//

// Copyright 2017 The Abseil Authors.

//

// Licensed under the Apache License, Version 2.0 (the "License");

// you may not use this file except in compliance with the License.

// You may obtain a copy of the License at

//

//      https://www.apache.org/licenses/LICENSE-2.0

//

// Unless required by applicable law or agreed to in writing, software

// distributed under the License is distributed on an "AS IS" BASIS,

// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

// See the License for the specific language governing permissions and

// limitations under the License.

// This file contains :int128 implementation details that depend on internal

// representation when ABSL_HAVE_INTRINSIC_INT128 is defined. This file is

// included by int128.h and relies on ABSL_INTERNAL_WCHAR_T being defined.

namespace int128_internal {

// Casts from unsigned to signed while preserving the underlying binary

// representation.

constexpr __int128 BitCastToSigned(unsigned __int128 v) {

  // Casting an unsigned integer to a signed integer of the same

  // width is implementation defined behavior if the source value would not fit

  // in the destination type. We step around it with a roundtrip bitwise not

  // operation to make sure this function remains constexpr. Clang and GCC

  // optimize this to a no-op on x86-64.

  return v & (static_cast<unsigned __int128>(1) << 127)

             ? ~static_cast<__int128>(~v)

             : static_cast<__int128>(v);

}

}  // namespace int128_internal

inline int128& int128::operator=(__int128 v) {

  v_ = v;

  return *this;

}

constexpr uint64_t Int128Low64(int128 v) {

  return static_cast<uint64_t>(v.v_ & ~uint64_t{0});

}

constexpr int64_t Int128High64(int128 v) {

  // Initially cast to unsigned to prevent a right shift on a negative value.

  return int128_internal::BitCastToSigned(

      static_cast<uint64_t>(static_cast<unsigned __int128>(v.v_) >> 64));

}

constexpr int128::int128(int64_t high, uint64_t low)

    // Initially cast to unsigned to prevent a left shift that overflows.

    : v_(int128_internal::BitCastToSigned(static_cast<unsigned __int128>(high)

                                           << 64) |

         low) {}

constexpr int128::int128(int v) : v_{v} {}

constexpr int128::int128(long v) : v_{v} {}       // NOLINT(runtime/int)

constexpr int128::int128(long long v) : v_{v} {}  // NOLINT(runtime/int)

constexpr int128::int128(__int128 v) : v_{v} {}

constexpr int128::int128(unsigned int v) : v_{v} {}

constexpr int128::int128(unsigned long v) : v_{v} {}  // NOLINT(runtime/int)

// NOLINTNEXTLINE(runtime/int)

constexpr int128::int128(unsigned long long v) : v_{v} {}

constexpr int128::int128(unsigned __int128 v) : v_{static_cast<__int128>(v)} {}

inline int128::int128(float v) {

  v_ = static_cast<__int128>(v);

}

inline int128::int128(double v) {

  v_ = static_cast<__int128>(v);

}

inline int128::int128(long double v) {

  v_ = static_cast<__int128>(v);

}

constexpr int128::int128(uint128 v) : v_{static_cast<__int128>(v)} {}

constexpr int128::operator bool() const { return static_cast<bool>(v_); }

constexpr int128::operator char() const { return static_cast<char>(v_); }

constexpr int128::operator signed char() const {

  return static_cast<signed char>(v_);

}

constexpr int128::operator unsigned char() const {

  return static_cast<unsigned char>(v_);

}

constexpr int128::operator char16_t() const {

  return static_cast<char16_t>(v_);

}

constexpr int128::operator char32_t() const {

  return static_cast<char32_t>(v_);

}

constexpr int128::operator ABSL_INTERNAL_WCHAR_T() const {

  return static_cast<ABSL_INTERNAL_WCHAR_T>(v_);

}

constexpr int128::operator short() const {  // NOLINT(runtime/int)

  return static_cast<short>(v_);            // NOLINT(runtime/int)

}

constexpr int128::operator unsigned short() const {  // NOLINT(runtime/int)

  return static_cast<unsigned short>(v_);            // NOLINT(runtime/int)

}

constexpr int128::operator int() const {

  return static_cast<int>(v_);

}

constexpr int128::operator unsigned int() const {

  return static_cast<unsigned int>(v_);

}

constexpr int128::operator long() const {  // NOLINT(runtime/int)

  return static_cast<long>(v_);            // NOLINT(runtime/int)

}

constexpr int128::operator unsigned long() const {  // NOLINT(runtime/int)

  return static_cast<unsigned long>(v_);            // NOLINT(runtime/int)

}

constexpr int128::operator long long() const {  // NOLINT(runtime/int)

  return static_cast<long long>(v_);            // NOLINT(runtime/int)

}

constexpr int128::operator unsigned long long() const {  // NOLINT(runtime/int)

  return static_cast<unsigned long long>(v_);            // NOLINT(runtime/int)

}

constexpr int128::operator __int128() const { return v_; }

constexpr int128::operator unsigned __int128() const {

  return static_cast<unsigned __int128>(v_);

}

// Clang on PowerPC sometimes produces incorrect __int128 to floating point

// conversions. In that case, we do the conversion with a similar implementation

// to the conversion operators in int128_no_intrinsic.inc.

#if defined(__clang__) && !defined(__ppc64__)

inline int128::operator float() const { return static_cast<float>(v_); }

inline int128::operator double() const { return static_cast<double>(v_); }

inline int128::operator long double() const {

  return static_cast<long double>(v_);

}

#else  // Clang on PowerPC

inline int128::operator float() const {

  // We must convert the absolute value and then negate as needed, because

  // floating point types are typically sign-magnitude. Otherwise, the

  // difference between the high and low 64 bits when interpreted as two's

  // complement overwhelms the precision of the mantissa.

  //

  // Also check to make sure we don't negate Int128Min()

  return v_ < 0 && *this != Int128Min()

             ? -static_cast<float>(-*this)

             : static_cast<float>(Int128Low64(*this)) +

                   std::ldexp(static_cast<float>(Int128High64(*this)), 64);

}

inline int128::operator double() const {

  // See comment in int128::operator float() above.

  return v_ < 0 && *this != Int128Min()

             ? -static_cast<double>(-*this)

             : static_cast<double>(Int128Low64(*this)) +

                   std::ldexp(static_cast<double>(Int128High64(*this)), 64);

}

inline int128::operator long double() const {

  // See comment in int128::operator float() above.

  return v_ < 0 && *this != Int128Min()

             ? -static_cast<long double>(-*this)

             : static_cast<long double>(Int128Low64(*this)) +

                   std::ldexp(static_cast<long double>(Int128High64(*this)),

                              64);

}

#endif  // Clang on PowerPC

// Comparison operators.

constexpr bool operator==(int128 lhs, int128 rhs) {

  return static_cast<__int128>(lhs) == static_cast<__int128>(rhs);

}

constexpr bool operator!=(int128 lhs, int128 rhs) {

  return static_cast<__int128>(lhs) != static_cast<__int128>(rhs);

}

constexpr bool operator<(int128 lhs, int128 rhs) {

  return static_cast<__int128>(lhs) < static_cast<__int128>(rhs);

}

constexpr bool operator>(int128 lhs, int128 rhs) {

  return static_cast<__int128>(lhs) > static_cast<__int128>(rhs);

}

constexpr bool operator<=(int128 lhs, int128 rhs) {

  return static_cast<__int128>(lhs) <= static_cast<__int128>(rhs);

}

constexpr bool operator>=(int128 lhs, int128 rhs) {

  return static_cast<__int128>(lhs) >= static_cast<__int128>(rhs);

}

#ifdef __cpp_impl_three_way_comparison

constexpr absl::strong_ordering operator<=>(int128 lhs, int128 rhs) {

  if (auto lhs_128 = static_cast<__int128>(lhs),

      rhs_128 = static_cast<__int128>(rhs);

      lhs_128 < rhs_128) {

    return absl::strong_ordering::less;

  } else if (lhs_128 > rhs_128) {

    return absl::strong_ordering::greater;

  } else {

    return absl::strong_ordering::equal;

  }

}

#endif

// Unary operators.

constexpr int128 operator-(int128 v) { return -static_cast<__int128>(v); }

constexpr bool operator!(int128 v) { return !static_cast<__int128>(v); }

constexpr int128 operator~(int128 val) { return ~static_cast<__int128>(val); }

// Arithmetic operators.

constexpr int128 operator+(int128 lhs, int128 rhs) {

  return static_cast<__int128>(lhs) + static_cast<__int128>(rhs);

}

constexpr int128 operator-(int128 lhs, int128 rhs) {

  return static_cast<__int128>(lhs) - static_cast<__int128>(rhs);

}

inline int128 operator*(int128 lhs, int128 rhs) {

  return static_cast<__int128>(lhs) * static_cast<__int128>(rhs);

}

inline int128 operator/(int128 lhs, int128 rhs) {

  return static_cast<__int128>(lhs) / static_cast<__int128>(rhs);

}

inline int128 operator%(int128 lhs, int128 rhs) {

  return static_cast<__int128>(lhs) % static_cast<__int128>(rhs);

}

inline int128 int128::operator++(int) {

  int128 tmp(*this);

  ++v_;

  return tmp;

}

inline int128 int128::operator--(int) {

  int128 tmp(*this);

  --v_;

  return tmp;

}

inline int128& int128::operator++() {

  ++v_;

  return *this;

}

inline int128& int128::operator--() {

  --v_;

  return *this;

}

constexpr int128 operator|(int128 lhs, int128 rhs) {

  return static_cast<__int128>(lhs) | static_cast<__int128>(rhs);

}

constexpr int128 operator&(int128 lhs, int128 rhs) {

  return static_cast<__int128>(lhs) & static_cast<__int128>(rhs);

}

constexpr int128 operator^(int128 lhs, int128 rhs) {

  return static_cast<__int128>(lhs) ^ static_cast<__int128>(rhs);

}

constexpr int128 operator<<(int128 lhs, int amount) {

  return static_cast<__int128>(lhs) << amount;

}

constexpr int128 operator>>(int128 lhs, int amount) {

  return static_cast<__int128>(lhs) >> amount;

}