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12f008b6 DH |
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 | EXPORT_SYMBOL_GPL(mpi_cmp_ui); | |
43 | ||
a8ea8bdd | 44 | static int do_mpi_cmp(MPI u, MPI v, int absmode) |
12f008b6 | 45 | { |
a8ea8bdd TZ |
46 | mpi_size_t usize; |
47 | mpi_size_t vsize; | |
48 | int usign; | |
49 | int vsign; | |
12f008b6 DH |
50 | int cmp; |
51 | ||
52 | mpi_normalize(u); | |
53 | mpi_normalize(v); | |
a8ea8bdd | 54 | |
12f008b6 DH |
55 | usize = u->nlimbs; |
56 | vsize = v->nlimbs; | |
a8ea8bdd TZ |
57 | usign = absmode ? 0 : u->sign; |
58 | vsign = absmode ? 0 : v->sign; | |
59 | ||
60 | /* Compare sign bits. */ | |
61 | ||
62 | if (!usign && vsign) | |
12f008b6 | 63 | return 1; |
a8ea8bdd | 64 | if (usign && !vsign) |
12f008b6 | 65 | return -1; |
a8ea8bdd TZ |
66 | |
67 | /* U and V are either both positive or both negative. */ | |
68 | ||
69 | if (usize != vsize && !usign && !vsign) | |
12f008b6 | 70 | return usize - vsize; |
a8ea8bdd TZ |
71 | if (usize != vsize && usign && vsign) |
72 | return vsize + usize; | |
12f008b6 DH |
73 | if (!usize) |
74 | return 0; | |
75 | cmp = mpihelp_cmp(u->d, v->d, usize); | |
a8ea8bdd TZ |
76 | if (!cmp) |
77 | return 0; | |
78 | if ((cmp < 0?1:0) == (usign?1:0)) | |
79 | return 1; | |
80 | ||
81 | return -1; | |
82 | } | |
83 | ||
84 | int mpi_cmp(MPI u, MPI v) | |
85 | { | |
86 | return do_mpi_cmp(u, v, 0); | |
12f008b6 DH |
87 | } |
88 | EXPORT_SYMBOL_GPL(mpi_cmp); | |
a8ea8bdd TZ |
89 | |
90 | int mpi_cmpabs(MPI u, MPI v) | |
91 | { | |
92 | return do_mpi_cmp(u, v, 1); | |
93 | } | |
94 | EXPORT_SYMBOL_GPL(mpi_cmpabs); |