1 /*
2  * Copyright (C) 2010 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 #ifndef ANDROID_ASSET_MANAGER_H
19 #define ANDROID_ASSET_MANAGER_H
20 
21 #include <sys/types.h>
22 
23 #ifdef __cplusplus
24 extern "C" {
25 #endif
26 
27 struct AAssetManager;
28 typedef struct AAssetManager AAssetManager;
29 
30 struct AAssetDir;
31 typedef struct AAssetDir AAssetDir;
32 
33 struct AAsset;
34 typedef struct AAsset AAsset;
35 
36 /* Available modes for opening assets */
37 enum {
38     AASSET_MODE_UNKNOWN      = 0,
39     AASSET_MODE_RANDOM       = 1,
40     AASSET_MODE_STREAMING    = 2,
41     AASSET_MODE_BUFFER       = 3
42 };
43 
44 
45 /**
46  * Open the named directory within the asset hierarchy.  The directory can then
47  * be inspected with the AAssetDir functions.  To open the top-level directory,
48  * pass in "" as the dirName.
49  *
50  * The object returned here should be freed by calling AAssetDir_close().
51  */
52 AAssetDir* AAssetManager_openDir(AAssetManager* mgr, const char* dirName);
53 
54 /**
55  * Open an asset.
56  *
57  * The object returned here should be freed by calling AAsset_close().
58  */
59 AAsset* AAssetManager_open(AAssetManager* mgr, const char* filename, int mode);
60 
61 /**
62  * Iterate over the files in an asset directory.  A NULL string is returned
63  * when all the file names have been returned.
64  *
65  * The returned file name is suitable for passing to AAssetManager_open().
66  *
67  * The string returned here is owned by the AssetDir implementation and is not
68  * guaranteed to remain valid if any other calls are made on this AAssetDir
69  * instance.
70  */
71 const char* AAssetDir_getNextFileName(AAssetDir* assetDir);
72 
73 /**
74  * Reset the iteration state of AAssetDir_getNextFileName() to the beginning.
75  */
76 void AAssetDir_rewind(AAssetDir* assetDir);
77 
78 /**
79  * Close an opened AAssetDir, freeing any related resources.
80  */
81 void AAssetDir_close(AAssetDir* assetDir);
82 
83 /**
84  * Attempt to read 'count' bytes of data from the current offset.
85  *
86  * Returns the number of bytes read, zero on EOF, or < 0 on error.
87  */
88 int AAsset_read(AAsset* asset, void* buf, size_t count);
89 
90 /**
91  * Seek to the specified offset within the asset data.  'whence' uses the
92  * same constants as lseek()/fseek().
93  *
94  * Returns the new position on success, or (off_t) -1 on error.
95  */
96 off_t AAsset_seek(AAsset* asset, off_t offset, int whence);
97 
98 /**
99  * Close the asset, freeing all associated resources.
100  */
101 void AAsset_close(AAsset* asset);
102 
103 /**
104  * Get a pointer to a buffer holding the entire contents of the assset.
105  *
106  * Returns NULL on failure.
107  */
108 const void* AAsset_getBuffer(AAsset* asset);
109 
110 /**
111  * Report the total size of the asset data.
112  */
113 off_t AAsset_getLength(AAsset* asset);
114 
115 /**
116  * Report the total amount of asset data that can be read from the current position.
117  */
118 off_t AAsset_getRemainingLength(AAsset* asset);
119 
120 /**
121  * Open a new file descriptor that can be used to read the asset data.
122  *
123  * Returns < 0 if direct fd access is not possible (for example, if the asset is
124  * compressed).
125  */
126 int AAsset_openFileDescriptor(AAsset* asset, off_t* outStart, off_t* outLength);
127 
128 /**
129  * Returns whether this asset's internal buffer is allocated in ordinary RAM (i.e. not
130  * mmapped).
131  */
132 int AAsset_isAllocated(AAsset* asset);
133 
134 
135 
136 #ifdef __cplusplus
137 };
138 #endif
139 
140 #endif      // ANDROID_ASSET_MANAGER_H
141