lib/mpi/mpi-cmp.c

   1 /* mpi-cmp.c  -  MPI functions
   2  * Copyright (C) 1998, 1999 Free Software Foundation, Inc.
   3  *
   4  * This file is part of GnuPG.
   5  *
   6  * GnuPG is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; either version 2 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * GnuPG is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program; if not, write to the Free Software
  18  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
  19  */
  20
  21 #include "mpi-internal.h"
  22
  23 int mpi_cmp_ui(MPI u, unsigned long v)
  24 {
  25         mpi_limb_t limb = v;
  26
  27         mpi_normalize(u);
  28         if (!u->nlimbs && !limb)
  29                 return 0;
  30         if (u->sign)
  31                 return -1;
  32         if (u->nlimbs > 1)
  33                 return 1;
  34
  35         if (u->d[0] == limb)
  36                 return 0;
  37         else if (u->d[0] > limb)
  38                 return 1;
  39         else
  40                 return -1;
  41 }
  42
  43 int mpi_cmp(MPI u, MPI v)
  44 {
  45         mpi_size_t usize, vsize;
  46         int cmp;
  47
  48         mpi_normalize(u);
  49         mpi_normalize(v);
  50         usize = u->nlimbs;
  51         vsize = v->nlimbs;
  52         if (!u->sign && v->sign)
  53                 return 1;
  54         if (u->sign && !v->sign)
  55                 return -1;
  56         if (usize != vsize && !u->sign && !v->sign)
  57                 return usize - vsize;
  58         if (usize != vsize && u->sign && v->sign)
  59                 return vsize + usize;
  60         if (!usize)
  61                 return 0;
  62         cmp = mpihelp_cmp(u->d, v->d, usize);
  63         if (!cmp)
  64                 return 0;
  65         if ((cmp < 0 ? 1 : 0) == (u->sign ? 1 : 0))
  66                 return 1;
  67         return -1;
  68 }