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Build: Overhaul build system.
[mLib] / crc-mktab.c
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b7580524 1/* -*-c-*-
2 *
8656dc50 3 * $Id: crc-mktab.c,v 1.6 2004/04/08 01:36:11 mdw Exp $
b7580524 4 *
5 * Build CRC tables
6 *
7 * (c) 2000 Straylight/Edgeware
8 */
9
d4efbcd9 10/*----- Licensing notice --------------------------------------------------*
b7580524 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.
d4efbcd9 18 *
b7580524 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.
d4efbcd9 23 *
b7580524 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
b7580524 30/*----- Header files ------------------------------------------------------*/
31
a0150d8d
MW
32#include "config.h"
33
b7580524 34#include <ctype.h>
35#include <errno.h>
36#include <limits.h>
37#include <stdarg.h>
38#include <stdio.h>
39#include <stdlib.h>
40#include <string.h>
41
42#include "mdwopt.h"
43#include "quis.h"
44#include "report.h"
45
46/*----- Static variables --------------------------------------------------*/
47
48static unsigned long poly = 0;
49static const char *guard = 0;
50static unsigned bits = 0;
51static unsigned chunk = 8;
52static const char *file = 0;
53static unsigned flags = 0;
54static const char *sym = 0;
55static const char *type = 0;
56static const char *inc = 0;
57static FILE *fp;
58
393cf1d9 59#define f_bogus 1u
60#define f_ctab 2u
61#define f_reverse 4u
b7580524 62
63#define BSCOL 72
64
65/*----- Main code ---------------------------------------------------------*/
66
67static unsigned long getint(const char *p, unsigned long max,
68 const char *what)
69{
70 char *pp;
71 unsigned long x = strtoul(p, &pp, 0);
72 if (*pp || (max && x > max))
73 die(EXIT_FAILURE, "bad %s `%s'", what, p);
74 return (x);
75}
76
77static void version(FILE *fp)
78{
79 pquis(fp, "$, mLib version " VERSION "\n");
80}
81
82static void usage(FILE *fp)
83{
6f444bda 84 pquis(fp, "Usage: $ [-cr] [-o FILE] [-g GUARD] [-s SYM] [-i HEADER]\n\
d4efbcd9 85 [-t TYPE] [-b BITS] [-B BITS] [-p POLY]\n");
b7580524 86}
87
88static void help(FILE *fp)
89{
90 version(fp);
91 putc('\n', stdout);
92 usage(fp);
93 fputs("\n\
94Emits a table containing precomuted values for CRC algorithms. A number\n\
95of options are provided:\n\
96\n\
97-h, --help Show this help text.\n\
98-v, --version Show the program's version number.\n\
99-u, --usage Show a terse usage message.\n\
100\n\
101-c, --c-source Emit a C source file rather than a header.\n\
102-b, --bits=BITS Emit a table for a BITS bits-wide CRC.\n\
103-B, --bit-chunk=BITS Emit a table to process BITS bits at a time.\n\
104-p, --polynomial=POLY Use the POLY as the dividing polynomial.\n\
105-r, --reverse Create a `reversed' CRC table.\n\
106-g, --guard=GUARD Use GUARD as a multiple-inclusion guard constant.\n\
6f444bda 107-i, --include=HEADER Include HEADER at top of C source file.\n\
108-s, --symbol=SYM Name the generated table SYM.\n\
b7580524 109-t, --type=TYPE Give the table entries type TYPE in C source.\n\
110-o, --output=FILE Write the output to FILE.\n\
111", stdout);
112}
113
114unsigned long reflect(unsigned long x, unsigned b)
115{
116 unsigned long y = 0;
117 unsigned long xm, ym;
118 unsigned i;
119 if (!(flags & f_reverse))
120 return (x);
121 xm = 1;
122 ym = 1 << (b - 1);
123 for (i = 0; i < b; i++) {
124 if (x & xm)
125 y |= ym;
126 xm <<= 1;
127 ym >>= 1;
128 }
129 return (y);
130}
131
132int main(int argc, char *argv[])
133{
134 unsigned n, t, nw;
135 unsigned max, i;
136 unsigned long mask;
137
138 ego(argv[0]);
139
140 for (;;) {
141 static struct option opts[] = {
142 { "help", 0, 0, 'h' },
143 { "version", 0, 0, 'v' },
144 { "usage", 0, 0, 'u' },
145
146 { "output", OPTF_ARGREQ, 0, 'o' },
147 { "c-source", 0, 0, 'c' },
148 { "symbol", OPTF_ARGREQ, 0, 's' },
149 { "type", OPTF_ARGREQ, 0, 't' },
150 { "include", OPTF_ARGREQ, 0, 'i' },
151 { "guard", OPTF_ARGREQ, 0, 'g' },
152
153 { "bits", OPTF_ARGREQ, 0, 'b' },
154 { "bit-chunk", OPTF_ARGREQ, 0, 'B' },
155 { "polynomial", OPTF_ARGREQ, 0, 'p' },
156 { "reverse", 0, 0, 'r' },
157
158 { 0, 0, 0, 0 }
159 };
160 int i = mdwopt(argc, argv, "hvu o:cs:t:i:g: b:B:p:r", opts, 0, 0, 0);
161
162 if (i < 0)
163 break;
164 switch (i) {
165 case 'h':
166 help(stdout);
167 exit(0);
168 case 'v':
169 version(stdout);
170 exit(0);
171 case 'u':
172 usage(stdout);
173 exit(0);
174
175 case 'o':
176 file = optarg;
177 break;
178 case 'c':
179 flags |= f_ctab;
180 break;
181 case 's':
182 sym = optarg;
183 break;
184 case 't':
185 type = optarg;
186 break;
187 case 'i':
188 inc = optarg;
189 break;
190 case 'g':
191 guard = optarg;
192 break;
193
194 case 'b':
195 bits = getint(optarg, 32, "CRC width");
196 break;
197 case 'B':
198 chunk = getint(optarg, 32, "chunk size");
199 break;
200 case 'p':
201 poly = getint(optarg, 0xffffffff, "CRC poly");
202 break;
203 case 'r':
204 flags |= f_reverse;
205 break;
206
207 default:
208 flags |= f_bogus;
209 break;
210 }
211 }
212 if ((flags & f_bogus) || optind != argc) {
213 usage(stderr);
214 exit(EXIT_FAILURE);
215 }
216
217 /* --- Sort out the various parameters --- */
218
219 if (!poly) {
220 switch (bits) {
221 case 16:
222 if (flags & f_reverse)
223 poly = 0x8408;
224 else
225 poly = 0x1021;
226 break;
227 case 32:
b7580524 228 poly = 0x04c11db7;
229 flags |= f_reverse;
230 bits = 32;
231 break;
000ba0de 232 case 0:
233 die(EXIT_FAILURE, "no polynomial or bit width set");
234 break;
b7580524 235 default:
236 die(EXIT_FAILURE, "no standard polynomials for %u bits", bits);
237 break;
238 }
239 }
240
241 if (!bits) {
242 unsigned long x = poly;
243 while (x > 1) {
244 x >>= 8;
245 bits += 8;
246 }
247 }
0521f473 248 nw = (bits + 3)/4;
b7580524 249
250 if ((flags & f_ctab) && !type)
251 type = bits > 16 ? "unsigned long" : "unsigned short";
252
253 /* --- Start output --- */
254
255 if (!file)
256 fp = stdout;
257 else {
258 if (!(flags & f_ctab) && !guard) {
259 char *p;
260 const char *q;
261 if ((p = malloc(strlen(file) + 1)) == 0)
262 die(EXIT_FAILURE, "not enough memory");
263 guard = p;
264 for (q = file; *q; p++, q++) {
265 if (isalnum((unsigned char)*q))
0521f473 266 *p = toupper((unsigned char)*q);
b7580524 267 else
268 *p = '_';
269 }
270 *p++ = 0;
271 }
272 if ((fp = fopen(file, "w")) == 0)
273 die(EXIT_FAILURE, "couldn't write `%s': %s", file, strerror(errno));
274 }
275
276 if (!sym)
277 sym = (flags & f_ctab) ? "crctab" : "CRC_TAB";
278
279 /* --- Dump out the first chunk of the file --- */
280
281 fprintf(fp, "\
282/* -*-c-*-\n\
283 *\n\
284 * CRC table (poly = %0*lx%s) [generated]\n\
285 */\n\
286\n",
287 nw, poly, flags & f_reverse ? "; reversed" : "");
288
289 if (flags & f_ctab) {
290 if (inc)
291 fprintf(fp, "#include \"%s\"\n\n", inc);
292 fprintf(fp, "%s %s[] = {\n", type, sym);
293 } else {
294 int n;
295 if (guard)
296 fprintf(fp, "#ifndef %s\n#define %s\n\n", guard, guard);
297 n = fprintf(fp, "#define %s {", sym);
298 while (n < BSCOL) {
299 fputc('\t', fp);
300 n = (n + 8) & ~7;
301 }
302 fputc('\n', fp);
303 }
304
305 /* --- Sort out the line width --- */
306
307 n = 1;
308 while (2 + n * (nw + 4) < BSCOL)
309 n <<= 1;
310 n >>= 1;
0521f473 311 max = 1 << chunk;
312 if (n > max)
313 n = max;
b7580524 314 t = 0;
315 while (((1 + n * (nw + 4)) & ~7) + 8 * t < BSCOL)
316 t++;
317
318 /* --- Start grinding --- */
319
b7580524 320 mask = 0xffffffff >> (32 - bits);
321 fputc(' ', fp);
322 for (i = 0; i < max; i++) {
0521f473 323 unsigned long x, y, z;
b7580524 324 unsigned j;
0521f473 325 unsigned ni, nn;
326
327 x = reflect(i, chunk);
328 y = 0;
329 nn = chunk;
330 while (nn) {
331 ni = bits;
332 if (ni > nn)
333 ni = nn;
334 z = (x >> (nn - ni)) & (0xffffffff >> (32 - ni));
335 y ^= z << (bits - ni);
336 for (j = 0; j < ni; j++)
337 y = ((y << 1) ^ (y & (1 << (bits - 1)) ? poly : 0)) & mask;
338 nn -= ni;
339 }
340 x = reflect(y, bits);
b7580524 341
342 fprintf(fp, " 0x%0*lx", nw, x);
343 if (i == max - 1) {
344 if (!(flags & f_ctab) && ((2 + n * (nw + 4)) & ~7) + 8 * t < BSCOL)
345 fputc('\t', fp);
346 } else
347 fputc(',', fp);
348 if (i + 1 == max || (i + 1)%n == 0) {
349 if (!(flags & f_ctab)) {
350 for (j = 0; j < t; j++)
351 fputc('\t', fp);
352 fputc('\\', fp);
353 }
354 fputc('\n', fp);
355 if (i + 1 != max)
356 fputc(' ', fp);
357 }
358 }
359
360 /* --- Done --- */
361
362 fputs(flags & f_ctab ? "};\n" : "}\n", fp);
363 if (!(flags & f_ctab) && guard)
364 fputs("\n#endif\n", fp);
365
366 return (0);
367}
368
369/*----- That's all, folks -------------------------------------------------*/