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 #include <sys/cdefs.h> 30 #include <sys/types.h> 31 32 #ifdef __cplusplus 33 extern "C" { 34 #endif 35 36 #if !defined(__ANDROID__) && !defined(__RENAME_IF_FILE_OFFSET64) 37 #define __RENAME_IF_FILE_OFFSET64(x) 38 #endif 39 40 struct AAssetManager; 41 /** 42 * {@link AAssetManager} provides access to an application's raw assets by 43 * creating {@link AAsset} objects. 44 * 45 * AAssetManager is a wrapper to the low-level native implementation 46 * of the java {@link AAssetManager}, a pointer can be obtained using 47 * AAssetManager_fromJava(). 48 * 49 * The asset hierarchy may be examined like a filesystem, using 50 * {@link AAssetDir} objects to peruse a single directory. 51 * 52 * A native {@link AAssetManager} pointer may be shared across multiple threads. 53 */ 54 typedef struct AAssetManager AAssetManager; 55 56 struct AAssetDir; 57 /** 58 * {@link AAssetDir} provides access to a chunk of the asset hierarchy as if 59 * it were a single directory. The contents are populated by the 60 * {@link AAssetManager}. 61 * 62 * The list of files will be sorted in ascending order by ASCII value. 63 */ 64 typedef struct AAssetDir AAssetDir; 65 66 struct AAsset; 67 /** 68 * {@link AAsset} provides access to a read-only asset. 69 * 70 * {@link AAsset} objects are NOT thread-safe, and should not be shared across 71 * threads. 72 */ 73 typedef struct AAsset AAsset; 74 75 /** Available access modes for opening assets with {@link AAssetManager_open} */ 76 enum { 77 /** No specific information about how data will be accessed. **/ 78 AASSET_MODE_UNKNOWN = 0, 79 /** Read chunks, and seek forward and backward. */ 80 AASSET_MODE_RANDOM = 1, 81 /** Read sequentially, with an occasional forward seek. */ 82 AASSET_MODE_STREAMING = 2, 83 /** Caller plans to ask for a read-only buffer with all data. */ 84 AASSET_MODE_BUFFER = 3 85 }; 86 87 88 /** 89 * Open the named directory within the asset hierarchy. The directory can then 90 * be inspected with the AAssetDir functions. To open the top-level directory, 91 * pass in "" as the dirName. 92 * 93 * The object returned here should be freed by calling AAssetDir_close(). 94 */ 95 AAssetDir* AAssetManager_openDir(AAssetManager* mgr, const char* dirName); 96 97 /** 98 * Open an asset. 99 * 100 * The object returned here should be freed by calling AAsset_close(). 101 */ 102 AAsset* AAssetManager_open(AAssetManager* mgr, const char* filename, int mode); 103 104 /** 105 * Iterate over the files in an asset directory. A NULL string is returned 106 * when all the file names have been returned. 107 * 108 * The returned file name is suitable for passing to AAssetManager_open(). 109 * 110 * The string returned here is owned by the AssetDir implementation and is not 111 * guaranteed to remain valid if any other calls are made on this AAssetDir 112 * instance. 113 */ 114 const char* AAssetDir_getNextFileName(AAssetDir* assetDir); 115 116 /** 117 * Reset the iteration state of AAssetDir_getNextFileName() to the beginning. 118 */ 119 void AAssetDir_rewind(AAssetDir* assetDir); 120 121 /** 122 * Close an opened AAssetDir, freeing any related resources. 123 */ 124 void AAssetDir_close(AAssetDir* assetDir); 125 126 /** 127 * Attempt to read 'count' bytes of data from the current offset. 128 * 129 * Returns the number of bytes read, zero on EOF, or < 0 on error. 130 */ 131 int AAsset_read(AAsset* asset, void* buf, size_t count); 132 133 /** 134 * Seek to the specified offset within the asset data. 'whence' uses the 135 * same constants as lseek()/fseek(). 136 * 137 * Returns the new position on success, or (off_t) -1 on error. 138 */ 139 off_t AAsset_seek(AAsset* asset, off_t offset, int whence) 140 __RENAME_IF_FILE_OFFSET64(AAsset_seek64); 141 142 /** 143 * Seek to the specified offset within the asset data. 'whence' uses the 144 * same constants as lseek()/fseek(). 145 * 146 * Uses 64-bit data type for large files as opposed to the 32-bit type used 147 * by AAsset_seek. 148 * 149 * Returns the new position on success, or (off64_t) -1 on error. 150 */ 151 off64_t AAsset_seek64(AAsset* asset, off64_t offset, int whence); 152 153 /** 154 * Close the asset, freeing all associated resources. 155 */ 156 void AAsset_close(AAsset* asset); 157 158 /** 159 * Get a pointer to a buffer holding the entire contents of the assset. 160 * 161 * Returns NULL on failure. 162 */ 163 const void* AAsset_getBuffer(AAsset* asset); 164 165 /** 166 * Report the total size of the asset data. 167 */ 168 off_t AAsset_getLength(AAsset* asset) 169 __RENAME_IF_FILE_OFFSET64(AAsset_getLength64); 170 171 /** 172 * Report the total size of the asset data. Reports the size using a 64-bit 173 * number insted of 32-bit as AAsset_getLength. 174 */ 175 off64_t AAsset_getLength64(AAsset* asset); 176 177 /** 178 * Report the total amount of asset data that can be read from the current position. 179 */ 180 off_t AAsset_getRemainingLength(AAsset* asset) 181 __RENAME_IF_FILE_OFFSET64(AAsset_getRemainingLength64); 182 183 /** 184 * Report the total amount of asset data that can be read from the current position. 185 * 186 * Uses a 64-bit number instead of a 32-bit number as AAsset_getRemainingLength does. 187 */ 188 off64_t AAsset_getRemainingLength64(AAsset* asset); 189 190 /** 191 * Open a new file descriptor that can be used to read the asset data. If the 192 * start or length cannot be represented by a 32-bit number, it will be 193 * truncated. If the file is large, use AAsset_openFileDescriptor64 instead. 194 * 195 * Returns < 0 if direct fd access is not possible (for example, if the asset is 196 * compressed). 197 */ 198 int AAsset_openFileDescriptor(AAsset* asset, off_t* outStart, off_t* outLength) 199 __RENAME_IF_FILE_OFFSET64(AAsset_openFileDescriptor64); 200 201 /** 202 * Open a new file descriptor that can be used to read the asset data. 203 * 204 * Uses a 64-bit number for the offset and length instead of 32-bit instead of 205 * as AAsset_openFileDescriptor does. 206 * 207 * Returns < 0 if direct fd access is not possible (for example, if the asset is 208 * compressed). 209 */ 210 int AAsset_openFileDescriptor64(AAsset* asset, off64_t* outStart, off64_t* outLength); 211 212 /** 213 * Returns whether this asset's internal buffer is allocated in ordinary RAM (i.e. not 214 * mmapped). 215 */ 216 int AAsset_isAllocated(AAsset* asset); 217 218 219 220 #ifdef __cplusplus 221 }; 222 #endif 223 224 #endif // ANDROID_ASSET_MANAGER_H 225 226 /** @} */ 227