#ifndef INT64X64_128_H

#define INT64X64_128_H

#include "ns3/core-config.h"

#include <stdint.h>

#include <math.h>

#if defined(HAVE___UINT128_T) and !defined(HAVE_UINT128_T)

typedef __uint128_t uint128_t;

typedef __int128_t int128_t;

#endif

namespace ns3 {

#define HP128_MAX_64 18446744073709551615.0

#define HP128_MASK_LO ((((int128_t)1)<<64)-1)

class int64x64_t

{

public:

  inline int64x64_t ()

    : _v (0)

  {}

  inline int64x64_t (double value)

  {

    bool is_negative = value < 0;

    value = is_negative?-value:value;

    double hi = floor (value);

    double lo = (value - hi) * HP128_MAX_64;

    _v = (int128_t)hi;

    _v <<= 64;

    _v += (int128_t)lo;

    _v = is_negative?-_v:_v;

  }

  inline int64x64_t (int v)

    : _v (v)

  {

    _v <<= 64;

  }

  inline int64x64_t (long int v)

    : _v (v) 

  {

    _v <<= 64;

  }

  inline int64x64_t (long long int v)

    : _v (v) 

  {

    _v <<= 64;

  }

  inline int64x64_t (unsigned int v)

    : _v (v)

  {

    _v <<= 64;

  }

  inline int64x64_t (unsigned long int v)

    : _v (v) 

  {

    _v <<= 64;

  }

  inline int64x64_t (unsigned long long int v)

    : _v (v) 

  {

    _v <<= 64;

  }

  explicit inline int64x64_t (int64_t hi, uint64_t lo)

  {

    bool is_negative = hi<0;

    _v = is_negative?-hi:hi;

    _v <<= 64;

    _v += lo;

    _v = is_negative?-_v:_v;

  }

  inline int64x64_t (const int64x64_t &o)

    : _v (o._v) {}

  inline int64x64_t &operator = (const int64x64_t &o)

    {

      _v = o._v;

      return *this;

    }

  inline double GetDouble (void) const

  {

    bool is_negative = _v < 0;

    uint128_t value = is_negative ? -_v:_v;

    uint64_t hi = value >> 64;

    uint64_t lo = value;

    double flo = lo;

    flo /= HP128_MAX_64;

    double retval = hi;

    retval += flo;

    retval = is_negative ? -retval : retval;

    return retval;

  }

  inline int64_t GetHigh (void) const

  {

    bool negative = _v < 0;

    int128_t v = negative?-_v:_v;

    v >>= 64;

    int64_t retval = v;

    return negative?-retval:retval;

  }

  inline uint64_t GetLow (void) const

  {

    bool negative = _v < 0;

    int128_t v = negative?-_v:_v;

    int128_t low = v & HP128_MASK_LO;

    uint64_t retval = low;

    return retval;

  }

#undef HP128_MAX_64

#undef HP128_MASK_LO

  void MulByInvert (const int64x64_t &o);

  static int64x64_t Invert (uint64_t v);

private:

  friend bool operator == (const int64x64_t &lhs, const int64x64_t &rhs);

  friend bool operator != (const int64x64_t &lhs, const int64x64_t &rhs);

  friend bool operator <= (const int64x64_t &lhs, const int64x64_t &rhs);

  friend bool operator >= (const int64x64_t &lhs, const int64x64_t &rhs);

  friend bool operator < (const int64x64_t &lhs, const int64x64_t &rhs);

  friend bool operator > (const int64x64_t &lhs, const int64x64_t &rhs);

  friend int64x64_t &operator += (int64x64_t &lhs, const int64x64_t &rhs);

  friend int64x64_t &operator -= (int64x64_t &lhs, const int64x64_t &rhs);

  friend int64x64_t &operator *= (int64x64_t &lhs, const int64x64_t &rhs);

  friend int64x64_t &operator /= (int64x64_t &lhs, const int64x64_t &rhs);

  friend int64x64_t operator + (const int64x64_t &lhs, const int64x64_t &rhs);

  friend int64x64_t operator - (const int64x64_t &lhs, const int64x64_t &rhs);

  friend int64x64_t operator * (const int64x64_t &lhs, const int64x64_t &rhs);

  friend int64x64_t operator / (const int64x64_t &lhs, const int64x64_t &rhs);

  friend int64x64_t operator + (const int64x64_t &lhs);

  friend int64x64_t operator - (const int64x64_t &lhs);

  friend int64x64_t operator ! (const int64x64_t &lhs);

  void Mul (const int64x64_t &o);

  void Div (const int64x64_t &o);

  static uint128_t UmulByInvert (uint128_t a, uint128_t b);

  static uint128_t Umul (uint128_t a, uint128_t b);

  static uint128_t Divu (uint128_t a, uint128_t b);

  inline int64x64_t (int128_t v)

    : _v (v) {}

  int128_t _v;

};

inline bool operator == (const int64x64_t &lhs, const int64x64_t &rhs)

{

  return lhs._v == rhs._v;

}

inline bool operator != (const int64x64_t &lhs, const int64x64_t &rhs)

{

  return lhs._v != rhs._v;

}

inline bool operator < (const int64x64_t &lhs, const int64x64_t &rhs)

{

  return lhs._v < rhs._v;

}

inline bool operator <= (const int64x64_t &lhs, const int64x64_t &rhs)

{

  return lhs._v <= rhs._v;

}

inline bool operator >= (const int64x64_t &lhs, const int64x64_t &rhs)

{

  return lhs._v >= rhs._v;

}

inline bool operator > (const int64x64_t &lhs, const int64x64_t &rhs)

{

  return lhs._v > rhs._v;

}

inline int64x64_t &operator += (int64x64_t &lhs, const int64x64_t &rhs)

{

  lhs._v += rhs._v;

  return lhs;

}

inline int64x64_t &operator -= (int64x64_t &lhs, const int64x64_t &rhs)

{

  lhs._v -= rhs._v;

  return lhs;

}

inline int64x64_t &operator *= (int64x64_t &lhs, const int64x64_t &rhs)

{

  lhs.Mul (rhs);

  return lhs;

}

inline int64x64_t &operator /= (int64x64_t &lhs, const int64x64_t &rhs)

{

  lhs.Div (rhs);

  return lhs;

}

inline int64x64_t operator + (const int64x64_t &lhs)

{

  return lhs;

}

inline int64x64_t operator - (const int64x64_t &lhs)

{

  return int64x64_t (-lhs._v);

}

inline int64x64_t operator ! (const int64x64_t &lhs)

{

  return int64x64_t (!lhs._v);

}

} // namespace ns3

#endif /* INT64X64_128_H */