chiark / gitweb /
Various manual fixes.
[mLib] / hex.c
CommitLineData
ee393574 1/* -*-c-*-
2 *
8656dc50 3 * $Id: hex.c,v 1.3 2004/04/08 01:36:11 mdw Exp $
ee393574 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
ee393574 30/*----- Header files ------------------------------------------------------*/
31
32#include <stdio.h>
33#include <stdlib.h>
34#include <string.h>
35
36#include "dstr.h"
37#include "hex.h"
38
39/*----- Important tables --------------------------------------------------*/
40
41static const char encodemap[] = { "0123456789abcdef" };
42
43static const signed char decodemap[] = {
44 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /* 0x */
45 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /* 1x */
46 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /* 2x */
47 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 1, -1, -1, -1, -1, -1, /* 3x */
48 -1, 10, 11, 12, 13, 14, 15, -1, -1, -1, -1, -1, -1, -1, -1, -1, /* 4x */
49 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /* 5x */
50 -1, 10, 11, 12, 13, 14, 15, -1, -1, -1, -1, -1, -1, -1, -1, -1, /* 6x */
51 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /* 7x */
52 };
53
54/*----- Main code ---------------------------------------------------------*/
55
56/* --- @hex_encode@ --- *
57 *
58 * Arguments: @hex_ctx *ctx@ = pointer to a context block
59 * @const void *p@ = pointer to a source buffer
60 * @size_t sz@ = size of the source buffer
61 * @dstr *d@ = pointer to destination string
62 *
63 * Returns: ---
64 *
65 * Use: Encodes a binary string in hex.
66 */
67
68void hex_encode(hex_ctx *ctx, const void *p, size_t sz, dstr *d)
69{
70 if (p) {
71 const unsigned char *src = p;
72
73 while (sz) {
74 unsigned x = *src++;
75 sz--;
76 DPUTC(d, encodemap[(x >> 4) & 0xf]);
77 DPUTC(d, encodemap[(x >> 0) & 0xf]);
78 ctx->lnlen += 2;
79 if (ctx->maxline && ctx->lnlen >= ctx->maxline) {
80 dstr_puts(d, ctx->indent);
81 ctx->lnlen = 0;
82 }
83 }
84 }
85}
86
87/* --- @hex_decode@ --- *
88 *
89 * Arguments: @hex_ctx *ctx@ = pointer to a context block
90 * @const void *p@ = pointer to a source buffer
91 * @size_t sz@ = size of the source buffer
92 * @dstr *d@ = pointer to destination string
93 *
94 * Returns: ---
95 *
96 * Use: Decodes a binary string in hex. Pass in a null source
97 * pointer when you thing you've finished.
98 */
99
100void hex_decode(hex_ctx *ctx, const void *p, size_t sz, dstr *d)
101{
102 if (p) {
103 unsigned long acc = ctx->acc;
104 unsigned qsz = ctx->qsz;
105 const char *src = p;
106 int ch;
107
108 while (sz) {
109
110 /* --- Get the next character and convert it --- */
111
112 ch = *src++;
113 if (ch >= 128 || ch < 0)
114 ch = -1;
115 else
116 ch = decodemap[ch];
117 sz--;
118 if (ch == -1)
119 continue;
120
121 /* --- Bung it in the accumulator --- */
122
123 acc = (acc << 4) | ch;
124 qsz++;
125
126 /* --- Maybe write out a completed triplet --- */
127
128 if (qsz == 2) {
129 DPUTC(d, acc & 0xff);
130 acc = 0;
131 qsz = 0;
132 }
133 }
134
135 ctx->acc = acc;
136 ctx->qsz = qsz;
137 } else {
138 if (ctx->qsz)
139 DPUTC(d, ctx->acc << 4);
140 }
141}
142
143/* --- @hex_init@ --- *
144 *
145 * Arguments: @hex_ctx *ctx@ = pointer to context block to initialize
146 *
147 * Returns: ---
148 *
149 * Use: Initializes a hex context properly.
150 */
151
152void hex_init(hex_ctx *ctx)
153{
154 ctx->acc = 0;
155 ctx->qsz = 0;
156 ctx->lnlen = 0;
157 ctx->indent = "\n";
158 ctx->maxline = 72;
159}
160
161/*----- Test driver code --------------------------------------------------*/
162
163#ifdef TEST_RIG
164
165int main(int argc, char *argv[])
166{
167 unsigned char buf[BUFSIZ];
168 dstr d = DSTR_INIT;
169 hex_ctx ctx;
d5679ed0 170 void (*proc)(hex_ctx *, const void *, size_t, dstr *);
ee393574 171 size_t sz;
172
173 hex_init(&ctx);
174
175 if (argc > 1 && strcmp(argv[1], "-d") == 0)
176 proc = hex_decode;
177 else {
178 proc = hex_encode;
179 putchar('\t');
180 ctx.indent = "\n\t";
181 ctx.maxline = 64;
182 }
183
184 do {
185 sz = fread(buf, 1, sizeof(buf), stdin);
186 if (sz) {
187 proc(&ctx, buf, sz, &d);
188 dstr_write(&d, stdout);
189 dstr_destroy(&d);
190 }
191 } while (sz == sizeof(buf));
192
193 proc(&ctx, 0, 0, &d);
194 dstr_write(&d, stdout);
195
196 if (proc == hex_encode)
197 putchar('\n');
198
199 return (0);
200}
201
202#endif
203
204/*----- That's all, folks -------------------------------------------------*/