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