingContract)"),
            keccak256(bytes(name)),
            keccak256(bytes(version)),
            chainId_,
            address(this)
        ));
    }

    // --- Token ---
    function transfer(address dst, uint wad) external returns (bool) {
        return transferFrom(msg.sender, dst, wad);
    }
    function transferFrom(address src, address dst, uint wad)
        public returns (bool)
    {
        require(balanceOf[src] >= wad, "Dai/insufficient-balance");
        if (src != msg.sender && allowance[src][msg.sender] != uint(-1)) {
            require(allowance[src][msg.sender] >= wad, "Dai/insufficient-allowance");
            allowance[src][msg.sender] = sub(allowance[src][msg.sender], wad);
        }
        balanceOf[src] = sub(balanceOf[src], wad);
        balanceOf[dst] = add(balanceOf[dst], wad);
        emit Transfer(src, dst, wad);
        return true;
    }
    function mint(address usr, uint wad) external auth {
        balanceOf[usr] = add(balanceOf[usr], wad);
        totalSupply    = add(totalSupply, wad);
        emit Transfer(address(0), usr, wad);
    }
    function burn(address usr, uint wad) external {
        require(balanceOf[usr] >= wad, "Dai/insufficient-balance");
        if (usr != msg.sender && allowance[usr][msg.sender] != uint(-1)) {
            require(allowance[usr][msg.sender] >= wad, "Dai/insufficient-allowance");
            allowance[usr][msg.sender] = sub(allowance[usr][msg.sender], wad);
        }
        balanceOf[usr] = sub(balanceOf[usr], wad);
        totalSupply    = sub(totalSupply, wad);
        emit Transfer(usr, address(0), wad);
    }
    function approve(address usr, uint wad) external returns (bool) {
        allowance[msg.sender][usr] = wad;
        emit Approval(msg.sender, usr, wad);
        return true;
    }

    // --- Alias ---
    function push(address usr, uint wad) external {
        transferFrom(msg.sender, usr, wad);
    }
    function pull(address usr, uint wad) external {
        transferFrom(usr, msg.sender, wad);
    }
    function move(address src, address dst, uint wad) external {
        transferFrom(src, dst, wad);
    }

    // --- Approve by signature ---
    function permit(address holder, address spender, uint256 nonce, uint256 expiry,
                    bool allowed, uint8 v, bytes32 r, bytes32 s) external
    {
        bytes32 digest =
            keccak256(abi.encodePacked(
                "\x19\x01",
                DOMAIN_SEPARATOR,
                keccak256(abi.encode(PERMIT_TYPEHASH,
                                     holder,
                                     spender,
                                     nonce,
                                     expiry,
                                     allowed))
        ));

        require(holder != address(0), "Dai/invalid-address-0");
        require(holder == ecrecover(digest, v, r, s), "Dai/invalid-permit");
        require(expiry == 0 || now <= expiry, "Dai/permit-expired");
        require(nonce == nonces[holder]++, "Dai/invalid-nonce");
        uint wad = allowed ? uint(-1) : 0;
        allowance[holder][spender] = wad;
        emit Approval(holder, spender, wad);
    }
}