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
11int cksum_main(int argc, char **argv);
12int cksum_main(int argc, char **argv)
13{
14	uint32_t *crc32_table = crc32_filltable(NULL, 1);
15
16	FILE *fp;
17	uint32_t crc;
18	long length, filesize;
19	int bytes_read;
20	char *cp;
21
22	int inp_stdin = (argc == optind) ? 1 : 0;
23
24	do {
25		fp = fopen_or_warn_stdin((inp_stdin) ? bb_msg_standard_input : *++argv);
26
27		crc = 0;
28		length = 0;
29
30#define read_buf bb_common_bufsiz1
31		while ((bytes_read = fread(read_buf, 1, BUFSIZ, fp)) > 0) {
32			cp = read_buf;
33			length += bytes_read;
34			while (bytes_read--)
35				crc = (crc << 8) ^ crc32_table[((crc >> 24) ^ (*cp++)) & 0xffL];
36		}
37
38		filesize = length;
39
40		for (; length; length >>= 8)
41			crc = (crc << 8) ^ crc32_table[((crc >> 24) ^ length) & 0xffL];
42		crc ^= 0xffffffffL;
43
44		if (inp_stdin) {
45			printf("%" PRIu32 " %li\n", crc, filesize);
46			break;
47		}
48
49		printf("%" PRIu32 " %li %s\n", crc, filesize, *argv);
50		fclose(fp);
51	} while (*(argv + 1));
52
53	fflush_stdout_and_exit(EXIT_SUCCESS);
54}
55