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
23int 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}
46EXPORT_SYMBOL_GPL(mpi_cmp_ui);
47
48static int do_mpi_cmp(MPI u, MPI v, int absmode)
49{
50	mpi_size_t usize;
51	mpi_size_t vsize;
52	int usign;
53	int vsign;
54	int cmp;
55
56	mpi_normalize(u);
57	mpi_normalize(v);
58
59	usize = u->nlimbs;
60	vsize = v->nlimbs;
61	usign = absmode ? 0 : u->sign;
62	vsign = absmode ? 0 : v->sign;
63
64	/* Compare sign bits.  */
65
66	if (!usign && vsign)
67		return 1;
68	if (usign && !vsign)
69		return -1;
70
71	/* U and V are either both positive or both negative.  */
72
73	if (usize != vsize && !usign && !vsign)
74		return usize - vsize;
75	if (usize != vsize && usign && vsign)
76		return vsize + usize;
77	if (!usize)
78		return 0;
79	cmp = mpihelp_cmp(u->d, v->d, usize);
80	if (!cmp)
81		return 0;
82	if ((cmp < 0?1:0) == (usign?1:0))
83		return 1;
84
85	return -1;
86}
87
88int mpi_cmp(MPI u, MPI v)
89{
90	return do_mpi_cmp(u, v, 0);
91}
92EXPORT_SYMBOL_GPL(mpi_cmp);
93
94int mpi_cmpabs(MPI u, MPI v)
95{
96	return do_mpi_cmp(u, v, 1);
97}
98EXPORT_SYMBOL_GPL(mpi_cmpabs);
99