// File: ABDKMath64x64.sol



// SPDX-License-Identifier: BSD-4-Clause
/*
 * ABDK Math 64.64 Smart Contract Library.  Copyright © 2019 by ABDK Consulting.
 * Author: Mikhail Vladimirov <mikhail.vladimirov@gmail.com>
 */
pragma solidity ^0.7.0;

/**
 * Smart contract library of mathematical functions operating with signed
 * 64.64-bit fixed point numbers.  Signed 64.64-bit fixed point number is
 * basically a simple fraction whose numerator is signed 128-bit integer and
 * denominator is 2^64.  As long as denominator is always the same, there is no
 * need to store it, thus in Solidity signed 64.64-bit fixed point numbers are
 * represented by int128 type holding only the numerator.
 */
library ABDKMath64x64 {
  /*
   * Minimum value signed 64.64-bit fixed point number may have. 
   */
  int128 private constant MIN_64x64 = -0x80000000000000000000000000000000;

  /*
   * Maximum value signed 64.64-bit fixed point number may have. 
   */
  int128 private constant MAX_64x64 = 0x7FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF;

  /**
   * Convert signed 256-bit integer number into signed 64.64-bit fixed point
   * number.  Revert on overflow.
   *
   * @param x signed 256-bit integer number
   * @return signed 64.64-bit fixed point number
   */
  function fromInt (int256 x) internal pure returns (int128) {
    require (x >= -0x8000000000000000 && x <= 0x7FFFFFFFFFFFFFFF);
    return int128 (x << 64);
  }

  /**
   * Convert signed 64.64 fixed point number into signed 64-bit integer number
   * rounding down.
   *
   * @param x signed 64.64-bit fixed point number
   * @return signed 64-bit integer number
   */
  function toInt (int128 x) internal pure returns (int64) {
    return int64 (x >> 64);
  }

  /**
   * Convert unsigned 256-bit integer number into signed 64.64-bit fixed point
   * number.  Revert on overflow.
   *
   * @param x unsigned 256-bit integer number
   * @return signed 64.64-bit fixed point number
   */
  function fromUInt (uint256 x) internal pure returns (int128) {
    require (x <= 0x7FFFFFFFFFFFFFFF);
    return int128 (x << 64);
  }

  /**
   * Convert signed 64.64 fixed point number into unsigned 64-bit integer
   * number rounding down.  Revert on underflow.
   *
   * @param x signed 64.64-bit fixed point number
   * @return unsigned 64-bit integer number
   */
  function toUInt (int128 x) internal pure returns (uint64) {
    require (x >= 0);
    return uint64 (x >> 64);
  }

  /**
   * Convert signed 128.128 fixed point number into signed 64.64-bit fixed point
   * number rounding down.  Revert on overflow.
   *
   * @param x signed 128.128-bin fixed point number
   * @return signed 64.64-bit fixed point number
   */
  function from128x128 (int256 x) internal pure returns (int128) {
    int256 result = x >> 64;
    require (result >= MIN_64x64 && result <= MAX_64x64);
    return int128 (result);
  }

  /**
   * Convert signed 64.64 fixed point number into signed 128.128 fixed point
   * number.
   *
   * @param x signed 64.64-bit fixed point number
   * @return signed 128.128 fixed point number
   */
  function to128x128 (int128 x) internal pure returns (int256) {
    return int256 (x) << 64;
  }

  /**
   * Calculate x + y.  Revert on overflow.
   *
   * @param x signed 64.64-bit fixed point number
   * @param y signed 64.64-bit fixed point number
   * @return signed 64.64-bit fixed point number
   */
  function add (int128 x, int128 y) internal pure returns (int128) {
    int256 result = int256(x) + y;
    require (result >= MIN_64x64 && result <= MAX_64x64);
    return int128 (result);
  }

  /**
   * Calculate x - y.  Revert on overflow.
   *
   * @param x signed 64.64-bit fixed point number
   * @param y signed 64.64-bit fixed point number
   * @return signed 64.64-bit fixed point number
   */
  function sub (int128 x, int128 y) internal pure returns (int128) {
    int256 result = int256(x) - y;
    require (result >= MIN_64x64 && result <= MAX_64x64);
    return int128 (result);
  }

  /**
   * Calculate x * y rounding down.  Revert on overflow.
   *
   * @param x signed 64.64-bit fixed point number
   * @param y signed 64.64-bit fixed point number
   * @return signed 64.64-bit fixed point number
   */
  function mul (int128 x, int128 y) internal pure returns (int128) {
    int256 result = int256(x) * y >> 64;
    require (result >= MIN_64x64 && result <= MAX_64x64);
    return int128 (result);
  }

  /**
   * Calculate x * y rounding towards zero, where x is signed 64.64 fixed point
   * number and y is signed 256-bit integer number.  Revert on overflow.
   *
   * @param x signed 64.64 fixed point number
   * @param y signed 256-bit integer number
   * @return signed 256-bit integer number
   */
  function muli (int128 x, int256 y) internal pure returns (int256) {
    if (x == MIN_64x64) {
      require (y >= -0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF &&
        y <= 0x1000000000000000000000000000000000000000000000000);
      return -y << 63;
    } else {
      bool negativeResult = false;
      if (x < 0) {
        x = -x;
        negativeResult = true;
      }
      if (y < 0) {
        y = -y; // We rely on overflow behavior here
        negativeResult = !negativeResult;
      }
      uint256 absoluteResult = mulu (x, uint256 (y));
      if (negativeResult) {
        require (absoluteResult <=
          0x8000000000000000000000000000000000000000000000000000000000000000);
        return -int256 (absoluteResult); // We rely on overflow behavior here
      } else {
        require (absoluteResult <=
          0x7FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF);
        return int256 (absoluteResult);
      }
    }
  }

  /**
   * Calculate x * y rounding down, where x is signed 64.64 fixed point number
   * and y is unsigned 256-bit integer number.  Revert on overflow.
   *
   * @param x signed 64.64 fixed point number
   * @param y unsigned 256-bit integer number
   * @return unsigned 256-bit integer number
   */
  function mulu (int128 x, uint256 y) internal pure returns (uint256) {
    if (y == 0) return 0;

    require (x >= 0);

    uint256 lo = (uint256 (x) * (y & 0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF)) >> 64;
    uint256 hi = uint256 (x) * (y >> 128);

    require (hi <= 0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF);
    hi <<= 64;

    require (hi <=
      0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF - lo);
    return hi + lo;
  }

  /**
   * Calculate x / y rounding towards zero.  Revert on overflow or when y is
   * zero.
   *
   * @param x signed 64.64-bit fixed point number
   * @param y signed 64.64-bit fixed point number
   * @return signed 64.64-bit fixed point number
   */
  function div (int128 x, int128 y) internal pure returns (int128) {
    require (y != 0);
    int256 result = (int256 (x) << 64) / y;
    require (result >= MIN_64x64 && result <= MAX_64x64);
    return int128 (result);
  }

  /**
   * Calculate x / y rounding towards zero, where x and y are signed 256-bit
   * integer numbers.  Revert on overflow or when y is zero.
   *
   * @param x signed 256-bit integer number
   * @param y signed 256-bit integer number
   * @return signed 64.64-bit fixed point number
   */
  function divi (int256 x, int256 y) internal pure returns (int128) {
    require (y != 0);

    bool negativeResult = false;
    if (x < 0) {
      x = -x; // We rely on overflow behavior here
      negativeResult = true;
    }
    if (y < 0) {
      y = -y; // We rely on overflow behavior here
      negativeResult = !negativeResult;
    }
    uint128 absoluteResult = divuu (uint256 (x), uint256 (y));
    if (negativeResult) {
      require (absoluteResult <= 0x80000000000000000000000000000000);
      return -int128 (absoluteResult); // We rely on overflow behavior here
    } else {
      require (absoluteResult <= 0x7FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF);
      return int128 (absoluteResult); // We rely on overflow behavior here
    }
  }

  /**
   * Calculate x / y rounding towards zero, where x and y are unsigned 256-bit
   * integer numbers.  Revert on overflow or when y is zero.
   *
   * @param x unsigned 256-bit integer number
   * @param y unsigned 256-bit integer number
   * @return signed 64.64-bit fixed point number
   */
  function divu (uint256 x, uint256 y) internal pure returns (int128) {
    require (y != 0);
    uint128 result = divuu (x, y);
    require (result <= uint128 (MAX_64x64));
    return int128 (result);
  }

  /**
   * Calculate -x.  Revert on overflow.
   *
   * @param x signed 64.64-bit fixed point number
   * @return signed 64.64-bit fixed point number
   */
  function neg (int128 x) internal pure returns (int128) {
    require (x != MIN_64x64);
    return -x;
  }

  /**
   * Calculate |x|.  Revert on overflow.
   *
   * @param x signed 64.64-bit fixed point number
   * @return signed 64.64-bit fixed point number
   */
  function abs (int128 x) internal pure returns (int128) {
    require (x != MIN_64x64);
    return x < 0 ? -x : x;
  }

  /**
   * Calculate 1 / x rounding towards zero.  Revert on overflow or when x is
   * zero.
   *
   * @param x signed 64.64-bit fixed point number
   * @return signed 64.64-bit fixed point number
   */
  function inv (int128 x) internal pure returns (int128) {
    require (x != 0);
    int256 result = int256 (0x100000000000000000000000000000000) / x;
    require (result >= MIN_64x64 && result <= MAX_64x64);
    return int128 (result);
  }

  /**
   * Calculate arithmetics average of x and y, i.e. (x + y) / 2 rounding down.
   *
   * @param x signed 64.64-bit fixed point number
   * @param y signed 64.64-bit fixed point number
   * @return signed 64.64-bit fixed point number
   */
  function avg (int128 x, int128 y) internal pure returns (int128) {
    return int128 ((int256 (x) + int256 (y)) >> 1);
  }

  /**
   * Calculate geometric average of x and y, i.e. sqrt (x * y) rounding down.
   * Revert on overflow or in case x * y is negative.
   *
   * @param x signed 64.64-bit fixed point number
   * @param y signed 64.64-bit fixed point number
   * @return signed 64.64-bit fixed point number
   */
  function gavg (int128 x, int128 y) internal pure returns (int128) {
    int256 m = int256 (x) * int256 (y);
    require (m >= 0);
    require (m <
        0x4000000000000000000000000000000000000000000000000000000000000000);
    return int128 (sqrtu (uint256 (m)));
  }

  /**
   * Calculate x^y assuming 0^0 is 1, where x is signed 64.64 fixed point number
   * and y is unsigned 256-bit integer number.  Revert on overflow.
   *
   * @param x signed 64.64-bit fixed point number
   * @param y uint256 value
   * @return signed 64.64-bit fixed point number
   */
  function pow (int128 x, uint256 y) internal pure returns (int128) {
    uint256 absoluteResult;
    bool negativeResult = false;
    if (x >= 0) {
      absoluteResult = powu (uint256 (x) << 63, y);
    } else {
      // We rely on overflow behavior here
      absoluteResult = powu (uint256 (uint128 (-x)) << 63, y);
      negativeResult = y & 1 > 0;
    }

    absoluteResult >>= 63;

    if (negativeResult) {
      require (absoluteResult <= 0x80000000000000000000000000000000);
      return -int128 (absoluteResult); // We rely on overflow behavior here
    } else {
      require (absoluteResult <= 0x7FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF);
      return int128 (absoluteResult); // We rely on overflow behavior here
    }
  }

  /**
   * Calculate sqrt (x) rounding down.  Revert if x < 0.
   *
   * @param x signed 64.64-bit fixed point number
   * @return signed 64.64-bit fixed point number
   */
  function sqrt (int128 x) internal pure returns (int128) {
    require (x >= 0);
    return int128 (sqrtu (uint256 (x) << 64));
  }

  /**
   * Calculate binary logarithm of x.  Revert if x <= 0.
   *
   * @param x signed 64.64-bit fixed point number
   * @return signed 64.64-bit fixed point number
   */
  function log_2 (int128 x) internal pure returns (int128) {
    require (x > 0);

    int256 msb = 0;
    int256 xc = x;
    if (xc >= 0x10000000000000000) { xc >>= 64; msb += 64; }
    if (xc >= 0x100000000) { xc >>= 32; msb += 32; }
    if (xc >= 0x10000) { xc >>= 16; msb += 16; }
    if (xc >= 0x100) { xc >>= 8; msb += 8; }
    if (xc >= 0x10) { xc >>= 4; msb += 4; }
    if (xc >= 0x4) { xc >>= 2; msb += 2; }
    if (xc >= 0x2) msb += 1;  // No need to shift xc anymore

    int256 result = msb - 64 << 64;
    uint256 ux = uint256 (x) << uint256 (127 - msb);
    for (int256 bit = 0x8000000000000000; bit > 0; bit >>= 1) {
      ux *= ux;
      uint256 b = ux >> 255;
      ux >>= 127 + b;
      result += bit * int256 (b);
    }

    return int128 (result);
  }

  /**
   * Calculate natural logarithm of x.  Revert if x <= 0.
   *
   * @param x signed 64.64-bit fixed point number
   * @return signed 64.64-bit fixed point number
   */
  function ln (int128 x) internal pure returns (int128) {
    require (x > 0);

    return int128 (
        uint256 (log_2 (x)) * 0xB17217F7D1CF79ABC9E3B39803F2F6AF >> 128);
  }

  /**
   * Calculate binary exponent of x.  Revert on overflow.
   *
   * @param x signed 64.64-bit fixed point number
   * @return signed 64.64-bit fixed point number
   */
  function exp_2 (int128 x) internal pure returns (int128) {
    require (x < 0x400000000000000000); // Overflow

    if (x < -0x400000000000000000) return 0; // Underflow

    uint256 result = 0x80000000000000000000000000000000;

    if (x & 0x8000000000000000 > 0)
      result = result * 0x16A09E667F3BCC908B2FB1366EA957D3E >> 128;
    if (x & 0x4000000000000000 > 0)
      result = result * 0x1306FE0A31B7152DE8D5A46305C85EDEC >> 128;
    if (x & 0x2000000000000000 > 0)
      result = result * 0x1172B83C7D517ADCDF7C8C50EB14A791F >> 128;
    if (x & 0x1000000000000000 > 0)
      result = result * 0x10B5586CF9890F6298B92B71842A98363 >> 128;
    if (x & 0x800000000000000 > 0)
      result = result * 0x1059B0D31585743AE7C548EB68CA417FD >> 128;
    if (x & 0x400000000000000 > 0)
      result = result * 0x102C9A3E778060EE6F7CACA4F7A29BDE8 >> 128;
    if (x & 0x200000000000000 > 0)
      result = result * 0x10163DA9FB33356D84A66AE336DCDFA3F >> 128;
    if (x & 0x100000000000000 > 0)
      result = result * 0x100B1AFA5ABCBED6129AB13EC11DC9543 >> 128;
    if (x & 0x80000000000000 > 0)
      result = result * 0x10058C86DA1C09EA1FF19D294CF2F679B >> 128;
    if (x & 0x40000000000000 > 0)
      result = result * 0x1002C605E2E8CEC506D21BFC89A23A00F >> 128;
    if (x & 0x20000000000000 > 0)
      result = result * 0x100162F3904051FA128BCA9C55C31E5DF >> 128;
    if (x & 0x10000000000000 > 0)
      result = result * 0x1000B175EFFDC76BA38E31671CA939725 >> 128;
    if (x & 0x8000000000000 > 0)
      result = result * 0x100058BA01FB9F96D6CACD4B180917C3D >> 128;
    if (x & 0x4000000000000 > 0)
      result = result * 0x10002C5CC37DA9491D0985C348C68E7B3 >> 128;
    if (x & 0x2000000000000 > 0)
      result = result * 0x1000162E525EE054754457D5995292026 >> 128;
    if (x & 0x1000000000000 > 0)
      result = result * 0x10000B17255775C040618BF4A4ADE83FC >> 128;
    if (x & 0x800000000000 > 0)
      result = result * 0x1000058B91B5BC9AE2EED81E9B7D4CFAB >> 128;
    if (x & 0x400000000000 > 0)
      result = result * 0x100002C5C89D5EC6CA4D7C8ACC017B7C9 >> 128;
    if (x & 0x200000000000 > 0)
      result = result * 0x10000162E43F4F831060E02D839A9D16D >> 128;
    if (x & 0x100000000000 > 0)
      result = result * 0x100000B1721BCFC99D9F890EA06911763 >> 128;
    if (x & 0x80000000000 > 0)
      result = result * 0x10000058B90CF1E6D97F9CA14DBCC1628 >> 128;
    if (x & 0x40000000000 > 0)
      result = result * 0x1000002C5C863B73F016468F6BAC5CA2B >> 128;
    if (x & 0x20000000000 > 0)
      result = result * 0x100000162E430E5A18F6119E3C02282A5 >> 128;
    if (x & 0x10000000000 > 0)
      result = result * 0x1000000B1721835514B86E6D96EFD1BFE >> 128;
    if (x & 0x8000000000 > 0)
      result = result * 0x100000058B90C0B48C6BE5DF846C5B2EF >> 128;
    if (x & 0x4000000000 > 0)
      result = result * 0x10000002C5C8601CC6B9E94213C72737A >> 128;
    if (x & 0x2000000000 > 0)
      result = result * 0x1000000162E42FFF037DF38AA2B219F06 >> 128;
    if (x & 0x1000000000 > 0)
      result = result * 0x10000000B17217FBA9C739AA5819F44F9 >> 128;
    if (x & 0x800000000 > 0)
      result = result * 0x1000000058B90BFCDEE5ACD3C1CEDC823 >> 128;
    if (x & 0x400000000 > 0)
      result = result * 0x100000002C5C85FE31F35A6A30DA1BE50 >> 128;
    if (x & 0x200000000 > 0)
      result = result * 0x10000000162E42FF0999CE3541B9FFFCF >> 128;
    if (x & 0x100000000 > 0)
      result = result * 0x100000000B17217F80F4EF5AADDA45554 >> 128;
    if (x & 0x80000000 > 0)
      result = result * 0x10000000058B90BFBF8479BD5A81B51AD >> 128;
    if (x & 0x40000000 > 0)
      result = result * 0x1000000002C5C85FDF84BD62AE30A74CC >> 128;
    if (x & 0x20000000 > 0)
      result = result * 0x100000000162E42FEFB2FED257559BDAA >> 128;
    if (x & 0x10000000 > 0)
      result = result * 0x1000000000B17217F7D5A7716BBA4A9AE >> 128;
    if (x & 0x8000000 > 0)
      result = result * 0x100000000058B90BFBE9DDBAC5E109CCE >> 128;
    if (x & 0x4000000 > 0)
      result = result * 0x10000000002C5C85FDF4B15DE6F17EB0D >> 128;
    if (x & 0x2000000 > 0)
      result = result * 0x1000000000162E42FEFA494F1478FDE05 >> 128;
    if (x & 0x1000000 > 0)
      result = result * 0x10000000000B17217F7D20CF927C8E94C >> 128;
    if (x & 0x800000 > 0)
      result = result * 0x1000000000058B90BFBE8F71CB4E4B33D >> 128;
    if (x & 0x400000 > 0)
      result = result * 0x100000000002C5C85FDF477B662B26945 >> 128;
    if (x & 0x200000 > 0)
      result = result * 0x10000000000162E42FEFA3AE53369388C >> 128;
    if (x & 0x100000 > 0)
      result = result * 0x100000000000B17217F7D1D351A389D40 >> 128;
    if (x & 0x80000 > 0)
      result = result * 0x10000000000058B90BFBE8E8B2D3D4EDE >> 128;
    if (x & 0x40000 > 0)
      result = result * 0x1000000000002C5C85FDF4741BEA6E77E >> 128;
    if (x & 0x20000 > 0)
      result = result * 0x100000000000162E42FEFA39FE95583C2 >> 128;
    if (x & 0x10000 > 0)
      result = result * 0x1000000000000B17217F7D1CFB72B45E1 >> 128;
    if (x & 0x8000 > 0)
      result = result * 0x100000000000058B90BFBE8E7CC35C3F0 >> 128;
    if (x & 0x4000 > 0)
      result = result * 0x10000000000002C5C85FDF473E242EA38 >> 128;
    if (x & 0x2000 > 0)
      result = result * 0x1000000000000162E42FEFA39F02B772C >> 128;
    if (x & 0x1000 > 0)
      result = result * 0x10000000000000B17217F7D1CF7D83C1A >> 128;
    if (x & 0x800 > 0)
      result = result * 0x1000000000000058B90BFBE8E7BDCBE2E >> 128;
    if (x & 0x400 > 0)
      result = result * 0x100000000000002C5C85FDF473DEA871F >> 128;
    if (x & 0x200 > 0)
      result = result * 0x10000000000000162E42FEFA39EF44D91 >> 128;
    if (x & 0x100 > 0)
      result = result * 0x100000000000000B17217F7D1CF79E949 >> 128;
    if (x & 0x80 > 0)
      result = result * 0x10000000000000058B90BFBE8E7BCE544 >> 128;
    if (x & 0x40 > 0)
      result = result * 0x1000000000000002C5C85FDF473DE6ECA >> 128;
    if (x & 0x20 > 0)
      result = result * 0x100000000000000162E42FEFA39EF366F >> 128;
    if (x & 0x10 > 0)
      result = result * 0x1000000000000000B17217F7D1CF79AFA >> 128;
    if (x & 0x8 > 0)
      result = result * 0x100000000000000058B90BFBE8E7BCD6D >> 128;
    if (x & 0x4 > 0)
      result = result * 0x10000000000000002C5C85FDF473DE6B2 >> 128;
    if (x & 0x2 > 0)
      result = result * 0x1000000000000000162E42FEFA39EF358 >> 128;
    if (x & 0x1 > 0)
      result = result * 0x10000000000000000B17217F7D1CF79AB >> 128;

    result >>= uint256 (63 - (x >> 64));
    require (result <= uint256 (MAX_64x64));

    return int128 (result);
  }

  /**
   * Calculate natural exponent of x.  Revert on overflow.
   *
   * @param x signed 64.64-bit fixed point number
   * @return signed 64.64-bit fixed point number
   */
  function exp (int128 x) internal pure returns (int128) {
    require (x < 0x400000000000000000); // Overflow

    if (x < -0x400000000000000000) return 0; // Underflow

    return exp_2 (
        int128 (int256 (x) * 0x171547652B82FE1777D0FFDA0D23A7D12 >> 128));
  }

  /**
   * Calculate x / y rounding towards zero, where x and y are unsigned 256-bit
   * integer numbers.  Revert on overflow or when y is zero.
   *
   * @param x unsigned 256-bit integer number
   * @param y unsigned 256-bit integer number
   * @return unsigned 64.64-bit fixed point number
   */
  function divuu (uint256 x, uint256 y) private pure returns (uint128) {
    require (y != 0);

    uint256 result;

    if (x <= 0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF)
      result = (x << 64) / y;
    else {
      uint256 msb = 192;
      uint256 xc = x >> 192;
      if (xc >= 0x100000000) { xc >>= 32; msb += 32; }
      if (xc >= 0x10000) { xc >>= 16; msb += 16; }
      if (xc >= 0x100) { xc >>= 8; msb += 8; }
      if (xc >= 0x10) { xc >>= 4; msb += 4; }
      if (xc >= 0x4) { xc >>= 2; msb += 2; }
      if (xc >= 0x2) msb += 1;  // No need to shift xc anymore

      result = (x << 255 - msb) / ((y - 1 >> msb - 191) + 1);
      require (result <= 0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF);

      uint256 hi = result * (y >> 128);
      uint256 lo = result * (y & 0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF);

      uint256 xh = x >> 192;
      uint256 xl = x << 64;

      if (xl < lo) xh -= 1;
      xl -= lo; // We rely on overflow behavior here
      lo = hi << 128;
      if (xl < lo) xh -= 1;
      xl -= lo; // We rely on overflow behavior here

      assert (xh == hi >> 128);

      result += xl / y;
    }

    require (result <= 0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF);
    return uint128 (result);
  }

  /**
   * Calculate x^y assuming 0^0 is 1, where x is unsigned 129.127 fixed point
   * number and y is unsigned 256-bit integer number.  Revert on overflow.
   *
   * @param x unsigned 129.127-bit fixed point number
   * @param y uint256 value
   * @return unsigned 129.127-bit fixed point number
   */
  function powu (uint256 x, uint256 y) private pure returns (uint256) {
    if (y == 0) return 0x80000000000000000000000000000000;
    else if (x == 0) return 0;
    else {
      int256 msb = 0;
      uint256 xc = x;
      if (xc >= 0x100000000000000000000000000000000) { xc >>= 128; msb += 128; }
      if (xc >= 0x10000000000000000) { xc >>= 64; msb += 64; }
      if (xc >= 0x100000000) { xc >>= 32; msb += 32; }
      if (xc >= 0x10000) { xc >>= 16; msb += 16; }
      if (xc >= 0x100) { xc >>= 8; msb += 8; }
      if (xc >= 0x10) { xc >>= 4; msb += 4; }
      if (xc >= 0x4) { xc >>= 2; msb += 2; }
      if (xc >= 0x2) msb += 1;  // No need to shift xc anymore

      int256 xe = msb - 127;
      if (xe > 0) x >>= uint256 (xe);
      else x <<= uint256 (-xe);

      uint256 result = 0x80000000000000000000000000000000;
      int256 re = 0;

      while (y > 0) {
        if (y & 1 > 0) {
          result = result * x;
          y -= 1;
          re += xe;
          if (result >=
            0x8000000000000000000000000000000000000000000000000000000000000000) {
            result >>= 128;
            re += 1;
          } else result >>= 127;
          if (re < -127) return 0; // Underflow
          require (re < 128); // Overflow
        } else {
          x = x * x;
          y >>= 1;
          xe <<= 1;
          if (x >=
            0x8000000000000000000000000000000000000000000000000000000000000000) {
            x >>= 128;
            xe += 1;
          } else x >>= 127;
          if (xe < -127) return 0; // Underflow
          require (xe < 128); // Overflow
        }
      }

      if (re > 0) result <<= uint256 (re);
      else if (re < 0) result >>= uint256 (-re);

      return result;
    }
  }

  /**
   * Calculate sqrt (x) rounding down, where x is unsigned 256-bit integer
   * number.
   *
   * @param x unsigned 256-bit integer number
   * @return unsigned 128-bit integer number
   */
  function sqrtu (uint256 x) private pure returns (uint128) {
    if (x == 0) return 0;
    else {
      uint256 xx = x;
      uint256 r = 1;
      if (xx >= 0x100000000000000000000000000000000) { xx >>= 128; r <<= 64; }
      if (xx >= 0x10000000000000000) { xx >>= 64; r <<= 32; }
      if (xx >= 0x100000000) { xx >>= 32; r <<= 16; }
      if (xx >= 0x10000) { xx >>= 16; r <<= 8; }
      if (xx >= 0x100) { xx >>= 8; r <<= 4; }
      if (xx >= 0x10) { xx >>= 4; r <<= 2; }
      if (xx >= 0x8) { r <<= 1; }
      r = (r + x / r) >> 1;
      r = (r + x / r) >> 1;
      r = (r + x / r) >> 1;
      r = (r + x / r) >> 1;
      r = (r + x / r) >> 1;
      r = (r + x / r) >> 1;
      r = (r + x / r) >> 1; // Seven iterations should be enough
      uint256 r1 = x / r;
      return uint128 (r < r1 ? r : r1);
    }
  }
}
// File: Address.sol



// SPDX-License-Identifier: MIT

pragma solidity >=0.6.2 <0.8.0;

/**
 * @dev Collection of functions related to the address type
 */
library Address {
    /**
     * @dev Returns true if `account` is a contract.
     *
     * [IMPORTANT]
     * ====
     * It is unsafe to assume that an address for which this function returns
     * false is an externally-owned account (EOA) and not a contract.
     *
     * Among others, `isContract` will return false for the following
     * types of addresses:
     *
     *  - an externally-owned account
     *  - a contract in construction
     *  - an address where a contract will be created
     *  - an address where a contract lived, but was destroyed
     * ====
     */
    function isContract(address account) internal view returns (bool) {
        // This method relies on extcodesize, which returns 0 for contracts in
        // construction, since the code is only stored at the end of the
        // constructor execution.

        uint256 size;
        // solhint-disable-next-line no-inline-assembly
        assembly { size := extcodesize(account) }
        return size > 0;
    }

    /**
     * @dev Replacement for Solidity's `transfer`: sends `amount` wei to
     * `recipient`, forwarding all available gas and reverting on errors.
     *
     * https://eips.ethereum.org/EIPS/eip-1884[EIP1884] increases the gas cost
     * of certain opcodes, possibly making contracts go over the 2300 gas limit
     * imposed by `transfer`, making them unable to receive funds via
     * `transfer`. {sendValue} removes this limitation.
     *
     * https://diligence.consensys.net/posts/2019/09/stop-using-soliditys-transfer-now/[Learn more].
     *
     * IMPORTANT: because control is transferred to `recipient`, care must be
     * taken to not create reentrancy vulnerabilities. Consider using
     * {ReentrancyGuard} or the
     * https://solidity.readthedocs.io/en/v0.5.11/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].
     */
    function sendValue(address payable recipient, uint256 amount) internal {
        require(address(this).balance >= amount, "Address: insufficient balance");

        // solhint-disable-next-line avoid-low-level-calls, avoid-call-value
        (bool success, ) = recipient.call{ value: amount }("");
        require(success, "Address: unable to send value, recipient may have reverted");
    }

    /**
     * @dev Performs a Solidity function call using a low level `call`. A
     * plain`call` is an unsafe replacement for a function call: use this
     * function instead.
     *
     * If `target` reverts with a revert reason, it is bubbled up by this
     * function (like regular Solidity function calls).
     *
     * Returns the raw returned data. To convert to the expected return value,
     * use https://solidity.readthedocs.io/en/latest/units-and-global-variables.html?highlight=abi.decode#abi-encoding-and-decoding-functions[`abi.decode`].
     *
     * Requirements:
     *
     * - `target` must be a contract.
     * - calling `target` with `data` must not revert.
     *
     * _Available since v3.1._
     */
    function functionCall(address target, bytes memory data) internal returns (bytes memory) {
      return functionCall(target, data, "Address: low-level call failed");
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`], but with
     * `errorMessage` as a fallback revert reason when `target` reverts.
     *
     * _Available since v3.1._
     */
    function functionCall(address target, bytes memory data, string memory errorMessage) internal returns (bytes memory) {
        return functionCallWithValue(target, data, 0, errorMessage);
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but also transferring `value` wei to `target`.
     *
     * Requirements:
     *
     * - the calling contract must have an ETH balance of at least `value`.
     * - the called Solidity function must be `payable`.
     *
     * _Available since v3.1._
     */
    function functionCallWithValue(address target, bytes memory data, uint256 value) internal returns (bytes memory) {
        return functionCallWithValue(target, data, value, "Address: low-level call with value failed");
    }

    /**
     * @dev Same as {xref-Address-functionCallWithValue-address-bytes-uint256-}[`functionCallWithValue`], but
     * with `errorMessage` as a fallback revert reason when `target` reverts.
     *
     * _Available since v3.1._
     */
    function functionCallWithValue(address target, bytes memory data, uint256 value, string memory errorMessage) internal returns (bytes memory) {
        require(address(this).balance >= value, "Address: insufficient balance for call");
        require(isContract(target), "Address: call to non-contract");

        // solhint-disable-next-line avoid-low-level-calls
        (bool success, bytes memory returndata) = target.call{ value: value }(data);
        return _verifyCallResult(success, returndata, errorMessage);
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but performing a static call.
     *
     * _Available since v3.3._
     */
    function functionStaticCall(address target, bytes memory data) internal view returns (bytes memory) {
        return functionStaticCall(target, data, "Address: low-level static call failed");
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
     * but performing a static call.
     *
     * _Available since v3.3._
     */
    function functionStaticCall(address target, bytes memory data, string memory errorMessage) internal view returns (bytes memory) {
        require(isContract(target), "Address: static call to non-contract");

        // solhint-disable-next-line avoid-low-level-calls
        (bool success, bytes memory returndata) = target.staticcall(data);
        return _verifyCallResult(success, returndata, errorMessage);
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but performing a delegate call.
     *
     * _Available since v3.4._
     */
    function functionDelegateCall(address target, bytes memory data) internal returns (bytes memory) {
        return functionDelegateCall(target, data, "Address: low-level delegate call failed");
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
     * but performing a delegate call.
     *
     * _Available since v3.4._
     */
    function functionDelegateCall(address target, bytes memory data, string memory errorMessage) internal returns (bytes memory) {
        require(isContract(target), "Address: delegate call to non-contract");

        // solhint-disable-next-line avoid-low-level-calls
        (bool success, bytes memory returndata) = target.delegatecall(data);
        return _verifyCallResult(success, returndata, errorMessage);
    }

    function _verifyCallResult(bool success, bytes memory returndata, string memory errorMessage) private pure returns(bytes memory) {
        if (success) {
            return returndata;
        } else {
            // Look for revert reason and bubble it up if present
            if (returndata.length > 0) {
                // The easiest way to bubble the revert reason is using memory via assembly

                // solhint-disable-next-line no-inline-assembly
                assembly {
                    let returndata_size := mload(returndata)
                    revert(add(32, returndata), returndata_size)
                }
            } else {
                revert(errorMessage);
            }
        }
    }
}

// File: BMIZapper.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.7.3;

import "./ICToken.sol";
import "./IYearn.sol";
import "./ILendingPoolV2.sol";
import "./IBasket.sol";
import "./IATokenV2.sol";
import "./ICurveZap.sol";
import "./ICurve.sol";

import "./ABDKMath64x64.sol";

import "./ERC20.sol";
import "./IERC20.sol";
import "./SafeERC20.sol";
import "./SafeMath.sol";
import "./Ownable.sol";

contract BMIZapper is Ownable {
    using SafeERC20 for IERC20;
    using SafeMath for uint256;

    using ABDKMath64x64 for int128;
    using ABDKMath64x64 for uint256;

    // Auxillery
    address constant AAVE_LENDING_POOL_V2 = 0x7d2768dE32b0b80b7a3454c06BdAc94A69DDc7A9;

    // Tokens

    // BMI
    address public BMI;

    // Bare
    address constant DAI = 0x6B175474E89094C44Da98b954EedeAC495271d0F;
    address constant USDC = 0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48;
    address constant USDT = 0xdAC17F958D2ee523a2206206994597C13D831ec7;
    address constant TUSD = 0x0000000000085d4780B73119b644AE5ecd22b376;
    address constant SUSD = 0x57Ab1ec28D129707052df4dF418D58a2D46d5f51;
    address constant BUSD = 0x4Fabb145d64652a948d72533023f6E7A623C7C53;
    address constant USDP = 0x1456688345527bE1f37E9e627DA0837D6f08C925;
    address constant FRAX = 0x853d955aCEf822Db058eb8505911ED77F175b99e;
    address constant ALUSD = 0xBC6DA0FE9aD5f3b0d58160288917AA56653660E9;
    address constant LUSD = 0x5f98805A4E8be255a32880FDeC7F6728C6568bA0;
    address constant USDN = 0x674C6Ad92Fd080e4004b2312b45f796a192D27a0;

    // Yearn
    address constant yDAI = 0x19D3364A399d251E894aC732651be8B0E4e85001;
    address constant yUSDC = 0x5f18C75AbDAe578b483E5F43f12a39cF75b973a9;
    address constant yUSDT = 0x7Da96a3891Add058AdA2E826306D812C638D87a7;
    address constant yTUSD = 0x37d19d1c4E1fa9DC47bD1eA12f742a0887eDa74a;
    address constant ySUSD = 0xa5cA62D95D24A4a350983D5B8ac4EB8638887396;

    // Yearn CRV
    address constant yCRV = 0x4B5BfD52124784745c1071dcB244C6688d2533d3; // Y Pool
    address constant ycrvSUSD = 0x5a770DbD3Ee6bAF2802D29a901Ef11501C44797A;
    address constant ycrvYBUSD = 0x8ee57c05741aA9DB947A744E713C15d4d19D8822;
    address constant ycrvBUSD = 0x6Ede7F19df5df6EF23bD5B9CeDb651580Bdf56Ca;
    address constant ycrvUSDP = 0xC4dAf3b5e2A9e93861c3FBDd25f1e943B8D87417;
    address constant ycrvFRAX = 0xB4AdA607B9d6b2c9Ee07A275e9616B84AC560139;
    address constant ycrvALUSD = 0xA74d4B67b3368E83797a35382AFB776bAAE4F5C8;
    address constant ycrvLUSD = 0x5fA5B62c8AF877CB37031e0a3B2f34A78e3C56A6;
    address constant ycrvUSDN = 0x3B96d491f067912D18563d56858Ba7d6EC67a6fa;
    address constant ycrvIB = 0x27b7b1ad7288079A66d12350c828D3C00A6F07d7;
    address constant ycrvThree = 0x84E13785B5a27879921D6F685f041421C7F482dA;
    address constant ycrvDUSD = 0x30FCf7c6cDfC46eC237783D94Fc78553E79d4E9C;
    address constant ycrvMUSD = 0x8cc94ccd0f3841a468184aCA3Cc478D2148E1757;
    address constant ycrvUST = 0x1C6a9783F812b3Af3aBbf7de64c3cD7CC7D1af44;

    // Aave
    address constant aDAI = 0x028171bCA77440897B824Ca71D1c56caC55b68A3;
    address constant aUSDC = 0xBcca60bB61934080951369a648Fb03DF4F96263C;
    address constant aUSDT = 0x3Ed3B47Dd13EC9a98b44e6204A523E766B225811;
    address constant aTUSD = 0x101cc05f4A51C0319f570d5E146a8C625198e636;
    address constant aSUSD = 0x6C5024Cd4F8A59110119C56f8933403A539555EB;

    // Compound
    address constant cDAI = 0x5d3a536E4D6DbD6114cc1Ead35777bAB948E3643;
    address constant cUSDC = 0x39AA39c021dfbaE8faC545936693aC917d5E7563;
    address constant cUSDT = 0xf650C3d88D12dB855b8bf7D11Be6C55A4e07dCC9;
    address constant cTUSD = 0x12392F67bdf24faE0AF363c24aC620a2f67DAd86;

    // Curve
    address constant crvY = 0xdF5e0e81Dff6FAF3A7e52BA697820c5e32D806A8;
    address constant crvYPool = 0x45F783CCE6B7FF23B2ab2D70e416cdb7D6055f51;
    address constant crvYZap = 0xbBC81d23Ea2c3ec7e56D39296F0cbB648873a5d3;

    address constant crvSUSD = 0xC25a3A3b969415c80451098fa907EC722572917F;
    address constant crvSUSDPool = 0xA5407eAE9Ba41422680e2e00537571bcC53efBfD;
    address constant crvSUSDZap = 0xFCBa3E75865d2d561BE8D220616520c171F12851;

    address constant crvYBUSD = 0x3B3Ac5386837Dc563660FB6a0937DFAa5924333B;
    address constant crvYBUSDPool = 0x79a8C46DeA5aDa233ABaFFD40F3A0A2B1e5A4F27;
    address constant crvYBUSDZap = 0xb6c057591E073249F2D9D88Ba59a46CFC9B59EdB;

    address constant crvThree = 0x6c3F90f043a72FA612cbac8115EE7e52BDe6E490;
    address constant crvThreePool = 0xbEbc44782C7dB0a1A60Cb6fe97d0b483032FF1C7;

    address constant crvUSDP = 0x7Eb40E450b9655f4B3cC4259BCC731c63ff55ae6;
    address constant crvUSDPPool = 0x42d7025938bEc20B69cBae5A77421082407f053A;
    address constant crvUSDPZap = 0x3c8cAee4E09296800f8D29A68Fa3837e2dae4940;

    address constant crvDUSD = 0x3a664Ab939FD8482048609f652f9a0B0677337B9;
    address constant crvDUSDPool = 0x8038C01A0390a8c547446a0b2c18fc9aEFEcc10c;
    address constant crvDUSDZap = 0x61E10659fe3aa93d036d099405224E4Ac24996d0;

    address constant crvMUSD = 0x1AEf73d49Dedc4b1778d0706583995958Dc862e6;
    address constant crvMUSDPool = 0x8474DdbE98F5aA3179B3B3F5942D724aFcdec9f6;
    address constant crvMUSDZap = 0x803A2B40c5a9BB2B86DD630B274Fa2A9202874C2;

    address constant crvUST = 0x94e131324b6054c0D789b190b2dAC504e4361b53;
    address constant crvUSTPool = 0x890f4e345B1dAED0367A877a1612f86A1f86985f;
    address constant crvUSTZap = 0xB0a0716841F2Fc03fbA72A891B8Bb13584F52F2d;

    address constant crvUSDN = 0x4f3E8F405CF5aFC05D68142F3783bDfE13811522;
    address constant crvUSDNPool = 0x0f9cb53Ebe405d49A0bbdBD291A65Ff571bC83e1;
    address constant crvUSDNZap = 0x094d12e5b541784701FD8d65F11fc0598FBC6332;

    address constant crvIB = 0x5282a4eF67D9C33135340fB3289cc1711c13638C;
    address constant crvIBPool = 0x2dded6Da1BF5DBdF597C45fcFaa3194e53EcfeAF;

    address constant crvBUSD = 0x4807862AA8b2bF68830e4C8dc86D0e9A998e085a;
    address constant crvFRAX = 0xd632f22692FaC7611d2AA1C0D552930D43CAEd3B;
    address constant crvALUSD = 0x43b4FdFD4Ff969587185cDB6f0BD875c5Fc83f8c;
    address constant crvLUSD = 0xEd279fDD11cA84bEef15AF5D39BB4d4bEE23F0cA;

    address constant crvMetaZapper = 0xA79828DF1850E8a3A3064576f380D90aECDD3359;

    // **** Constructor ****

    constructor(address _bmi) {
        BMI = _bmi;
    }

    function recoverERC20(address _token) public onlyOwner {
        IERC20(_token).safeTransfer(msg.sender, IERC20(_token).balanceOf(address(this)));
    }

    // **** View only functions **** //

    // Estimates USDC equilavent for yearn crv and crv pools
    function calcUSDCEquilavent(address _from, uint256 _amount) public view returns (uint256) {
        if (_isYearnCRV(_from)) {
            _amount = _amount.mul(IYearn(_from).pricePerShare()).div(1e18);
            _from = IYearn(_from).token();
        }

        if (_from == crvY || _from == crvSUSD || _from == crvThree || _from == crvYBUSD) {
            address zap = crvYZap;

            if (_from == crvSUSD) {
                zap = crvSUSDZap;
            } else if (_from == crvThree) {
                zap = crvThreePool;
            } else if (_from == crvYBUSD) {
                zap = crvYBUSDZap;
            }

            return ICurveZapSimple(zap).calc_withdraw_one_coin(_amount, 1);
        } else if (_from == crvUSDN || _from == crvUSDP || _from == crvDUSD || _from == crvMUSD || _from == crvUST) {
            address zap = crvUSDNZap;

            if (_from == crvUSDP) {
                zap = crvUSDPZap;
            } else if (_from == crvDUSD) {
                zap = crvDUSDZap;
            } else if (_from == crvMUSD) {
                zap = crvMUSDZap;
            } else if (_from == crvUST) {
                zap = crvUSTZap;
            }

            return ICurveZapSimple(zap).calc_withdraw_one_coin(_amount, 2);
        } else if (_from == crvIB) {
            return ICurveZapSimple(crvIBPool).calc_withdraw_one_coin(_amount, 1, true);
        } else {
            // Meta pools, USDC is 2nd index
            return ICurveZapSimple(crvMetaZapper).calc_withdraw_one_coin(_from, _amount, 2);
        }
    }

    function getUnderlyingAmount(address _derivative, uint256 _amount) public view returns (address, uint256) {
        if (_isAave(_derivative)) {
            return (IATokenV2(_derivative).UNDERLYING_ASSET_ADDRESS(), _amount);
        }

        if (_isCompound(_derivative)) {
            uint256 rate = ICToken(_derivative).exchangeRateStored();
            address underlying = ICToken(_derivative).underlying();
            uint256 underlyingDecimals = ERC20(underlying).decimals();
            uint256 mantissa = 18 + underlyingDecimals - 8;
            uint256 oneCTokenInUnderlying = rate.mul(1e18).div(10**mantissa);
            return (underlying, _amount.mul(oneCTokenInUnderlying).div(1e8));
        }

        // YearnCRV just or CRV return USDC
        if (_isCRV(_derivative) || _isYearnCRV(_derivative)) {
            return (USDC, calcUSDCEquilavent(_derivative, _amount));
        }

        if (_isYearn(_derivative)) {
            _amount = _amount.mul(IYearn(_derivative).pricePerShare()).div(1e18);

            if (_derivative == yDAI) {
                return (DAI, _amount);
            }

            if (_derivative == yUSDC) {
                return (USDC, _amount);
            }

            if (_derivative == yUSDT) {
                return (USDT, _amount);
            }

            if (_derivative == yTUSD) {
                return (TUSD, _amount);
            }

            if (_derivative == ySUSD) {
                return (SUSD, _amount);
            }
        }

        return (_derivative, _amount);
    }

    // **** Stateful functions ****

    function zapToBMI(
        address _from,
        uint256 _amount,
        address _fromUnderlying,
        uint256 _fromUnderlyingAmount,
        uint256 _minBMIRecv,
        address[] memory _bmiConstituents,
        uint256[] memory _bmiConstituentsWeightings,
        address _aggregator,
        bytes memory _aggregatorData
    ) public returns (uint256) {
        uint256 sum = 0;
        for (uint256 i = 0; i < _bmiConstituentsWeightings.length; i++) {
            sum = sum.add(_bmiConstituentsWeightings[i]);
        }

        // Sum should be between 0.999 and 1.000
        assert(sum <= 1e18);
        assert(sum >= 999e15);

        // Transfer to contract
        IERC20(_from).safeTransferFrom(msg.sender, address(this), _amount);

        // Primitive
        if (_isBare(_from)) {
            _primitiveToBMI(_from, _amount, _bmiConstituents, _bmiConstituentsWeightings, _aggregator, _aggregatorData);
        }
        // Yearn (primitive)
        else if (_isYearn(_from)) {
            IYearn(_from).withdraw();
            _primitiveToBMI(
                _fromUnderlying,
                _fromUnderlyingAmount,
                _bmiConstituents,
                _bmiConstituentsWeightings,
                _aggregator,
                _aggregatorData
            );
        }
        // Yearn (primitive)
        else if (_isYearnCRV(_from)) {
            IYearn(_from).withdraw();
            address crvToken = IYearn(_from).token();
            _crvToPrimitive(crvToken, IERC20(crvToken).balanceOf(address(this)));
            _primitiveToBMI(
                USDC,
                IERC20(USDC).balanceOf(address(this)),
                _bmiConstituents,
                _bmiConstituentsWeightings,
                address(0),
                ""
            );
        }
        // Compound
        else if (_isCompound(_from)) {
            require(ICToken(_from).redeem(_amount) == 0, "!ctoken-redeem");
            _primitiveToBMI(
                _fromUnderlying,
                _fromUnderlyingAmount,
                _bmiConstituents,
                _bmiConstituentsWeightings,
                _aggregator,
                _aggregatorData
            );
        }
        // Aave
        else if (_isAave(_from)) {
            IERC20(_from).safeApprove(AAVE_LENDING_POOL_V2, 0);
            IERC20(_from).safeApprove(AAVE_LENDING_POOL_V2, _amount);
            ILendingPoolV2(AAVE_LENDING_POOL_V2).withdraw(_fromUnderlying, type(uint256).max, address(this));

            _primitiveToBMI(
                _fromUnderlying,
                _fromUnderlyingAmount,
                _bmiConstituents,
                _bmiConstituentsWeightings,
                _aggregator,
                _aggregatorData
            );
        }
        // Curve
        else {
            _crvToPrimitive(_from, _amount);
            _primitiveToBMI(
                USDC,
                IERC20(USDC).balanceOf(address(this)),
                _bmiConstituents,
                _bmiConstituentsWeightings,
                address(0),
                ""
            );
        }

        // Checks
        uint256 _bmiBal = IERC20(BMI).balanceOf(address(this));
        require(_bmiBal >= _minBMIRecv, "!min-mint");
        IERC20(BMI).safeTransfer(msg.sender, _bmiBal);

        return _bmiBal;
    }

    // **** Internal helpers ****

    function _crvToPrimitive(address _from, uint256 _amount) internal {
        // Remove via zap to USDC
        if (_from == crvY || _from == crvSUSD || _from == crvYBUSD) {
            address zap = crvYZap;

            if (_from == crvSUSD) {
                zap = crvSUSDZap;
            } else if (_from == crvYBUSD) {
                zap = crvYBUSDZap;
            }

            IERC20(_from).safeApprove(zap, 0);
            IERC20(_from).safeApprove(zap, _amount);
            ICurveZapSimple(zap).remove_liquidity_one_coin(_amount, 1, 0, false);
        } else if (_from == crvUSDP || _from == crvUSDN || _from == crvDUSD || _from == crvMUSD || _from == crvUST) {
            address zap = crvUSDNZap;

            if (_from == crvUSDP) {
                zap = crvUSDPZap;
            } else if (_from == crvDUSD) {
                zap = crvDUSDZap;
            } else if (_from == crvMUSD) {
                zap = crvMUSDZap;
            } else if (_from == crvUST) {
                zap = crvUSTZap;
            }

            IERC20(_from).safeApprove(zap, 0);
            IERC20(_from).safeApprove(zap, _amount);
            ICurveZapSimple(zap).remove_liquidity_one_coin(_amount, 2, 0);
        } else if (_from == crvIB) {
            IERC20(_from).safeApprove(crvIBPool, 0);
            IERC20(_from).safeApprove(crvIBPool, _amount);
            ICurveZapSimple(crvIBPool).remove_liquidity_one_coin(_amount, 1, 0, true);
        } else if (_from == crvThree) {
            address zap = crvThreePool;

            IERC20(_from).safeApprove(zap, 0);
            IERC20(_from).safeApprove(zap, _amount);
            ICurveZapSimple(zap).remove_liquidity_one_coin(_amount, 1, 0);
        } else {
            // Meta pools, USDC is 2nd index
            IERC20(_from).safeApprove(crvMetaZapper, 0);
            IERC20(_from).safeApprove(crvMetaZapper, _amount);
            ICurveZapSimple(crvMetaZapper).remove_liquidity_one_coin(_from, _amount, 2, 0, address(this));
        }
    }

    function _primitiveToBMI(
        address _token,
        uint256 _amount,
        address[] memory _bmiConstituents,
        uint256[] memory _bmiConstituentsWeightings,
        address _aggregator,
        bytes memory _aggregatorData
    ) internal {
        // Offset, DAI = 0, USDC = 1, USDT = 2
        uint256 offset = 0;

        // Primitive to USDC (if not already USDC)
        if (_token != DAI && _token != USDC && _token != USDT) {
            IERC20(_token).safeApprove(_aggregator, 0);
            IERC20(_token).safeApprove(_aggregator, _amount);

            (bool success, ) = _aggregator.call(_aggregatorData);
            require(success, "!swap");

            // Always goes to USDC
            // If we swapping
            _token = USDC;
        }

        if (_token == USDC) {
            offset = 1;
        } else if (_token == USDT) {
            offset = 2;
        }

        // Amount to mint
        uint256 amountToMint;
        uint256 bmiSupply = IERC20(BMI).totalSupply();

        uint256 tokenBal = IERC20(_token).balanceOf(address(this));
        uint256 tokenAmount;
        for (uint256 i = 0; i < _bmiConstituents.length; i++) {
            // Weighting of the token for BMI constituient
            tokenAmount = tokenBal.mul(_bmiConstituentsWeightings[i]).div(1e18);
            _toBMIConstituent(_token, _bmiConstituents[i], tokenAmount, offset);

            // Get amount to Mint
            amountToMint = _approveBMIAndGetMintableAmount(bmiSupply, _bmiConstituents[i], amountToMint);
        }

        IBasket(BMI).mint(amountToMint);
    }

    function _approveBMIAndGetMintableAmount(
        uint256 _bmiTotalSupply,
        address _bmiConstituient,
        uint256 _curMintAmount
    ) internal returns (uint256) {
        uint256 bal = IERC20(_bmiConstituient).balanceOf(address(this));
        uint256 bmiBal = IERC20(_bmiConstituient).balanceOf(BMI);

        IERC20(_bmiConstituient).safeApprove(BMI, 0);
        IERC20(_bmiConstituient).safeApprove(BMI, bal);

        // Calculate how much BMI we can mint at max
        // Formula: min(e for e in bmiSupply * tokenWeHave[e] / tokenInBMI[e])
        if (_curMintAmount == 0) {
            return _bmiTotalSupply.mul(bal).div(bmiBal);
        }

        uint256 temp = _bmiTotalSupply.mul(bal).div(bmiBal);
        if (temp < _curMintAmount) {
            return temp;
        }

        return _curMintAmount;
    }

    function _toBMIConstituent(
        address _fromToken,
        address _toToken,
        uint256 _amount,
        uint256 _curveOffset
    ) internal {
        uint256 bal;
        uint256[4] memory depositAmounts4 = [uint256(0), uint256(0), uint256(0), uint256(0)];

        if (_toToken == ySUSD) {
            IERC20(_fromToken).safeApprove(crvSUSDPool, 0);
            IERC20(_fromToken).safeApprove(crvSUSDPool, _amount);

            ICurvePool(crvSUSDPool).exchange(int128(_curveOffset), 3, _amount, 0);

            bal = IERC20(SUSD).balanceOf(address(this));
            IERC20(SUSD).safeApprove(ySUSD, 0);
            IERC20(SUSD).safeApprove(ySUSD, bal);
        }
        // Gen 1 pools
        else if (
            _toToken == yCRV ||
            _toToken == ycrvSUSD ||
            _toToken == ycrvYBUSD ||
            _toToken == ycrvUSDN ||
            _toToken == ycrvUSDP ||
            _toToken == ycrvDUSD ||
            _toToken == ycrvMUSD ||
            _toToken == ycrvUST
        ) {
            address crvToken = IYearn(_toToken).token();

            address zap = crvYZap;
            if (_toToken == ycrvSUSD) {
                zap = crvSUSDZap;
            } else if (_toToken == ycrvYBUSD) {
                zap = crvYBUSDZap;
            } else if (_toToken == ycrvUSDN) {
                zap = crvUSDNZap;
                _curveOffset += 1;
            } else if (_toToken == ycrvUSDP) {
                zap = crvUSDPZap;
                _curveOffset += 1;
            } else if (_toToken == ycrvDUSD) {
                zap = crvDUSDZap;
                _curveOffset += 1;
            } else if (_toToken == ycrvMUSD) {
                zap = crvMUSDZap;
                _curveOffset += 1;
            } else if (_toToken == ycrvUST) {
                zap = crvUSTZap;
                _curveOffset += 1;
            }

            depositAmounts4[_curveOffset] = _amount;
            IERC20(_fromToken).safeApprove(zap, 0);
            IERC20(_fromToken).safeApprove(zap, _amount);
            ICurveZapSimple(zap).add_liquidity(depositAmounts4, 0);

            bal = IERC20(crvToken).balanceOf(address(this));
            IERC20(crvToken).safeApprove(_toToken, 0);
            IERC20(crvToken).safeApprove(_toToken, bal);
        } else if (_toToken == ycrvThree || _toToken == ycrvIB) {
            address crvToken = IYearn(_toToken).token();

            uint256[3] memory depositAmounts3 = [uint256(0), uint256(0), uint256(0)];
            depositAmounts3[_curveOffset] = _amount;

            address zap = crvThreePool;
            if (_toToken == ycrvIB) {
                zap = crvIBPool;
            }

            IERC20(_fromToken).safeApprove(zap, 0);
            IERC20(_fromToken).safeApprove(zap, _amount);

            if (_toToken == ycrvThree) {
                ICurveZapSimple(zap).add_liquidity(depositAmounts3, 0);
            } else {
                ICurveZapSimple(zap).add_liquidity(depositAmounts3, 0, true);
            }

            bal = IERC20(crvToken).balanceOf(address(this));
            IERC20(crvToken).safeApprove(_toToken, 0);
            IERC20(crvToken).safeApprove(_toToken, bal);
        }
        // Meta pools
        else if (_toToken == ycrvBUSD || _toToken == ycrvFRAX || _toToken == ycrvALUSD || _toToken == ycrvLUSD) {
            // CRV Token = CRV Pool
            address crvToken = IYearn(_toToken).token();

            depositAmounts4[_curveOffset + 1] = _amount;
            IERC20(_fromToken).safeApprove(crvMetaZapper, 0);
            IERC20(_fromToken).safeApprove(crvMetaZapper, _amount);

            ICurveZapSimple(crvMetaZapper).add_liquidity(crvToken, depositAmounts4, 0);

            bal = IERC20(crvToken).balanceOf(address(this));
            IERC20(crvToken).safeApprove(_toToken, 0);
            IERC20(crvToken).safeApprove(_toToken, bal);
        }

        IYearn(_toToken).deposit();
    }

    function _isBare(address _token) internal pure returns (bool) {
        return (_token == DAI ||
            _token == USDC ||
            _token == USDT ||
            _token == TUSD ||
            _token == SUSD ||
            _token == BUSD ||
            _token == USDP ||
            _token == FRAX ||
            _token == ALUSD ||
            _token == LUSD ||
            _token == USDN);
    }

    function _isYearn(address _token) internal pure returns (bool) {
        return (_token == yDAI || _token == yUSDC || _token == yUSDT || _token == yTUSD || _token == ySUSD);
    }

    function _isYearnCRV(address _token) internal pure returns (bool) {
        return (_token == yCRV ||
            _token == ycrvSUSD ||
            _token == ycrvYBUSD ||
            _token == ycrvBUSD ||
            _token == ycrvUSDP ||
            _token == ycrvFRAX ||
            _token == ycrvALUSD ||
            _token == ycrvLUSD ||
            _token == ycrvUSDN ||
            _token == ycrvThree ||
            _token == ycrvIB ||
            _token == ycrvMUSD ||
            _token == ycrvUST ||
            _token == ycrvDUSD);
    }

    function _isCRV(address _token) internal pure returns (bool) {
        return (_token == crvY ||
            _token == crvSUSD ||
            _token == crvYBUSD ||
            _token == crvBUSD ||
            _token == crvUSDP ||
            _token == crvFRAX ||
            _token == crvALUSD ||
            _token == crvLUSD ||
            _token == crvThree ||
            _token == crvUSDN ||
            _token == crvDUSD ||
            _token == crvMUSD ||
            _token == crvUST ||
            _token == crvIB);
    }

    function _isCompound(address _token) internal pure returns (bool) {
        return (_token == cDAI || _token == cUSDC || _token == cUSDT || _token == cTUSD);
    }

    function _isAave(address _token) internal pure returns (bool) {
        return (_token == aDAI || _token == aUSDC || _token == aUSDT || _token == aTUSD || _token == aSUSD);
    }
}

// File: Context.sol



// SPDX-License-Identifier: MIT

pragma solidity >=0.6.0 <0.8.0;

/*
 * @dev Provides information about the current execution context, including the
 * sender of the transaction and its data. While these are generally available
 * via msg.sender and msg.data, they should not be accessed in such a direct
 * manner, since when dealing with GSN meta-transactions the account sending and
 * paying for execution may not be the actual sender (as far as an application
 * is concerned).
 *
 * This contract is only required for intermediate, library-like contracts.
 */
abstract contract Context {
    function _msgSender() internal view virtual returns (address payable) {
        return msg.sender;
    }

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

// File: ERC20.sol



// SPDX-License-Identifier: MIT

pragma solidity >=0.6.0 <0.8.0;

import "./Context.sol";
import "./IERC20.sol";
import "./SafeMath.sol";

/**
 * @dev Implementation of the {IERC20} interface.
 *
 * This implementation is agnostic to the way tokens are created. This means
 * that a supply mechanism has to be added in a derived contract using {_mint}.
 * For a generic mechanism see {ERC20PresetMinterPauser}.
 *
 * TIP: For a detailed writeup see our guide
 * https://forum.zeppelin.solutions/t/how-to-implement-erc20-supply-mechanisms/226[How
 * to implement supply mechanisms].
 *
 * We have followed general OpenZeppelin guidelines: functions revert instead
 * of returning `false` on failure. This behavior is nonetheless conventional
 * and does not conflict with the expectations of ERC20 applications.
 *
 * Additionally, an {Approval} event is emitted on calls to {transferFrom}.
 * This allows applications to reconstruct the allowance for all accounts just
 * by listening to said events. Other implementations of the EIP may not emit
 * these events, as it isn't required by the specification.
 *
 * Finally, the non-standard {decreaseAllowance} and {increaseAllowance}
 * functions have been added to mitigate the well-known issues around setting
 * allowances. See {IERC20-approve}.
 */
contract ERC20 is Context, IERC20 {
    using SafeMath for uint256;

    mapping (address => uint256) private _balances;

    mapping (address => mapping (address => uint256)) private _allowances;

    uint256 private _totalSupply;

    string private _name;
    string private _symbol;
    uint8 private _decimals;

    /**
     * @dev Sets the values for {name} and {symbol}, initializes {decimals} with
     * a default value of 18.
     *
     * To select a different value for {decimals}, use {_setupDecimals}.
     *
     * All three of these values are immutable: they can only be set once during
     * construction.
     */
    constructor (string memory name_, string memory symbol_) public {
        _name = name_;
        _symbol = symbol_;
        _decimals = 18;
    }

    /**
     * @dev Returns the name of the token.
     */
    function name() public view virtual returns (string memory) {
        return _name;
    }

    /**
     * @dev Returns the symbol of the token, usually a shorter version of the
     * name.
     */
    function symbol() public view virtual returns (string memory) {
        return _symbol;
    }

    /**
     * @dev Returns the number of decimals used to get its user representation.
     * For example, if `decimals` equals `2`, a balance of `505` tokens should
     * be displayed to a user as `5,05` (`505 / 10 ** 2`).
     *
     * Tokens usually opt for a value of 18, imitating the relationship between
     * Ether and Wei. This is the value {ERC20} uses, unless {_setupDecimals} is
     * called.
     *
     * NOTE: This information is only used for _display_ purposes: it in
     * no way affects any of the arithmetic of the contract, including
     * {IERC20-balanceOf} and {IERC20-transfer}.
     */
    function decimals() public view virtual returns (uint8) {
        return _decimals;
    }

    /**
     * @dev See {IERC20-totalSupply}.
     */
    function totalSupply() public view virtual override returns (uint256) {
        return _totalSupply;
    }

    /**
     * @dev See {IERC20-balanceOf}.
     */
    function balanceOf(address account) public view virtual override returns (uint256) {
        return _balances[account];
    }

    /**
     * @dev See {IERC20-transfer}.
     *
     * Requirements:
     *
     * - `recipient` cannot be the zero address.
     * - the caller must have a balance of at least `amount`.
     */
    function transfer(address recipient, uint256 amount) public virtual override returns (bool) {
        _transfer(_msgSender(), recipient, amount);
        return true;
    }

    /**
     * @dev See {IERC20-allowance}.
     */
    function allowance(address owner, address spender) public view virtual override returns (uint256) {
        return _allowances[owner][spender];
    }

    /**
     * @dev See {IERC20-approve}.
     *
     * Requirements:
     *
     * - `spender` cannot be the zero address.
     */
    function approve(address spender, uint256 amount) public virtual override returns (bool) {
        _approve(_msgSender(), spender, amount);
        return true;
    }

    /**
     * @dev See {IERC20-transferFrom}.
     *
     * Emits an {Approval} event indicating the updated allowance. This is not
     * required by the EIP. See the note at the beginning of {ERC20}.
     *
     * Requirements:
     *
     * - `sender` and `recipient` cannot be the zero address.
     * - `sender` must have a balance of at least `amount`.
     * - the caller must have allowance for ``sender``'s tokens of at least
     * `amount`.
     */
    function transferFrom(address sender, address recipient, uint256 amount) public virtual override returns (bool) {
        _transfer(sender, recipient, amount);
        _approve(sender, _msgSender(), _allowances[sender][_msgSender()].sub(amount, "ERC20: transfer amount exceeds allowance"));
        return true;
    }

    /**
     * @dev Atomically increases the allowance granted to `spender` by the caller.
     *
     * This is an alternative to {approve} that can be used as a mitigation for
     * problems described in {IERC20-approve}.
     *
     * Emits an {Approval} event indicating the updated allowance.
     *
     * Requirements:
     *
     * - `spender` cannot be the zero address.
     */
    function increaseAllowance(address spender, uint256 addedValue) public virtual returns (bool) {
        _approve(_msgSender(), spender, _allowances[_msgSender()][spender].add(addedValue));
        return true;
    }

    /**
     * @dev Atomically decreases the allowance granted to `spender` by the caller.
     *
     * This is an alternative to {approve} that can be used as a mitigation for
     * problems described in {IERC20-approve}.
     *
     * Emits an {Approval} event indicating the updated allowance.
     *
     * Requirements:
     *
     * - `spender` cannot be the zero address.
     * - `spender` must have allowance for the caller of at least
     * `subtractedValue`.
     */
    function decreaseAllowance(address spender, uint256 subtractedValue) public virtual returns (bool) {
        _approve(_msgSender(), spender, _allowances[_msgSender()][spender].sub(subtractedValue, "ERC20: decreased allowance below zero"));
        return true;
    }

    /**
     * @dev Moves tokens `amount` from `sender` to `recipient`.
     *
     * This is internal function is equivalent to {transfer}, and can be used to
     * e.g. implement automatic token fees, slashing mechanisms, etc.
     *
     * Emits a {Transfer} event.
     *
     * Requirements:
     *
     * - `sender` cannot be the zero address.
     * - `recipient` cannot be the zero address.
     * - `sender` must have a balance of at least `amount`.
     */
    function _transfer(address sender, address recipient, uint256 amount) internal virtual {
        require(sender != address(0), "ERC20: transfer from the zero address");
        require(recipient != address(0), "ERC20: transfer to the zero address");

        _beforeTokenTransfer(sender, recipient, amount);

        _balances[sender] = _balances[sender].sub(amount, "ERC20: transfer amount exceeds balance");
        _balances[recipient] = _balances[recipient].add(amount);
        emit Transfer(sender, recipient, amount);
    }

    /** @dev Creates `amount` tokens and assigns them to `account`, increasing
     * the total supply.
     *
     * Emits a {Transfer} event with `from` set to the zero address.
     *
     * Requirements:
     *
     * - `to` cannot be the zero address.
     */
    function _mint(address account, uint256 amount) internal virtual {
        require(account != address(0), "ERC20: mint to the zero address");

        _beforeTokenTransfer(address(0), account, amount);

        _totalSupply = _totalSupply.add(amount);
        _balances[account] = _balances[account].add(amount);
        emit Transfer(address(0), account, amount);
    }

    /**
     * @dev Destroys `amount` tokens from `account`, reducing the
     * total supply.
     *
     * Emits a {Transfer} event with `to` set to the zero address.
     *
     * Requirements:
     *
     * - `account` cannot be the zero address.
     * - `account` must have at least `amount` tokens.
     */
    function _burn(address account, uint256 amount) internal virtual {
        require(account != address(0), "ERC20: burn from the zero address");

        _beforeTokenTransfer(account, address(0), amount);

        _balances[account] = _balances[account].sub(amount, "ERC20: burn amount exceeds balance");
        _totalSupply = _totalSupply.sub(amount);
        emit Transfer(account, address(0), amount);
    }

    /**
     * @dev Sets `amount` as the allowance of `spender` over the `owner` s tokens.
     *
     * This internal function is equivalent to `approve`, and can be used to
     * e.g. set automatic allowances for certain subsystems, etc.
     *
     * Emits an {Approval} event.
     *
     * Requirements:
     *
     * - `owner` cannot be the zero address.
     * - `spender` cannot be the zero address.
     */
    function _approve(address owner, address spender, uint256 amount) internal virtual {
        require(owner != address(0), "ERC20: approve from the zero address");
        require(spender != address(0), "ERC20: approve to the zero address");

        _allowances[owner][spender] = amount;
        emit Approval(owner, spender, amount);
    }

    /**
     * @dev Sets {decimals} to a value other than the default one of 18.
     *
     * WARNING: This function should only be called from the constructor. Most
     * applications that interact with token contracts will not expect
     * {decimals} to ever change, and may work incorrectly if it does.
     */
    function _setupDecimals(uint8 decimals_) internal virtual {
        _decimals = decimals_;
    }

    /**
     * @dev Hook that is called before any transfer of tokens. This includes
     * minting and burning.
     *
     * Calling conditions:
     *
     * - when `from` and `to` are both non-zero, `amount` of ``from``'s tokens
     * will be to transferred to `to`.
     * - when `from` is zero, `amount` tokens will be minted for `to`.
     * - when `to` is zero, `amount` of ``from``'s tokens will be burned.
     * - `from` and `to` are never both zero.
     *
     * To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].
     */
    function _beforeTokenTransfer(address from, address to, uint256 amount) internal virtual { }
}

// File: IATokenV2.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.7.3;

interface IATokenV2 {
    function ATOKEN_REVISION() external view returns (uint256);

    function DOMAIN_SEPARATOR() external view returns (bytes32);

    function EIP712_REVISION() external view returns (bytes memory);

    function PERMIT_TYPEHASH() external view returns (bytes32);

    function POOL() external view returns (address);

    function RESERVE_TREASURY_ADDRESS() external view returns (address);

    function UINT_MAX_VALUE() external view returns (uint256);

    function UNDERLYING_ASSET_ADDRESS() external view returns (address);

    function _nonces(address) external view returns (uint256);

    function allowance(address owner, address spender) external view returns (uint256);

    function approve(address spender, uint256 amount) external returns (bool);

    function balanceOf(address user) external view returns (uint256);

    function burn(
        address user,
        address receiverOfUnderlying,
        uint256 amount,
        uint256 index
    ) external;

    function decimals() external view returns (uint8);

    function decreaseAllowance(address spender, uint256 subtractedValue) external returns (bool);

    function getScaledUserBalanceAndSupply(address user) external view returns (uint256, uint256);

    function increaseAllowance(address spender, uint256 addedValue) external returns (bool);

    function initialize(
        uint8 underlyingAssetDecimals,
        string memory tokenName,
        string memory tokenSymbol
    ) external;

    function mint(
        address user,
        uint256 amount,
        uint256 index
    ) external returns (bool);

    function mintToTreasury(uint256 amount, uint256 index) external;

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

    function permit(
        address owner,
        address spender,
        uint256 value,
        uint256 deadline,
        uint8 v,
        bytes32 r,
        bytes32 s
    ) external;

    function scaledBalanceOf(address user) external view returns (uint256);

    function scaledTotalSupply() external view returns (uint256);

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

    function totalSupply() external view returns (uint256);

    function transfer(address recipient, uint256 amount) external returns (bool);

    function transferFrom(
        address sender,
        address recipient,
        uint256 amount
    ) external returns (bool);

    function transferOnLiquidation(
        address from,
        address to,
        uint256 value
    ) external;

    function transferUnderlyingTo(address target, uint256 amount) external returns (uint256);
}

// File: IBasket.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.7.3;

interface IBasket {
    function transfer(address dst, uint256 amount) external returns (bool);

    function totalSupply() external view returns (uint256);

    function mint(uint256) external;

    function getOne() external view returns (address[] memory, uint256[] memory);

    function getAssetsAndBalances() external view returns (address[] memory, uint256[] memory);

    function burn(uint256) external;

    function viewMint(uint256 _amountOut) external view returns (uint256[] memory _amountsIn);
}

// File: ICToken.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.7.3;

interface ICToken {
    function _acceptAdmin() external returns (uint256);

    function _addReserves(uint256 addAmount) external returns (uint256);

    function _reduceReserves(uint256 reduceAmount) external returns (uint256);

    function _setComptroller(address newComptroller) external returns (uint256);

    function _setImplementation(
        address implementation_,
        bool allowResign,
        bytes memory becomeImplementationData
    ) external;

    function _setInterestRateModel(address newInterestRateModel) external returns (uint256);

    function _setPendingAdmin(address newPendingAdmin) external returns (uint256);

    function _setReserveFactor(uint256 newReserveFactorMantissa) external returns (uint256);

    function accrualBlockNumber() external view returns (uint256);

    function accrueInterest() external returns (uint256);

    function admin() external view returns (address);

    function allowance(address owner, address spender) external view returns (uint256);

    function approve(address spender, uint256 amount) external returns (bool);

    function balanceOf(address owner) external view returns (uint256);

    function balanceOfUnderlying(address owner) external returns (uint256);

    function borrow(uint256 borrowAmount) external returns (uint256);

    function borrowBalanceCurrent(address account) external returns (uint256);

    function borrowBalanceStored(address account) external view returns (uint256);

    function borrowIndex() external view returns (uint256);

    function borrowRatePerBlock() external view returns (uint256);

    function comptroller() external view returns (address);

    function decimals() external view returns (uint8);

    function delegateToImplementation(bytes memory data) external returns (bytes memory);

    function delegateToViewImplementation(bytes memory data) external view returns (bytes memory);

    function exchangeRateCurrent() external returns (uint256);

    function exchangeRateStored() external view returns (uint256);

    function getAccountSnapshot(address account)
        external
        view
        returns (
            uint256,
            uint256,
            uint256,
            uint256
        );

    function getCash() external view returns (uint256);

    function implementation() external view returns (address);

    function interestRateModel() external view returns (address);

    function isCToken() external view returns (bool);

    function liquidateBorrow(
        address borrower,
        uint256 repayAmount,
        address cTokenCollateral
    ) external returns (uint256);

    function mint(uint256 mintAmount) external returns (uint256);

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

    function pendingAdmin() external view returns (address);

    function redeem(uint256 redeemTokens) external returns (uint256);

    function redeemUnderlying(uint256 redeemAmount) external returns (uint256);

    function repayBorrow(uint256 repayAmount) external returns (uint256);

    function repayBorrowBehalf(address borrower, uint256 repayAmount) external returns (uint256);

    function reserveFactorMantissa() external view returns (uint256);

    function seize(
        address liquidator,
        address borrower,
        uint256 seizeTokens
    ) external returns (uint256);

    function supplyRatePerBlock() external view returns (uint256);

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

    function totalBorrows() external view returns (uint256);

    function totalBorrowsCurrent() external returns (uint256);

    function totalReserves() external view returns (uint256);

    function totalSupply() external view returns (uint256);

    function transfer(address dst, uint256 amount) external returns (bool);

    function transferFrom(
        address src,
        address dst,
        uint256 amount
    ) external returns (bool);

    function underlying() external view returns (address);
}

// File: ICurve.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.7.3;

interface ICurvePool {
    function exchange(
        int128 i,
        int128 j,
        uint256 _dx,
        uint256 _min_dy
    ) external;

    function get_dy(
        int128 i,
        int128 j,
        uint256 _dx
    ) external view returns (uint256);

    function get_virtual_price() external view returns (uint256);
}

interface ICurveLINK {
    function A() external view returns (uint256);

    function A_precise() external view returns (uint256);

    function get_virtual_price() external view returns (uint256);

    function calc_token_amount(uint256[2] memory _amounts, bool _is_deposit) external view returns (uint256);

    function add_liquidity(uint256[2] memory _amounts, uint256 _min_mint_amount) external returns (uint256);

    function get_dy(
        int128 i,
        int128 j,
        uint256 _dx
    ) external view returns (uint256);

    function exchange(
        int128 i,
        int128 j,
        uint256 _dx,
        uint256 _min_dy
    ) external returns (uint256);

    function remove_liquidity(uint256 _amount, uint256[2] memory _min_amounts) external returns (uint256[2] memory);

    function remove_liquidity_imbalance(uint256[2] memory _amounts, uint256 _max_burn_amount)
        external
        returns (uint256);

    function calc_withdraw_one_coin(uint256 _token_amount, int128 i) external view returns (uint256);

    function remove_liquidity_one_coin(
        uint256 _token_amount,
        int128 i,
        uint256 _min_amount
    ) external returns (uint256);

    function ramp_A(uint256 _future_A, uint256 _future_time) external;

    function stop_ramp_A() external;

    function commit_new_fee(uint256 _new_fee, uint256 _new_admin_fee) external;

    function apply_new_fee() external;

    function revert_new_parameters() external;

    function commit_transfer_ownership(address _owner) external;

    function apply_transfer_ownership() external;

    function revert_transfer_ownership() external;

    function admin_balances(uint256 i) external view returns (uint256);

    function withdraw_admin_fees() external;

    function donate_admin_fees() external;

    function kill_me() external;

    function unkill_me() external;

    function coins(uint256 arg0) external view returns (address);

    function balances(uint256 arg0) external view returns (uint256);

    function fee() external view returns (uint256);

    function admin_fee() external view returns (uint256);

    function previous_balances(uint256 arg0) external view returns (uint256);

    function block_timestamp_last() external view returns (uint256);

    function owner() external view returns (address);

    function lp_token() external view returns (address);

    function initial_A() external view returns (uint256);

    function future_A() external view returns (uint256);

    function initial_A_time() external view returns (uint256);

    function future_A_time() external view returns (uint256);

    function admin_actions_deadline() external view returns (uint256);

    function transfer_ownership_deadline() external view returns (uint256);

    function future_fee() external view returns (uint256);

    function future_admin_fee() external view returns (uint256);

    function future_owner() external view returns (address);
}

interface ILinkGauge {
    function decimals() external view returns (uint256);

    function integrate_checkpoint() external view returns (uint256);

    function user_checkpoint(address addr) external returns (bool);

    function claimable_tokens(address addr) external returns (uint256);

    function claimable_reward(address _addr, address _token) external returns (uint256);

    function claim_rewards() external;

    function claim_rewards(address _addr) external;

    function claim_historic_rewards(address[8] memory _reward_tokens) external;

    function claim_historic_rewards(address[8] memory _reward_tokens, address _addr) external;

    function kick(address addr) external;

    function set_approve_deposit(address addr, bool can_deposit) external;

    function deposit(uint256 _value) external;

    function deposit(uint256 _value, address _addr) external;

    function withdraw(uint256 _value) external;

    function allowance(address _owner, address _spender) external view returns (uint256);

    function transfer(address _to, uint256 _value) external returns (bool);

    function transferFrom(
        address _from,
        address _to,
        uint256 _value
    ) external returns (bool);

    function approve(address _spender, uint256 _value) external returns (bool);

    function increaseAllowance(address _spender, uint256 _added_value) external returns (bool);

    function decreaseAllowance(address _spender, uint256 _subtracted_value) external returns (bool);

    function set_rewards(
        address _reward_contract,
        bytes32 _sigs,
        address[8] memory _reward_tokens
    ) external;

    function set_killed(bool _is_killed) external;

    function commit_transfer_ownership(address addr) external;

    function accept_transfer_ownership() external;

    function minter() external view returns (address);

    function crv_token() external view returns (address);

    function lp_token() external view returns (address);

    function controller() external view returns (address);

    function voting_escrow() external view returns (address);

    function future_epoch_time() external view returns (uint256);

    function balanceOf(address arg0) external view returns (uint256);

    function totalSupply() external view returns (uint256);

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

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

    function approved_to_deposit(address arg0, address arg1) external view returns (bool);

    function working_balances(address arg0) external view returns (uint256);

    function working_supply() external view returns (uint256);

    function period() external view returns (int128);

    function period_timestamp(uint256 arg0) external view returns (uint256);

    function integrate_inv_supply(uint256 arg0) external view returns (uint256);

    function integrate_inv_supply_of(address arg0) external view returns (uint256);

    function integrate_checkpoint_of(address arg0) external view returns (uint256);

    function integrate_fraction(address arg0) external view returns (uint256);

    function inflation_rate() external view returns (uint256);

    function reward_contract() external view returns (address);

    function reward_tokens(uint256 arg0) external view returns (address);

    function reward_integral(address arg0) external view returns (uint256);

    function reward_integral_for(address arg0, address arg1) external view returns (uint256);

    function admin() external view returns (address);

    function future_admin() external view returns (address);

    function is_killed() external view returns (bool);
}

// File: ICurveZap.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.7.3;

interface ICurveZapSimple {
    function add_liquidity(uint256[3] memory _deposit_amounts, uint256 _min_mint_amount) external;

    function add_liquidity(
        uint256[3] memory _deposit_amounts,
        uint256 _min_mint_amount,
        bool use_underlying
    ) external;

    function add_liquidity(uint256[4] memory _deposit_amounts, uint256 _min_mint_amount) external;

    function add_liquidity(
        address _pool,
        uint256[4] memory _deposit_amounts,
        uint256 _min_mint_amount
    ) external returns (uint256);

    function add_liquidity(
        address _pool,
        uint256[4] memory _deposit_amounts,
        uint256 _min_mint_amount,
        address _receiver
    ) external returns (uint256);

    function remove_liquidity_one_coin(
        uint256 _token_amount,
        int128 i,
        uint256 min_amount,
        bool _donate_dust
    ) external;

    function remove_liquidity_one_coin(
        uint256 _token_amount,
        int128 i,
        uint256 min_amount
    ) external;

    function remove_liquidity_one_coin(
        address pool,
        uint256 _token_amount,
        int128 i,
        uint256 min_amount,
        address _receiver
    ) external returns (uint256);

    function remove_liquidity_one_coin(
        uint256 _token_amount,
        int128 i,
        uint256 min_amount,
        address _receiver
    ) external returns (uint256);

    function calc_withdraw_one_coin(uint256 _token_amount, int128 i) external view returns (uint256);

    function calc_withdraw_one_coin(
        uint256 _token_amount,
        int128 i,
        bool use_underlying
    ) external view returns (uint256);

    function calc_withdraw_one_coin(
        address pool,
        uint256 _token_amount,
        int128 i
    ) external view returns (uint256);
}

// File: IERC20.sol



// SPDX-License-Identifier: MIT

pragma solidity >=0.6.0 <0.8.0;

/**
 * @dev Interface of the ERC20 standard as defined in the EIP.
 */
interface IERC20 {
    /**
     * @dev Returns the amount of tokens in existence.
     */
    function totalSupply() external view returns (uint256);

    /**
     * @dev Returns the amount of tokens owned by `account`.
     */
    function balanceOf(address account) external view returns (uint256);

    /**
     * @dev Moves `amount` tokens from the caller's account to `recipient`.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transfer(address recipient, uint256 amount) external returns (bool);

    /**
     * @dev Returns the remaining number of tokens that `spender` will be
     * allowed to spend on behalf of `owner` through {transferFrom}. This is
     * zero by default.
     *
     * This value changes when {approve} or {transferFrom} are called.
     */
    function allowance(address owner, address spender) external view returns (uint256);

    /**
     * @dev Sets `amount` as the allowance of `spender` over the caller's tokens.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * IMPORTANT: Beware that changing an allowance with this method brings the risk
     * that someone may use both the old and the new allowance by unfortunate
     * transaction ordering. One possible solution to mitigate this race
     * condition is to first reduce the spender's allowance to 0 and set the
     * desired value afterwards:
     * https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
     *
     * Emits an {Approval} event.
     */
    function approve(address spender, uint256 amount) external returns (bool);

    /**
     * @dev Moves `amount` tokens from `sender` to `recipient` using the
     * allowance mechanism. `amount` is then deducted from the caller's
     * allowance.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transferFrom(address sender, address recipient, uint256 amount) external returns (bool);

    /**
     * @dev Emitted when `value` tokens are moved from one account (`from`) to
     * another (`to`).
     *
     * Note that `value` may be zero.
     */
    event Transfer(address indexed from, address indexed to, uint256 value);

    /**
     * @dev Emitted when the allowance of a `spender` for an `owner` is set by
     * a call to {approve}. `value` is the new allowance.
     */
    event Approval(address indexed owner, address indexed spender, uint256 value);
}

// File: ILendingPoolV2.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.7.3;

interface ILendingPoolV2 {
    function FLASHLOAN_PREMIUM_TOTAL() external view returns (uint256);

    function LENDINGPOOL_REVISION() external view returns (uint256);

    function MAX_NUMBER_RESERVES() external view returns (uint256);

    function MAX_STABLE_RATE_BORROW_SIZE_PERCENT() external view returns (uint256);

    function borrow(
        address asset,
        uint256 amount,
        uint256 interestRateMode,
        uint16 referralCode,
        address onBehalfOf
    ) external;

    function deposit(
        address asset,
        uint256 amount,
        address onBehalfOf,
        uint16 referralCode
    ) external;

    function finalizeTransfer(
        address asset,
        address from,
        address to,
        uint256 amount,
        uint256 balanceFromBefore,
        uint256 balanceToBefore
    ) external;

    function flashLoan(
        address receiverAddress,
        address[] memory assets,
        uint256[] memory amounts,
        uint256[] memory modes,
        address onBehalfOf,
        bytes memory params,
        uint16 referralCode
    ) external;

    function getAddressesProvider() external view returns (address);

    function getConfiguration(address asset) external view returns (uint256);

    function getReserveData(address asset)
        external
        view
        returns (
            uint256,
            uint128,
            uint128,
            uint128,
            uint128,
            uint128,
            uint40,
            address,
            address,
            address,
            address,
            uint8
        );

    function getReserveNormalizedIncome(address asset) external view returns (uint256);

    function getReserveNormalizedVariableDebt(address asset) external view returns (uint256);

    function getReservesList() external view returns (address[] memory);

    function getUserAccountData(address user)
        external
        view
        returns (
            uint256 totalCollateralETH,
            uint256 totalDebtETH,
            uint256 availableBorrowsETH,
            uint256 currentLiquidationThreshold,
            uint256 ltv,
            uint256 healthFactor
        );

    function initReserve(
        address asset,
        address aTokenAddress,
        address stableDebtAddress,
        address variableDebtAddress,
        address interestRateStrategyAddress
    ) external;

    function initialize(address provider) external;

    function liquidationCall(
        address collateralAsset,
        address debtAsset,
        address user,
        uint256 debtToCover,
        bool receiveAToken
    ) external;

    function paused() external view returns (bool);

    function rebalanceStableBorrowRate(address asset, address user) external;

    function repay(
        address asset,
        uint256 amount,
        uint256 rateMode,
        address onBehalfOf
    ) external returns (uint256);

    function setConfiguration(address asset, uint256 configuration) external;

    function setPause(bool val) external;

    function setReserveInterestRateStrategyAddress(address asset, address rateStrategyAddress) external;

    function setUserUseReserveAsCollateral(address asset, bool useAsCollateral) external;

    function swapBorrowRateMode(address asset, uint256 rateMode) external;

    function withdraw(
        address asset,
        uint256 amount,
        address to
    ) external returns (uint256);
}

// File: IYearn.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.7.3;

interface IYearn {
    function initialize(
        address token,
        address governance,
        address rewards,
        string memory nameOverride,
        string memory symbolOverride
    ) external;

    function initialize(
        address token,
        address governance,
        address rewards,
        string memory nameOverride,
        string memory symbolOverride,
        address guardian
    ) external;

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

    function setName(string memory name) external;

    function setSymbol(string memory symbol) external;

    function setGovernance(address governance) external;

    function acceptGovernance() external;

    function setManagement(address management) external;

    function setGuestList(address guestList) external;

    function setRewards(address rewards) external;

    function setLockedProfitDegration(uint256 degration) external;

    function setDepositLimit(uint256 limit) external;

    function setPerformanceFee(uint256 fee) external;

    function setManagementFee(uint256 fee) external;

    function setGuardian(address guardian) external;

    function setEmergencyShutdown(bool active) external;

    function setWithdrawalQueue(address[20] memory queue) external;

    function transfer(address receiver, uint256 amount) external returns (bool);

    function transferFrom(
        address sender,
        address receiver,
        uint256 amount
    ) external returns (bool);

    function approve(address spender, uint256 amount) external returns (bool);

    function increaseAllowance(address spender, uint256 amount) external returns (bool);

    function decreaseAllowance(address spender, uint256 amount) external returns (bool);

    function permit(
        address owner,
        address spender,
        uint256 amount,
        uint256 expiry,
        bytes memory signature
    ) external returns (bool);

    function totalAssets() external view returns (uint256);

    function deposit() external returns (uint256);

    function deposit(uint256 _amount) external returns (uint256);

    function deposit(uint256 _amount, address recipient) external returns (uint256);

    function maxAvailableShares() external view returns (uint256);

    function withdraw() external returns (uint256);

    function withdraw(uint256 maxShares) external returns (uint256);

    function withdraw(uint256 maxShares, address recipient) external returns (uint256);

    function withdraw(
        uint256 maxShares,
        address recipient,
        uint256 maxLoss
    ) external returns (uint256);

    function pricePerShare() external view returns (uint256);

    function addStrategy(
        address strategy,
        uint256 debtRatio,
        uint256 minDebtPerHarvest,
        uint256 maxDebtPerHarvest,
        uint256 performanceFee
    ) external;

    function updateStrategyDebtRatio(address strategy, uint256 debtRatio) external;

    function updateStrategyMinDebtPerHarvest(address strategy, uint256 minDebtPerHarvest) external;

    function updateStrategyMaxDebtPerHarvest(address strategy, uint256 maxDebtPerHarvest) external;

    function updateStrategyPerformanceFee(address strategy, uint256 performanceFee) external;

    function migrateStrategy(address oldVersion, address newVersion) external;

    function revokeStrategy() external;

    function revokeStrategy(address strategy) external;

    function addStrategyToQueue(address strategy) external;

    function removeStrategyFromQueue(address strategy) external;

    function debtOutstanding() external view returns (uint256);

    function debtOutstanding(address strategy) external view returns (uint256);

    function creditAvailable() external view returns (uint256);

    function creditAvailable(address strategy) external view returns (uint256);

    function availableDepositLimit() external view returns (uint256);

    function expectedReturn() external view returns (uint256);

    function expectedReturn(address strategy) external view returns (uint256);

    function report(
        uint256 gain,
        uint256 loss,
        uint256 _debtPayment
    ) external returns (uint256);

    function sweep(address token) external;

    function sweep(address token, uint256 amount) external;

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

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

    function decimals() external view returns (uint256);

    function precisionFactor() external view returns (uint256);

    function balanceOf(address arg0) external view returns (uint256);

    function allowance(address arg0, address arg1) external view returns (uint256);

    function totalSupply() external view returns (uint256);

    function token() external view returns (address);

    function governance() external view returns (address);

    function management() external view returns (address);

    function guardian() external view returns (address);

    function guestList() external view returns (address);

    function strategies(address arg0)
        external
        view
        returns (
            uint256 performanceFee,
            uint256 activation,
            uint256 debtRatio,
            uint256 minDebtPerHarvest,
            uint256 maxDebtPerHarvest,
            uint256 lastReport,
            uint256 totalDebt,
            uint256 totalGain,
            uint256 totalLoss
        );

    function withdrawalQueue(uint256 arg0) external view returns (address);

    function emergencyShutdown() external view returns (bool);

    function depositLimit() external view returns (uint256);

    function debtRatio() external view returns (uint256);

    function totalDebt() external view returns (uint256);

    function lastReport() external view returns (uint256);

    function activation() external view returns (uint256);

    function lockedProfit() external view returns (uint256);

    function lockedProfitDegration() external view returns (uint256);

    function rewards() external view returns (address);

    function managementFee() external view returns (uint256);

    function performanceFee() external view returns (uint256);

    function nonces(address arg0) external view returns (uint256);

    function DOMAIN_SEPARATOR() external view returns (bytes32);
}

// File: Ownable.sol



// SPDX-License-Identifier: MIT

pragma solidity >=0.6.0 <0.8.0;

import "./Context.sol";
/**
 * @dev Contract module which provides a basic access control mechanism, where
 * there is an account (an owner) that can be granted exclusive access to
 * specific functions.
 *
 * By default, the owner account will be the one that deploys the contract. This
 * can later be changed with {transferOwnership}.
 *
 * This module is used through inheritance. It will make available the modifier
 * `onlyOwner`, which can be applied to your functions to restrict their use to
 * the owner.
 */
abstract 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 virtual returns (address) {
        return _owner;
    }

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

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

    /**
     * @dev Transfers ownership of the contract to a new account (`newOwner`).
     * Can only be called by the current owner.
     */
    function transferOwnership(address newOwner) public virtual onlyOwner {
        require(newOwner != address(0), "Ownable: new owner is the zero address");
        emit OwnershipTransferred(_owner, newOwner);
        _owner = newOwner;
    }
}

// File: SafeERC20.sol



// SPDX-License-Identifier: MIT

pragma solidity >=0.6.0 <0.8.0;

import "./IERC20.sol";
import "./SafeMath.sol";
import "./Address.sol";

/**
 * @title SafeERC20
 * @dev Wrappers around ERC20 operations that throw on failure (when the token
 * contract returns false). Tokens that return no value (and instead revert or
 * throw on failure) are also supported, non-reverting calls are assumed to be
 * successful.
 * To use this library you can add a `using SafeERC20 for IERC20;` statement to your contract,
 * which allows you to call the safe operations as `token.safeTransfer(...)`, etc.
 */
library SafeERC20 {
    using SafeMath for uint256;
    using Address for address;

    function safeTransfer(IERC20 token, address to, uint256 value) internal {
        _callOptionalReturn(token, abi.encodeWithSelector(token.transfer.selector, to, value));
    }

    function safeTransferFrom(IERC20 token, address from, address to, uint256 value) internal {
        _callOptionalReturn(token, abi.encodeWithSelector(token.transferFrom.selector, from, to, value));
    }

    /**
     * @dev Deprecated. This function has issues similar to the ones found in
     * {IERC20-approve}, and its usage is discouraged.
     *
     * Whenever possible, use {safeIncreaseAllowance} and
     * {safeDecreaseAllowance} instead.
     */
    function safeApprove(IERC20 token, address spender, uint256 value) internal {
        // safeApprove should only be called when setting an initial allowance,
        // or when resetting it to zero. To increase and decrease it, use
        // 'safeIncreaseAllowance' and 'safeDecreaseAllowance'
        // solhint-disable-next-line max-line-length
        require((value == 0) || (token.allowance(address(this), spender) == 0),
            "SafeERC20: approve from non-zero to non-zero allowance"
        );
        _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, value));
    }

    function safeIncreaseAllowance(IERC20 token, address spender, uint256 value) internal {
        uint256 newAllowance = token.allowance(address(this), spender).add(value);
        _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
    }

    function safeDecreaseAllowance(IERC20 token, address spender, uint256 value) internal {
        uint256 newAllowance = token.allowance(address(this), spender).sub(value, "SafeERC20: decreased allowance below zero");
        _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
    }

    /**
     * @dev Imitates a Solidity high-level call (i.e. a regular function call to a contract), relaxing the requirement
     * on the return value: the return value is optional (but if data is returned, it must not be false).
     * @param token The token targeted by the call.
     * @param data The call data (encoded using abi.encode or one of its variants).
     */
    function _callOptionalReturn(IERC20 token, bytes memory data) private {
        // We need to perform a low level call here, to bypass Solidity's return data size checking mechanism, since
        // we're implementing it ourselves. We use {Address.functionCall} to perform this call, which verifies that
        // the target address contains contract code and also asserts for success in the low-level call.

        bytes memory returndata = address(token).functionCall(data, "SafeERC20: low-level call failed");
        if (returndata.length > 0) { // Return data is optional
            // solhint-disable-next-line max-line-length
            require(abi.decode(returndata, (bool)), "SafeERC20: ERC20 operation did not succeed");
        }
    }
}

// File: SafeMath.sol



// SPDX-License-Identifier: MIT

pragma solidity >=0.6.0 <0.8.0;

/**
 * @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, with an overflow flag.
     *
     * _Available since v3.4._
     */
    function tryAdd(uint256 a, uint256 b) internal pure returns (bool, uint256) {
        uint256 c = a + b;
        if (c < a) return (false, 0);
        return (true, c);
    }

    /**
     * @dev Returns the substraction of two unsigned integers, with an overflow flag.
     *
     * _Available since v3.4._
     */
    function trySub(uint256 a, uint256 b) internal pure returns (bool, uint256) {
        if (b > a) return (false, 0);
        return (true, a - b);
    }

    /**
     * @dev Returns the multiplication of two unsigned integers, with an overflow flag.
     *
     * _Available since v3.4._
     */
    function tryMul(uint256 a, uint256 b) internal pure returns (bool, 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 (true, 0);
        uint256 c = a * b;
        if (c / a != b) return (false, 0);
        return (true, c);
    }

    /**
     * @dev Returns the division of two unsigned integers, with a division by zero flag.
     *
     * _Available since v3.4._
     */
    function tryDiv(uint256 a, uint256 b) internal pure returns (bool, uint256) {
        if (b == 0) return (false, 0);
        return (true, a / b);
    }

    /**
     * @dev Returns the remainder of dividing two unsigned integers, with a division by zero flag.
     *
     * _Available since v3.4._
     */
    function tryMod(uint256 a, uint256 b) internal pure returns (bool, uint256) {
        if (b == 0) return (false, 0);
        return (true, a % b);
    }

    /**
     * @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) {
        require(b <= a, "SafeMath: subtraction overflow");
        return a - b;
    }

    /**
     * @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) {
        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, reverting 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) {
        require(b > 0, "SafeMath: division by zero");
        return a / b;
    }

    /**
     * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
     * reverting 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) {
        require(b > 0, "SafeMath: modulo by zero");
        return a % b;
    }

    /**
     * @dev Returns the subtraction of two unsigned integers, reverting with custom message on
     * overflow (when the result is negative).
     *
     * CAUTION: This function is deprecated because it requires allocating memory for the error
     * message unnecessarily. For custom revert reasons use {trySub}.
     *
     * Counterpart to Solidity's `-` operator.
     *
     * Requirements:
     *
     * - Subtraction cannot overflow.
     */
    function sub(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        require(b <= a, errorMessage);
        return a - b;
    }

    /**
     * @dev Returns the integer division of two unsigned integers, reverting with custom message on
     * division by zero. The result is rounded towards zero.
     *
     * CAUTION: This function is deprecated because it requires allocating memory for the error
     * message unnecessarily. For custom revert reasons use {tryDiv}.
     *
     * Counterpart to Solidity's `/` operator. Note: this function uses a
     * `revert` opcode (which leaves remaining gas untouched) while Solidity
     * uses an invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     *
     * - The divisor cannot be zero.
     */
    function div(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        require(b > 0, errorMessage);
        return a / b;
    }

    /**
     * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
     * reverting with custom message when dividing by zero.
     *
     * CAUTION: This function is deprecated because it requires allocating memory for the error
     * message unnecessarily. For custom revert reasons use {tryMod}.
     *
     * Counterpart to Solidity's `%` operator. This function uses a `revert`
     * opcode (which leaves remaining gas untouched) while Solidity uses an
     * invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     *
     * - The divisor cannot be zero.
     */
    function mod(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        require(b > 0, errorMessage);
        return a % b;
    }
}