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1 | /* -*-c-*- |
2 | * |
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3 | * $Id: mptext-string.c,v 1.4 2004/04/01 12:50:09 mdw Exp $ |
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4 | * |
5 | * Reading and writing large integers on strings |
6 | * |
7 | * (c) 1999 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: mptext-string.c,v $ |
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33 | * Revision 1.4 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 | * |
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40 | * Revision 1.3 2000/08/04 23:23:44 mdw |
41 | * Various <ctype.h> fixes. |
42 | * |
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43 | * Revision 1.2 1999/12/22 15:56:21 mdw |
44 | * Make the buffer passed to `put' op constant. |
45 | * |
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46 | * Revision 1.1 1999/11/17 18:02:16 mdw |
47 | * New multiprecision integer arithmetic suite. |
48 | * |
49 | */ |
50 | |
51 | /*----- Header files ------------------------------------------------------*/ |
52 | |
53 | #include <string.h> |
54 | |
55 | #include "mptext.h" |
56 | |
57 | /*----- Main code ---------------------------------------------------------*/ |
58 | |
59 | /* --- Operations table --- */ |
60 | |
61 | static int get(void *p) |
62 | { |
63 | mptext_stringctx *c = p; |
64 | if (c->buf >= c->lim) |
65 | return (EOF); |
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66 | return ((unsigned char)*c->buf++); |
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67 | } |
68 | |
69 | static void unget(int ch, void *p) |
70 | { |
71 | mptext_stringctx *c = p; |
72 | if (ch != EOF) |
73 | c->buf--; |
74 | } |
75 | |
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76 | static int put(const char *s, size_t sz, void *p) |
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77 | { |
78 | mptext_stringctx *c = p; |
79 | int rc = 0; |
80 | if (sz > c->lim - c->buf) { |
81 | sz = c->lim - c->buf; |
82 | rc = EOF; |
83 | } |
84 | if (sz) { |
85 | memcpy(c->buf, s, sz); |
86 | c->buf += sz; |
87 | } |
88 | return (rc); |
89 | } |
90 | |
91 | const mptext_ops mptext_stringops = { get, unget, put }; |
92 | |
93 | /* --- Convenience functions --- */ |
94 | |
95 | mp *mp_readstring(mp *m, const char *p, char **end, int radix) |
96 | { |
97 | mptext_stringctx c; |
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98 | c.buf = (/*unconst */ char *)p; |
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99 | c.lim = c.buf + strlen(p); |
100 | m = mp_read(m, radix, &mptext_stringops, &c); |
101 | if (end) |
102 | *end = c.buf; |
103 | return (m); |
104 | } |
105 | |
106 | int mp_writestring(mp *m, char *p, size_t sz, int radix) |
107 | { |
108 | mptext_stringctx c; |
109 | int rc; |
110 | if (!sz) |
111 | return (0); |
112 | c.buf = p; |
113 | c.lim = p + sz - 1; |
114 | rc = mp_write(m, radix, &mptext_stringops, &c); |
115 | *c.buf = 0; |
116 | return (rc); |
117 | } |
118 | |
119 | /*----- That's all, folks -------------------------------------------------*/ |