| 1 | /* -*-c-*- |
| 2 | * |
| 3 | * $Id: tx.c,v 1.2 1997/08/04 10:24:25 mdw Exp $ |
| 4 | * |
| 5 | * Transfer for keys and other large integers |
| 6 | * |
| 7 | * (c) 1997 Mark Wooding |
| 8 | */ |
| 9 | |
| 10 | /*----- Licensing 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 Foundation, |
| 26 | * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. |
| 27 | */ |
| 28 | |
| 29 | /*----- Revision history --------------------------------------------------* |
| 30 | * |
| 31 | * $Log: tx.c,v $ |
| 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 |
| 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 -------------------------------------------------*/ |