aboutsummaryrefslogtreecommitdiff
path: root/coreutils/cksum.c
diff options
context:
space:
mode:
Diffstat (limited to 'coreutils/cksum.c')
-rw-r--r--coreutils/cksum.c53
1 files changed, 53 insertions, 0 deletions
diff --git a/coreutils/cksum.c b/coreutils/cksum.c
new file mode 100644
index 000000000..52213328c
--- /dev/null
+++ b/coreutils/cksum.c
@@ -0,0 +1,53 @@
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 "busybox.h"
10
11int cksum_main(int argc, char **argv)
12{
13
14 uint32_t *crc32_table = crc32_filltable(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 while ((bytes_read = fread(bb_common_bufsiz1, 1, BUFSIZ, fp)) > 0) {
31 cp = bb_common_bufsiz1;
32 length += bytes_read;
33 while (bytes_read--)
34 crc = (crc << 8) ^ crc32_table[((crc >> 24) ^ (*cp++)) & 0xffL];
35 }
36
37 filesize = length;
38
39 for (; length; length >>= 8)
40 crc = (crc << 8) ^ crc32_table[((crc >> 24) ^ length) & 0xffL];
41 crc ^= 0xffffffffL;
42
43 if (inp_stdin) {
44 printf("%" PRIu32 " %li\n", crc, filesize);
45 break;
46 }
47
48 printf("%" PRIu32 " %li %s\n", crc, filesize, *argv);
49 fclose(fp);
50 } while (*(argv + 1));
51
52 fflush_stdout_and_exit(EXIT_SUCCESS);
53}