source: branches/2.2.9/mindi-busybox/coreutils/cksum.c @ 2859

Last change on this file since 2859 was 2859, checked in by bruno, 8 years ago
  • Update to upstream busybox 1.18.5
File size: 1.6 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#include "libbb.h"
10
11/* This is a NOEXEC applet. Be very careful! */
12
13int cksum_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
14int cksum_main(int argc UNUSED_PARAM, char **argv)
15{
16    uint32_t *crc32_table = crc32_filltable(NULL, 1);
17    uint32_t crc;
18    off_t length, filesize;
19    int bytes_read;
20    int exit_code = EXIT_SUCCESS;
21
22#if ENABLE_DESKTOP
23    getopt32(argv, ""); /* coreutils 6.9 compat */
24    argv += optind;
25#else
26    argv++;
27#endif
28
29    do {
30        int fd = open_or_warn_stdin(*argv ? *argv : bb_msg_standard_input);
31
32        if (fd < 0) {
33            exit_code = EXIT_FAILURE;
34            continue;
35        }
36        crc = 0;
37        length = 0;
38
39#define read_buf bb_common_bufsiz1
40        while ((bytes_read = safe_read(fd, read_buf, sizeof(read_buf))) > 0) {
41            length += bytes_read;
42            crc = crc32_block_endian1(crc, read_buf, bytes_read, crc32_table);
43        }
44        close(fd);
45
46        filesize = length;
47
48        while (length) {
49            crc = (crc << 8) ^ crc32_table[(uint8_t)(crc >> 24) ^ (uint8_t)length];
50            /* must ensure that shift is unsigned! */
51            if (sizeof(length) <= sizeof(unsigned))
52                length = (unsigned)length >> 8;
53            else if (sizeof(length) <= sizeof(unsigned long))
54                length = (unsigned long)length >> 8;
55            else
56                length = (unsigned long long)length >> 8;
57        }
58        crc = ~crc;
59
60        printf((*argv ? "%"PRIu32" %"OFF_FMT"i %s\n" : "%"PRIu32" %"OFF_FMT"i\n"),
61                crc, filesize, *argv);
62    } while (*argv && *++argv);
63
64    fflush_stdout_and_exit(exit_code);
65}
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