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Headers: Guard inclusion of mLib headers.
[mLib] / crc-mktab.c
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b7580524 1/* -*-c-*-
2 *
b7580524 3 * Build CRC tables
4 *
5 * (c) 2000 Straylight/Edgeware
6 */
7
d4efbcd9 8/*----- Licensing notice --------------------------------------------------*
b7580524 9 *
10 * This file is part of the mLib utilities library.
11 *
12 * mLib is free software; you can redistribute it and/or modify
13 * it under the terms of the GNU Library General Public License as
14 * published by the Free Software Foundation; either version 2 of the
15 * License, or (at your option) any later version.
d4efbcd9 16 *
b7580524 17 * mLib is distributed in the hope that it will be useful,
18 * but WITHOUT ANY WARRANTY; without even the implied warranty of
19 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
20 * GNU Library General Public License for more details.
d4efbcd9 21 *
b7580524 22 * You should have received a copy of the GNU Library General Public
23 * License along with mLib; if not, write to the Free
24 * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
25 * MA 02111-1307, USA.
26 */
27
b7580524 28/*----- Header files ------------------------------------------------------*/
29
a0150d8d
MW
30#include "config.h"
31
b7580524 32#include <ctype.h>
33#include <errno.h>
34#include <limits.h>
35#include <stdarg.h>
36#include <stdio.h>
37#include <stdlib.h>
38#include <string.h>
39
40#include "mdwopt.h"
41#include "quis.h"
42#include "report.h"
43
44/*----- Static variables --------------------------------------------------*/
45
46static unsigned long poly = 0;
47static const char *guard = 0;
48static unsigned bits = 0;
49static unsigned chunk = 8;
50static const char *file = 0;
51static unsigned flags = 0;
52static const char *sym = 0;
53static const char *type = 0;
54static const char *inc = 0;
55static FILE *fp;
56
393cf1d9 57#define f_bogus 1u
58#define f_ctab 2u
59#define f_reverse 4u
b7580524 60
61#define BSCOL 72
62
63/*----- Main code ---------------------------------------------------------*/
64
65static unsigned long getint(const char *p, unsigned long max,
66 const char *what)
67{
68 char *pp;
69 unsigned long x = strtoul(p, &pp, 0);
70 if (*pp || (max && x > max))
71 die(EXIT_FAILURE, "bad %s `%s'", what, p);
72 return (x);
73}
74
75static void version(FILE *fp)
76{
77 pquis(fp, "$, mLib version " VERSION "\n");
78}
79
80static void usage(FILE *fp)
81{
6f444bda 82 pquis(fp, "Usage: $ [-cr] [-o FILE] [-g GUARD] [-s SYM] [-i HEADER]\n\
d4efbcd9 83 [-t TYPE] [-b BITS] [-B BITS] [-p POLY]\n");
b7580524 84}
85
86static void help(FILE *fp)
87{
88 version(fp);
89 putc('\n', stdout);
90 usage(fp);
91 fputs("\n\
92Emits a table containing precomuted values for CRC algorithms. A number\n\
93of options are provided:\n\
94\n\
95-h, --help Show this help text.\n\
96-v, --version Show the program's version number.\n\
97-u, --usage Show a terse usage message.\n\
98\n\
99-c, --c-source Emit a C source file rather than a header.\n\
100-b, --bits=BITS Emit a table for a BITS bits-wide CRC.\n\
101-B, --bit-chunk=BITS Emit a table to process BITS bits at a time.\n\
102-p, --polynomial=POLY Use the POLY as the dividing polynomial.\n\
103-r, --reverse Create a `reversed' CRC table.\n\
104-g, --guard=GUARD Use GUARD as a multiple-inclusion guard constant.\n\
6f444bda 105-i, --include=HEADER Include HEADER at top of C source file.\n\
106-s, --symbol=SYM Name the generated table SYM.\n\
b7580524 107-t, --type=TYPE Give the table entries type TYPE in C source.\n\
108-o, --output=FILE Write the output to FILE.\n\
109", stdout);
110}
111
112unsigned long reflect(unsigned long x, unsigned b)
113{
114 unsigned long y = 0;
115 unsigned long xm, ym;
116 unsigned i;
117 if (!(flags & f_reverse))
118 return (x);
119 xm = 1;
120 ym = 1 << (b - 1);
121 for (i = 0; i < b; i++) {
122 if (x & xm)
123 y |= ym;
124 xm <<= 1;
125 ym >>= 1;
126 }
127 return (y);
128}
129
130int main(int argc, char *argv[])
131{
132 unsigned n, t, nw;
133 unsigned max, i;
134 unsigned long mask;
135
136 ego(argv[0]);
137
138 for (;;) {
139 static struct option opts[] = {
140 { "help", 0, 0, 'h' },
141 { "version", 0, 0, 'v' },
142 { "usage", 0, 0, 'u' },
143
144 { "output", OPTF_ARGREQ, 0, 'o' },
145 { "c-source", 0, 0, 'c' },
146 { "symbol", OPTF_ARGREQ, 0, 's' },
147 { "type", OPTF_ARGREQ, 0, 't' },
148 { "include", OPTF_ARGREQ, 0, 'i' },
149 { "guard", OPTF_ARGREQ, 0, 'g' },
150
151 { "bits", OPTF_ARGREQ, 0, 'b' },
152 { "bit-chunk", OPTF_ARGREQ, 0, 'B' },
153 { "polynomial", OPTF_ARGREQ, 0, 'p' },
154 { "reverse", 0, 0, 'r' },
155
156 { 0, 0, 0, 0 }
157 };
158 int i = mdwopt(argc, argv, "hvu o:cs:t:i:g: b:B:p:r", opts, 0, 0, 0);
159
160 if (i < 0)
161 break;
162 switch (i) {
163 case 'h':
164 help(stdout);
165 exit(0);
166 case 'v':
167 version(stdout);
168 exit(0);
169 case 'u':
170 usage(stdout);
171 exit(0);
172
173 case 'o':
174 file = optarg;
175 break;
176 case 'c':
177 flags |= f_ctab;
178 break;
179 case 's':
180 sym = optarg;
181 break;
182 case 't':
183 type = optarg;
184 break;
185 case 'i':
186 inc = optarg;
187 break;
188 case 'g':
189 guard = optarg;
190 break;
191
192 case 'b':
193 bits = getint(optarg, 32, "CRC width");
194 break;
195 case 'B':
196 chunk = getint(optarg, 32, "chunk size");
197 break;
198 case 'p':
199 poly = getint(optarg, 0xffffffff, "CRC poly");
200 break;
201 case 'r':
202 flags |= f_reverse;
203 break;
204
205 default:
206 flags |= f_bogus;
207 break;
208 }
209 }
210 if ((flags & f_bogus) || optind != argc) {
211 usage(stderr);
212 exit(EXIT_FAILURE);
213 }
214
215 /* --- Sort out the various parameters --- */
216
217 if (!poly) {
218 switch (bits) {
219 case 16:
220 if (flags & f_reverse)
221 poly = 0x8408;
222 else
223 poly = 0x1021;
224 break;
225 case 32:
b7580524 226 poly = 0x04c11db7;
227 flags |= f_reverse;
228 bits = 32;
229 break;
000ba0de 230 case 0:
231 die(EXIT_FAILURE, "no polynomial or bit width set");
232 break;
b7580524 233 default:
234 die(EXIT_FAILURE, "no standard polynomials for %u bits", bits);
235 break;
236 }
237 }
238
239 if (!bits) {
240 unsigned long x = poly;
241 while (x > 1) {
242 x >>= 8;
243 bits += 8;
244 }
245 }
0521f473 246 nw = (bits + 3)/4;
b7580524 247
248 if ((flags & f_ctab) && !type)
249 type = bits > 16 ? "unsigned long" : "unsigned short";
250
251 /* --- Start output --- */
252
253 if (!file)
254 fp = stdout;
255 else {
256 if (!(flags & f_ctab) && !guard) {
257 char *p;
258 const char *q;
259 if ((p = malloc(strlen(file) + 1)) == 0)
260 die(EXIT_FAILURE, "not enough memory");
261 guard = p;
262 for (q = file; *q; p++, q++) {
263 if (isalnum((unsigned char)*q))
0521f473 264 *p = toupper((unsigned char)*q);
b7580524 265 else
266 *p = '_';
267 }
268 *p++ = 0;
269 }
270 if ((fp = fopen(file, "w")) == 0)
271 die(EXIT_FAILURE, "couldn't write `%s': %s", file, strerror(errno));
272 }
273
274 if (!sym)
275 sym = (flags & f_ctab) ? "crctab" : "CRC_TAB";
276
277 /* --- Dump out the first chunk of the file --- */
278
279 fprintf(fp, "\
280/* -*-c-*-\n\
281 *\n\
282 * CRC table (poly = %0*lx%s) [generated]\n\
283 */\n\
284\n",
285 nw, poly, flags & f_reverse ? "; reversed" : "");
286
287 if (flags & f_ctab) {
288 if (inc)
289 fprintf(fp, "#include \"%s\"\n\n", inc);
290 fprintf(fp, "%s %s[] = {\n", type, sym);
291 } else {
292 int n;
293 if (guard)
294 fprintf(fp, "#ifndef %s\n#define %s\n\n", guard, guard);
295 n = fprintf(fp, "#define %s {", sym);
296 while (n < BSCOL) {
297 fputc('\t', fp);
298 n = (n + 8) & ~7;
299 }
300 fputc('\n', fp);
301 }
302
303 /* --- Sort out the line width --- */
304
305 n = 1;
306 while (2 + n * (nw + 4) < BSCOL)
307 n <<= 1;
308 n >>= 1;
0521f473 309 max = 1 << chunk;
310 if (n > max)
311 n = max;
b7580524 312 t = 0;
313 while (((1 + n * (nw + 4)) & ~7) + 8 * t < BSCOL)
314 t++;
315
316 /* --- Start grinding --- */
317
b7580524 318 mask = 0xffffffff >> (32 - bits);
319 fputc(' ', fp);
320 for (i = 0; i < max; i++) {
0521f473 321 unsigned long x, y, z;
b7580524 322 unsigned j;
0521f473 323 unsigned ni, nn;
324
325 x = reflect(i, chunk);
326 y = 0;
327 nn = chunk;
328 while (nn) {
329 ni = bits;
330 if (ni > nn)
331 ni = nn;
332 z = (x >> (nn - ni)) & (0xffffffff >> (32 - ni));
333 y ^= z << (bits - ni);
334 for (j = 0; j < ni; j++)
335 y = ((y << 1) ^ (y & (1 << (bits - 1)) ? poly : 0)) & mask;
336 nn -= ni;
337 }
338 x = reflect(y, bits);
b7580524 339
340 fprintf(fp, " 0x%0*lx", nw, x);
341 if (i == max - 1) {
342 if (!(flags & f_ctab) && ((2 + n * (nw + 4)) & ~7) + 8 * t < BSCOL)
343 fputc('\t', fp);
344 } else
345 fputc(',', fp);
346 if (i + 1 == max || (i + 1)%n == 0) {
347 if (!(flags & f_ctab)) {
348 for (j = 0; j < t; j++)
349 fputc('\t', fp);
350 fputc('\\', fp);
351 }
352 fputc('\n', fp);
353 if (i + 1 != max)
354 fputc(' ', fp);
355 }
356 }
357
358 /* --- Done --- */
359
360 fputs(flags & f_ctab ? "};\n" : "}\n", fp);
361 if (!(flags & f_ctab) && guard)
362 fputs("\n#endif\n", fp);
363
364 return (0);
365}
366
367/*----- That's all, folks -------------------------------------------------*/