c4f2d992 |
1 | /* -*-c-*- |
2 | * |
3 | * $Id: tx.c,v 1.1 1997/07/21 13:47:43 mdw Exp $ |
4 | * |
5 | * Transfer for keys and other large integers |
6 | * |
7 | * (c) 1997 Mark Wooding |
8 | */ |
9 | |
10 | /*----- Licencing notice --------------------------------------------------* |
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 |
25 | * along with `become'; if not, write to the Free Software |
26 | * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. |
27 | */ |
28 | |
29 | /*----- Revision history --------------------------------------------------* |
30 | * |
31 | * $Log: tx.c,v $ |
32 | * Revision 1.1 1997/07/21 13:47:43 mdw |
33 | * Initial revision |
34 | * |
35 | */ |
36 | |
37 | /*----- Header files ------------------------------------------------------*/ |
38 | |
39 | /* --- ANSI headers --- */ |
40 | |
41 | #include <errno.h> |
42 | #include <stdio.h> |
43 | #include <stdlib.h> |
44 | #include <string.h> |
45 | |
46 | /* --- Local headers --- */ |
47 | |
48 | #include "config.h" |
49 | #include "tx.h" |
50 | |
51 | /*----- Main code ---------------------------------------------------------*/ |
52 | |
53 | /* --- @tx_getBits@ --- * |
54 | * |
55 | * Arguments: @unsigned char *k@ = pointer to key array to unpack into |
56 | * @size_t sz@ = number of bits to read (elements in array) |
57 | * @FILE *fp@ = stream to read from |
58 | * |
59 | * Returns: --- |
60 | * |
61 | * Use: Reads a number of bits into an array. The least significant |
62 | * bits of the final word are cleared to zero. |
63 | */ |
64 | |
65 | void tx_getBits(unsigned char *k, size_t sz, FILE *fp) |
66 | { |
67 | int i = 0; |
68 | unsigned char a = 0; |
69 | unsigned int ch; |
70 | size_t wsz = (size_t)((sz + 7ul) & ~7ul); |
71 | int t; |
72 | |
73 | while ((t = getc(fp)) != EOF) { |
74 | |
75 | /* --- Allow separators for readbility --- */ |
76 | |
77 | if (t == '-') |
78 | continue; |
79 | |
80 | /* --- Standard converting-from-hex-digit code --- * |
81 | * |
82 | * Assumes that 'a'--'f' and 'A'--'F' are contiguous and in order, in |
83 | * addition to the guarantee that '0'--'9' are like this. The assumption |
84 | * is true in ASCII (and character sets based thereon) and EBCDIC. |
85 | */ |
86 | |
87 | ch = (unsigned)t; |
88 | ch -= '0'; |
89 | if (ch > 9) ch -= 'A' - '0' - 10; |
90 | if (ch > 15) ch -= 'a' - 'A'; |
91 | if (ch > 15) break; |
92 | |
93 | /* --- Accumulate and maybe store --- */ |
94 | |
95 | a = (a << 4) | ch; |
96 | i++; |
97 | sz -= 4, wsz -= 4; |
98 | if ((i & 1) == 0) |
99 | *k++ = a, a = 0; |
100 | if (!sz) |
101 | break; |
102 | } |
103 | |
104 | /* --- Pad the rest out with zeros --- */ |
105 | |
106 | while (wsz) { |
107 | a <<= 4; |
108 | i++; |
109 | wsz -= 4; |
110 | if ((i & 1) == 0) |
111 | *k++ = a, a = 0; |
112 | } |
113 | } |
114 | |
115 | /* --- @tx_putBits@ --- * |
116 | * |
117 | * Arguments: @unsigned char *k@ = pointer to key block |
118 | * @size_t sz@ = number of bits to write |
119 | * @FILE *fp@ = pointer to stream to write on |
120 | * |
121 | * Returns: --- |
122 | * |
123 | * Use: Complements @tx_getBits@ above. Writes a number of bits |
124 | * to a file in an easy-to-read and transportable format (hex!) |
125 | */ |
126 | |
127 | void tx_putBits(unsigned char *k, size_t sz, FILE *fp) |
128 | { |
129 | const static char hex[16] = "0123456789abcdef"; |
130 | size_t dash; |
131 | size_t d; |
132 | unsigned char i; |
133 | |
134 | /* --- Don't do anything unless we have to --- */ |
135 | |
136 | if (!sz) |
137 | return; |
138 | |
139 | /* --- Now decide where to `dash' the output --- */ |
140 | |
141 | if (sz % 32 == 0) |
142 | dash = 4; |
143 | else if (sz % 40 == 0) |
144 | dash = 5; |
145 | else |
146 | dash = 0; |
147 | |
148 | /* --- Start writing values out --- */ |
149 | |
150 | d = dash; |
151 | |
152 | for (;;) { |
153 | |
154 | /* --- Write next byte out --- */ |
155 | |
156 | i = *k++; |
157 | putc(hex[(i >> 4) & 0x0fu], fp); |
158 | putc(hex[(i >> 0) & 0x0fu], fp); |
159 | |
160 | /* --- If done, stop now --- */ |
161 | |
162 | if (sz -= 8, sz == 0) |
163 | break; |
164 | |
165 | /* --- If need a dash, print one --- */ |
166 | |
167 | if (!--d) { |
168 | putc('-', fp); |
169 | d = dash; |
170 | } |
171 | } |
172 | |
173 | /* --- Print the final newline --- */ |
174 | |
175 | fputc('\n', fp); |
176 | } |
177 | |
178 | /*----- That's all, folks -------------------------------------------------*/ |