57 lines
1.3 KiB
C
57 lines
1.3 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) MAIN_EXTERNALLY_VISIBLE;
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int cksum_main(int argc UNUSED_PARAM, char **argv)
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{
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uint32_t *crc32_table = crc32_filltable(NULL, 1);
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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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uint8_t *cp;
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#if ENABLE_DESKTOP
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getopt32(argv, ""); /* coreutils 6.9 compat */
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argv += optind;
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#else
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argv++;
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#endif
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do {
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int fd = open_or_warn_stdin(*argv ? *argv : bb_msg_standard_input);
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if (fd < 0)
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continue;
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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 = safe_read(fd, read_buf, sizeof(read_buf))) > 0) {
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cp = (uint8_t *) read_buf;
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length += bytes_read;
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do {
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crc = (crc << 8) ^ crc32_table[(crc >> 24) ^ *cp++];
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} while (--bytes_read);
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}
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close(fd);
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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) & 0xff];
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crc ^= 0xffffffffL;
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printf((*argv ? "%" PRIu32 " %li %s\n" : "%" PRIu32 " %li\n"),
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crc, filesize, *argv);
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} while (*argv && *++argv);
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fflush_stdout_and_exit(EXIT_SUCCESS);
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}
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