asset_manager.h revision e1c61d3cc8458ce9a15d8109f728e60f5248939d 
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#ifdef __cplusplus
22extern "C" {
23#endif
24
25struct AAssetManager;
26typedef struct AAssetManager AAssetManager;
27
28struct AAssetDir;
29typedef struct AAssetDir AAssetDir;
30
31struct AAsset;
32typedef struct AAsset AAsset;
33
34/* Available modes for opening assets */
35enum {
36    AASSET_MODE_UNKNOWN      = 0,
37    AASSET_MODE_RANDOM       = 1,
38    AASSET_MODE_STREAMING    = 2,
39    AASSET_MODE_BUFFER       = 3
40};
41
42
43/**
44 * Open the named directory within the asset hierarchy.  The directory can then
45 * be inspected with the AAssetDir functions.  To open the top-level directory,
46 * pass in "" as the dirName.
47 *
48 * The object returned here should be freed by calling AAssetDir_close().
49 */
50AAssetDir* AAssetManager_openDir(AAssetManager* mgr, const char* dirName);
51
52/**
53 * Open an asset.
54 *
55 * The object returned here should be freed by calling AAsset_close().
56 */
57AAsset* AAssetManager_open(AAssetManager* mgr, const char* filename, int mode);
58
59/**
60 * Iterate over the files in an asset directory.  A NULL string is returned
61 * when all the file names have been returned.
62 *
63 * The returned file name is suitable for passing to AAssetManager_open().
64 *
65 * The string returned here is owned by the AssetDir implementation and is not
66 * guaranteed to remain valid if any other calls are made on this AAssetDir
67 * instance.
68 */
69const char* AAssetDir_getNextFileName(AAssetDir* assetDir);
70
71/**
72 * Reset the iteration state of AAssetDir_getNextFileName() to the beginning.
73 */
74void AAssetDir_rewind(AAssetDir* assetDir);
75
76/**
77 * Close an opened AAssetDir, freeing any related resources.
78 */
79void AAssetDir_close(AAssetDir* assetDir);
80
81/**
82 * Attempt to read 'count' bytes of data from the current offset.
83 *
84 * Returns the number of bytes read, zero on EOF, or < 0 on error.
85 */
86int AAsset_read(AAsset* asset, void* buf, size_t count);
87
88/**
89 * Seek to the specified offset within the asset data.  'whence' uses the
90 * same constants as lseek()/fseek().
91 *
92 * Returns the new position on success, or (off_t) -1 on error.
93 */
94off_t AAsset_seek(AAsset* asset, off_t offset, int whence);
95
96/**
97 * Seek to the specified offset within the asset data.  'whence' uses the
98 * same constants as lseek()/fseek().
99 *
100 * Uses 64-bit data type for large files as opposed to the 32-bit type used
101 * by AAsset_seek.
102 *
103 * Returns the new position on success, or (off64_t) -1 on error.
104 */
105off64_t AAsset_seek64(AAsset* asset, off64_t offset, int whence);
106
107/**
108 * Close the asset, freeing all associated resources.
109 */
110void AAsset_close(AAsset* asset);
111
112/**
113 * Get a pointer to a buffer holding the entire contents of the assset.
114 *
115 * Returns NULL on failure.
116 */
117const void* AAsset_getBuffer(AAsset* asset);
118
119/**
120 * Report the total size of the asset data.
121 */
122off_t AAsset_getLength(AAsset* asset);
123
124/**
125 * Report the total size of the asset data. Reports the size using a 64-bit
126 * number insted of 32-bit as AAsset_getLength.
127 */
128off64_t AAsset_getLength64(AAsset* asset);
129
130/**
131 * Report the total amount of asset data that can be read from the current position.
132 */
133off_t AAsset_getRemainingLength(AAsset* asset);
134
135/**
136 * Report the total amount of asset data that can be read from the current position.
137 *
138 * Uses a 64-bit number instead of a 32-bit number as AAsset_getRemainingLength does.
139 */
140off64_t AAsset_getRemainingLength64(AAsset* asset);
141
142/**
143 * Open a new file descriptor that can be used to read the asset data. If the
144 * start or length cannot be represented by a 32-bit number, it will be
145 * truncated. If the file is large, use AAsset_openFileDescriptor64 instead.
146 *
147 * Returns < 0 if direct fd access is not possible (for example, if the asset is
148 * compressed).
149 */
150int AAsset_openFileDescriptor(AAsset* asset, off_t* outStart, off_t* outLength);
151
152/**
153 * Open a new file descriptor that can be used to read the asset data.
154 *
155 * Uses a 64-bit number for the offset and length instead of 32-bit instead of
156 * as AAsset_openFileDescriptor does.
157 *
158 * Returns < 0 if direct fd access is not possible (for example, if the asset is
159 * compressed).
160 */
161int AAsset_openFileDescriptor64(AAsset* asset, off64_t* outStart, off64_t* outLength);
162
163/**
164 * Returns whether this asset's internal buffer is allocated in ordinary RAM (i.e. not
165 * mmapped).
166 */
167int AAsset_isAllocated(AAsset* asset);
168
169
170
171#ifdef __cplusplus
172};
173#endif
174
175#endif      // ANDROID_ASSET_MANAGER_H
176