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1 | /* vi: set sw=4 ts=4: */
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2 | /*
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3 | * cksum - calculate the CRC32 checksum of a file
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4 | *
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5 | * Copyright (C) 2006 by Rob Sullivan, with ideas from code by Walter Harms
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6 | *
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7 | * Licensed under GPLv2 or later, see file LICENSE in this tarball for details. */
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8 |
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9 | #include "libbb.h"
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10 |
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11 | int cksum_main(int argc, char **argv);
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12 | int cksum_main(int argc, char **argv)
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13 | {
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14 | uint32_t *crc32_table = crc32_filltable(NULL, 1);
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15 |
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16 | FILE *fp;
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17 | uint32_t crc;
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18 | long length, filesize;
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19 | int bytes_read;
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20 | char *cp;
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21 |
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22 | int inp_stdin = (argc == optind) ? 1 : 0;
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23 |
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24 | do {
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25 | fp = fopen_or_warn_stdin((inp_stdin) ? bb_msg_standard_input : *++argv);
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26 |
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27 | crc = 0;
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28 | length = 0;
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29 |
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30 | #define read_buf bb_common_bufsiz1
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31 | while ((bytes_read = fread(read_buf, 1, BUFSIZ, fp)) > 0) {
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32 | cp = read_buf;
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33 | length += bytes_read;
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34 | while (bytes_read--)
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35 | crc = (crc << 8) ^ crc32_table[((crc >> 24) ^ (*cp++)) & 0xffL];
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36 | }
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37 |
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38 | filesize = length;
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39 |
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40 | for (; length; length >>= 8)
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41 | crc = (crc << 8) ^ crc32_table[((crc >> 24) ^ length) & 0xffL];
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42 | crc ^= 0xffffffffL;
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43 |
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44 | if (inp_stdin) {
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45 | printf("%" PRIu32 " %li\n", crc, filesize);
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46 | break;
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47 | }
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48 |
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49 | printf("%" PRIu32 " %li %s\n", crc, filesize, *argv);
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50 | fclose(fp);
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51 | } while (*(argv + 1));
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52 |
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53 | fflush_stdout_and_exit(EXIT_SUCCESS);
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54 | }
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