64 lines
1.4 KiB
Solidity
64 lines
1.4 KiB
Solidity
/*
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Copyright 2020 DODO ZOO.
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SPDX-License-Identifier: Apache-2.0
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*/
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pragma solidity 0.6.9;
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pragma experimental ABIEncoderV2;
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/**
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* @title SafeMath
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* @author DODO Breeder
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*
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* @notice Math operations with safety checks that revert on error
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*/
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library SafeMath {
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function mul(uint256 a, uint256 b) internal pure returns (uint256) {
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if (a == 0) {
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return 0;
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}
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uint256 c = a * b;
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require(c / a == b, "MUL_ERROR");
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return c;
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}
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function div(uint256 a, uint256 b) internal pure returns (uint256) {
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require(b > 0, "DIVIDING_ERROR");
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return a / b;
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}
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function divCeil(uint256 a, uint256 b) internal pure returns (uint256) {
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uint256 quotient = div(a, b);
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uint256 remainder = a - quotient * b;
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if (remainder > 0) {
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return quotient + 1;
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} else {
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return quotient;
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}
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}
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function sub(uint256 a, uint256 b) internal pure returns (uint256) {
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require(b <= a, "SUB_ERROR");
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return a - b;
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}
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function add(uint256 a, uint256 b) internal pure returns (uint256) {
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uint256 c = a + b;
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require(c >= a, "ADD_ERROR");
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return c;
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}
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function sqrt(uint256 x) internal pure returns (uint256 y) {
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uint256 z = (x + 1) / 2;
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y = x;
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while (z < y) {
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y = z;
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z = (x / z + z) / 2;
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}
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}
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}
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