Contents of /tags/mkinitrd-6_1_2/busybox/coreutils/cksum.c
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Mon May 4 17:23:09 2009 UTC (15 years, 4 months ago) by niro
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File size: 1595 byte(s)
Mon May 4 17:23:09 2009 UTC (15 years, 4 months ago) by niro
File MIME type: text/plain
File size: 1595 byte(s)
tagged 'mkinitrd-6_1_2'
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 | uint8_t *cp; |
19 | |
20 | #if ENABLE_DESKTOP |
21 | getopt32(argv, ""); /* coreutils 6.9 compat */ |
22 | argv += optind; |
23 | #else |
24 | argv++; |
25 | #endif |
26 | |
27 | do { |
28 | int fd = open_or_warn_stdin(*argv ? *argv : bb_msg_standard_input); |
29 | |
30 | if (fd < 0) |
31 | continue; |
32 | crc = 0; |
33 | length = 0; |
34 | |
35 | #define read_buf bb_common_bufsiz1 |
36 | while ((bytes_read = safe_read(fd, read_buf, sizeof(read_buf))) > 0) { |
37 | cp = (uint8_t *) read_buf; |
38 | length += bytes_read; |
39 | do { |
40 | crc = (crc << 8) ^ crc32_table[(crc >> 24) ^ *cp++]; |
41 | } while (--bytes_read); |
42 | } |
43 | close(fd); |
44 | |
45 | filesize = length; |
46 | |
47 | while (length) { |
48 | crc = (crc << 8) ^ crc32_table[(uint8_t)(crc >> 24) ^ (uint8_t)length]; |
49 | /* must ensure that shift is unsigned! */ |
50 | if (sizeof(length) <= sizeof(unsigned)) |
51 | length = (unsigned)length >> 8; |
52 | else if (sizeof(length) <= sizeof(unsigned long)) |
53 | length = (unsigned long)length >> 8; |
54 | else |
55 | length = (unsigned long long)length >> 8; |
56 | } |
57 | crc = ~crc; |
58 | |
59 | printf((*argv ? "%"PRIu32" %"OFF_FMT"i %s\n" : "%"PRIu32" %"OFF_FMT"i\n"), |
60 | crc, filesize, *argv); |
61 | } while (*argv && *++argv); |
62 | |
63 | fflush_stdout_and_exit(EXIT_SUCCESS); |
64 | } |