1 /* vi: set sw=4 ts=4: */
3 * cksum - calculate the CRC32 checksum of a file
5 * Copyright (C) 2006 by Rob Sullivan, with ideas from code by Walter Harms
7 * Licensed under GPLv2 or later, see file LICENSE in this tarball for details. */
11 int cksum_main(int argc, char **argv);
12 int cksum_main(int argc, char **argv)
15 uint32_t *crc32_table = crc32_filltable(1);
19 long length, filesize;
23 int inp_stdin = (argc == optind) ? 1 : 0;
26 fp = fopen_or_warn_stdin((inp_stdin) ? bb_msg_standard_input : *++argv);
31 while ((bytes_read = fread(bb_common_bufsiz1, 1, BUFSIZ, fp)) > 0) {
32 cp = bb_common_bufsiz1;
35 crc = (crc << 8) ^ crc32_table[((crc >> 24) ^ (*cp++)) & 0xffL];
40 for (; length; length >>= 8)
41 crc = (crc << 8) ^ crc32_table[((crc >> 24) ^ length) & 0xffL];
45 printf("%" PRIu32 " %li\n", crc, filesize);
49 printf("%" PRIu32 " %li %s\n", crc, filesize, *argv);
51 } while (*(argv + 1));
53 fflush_stdout_and_exit(EXIT_SUCCESS);