YugabyteDB (2.13.1.0-b60, 21121d69985fbf76aa6958d8f04a9bfa936293b5)

// Copyright 2004 Google Inc.

// All Rights Reserved.

//

// The following only applies to changes made to this file as part of YugaByte development.

//

// Portions Copyright (c) YugaByte, Inc.

//

// 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.

//

#ifndef BASE_INT128_H_

#define BASE_INT128_H_

#include <iosfwd>

using std::ostream;

#include "yb/gutil/integral_types.h"

struct uint128_pod;

// An unsigned 128-bit integer type. Thread-compatible.

class uint128 {

 public:

  uint128();  // Sets to 0, but don't trust on this behavior.

  uint128(uint64 top, uint64 bottom);

#ifndef SWIG

  uint128(int bottom);

  uint128(uint32 bottom);   // Top 96 bits = 0

#endif

  uint128(uint64 bottom);   // hi_ = 0

  uint128(const uint128 &val);

  uint128(const uint128_pod &val);

  void Initialize(uint64 top, uint64 bottom);

  uint128& operator=(const uint128& b);

  // Arithmetic operators.

  // TODO: division, etc.

  uint128& operator+=(const uint128& b);

  uint128& operator-=(const uint128& b);

  uint128& operator*=(const uint128& b);

  uint128 operator++(int);

  uint128 operator--(int);

  uint128& operator<<=(int);

  uint128& operator>>=(int);

  uint128& operator&=(const uint128& b);

  uint128& operator|=(const uint128& b);

  uint128& operator^=(const uint128& b);

  uint128& operator++();

  uint128& operator--();

  friend uint64 Uint128Low64(const uint128& v);

  friend uint64 Uint128High64(const uint128& v);

  // We add "std::" to avoid including all of port.h.

  friend std::ostream& operator<<(std::ostream& o, const uint128& b);

 private:

  // Little-endian memory order optimizations can benefit from

  // having lo_ first, hi_ last.

  // See util/endian/endian.h and Load128/Store128 for storing a uint128.

  uint64        lo_;

  uint64        hi_;

  // Not implemented, just declared for catching automatic type conversions.

  uint128(uint8);

  uint128(uint16);

  uint128(float v);

  uint128(double v);

};

// This is a POD form of uint128 which can be used for static variables which

// need to be operated on as uint128.

struct uint128_pod {

  // Note: The ordering of fields is different than 'class uint128' but the

  // same as its 2-arg constructor.  This enables more obvious initialization

  // of static instances, which is the primary reason for this struct in the

  // first place.  This does not seem to defeat any optimizations wrt

  // operations involving this struct.

  uint64 hi;

  uint64 lo;

};

extern const uint128_pod kuint128max;

// allow uint128 to be logged

extern std::ostream& operator<<(std::ostream& o, const uint128& b);

// Methods to access low and high pieces of 128-bit value.

// Defined externally from uint128 to facilitate conversion

// to native 128-bit types when compilers support them.

inline uint64 Uint128Low64(const uint128& v) { return v.lo_; }

inline uint64 Uint128High64(const uint128& v) { return v.hi_; }

// TODO: perhaps it would be nice to have int128, a signed 128-bit type?

// --------------------------------------------------------------------------

//                      Implementation details follow

// --------------------------------------------------------------------------

inline bool operator==(const uint128& lhs, const uint128& rhs) {

  return (Uint128Low64(lhs) == Uint128Low64(rhs) &&

          Uint128High64(lhs) == Uint128High64(rhs));

}

inline bool operator!=(const uint128& lhs, const uint128& rhs) {

  return !(lhs == rhs);

}

inline uint128& uint128::operator=(const uint128& b) {

  lo_ = b.lo_;

  hi_ = b.hi_;

  return *this;

}

inline uint128::uint128(): lo_(0), hi_(0) { }

inline uint128::uint128(uint64 top, uint64 bottom) : lo_(bottom), hi_(top) { }

inline uint128::uint128(const uint128 &v) : lo_(v.lo_), hi_(v.hi_) { }

inline uint128::uint128(const uint128_pod &v) : lo_(v.lo), hi_(v.hi) { }

inline uint128::uint128(uint64 bottom) : lo_(bottom), hi_(0) { }

#ifndef SWIG

inline uint128::uint128(uint32 bottom) : lo_(bottom), hi_(0) { }

inline uint128::uint128(int bottom) : lo_(bottom), hi_(0) {

  if (bottom < 0) {

    --hi_;

  }

}

#endif

inline void uint128::Initialize(uint64 top, uint64 bottom) {

  hi_ = top;

  lo_ = bottom;

}

// Comparison operators.

#define CMP128(op)                                                \

inline bool operator op(const uint128& lhs, const uint128& rhs) { \

  return (Uint128High64(lhs) == Uint128High64(rhs)) ?             \

      (Uint128Low64(lhs) op Uint128Low64(rhs)) :                  \

      (Uint128High64(lhs) op Uint128High64(rhs));                 \

}

Unexecuted instantiation: operator<(uint128 const&, uint128 const&)

Unexecuted instantiation: operator>(uint128 const&, uint128 const&)

Unexecuted instantiation: operator>=(uint128 const&, uint128 const&)

Unexecuted instantiation: operator<=(uint128 const&, uint128 const&)

CMP128(<)

CMP128(>)

CMP128(>=)

CMP128(<=)

#undef CMP128

// Unary operators

inline uint128 operator-(const uint128& val) {

  const uint64 hi_flip = ~Uint128High64(val);

  const uint64 lo_flip = ~Uint128Low64(val);

  const uint64 lo_add = lo_flip + 1;

  if (lo_add < lo_flip) {

    return uint128(hi_flip + 1, lo_add);

  }

  return uint128(hi_flip, lo_add);

}

inline bool operator!(const uint128& val) {

  return !Uint128High64(val) && !Uint128Low64(val);

}

// Logical operators.

inline uint128 operator~(const uint128& val) {

  return uint128(~Uint128High64(val), ~Uint128Low64(val));

}

#define LOGIC128(op)                                                 \

inline uint128 operator op(const uint128& lhs, const uint128& rhs) { \

  return uint128(Uint128High64(lhs) op Uint128High64(rhs),           \

                 Uint128Low64(lhs) op Uint128Low64(rhs));            \

}

Unexecuted instantiation: operator|(uint128 const&, uint128 const&)

Unexecuted instantiation: operator&(uint128 const&, uint128 const&)

Unexecuted instantiation: operator^(uint128 const&, uint128 const&)

LOGIC128(|)

LOGIC128(&)

LOGIC128(^)

#undef LOGIC128

#define LOGICASSIGN128(op)                                   \

inline uint128& uint128::operator op(const uint128& other) { \

  hi_ op other.hi_;                                          \

  lo_ op other.lo_;                                          \

  return *this;                                              \

}

Unexecuted instantiation: uint128::operator|=(uint128 const&)

Unexecuted instantiation: uint128::operator&=(uint128 const&)

Unexecuted instantiation: uint128::operator^=(uint128 const&)

LOGICASSIGN128(|=)

LOGICASSIGN128(&=)

LOGICASSIGN128(^=)

#undef LOGICASSIGN128

// Shift operators.

inline uint128 operator<<(const uint128& val, int amount) {

  // uint64 shifts of >= 64 are undefined, so we will need some special-casing.

  if (amount < 64) {

    if (amount == 0) {

      return val;

    }

    uint64 new_hi = (Uint128High64(val) << amount) |

                    (Uint128Low64(val) >> (64 - amount));

    uint64 new_lo = Uint128Low64(val) << amount;

    return uint128(new_hi, new_lo);

  } else if (amount < 128) {

    return uint128(Uint128Low64(val) << (amount - 64), 0);

  } else {

    return uint128(0, 0);

  }

}

inline uint128 operator>>(const uint128& val, int amount) {

  // uint64 shifts of >= 64 are undefined, so we will need some special-casing.

  if (amount < 64) {

    if (amount == 0) {

      return val;

    }

    uint64 new_hi = Uint128High64(val) >> amount;

    uint64 new_lo = (Uint128Low64(val) >> amount) |

                    (Uint128High64(val) << (64 - amount));

    return uint128(new_hi, new_lo);

  } else if (amount < 128) {

    return uint128(0, Uint128High64(val) >> (amount - 64));

  } else {

    return uint128(0, 0);

  }

}

inline uint128& uint128::operator<<=(int amount) {

  // uint64 shifts of >= 64 are undefined, so we will need some special-casing.

  if (amount < 64) {

    if (amount != 0) {

      hi_ = (hi_ << amount) | (lo_ >> (64 - amount));

      lo_ = lo_ << amount;

    }

  } else if (amount < 128) {

    hi_ = lo_ << (amount - 64);

    lo_ = 0;

  } else {

    hi_ = 0;

    lo_ = 0;

  }

  return *this;

}

inline uint128& uint128::operator>>=(int amount) {

  // uint64 shifts of >= 64 are undefined, so we will need some special-casing.

  if (amount < 64) {

    if (amount != 0) {

      lo_ = (lo_ >> amount) | (hi_ << (64 - amount));

      hi_ = hi_ >> amount;

    }

  } else if (amount < 128) {

    hi_ = 0;

    lo_ = hi_ >> (amount - 64);

  } else {

    hi_ = 0;

    lo_ = 0;

  }

  return *this;

}

inline uint128 operator+(const uint128& lhs, const uint128& rhs) {

  return uint128(lhs) += rhs;

}

inline uint128 operator-(const uint128& lhs, const uint128& rhs) {

  return uint128(lhs) -= rhs;

}

inline uint128 operator*(const uint128& lhs, const uint128& rhs) {

  return uint128(lhs) *= rhs;

}

inline uint128& uint128::operator+=(const uint128& b) {

  hi_ += b.hi_;

  uint64 lolo = lo_ + b.lo_;

  if (lolo < lo_)

    ++hi_;

  lo_ = lolo;

  return *this;

}

inline uint128& uint128::operator-=(const uint128& b) {

  hi_ -= b.hi_;

  if (b.lo_ > lo_)

    --hi_;

  lo_ -= b.lo_;

  return *this;

}

inline uint128& uint128::operator*=(const uint128& b) {

  uint64 a96 = hi_ >> 32;

  uint64 a64 = hi_ & 0xffffffffu;

  uint64 a32 = lo_ >> 32;

  uint64 a00 = lo_ & 0xffffffffu;

  uint64 b96 = b.hi_ >> 32;

  uint64 b64 = b.hi_ & 0xffffffffu;

  uint64 b32 = b.lo_ >> 32;

  uint64 b00 = b.lo_ & 0xffffffffu;

  // multiply [a96 .. a00] x [b96 .. b00]

  // terms higher than c96 disappear off the high side

  // terms c96 and c64 are safe to ignore carry bit

  uint64 c96 = a96 * b00 + a64 * b32 + a32 * b64 + a00 * b96;

  uint64 c64 = a64 * b00 + a32 * b32 + a00 * b64;

  this->hi_ = (c96 << 32) + c64;

  this->lo_ = 0;

  // add terms after this one at a time to capture carry

  *this += uint128(a32 * b00) << 32;

  *this += uint128(a00 * b32) << 32;

  *this += a00 * b00;

  return *this;

}

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;

}

#endif  // BASE_INT128_H_