chromium/v8/src/base/overflowing-math.h

// Copyright 2019 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef V8_BASE_OVERFLOWING_MATH_H_
#define V8_BASE_OVERFLOWING_MATH_H_

#include <stdint.h>

#include <cmath>
#include <type_traits>

#include "src/base/macros.h"

namespace v8 {
namespace base {

// Helpers for performing overflowing arithmetic operations without relying
// on C++ undefined behavior.
#define ASSERT_SIGNED_INTEGER_TYPE …
#define OP_WITH_WRAPAROUND …

OP_WITH_WRAPAROUND
OP_WITH_WRAPAROUND
OP_WITH_WRAPAROUND

// 16-bit integers are special due to C++'s implicit conversion rules.
// See https://bugs.llvm.org/show_bug.cgi?id=25580.
template <>
inline int16_t MulWithWraparound(int16_t a, int16_t b) { … }

#undef OP_WITH_WRAPAROUND

template <typename signed_type>
inline signed_type NegateWithWraparound(signed_type a) { … }

template <typename signed_type>
inline signed_type ShlWithWraparound(signed_type a, signed_type b) { … }

#undef ASSERT_SIGNED_INTEGER_TYPE

// Returns the quotient x/y, avoiding C++ undefined behavior if y == 0.
template <typename T>
inline T Divide(T x, T y) { … }

inline float Recip(float a) { … }

inline float RecipSqrt(float a) { … }

}  // namespace base
}  // namespace v8

#endif  // V8_BASE_OVERFLOWING_MATH_H_