busybox/coreutils/cksum.c

54 lines
1.1 KiB
C
Raw Normal View History

2006-04-19 02:27:28 +05:30
/* vi: set sw=4 ts=4: */
/*
* cksum - calculate the CRC32 checksum of a file
*
* Copyright (C) 2006 by Rob Sullivan, with ideas from code by Walter Harms
*
2006-04-19 02:27:28 +05:30
* Licensed under GPLv2 or later, see file LICENSE in this tarball for details. */
#include "busybox.h"
int cksum_main(int argc, char **argv)
{
2006-09-17 21:58:10 +05:30
uint32_t *crc32_table = crc32_filltable(1);
2006-04-19 02:27:28 +05:30
FILE *fp;
uint32_t crc;
long length, filesize;
int bytes_read;
char *cp;
2006-04-19 02:27:28 +05:30
int inp_stdin = (argc == optind) ? 1 : 0;
2006-04-19 02:27:28 +05:30
do {
fp = bb_wfopen_input((inp_stdin) ? bb_msg_standard_input : *++argv);
2006-04-19 02:27:28 +05:30
crc = 0;
length = 0;
while ((bytes_read = fread(bb_common_bufsiz1, 1, BUFSIZ, fp)) > 0) {
cp = bb_common_bufsiz1;
2006-04-19 02:27:28 +05:30
length += bytes_read;
while (bytes_read--)
crc = (crc << 8) ^ crc32_table[((crc >> 24) ^ (*cp++)) & 0xffL];
}
2006-04-19 02:27:28 +05:30
filesize = length;
2006-04-19 02:27:28 +05:30
for (; length; length >>= 8)
crc = (crc << 8) ^ crc32_table[((crc >> 24) ^ length) & 0xffL];
crc ^= 0xffffffffL;
if (inp_stdin) {
bb_printf("%" PRIu32 " %li\n", crc, filesize);
2006-04-19 02:27:28 +05:30
break;
}
bb_printf("%" PRIu32 " %li %s\n", crc, filesize, *argv);
2006-04-19 02:27:28 +05:30
fclose(fp);
} while (*(argv + 1));
2006-04-19 02:27:28 +05:30
return EXIT_SUCCESS;
}