third_party/WebKit/Source/platform/wtf/SaturatedArithmetic.h

/*
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#ifndef SaturatedArithmetic_h
#define SaturatedArithmetic_h

#include "base/compiler_specific.h"
#include "base/numerics/clamped_math.h"
#include "build/build_config.h"

#include <stdint.h>

#include <limits>

#if defined(ARCH_CPU_ARM_FAMILY) && defined(ARCH_CPU_32_BITS) && \
    defined(COMPILER_GCC) && !defined(OS_NACL) && __OPTIMIZE__

// If we're building ARM 32-bit on GCC we replace the C++ versions with some
// native ARM assembly for speed.
#include "platform/wtf/SaturatedArithmeticARM.h"

#else

namespace WTF {

ALWAYS_INLINE int GetMaxSaturatedSetResultForTesting(int fractional_shift) {
  // For C version the set function maxes out to max int, this differs from
  // the ARM asm version, see saturated_arithmetic_arm.h for the equivalent asm
  // version.
  return std::numeric_limits<int>::max();
}

ALWAYS_INLINE int GetMinSaturatedSetResultForTesting(int fractional_shift) {
  return std::numeric_limits<int>::min();
}

template <int fractional_shift>
ALWAYS_INLINE int SaturatedSet(int value) {
  const int kIntMaxForLayoutUnit =
      std::numeric_limits<int>::max() >> fractional_shift;

  const int kIntMinForLayoutUnit =
      std::numeric_limits<int>::min() >> fractional_shift;

  if (value > kIntMaxForLayoutUnit)
    return std::numeric_limits<int>::max();

  if (value < kIntMinForLayoutUnit)
    return std::numeric_limits<int>::min();

  return static_cast<unsigned>(value) << fractional_shift;
}

template <int fractional_shift>
ALWAYS_INLINE int SaturatedSet(unsigned value) {
  const unsigned kIntMaxForLayoutUnit =
      std::numeric_limits<int>::max() >> fractional_shift;

  if (value >= kIntMaxForLayoutUnit)
    return std::numeric_limits<int>::max();

  return value << fractional_shift;
}

}  // namespace WTF.

#endif  // CPU(ARM) && COMPILER(GCC)

namespace WTF {
using base::ClampAdd;
using base::ClampSub;
using base::MakeClampedNum;
}  // namespace WTF.

using WTF::ClampAdd;
using WTF::ClampSub;
using WTF::MakeClampedNum;
using WTF::SaturatedSet;

#endif  // SaturatedArithmetic_h