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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 
26 namespace android {
27 
28 /*
29  * Container class for utility functions, primarily for namespace reasons.
30  */
31 class ZipUtils {
32 public:
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      */
zipTimeToTimespec(long when,struct tm * timespec)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     }
76 private:
ZipUtils()77     ZipUtils() {}
~ZipUtils()78     ~ZipUtils() {}
79 };
80 
81 }; // namespace android
82 
83 #endif /*__LIBS_ZIPUTILS_H*/
84