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1 | /* -*-c-*- |
2 | * |
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3 | * $Id: tx.c,v 1.2 1997/08/04 10:24:25 mdw Exp $ |
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4 | * |
5 | * Transfer for keys and other large integers |
6 | * |
7 | * (c) 1997 Mark Wooding |
8 | */ |
9 | |
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10 | /*----- Licensing notice --------------------------------------------------* |
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11 | * |
12 | * This file is part of `become' |
13 | * |
14 | * `Become' is free software; you can redistribute it and/or modify |
15 | * it under the terms of the GNU General Public License as published by |
16 | * the Free Software Foundation; either version 2 of the License, or |
17 | * (at your option) any later version. |
18 | * |
19 | * `Become' 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 General Public License for more details. |
23 | * |
24 | * You should have received a copy of the GNU General Public License |
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25 | * along with `become'; if not, write to the Free Software Foundation, |
26 | * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. |
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27 | */ |
28 | |
29 | /*----- Revision history --------------------------------------------------* |
30 | * |
31 | * $Log: tx.c,v $ |
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32 | * Revision 1.2 1997/08/04 10:24:25 mdw |
33 | * Sources placed under CVS control. |
34 | * |
35 | * Revision 1.1 1997/07/21 13:47:43 mdw |
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36 | * Initial revision |
37 | * |
38 | */ |
39 | |
40 | /*----- Header files ------------------------------------------------------*/ |
41 | |
42 | /* --- ANSI headers --- */ |
43 | |
44 | #include <errno.h> |
45 | #include <stdio.h> |
46 | #include <stdlib.h> |
47 | #include <string.h> |
48 | |
49 | /* --- Local headers --- */ |
50 | |
51 | #include "config.h" |
52 | #include "tx.h" |
53 | |
54 | /*----- Main code ---------------------------------------------------------*/ |
55 | |
56 | /* --- @tx_getBits@ --- * |
57 | * |
58 | * Arguments: @unsigned char *k@ = pointer to key array to unpack into |
59 | * @size_t sz@ = number of bits to read (elements in array) |
60 | * @FILE *fp@ = stream to read from |
61 | * |
62 | * Returns: --- |
63 | * |
64 | * Use: Reads a number of bits into an array. The least significant |
65 | * bits of the final word are cleared to zero. |
66 | */ |
67 | |
68 | void tx_getBits(unsigned char *k, size_t sz, FILE *fp) |
69 | { |
70 | int i = 0; |
71 | unsigned char a = 0; |
72 | unsigned int ch; |
73 | size_t wsz = (size_t)((sz + 7ul) & ~7ul); |
74 | int t; |
75 | |
76 | while ((t = getc(fp)) != EOF) { |
77 | |
78 | /* --- Allow separators for readbility --- */ |
79 | |
80 | if (t == '-') |
81 | continue; |
82 | |
83 | /* --- Standard converting-from-hex-digit code --- * |
84 | * |
85 | * Assumes that 'a'--'f' and 'A'--'F' are contiguous and in order, in |
86 | * addition to the guarantee that '0'--'9' are like this. The assumption |
87 | * is true in ASCII (and character sets based thereon) and EBCDIC. |
88 | */ |
89 | |
90 | ch = (unsigned)t; |
91 | ch -= '0'; |
92 | if (ch > 9) ch -= 'A' - '0' - 10; |
93 | if (ch > 15) ch -= 'a' - 'A'; |
94 | if (ch > 15) break; |
95 | |
96 | /* --- Accumulate and maybe store --- */ |
97 | |
98 | a = (a << 4) | ch; |
99 | i++; |
100 | sz -= 4, wsz -= 4; |
101 | if ((i & 1) == 0) |
102 | *k++ = a, a = 0; |
103 | if (!sz) |
104 | break; |
105 | } |
106 | |
107 | /* --- Pad the rest out with zeros --- */ |
108 | |
109 | while (wsz) { |
110 | a <<= 4; |
111 | i++; |
112 | wsz -= 4; |
113 | if ((i & 1) == 0) |
114 | *k++ = a, a = 0; |
115 | } |
116 | } |
117 | |
118 | /* --- @tx_putBits@ --- * |
119 | * |
120 | * Arguments: @unsigned char *k@ = pointer to key block |
121 | * @size_t sz@ = number of bits to write |
122 | * @FILE *fp@ = pointer to stream to write on |
123 | * |
124 | * Returns: --- |
125 | * |
126 | * Use: Complements @tx_getBits@ above. Writes a number of bits |
127 | * to a file in an easy-to-read and transportable format (hex!) |
128 | */ |
129 | |
130 | void tx_putBits(unsigned char *k, size_t sz, FILE *fp) |
131 | { |
132 | const static char hex[16] = "0123456789abcdef"; |
133 | size_t dash; |
134 | size_t d; |
135 | unsigned char i; |
136 | |
137 | /* --- Don't do anything unless we have to --- */ |
138 | |
139 | if (!sz) |
140 | return; |
141 | |
142 | /* --- Now decide where to `dash' the output --- */ |
143 | |
144 | if (sz % 32 == 0) |
145 | dash = 4; |
146 | else if (sz % 40 == 0) |
147 | dash = 5; |
148 | else |
149 | dash = 0; |
150 | |
151 | /* --- Start writing values out --- */ |
152 | |
153 | d = dash; |
154 | |
155 | for (;;) { |
156 | |
157 | /* --- Write next byte out --- */ |
158 | |
159 | i = *k++; |
160 | putc(hex[(i >> 4) & 0x0fu], fp); |
161 | putc(hex[(i >> 0) & 0x0fu], fp); |
162 | |
163 | /* --- If done, stop now --- */ |
164 | |
165 | if (sz -= 8, sz == 0) |
166 | break; |
167 | |
168 | /* --- If need a dash, print one --- */ |
169 | |
170 | if (!--d) { |
171 | putc('-', fp); |
172 | d = dash; |
173 | } |
174 | } |
175 | |
176 | /* --- Print the final newline --- */ |
177 | |
178 | fputc('\n', fp); |
179 | } |
180 | |
181 | /*----- That's all, folks -------------------------------------------------*/ |