camera_metadata.h revision f5fb8a5516876c5a48cc44b4f1c99504e0b9f245
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_CORE_INCLUDE_ANDROID_CAMERA_METADATA_H 18#define SYSTEM_CORE_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 * Size in bytes of each entry type 97 */ 98ANDROID_API 99extern size_t camera_metadata_type_size[NUM_TYPES]; 100 101/** 102 * Main definitions for the metadata entry and array structures 103 * ============================================================================= 104 */ 105 106/** 107 * A packet of metadata. This is a list of metadata entries, each of which has 108 * an integer tag to identify its meaning, 'type' and 'count' field, and the 109 * data, which contains a 'count' number of entries of type 'type'. The packet 110 * has a fixed capacity for entries and for extra data. A new entry uses up one 111 * entry slot, and possibly some amount of data capacity; the function 112 * calculate_camera_metadata_entry_data_size() provides the amount of data 113 * capacity that would be used up by an entry. 114 * 115 * Entries are not sorted by default, and are not forced to be unique - multiple 116 * entries with the same tag are allowed. The packet will not dynamically resize 117 * when full. 118 * 119 * The packet is contiguous in memory, with size in bytes given by 120 * get_camera_metadata_size(). Therefore, it can be copied safely with memcpy() 121 * to a buffer of sufficient size. The copy_camera_metadata() function is 122 * intended for eliminating unused capacity in the destination packet. 123 */ 124struct camera_metadata; 125typedef struct camera_metadata camera_metadata_t; 126 127/** 128 * Functions for manipulating camera metadata 129 * ============================================================================= 130 */ 131 132/** 133 * Allocate a new camera_metadata structure, with some initial space for entries 134 * and extra data. The entry_capacity is measured in entry counts, and 135 * data_capacity in bytes. The resulting structure is all contiguous in memory, 136 * and can be freed with free_camera_metadata(). 137 */ 138ANDROID_API 139camera_metadata_t *allocate_camera_metadata(size_t entry_capacity, 140 size_t data_capacity); 141 142/** 143 * Place a camera metadata structure into an existing buffer. Returns NULL if 144 * the buffer is too small for the requested number of reserved entries and 145 * bytes of data. The entry_capacity is measured in entry counts, and 146 * data_capacity in bytes. If the buffer is larger than the required space, 147 * unused space will be left at the end. If successful, returns a pointer to the 148 * metadata header placed at the start of the buffer. It is the caller's 149 * responsibility to free the original buffer; do not call 150 * free_camera_metadata() with the returned pointer. 151 */ 152ANDROID_API 153camera_metadata_t *place_camera_metadata(void *dst, size_t dst_size, 154 size_t entry_capacity, 155 size_t data_capacity); 156 157/** 158 * Free a camera_metadata structure. Should only be used with structures 159 * allocated with allocate_camera_metadata(). 160 */ 161ANDROID_API 162void free_camera_metadata(camera_metadata_t *metadata); 163 164/** 165 * Calculate the buffer size needed for a metadata structure of entry_count 166 * metadata entries, needing a total of data_count bytes of extra data storage. 167 */ 168ANDROID_API 169size_t calculate_camera_metadata_size(size_t entry_count, 170 size_t data_count); 171 172/** 173 * Get current size of entire metadata structure in bytes, including reserved 174 * but unused space. 175 */ 176ANDROID_API 177size_t get_camera_metadata_size(const camera_metadata_t *metadata); 178 179/** 180 * Get size of entire metadata buffer in bytes, not including reserved but 181 * unused space. This is the amount of space needed by copy_camera_metadata for 182 * its dst buffer. 183 */ 184ANDROID_API 185size_t get_camera_metadata_compact_size(const camera_metadata_t *metadata); 186 187/** 188 * Get the current number of entries in the metadata packet. 189 */ 190ANDROID_API 191size_t get_camera_metadata_entry_count(const camera_metadata_t *metadata); 192 193/** 194 * Get the maximum number of entries that could fit in the metadata packet. 195 */ 196ANDROID_API 197size_t get_camera_metadata_entry_capacity(const camera_metadata_t *metadata); 198 199/** 200 * Get the current count of bytes used for value storage in the metadata packet. 201 */ 202ANDROID_API 203size_t get_camera_metadata_data_count(const camera_metadata_t *metadata); 204 205/** 206 * Get the maximum count of bytes that could be used for value storage in the 207 * metadata packet. 208 */ 209ANDROID_API 210size_t get_camera_metadata_data_capacity(const camera_metadata_t *metadata); 211 212/** 213 * Copy a metadata structure to a memory buffer, compacting it along the 214 * way. That is, in the copied structure, entry_count == entry_capacity, and 215 * data_count == data_capacity. 216 * 217 * If dst_size > get_camera_metadata_compact_size(), the unused bytes are at the 218 * end of the buffer. If dst_size < get_camera_metadata_compact_size(), returns 219 * NULL. Otherwise returns a pointer to the metadata structure header placed at 220 * the start of dst. 221 * 222 * Since the buffer was not allocated by allocate_camera_metadata, the caller is 223 * responsible for freeing the underlying buffer when needed; do not call 224 * free_camera_metadata. 225 */ 226ANDROID_API 227camera_metadata_t *copy_camera_metadata(void *dst, size_t dst_size, 228 const camera_metadata_t *src); 229 230/** 231 * Append camera metadata in src to an existing metadata structure in dst. This 232 * does not resize the destination structure, so if it is too small, a non-zero 233 * value is returned. On success, 0 is returned. Appending onto a sorted 234 * structure results in a non-sorted combined structure. 235 */ 236ANDROID_API 237int append_camera_metadata(camera_metadata_t *dst, const camera_metadata_t *src); 238 239/** 240 * Calculate the number of bytes of extra data a given metadata entry will take 241 * up. That is, if entry of 'type' with a payload of 'data_count' values is 242 * added, how much will the value returned by get_camera_metadata_data_count() 243 * be increased? This value may be zero, if no extra data storage is needed. 244 */ 245ANDROID_API 246size_t calculate_camera_metadata_entry_data_size(uint8_t type, 247 size_t data_count); 248 249/** 250 * Add a metadata entry to a metadata structure. Returns 0 if the addition 251 * succeeded. Returns a non-zero value if there is insufficient reserved space 252 * left to add the entry, or if the tag is unknown. data_count is the number of 253 * entries in the data array of the tag's type, not a count of 254 * bytes. Vendor-defined tags can not be added using this method, unless 255 * set_vendor_tag_query_ops() has been called first. Entries are always added to 256 * the end of the structure (highest index), so after addition, a 257 * previously-sorted array will be marked as unsorted. 258 */ 259ANDROID_API 260int add_camera_metadata_entry(camera_metadata_t *dst, 261 uint32_t tag, 262 const void *data, 263 size_t data_count); 264 265/** 266 * Sort the metadata buffer for fast searching. If already marked as sorted, 267 * does nothing. Adding or appending entries to the buffer will place the buffer 268 * back into an unsorted state. 269 */ 270ANDROID_API 271int sort_camera_metadata(camera_metadata_t *dst); 272 273/** 274 * Get metadata entry at position index in the metadata buffer. 275 * 276 * src and index are inputs; the passed-in entry is updated with the details of 277 * the entry. The data pointer points to the real data in the buffer, and can be 278 * updated as long as the data count does not change. 279 */ 280ANDROID_API 281int get_camera_metadata_entry(camera_metadata_t *src, 282 size_t index, 283 camera_metadata_entry_t *entry); 284 285/** 286 * Find an entry with given tag value. If not found, returns -ENOENT. Otherwise, 287 * returns entry contents like get_camera_metadata_entry. 288 * 289 * If multiple entries with the same tag exist, does not have any guarantees on 290 * which is returned. To speed up searching for tags, sort the metadata 291 * structure first by calling sort_camera_metadata(). 292 */ 293ANDROID_API 294int find_camera_metadata_entry(camera_metadata_t *src, 295 uint32_t tag, 296 camera_metadata_entry_t *entry); 297 298/** 299 * Delete an entry at given index. This is an expensive operation, since it 300 * requires repacking entries and possibly entry data. This also invalidates any 301 * existing camera_metadata_entry.data pointers to this buffer. Sorting is 302 * maintained. 303 */ 304ANDROID_API 305int delete_camera_metadata_entry(camera_metadata_t *dst, 306 size_t index); 307 308/** 309 * Updates a metadata entry with new data. If the data size is changing, may 310 * need to adjust the data array, making this an O(N) operation. If the data 311 * size is the same or still fits in the entry space, this is O(1). Maintains 312 * sorting, but invalidates camera_metadata_entry instances that point to the 313 * updated entry. If a non-NULL value is passed in to entry, the entry structure 314 * is updated to match the new buffer state. Returns a non-zero value if there 315 * is no room for the new data in the buffer. 316 */ 317ANDROID_API 318int update_camera_metadata_entry(camera_metadata_t *dst, 319 size_t index, 320 const void *data, 321 size_t data_count, 322 camera_metadata_entry_t *updated_entry); 323 324/** 325 * Retrieve human-readable name of section the tag is in. Returns NULL if 326 * no such tag is defined. Returns NULL for tags in the vendor section, unless 327 * set_vendor_tag_query_ops() has been used. 328 */ 329ANDROID_API 330const char *get_camera_metadata_section_name(uint32_t tag); 331 332/** 333 * Retrieve human-readable name of tag (not including section). Returns NULL if 334 * no such tag is defined. Returns NULL for tags in the vendor section, unless 335 * set_vendor_tag_query_ops() has been used. 336 */ 337ANDROID_API 338const char *get_camera_metadata_tag_name(uint32_t tag); 339 340/** 341 * Retrieve the type of a tag. Returns -1 if no such tag is defined. Returns -1 342 * for tags in the vendor section, unless set_vendor_tag_query_ops() has been 343 * used. 344 */ 345ANDROID_API 346int get_camera_metadata_tag_type(uint32_t tag); 347 348/** 349 * Set up vendor-specific tag query methods. These are needed to properly add 350 * entries with vendor-specified tags and to use the 351 * get_camera_metadata_section_name, _tag_name, and _tag_type methods with 352 * vendor tags. Returns 0 on success. 353 */ 354typedef struct vendor_tag_query_ops vendor_tag_query_ops_t; 355struct vendor_tag_query_ops { 356 /** 357 * Get vendor section name for a vendor-specified entry tag. Only called for 358 * tags >= 0x80000000. The section name must start with the name of the 359 * vendor in the Java package style. For example, CameraZoom inc must prefix 360 * their sections with "com.camerazoom." Must return NULL if the tag is 361 * outside the bounds of vendor-defined sections. 362 */ 363 const char *(*get_camera_vendor_section_name)( 364 const vendor_tag_query_ops_t *v, 365 uint32_t tag); 366 /** 367 * Get tag name for a vendor-specified entry tag. Only called for tags >= 368 * 0x80000000. Must return NULL if the tag is outside the bounds of 369 * vendor-defined sections. 370 */ 371 const char *(*get_camera_vendor_tag_name)( 372 const vendor_tag_query_ops_t *v, 373 uint32_t tag); 374 /** 375 * Get tag type for a vendor-specified entry tag. Only called for tags >= 376 * 0x80000000. Must return -1 if the tag is outside the bounds of 377 * vendor-defined sections. 378 */ 379 int (*get_camera_vendor_tag_type)( 380 const vendor_tag_query_ops_t *v, 381 uint32_t tag); 382}; 383 384ANDROID_API 385int set_camera_metadata_vendor_tag_ops(const vendor_tag_query_ops_t *query_ops); 386 387/** 388 * Print fields in the metadata to the log. 389 * verbosity = 0: Only tag entry information 390 * verbosity = 1: Tag entry information plus at most 16 data values 391 * verbosity = 2: All information 392 */ 393ANDROID_API 394void dump_camera_metadata(const camera_metadata_t *metadata, 395 int fd, 396 int verbosity); 397 398#ifdef __cplusplus 399} 400#endif 401 402#endif 403