gnc-int128.hpp

/********************************************************************
 * qofmath128.h -- an 128-bit integer library                       *
 * Copyright (C) 2004 Linas Vepstas <linas@linas.org>               *
 * Copyright (C) 2014 John Ralls <jralls@ceridwen.us>               *
 *                                                                  *
 * This program is free software; you can redistribute it and/or    *
 * modify it under the terms of the GNU General Public License as   *
 * published by the Free Software Foundation; either version 2 of   *
 * the License, or (at your option) any later version.              *
 *                                                                  *
 * This program is distributed in the hope that it will be useful,  *
 * but WITHOUT ANY WARRANTY; without even the implied warranty of   *
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the    *
 * GNU General Public License for more details.                     *
 *                                                                  *
 * You should have received a copy of the GNU General Public License*
 * along with this program; if not, contact:                        *
 *                                                                  *
 * Free Software Foundation           Voice:  +1-617-542-5942       *
 * 51 Franklin Street, Fifth Floor    Fax:    +1-617-542-2652       *
 * Boston, MA  02110-1301,  USA       gnu@gnu.org                   *
 *                                                                  *
 *******************************************************************/

#ifndef GNCINT128_H
#define GNCINT128_H

extern "C"
{
#ifndef __STDC_LIMIT_MACROS
#define  __STDC_LIMIT_MACROS 1
#endif
#ifndef __STDC_CONSTANT_MACROS
#define  __STDC_CONSTANT_MACROS 1
#endif
#ifndef __STDC_FORMAT_MACROS
#define  __STDC_FORMAT_MACROS 1
#endif
#include <inttypes.h>
}

#include <stdexcept>
#include <string>
#include <ostream>
#include <type_traits>

//using std::string;
class GncInt128
{
    uint64_t m_hi;
    uint64_t m_lo;

public:
    static const unsigned int flagbits = 3;
    static const unsigned int numlegs = 2;
    static const unsigned int legbits = 64;
    static const unsigned int maxbits = legbits * numlegs - flagbits;

enum // Values for m_flags
{
    pos = 0,
    neg = 1,
    overflow = 2,
    NaN = 4
};
    GncInt128();
    template <typename T>
    GncInt128(T lower) : GncInt128(INT64_C(0), static_cast<int64_t>(lower))
    {
        static_assert (std::is_integral<T>(),
                       "GncInt128 can be constructed only with "
                       "integral arguments.");
    }
    GncInt128(uint64_t lower) : GncInt128 {UINT64_C(0), lower} {}
    template <typename T, typename U>
    GncInt128(T upper, U lower, unsigned char flags = '\0') :
        GncInt128 {static_cast<int64_t>(upper),
                   static_cast<int64_t>(lower), flags}
    {
        static_assert (std::is_integral<T>(),
                       "GncInt128 can be constructed only with "
                       "integral arguments.");
        static_assert (std::is_integral<U>(),
                       "GncInt128 can be constructed only with "
                       "integral arguments.");
    }

    GncInt128 (int64_t upper, int64_t lower, unsigned char flags = '\0');
    template <typename T>
    GncInt128(T upper, uint64_t lower) :
        GncInt128 {static_cast<int64_t>(upper), lower}
        {
            static_assert (std::is_integral<T>(),
                           "GncInt128 can be constructed only with "
                           "integral arguments.");
        }

    GncInt128 (int64_t upper, uint64_t lower, unsigned char flags = '\0');
    GncInt128 (uint64_t upper, uint64_t lower, unsigned char flags = '\0');
    GncInt128& zero() noexcept;

    int cmp (const GncInt128& b) const noexcept;

    GncInt128 gcd (GncInt128 b) const noexcept;
    GncInt128 lcm (const GncInt128& b) const noexcept;

    GncInt128 pow (unsigned int n) const noexcept;

    void div (const GncInt128& d, GncInt128& q, GncInt128& r) const noexcept;

    explicit operator int64_t() const;
    explicit operator uint64_t() const;

    bool isNeg () const noexcept;
    bool isBig () const noexcept;
    bool isOverflow () const noexcept;
    bool isNan () const noexcept;
    bool isZero() const noexcept;
    bool valid() const noexcept;

    unsigned int bits() const noexcept;

    char* asCharBufR(char* buf) const noexcept;

    GncInt128 abs() const noexcept;

    GncInt128 operator-() const noexcept;
    explicit operator bool() const noexcept;

    GncInt128& operator++ () noexcept;
    GncInt128& operator++ (int) noexcept;
    GncInt128& operator-- () noexcept;
    GncInt128& operator-- (int) noexcept;
    GncInt128& operator<<= (unsigned int i) noexcept;
    GncInt128& operator>>= (unsigned int i) noexcept;
    GncInt128& operator+= (const GncInt128& b) noexcept;
    GncInt128& operator-= (const GncInt128& b) noexcept;
    GncInt128& operator*= (const GncInt128& b) noexcept;
    GncInt128& operator/= (const GncInt128& b) noexcept;
    GncInt128& operator%= (const GncInt128& b) noexcept;
    GncInt128& operator&= (const GncInt128& b) noexcept;
    GncInt128& operator|= (const GncInt128& b) noexcept;
    GncInt128& operator^= (const GncInt128& b) noexcept;

};

static const GncInt128 k_gncint128_Max {UINT64_MAX, UINT64_MAX, GncInt128::pos};
static const GncInt128 k_gncint128_Min {UINT64_MAX, UINT64_MAX, GncInt128::neg};

GncInt128 operator+ (GncInt128 a, const GncInt128& b) noexcept;
GncInt128 operator- (GncInt128 a, const GncInt128& b) noexcept;
GncInt128 operator* (GncInt128 a, const GncInt128& b) noexcept;
GncInt128 operator/ (GncInt128 a, const GncInt128& b) noexcept;
GncInt128 operator% (GncInt128 a, const GncInt128& b) noexcept;
GncInt128 operator& (GncInt128 a, const GncInt128& b) noexcept;
GncInt128 operator| (GncInt128 a, const GncInt128& b) noexcept;
GncInt128 operator^ (GncInt128 a, const GncInt128& b) noexcept;
GncInt128 operator<< (GncInt128 a, unsigned int b) noexcept;
GncInt128 operator>> (GncInt128 a, unsigned int b) noexcept;

bool operator== (const GncInt128& a, const GncInt128& b) noexcept;
bool operator!= (const GncInt128& a, const GncInt128& b) noexcept;
bool operator<= (const GncInt128& a, const GncInt128& b) noexcept;
bool operator>= (const GncInt128& a, const GncInt128& b) noexcept;
bool operator< (const GncInt128& a, const GncInt128& b) noexcept;
bool operator> (const GncInt128& a, const GncInt128& b) noexcept;

std::ostream& operator<< (std::ostream&, const GncInt128&) noexcept;

GncInt128 gcd (int64_t a, int64_t b);

GncInt128 lcm (int64_t a, int64_t b);

#endif //GNCINT128_H