cosmopolitan/tool/hash/crctab.c

51 lines
2.6 KiB
C

/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi│
╞══════════════════════════════════════════════════════════════════════════════╡
│ Copyright 2020 Justine Alexandra Roberts Tunney │
│ │
│ This program is free software; you can redistribute it and/or modify │
│ it under the terms of the GNU General Public License as published by │
│ the Free Software Foundation; version 2 of the License. │
│ │
│ This program 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 │
│ General Public License for more details. │
│ │
│ You should have received a copy of the GNU General Public License │
│ along with this program; if not, write to the Free Software │
│ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA │
│ 02110-1301 USA │
╚─────────────────────────────────────────────────────────────────────────────*/
#include "libc/bits/bits.h"
#include "libc/fmt/conv.h"
#include "libc/macros.h"
#include "libc/nexgen32e/crc32.h"
#include "libc/runtime/runtime.h"
#include "libc/stdio/stdio.h"
/**
* @fileoverview CRC Lookup Table Generator
* @see http://reveng.sourceforge.net/crc-catalogue/17plus.htm
*/
int main(int argc, char *argv[]) {
if (argc != 2) {
fprintf(stderr, "Usage: %s POLYNOMIAL\n", argv[0]);
exit(1);
}
static uint32_t tab[256];
crc32init(tab, strtoimax(argv[1], NULL, 0));
for (unsigned i = 0; i < ARRAYLEN(tab); ++i) {
if (i > 0) {
printf(",");
if (i % 6 == 0) {
printf("\n");
}
}
printf("0x%08x", tab[i]);
}
printf("\n");
return 0;
}