18 lines
562 B
Solidity
18 lines
562 B
Solidity
pragma solidity =0.6.6;
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// a library for performing overflow-safe math, courtesy of DappHub (https://github.com/dapphub/ds-math)
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library SafeMath {
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function add(uint x, uint y) internal pure returns (uint z) {
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require((z = x + y) >= x, 'ds-math-add-overflow');
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}
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function sub(uint x, uint y) internal pure returns (uint z) {
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require((z = x - y) <= x, 'ds-math-sub-underflow');
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}
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function mul(uint x, uint y) internal pure returns (uint z) {
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require(y == 0 || (z = x * y) / y == x, 'ds-math-mul-overflow');
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}
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}
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