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