source: branches/3.2/mindi-busybox/coreutils/cksum.c @ 3232

Last change on this file since 3232 was 3232, checked in by bruno, 6 years ago
  • Update mindi-busybox to 1.21.1
File size: 1.8 KB
Line 
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 source tree.
8 */
9
10//usage:#define cksum_trivial_usage
11//usage:       "FILES..."
12//usage:#define cksum_full_usage "\n\n"
13//usage:       "Calculate the CRC32 checksums of FILES"
14
15#include "libbb.h"
16
17/* This is a NOEXEC applet. Be very careful! */
18
19int cksum_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
20int cksum_main(int argc UNUSED_PARAM, char **argv)
21{
22    uint32_t *crc32_table = crc32_filltable(NULL, 1);
23    uint32_t crc;
24    off_t length, filesize;
25    int bytes_read;
26    int exit_code = EXIT_SUCCESS;
27
28#if ENABLE_DESKTOP
29    getopt32(argv, ""); /* coreutils 6.9 compat */
30    argv += optind;
31#else
32    argv++;
33#endif
34
35    do {
36        int fd = open_or_warn_stdin(*argv ? *argv : bb_msg_standard_input);
37
38        if (fd < 0) {
39            exit_code = EXIT_FAILURE;
40            continue;
41        }
42        crc = 0;
43        length = 0;
44
45#define read_buf bb_common_bufsiz1
46        while ((bytes_read = safe_read(fd, read_buf, sizeof(read_buf))) > 0) {
47            length += bytes_read;
48            crc = crc32_block_endian1(crc, read_buf, bytes_read, crc32_table);
49        }
50        close(fd);
51
52        filesize = length;
53
54        while (length) {
55            crc = (crc << 8) ^ crc32_table[(uint8_t)(crc >> 24) ^ (uint8_t)length];
56            /* must ensure that shift is unsigned! */
57            if (sizeof(length) <= sizeof(unsigned))
58                length = (unsigned)length >> 8;
59            else if (sizeof(length) <= sizeof(unsigned long))
60                length = (unsigned long)length >> 8;
61            else
62                length = (unsigned long long)length >> 8;
63        }
64        crc = ~crc;
65
66        printf((*argv ? "%"PRIu32" %"OFF_FMT"i %s\n" : "%"PRIu32" %"OFF_FMT"i\n"),
67                crc, filesize, *argv);
68    } while (*argv && *++argv);
69
70    fflush_stdout_and_exit(exit_code);
71}
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