busybox/coreutils/cksum.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 tarball for details.
 */
#include "libbb.h"

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;
	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) {
			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) {
			cp = (uint8_t *) read_buf;
			length += bytes_read;
			do {
				crc = (crc << 8) ^ crc32_table[(crc >> 24) ^ *cp++];
			} while (--bytes_read);
		}
		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);
}
1	/* vi: set sw=4 ts=4: */
2	/*
3	* cksum - calculate the CRC32 checksum of a file
4	*
5	* Copyright (C) 2006 by Rob Sullivan, with ideas from code by Walter Harms
6	*
7	* Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
8	*/
9	#include "libbb.h"
10
11	int cksum_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
12	int cksum_main(int argc UNUSED_PARAM, char **argv)
13	{
14	uint32_t *crc32_table = crc32_filltable(NULL, 1);
15	uint32_t crc;
16	off_t length, filesize;
17	int bytes_read;
18	int exit_code = EXIT_SUCCESS;
19	uint8_t *cp;
20
21	#if ENABLE_DESKTOP
22	getopt32(argv, ""); /* coreutils 6.9 compat */
23	argv += optind;
24	#else
25	argv++;
26	#endif
27
28	do {
29	int fd = open_or_warn_stdin(argv ? argv : bb_msg_standard_input);
30
31	if (fd < 0) {
32	exit_code = EXIT_FAILURE;
33	continue;
34	}
35	crc = 0;
36	length = 0;
37
38	#define read_buf bb_common_bufsiz1
39	while ((bytes_read = safe_read(fd, read_buf, sizeof(read_buf))) > 0) {
40	cp = (uint8_t *) read_buf;
41	length += bytes_read;
42	do {
43	crc = (crc << 8) ^ crc32_table[(crc >> 24) ^ *cp++];
44	} while (--bytes_read);
45	}
46	close(fd);
47
48	filesize = length;
49
50	while (length) {
51	crc = (crc << 8) ^ crc32_table[(uint8_t)(crc >> 24) ^ (uint8_t)length];
52	/* must ensure that shift is unsigned! */
53	if (sizeof(length) <= sizeof(unsigned))
54	length = (unsigned)length >> 8;
55	else if (sizeof(length) <= sizeof(unsigned long))
56	length = (unsigned long)length >> 8;
57	else
58	length = (unsigned long long)length >> 8;
59	}
60	crc = ~crc;
61
62	printf((*argv ? "%"PRIu32" %"OFF_FMT"i %s\n" : "%"PRIu32" %"OFF_FMT"i\n"),
63	crc, filesize, *argv);
64	} while (argv && ++argv);
65
66	fflush_stdout_and_exit(exit_code);
67	}