| /* 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; |
| RESERVE_CONFIG_BUFFER(buf, BUFSIZ); |
| int inp_stdin = (argc == optind) ? 1 : 0; |
| |
| do { |
| fp = bb_wfopen_input((inp_stdin) ? bb_msg_standard_input : *++argv); |
| |
| crc = 0; |
| length = 0; |
| |
| while ((bytes_read = fread(buf, 1, BUFSIZ, fp)) > 0) { |
| cp = buf; |
| 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)); |
| |
| return EXIT_SUCCESS; |
| } |