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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 <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      */
     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:
     84     ZipUtils() {}
     85     ~ZipUtils() {}
     86 };
     87 
     88 }; // namespace android
     89 
     90 #endif /*__LIBS_ZIPUTILS_H*/
     91