1/*
2 * Copyright (C) 2007 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17//
18// Miscellaneous zip/gzip utility functions.
19//
20#ifndef __LIBS_ZIPUTILS_H
21#define __LIBS_ZIPUTILS_H
22
23#include <stdio.h>
24#include <time.h>
25
26namespace android {
27
28/*
29 * Container class for utility functions, primarily for namespace reasons.
30 */
31class ZipUtils {
32public:
33    /*
34     * General utility function for uncompressing "deflate" data from a file
35     * to a buffer.
36     */
37    static bool inflateToBuffer(FILE* fp, void* buf, long uncompressedLen,
38        long compressedLen);
39    static bool inflateToBuffer(int fd, void* buf, long uncompressedLen,
40        long compressedLen);
41    static bool inflateToBuffer(void *in, void* buf, long uncompressedLen,
42        long compressedLen);
43
44    /*
45     * Someday we might want to make this generic and handle bzip2 ".bz2"
46     * files too.
47     *
48     * We could declare gzip to be a sub-class of zip that has exactly
49     * one always-compressed entry, but we currently want to treat Zip
50     * and gzip as distinct, so there's no value.
51     *
52     * The zlib library has some gzip utilities, but it has no interface
53     * for extracting the uncompressed length of the file (you do *not*
54     * want to gzseek to the end).
55     *
56     * Pass in a seeked file pointer for the gzip file.  If this is a gzip
57     * file, we set our return values appropriately and return "true" with
58     * the file seeked to the start of the compressed data.
59     */
60    static bool examineGzip(FILE* fp, int* pCompressionMethod,
61        long* pUncompressedLen, long* pCompressedLen, unsigned long* pCRC32);
62
63    /*
64     * Utility function to convert ZIP's time format to a timespec struct.
65     */
66    static inline void zipTimeToTimespec(long when, struct tm* timespec) {
67        const long date = when >> 16;
68        timespec->tm_year = ((date >> 9) & 0x7F) + 80; // Zip is years since 1980
69        timespec->tm_mon = (date >> 5) & 0x0F;
70        timespec->tm_mday = date & 0x1F;
71
72        timespec->tm_hour = (when >> 11) & 0x1F;
73        timespec->tm_min = (when >> 5) & 0x3F;
74        timespec->tm_sec = (when & 0x1F) << 1;
75    }
76private:
77    ZipUtils() {}
78    ~ZipUtils() {}
79};
80
81}; // namespace android
82
83#endif /*__LIBS_ZIPUTILS_H*/
84