gnucash/libgnucash/engine/gnc-int128.hpp
Geert Janssens 83d14e1c1c Restructure the src directory
It is split into
- /libgnucash (for the non-gui bits)
- /gnucash (for the gui)
- /common (misc source files used by both)
- /bindings (currently only holds python bindings)

This is the first step in restructuring the code. It will need much
more fine tuning later on.
2017-08-10 18:45:00 +02:00

292 lines
10 KiB
C++

/********************************************************************
* 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;
/** @addtogroup GncInt128
* @ingroup QOF
* @{
* @brief provides a 125-bit int as a base class for GncNumeric.
*
* In order to make space for the status flags the upper leg is limited to
* 0x1fffffffffffffff. Attempting to construct a GncInt128 with a larger upper
* leg will throw a std::overflow_error.
*
* All the usual operators are provided. Only the constructors and explicit
* integer conversions throw; all other errors are indicated by the overflow and
* NaN ("Not a Number") flags. Note that performing any operation on an
* overflowed or NaN Gncint128 will yield an overflowed or NaN result, so
* calling routines need not check until the end of a chained calculation.
* GncInt128 uses implicit copy and move constructors and implicit destructor.
*/
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
};
/** @addtogroup Constructors Constructors
* Constructors are templated so that a GncInt128 can be constructed from any
* arbitrary integer type or pair of integer types.
* @note If the two parameters are of differing sign, it's taken to
* mean that the lower magnitude is *reducing* the magnitude of the
* upper, so the lower magnitude will be subracted from UINT64_MAX to
* obtain the lower limb value.
* @{
*/
/** Default constructor. Makes 0. */
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} {}
/** Double-integer constructor template.
*/
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');
/** @} */
/**
* Clear the object.
*
* Sets all member variables to zero.
* @return A reference to the object for chaining.
*/
GncInt128& zero() noexcept;
/**
* Compare function.
*
* @return -1 if the object is less than the parameter, 0 if they're
* equal, and 1 if the object is greater.
*/
int cmp (const GncInt128& b) const noexcept;
/**
* Computes the Greatest Common Divisor between the object and parameter
*
* @return A GncInt128 having the GCD.
*/
GncInt128 gcd (GncInt128 b) const noexcept;
/**
* Computes the Least Common Multiple between the object and parameter
*
* @return A GncInt128 having the LCM.
*/
GncInt128 lcm (const GncInt128& b) const noexcept;
/**
* Computes the object raised to the parameter's power
*
* @param b The power to raise this to. No point in taking a GncInt128, any
* value greater than 128 would overflow on any value other than 1.
* @return A GncInt128
*/
GncInt128 pow (unsigned int n) const noexcept;
/**
* Computes a quotient and a remainder, passed as reference parameters.
*
* 'this' is the dividend. The quotient and remainder args must be initialized
* to zero.
* @param d The divisor
* @param q The quotient; will be NaN if divisor = 0
* @param r The remainder; will be 0 if divisor = 0
*/
void div (const GncInt128& d, GncInt128& q, GncInt128& r) const noexcept;
/**
* Explicit conversion to int64_t.
*
* @return A int64_t
* @throws std::overflow_error if the object's value is > INT64_MAX or NaN.
* @throws std::underflow_error if the object's value is < INT64_MIN
*/
explicit operator int64_t() const;
/**
* Explicit conversion to uint64_t.
*
* @return A uint64_t
* @throws std::overflow_error if the object's value is > UINT64_MAX or NaN.
* @throws std::underflow_error if the object's value is < 0.
*/
explicit operator uint64_t() const;
/**
* @return true if the object value is < 0
*/
bool isNeg () const noexcept;
/**
* @return true if the object value is > INT64_MAX or < INT64_MIN
*/
bool isBig () const noexcept;
/**
* @return true if a calculation has produced a result of larger
* magnitude than can be contained in the 128 bits available.
*/
bool isOverflow () const noexcept;
/**
* @return true if an illegal calculation has occurred.
*/
bool isNan () const noexcept;
/**
* @return true if the object represents 0.
*/
bool isZero() const noexcept;
/**
* @return true if neither the overflow nor nan flags are set.
*/
bool valid() const noexcept;
/**
* @return the number of bits used to represent the value
*/
unsigned int bits() const noexcept;
/**
* Fills a supplied buffer with a representation of the number in base 10. If
* the GncInt128 is overflowed or NaN it will contain the words "Overflow" or
* "NaN" respectively.
*
* @param buf char[41], 39 digits plus sign and trailing 0.
* @return pointer to the buffer for convenience
*/
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;
/** Compute the greatest common denominator of two integers
*/
GncInt128 gcd (int64_t a, int64_t b);
/** Compute the least common multiple of two integers
*/
GncInt128 lcm (int64_t a, int64_t b);
#endif //GNCINT128_H
/** @} */