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 11int cksum_main(int argc, char **argv); 12int cksum_main(int argc, char **argv) 13{ 14 uint32_t *crc32_table = crc32_filltable(NULL, 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#define read_buf bb_common_bufsiz1 31 while ((bytes_read = fread(read_buf, 1, BUFSIZ, fp)) > 0) { 32 cp = read_buf; 33 length += bytes_read; 34 while (bytes_read--) 35 crc = (crc << 8) ^ crc32_table[((crc >> 24) ^ (*cp++)) & 0xffL]; 36 } 37 38 filesize = length; 39 40 for (; length; length >>= 8) 41 crc = (crc << 8) ^ crc32_table[((crc >> 24) ^ length) & 0xffL]; 42 crc ^= 0xffffffffL; 43 44 if (inp_stdin) { 45 printf("%" PRIu32 " %li\n", crc, filesize); 46 break; 47 } 48 49 printf("%" PRIu32 " %li %s\n", crc, filesize, *argv); 50 fclose(fp); 51 } while (*(argv + 1)); 52 53 fflush_stdout_and_exit(EXIT_SUCCESS); 54} 55