diff options
Diffstat (limited to 'coreutils/cksum.c')
-rw-r--r-- | coreutils/cksum.c | 53 |
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 @@ +/* vi: set sw=4 ts=4: */ +/* + * cksum - calculate the CRC32 checksum of a file + * + * Copyright (C) 2006 by Rob Sullivan, with ideas from code by Walter Harms + * + * Licensed under GPLv2 or later, see file LICENSE in this tarball for details. */ + +#include "busybox.h" + +int cksum_main(int argc, char **argv) +{ + + uint32_t *crc32_table = crc32_filltable(1); + + FILE *fp; + uint32_t crc; + long length, filesize; + int bytes_read; + char *cp; + + int inp_stdin = (argc == optind) ? 1 : 0; + + do { + fp = fopen_or_warn_stdin((inp_stdin) ? bb_msg_standard_input : *++argv); + + crc = 0; + length = 0; + + while ((bytes_read = fread(bb_common_bufsiz1, 1, BUFSIZ, fp)) > 0) { + cp = bb_common_bufsiz1; + length += bytes_read; + while (bytes_read--) + crc = (crc << 8) ^ crc32_table[((crc >> 24) ^ (*cp++)) & 0xffL]; + } + + filesize = length; + + for (; length; length >>= 8) + crc = (crc << 8) ^ crc32_table[((crc >> 24) ^ length) & 0xffL]; + crc ^= 0xffffffffL; + + if (inp_stdin) { + printf("%" PRIu32 " %li\n", crc, filesize); + break; + } + + printf("%" PRIu32 " %li %s\n", crc, filesize, *argv); + fclose(fp); + } while (*(argv + 1)); + + fflush_stdout_and_exit(EXIT_SUCCESS); +} |