camera_metadata.h revision 5a2255d05c8fd480e1de8dd3384897799b26ecd9
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 25extern "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 */ 42ANDROID_API 43extern unsigned int camera_metadata_section_bounds[ANDROID_SECTION_COUNT][2]; 44ANDROID_API 45extern const char *camera_metadata_section_names[ANDROID_SECTION_COUNT]; 46 47/** 48 * Type definitions for camera_metadata_entry 49 * ============================================================================= 50 */ 51enum { 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 68typedef 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 */ 80typedef 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 */ 99typedef 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 */ 117ANDROID_API 118extern const size_t camera_metadata_type_size[NUM_TYPES]; 119 120/** 121 * Human-readable name of each entry type 122 */ 123ANDROID_API 124extern 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 */ 149struct camera_metadata; 150typedef 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 */ 163ANDROID_API 164camera_metadata_t *allocate_camera_metadata(size_t entry_capacity, 165 size_t data_capacity); 166 167/** 168 * Allocate a new camera_metadata structure of size src_size. Copy the data, 169 * ignoring alignment, and then attempt validation. If validation 170 * fails, free the memory and return NULL. Otherwise return the pointer. 171 * 172 * The resulting pointer can be freed with free_camera_metadata(). 173 */ 174ANDROID_API 175camera_metadata_t *allocate_copy_camera_metadata_checked( 176 const camera_metadata_t *src, 177 size_t src_size); 178 179/** 180 * Place a camera metadata structure into an existing buffer. Returns NULL if 181 * the buffer is too small for the requested number of reserved entries and 182 * bytes of data. The entry_capacity is measured in entry counts, and 183 * data_capacity in bytes. If the buffer is larger than the required space, 184 * unused space will be left at the end. If successful, returns a pointer to the 185 * metadata header placed at the start of the buffer. It is the caller's 186 * responsibility to free the original buffer; do not call 187 * free_camera_metadata() with the returned pointer. 188 */ 189ANDROID_API 190camera_metadata_t *place_camera_metadata(void *dst, size_t dst_size, 191 size_t entry_capacity, 192 size_t data_capacity); 193 194/** 195 * Free a camera_metadata structure. Should only be used with structures 196 * allocated with allocate_camera_metadata(). 197 */ 198ANDROID_API 199void free_camera_metadata(camera_metadata_t *metadata); 200 201/** 202 * Calculate the buffer size needed for a metadata structure of entry_count 203 * metadata entries, needing a total of data_count bytes of extra data storage. 204 */ 205ANDROID_API 206size_t calculate_camera_metadata_size(size_t entry_count, 207 size_t data_count); 208 209/** 210 * Get current size of entire metadata structure in bytes, including reserved 211 * but unused space. 212 */ 213ANDROID_API 214size_t get_camera_metadata_size(const camera_metadata_t *metadata); 215 216/** 217 * Get size of entire metadata buffer in bytes, not including reserved but 218 * unused space. This is the amount of space needed by copy_camera_metadata for 219 * its dst buffer. 220 */ 221ANDROID_API 222size_t get_camera_metadata_compact_size(const camera_metadata_t *metadata); 223 224/** 225 * Get the current number of entries in the metadata packet. 226 */ 227ANDROID_API 228size_t get_camera_metadata_entry_count(const camera_metadata_t *metadata); 229 230/** 231 * Get the maximum number of entries that could fit in the metadata packet. 232 */ 233ANDROID_API 234size_t get_camera_metadata_entry_capacity(const camera_metadata_t *metadata); 235 236/** 237 * Get the current count of bytes used for value storage in the metadata packet. 238 */ 239ANDROID_API 240size_t get_camera_metadata_data_count(const camera_metadata_t *metadata); 241 242/** 243 * Get the maximum count of bytes that could be used for value storage in the 244 * metadata packet. 245 */ 246ANDROID_API 247size_t get_camera_metadata_data_capacity(const camera_metadata_t *metadata); 248 249/** 250 * Copy a metadata structure to a memory buffer, compacting it along the 251 * way. That is, in the copied structure, entry_count == entry_capacity, and 252 * data_count == data_capacity. 253 * 254 * If dst_size > get_camera_metadata_compact_size(), the unused bytes are at the 255 * end of the buffer. If dst_size < get_camera_metadata_compact_size(), returns 256 * NULL. Otherwise returns a pointer to the metadata structure header placed at 257 * the start of dst. 258 * 259 * Since the buffer was not allocated by allocate_camera_metadata, the caller is 260 * responsible for freeing the underlying buffer when needed; do not call 261 * free_camera_metadata. 262 */ 263ANDROID_API 264camera_metadata_t *copy_camera_metadata(void *dst, size_t dst_size, 265 const camera_metadata_t *src); 266 267/** 268 * Validate that a metadata is structurally sane. That is, its internal 269 * state is such that we won't get buffer overflows or run into other 270 * 'impossible' issues when calling the other API functions. 271 * 272 * This is useful in particular after copying the binary metadata blob 273 * from an untrusted source, since passing this check means the data is at least 274 * consistent. 275 * 276 * The expected_size argument is optional. 277 * 278 * Returns 0 on success. A non-0 value is returned on error. 279 */ 280ANDROID_API 281int validate_camera_metadata_structure(const camera_metadata_t *metadata, 282 const size_t *expected_size); 283 284/** 285 * Append camera metadata in src to an existing metadata structure in dst. This 286 * does not resize the destination structure, so if it is too small, a non-zero 287 * value is returned. On success, 0 is returned. Appending onto a sorted 288 * structure results in a non-sorted combined structure. 289 */ 290ANDROID_API 291int append_camera_metadata(camera_metadata_t *dst, const camera_metadata_t *src); 292 293/** 294 * Clone an existing metadata buffer, compacting along the way. This is 295 * equivalent to allocating a new buffer of the minimum needed size, then 296 * appending the buffer to be cloned into the new buffer. The resulting buffer 297 * can be freed with free_camera_metadata(). Returns NULL if cloning failed. 298 */ 299ANDROID_API 300camera_metadata_t *clone_camera_metadata(const camera_metadata_t *src); 301 302/** 303 * Calculate the number of bytes of extra data a given metadata entry will take 304 * up. That is, if entry of 'type' with a payload of 'data_count' values is 305 * added, how much will the value returned by get_camera_metadata_data_count() 306 * be increased? This value may be zero, if no extra data storage is needed. 307 */ 308ANDROID_API 309size_t calculate_camera_metadata_entry_data_size(uint8_t type, 310 size_t data_count); 311 312/** 313 * Add a metadata entry to a metadata structure. Returns 0 if the addition 314 * succeeded. Returns a non-zero value if there is insufficient reserved space 315 * left to add the entry, or if the tag is unknown. data_count is the number of 316 * entries in the data array of the tag's type, not a count of 317 * bytes. Vendor-defined tags can not be added using this method, unless 318 * set_vendor_tag_query_ops() has been called first. Entries are always added to 319 * the end of the structure (highest index), so after addition, a 320 * previously-sorted array will be marked as unsorted. 321 */ 322ANDROID_API 323int add_camera_metadata_entry(camera_metadata_t *dst, 324 uint32_t tag, 325 const void *data, 326 size_t data_count); 327 328/** 329 * Sort the metadata buffer for fast searching. If already marked as sorted, 330 * does nothing. Adding or appending entries to the buffer will place the buffer 331 * back into an unsorted state. 332 */ 333ANDROID_API 334int sort_camera_metadata(camera_metadata_t *dst); 335 336/** 337 * Get metadata entry at position index in the metadata buffer. 338 * 339 * src and index are inputs; the passed-in entry is updated with the details of 340 * the entry. The data pointer points to the real data in the buffer, and can be 341 * updated as long as the data count does not change. 342 */ 343ANDROID_API 344int get_camera_metadata_entry(camera_metadata_t *src, 345 size_t index, 346 camera_metadata_entry_t *entry); 347 348/** 349 * Find an entry with given tag value. If not found, returns -ENOENT. Otherwise, 350 * returns entry contents like get_camera_metadata_entry. 351 * 352 * If multiple entries with the same tag exist, does not have any guarantees on 353 * which is returned. To speed up searching for tags, sort the metadata 354 * structure first by calling sort_camera_metadata(). 355 */ 356ANDROID_API 357int find_camera_metadata_entry(camera_metadata_t *src, 358 uint32_t tag, 359 camera_metadata_entry_t *entry); 360 361/** 362 * Find an entry with given tag value, but disallow editing the data 363 */ 364ANDROID_API 365int find_camera_metadata_ro_entry(const camera_metadata_t *src, 366 uint32_t tag, 367 camera_metadata_ro_entry_t *entry); 368 369/** 370 * Delete an entry at given index. This is an expensive operation, since it 371 * requires repacking entries and possibly entry data. This also invalidates any 372 * existing camera_metadata_entry.data pointers to this buffer. Sorting is 373 * maintained. 374 */ 375ANDROID_API 376int delete_camera_metadata_entry(camera_metadata_t *dst, 377 size_t index); 378 379/** 380 * Updates a metadata entry with new data. If the data size is changing, may 381 * need to adjust the data array, making this an O(N) operation. If the data 382 * size is the same or still fits in the entry space, this is O(1). Maintains 383 * sorting, but invalidates camera_metadata_entry instances that point to the 384 * updated entry. If a non-NULL value is passed in to entry, the entry structure 385 * is updated to match the new buffer state. Returns a non-zero value if there 386 * is no room for the new data in the buffer. 387 */ 388ANDROID_API 389int update_camera_metadata_entry(camera_metadata_t *dst, 390 size_t index, 391 const void *data, 392 size_t data_count, 393 camera_metadata_entry_t *updated_entry); 394 395/** 396 * Retrieve human-readable name of section the tag is in. Returns NULL if 397 * no such tag is defined. Returns NULL for tags in the vendor section, unless 398 * set_vendor_tag_query_ops() has been used. 399 */ 400ANDROID_API 401const char *get_camera_metadata_section_name(uint32_t tag); 402 403/** 404 * Retrieve human-readable name of tag (not including section). Returns NULL if 405 * no such tag is defined. Returns NULL for tags in the vendor section, unless 406 * set_vendor_tag_query_ops() has been used. 407 */ 408ANDROID_API 409const char *get_camera_metadata_tag_name(uint32_t tag); 410 411/** 412 * Retrieve the type of a tag. Returns -1 if no such tag is defined. Returns -1 413 * for tags in the vendor section, unless set_vendor_tag_query_ops() has been 414 * used. 415 */ 416ANDROID_API 417int get_camera_metadata_tag_type(uint32_t tag); 418 419/** 420 * Set up vendor-specific tag query methods. These are needed to properly add 421 * entries with vendor-specified tags and to use the 422 * get_camera_metadata_section_name, _tag_name, and _tag_type methods with 423 * vendor tags. Returns 0 on success. 424 */ 425typedef struct vendor_tag_query_ops vendor_tag_query_ops_t; 426struct vendor_tag_query_ops { 427 /** 428 * Get vendor section name for a vendor-specified entry tag. Only called for 429 * tags >= 0x80000000. The section name must start with the name of the 430 * vendor in the Java package style. For example, CameraZoom inc must prefix 431 * their sections with "com.camerazoom." Must return NULL if the tag is 432 * outside the bounds of vendor-defined sections. 433 */ 434 const char *(*get_camera_vendor_section_name)( 435 const vendor_tag_query_ops_t *v, 436 uint32_t tag); 437 /** 438 * Get tag name for a vendor-specified entry tag. Only called for tags >= 439 * 0x80000000. Must return NULL if the tag is outside the bounds of 440 * vendor-defined sections. 441 */ 442 const char *(*get_camera_vendor_tag_name)( 443 const vendor_tag_query_ops_t *v, 444 uint32_t tag); 445 /** 446 * Get tag type for a vendor-specified entry tag. Only called for tags >= 447 * 0x80000000. Must return -1 if the tag is outside the bounds of 448 * vendor-defined sections. 449 */ 450 int (*get_camera_vendor_tag_type)( 451 const vendor_tag_query_ops_t *v, 452 uint32_t tag); 453 /** 454 * Get the number of vendor tags supported on this platform. Used to 455 * calculate the size of buffer needed for holding the array of all tags 456 * returned by get_camera_vendor_tags(). 457 */ 458 int (*get_camera_vendor_tag_count)( 459 const vendor_tag_query_ops_t *v); 460 /** 461 * Fill an array with all the supported vendor tags on this platform. 462 * get_camera_vendor_tag_count() returns the number of tags supported, and 463 * tag_array should be allocated with enough space to hold all of the tags. 464 */ 465 void (*get_camera_vendor_tags)( 466 const vendor_tag_query_ops_t *v, 467 uint32_t *tag_array); 468}; 469 470ANDROID_API 471int set_camera_metadata_vendor_tag_ops(const vendor_tag_query_ops_t *query_ops); 472 473/** 474 * Print fields in the metadata to the log. 475 * verbosity = 0: Only tag entry information 476 * verbosity = 1: Tag entry information plus at most 16 data values 477 * verbosity = 2: All information 478 */ 479ANDROID_API 480void dump_camera_metadata(const camera_metadata_t *metadata, 481 int fd, 482 int verbosity); 483 484/** 485 * Print fields in the metadata to the log; adds indentation parameter, which 486 * specifies the number of spaces to insert before each line of the dump 487 */ 488ANDROID_API 489void dump_indented_camera_metadata(const camera_metadata_t *metadata, 490 int fd, 491 int verbosity, 492 int indentation); 493 494/** 495 * Prints the specified tag value as a string. Only works for enum tags. 496 * Returns 0 on success, -1 on failure. 497 */ 498ANDROID_API 499int camera_metadata_enum_snprint(uint32_t tag, 500 uint32_t value, 501 char *dst, 502 size_t size); 503 504#ifdef __cplusplus 505} 506#endif 507 508#endif 509