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pragma solidity 0.4.24;
contract SafeMath {
function safeMul(uint256 a, uint256 b)
internal
pure
returns (uint256)
{
if (a == 0) {
return 0;
}
uint256 c = a * b;
require(
c / a == b,
"UINT256_OVERFLOW"
);
return c;
}
function safeDiv(uint256 a, uint256 b)
internal
pure
returns (uint256)
{
uint256 c = a / b;
return c;
}
function safeSub(uint256 a, uint256 b)
internal
pure
returns (uint256)
{
require(
b <= a,
"UINT256_UNDERFLOW"
);
return a - b;
}
function safeAdd(uint256 a, uint256 b)
internal
pure
returns (uint256)
{
uint256 c = a + b;
require(
c >= a,
"UINT256_OVERFLOW"
);
return c;
}
function max64(uint64 a, uint64 b)
internal
pure
returns (uint256)
{
return a >= b ? a : b;
}
function min64(uint64 a, uint64 b)
internal
pure
returns (uint256)
{
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;
}
}
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