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 * @addtogroup Asset
19 * @{
20 */
21
22/**
23 * @file asset_manager.h
24 */
25
26#ifndef ANDROID_ASSET_MANAGER_H
27#define ANDROID_ASSET_MANAGER_H
28
29#ifdef __cplusplus
30extern "C" {
31#endif
32
33struct AAssetManager;
34/**
35 * {@link AAssetManager} provides access to an application's raw assets by
36 * creating {@link AAsset} objects.
37 *
38 * AAssetManager is a wrapper to the low-level native implementation
39 * of the java {@link AAssetManager}, a pointer can be obtained using
40 * AAssetManager_fromJava().
41 *
42 * The asset hierarchy may be examined like a filesystem, using
43 * {@link AAssetDir} objects to peruse a single directory.
44 *
45 * A native {@link AAssetManager} pointer may be shared across multiple threads.
46 */
47typedef struct AAssetManager AAssetManager;
48
49struct AAssetDir;
50/**
51 * {@link AAssetDir} provides access to a chunk of the asset hierarchy as if
52 * it were a single directory. The contents are populated by the
53 * {@link AAssetManager}.
54 *
55 * The list of files will be sorted in ascending order by ASCII value.
56 */
57typedef struct AAssetDir AAssetDir;
58
59struct AAsset;
60/**
61 * {@link AAsset} provides access to a read-only asset.
62 *
63 * {@link AAsset} objects are NOT thread-safe, and should not be shared across
64 * threads.
65 */
66typedef struct AAsset AAsset;
67
68/** Available access modes for opening assets with {@link AAssetManager_open} */
69enum {
70    /** No specific information about how data will be accessed. **/
71    AASSET_MODE_UNKNOWN      = 0,
72    /** Read chunks, and seek forward and backward. */
73    AASSET_MODE_RANDOM       = 1,
74    /** Read sequentially, with an occasional forward seek. */
75    AASSET_MODE_STREAMING    = 2,
76    /** Caller plans to ask for a read-only buffer with all data. */
77    AASSET_MODE_BUFFER       = 3
78};
79
80
81/**
82 * Open the named directory within the asset hierarchy.  The directory can then
83 * be inspected with the AAssetDir functions.  To open the top-level directory,
84 * pass in "" as the dirName.
85 *
86 * The object returned here should be freed by calling AAssetDir_close().
87 */
88AAssetDir* AAssetManager_openDir(AAssetManager* mgr, const char* dirName);
89
90/**
91 * Open an asset.
92 *
93 * The object returned here should be freed by calling AAsset_close().
94 */
95AAsset* AAssetManager_open(AAssetManager* mgr, const char* filename, int mode);
96
97/**
98 * Iterate over the files in an asset directory.  A NULL string is returned
99 * when all the file names have been returned.
100 *
101 * The returned file name is suitable for passing to AAssetManager_open().
102 *
103 * The string returned here is owned by the AssetDir implementation and is not
104 * guaranteed to remain valid if any other calls are made on this AAssetDir
105 * instance.
106 */
107const char* AAssetDir_getNextFileName(AAssetDir* assetDir);
108
109/**
110 * Reset the iteration state of AAssetDir_getNextFileName() to the beginning.
111 */
112void AAssetDir_rewind(AAssetDir* assetDir);
113
114/**
115 * Close an opened AAssetDir, freeing any related resources.
116 */
117void AAssetDir_close(AAssetDir* assetDir);
118
119/**
120 * Attempt to read 'count' bytes of data from the current offset.
121 *
122 * Returns the number of bytes read, zero on EOF, or < 0 on error.
123 */
124int AAsset_read(AAsset* asset, void* buf, size_t count);
125
126/**
127 * Seek to the specified offset within the asset data.  'whence' uses the
128 * same constants as lseek()/fseek().
129 *
130 * Returns the new position on success, or (off_t) -1 on error.
131 */
132off_t AAsset_seek(AAsset* asset, off_t offset, int whence);
133
134/**
135 * Seek to the specified offset within the asset data.  'whence' uses the
136 * same constants as lseek()/fseek().
137 *
138 * Uses 64-bit data type for large files as opposed to the 32-bit type used
139 * by AAsset_seek.
140 *
141 * Returns the new position on success, or (off64_t) -1 on error.
142 */
143off64_t AAsset_seek64(AAsset* asset, off64_t offset, int whence);
144
145/**
146 * Close the asset, freeing all associated resources.
147 */
148void AAsset_close(AAsset* asset);
149
150/**
151 * Get a pointer to a buffer holding the entire contents of the assset.
152 *
153 * Returns NULL on failure.
154 */
155const void* AAsset_getBuffer(AAsset* asset);
156
157/**
158 * Report the total size of the asset data.
159 */
160off_t AAsset_getLength(AAsset* asset);
161
162/**
163 * Report the total size of the asset data. Reports the size using a 64-bit
164 * number insted of 32-bit as AAsset_getLength.
165 */
166off64_t AAsset_getLength64(AAsset* asset);
167
168/**
169 * Report the total amount of asset data that can be read from the current position.
170 */
171off_t AAsset_getRemainingLength(AAsset* asset);
172
173/**
174 * Report the total amount of asset data that can be read from the current position.
175 *
176 * Uses a 64-bit number instead of a 32-bit number as AAsset_getRemainingLength does.
177 */
178off64_t AAsset_getRemainingLength64(AAsset* asset);
179
180/**
181 * Open a new file descriptor that can be used to read the asset data. If the
182 * start or length cannot be represented by a 32-bit number, it will be
183 * truncated. If the file is large, use AAsset_openFileDescriptor64 instead.
184 *
185 * Returns < 0 if direct fd access is not possible (for example, if the asset is
186 * compressed).
187 */
188int AAsset_openFileDescriptor(AAsset* asset, off_t* outStart, off_t* outLength);
189
190/**
191 * Open a new file descriptor that can be used to read the asset data.
192 *
193 * Uses a 64-bit number for the offset and length instead of 32-bit instead of
194 * as AAsset_openFileDescriptor does.
195 *
196 * Returns < 0 if direct fd access is not possible (for example, if the asset is
197 * compressed).
198 */
199int AAsset_openFileDescriptor64(AAsset* asset, off64_t* outStart, off64_t* outLength);
200
201/**
202 * Returns whether this asset's internal buffer is allocated in ordinary RAM (i.e. not
203 * mmapped).
204 */
205int AAsset_isAllocated(AAsset* asset);
206
207
208
209#ifdef __cplusplus
210};
211#endif
212
213#endif      // ANDROID_ASSET_MANAGER_H
214
215/** @} */
216