busybox/coreutils/cksum.c
Denys Vlasenko 9ce642f974 libbb: introduce and use common crc32 routine
function                                             old     new   delta
crc32_block_endian1                                    -      37     +37
crc32_block_endian0                                    -      34     +34
global_crc32_table                                     -       8      +8
file_read                                             82      87      +5
gzip_main                                            211     214      +3
xz_crc32                                              40      35      -5
crc32_table                                            8       -      -8
calculate_gunzip_crc                                  54      34     -20
lzo_crc32                                             54      25     -29
cksum_main                                           298     211     -87
------------------------------------------------------------------------------
(add/remove: 3/1 grow/shrink: 2/4 up/down: 87/-149)           Total: -62 bytes

Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com>
2010-10-27 15:26:45 +02:00

65 lines
1.6 KiB
C

/* 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 source tree.
*/
#include "libbb.h"
/* This is a NOEXEC applet. Be very careful! */
int cksum_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int cksum_main(int argc UNUSED_PARAM, char **argv)
{
uint32_t *crc32_table = crc32_filltable(NULL, 1);
uint32_t crc;
off_t length, filesize;
int bytes_read;
int exit_code = EXIT_SUCCESS;
#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) {
exit_code = EXIT_FAILURE;
continue;
}
crc = 0;
length = 0;
#define read_buf bb_common_bufsiz1
while ((bytes_read = safe_read(fd, read_buf, sizeof(read_buf))) > 0) {
crc = crc32_block_endian1(crc, read_buf, bytes_read, crc32_table);
}
close(fd);
filesize = length;
while (length) {
crc = (crc << 8) ^ crc32_table[(uint8_t)(crc >> 24) ^ (uint8_t)length];
/* must ensure that shift is unsigned! */
if (sizeof(length) <= sizeof(unsigned))
length = (unsigned)length >> 8;
else if (sizeof(length) <= sizeof(unsigned long))
length = (unsigned long)length >> 8;
else
length = (unsigned long long)length >> 8;
}
crc = ~crc;
printf((*argv ? "%"PRIu32" %"OFF_FMT"i %s\n" : "%"PRIu32" %"OFF_FMT"i\n"),
crc, filesize, *argv);
} while (*argv && *++argv);
fflush_stdout_and_exit(exit_code);
}