ens-usernames/contracts/common/SafeMath.sol

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2018-04-23 05:04:49 +00:00
pragma solidity ^0.4.23;
2018-04-23 04:58:58 +00:00
/**
* Math operations with safety checks
*/
library SafeMath {
function mul(uint a, uint b) internal pure returns (uint) {
uint c = a * b;
assert(a == 0 || c / a == b);
return c;
}
function div(uint a, uint b) internal pure returns (uint) {
// assert(b > 0); // Solidity automatically throws when dividing by 0
uint c = a / b;
// assert(a == b * c + a % b); // There is no case in which this doesn't hold
return c;
}
function sub(uint a, uint b) internal pure returns (uint) {
assert(b <= a);
return a - b;
}
function add(uint a, uint b) internal pure returns (uint) {
uint c = a + b;
assert(c >= a);
return c;
}
function max64(uint64 a, uint64 b) internal pure returns (uint64) {
return a >= b ? a : b;
}
function min64(uint64 a, uint64 b) internal pure returns (uint64) {
return a < b ? a : b;
}
function max256(uint256 a, uint256 b) internal pure returns (uint256) {
return a >= b ? a : b;
}
function min256(uint256 a, uint256 b) internal pure returns (uint256) {
return a < b ? a : b;
}
}