5 * (c) 2000 Straylight/Edgeware
8 /*----- Licensing notice --------------------------------------------------*
10 * This file is part of the mLib utilities library.
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.
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.
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,
28 /*----- Header files ------------------------------------------------------*/
45 /*----- Static variables --------------------------------------------------*/
47 static unsigned long poly = 0;
48 static const char *guard = 0;
49 static unsigned bits = 0;
50 static unsigned chunk = 8;
51 static const char *file = 0;
52 static unsigned flags = 0;
53 static const char *sym = 0;
54 static const char *type = 0;
55 static const char *inc = 0;
65 /*----- Main code ---------------------------------------------------------*/
67 static unsigned long getint(const char *p, unsigned long max,
71 unsigned long x = strtoul(p, &pp, 0);
72 if (*pp || (max && x > max))
73 die(EXIT_FAILURE, "bad %s `%s'", what, p);
77 static void version(FILE *fp)
79 pquis(fp, "$, mLib version " VERSION "\n");
82 static void usage(FILE *fp)
84 pquis(fp, "Usage: $ [-Ccr] [-o FILE] [-g GUARD] [-s SYM] [-i HEADER]\n\
85 [-t TYPE] [-b BITS] [-B BITS] [-p POLY]\n");
88 static void help(FILE *fp)
94 Emits a table containing precomuted values for CRC algorithms. A number\n\
95 of options are provided:\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\
101 -c, --c-source Emit a C source file rather than a header.\n\
102 -C, --const Declare table to be `const' (only useful with `-c').\n\
103 -b, --bits=BITS Emit a table for a BITS bits-wide CRC.\n\
104 -B, --bit-chunk=BITS Emit a table to process BITS bits at a time.\n\
105 -p, --polynomial=POLY Use the POLY as the dividing polynomial.\n\
106 -r, --reverse Create a `reversed' CRC table.\n\
107 -g, --guard=GUARD Use GUARD as a multiple-inclusion guard constant.\n\
108 -i, --include=HEADER Include HEADER at top of C source file.\n\
109 -s, --symbol=SYM Name the generated table SYM.\n\
110 -t, --type=TYPE Give the table entries type TYPE in C source.\n\
111 -o, --output=FILE Write the output to FILE.\n\
115 unsigned long reflect(unsigned long x, unsigned b)
118 unsigned long xm, ym;
120 if (!(flags & f_reverse))
124 for (i = 0; i < b; i++) {
133 int main(int argc, char *argv[])
142 static struct option opts[] = {
143 { "help", 0, 0, 'h' },
144 { "version", 0, 0, 'v' },
145 { "usage", 0, 0, 'u' },
147 { "output", OPTF_ARGREQ, 0, 'o' },
148 { "c-source", 0, 0, 'c' },
149 { "const", 0, 0, 'C' },
150 { "symbol", OPTF_ARGREQ, 0, 's' },
151 { "type", OPTF_ARGREQ, 0, 't' },
152 { "include", OPTF_ARGREQ, 0, 'i' },
153 { "guard", OPTF_ARGREQ, 0, 'g' },
155 { "bits", OPTF_ARGREQ, 0, 'b' },
156 { "bit-chunk", OPTF_ARGREQ, 0, 'B' },
157 { "polynomial", OPTF_ARGREQ, 0, 'p' },
158 { "reverse", 0, 0, 'r' },
162 int i = mdwopt(argc, argv, "hvu o:cCs:t:i:g: b:B:p:r", opts, 0, 0, 0);
200 bits = getint(optarg, 32, "CRC width");
203 chunk = getint(optarg, 32, "chunk size");
206 poly = getint(optarg, 0xffffffff, "CRC poly");
217 if ((flags & f_bogus) || optind != argc) {
222 /* --- Sort out the various parameters --- */
227 if (flags & f_reverse)
238 die(EXIT_FAILURE, "no polynomial or bit width set");
241 die(EXIT_FAILURE, "no standard polynomials for %u bits", bits);
247 unsigned long x = poly;
255 if ((flags & f_ctab) && !type)
256 type = bits > 16 ? "unsigned long" : "unsigned short";
258 /* --- Start output --- */
263 if (!(flags & f_ctab) && !guard) {
266 if ((p = malloc(strlen(file) + 1)) == 0)
267 die(EXIT_FAILURE, "not enough memory");
269 for (q = file; *q; p++, q++) {
277 if ((fp = fopen(file, "w")) == 0)
278 die(EXIT_FAILURE, "couldn't write `%s': %s", file, strerror(errno));
282 sym = (flags & f_ctab) ? "crctab" : "CRC_TAB";
284 /* --- Dump out the first chunk of the file --- */
289 * CRC table (poly = %0*lx%s) [generated]\n\
292 nw, poly, flags & f_reverse ? "; reversed" : "");
294 if (flags & f_ctab) {
296 fprintf(fp, "#include \"%s\"\n\n", inc);
297 fprintf(fp, "%s%s %s[] = {\n",
298 (flags&f_const) ? "const " : "", type, sym);
302 fprintf(fp, "#ifndef %s\n#define %s\n\n", guard, guard);
303 n = fprintf(fp, "#define %s {", sym);
311 /* --- Sort out the line width --- */
314 while (2 + n * (nw + 4) < BSCOL)
321 while (((1 + n * (nw + 4)) & ~7) + 8 * t < BSCOL)
324 /* --- Start grinding --- */
326 mask = 0xffffffff >> (32 - bits);
328 for (i = 0; i < max; i++) {
329 unsigned long x, y, z;
333 x = reflect(i, chunk);
340 z = (x >> (nn - ni)) & (0xffffffff >> (32 - ni));
341 y ^= z << (bits - ni);
342 for (j = 0; j < ni; j++)
343 y = ((y << 1) ^ (y & (1 << (bits - 1)) ? poly : 0)) & mask;
346 x = reflect(y, bits);
348 fprintf(fp, " 0x%0*lx", nw, x);
350 if (!(flags & f_ctab) && ((2 + n * (nw + 4)) & ~7) + 8 * t < BSCOL)
354 if (i + 1 == max || (i + 1)%n == 0) {
355 if (!(flags & f_ctab)) {
356 for (j = 0; j < t; j++)
368 fputs(flags & f_ctab ? "};\n" : "}\n", fp);
369 if (!(flags & f_ctab) && guard)
370 fputs("\n#endif\n", fp);
375 /*----- That's all, folks -------------------------------------------------*/