// // 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 // // http://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. // // ----------------------------------------------------------------------------- // File: int128.h // ----------------------------------------------------------------------------- // // This header file defines 128-bit integer types. // // Currently, this file defines `uint128`, an unsigned 128-bit integer; a signed // 128-bit integer is forthcoming. #ifndef ABSL_NUMERIC_INT128_H_ #define ABSL_NUMERIC_INT128_H_ #include #include #include #include #include #include #include "absl/base/config.h" #include "absl/base/macros.h" #include "absl/base/port.h" namespace absl { // uint128 // // An unsigned 128-bit integer type. The API is meant to mimic an intrinsic type // as closely as is practical, including exhibiting undefined behavior in // analogous cases (e.g. division by zero). This type is intended to be a // drop-in replacement once C++ supports an intrinsic `uint128_t` type; when // that occurs, existing well-behaved uses of `uint128` will continue to work // using that new type. // // Note: code written with this type will continue to compile once `uint128_t` // is introduced, provided the replacement helper functions // `Uint128(Low|High)64()` and `MakeUint128()` are made. // // A `uint128` supports the following: // // * Implicit construction from integral types // * Explicit conversion to integral types // // Additionally, if your compiler supports `__int128`, `uint128` is // interoperable with that type. (Abseil checks for this compatibility through // the `ABSL_HAVE_INTRINSIC_INT128` macro.) // // However, a `uint128` differs from intrinsic integral types in the following // ways: // // * Errors on implicit conversions that do not preserve value (such as // loss of precision when converting to float values). // * Requires explicit construction from and conversion to floating point // types. // * Conversion to integral types requires an explicit static_cast() to // mimic use of the `-Wnarrowing` compiler flag. // * The alignment requirement of `uint128` may differ from that of an // intrinsic 128-bit integer type depending on platform and build // configuration. // // Example: // // float y = absl::Uint128Max(); // Error. uint128 cannot be implicitly // // converted to float. // // absl::uint128 v; // uint64_t i = v; // Error // uint64_t i = static_cast(v); // OK // class #if defined(ABSL_HAVE_INTRINSIC_INT128) alignas(unsigned __int128) #endif // ABSL_HAVE_INTRINSIC_INT128 uint128 { public: uint128() = default; // Constructors from arithmetic types constexpr uint128(int v); // NOLINT(runtime/explicit) constexpr uint128(unsigned int v); // NOLINT(runtime/explicit) constexpr uint128(long v); // NOLINT(runtime/int) constexpr uint128(unsigned long v); // NOLINT(runtime/int) constexpr uint128(long long v); // NOLINT(runtime/int) constexpr uint128(unsigned long long v); // NOLINT(runtime/int) #ifdef ABSL_HAVE_INTRINSIC_INT128 constexpr uint128(__int128 v); // NOLINT(runtime/explicit) constexpr uint128(unsigned __int128 v); // NOLINT(runtime/explicit) #endif // ABSL_HAVE_INTRINSIC_INT128 explicit uint128(float v); explicit uint128(double v); explicit uint128(long double v); // Assignment operators from arithmetic types uint128& operator=(int v); uint128& operator=(unsigned int v); uint128& operator=(long v); // NOLINT(runtime/int) uint128& operator=(unsigned long v); // NOLINT(runtime/int) uint128& operator=(long long v); // NOLINT(runtime/int) uint128& operator=(unsigned long long v); // NOLINT(runtime/int) #ifdef ABSL_HAVE_INTRINSIC_INT128 uint128& operator=(__int128 v); uint128& operator=(unsigned __int128 v); #endif // ABSL_HAVE_INTRINSIC_INT128 // Conversion operators to other arithmetic types constexpr explicit operator bool() const; constexpr explicit operator char() const; constexpr explicit operator signed char() const; constexpr explicit operator unsigned char() const; constexpr explicit operator char16_t() const; constexpr explicit operator char32_t() const; constexpr explicit operator wchar_t() const; constexpr explicit operator short() const; // NOLINT(runtime/int) // NOLINTNEXTLINE(runtime/int) constexpr explicit operator unsigned short() const; constexpr explicit operator int() const; constexpr explicit operator unsigned int() const; constexpr explicit operator long() const; // NOLINT(runtime/int) // NOLINTNEXTLINE(runtime/int) constexpr explicit operator unsigned long() const; // NOLINTNEXTLINE(runtime/int) constexpr explicit operator long long() const; // NOLINTNEXTLINE(runtime/int) constexpr explicit operator unsigned long long() const; #ifdef ABSL_HAVE_INTRINSIC_INT128 constexpr explicit operator __int128() const; constexpr explicit operator unsigned __int128() const; #endif // ABSL_HAVE_INTRINSIC_INT128 explicit operator float() const; explicit operator double() const; explicit operator long double() const; // Trivial copy constructor, assignment operator and destructor. // Arithmetic operators. uint128& operator+=(uint128 other); uint128& operator-=(uint128 other); uint128& operator*=(uint128 other); // Long division/modulo for uint128. uint128& operator/=(uint128 other); uint128& operator%=(uint128 other); uint128 operator++(int); uint128 operator--(int); uint128& operator<<=(int); uint128& operator>>=(int); uint128& operator&=(uint128 other); uint128& operator|=(uint128 other); uint128& operator^=(uint128 other); uint128& operator++(); uint128& operator--(); // Uint128Low64() // // Returns the lower 64-bit value of a `uint128` value. friend constexpr uint64_t Uint128Low64(uint128 v); // Uint128High64() // // Returns the higher 64-bit value of a `uint128` value. friend constexpr uint64_t Uint128High64(uint128 v); // MakeUInt128() // // Constructs a `uint128` numeric value from two 64-bit unsigned integers. // Note that this factory function is the only way to construct a `uint128` // from integer values greater than 2^64. // // Example: // // absl::uint128 big = absl::MakeUint128(1, 0); friend constexpr uint128 MakeUint128(uint64_t high, uint64_t low); // Uint128Max() // // Returns the highest value for a 128-bit unsigned integer. friend constexpr uint128 Uint128Max(); private: constexpr uint128(uint64_t high, uint64_t low); // TODO(strel) Update implementation to use __int128 once all users of // uint128 are fixed to not depend on alignof(uint128) == 8. Also add // alignas(16) to class definition to keep alignment consistent across // platforms. #if defined(ABSL_IS_LITTLE_ENDIAN) uint64_t lo_; uint64_t hi_; #elif defined(ABSL_IS_BIG_ENDIAN) uint64_t hi_; uint64_t lo_; #else // byte order #error "Unsupported byte order: must be little-endian or big-endian." #endif // byte order }; // Prefer to use the constexpr `Uint128Max()`. // // TODO(absl-team) deprecate kuint128max once migration tool is released. extern const uint128 kuint128max; // allow uint128 to be logged std::ostream& operator<<(std::ostream& os, uint128 v); // TODO(strel) add operator>>(std::istream&, uint128) constexpr uint128 Uint128Max() { return uint128(std::numeric_limits::max(), std::numeric_limits::max()); } } // namespace absl // Specialized numeric_limits for uint128. namespace std { template <> class numeric_limits { public: static constexpr bool is_specialized = true; static constexpr bool is_signed = false; static constexpr bool is_integer = true; static constexpr bool is_exact = true; static constexpr bool has_infinity = false; static constexpr bool has_quiet_NaN = false; static constexpr bool has_signaling_NaN = false; static constexpr float_denorm_style has_denorm = denorm_absent; static constexpr bool has_denorm_loss = false; static constexpr float_round_style round_style = round_toward_zero; static constexpr bool is_iec559 = false; static constexpr bool is_bounded = true; static constexpr bool is_modulo = true; static constexpr int digits = 128; static constexpr int digits10 = 38; static constexpr int max_digits10 = 0; static constexpr int radix = 2; static constexpr int min_exponent = 0; static constexpr int min_exponent10 = 0; static constexpr int max_exponent = 0; static constexpr int max_exponent10 = 0; #ifdef ABSL_HAVE_INTRINSIC_INT128 static constexpr bool traps = numeric_limits::traps; #else // ABSL_HAVE_INTRINSIC_INT128 static constexpr bool traps = numeric_limits::traps; #endif // ABSL_HAVE_INTRINSIC_INT128 static constexpr bool tinyness_before = false; static constexpr absl::uint128 min() { return 0; } static constexpr absl::uint128 lowest() { return 0; } static constexpr absl::uint128 max() { return absl::Uint128Max(); } static constexpr absl::uint128 epsilon() { return 0; } static constexpr absl::uint128 round_error() { return 0; } static constexpr absl::uint128 infinity() { return 0; } static constexpr absl::uint128 quiet_NaN() { return 0; } static constexpr absl::uint128 signaling_NaN() { return 0; } static constexpr absl::uint128 denorm_min() { return 0; } }; } // namespace std // TODO(absl-team): Implement signed 128-bit type // -------------------------------------------------------------------------- // Implementation details follow // -------------------------------------------------------------------------- namespace absl { constexpr uint128 MakeUint128(uint64_t high, uint64_t low) { return uint128(high, low); } // Assignment from integer types. inline uint128& uint128::operator=(int v) { return *this = uint128(v); } inline uint128& uint128::operator=(unsigned int v) { return *this = uint128(v); } inline uint128& uint128::operator=(long v) { // NOLINT(runtime/int) return *this = uint128(v); } // NOLINTNEXTLINE(runtime/int) inline uint128& uint128::operator=(unsigned long v) { return *this = uint128(v); } // NOLINTNEXTLINE(runtime/int) inline uint128& uint128::operator=(long long v) { return *this = uint128(v); } // NOLINTNEXTLINE(runtime/int) inline uint128& uint128::operator=(unsigned long long v) { return *this = uint128(v); } #ifdef ABSL_HAVE_INTRINSIC_INT128 inline uint128& uint128::operator=(__int128 v) { return *this = uint128(v); } inline uint128& uint128::operator=(unsigned __int128 v) { return *this = uint128(v); } #endif // ABSL_HAVE_INTRINSIC_INT128 // Arithmetic operators. uint128 operator<<(uint128 lhs, int amount); uint128 operator>>(uint128 lhs, int amount); uint128 operator+(uint128 lhs, uint128 rhs); uint128 operator-(uint128 lhs, uint128 rhs); uint128 operator*(uint128 lhs, uint128 rhs); uint128 operator/(uint128 lhs, uint128 rhs); uint128 operator%(uint128 lhs, uint128 rhs); inline uint128& uint128::operator<<=(int amount) { *this = *this << amount; return *this; } inline uint128& uint128::operator>>=(int amount) { *this = *this >> amount; return *this; } inline uint128& uint128::operator+=(uint128 other) { *this = *this + other; return *this; } inline uint128& uint128::operator-=(uint128 other) { *this = *this - other; return *this; } inline uint128& uint128::operator*=(uint128 other) { *this = *this * other; return *this; } inline uint128& uint128::operator/=(uint128 other) { *this = *this / other; return *this; } inline uint128& uint128::operator%=(uint128 other) { *this = *this % other; return *this; } constexpr uint64_t Uint128Low64(uint128 v) { return v.lo_; } constexpr uint64_t Uint128High64(uint128 v) { return v.hi_; } // Constructors from integer types. #if defined(ABSL_IS_LITTLE_ENDIAN) constexpr uint128::uint128(uint64_t high, uint64_t low) : lo_{low}, hi_{high} {} constexpr uint128::uint128(int v) : lo_{static_cast(v)}, hi_{v < 0 ? std::numeric_limits::max() : 0} {} constexpr uint128::uint128(long v) // NOLINT(runtime/int) : lo_{static_cast(v)}, hi_{v < 0 ? std::numeric_limits::max() : 0} {} constexpr uint128::uint128(long long v) // NOLINT(runtime/int) : lo_{static_cast(v)}, hi_{v < 0 ? std::numeric_limits::max() : 0} {} constexpr uint128::uint128(unsigned int v) : lo_{v}, hi_{0} {} // NOLINTNEXTLINE(runtime/int) constexpr uint128::uint128(unsigned long v) : lo_{v}, hi_{0} {} // NOLINTNEXTLINE(runtime/int) constexpr uint128::uint128(unsigned long long v) : lo_{v}, hi_{0} {} #ifdef ABSL_HAVE_INTRINSIC_INT128 constexpr uint128::uint128(__int128 v) : lo_{static_cast(v & ~uint64_t{0})}, hi_{static_cast(static_cast(v) >> 64)} {} constexpr uint128::uint128(unsigned __int128 v) : lo_{static_cast(v & ~uint64_t{0})}, hi_{static_cast(v >> 64)} {} #endif // ABSL_HAVE_INTRINSIC_INT128 #elif defined(ABSL_IS_BIG_ENDIAN) constexpr uint128::uint128(uint64_t high, uint64_t low) : hi_{high}, lo_{low} {} constexpr uint128::uint128(int v) : hi_{v < 0 ? std::numeric_limits::max() : 0}, lo_{static_cast(v)} {} constexpr uint128::uint128(long v) // NOLINT(runtime/int) : hi_{v < 0 ? std::numeric_limits::max() : 0}, lo_{static_cast(v)} {} constexpr uint128::uint128(long long v) // NOLINT(runtime/int) : hi_{v < 0 ? std::numeric_limits::max() : 0}, lo_{static_cast(v)} {} constexpr uint128::uint128(unsigned int v) : hi_{0}, lo_{v} {} // NOLINTNEXTLINE(runtime/int) constexpr uint128::uint128(unsigned long v) : hi_{0}, lo_{v} {} // NOLINTNEXTLINE(runtime/int) constexpr uint128::uint128(unsigned long long v) : hi_{0}, lo_{v} {} #ifdef ABSL_HAVE_INTRINSIC_INT128 constexpr uint128::uint128(__int128 v) : hi_{static_cast(static_cast(v) >> 64)}, lo_{static_cast(v & ~uint64_t{0})} {} constexpr uint128::uint128(unsigned __int128 v) : hi_{static_cast(v >> 64)}, lo_{static_cast(v & ~uint64_t{0})} {} #endif // ABSL_HAVE_INTRINSIC_INT128 #else // byte order #error "Unsupported byte order: must be little-endian or big-endian." #endif // byte order // Conversion operators to integer types. constexpr uint128::operator bool() const { return lo_ || hi_; } constexpr uint128::operator char() const { return static_cast(lo_); } constexpr uint128::operator signed char() const { return static_cast(lo_); } constexpr uint128::operator unsigned char() const { return static_cast(lo_); } constexpr uint128::operator char16_t() const { return static_cast(lo_); } constexpr uint128::operator char32_t() const { return static_cast(lo_); } constexpr uint128::operator wchar_t() const { return static_cast(lo_); } // NOLINTNEXTLINE(runtime/int) constexpr uint128::operator short() const { return static_cast(lo_); } constexpr uint128::operator unsigned short() const { // NOLINT(runtime/int) return static_cast(lo_); // NOLINT(runtime/int) } constexpr uint128::operator int() const { return static_cast(lo_); } constexpr uint128::operator unsigned int() const { return static_cast(lo_); } // NOLINTNEXTLINE(runtime/int) constexpr uint128::operator long() const { return static_cast(lo_); } constexpr uint128::operator unsigned long() const { // NOLINT(runtime/int) return static_cast(lo_); // NOLINT(runtime/int) } constexpr uint128::operator long long() const { // NOLINT(runtime/int) return static_cast(lo_); // NOLINT(runtime/int) } constexpr uint128::operator unsigned long long() const { // NOLINT(runtime/int) return static_cast(lo_); // NOLINT(runtime/int) } #ifdef ABSL_HAVE_INTRINSIC_INT128 constexpr uint128::operator __int128() const { return (static_cast<__int128>(hi_) << 64) + lo_; } constexpr uint128::operator unsigned __int128() const { return (static_cast(hi_) << 64) + lo_; } #endif // ABSL_HAVE_INTRINSIC_INT128 // Conversion operators to floating point types. inline uint128::operator float() const { return static_cast(lo_) + std::ldexp(static_cast(hi_), 64); } inline uint128::operator double() const { return static_cast(lo_) + std::ldexp(static_cast(hi_), 64); } inline uint128::operator long double() const { return static_cast(lo_) + std::ldexp(static_cast(hi_), 64); } // Comparison operators. inline bool operator==(uint128 lhs, uint128 rhs) { return (Uint128Low64(lhs) == Uint128Low64(rhs) && Uint128High64(lhs) == Uint128High64(rhs)); } inline bool operator!=(uint128 lhs, uint128 rhs) { return !(lhs == rhs); } inline bool operator<(uint128 lhs, uint128 rhs) { return (Uint128High64(lhs) == Uint128High64(rhs)) ? (Uint128Low64(lhs) < Uint128Low64(rhs)) : (Uint128High64(lhs) < Uint128High64(rhs)); } inline bool operator>(uint128 lhs, uint128 rhs) { return (Uint128High64(lhs) == Uint128High64(rhs)) ? (Uint128Low64(lhs) > Uint128Low64(rhs)) : (Uint128High64(lhs) > Uint128High64(rhs)); } inline bool operator<=(uint128 lhs, uint128 rhs) { return (Uint128High64(lhs) == Uint128High64(rhs)) ? (Uint128Low64(lhs) <= Uint128Low64(rhs)) : (Uint128High64(lhs) <= Uint128High64(rhs)); } inline bool operator>=(uint128 lhs, uint128 rhs) { return (Uint128High64(lhs) == Uint128High64(rhs)) ? (Uint128Low64(lhs) >= Uint128Low64(rhs)) : (Uint128High64(lhs) >= Uint128High64(rhs)); } // Unary operators. inline uint128 operator-(uint128 val) { uint64_t hi = ~Uint128High64(val); uint64_t lo = ~Uint128Low64(val) + 1; if (lo == 0) ++hi; // carry return MakeUint128(hi, lo); } inline bool operator!(uint128 val) { return !Uint128High64(val) && !Uint128Low64(val); } // Logical operators. inline uint128 operator~(uint128 val) { return MakeUint128(~Uint128High64(val), ~Uint128Low64(val)); } inline uint128 operator|(uint128 lhs, uint128 rhs) { return MakeUint128(Uint128High64(lhs) | Uint128High64(rhs), Uint128Low64(lhs) | Uint128Low64(rhs)); } inline uint128 operator&(uint128 lhs, uint128 rhs) { return MakeUint128(Uint128High64(lhs) & Uint128High64(rhs), Uint128Low64(lhs) & Uint128Low64(rhs)); } inline uint128 operator^(uint128 lhs, uint128 rhs) { return MakeUint128(Uint128High64(lhs) ^ Uint128High64(rhs), Uint128Low64(lhs) ^ Uint128Low64(rhs)); } inline uint128& uint128::operator|=(uint128 other) { hi_ |= other.hi_; lo_ |= other.lo_; return *this; } inline uint128& uint128::operator&=(uint128 other) { hi_ &= other.hi_; lo_ &= other.lo_; return *this; } inline uint128& uint128::operator^=(uint128 other) { hi_ ^= other.hi_; lo_ ^= other.lo_; return *this; } // Arithmetic operators. inline uint128 operator<<(uint128 lhs, int amount) { // uint64_t shifts of >= 64 are undefined, so we will need some // special-casing. if (amount < 64) { if (amount != 0) { return MakeUint128( (Uint128High64(lhs) << amount) | (Uint128Low64(lhs) >> (64 - amount)), Uint128Low64(lhs) << amount); } return lhs; } return MakeUint128(Uint128Low64(lhs) << (amount - 64), 0); } inline uint128 operator>>(uint128 lhs, int amount) { // uint64_t shifts of >= 64 are undefined, so we will need some // special-casing. if (amount < 64) { if (amount != 0) { return MakeUint128(Uint128High64(lhs) >> amount, (Uint128Low64(lhs) >> amount) | (Uint128High64(lhs) << (64 - amount))); } return lhs; } return MakeUint128(0, Uint128High64(lhs) >> (amount - 64)); } inline uint128 operator+(uint128 lhs, uint128 rhs) { uint128 result = MakeUint128(Uint128High64(lhs) + Uint128High64(rhs), Uint128Low64(lhs) + Uint128Low64(rhs)); if (Uint128Low64(result) < Uint128Low64(lhs)) { // check for carry return MakeUint128(Uint128High64(result) + 1, Uint128Low64(result)); } return result; } inline uint128 operator-(uint128 lhs, uint128 rhs) { uint128 result = MakeUint128(Uint128High64(lhs) - Uint128High64(rhs), Uint128Low64(lhs) - Uint128Low64(rhs)); if (Uint128Low64(lhs) < Uint128Low64(rhs)) { // check for carry return MakeUint128(Uint128High64(result) - 1, Uint128Low64(result)); } return result; } inline uint128 operator*(uint128 lhs, uint128 rhs) { #if defined(ABSL_HAVE_INTRINSIC_INT128) // TODO(strel) Remove once alignment issues are resolved and unsigned __int128 // can be used for uint128 storage. return static_cast(lhs) * static_cast(rhs); #else // ABSL_HAVE_INTRINSIC128 uint64_t a32 = Uint128Low64(lhs) >> 32; uint64_t a00 = Uint128Low64(lhs) & 0xffffffff; uint64_t b32 = Uint128Low64(rhs) >> 32; uint64_t b00 = Uint128Low64(rhs) & 0xffffffff; uint128 result = MakeUint128(Uint128High64(lhs) * Uint128Low64(rhs) + Uint128Low64(lhs) * Uint128High64(rhs) + a32 * b32, a00 * b00); result += uint128(a32 * b00) << 32; result += uint128(a00 * b32) << 32; return result; #endif // ABSL_HAVE_INTRINSIC128 } // Increment/decrement operators. inline uint128 uint128::operator++(int) { uint128 tmp(*this); *this += 1; return tmp; } inline uint128 uint128::operator--(int) { uint128 tmp(*this); *this -= 1; return tmp; } inline uint128& uint128::operator++() { *this += 1; return *this; } inline uint128& uint128::operator--() { *this -= 1; return *this; } #if defined(ABSL_HAVE_INTRINSIC_INT128) #include "absl/numeric/int128_have_intrinsic.inc" #else // ABSL_HAVE_INTRINSIC_INT128 #include "absl/numeric/int128_no_intrinsic.inc" #endif // ABSL_HAVE_INTRINSIC_INT128 } // namespace absl #endif // ABSL_NUMERIC_INT128_H_