1 /* 2 * Copyright (C) 2012 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 SYSTEM_MEDIA_INCLUDE_ANDROID_CAMERA_METADATA_H 18 #define SYSTEM_MEDIA_INCLUDE_ANDROID_CAMERA_METADATA_H 19 20 #include <string.h> 21 #include <stdint.h> 22 #include <cutils/compiler.h> 23 24 #ifdef __cplusplus 25 extern "C" { 26 #endif 27 28 /** 29 * Tag hierarchy and enum definitions for camera_metadata_entry 30 * ============================================================================= 31 */ 32 33 /** 34 * Main enum definitions are in a separate file to make it easy to 35 * maintain 36 */ 37 #include "camera_metadata_tags.h" 38 39 /** 40 * Enum range for each top-level category 41 */ 42 ANDROID_API 43 extern unsigned int camera_metadata_section_bounds[ANDROID_SECTION_COUNT][2]; 44 ANDROID_API 45 extern const char *camera_metadata_section_names[ANDROID_SECTION_COUNT]; 46 47 /** 48 * Type definitions for camera_metadata_entry 49 * ============================================================================= 50 */ 51 enum { 52 // Unsigned 8-bit integer (uint8_t) 53 TYPE_BYTE = 0, 54 // Signed 32-bit integer (int32_t) 55 TYPE_INT32 = 1, 56 // 32-bit float (float) 57 TYPE_FLOAT = 2, 58 // Signed 64-bit integer (int64_t) 59 TYPE_INT64 = 3, 60 // 64-bit float (double) 61 TYPE_DOUBLE = 4, 62 // A 64-bit fraction (camera_metadata_rational_t) 63 TYPE_RATIONAL = 5, 64 // Number of type fields 65 NUM_TYPES 66 }; 67 68 typedef struct camera_metadata_rational { 69 int32_t numerator; 70 int32_t denominator; 71 } camera_metadata_rational_t; 72 73 /** 74 * A reference to a metadata entry in a buffer. 75 * 76 * The data union pointers point to the real data in the buffer, and can be 77 * modified in-place if the count does not need to change. The count is the 78 * number of entries in data of the entry's type, not a count of bytes. 79 */ 80 typedef struct camera_metadata_entry { 81 size_t index; 82 uint32_t tag; 83 uint8_t type; 84 size_t count; 85 union { 86 uint8_t *u8; 87 int32_t *i32; 88 float *f; 89 int64_t *i64; 90 double *d; 91 camera_metadata_rational_t *r; 92 } data; 93 } camera_metadata_entry_t; 94 95 /** 96 * A read-only reference to a metadata entry in a buffer. Identical to 97 * camera_metadata_entry in layout 98 */ 99 typedef struct camera_metadata_ro_entry { 100 size_t index; 101 uint32_t tag; 102 uint8_t type; 103 size_t count; 104 union { 105 const uint8_t *u8; 106 const int32_t *i32; 107 const float *f; 108 const int64_t *i64; 109 const double *d; 110 const camera_metadata_rational_t *r; 111 } data; 112 } camera_metadata_ro_entry_t; 113 114 /** 115 * Size in bytes of each entry type 116 */ 117 ANDROID_API 118 extern const size_t camera_metadata_type_size[NUM_TYPES]; 119 120 /** 121 * Human-readable name of each entry type 122 */ 123 ANDROID_API 124 extern const char* camera_metadata_type_names[NUM_TYPES]; 125 126 /** 127 * Main definitions for the metadata entry and array structures 128 * ============================================================================= 129 */ 130 131 /** 132 * A packet of metadata. This is a list of metadata entries, each of which has 133 * an integer tag to identify its meaning, 'type' and 'count' field, and the 134 * data, which contains a 'count' number of entries of type 'type'. The packet 135 * has a fixed capacity for entries and for extra data. A new entry uses up one 136 * entry slot, and possibly some amount of data capacity; the function 137 * calculate_camera_metadata_entry_data_size() provides the amount of data 138 * capacity that would be used up by an entry. 139 * 140 * Entries are not sorted by default, and are not forced to be unique - multiple 141 * entries with the same tag are allowed. The packet will not dynamically resize 142 * when full. 143 * 144 * The packet is contiguous in memory, with size in bytes given by 145 * get_camera_metadata_size(). Therefore, it can be copied safely with memcpy() 146 * to a buffer of sufficient size. The copy_camera_metadata() function is 147 * intended for eliminating unused capacity in the destination packet. 148 */ 149 struct camera_metadata; 150 typedef struct camera_metadata camera_metadata_t; 151 152 /** 153 * Functions for manipulating camera metadata 154 * ============================================================================= 155 */ 156 157 /** 158 * Allocate a new camera_metadata structure, with some initial space for entries 159 * and extra data. The entry_capacity is measured in entry counts, and 160 * data_capacity in bytes. The resulting structure is all contiguous in memory, 161 * and can be freed with free_camera_metadata(). 162 */ 163 ANDROID_API 164 camera_metadata_t *allocate_camera_metadata(size_t entry_capacity, 165 size_t data_capacity); 166 167 /** 168 * Place a camera metadata structure into an existing buffer. Returns NULL if 169 * the buffer is too small for the requested number of reserved entries and 170 * bytes of data. The entry_capacity is measured in entry counts, and 171 * data_capacity in bytes. If the buffer is larger than the required space, 172 * unused space will be left at the end. If successful, returns a pointer to the 173 * metadata header placed at the start of the buffer. It is the caller's 174 * responsibility to free the original buffer; do not call 175 * free_camera_metadata() with the returned pointer. 176 */ 177 ANDROID_API 178 camera_metadata_t *place_camera_metadata(void *dst, size_t dst_size, 179 size_t entry_capacity, 180 size_t data_capacity); 181 182 /** 183 * Free a camera_metadata structure. Should only be used with structures 184 * allocated with allocate_camera_metadata(). 185 */ 186 ANDROID_API 187 void free_camera_metadata(camera_metadata_t *metadata); 188 189 /** 190 * Calculate the buffer size needed for a metadata structure of entry_count 191 * metadata entries, needing a total of data_count bytes of extra data storage. 192 */ 193 ANDROID_API 194 size_t calculate_camera_metadata_size(size_t entry_count, 195 size_t data_count); 196 197 /** 198 * Get current size of entire metadata structure in bytes, including reserved 199 * but unused space. 200 */ 201 ANDROID_API 202 size_t get_camera_metadata_size(const camera_metadata_t *metadata); 203 204 /** 205 * Get size of entire metadata buffer in bytes, not including reserved but 206 * unused space. This is the amount of space needed by copy_camera_metadata for 207 * its dst buffer. 208 */ 209 ANDROID_API 210 size_t get_camera_metadata_compact_size(const camera_metadata_t *metadata); 211 212 /** 213 * Get the current number of entries in the metadata packet. 214 */ 215 ANDROID_API 216 size_t get_camera_metadata_entry_count(const camera_metadata_t *metadata); 217 218 /** 219 * Get the maximum number of entries that could fit in the metadata packet. 220 */ 221 ANDROID_API 222 size_t get_camera_metadata_entry_capacity(const camera_metadata_t *metadata); 223 224 /** 225 * Get the current count of bytes used for value storage in the metadata packet. 226 */ 227 ANDROID_API 228 size_t get_camera_metadata_data_count(const camera_metadata_t *metadata); 229 230 /** 231 * Get the maximum count of bytes that could be used for value storage in the 232 * metadata packet. 233 */ 234 ANDROID_API 235 size_t get_camera_metadata_data_capacity(const camera_metadata_t *metadata); 236 237 /** 238 * Copy a metadata structure to a memory buffer, compacting it along the 239 * way. That is, in the copied structure, entry_count == entry_capacity, and 240 * data_count == data_capacity. 241 * 242 * If dst_size > get_camera_metadata_compact_size(), the unused bytes are at the 243 * end of the buffer. If dst_size < get_camera_metadata_compact_size(), returns 244 * NULL. Otherwise returns a pointer to the metadata structure header placed at 245 * the start of dst. 246 * 247 * Since the buffer was not allocated by allocate_camera_metadata, the caller is 248 * responsible for freeing the underlying buffer when needed; do not call 249 * free_camera_metadata. 250 */ 251 ANDROID_API 252 camera_metadata_t *copy_camera_metadata(void *dst, size_t dst_size, 253 const camera_metadata_t *src); 254 255 /** 256 * Append camera metadata in src to an existing metadata structure in dst. This 257 * does not resize the destination structure, so if it is too small, a non-zero 258 * value is returned. On success, 0 is returned. Appending onto a sorted 259 * structure results in a non-sorted combined structure. 260 */ 261 ANDROID_API 262 int append_camera_metadata(camera_metadata_t *dst, const camera_metadata_t *src); 263 264 /** 265 * Clone an existing metadata buffer, compacting along the way. This is 266 * equivalent to allocating a new buffer of the minimum needed size, then 267 * appending the buffer to be cloned into the new buffer. The resulting buffer 268 * can be freed with free_camera_metadata(). Returns NULL if cloning failed. 269 */ 270 ANDROID_API 271 camera_metadata_t *clone_camera_metadata(const camera_metadata_t *src); 272 273 /** 274 * Calculate the number of bytes of extra data a given metadata entry will take 275 * up. That is, if entry of 'type' with a payload of 'data_count' values is 276 * added, how much will the value returned by get_camera_metadata_data_count() 277 * be increased? This value may be zero, if no extra data storage is needed. 278 */ 279 ANDROID_API 280 size_t calculate_camera_metadata_entry_data_size(uint8_t type, 281 size_t data_count); 282 283 /** 284 * Add a metadata entry to a metadata structure. Returns 0 if the addition 285 * succeeded. Returns a non-zero value if there is insufficient reserved space 286 * left to add the entry, or if the tag is unknown. data_count is the number of 287 * entries in the data array of the tag's type, not a count of 288 * bytes. Vendor-defined tags can not be added using this method, unless 289 * set_vendor_tag_query_ops() has been called first. Entries are always added to 290 * the end of the structure (highest index), so after addition, a 291 * previously-sorted array will be marked as unsorted. 292 */ 293 ANDROID_API 294 int add_camera_metadata_entry(camera_metadata_t *dst, 295 uint32_t tag, 296 const void *data, 297 size_t data_count); 298 299 /** 300 * Sort the metadata buffer for fast searching. If already marked as sorted, 301 * does nothing. Adding or appending entries to the buffer will place the buffer 302 * back into an unsorted state. 303 */ 304 ANDROID_API 305 int sort_camera_metadata(camera_metadata_t *dst); 306 307 /** 308 * Get metadata entry at position index in the metadata buffer. 309 * 310 * src and index are inputs; the passed-in entry is updated with the details of 311 * the entry. The data pointer points to the real data in the buffer, and can be 312 * updated as long as the data count does not change. 313 */ 314 ANDROID_API 315 int get_camera_metadata_entry(camera_metadata_t *src, 316 size_t index, 317 camera_metadata_entry_t *entry); 318 319 /** 320 * Find an entry with given tag value. If not found, returns -ENOENT. Otherwise, 321 * returns entry contents like get_camera_metadata_entry. 322 * 323 * If multiple entries with the same tag exist, does not have any guarantees on 324 * which is returned. To speed up searching for tags, sort the metadata 325 * structure first by calling sort_camera_metadata(). 326 */ 327 ANDROID_API 328 int find_camera_metadata_entry(camera_metadata_t *src, 329 uint32_t tag, 330 camera_metadata_entry_t *entry); 331 332 /** 333 * Find an entry with given tag value, but disallow editing the data 334 */ 335 ANDROID_API 336 int find_camera_metadata_ro_entry(const camera_metadata_t *src, 337 uint32_t tag, 338 camera_metadata_ro_entry_t *entry); 339 340 /** 341 * Delete an entry at given index. This is an expensive operation, since it 342 * requires repacking entries and possibly entry data. This also invalidates any 343 * existing camera_metadata_entry.data pointers to this buffer. Sorting is 344 * maintained. 345 */ 346 ANDROID_API 347 int delete_camera_metadata_entry(camera_metadata_t *dst, 348 size_t index); 349 350 /** 351 * Updates a metadata entry with new data. If the data size is changing, may 352 * need to adjust the data array, making this an O(N) operation. If the data 353 * size is the same or still fits in the entry space, this is O(1). Maintains 354 * sorting, but invalidates camera_metadata_entry instances that point to the 355 * updated entry. If a non-NULL value is passed in to entry, the entry structure 356 * is updated to match the new buffer state. Returns a non-zero value if there 357 * is no room for the new data in the buffer. 358 */ 359 ANDROID_API 360 int update_camera_metadata_entry(camera_metadata_t *dst, 361 size_t index, 362 const void *data, 363 size_t data_count, 364 camera_metadata_entry_t *updated_entry); 365 366 /** 367 * Set user pointer in buffer. This can be used for linking the metadata buffer 368 * with other associated data. This user pointer is not copied with 369 * copy_camera_metadata, and is unaffected by append or any other methods. 370 */ 371 ANDROID_API 372 int set_camera_metadata_user_pointer(camera_metadata_t *dst, void* user); 373 374 /** 375 * Retrieve user pointer in buffer. Returns NULL in user if 376 * set_camera_metadata_user_pointer has not been called with this buffer. 377 */ 378 ANDROID_API 379 int get_camera_metadata_user_pointer(camera_metadata_t *dst, void** user); 380 381 /** 382 * Retrieve human-readable name of section the tag is in. Returns NULL if 383 * no such tag is defined. Returns NULL for tags in the vendor section, unless 384 * set_vendor_tag_query_ops() has been used. 385 */ 386 ANDROID_API 387 const char *get_camera_metadata_section_name(uint32_t tag); 388 389 /** 390 * Retrieve human-readable name of tag (not including section). Returns NULL if 391 * no such tag is defined. Returns NULL for tags in the vendor section, unless 392 * set_vendor_tag_query_ops() has been used. 393 */ 394 ANDROID_API 395 const char *get_camera_metadata_tag_name(uint32_t tag); 396 397 /** 398 * Retrieve the type of a tag. Returns -1 if no such tag is defined. Returns -1 399 * for tags in the vendor section, unless set_vendor_tag_query_ops() has been 400 * used. 401 */ 402 ANDROID_API 403 int get_camera_metadata_tag_type(uint32_t tag); 404 405 /** 406 * Set up vendor-specific tag query methods. These are needed to properly add 407 * entries with vendor-specified tags and to use the 408 * get_camera_metadata_section_name, _tag_name, and _tag_type methods with 409 * vendor tags. Returns 0 on success. 410 */ 411 typedef struct vendor_tag_query_ops vendor_tag_query_ops_t; 412 struct vendor_tag_query_ops { 413 /** 414 * Get vendor section name for a vendor-specified entry tag. Only called for 415 * tags >= 0x80000000. The section name must start with the name of the 416 * vendor in the Java package style. For example, CameraZoom inc must prefix 417 * their sections with "com.camerazoom." Must return NULL if the tag is 418 * outside the bounds of vendor-defined sections. 419 */ 420 const char *(*get_camera_vendor_section_name)( 421 const vendor_tag_query_ops_t *v, 422 uint32_t tag); 423 /** 424 * Get tag name for a vendor-specified entry tag. Only called for tags >= 425 * 0x80000000. Must return NULL if the tag is outside the bounds of 426 * vendor-defined sections. 427 */ 428 const char *(*get_camera_vendor_tag_name)( 429 const vendor_tag_query_ops_t *v, 430 uint32_t tag); 431 /** 432 * Get tag type for a vendor-specified entry tag. Only called for tags >= 433 * 0x80000000. Must return -1 if the tag is outside the bounds of 434 * vendor-defined sections. 435 */ 436 int (*get_camera_vendor_tag_type)( 437 const vendor_tag_query_ops_t *v, 438 uint32_t tag); 439 }; 440 441 ANDROID_API 442 int set_camera_metadata_vendor_tag_ops(const vendor_tag_query_ops_t *query_ops); 443 444 /** 445 * Print fields in the metadata to the log. 446 * verbosity = 0: Only tag entry information 447 * verbosity = 1: Tag entry information plus at most 16 data values 448 * verbosity = 2: All information 449 */ 450 ANDROID_API 451 void dump_camera_metadata(const camera_metadata_t *metadata, 452 int fd, 453 int verbosity); 454 455 /** 456 * Print fields in the metadata to the log; adds indentation parameter, which 457 * specifies the number of spaces to insert before each line of the dump 458 */ 459 ANDROID_API 460 void dump_indented_camera_metadata(const camera_metadata_t *metadata, 461 int fd, 462 int verbosity, 463 int indentation); 464 465 #ifdef __cplusplus 466 } 467 #endif 468 469 #endif 470
