solidity/libsolutil/Numeric.cpp

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/*
This file is part of solidity.
solidity is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
solidity is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with solidity. If not, see <http://www.gnu.org/licenses/>.
*/
// SPDX-License-Identifier: GPL-3.0
2021-09-16 14:33:28 +00:00
#include <libsolutil/Numeric.h>
#include <liblangutil/Exceptions.h>
using namespace solidity;
bool solidity::fitsPrecisionBaseX(bigint const& _mantissa, double _log2OfBase, uint32_t _exp)
{
if (_mantissa == 0)
return true;
solAssert(_mantissa > 0, "");
size_t const bitsMax = 4096;
unsigned mostSignificantMantissaBit = boost::multiprecision::msb(_mantissa);
if (mostSignificantMantissaBit > bitsMax) // _mantissa >= 2 ^ 4096
return false;
bigint bitsNeeded = mostSignificantMantissaBit + bigint(floor(double(_exp) * _log2OfBase)) + 1;
return bitsNeeded <= bitsMax;
}