1833e0e2402fa28cc2bb64e2c2cd841f77300df3
3 * $Id: crc-mktab.c,v 1.5 2003/12/15 20:53:47 mdw Exp $
7 * (c) 2000 Straylight/Edgeware
10 /*----- Licensing notice --------------------------------------------------*
12 * This file is part of the mLib utilities library.
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.
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.
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,
30 /*----- Revision history --------------------------------------------------*
32 * $Log: crc-mktab.c,v $
33 * Revision 1.5 2003/12/15 20:53:47 mdw
34 * Add global unihash table; use universal hashing instead of CRC.
36 * Revision 1.4 2001/03/10 10:59:21 mdw
37 * Fix generating tables where the chunk size is longer than the
38 * polynomial. Also fix output formatting when there aren't enough entries
41 * Revision 1.3 2001/01/20 12:06:01 mdw
42 * Define flags with macros, to ensure unsignedness.
44 * Revision 1.2 2000/10/08 11:07:21 mdw
45 * With no arguments, give an error rather than spewing a big table at the
48 * Revision 1.1 2000/07/21 19:01:33 mdw
49 * Generate the CRC table rather than hardcoding it.
53 /*----- Header files ------------------------------------------------------*/
67 /*----- Static variables --------------------------------------------------*/
69 static unsigned long poly
= 0;
70 static const char *guard
= 0;
71 static unsigned bits
= 0;
72 static unsigned chunk
= 8;
73 static const char *file
= 0;
74 static unsigned flags
= 0;
75 static const char *sym
= 0;
76 static const char *type
= 0;
77 static const char *inc
= 0;
86 /*----- Main code ---------------------------------------------------------*/
88 static unsigned long getint(const char *p
, unsigned long max
,
92 unsigned long x
= strtoul(p
, &pp
, 0);
93 if (*pp
|| (max
&& x
> max
))
94 die(EXIT_FAILURE
, "bad %s `%s'", what
, p
);
98 static void version(FILE *fp
)
100 pquis(fp
, "$, mLib version " VERSION
"\n");
103 static void usage(FILE *fp
)
105 pquis(fp
, "Usage: $ [-cr] [-o FILE] [-g GUARD] [-s SYM] [-i HEADER]\n\
106 [-t TYPE] [-b BITS] [-B BITS] [-p POLY]\n");
109 static void help(FILE *fp
)
115 Emits a table containing precomuted values for CRC algorithms. A number\n\
116 of options are provided:\n\
118 -h, --help Show this help text.\n\
119 -v, --version Show the program's version number.\n\
120 -u, --usage Show a terse usage message.\n\
122 -c, --c-source Emit a C source file rather than a header.\n\
123 -b, --bits=BITS Emit a table for a BITS bits-wide CRC.\n\
124 -B, --bit-chunk=BITS Emit a table to process BITS bits at a time.\n\
125 -p, --polynomial=POLY Use the POLY as the dividing polynomial.\n\
126 -r, --reverse Create a `reversed' CRC table.\n\
127 -g, --guard=GUARD Use GUARD as a multiple-inclusion guard constant.\n\
128 -i, --include=HEADER Include HEADER at top of C source file.\n\
129 -s, --symbol=SYM Name the generated table SYM.\n\
130 -t, --type=TYPE Give the table entries type TYPE in C source.\n\
131 -o, --output=FILE Write the output to FILE.\n\
135 unsigned long reflect(unsigned long x
, unsigned b
)
138 unsigned long xm
, ym
;
140 if (!(flags
& f_reverse
))
144 for (i
= 0; i
< b
; i
++) {
153 int main(int argc
, char *argv
[])
162 static struct option opts
[] = {
163 { "help", 0, 0, 'h' },
164 { "version", 0, 0, 'v' },
165 { "usage", 0, 0, 'u' },
167 { "output", OPTF_ARGREQ
, 0, 'o' },
168 { "c-source", 0, 0, 'c' },
169 { "symbol", OPTF_ARGREQ
, 0, 's' },
170 { "type", OPTF_ARGREQ
, 0, 't' },
171 { "include", OPTF_ARGREQ
, 0, 'i' },
172 { "guard", OPTF_ARGREQ
, 0, 'g' },
174 { "bits", OPTF_ARGREQ
, 0, 'b' },
175 { "bit-chunk", OPTF_ARGREQ
, 0, 'B' },
176 { "polynomial", OPTF_ARGREQ
, 0, 'p' },
177 { "reverse", 0, 0, 'r' },
181 int i
= mdwopt(argc
, argv
, "hvu o:cs:t:i:g: b:B:p:r", opts
, 0, 0, 0);
216 bits
= getint(optarg
, 32, "CRC width");
219 chunk
= getint(optarg
, 32, "chunk size");
222 poly
= getint(optarg
, 0xffffffff, "CRC poly");
233 if ((flags
& f_bogus
) || optind
!= argc
) {
238 /* --- Sort out the various parameters --- */
243 if (flags
& f_reverse
)
254 die(EXIT_FAILURE
, "no polynomial or bit width set");
257 die(EXIT_FAILURE
, "no standard polynomials for %u bits", bits
);
263 unsigned long x
= poly
;
271 if ((flags
& f_ctab
) && !type
)
272 type
= bits
> 16 ?
"unsigned long" : "unsigned short";
274 /* --- Start output --- */
279 if (!(flags
& f_ctab
) && !guard
) {
282 if ((p
= malloc(strlen(file
) + 1)) == 0)
283 die(EXIT_FAILURE
, "not enough memory");
285 for (q
= file
; *q
; p
++, q
++) {
286 if (isalnum((unsigned char)*q
))
287 *p
= toupper((unsigned char)*q
);
293 if ((fp
= fopen(file
, "w")) == 0)
294 die(EXIT_FAILURE
, "couldn't write `%s': %s", file
, strerror(errno
));
298 sym
= (flags
& f_ctab
) ?
"crctab" : "CRC_TAB";
300 /* --- Dump out the first chunk of the file --- */
305 * CRC table (poly = %0*lx%s) [generated]\n\
308 nw
, poly
, flags
& f_reverse ?
"; reversed" : "");
310 if (flags
& f_ctab
) {
312 fprintf(fp
, "#include \"%s\"\n\n", inc
);
313 fprintf(fp
, "%s %s[] = {\n", type
, sym
);
317 fprintf(fp
, "#ifndef %s\n#define %s\n\n", guard
, guard
);
318 n
= fprintf(fp
, "#define %s {", sym
);
326 /* --- Sort out the line width --- */
329 while (2 + n
* (nw
+ 4) < BSCOL
)
336 while (((1 + n
* (nw
+ 4)) & ~7) + 8 * t
< BSCOL
)
339 /* --- Start grinding --- */
341 mask
= 0xffffffff >> (32 - bits
);
343 for (i
= 0; i
< max
; i
++) {
344 unsigned long x
, y
, z
;
348 x
= reflect(i
, chunk
);
355 z
= (x
>> (nn
- ni
)) & (0xffffffff >> (32 - ni
));
356 y
^= z
<< (bits
- ni
);
357 for (j
= 0; j
< ni
; j
++)
358 y
= ((y
<< 1) ^ (y
& (1 << (bits
- 1)) ? poly
: 0)) & mask
;
361 x
= reflect(y
, bits
);
363 fprintf(fp
, " 0x%0*lx", nw
, x
);
365 if (!(flags
& f_ctab
) && ((2 + n
* (nw
+ 4)) & ~7) + 8 * t
< BSCOL
)
369 if (i
+ 1 == max
|| (i
+ 1)%n
== 0) {
370 if (!(flags
& f_ctab
)) {
371 for (j
= 0; j
< t
; j
++)
383 fputs(flags
& f_ctab ?
"};\n" : "}\n", fp
);
384 if (!(flags
& f_ctab
) && guard
)
385 fputs("\n#endif\n", fp
);
390 /*----- That's all, folks -------------------------------------------------*/