contrib/gmp/mpq/set_si.c

   1 /* mpq_set_si(dest,ulong_num,ulong_den) -- Set DEST to the rational number
   2    ULONG_NUM/ULONG_DEN.
   3
   4 Copyright 1991, 1994, 1995, 2001, 2003 Free Software Foundation, Inc.
   5
   6 This file is part of the GNU MP Library.
   7
   8 The GNU MP Library is free software; you can redistribute it and/or modify
   9 it under the terms of the GNU Lesser General Public License as published by
  10 the Free Software Foundation; either version 3 of the License, or (at your
  11 option) any later version.
  12
  13 The GNU MP Library is distributed in the hope that it will be useful, but
  14 WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
  15 or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public
  16 License for more details.
  17
  18 You should have received a copy of the GNU Lesser General Public License
  19 along with the GNU MP Library.  If not, see http://www.gnu.org/licenses/.  */
  20
  21 #include "gmp.h"
  22 #include "gmp-impl.h"
  23
  24 void
  25 mpq_set_si (MP_RAT *dest, signed long int num, unsigned long int den)
  26 {
  27   unsigned long int abs_num;
  28
  29   if (GMP_NUMB_BITS < BITS_PER_ULONG)
  30     {
  31       if (num == 0)  /* Canonicalize 0/d to 0/1.  */
  32         den = 1;
  33       mpz_set_si (mpq_numref (dest), num);
  34       mpz_set_ui (mpq_denref (dest), den);
  35       return;
  36     }
  37
  38   abs_num = ABS_CAST (unsigned long, num);
  39
  40   if (num == 0)
  41     {
  42       /* Canonicalize 0/d to 0/1.  */
  43       den = 1;
  44       dest->_mp_num._mp_size = 0;
  45     }
  46   else
  47     {
  48       dest->_mp_num._mp_d[0] = abs_num;
  49       dest->_mp_num._mp_size = num > 0 ? 1 : -1;
  50     }
  51
  52   dest->_mp_den._mp_d[0] = den;
  53   dest->_mp_den._mp_size = (den != 0);
  54 }