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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
52static const char encodemap[] = { "0123456789abcdef" };
53
54static 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
79void 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
111void 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
163void 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
176int 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 -------------------------------------------------*/