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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 
     25 namespace android {
     26 
     27 /*
     28  * Container class for utility functions, primarily for namespace reasons.
     29  */
     30 class ZipUtils {
     31 public:
     32     /*
     33      * General utility function for uncompressing "deflate" data from a file
     34      * to a buffer.
     35      */
     36     static bool inflateToBuffer(int fd, void* buf, long uncompressedLen,
     37         long compressedLen);
     38     static bool inflateToBuffer(FILE* fp, void* buf, long uncompressedLen,
     39         long compressedLen);
     40 
     41     /*
     42      * Someday we might want to make this generic and handle bzip2 ".bz2"
     43      * files too.
     44      *
     45      * We could declare gzip to be a sub-class of zip that has exactly
     46      * one always-compressed entry, but we currently want to treat Zip
     47      * and gzip as distinct, so there's no value.
     48      *
     49      * The zlib library has some gzip utilities, but it has no interface
     50      * for extracting the uncompressed length of the file (you do *not*
     51      * want to gzseek to the end).
     52      *
     53      * Pass in a seeked file pointer for the gzip file.  If this is a gzip
     54      * file, we set our return values appropriately and return "true" with
     55      * the file seeked to the start of the compressed data.
     56      */
     57     static bool examineGzip(FILE* fp, int* pCompressionMethod,
     58         long* pUncompressedLen, long* pCompressedLen, unsigned long* pCRC32);
     59 
     60 private:
     61     ZipUtils() {}
     62     ~ZipUtils() {}
     63 };
     64 
     65 }; // namespace android
     66 
     67 #endif /*__LIBS_ZIPUTILS_H*/
     68