xref: /linux/lib/crypto/mpi/mpi-cmp.c (revision 55d0969c451159cff86949b38c39171cab962069)
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 == 0) {
29 		if (v == 0)
30 			return 0;
31 		else
32 			return -1;
33 	}
34 	if (u->sign)
35 		return -1;
36 	if (u->nlimbs > 1)
37 		return 1;
38 
39 	if (u->d[0] == limb)
40 		return 0;
41 	else if (u->d[0] > limb)
42 		return 1;
43 	else
44 		return -1;
45 }
46 EXPORT_SYMBOL_GPL(mpi_cmp_ui);
47 
48 int mpi_cmp(MPI u, MPI v)
49 {
50 	mpi_size_t usize, vsize;
51 	int cmp;
52 
53 	mpi_normalize(u);
54 	mpi_normalize(v);
55 	usize = u->nlimbs;
56 	vsize = v->nlimbs;
57 	if (!u->sign && v->sign)
58 		return 1;
59 	if (u->sign && !v->sign)
60 		return -1;
61 	if (usize != vsize && !u->sign && !v->sign)
62 		return usize - vsize;
63 	if (usize != vsize && u->sign && v->sign)
64 		return vsize - usize;
65 	if (!usize)
66 		return 0;
67 	cmp = mpihelp_cmp(u->d, v->d, usize);
68 	if (u->sign)
69 		return -cmp;
70 	return cmp;
71 }
72 EXPORT_SYMBOL_GPL(mpi_cmp);
73