96 lines
2.9 KiB
C
96 lines
2.9 KiB
C
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/*
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zip_source_seek.c -- seek to offset
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Copyright (C) 2014 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 "zipint.h"
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ZIP_EXTERN int
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zip_source_seek(zip_source_t *src, zip_int64_t offset, int whence) {
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zip_source_args_seek_t args;
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if (src->source_closed) {
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return -1;
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}
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if (!ZIP_SOURCE_IS_OPEN_READING(src) || (whence != SEEK_SET && whence != SEEK_CUR && whence != SEEK_END)) {
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zip_error_set(&src->error, ZIP_ER_INVAL, 0);
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return -1;
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}
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args.offset = offset;
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args.whence = whence;
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if (_zip_source_call(src, &args, sizeof(args), ZIP_SOURCE_SEEK) < 0) {
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return -1;
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}
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src->eof = 0;
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return 0;
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}
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zip_int64_t
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zip_source_seek_compute_offset(zip_uint64_t offset, zip_uint64_t length, void *data, zip_uint64_t data_length, zip_error_t *error) {
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zip_int64_t new_offset;
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zip_source_args_seek_t *args = ZIP_SOURCE_GET_ARGS(zip_source_args_seek_t, data, data_length, error);
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if (args == NULL) {
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return -1;
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}
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switch (args->whence) {
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case SEEK_CUR:
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new_offset = (zip_int64_t)offset + args->offset;
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break;
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case SEEK_END:
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new_offset = (zip_int64_t)length + args->offset;
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break;
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case SEEK_SET:
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new_offset = args->offset;
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break;
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default:
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zip_error_set(error, ZIP_ER_INVAL, 0);
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return -1;
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}
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if (new_offset < 0 || (zip_uint64_t)new_offset > length) {
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zip_error_set(error, ZIP_ER_INVAL, 0);
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return -1;
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}
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return new_offset;
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}
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