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1 | /* -*-c-*- |
2 | * |
3 | * $Id: group-string.c,v 1.1 2004/04/01 12:50:09 mdw Exp $ |
4 | * |
5 | * String I/O for group elements |
6 | * |
7 | * (c) 2004 Straylight/Edgeware |
8 | */ |
9 | |
10 | /*----- Licensing notice --------------------------------------------------* |
11 | * |
12 | * This file is part of Catacomb. |
13 | * |
14 | * Catacomb is free software; you can redistribute it and/or modify |
15 | * it under the terms of the GNU Library General Public License as |
16 | * published by the Free Software Foundation; either version 2 of the |
17 | * License, or (at your option) any later version. |
18 | * |
19 | * Catacomb is distributed in the hope that it will be useful, |
20 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
21 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
22 | * GNU Library General Public License for more details. |
23 | * |
24 | * You should have received a copy of the GNU Library General Public |
25 | * License along with Catacomb; if not, write to the Free |
26 | * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, |
27 | * MA 02111-1307, USA. |
28 | */ |
29 | |
30 | /*----- Revision history --------------------------------------------------* |
31 | * |
32 | * $Log: group-string.c,v $ |
33 | * Revision 1.1 2004/04/01 12:50:09 mdw |
34 | * Add cyclic group abstraction, with test code. Separate off exponentation |
35 | * functions for better static linking. Fix a buttload of bugs on the way. |
36 | * Generally ensure that negative exponents do inversion correctly. Add |
37 | * table of standard prime-field subgroups. (Binary field subgroups are |
38 | * currently unimplemented but easy to add if anyone ever finds a good one.) |
39 | * |
40 | */ |
41 | |
42 | /*----- Header files ------------------------------------------------------*/ |
43 | |
44 | #include "group.h" |
45 | |
46 | /*----- Main code ---------------------------------------------------------*/ |
47 | |
48 | /* --- @group_readstring@ --- * |
49 | * |
50 | * Arguments: @group *g@ = an abstract group |
51 | * @ge *d@ = destination group element |
52 | * @const char *p@ = where the string is |
53 | * @char **end@ = where to put the end pointer |
54 | * |
55 | * Returns: Zero on success, nonzero on failure. |
56 | * |
57 | * Use: Parses a group element from a string. |
58 | */ |
59 | |
60 | int group_readstring(group *g, ge *d, const char *p, char **end) |
61 | { |
62 | mptext_stringctx ms; |
63 | |
64 | ms.buf = (/*unconst*/ char *)p; |
65 | ms.lim = (/*unconst*/ char *)p + strlen(p); |
66 | if (G_READ(g, d, &mptext_stringops, &ms)) |
67 | return (-1); |
68 | if (end) *end = ms.buf; |
69 | return (0); |
70 | } |
71 | |
72 | /* --- @group_writestring@ --- * |
73 | * |
74 | * Arguments: @group *g@ = an abstract group |
75 | * @ge *x@ = a group element |
76 | * @char *p@ = where the string should go |
77 | * @size_t sz@ = how long the buffer is |
78 | * |
79 | * Returns: Zero on success, nonzero on failure. |
80 | * |
81 | * Use: Writes a group element to a string buffer. |
82 | */ |
83 | |
84 | int group_writestring(group *g, ge *x, char *p, size_t sz) |
85 | { |
86 | mptext_stringctx ms; |
87 | |
88 | ms.buf = p; |
89 | ms.lim = p + sz - 1; |
90 | if (G_WRITE(g, x, &mptext_stringops, &ms)) |
91 | return (-1); |
92 | *ms.buf = 0; |
93 | return (0); |
94 | } |
95 | |
96 | /*----- That's all, folks -------------------------------------------------*/ |