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 
28 namespace android {
29 
30 /*
31  * Container class for utility functions, primarily for namespace reasons.
32  */
33 class ZipUtils {
34 public:
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(const 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      */
zipTimeToTimespec(uint32_t when,struct tm * timespec)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     }
83 private:
ZipUtils()84     ZipUtils() {}
~ZipUtils()85     ~ZipUtils() {}
86 };
87 
88 }; // namespace android
89 
90 #endif /*__LIBS_ZIPUTILS_H*/
91