contrib/gmp/mpq/cmp_si.c

   1 /* _mpq_cmp_si -- compare mpq and long/ulong fraction.
   2
   3 Copyright 2001 Free Software Foundation, Inc.
   4
   5 This file is part of the GNU MP Library.
   6
   7 The GNU MP Library is free software; you can redistribute it and/or modify
   8 it under the terms of the GNU Lesser General Public License as published by
   9 the Free Software Foundation; either version 3 of the License, or (at your
  10 option) any later version.
  11
  12 The GNU MP Library is distributed in the hope that it will be useful, but
  13 WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
  14 or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public
  15 License for more details.
  16
  17 You should have received a copy of the GNU Lesser General Public License
  18 along with the GNU MP Library.  If not, see http://www.gnu.org/licenses/.  */
  19
  20 #include "gmp.h"
  21 #include "gmp-impl.h"
  22
  23
  24 /* Something like mpq_cmpabs_ui would be more useful for the neg/neg case,
  25    and perhaps a version accepting a parameter to reverse the test, to make
  26    it a tail call here.  */
  27
  28 int
  29 _mpq_cmp_si (mpq_srcptr q, long n, unsigned long d)
  30 {
  31   /* need canonical sign to get right result */
  32   ASSERT (q->_mp_den._mp_size > 0);
  33
  34   if (q->_mp_num._mp_size >= 0)
  35     {
  36       if (n >= 0)
  37         return _mpq_cmp_ui (q, n, d);            /* >=0 cmp >=0 */
  38       else
  39         return 1;                                /* >=0 cmp <0 */
  40     }
  41   else
  42     {
  43       if (n >= 0)
  44         return -1;                               /* <0 cmp >=0 */
  45       else
  46         {
  47           mpq_t  qabs;
  48           qabs->_mp_num._mp_size = ABS (q->_mp_num._mp_size);
  49           qabs->_mp_num._mp_d    = q->_mp_num._mp_d;
  50           qabs->_mp_den._mp_size = q->_mp_den._mp_size;
  51           qabs->_mp_den._mp_d    = q->_mp_den._mp_d;
  52
  53           return - _mpq_cmp_ui (qabs, -n, d);    /* <0 cmp <0 */
  54         }
  55     }
  56 }