| 1 | /* -*-c-*- |
| 2 | * |
| 3 | * $Id: hex.c,v 1.2 2003/05/16 00:22:58 mdw Exp $ |
| 4 | * |
| 5 | * Hexadecimal encoding and decoding. |
| 6 | * |
| 7 | * (c) 2001 Straylight/Edgeware |
| 8 | */ |
| 9 | |
| 10 | /*----- Licensing notice --------------------------------------------------* |
| 11 | * |
| 12 | * This file is part of the mLib utilities library. |
| 13 | * |
| 14 | * mLib 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 | * mLib 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 mLib; 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: hex.c,v $ |
| 33 | * Revision 1.2 2003/05/16 00:22:58 mdw |
| 34 | * Test base64 and hex encoding. |
| 35 | * |
| 36 | * Revision 1.1 2002/01/13 13:26:30 mdw |
| 37 | * New hex encoding stuff. |
| 38 | * |
| 39 | */ |
| 40 | |
| 41 | /*----- Header files ------------------------------------------------------*/ |
| 42 | |
| 43 | #include <stdio.h> |
| 44 | #include <stdlib.h> |
| 45 | #include <string.h> |
| 46 | |
| 47 | #include "dstr.h" |
| 48 | #include "hex.h" |
| 49 | |
| 50 | /*----- Important tables --------------------------------------------------*/ |
| 51 | |
| 52 | static const char encodemap[] = { "0123456789abcdef" }; |
| 53 | |
| 54 | static const signed char decodemap[] = { |
| 55 | -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /* 0x */ |
| 56 | -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /* 1x */ |
| 57 | -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /* 2x */ |
| 58 | 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 1, -1, -1, -1, -1, -1, /* 3x */ |
| 59 | -1, 10, 11, 12, 13, 14, 15, -1, -1, -1, -1, -1, -1, -1, -1, -1, /* 4x */ |
| 60 | -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /* 5x */ |
| 61 | -1, 10, 11, 12, 13, 14, 15, -1, -1, -1, -1, -1, -1, -1, -1, -1, /* 6x */ |
| 62 | -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /* 7x */ |
| 63 | }; |
| 64 | |
| 65 | /*----- Main code ---------------------------------------------------------*/ |
| 66 | |
| 67 | /* --- @hex_encode@ --- * |
| 68 | * |
| 69 | * Arguments: @hex_ctx *ctx@ = pointer to a context block |
| 70 | * @const void *p@ = pointer to a source buffer |
| 71 | * @size_t sz@ = size of the source buffer |
| 72 | * @dstr *d@ = pointer to destination string |
| 73 | * |
| 74 | * Returns: --- |
| 75 | * |
| 76 | * Use: Encodes a binary string in hex. |
| 77 | */ |
| 78 | |
| 79 | void hex_encode(hex_ctx *ctx, const void *p, size_t sz, dstr *d) |
| 80 | { |
| 81 | if (p) { |
| 82 | const unsigned char *src = p; |
| 83 | |
| 84 | while (sz) { |
| 85 | unsigned x = *src++; |
| 86 | sz--; |
| 87 | DPUTC(d, encodemap[(x >> 4) & 0xf]); |
| 88 | DPUTC(d, encodemap[(x >> 0) & 0xf]); |
| 89 | ctx->lnlen += 2; |
| 90 | if (ctx->maxline && ctx->lnlen >= ctx->maxline) { |
| 91 | dstr_puts(d, ctx->indent); |
| 92 | ctx->lnlen = 0; |
| 93 | } |
| 94 | } |
| 95 | } |
| 96 | } |
| 97 | |
| 98 | /* --- @hex_decode@ --- * |
| 99 | * |
| 100 | * Arguments: @hex_ctx *ctx@ = pointer to a context block |
| 101 | * @const void *p@ = pointer to a source buffer |
| 102 | * @size_t sz@ = size of the source buffer |
| 103 | * @dstr *d@ = pointer to destination string |
| 104 | * |
| 105 | * Returns: --- |
| 106 | * |
| 107 | * Use: Decodes a binary string in hex. Pass in a null source |
| 108 | * pointer when you thing you've finished. |
| 109 | */ |
| 110 | |
| 111 | void hex_decode(hex_ctx *ctx, const void *p, size_t sz, dstr *d) |
| 112 | { |
| 113 | if (p) { |
| 114 | unsigned long acc = ctx->acc; |
| 115 | unsigned qsz = ctx->qsz; |
| 116 | const char *src = p; |
| 117 | int ch; |
| 118 | |
| 119 | while (sz) { |
| 120 | |
| 121 | /* --- Get the next character and convert it --- */ |
| 122 | |
| 123 | ch = *src++; |
| 124 | if (ch >= 128 || ch < 0) |
| 125 | ch = -1; |
| 126 | else |
| 127 | ch = decodemap[ch]; |
| 128 | sz--; |
| 129 | if (ch == -1) |
| 130 | continue; |
| 131 | |
| 132 | /* --- Bung it in the accumulator --- */ |
| 133 | |
| 134 | acc = (acc << 4) | ch; |
| 135 | qsz++; |
| 136 | |
| 137 | /* --- Maybe write out a completed triplet --- */ |
| 138 | |
| 139 | if (qsz == 2) { |
| 140 | DPUTC(d, acc & 0xff); |
| 141 | acc = 0; |
| 142 | qsz = 0; |
| 143 | } |
| 144 | } |
| 145 | |
| 146 | ctx->acc = acc; |
| 147 | ctx->qsz = qsz; |
| 148 | } else { |
| 149 | if (ctx->qsz) |
| 150 | DPUTC(d, ctx->acc << 4); |
| 151 | } |
| 152 | } |
| 153 | |
| 154 | /* --- @hex_init@ --- * |
| 155 | * |
| 156 | * Arguments: @hex_ctx *ctx@ = pointer to context block to initialize |
| 157 | * |
| 158 | * Returns: --- |
| 159 | * |
| 160 | * Use: Initializes a hex context properly. |
| 161 | */ |
| 162 | |
| 163 | void hex_init(hex_ctx *ctx) |
| 164 | { |
| 165 | ctx->acc = 0; |
| 166 | ctx->qsz = 0; |
| 167 | ctx->lnlen = 0; |
| 168 | ctx->indent = "\n"; |
| 169 | ctx->maxline = 72; |
| 170 | } |
| 171 | |
| 172 | /*----- Test driver code --------------------------------------------------*/ |
| 173 | |
| 174 | #ifdef TEST_RIG |
| 175 | |
| 176 | int main(int argc, char *argv[]) |
| 177 | { |
| 178 | unsigned char buf[BUFSIZ]; |
| 179 | dstr d = DSTR_INIT; |
| 180 | hex_ctx ctx; |
| 181 | void (*proc)(hex_ctx *, const void *, size_t, dstr *); |
| 182 | size_t sz; |
| 183 | |
| 184 | hex_init(&ctx); |
| 185 | |
| 186 | if (argc > 1 && strcmp(argv[1], "-d") == 0) |
| 187 | proc = hex_decode; |
| 188 | else { |
| 189 | proc = hex_encode; |
| 190 | putchar('\t'); |
| 191 | ctx.indent = "\n\t"; |
| 192 | ctx.maxline = 64; |
| 193 | } |
| 194 | |
| 195 | do { |
| 196 | sz = fread(buf, 1, sizeof(buf), stdin); |
| 197 | if (sz) { |
| 198 | proc(&ctx, buf, sz, &d); |
| 199 | dstr_write(&d, stdout); |
| 200 | dstr_destroy(&d); |
| 201 | } |
| 202 | } while (sz == sizeof(buf)); |
| 203 | |
| 204 | proc(&ctx, 0, 0, &d); |
| 205 | dstr_write(&d, stdout); |
| 206 | |
| 207 | if (proc == hex_encode) |
| 208 | putchar('\n'); |
| 209 | |
| 210 | return (0); |
| 211 | } |
| 212 | |
| 213 | #endif |
| 214 | |
| 215 | /*----- That's all, folks -------------------------------------------------*/ |