--- /dev/null
+/* -*-c-*-
+ *
+ * $Id: crc-mktab.c,v 1.1 2000/07/21 19:01:33 mdw Exp $
+ *
+ * Build CRC tables
+ *
+ * (c) 2000 Straylight/Edgeware
+ */
+
+/*----- Licensing notice --------------------------------------------------*
+ *
+ * This file is part of the mLib utilities library.
+ *
+ * mLib is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU Library General Public License as
+ * published by the Free Software Foundation; either version 2 of the
+ * License, or (at your option) any later version.
+ *
+ * mLib is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public
+ * License along with mLib; if not, write to the Free
+ * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
+ * MA 02111-1307, USA.
+ */
+
+/*----- Revision history --------------------------------------------------*
+ *
+ * $Log: crc-mktab.c,v $
+ * Revision 1.1 2000/07/21 19:01:33 mdw
+ * Generate the CRC table rather than hardcoding it.
+ *
+ */
+
+/*----- Header files ------------------------------------------------------*/
+
+#include <ctype.h>
+#include <errno.h>
+#include <limits.h>
+#include <stdarg.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "mdwopt.h"
+#include "quis.h"
+#include "report.h"
+
+/*----- Static variables --------------------------------------------------*/
+
+static unsigned long poly = 0;
+static const char *guard = 0;
+static unsigned bits = 0;
+static unsigned chunk = 8;
+static const char *file = 0;
+static unsigned flags = 0;
+static const char *sym = 0;
+static const char *type = 0;
+static const char *inc = 0;
+static FILE *fp;
+
+enum {
+ f_bogus = 1,
+ f_ctab = 2,
+ f_reverse = 4
+};
+
+#define BSCOL 72
+
+/*----- Main code ---------------------------------------------------------*/
+
+static unsigned long getint(const char *p, unsigned long max,
+ const char *what)
+{
+ char *pp;
+ unsigned long x = strtoul(p, &pp, 0);
+ if (*pp || (max && x > max))
+ die(EXIT_FAILURE, "bad %s `%s'", what, p);
+ return (x);
+}
+
+static void version(FILE *fp)
+{
+ pquis(fp, "$, mLib version " VERSION "\n");
+}
+
+static void usage(FILE *fp)
+{
+ pquis(fp, "Usage: $ [-cr] [-g guard] [-o file] [-b bits] [-p poly]\n");
+}
+
+static void help(FILE *fp)
+{
+ version(fp);
+ putc('\n', stdout);
+ usage(fp);
+ fputs("\n\
+Emits a table containing precomuted values for CRC algorithms. A number\n\
+of options are provided:\n\
+\n\
+-h, --help Show this help text.\n\
+-v, --version Show the program's version number.\n\
+-u, --usage Show a terse usage message.\n\
+\n\
+-c, --c-source Emit a C source file rather than a header.\n\
+-b, --bits=BITS Emit a table for a BITS bits-wide CRC.\n\
+-B, --bit-chunk=BITS Emit a table to process BITS bits at a time.\n\
+-p, --polynomial=POLY Use the POLY as the dividing polynomial.\n\
+-r, --reverse Create a `reversed' CRC table.\n\
+-g, --guard=GUARD Use GUARD as a multiple-inclusion guard constant.\n\
+-s, --symbol=SYM Name the generated table SYM\n\
+-t, --type=TYPE Give the table entries type TYPE in C source.\n\
+-o, --output=FILE Write the output to FILE.\n\
+", stdout);
+}
+
+unsigned long reflect(unsigned long x, unsigned b)
+{
+ unsigned long y = 0;
+ unsigned long xm, ym;
+ unsigned i;
+ if (!(flags & f_reverse))
+ return (x);
+ xm = 1;
+ ym = 1 << (b - 1);
+ for (i = 0; i < b; i++) {
+ if (x & xm)
+ y |= ym;
+ xm <<= 1;
+ ym >>= 1;
+ }
+ return (y);
+}
+
+int main(int argc, char *argv[])
+{
+ unsigned n, t, nw;
+ unsigned max, i;
+ unsigned long mask;
+
+ ego(argv[0]);
+
+ for (;;) {
+ static struct option opts[] = {
+ { "help", 0, 0, 'h' },
+ { "version", 0, 0, 'v' },
+ { "usage", 0, 0, 'u' },
+
+ { "output", OPTF_ARGREQ, 0, 'o' },
+ { "c-source", 0, 0, 'c' },
+ { "symbol", OPTF_ARGREQ, 0, 's' },
+ { "type", OPTF_ARGREQ, 0, 't' },
+ { "include", OPTF_ARGREQ, 0, 'i' },
+ { "guard", OPTF_ARGREQ, 0, 'g' },
+
+ { "bits", OPTF_ARGREQ, 0, 'b' },
+ { "bit-chunk", OPTF_ARGREQ, 0, 'B' },
+ { "polynomial", OPTF_ARGREQ, 0, 'p' },
+ { "reverse", 0, 0, 'r' },
+
+ { 0, 0, 0, 0 }
+ };
+ int i = mdwopt(argc, argv, "hvu o:cs:t:i:g: b:B:p:r", opts, 0, 0, 0);
+
+ if (i < 0)
+ break;
+ switch (i) {
+ case 'h':
+ help(stdout);
+ exit(0);
+ case 'v':
+ version(stdout);
+ exit(0);
+ case 'u':
+ usage(stdout);
+ exit(0);
+
+ case 'o':
+ file = optarg;
+ break;
+ case 'c':
+ flags |= f_ctab;
+ break;
+ case 's':
+ sym = optarg;
+ break;
+ case 't':
+ type = optarg;
+ break;
+ case 'i':
+ inc = optarg;
+ break;
+ case 'g':
+ guard = optarg;
+ break;
+
+ case 'b':
+ bits = getint(optarg, 32, "CRC width");
+ break;
+ case 'B':
+ chunk = getint(optarg, 32, "chunk size");
+ break;
+ case 'p':
+ poly = getint(optarg, 0xffffffff, "CRC poly");
+ break;
+ case 'r':
+ flags |= f_reverse;
+ break;
+
+ default:
+ flags |= f_bogus;
+ break;
+ }
+ }
+ if ((flags & f_bogus) || optind != argc) {
+ usage(stderr);
+ exit(EXIT_FAILURE);
+ }
+
+ /* --- Sort out the various parameters --- */
+
+ if (!poly) {
+ switch (bits) {
+ case 16:
+ if (flags & f_reverse)
+ poly = 0x8408;
+ else
+ poly = 0x1021;
+ break;
+ case 32:
+ case 0:
+ poly = 0x04c11db7;
+ flags |= f_reverse;
+ bits = 32;
+ break;
+ default:
+ die(EXIT_FAILURE, "no standard polynomials for %u bits", bits);
+ break;
+ }
+ }
+
+ if (!bits) {
+ unsigned long x = poly;
+ while (x > 1) {
+ x >>= 8;
+ bits += 8;
+ }
+ }
+ nw = bits/4;
+
+ if ((flags & f_ctab) && !type)
+ type = bits > 16 ? "unsigned long" : "unsigned short";
+
+ /* --- Start output --- */
+
+ if (!file)
+ fp = stdout;
+ else {
+ if (!(flags & f_ctab) && !guard) {
+ char *p;
+ const char *q;
+ if ((p = malloc(strlen(file) + 1)) == 0)
+ die(EXIT_FAILURE, "not enough memory");
+ guard = p;
+ for (q = file; *q; p++, q++) {
+ if (isalnum((unsigned char)*q))
+ *p = *q;
+ else
+ *p = '_';
+ }
+ *p++ = 0;
+ }
+ if ((fp = fopen(file, "w")) == 0)
+ die(EXIT_FAILURE, "couldn't write `%s': %s", file, strerror(errno));
+ }
+
+ if (!sym)
+ sym = (flags & f_ctab) ? "crctab" : "CRC_TAB";
+
+ /* --- Dump out the first chunk of the file --- */
+
+ fprintf(fp, "\
+/* -*-c-*-\n\
+ *\n\
+ * CRC table (poly = %0*lx%s) [generated]\n\
+ */\n\
+\n",
+ nw, poly, flags & f_reverse ? "; reversed" : "");
+
+ if (flags & f_ctab) {
+ if (inc)
+ fprintf(fp, "#include \"%s\"\n\n", inc);
+ fprintf(fp, "%s %s[] = {\n", type, sym);
+ } else {
+ int n;
+ if (guard)
+ fprintf(fp, "#ifndef %s\n#define %s\n\n", guard, guard);
+ n = fprintf(fp, "#define %s {", sym);
+ while (n < BSCOL) {
+ fputc('\t', fp);
+ n = (n + 8) & ~7;
+ }
+ fputc('\n', fp);
+ }
+
+ /* --- Sort out the line width --- */
+
+ n = 1;
+ while (2 + n * (nw + 4) < BSCOL)
+ n <<= 1;
+ n >>= 1;
+ t = 0;
+ while (((1 + n * (nw + 4)) & ~7) + 8 * t < BSCOL)
+ t++;
+
+ /* --- Start grinding --- */
+
+ max = 1 << chunk;
+ mask = 0xffffffff >> (32 - bits);
+ fputc(' ', fp);
+ for (i = 0; i < max; i++) {
+ unsigned long x;
+ unsigned j;
+
+ x = reflect(i, chunk) << (bits - chunk);
+ for (j = 0; j < chunk; j++)
+ x = ((x << 1) ^ (x & (1 << (bits - 1)) ? poly : 0)) & mask;
+ x = reflect(x, bits);
+
+ fprintf(fp, " 0x%0*lx", nw, x);
+ if (i == max - 1) {
+ if (!(flags & f_ctab) && ((2 + n * (nw + 4)) & ~7) + 8 * t < BSCOL)
+ fputc('\t', fp);
+ } else
+ fputc(',', fp);
+ if (i + 1 == max || (i + 1)%n == 0) {
+ if (!(flags & f_ctab)) {
+ for (j = 0; j < t; j++)
+ fputc('\t', fp);
+ fputc('\\', fp);
+ }
+ fputc('\n', fp);
+ if (i + 1 != max)
+ fputc(' ', fp);
+ }
+ }
+
+ /* --- Done --- */
+
+ fputs(flags & f_ctab ? "};\n" : "}\n", fp);
+ if (!(flags & f_ctab) && guard)
+ fputs("\n#endif\n", fp);
+
+ return (0);
+}
+
+/*----- That's all, folks -------------------------------------------------*/
~mdw / mLib / blobdiff