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/* 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
*
* Licensed under GPLv2 or later, see file LICENSE in this tarball for details. */
#include "libbb.h"
int cksum_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int cksum_main(int argc ATTRIBUTE_UNUSED, char **argv)
{
uint32_t *crc32_table = crc32_filltable(NULL, 1);
uint32_t crc;
long length, filesize;
int bytes_read;
uint8_t *cp;
#if ENABLE_DESKTOP
getopt32(argv, ""); /* coreutils 6.9 compat */
argv += optind;
#else
argv++;
#endif
do {
int fd = open_or_warn_stdin(*argv ? *argv : bb_msg_standard_input);
if (fd < 0)
continue;
crc = 0;
length = 0;
#define read_buf bb_common_bufsiz1
while ((bytes_read = safe_read(fd, read_buf, sizeof(read_buf))) > 0) {
cp = (uint8_t *) read_buf;
length += bytes_read;
do {
crc = (crc << 8) ^ crc32_table[(crc >> 24) ^ *cp++];
} while (--bytes_read);
}
close(fd);
filesize = length;
for (; length; length >>= 8)
crc = (crc << 8) ^ crc32_table[((crc >> 24) ^ length) & 0xff];
crc ^= 0xffffffffL;
printf((*argv ? "%" PRIu32 " %li %s\n" : "%" PRIu32 " %li\n"),
crc, filesize, *argv);
} while (*argv && *++argv);
fflush_stdout_and_exit(EXIT_SUCCESS);
}
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