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SafeMath.sol
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SafeMath.sol
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pragma solidity >=0.5.0 <0.6.0;
/**
* @title SafeMath
* @dev Math operations with safety checks that throw on error
*/
library SafeMath {
/**
* @dev Multiplies two numbers, throws on overflow.
*/
function mul(uint256 a, uint256 b) internal pure returns (uint256) {
if (a == 0) {
return 0;
}
uint256 c = a * b;
assert(c / a == b);
return c;
}
/**
* @dev Integer division of two numbers, truncating the quotient.
*/
function div(uint256 a, uint256 b) internal pure returns (uint256) {
// assert(b > 0); // Solidity automatically throws when dividing by 0
uint256 c = a / b;
// assert(a == b * c + a % b); // There is no case in which this doesn't hold
return c;
}
/**
* @dev Subtracts two numbers, throws on overflow (i.e. if subtrahend is greater than minuend).
*/
function sub(uint256 a, uint256 b) internal pure returns (uint256) {
assert(b <= a);
return a - b;
}
/**
* @dev Adds two numbers, throws on overflow.
*/
function add(uint256 a, uint256 b) internal pure returns (uint256) {
uint256 c = a + b;
assert(c >= a);
return c;
}
}
/**
* @title SafeMath32
* @dev SafeMath library implemented for uint32
*/
library SafeMath32 {
function mul(uint32 a, uint32 b) internal pure returns (uint32) {
if (a == 0) {
return 0;
}
uint32 c = a * b;
assert(c / a == b);
return c;
}
function div(uint32 a, uint32 b) internal pure returns (uint32) {
// assert(b > 0); // Solidity automatically throws when dividing by 0
uint32 c = a / b;
// assert(a == b * c + a % b); // There is no case in which this doesn't hold
return c;
}
function sub(uint32 a, uint32 b) internal pure returns (uint32) {
assert(b <= a);
return a - b;
}
function add(uint32 a, uint32 b) internal pure returns (uint32) {
uint32 c = a + b;
assert(c >= a);
return c;
}
}
/**
* @title SafeMath16
* @dev SafeMath library implemented for uint16
*/
library SafeMath16 {
function mul(uint16 a, uint16 b) internal pure returns (uint16) {
if (a == 0) {
return 0;
}
uint16 c = a * b;
assert(c / a == b);
return c;
}
function div(uint16 a, uint16 b) internal pure returns (uint16) {
// assert(b > 0); // Solidity automatically throws when dividing by 0
uint16 c = a / b;
// assert(a == b * c + a % b); // There is no case in which this doesn't hold
return c;
}
function sub(uint16 a, uint16 b) internal pure returns (uint16) {
assert(b <= a);
return a - b;
}
function add(uint16 a, uint16 b) internal pure returns (uint16) {
uint16 c = a + b;
assert(c >= a);
return c;
}
}