pragma solidity ^0.7.0;

import { SafeMath } from "@openzeppelin/contracts/math/SafeMath.sol";

contract DSMath {
  uint constant WAD = 10 ** 18;
  uint constant RAY = 10 ** 27;

  function add(uint x, uint y) internal pure returns (uint z) {
    z = SafeMath.add(x, y);
  }

  function sub(uint x, uint y) internal virtual pure returns (uint z) {
    z = SafeMath.sub(x, y);
  }

  function mul(uint x, uint y) internal pure returns (uint z) {
    z = SafeMath.mul(x, y);
  }

  function div(uint x, uint y) internal pure returns (uint z) {
    z = SafeMath.div(x, y);
  }

  function wmul(uint x, uint y) internal pure returns (uint z) {
    z = SafeMath.add(SafeMath.mul(x, y), WAD / 2) / WAD;
  }

  function wdiv(uint x, uint y) internal pure returns (uint z) {
    z = SafeMath.add(SafeMath.mul(x, WAD), y / 2) / y;
  }

  function rdiv(uint x, uint y) internal pure returns (uint z) {
    z = SafeMath.add(SafeMath.mul(x, RAY), y / 2) / y;
  }

  function rmul(uint x, uint y) internal pure returns (uint z) {
    z = SafeMath.add(SafeMath.mul(x, y), RAY / 2) / RAY;
  }

  function toInt(uint x) internal pure returns (int y) {
    y = int(x);
    require(y >= 0, "int-overflow");
  }

  function toRad(uint wad) internal pure returns (uint rad) {
    rad = mul(wad, 10 ** 27);
  }

}