cppcheck/lib/calculate.h

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/*
* Cppcheck - A tool for static C/C++ code analysis
2023-09-04 19:44:27 +02:00
* Copyright (C) 2007-2023 Cppcheck team.
*
* This program 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.
*
* This program 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 this program. If not, see <http://www.gnu.org/licenses/>.
*/
#ifndef calculateH
#define calculateH
#include "mathlib.h"
#include "errortypes.h"
#include <limits>
#include <string>
template<class T>
bool isEqual(T x, T y)
{
return x == y;
}
inline bool isEqual(double x, double y)
{
const double diff = (x > y) ? x - y : y - x;
return !((diff / 2) < diff);
}
inline bool isEqual(float x, float y)
{
return isEqual(double(x), double(y));
}
template<class T>
bool isZero(T x)
{
return isEqual(x, T(0));
}
template<class R, class T>
R calculate(const std::string& s, const T& x, const T& y, bool* error = nullptr)
{
auto wrap = [](T z) {
return R{z};
};
const MathLib::bigint maxBitsShift = sizeof(MathLib::bigint) * 8;
// For portability we cannot shift signed integers by 63 bits
const MathLib::bigint maxBitsSignedShift = maxBitsShift - 1;
switch (MathLib::encodeMultiChar(s)) {
case '+':
return wrap(x + y);
case '-':
return wrap(x - y);
case '*':
return wrap(x * y);
case '/':
if (isZero(y) || (std::is_integral<T>{} && std::is_signed<T>{} && isEqual(y, T(-1)) && isEqual(x, std::numeric_limits<T>::min()))) {
if (error)
*error = true;
return R{};
}
return wrap(x / y);
case '%':
if (isZero(MathLib::bigint(y)) || (std::is_integral<T>{} && std::is_signed<T>{} && isEqual(y, T(-1)) && isEqual(x, std::numeric_limits<T>::min()))) {
if (error)
*error = true;
return R{};
}
return wrap(MathLib::bigint(x) % MathLib::bigint(y));
case '&':
return wrap(MathLib::bigint(x) & MathLib::bigint(y));
case '|':
return wrap(MathLib::bigint(x) | MathLib::bigint(y));
case '^':
return wrap(MathLib::bigint(x) ^ MathLib::bigint(y));
case '>':
return wrap(x > y);
case '<':
return wrap(x < y);
case '<<':
if (y >= maxBitsSignedShift || y < 0 || x < 0) {
if (error)
*error = true;
return R{};
}
return wrap(MathLib::bigint(x) << MathLib::bigint(y));
case '>>':
if (y >= maxBitsSignedShift || y < 0 || x < 0) {
if (error)
*error = true;
return R{};
}
return wrap(MathLib::bigint(x) >> MathLib::bigint(y));
case '&&':
return wrap(!isZero(x) && !isZero(y));
case '||':
return wrap(!isZero(x) || !isZero(y));
case '==':
return wrap(isEqual(x, y));
case '!=':
return wrap(!isEqual(x, y));
case '>=':
return wrap(x >= y);
case '<=':
return wrap(x <= y);
case '<=>':
return wrap(x - y);
}
throw InternalError(nullptr, "Unknown operator: " + s);
}
template<class T>
T calculate(const std::string& s, const T& x, const T& y, bool* error = nullptr)
{
return calculate<T, T>(s, x, y, error);
}
#endif