85 lines
2.6 KiB
C
85 lines
2.6 KiB
C
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/*
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zip_filerange_crc.c -- compute CRC32 for a range of a file
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Copyright (C) 2008-2016 Dieter Baron and Thomas Klausner
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This file is part of libzip, a library to manipulate ZIP archives.
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The authors can be contacted at <libzip@nih.at>
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Redistribution and use in source and binary forms, with or without
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modification, are permitted provided that the following conditions
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are met:
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1. Redistributions of source code must retain the above copyright
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notice, this list of conditions and the following disclaimer.
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2. Redistributions in binary form must reproduce the above copyright
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notice, this list of conditions and the following disclaimer in
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the documentation and/or other materials provided with the
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distribution.
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3. The names of the authors may not be used to endorse or promote
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products derived from this software without specific prior
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written permission.
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THIS SOFTWARE IS PROVIDED BY THE AUTHORS ``AS IS'' AND ANY EXPRESS
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OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY
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DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
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GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER
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IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
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OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN
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IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <stdio.h>
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#include "zipint.h"
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int
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_zip_filerange_crc(zip_source_t *src, zip_uint64_t start, zip_uint64_t len, uLong *crcp, zip_error_t *error) {
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DEFINE_BYTE_ARRAY(buf, BUFSIZE);
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zip_int64_t n;
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*crcp = crc32(0L, Z_NULL, 0);
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if (start > ZIP_INT64_MAX) {
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zip_error_set(error, ZIP_ER_SEEK, EFBIG);
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return -1;
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}
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if (zip_source_seek(src, (zip_int64_t)start, SEEK_SET) != 0) {
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_zip_error_set_from_source(error, src);
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return -1;
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}
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if (!byte_array_init(buf, BUFSIZE)) {
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zip_error_set(error, ZIP_ER_MEMORY, 0);
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return -1;
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}
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while (len > 0) {
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n = (zip_int64_t)(len > BUFSIZE ? BUFSIZE : len);
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if ((n = zip_source_read(src, buf, (zip_uint64_t)n)) < 0) {
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_zip_error_set_from_source(error, src);
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byte_array_fini(buf);
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return -1;
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}
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if (n == 0) {
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zip_error_set(error, ZIP_ER_EOF, 0);
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byte_array_fini(buf);
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return -1;
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}
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*crcp = crc32(*crcp, buf, (uInt)n);
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len -= (zip_uint64_t)n;
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}
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byte_array_fini(buf);
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return 0;
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}
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