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      1 /*
      2  * Copyright (C) 2006 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 #ifndef UTILS_DEFINED
     18 #define UTILS_DEFINED
     19 
     20 #include "SkStream.h"
     21 
     22 #include "android_util_Binder.h"
     23 
     24 #include <jni.h>
     25 #include <androidfw/Asset.h>
     26 
     27 namespace android {
     28 
     29 class AssetStreamAdaptor : public SkStreamRewindable {
     30 public:
     31     // Enum passed to constructor. If set to kYes_OwnAsset,
     32     // the passed in Asset will be deleted upon destruction.
     33     enum OwnAsset {
     34         kYes_OwnAsset,
     35         kNo_OwnAsset,
     36     };
     37 
     38     // Enum passed to constructor. If set to kYes_HasMemoryBase,
     39     // getMemoryBase will return the Asset's buffer.
     40     enum HasMemoryBase {
     41         kYes_HasMemoryBase,
     42         kNo_HasMemoryBase,
     43     };
     44 
     45     AssetStreamAdaptor(Asset*, OwnAsset, HasMemoryBase);
     46     ~AssetStreamAdaptor();
     47 
     48     virtual bool rewind();
     49     virtual size_t read(void* buffer, size_t size);
     50     virtual bool hasLength() const { return true; }
     51     virtual size_t getLength() const;
     52     virtual bool isAtEnd() const;
     53 
     54     virtual const void* getMemoryBase() { return fMemoryBase; }
     55 
     56     virtual SkStreamRewindable* duplicate() const;
     57 private:
     58     Asset*              fAsset;
     59     const void* const   fMemoryBase;
     60     const OwnAsset      fOwnAsset;
     61 };
     62 
     63 /**
     64  *  Make a deep copy of the asset, and return it as a stream, or NULL if there
     65  *  was an error.
     66  *  FIXME: If we could "ref/reopen" the asset, we may not need to copy it here.
     67  */
     68 
     69 SkMemoryStream* CopyAssetToStream(Asset*);
     70 
     71 /** Restore the file descriptor's offset in our destructor
     72  */
     73 class AutoFDSeek {
     74 public:
     75     AutoFDSeek(int fd) : fFD(fd) {
     76         fCurr = ::lseek(fd, 0, SEEK_CUR);
     77     }
     78     ~AutoFDSeek() {
     79         if (fCurr >= 0) {
     80             ::lseek(fFD, fCurr, SEEK_SET);
     81         }
     82     }
     83 private:
     84     int     fFD;
     85     off64_t   fCurr;
     86 };
     87 
     88 jobject nullObjectReturn(const char msg[]);
     89 
     90 }; // namespace android
     91 
     92 #endif
     93