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 <stdint.h>
24#include <string.h>
25#include <stdio.h>
26#include <time.h>
27
28namespace android {
29
30/*
31 * Container class for utility functions, primarily for namespace reasons.
32 */
33class ZipUtils {
34public:
35    /*
36     * General utility function for uncompressing "deflate" data from a file
37     * to a buffer.
38     */
39    static bool inflateToBuffer(FILE* fp, void* buf, long uncompressedLen,
40        long compressedLen);
41    static bool inflateToBuffer(int fd, void* buf, long uncompressedLen,
42        long compressedLen);
43    static bool inflateToBuffer(void *in, void* buf, long uncompressedLen,
44        long compressedLen);
45
46    /*
47     * Someday we might want to make this generic and handle bzip2 ".bz2"
48     * files too.
49     *
50     * We could declare gzip to be a sub-class of zip that has exactly
51     * one always-compressed entry, but we currently want to treat Zip
52     * and gzip as distinct, so there's no value.
53     *
54     * The zlib library has some gzip utilities, but it has no interface
55     * for extracting the uncompressed length of the file (you do *not*
56     * want to gzseek to the end).
57     *
58     * Pass in a seeked file pointer for the gzip file.  If this is a gzip
59     * file, we set our return values appropriately and return "true" with
60     * the file seeked to the start of the compressed data.
61     */
62    static bool examineGzip(FILE* fp, int* pCompressionMethod,
63        long* pUncompressedLen, long* pCompressedLen, unsigned long* pCRC32);
64
65    /*
66     * Utility function to convert ZIP's time format to a timespec struct.
67     *
68     * NOTE: this method will clear all existing state from |timespec|.
69     */
70    static inline void zipTimeToTimespec(uint32_t when, struct tm* timespec) {
71        const uint32_t date = when >> 16;
72
73        memset(timespec, 0, sizeof(struct tm));
74        timespec->tm_year = ((date >> 9) & 0x7F) + 80; // Zip is years since 1980
75        timespec->tm_mon = ((date >> 5) & 0x0F) - 1;
76        timespec->tm_mday = date & 0x1F;
77
78        timespec->tm_hour = (when >> 11) & 0x1F;
79        timespec->tm_min = (when >> 5) & 0x3F;
80        timespec->tm_sec = (when & 0x1F) << 1;
81        timespec->tm_isdst = -1;
82    }
83private:
84    ZipUtils() {}
85    ~ZipUtils() {}
86};
87
88}; // namespace android
89
90#endif /*__LIBS_ZIPUTILS_H*/
91