xref: /PHP-7.0/ext/zip/lib/zip_source_seek.c (revision 9e0cc7a1)
1 /*
2   zip_source_seek.c -- seek to offset
3   Copyright (C) 2014 Dieter Baron and Thomas Klausner
4 
5   This file is part of libzip, a library to manipulate ZIP archives.
6   The authors can be contacted at <libzip@nih.at>
7 
8   Redistribution and use in source and binary forms, with or without
9   modification, are permitted provided that the following conditions
10   are met:
11   1. Redistributions of source code must retain the above copyright
12      notice, this list of conditions and the following disclaimer.
13   2. Redistributions in binary form must reproduce the above copyright
14      notice, this list of conditions and the following disclaimer in
15      the documentation and/or other materials provided with the
16      distribution.
17   3. The names of the authors may not be used to endorse or promote
18      products derived from this software without specific prior
19      written permission.
20 
21   THIS SOFTWARE IS PROVIDED BY THE AUTHORS ``AS IS'' AND ANY EXPRESS
22   OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
23   WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24   ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY
25   DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26   DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
27   GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
28   INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER
29   IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
30   OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN
31   IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
32 */
33 
34 
35 #include "zipint.h"
36 
37 
38 ZIP_EXTERN int
zip_source_seek(zip_source_t * src,zip_int64_t offset,int whence)39 zip_source_seek(zip_source_t *src, zip_int64_t offset, int whence)
40 {
41     zip_source_args_seek_t args;
42 
43     if (src->source_closed) {
44         return -1;
45     }
46     if (!ZIP_SOURCE_IS_OPEN_READING(src) || (whence != SEEK_SET && whence != SEEK_CUR && whence != SEEK_END)) {
47         zip_error_set(&src->error, ZIP_ER_INVAL, 0);
48         return -1;
49     }
50 
51     args.offset = offset;
52     args.whence = whence;
53 
54     return (_zip_source_call(src, &args, sizeof(args), ZIP_SOURCE_SEEK) < 0 ? -1 : 0);
55 }
56 
57 
58 zip_int64_t
zip_source_seek_compute_offset(zip_uint64_t offset,zip_uint64_t length,void * data,zip_uint64_t data_length,zip_error_t * error)59 zip_source_seek_compute_offset(zip_uint64_t offset, zip_uint64_t length, void *data, zip_uint64_t data_length, zip_error_t *error)
60 {
61     zip_int64_t new_offset;
62     zip_source_args_seek_t *args = ZIP_SOURCE_GET_ARGS(zip_source_args_seek_t, data, data_length, error);
63 
64     if (args == NULL) {
65         return -1;
66     }
67 
68     switch (args->whence) {
69         case SEEK_CUR:
70             new_offset = (zip_int64_t)offset + args->offset;
71             break;
72 
73         case SEEK_END:
74             new_offset = (zip_int64_t)length + args->offset;
75             break;
76 
77         case SEEK_SET:
78             new_offset = args->offset;
79             break;
80 
81         default:
82             zip_error_set(error, ZIP_ER_INVAL, 0);
83             return -1;
84     }
85 
86     if (new_offset < 0 || (zip_uint64_t)new_offset > length) {
87         zip_error_set(error, ZIP_ER_INVAL, 0);
88         return -1;
89     }
90 
91     return new_offset;
92 }
93