1 /* Copyright 2015 Google Inc. All Rights Reserved. 2 3 Distributed under MIT license. 4 See file LICENSE for detail or copy at https://opensource.org/licenses/MIT 5 */ 6 7 /* Brotli state for partial streaming decoding. */ 8 9 #ifndef BROTLI_DEC_STATE_H_ 10 #define BROTLI_DEC_STATE_H_ 11 12 #include "../common/constants.h" 13 #include "../common/dictionary.h" 14 #include "../common/platform.h" 15 #include "../common/transform.h" 16 #include <brotli/types.h> 17 #include "./bit_reader.h" 18 #include "./huffman.h" 19 20 #if defined(__cplusplus) || defined(c_plusplus) 21 extern "C" { 22 #endif 23 24 /* Graphviz diagram that describes state transitions: 25 26 digraph States { 27 graph [compound=true] 28 concentrate=true 29 node [shape="box"] 30 31 UNINITED -> {LARGE_WINDOW_BITS -> INITIALIZE} 32 subgraph cluster_metablock_workflow { 33 style="rounded" 34 label=< <B>METABLOCK CYCLE</B> > 35 METABLOCK_BEGIN -> METABLOCK_HEADER 36 METABLOCK_HEADER:sw -> METADATA 37 METABLOCK_HEADER:s -> UNCOMPRESSED 38 METABLOCK_HEADER:se -> METABLOCK_DONE:ne 39 METADATA:s -> METABLOCK_DONE:w 40 UNCOMPRESSED:s -> METABLOCK_DONE:n 41 METABLOCK_DONE:e -> METABLOCK_BEGIN:e [constraint="false"] 42 } 43 INITIALIZE -> METABLOCK_BEGIN 44 METABLOCK_DONE -> DONE 45 46 subgraph cluster_compressed_metablock { 47 style="rounded" 48 label=< <B>COMPRESSED METABLOCK</B> > 49 50 subgraph cluster_command { 51 style="rounded" 52 label=< <B>HOT LOOP</B> > 53 54 _METABLOCK_DONE_PORT_ [shape=point style=invis] 55 56 { 57 // Set different shape for nodes returning from "compressed metablock". 58 node [shape=invhouse]; CMD_INNER CMD_POST_DECODE_LITERALS; 59 CMD_POST_WRAP_COPY; CMD_INNER_WRITE; CMD_POST_WRITE_1; 60 } 61 62 CMD_BEGIN -> CMD_INNER -> CMD_POST_DECODE_LITERALS -> CMD_POST_WRAP_COPY 63 64 // IO ("write") nodes are not in the hot loop! 65 CMD_INNER_WRITE [style=dashed] 66 CMD_INNER -> CMD_INNER_WRITE 67 CMD_POST_WRITE_1 [style=dashed] 68 CMD_POST_DECODE_LITERALS -> CMD_POST_WRITE_1 69 CMD_POST_WRITE_2 [style=dashed] 70 CMD_POST_WRAP_COPY -> CMD_POST_WRITE_2 71 72 CMD_POST_WRITE_1 -> CMD_BEGIN:s [constraint="false"] 73 CMD_INNER_WRITE -> {CMD_INNER CMD_POST_DECODE_LITERALS} 74 [constraint="false"] 75 CMD_BEGIN:ne -> CMD_POST_DECODE_LITERALS [constraint="false"] 76 CMD_POST_WRAP_COPY -> CMD_BEGIN [constraint="false"] 77 CMD_POST_DECODE_LITERALS -> CMD_BEGIN:ne [constraint="false"] 78 CMD_POST_WRITE_2 -> CMD_POST_WRAP_COPY [constraint="false"] 79 {rank=same; CMD_BEGIN; CMD_INNER; CMD_POST_DECODE_LITERALS; 80 CMD_POST_WRAP_COPY} 81 {rank=same; CMD_INNER_WRITE; CMD_POST_WRITE_1; CMD_POST_WRITE_2} 82 83 {CMD_INNER CMD_POST_DECODE_LITERALS CMD_POST_WRAP_COPY} -> 84 _METABLOCK_DONE_PORT_ [style=invis] 85 {CMD_INNER_WRITE CMD_POST_WRITE_1} -> _METABLOCK_DONE_PORT_ 86 [constraint="false" style=invis] 87 } 88 89 BEFORE_COMPRESSED_METABLOCK_HEADER:s -> HUFFMAN_CODE_0:n 90 HUFFMAN_CODE_0 -> HUFFMAN_CODE_1 -> HUFFMAN_CODE_2 -> HUFFMAN_CODE_3 91 HUFFMAN_CODE_0 -> METABLOCK_HEADER_2 -> CONTEXT_MODES -> CONTEXT_MAP_1 92 CONTEXT_MAP_1 -> CONTEXT_MAP_2 -> TREE_GROUP 93 TREE_GROUP -> BEFORE_COMPRESSED_METABLOCK_BODY:e 94 BEFORE_COMPRESSED_METABLOCK_BODY:s -> CMD_BEGIN:n 95 96 HUFFMAN_CODE_3:e -> HUFFMAN_CODE_0:ne [constraint="false"] 97 {rank=same; HUFFMAN_CODE_0; HUFFMAN_CODE_1; HUFFMAN_CODE_2; HUFFMAN_CODE_3} 98 {rank=same; METABLOCK_HEADER_2; CONTEXT_MODES; CONTEXT_MAP_1; CONTEXT_MAP_2; 99 TREE_GROUP} 100 } 101 METABLOCK_HEADER:e -> BEFORE_COMPRESSED_METABLOCK_HEADER:n 102 103 _METABLOCK_DONE_PORT_ -> METABLOCK_DONE:se 104 [constraint="false" ltail=cluster_command] 105 106 UNINITED [shape=Mdiamond]; 107 DONE [shape=Msquare]; 108 } 109 110 111 */ 112 113 typedef enum { 114 BROTLI_STATE_UNINITED, 115 BROTLI_STATE_LARGE_WINDOW_BITS, 116 BROTLI_STATE_INITIALIZE, 117 BROTLI_STATE_METABLOCK_BEGIN, 118 BROTLI_STATE_METABLOCK_HEADER, 119 BROTLI_STATE_METABLOCK_HEADER_2, 120 BROTLI_STATE_CONTEXT_MODES, 121 BROTLI_STATE_COMMAND_BEGIN, 122 BROTLI_STATE_COMMAND_INNER, 123 BROTLI_STATE_COMMAND_POST_DECODE_LITERALS, 124 BROTLI_STATE_COMMAND_POST_WRAP_COPY, 125 BROTLI_STATE_UNCOMPRESSED, 126 BROTLI_STATE_METADATA, 127 BROTLI_STATE_COMMAND_INNER_WRITE, 128 BROTLI_STATE_METABLOCK_DONE, 129 BROTLI_STATE_COMMAND_POST_WRITE_1, 130 BROTLI_STATE_COMMAND_POST_WRITE_2, 131 BROTLI_STATE_BEFORE_COMPRESSED_METABLOCK_HEADER, 132 BROTLI_STATE_HUFFMAN_CODE_0, 133 BROTLI_STATE_HUFFMAN_CODE_1, 134 BROTLI_STATE_HUFFMAN_CODE_2, 135 BROTLI_STATE_HUFFMAN_CODE_3, 136 BROTLI_STATE_CONTEXT_MAP_1, 137 BROTLI_STATE_CONTEXT_MAP_2, 138 BROTLI_STATE_TREE_GROUP, 139 BROTLI_STATE_BEFORE_COMPRESSED_METABLOCK_BODY, 140 BROTLI_STATE_DONE 141 } BrotliRunningState; 142 143 typedef enum { 144 BROTLI_STATE_METABLOCK_HEADER_NONE, 145 BROTLI_STATE_METABLOCK_HEADER_EMPTY, 146 BROTLI_STATE_METABLOCK_HEADER_NIBBLES, 147 BROTLI_STATE_METABLOCK_HEADER_SIZE, 148 BROTLI_STATE_METABLOCK_HEADER_UNCOMPRESSED, 149 BROTLI_STATE_METABLOCK_HEADER_RESERVED, 150 BROTLI_STATE_METABLOCK_HEADER_BYTES, 151 BROTLI_STATE_METABLOCK_HEADER_METADATA 152 } BrotliRunningMetablockHeaderState; 153 154 typedef enum { 155 BROTLI_STATE_UNCOMPRESSED_NONE, 156 BROTLI_STATE_UNCOMPRESSED_WRITE 157 } BrotliRunningUncompressedState; 158 159 typedef enum { 160 BROTLI_STATE_TREE_GROUP_NONE, 161 BROTLI_STATE_TREE_GROUP_LOOP 162 } BrotliRunningTreeGroupState; 163 164 typedef enum { 165 BROTLI_STATE_CONTEXT_MAP_NONE, 166 BROTLI_STATE_CONTEXT_MAP_READ_PREFIX, 167 BROTLI_STATE_CONTEXT_MAP_HUFFMAN, 168 BROTLI_STATE_CONTEXT_MAP_DECODE, 169 BROTLI_STATE_CONTEXT_MAP_TRANSFORM 170 } BrotliRunningContextMapState; 171 172 typedef enum { 173 BROTLI_STATE_HUFFMAN_NONE, 174 BROTLI_STATE_HUFFMAN_SIMPLE_SIZE, 175 BROTLI_STATE_HUFFMAN_SIMPLE_READ, 176 BROTLI_STATE_HUFFMAN_SIMPLE_BUILD, 177 BROTLI_STATE_HUFFMAN_COMPLEX, 178 BROTLI_STATE_HUFFMAN_LENGTH_SYMBOLS 179 } BrotliRunningHuffmanState; 180 181 typedef enum { 182 BROTLI_STATE_DECODE_UINT8_NONE, 183 BROTLI_STATE_DECODE_UINT8_SHORT, 184 BROTLI_STATE_DECODE_UINT8_LONG 185 } BrotliRunningDecodeUint8State; 186 187 typedef enum { 188 BROTLI_STATE_READ_BLOCK_LENGTH_NONE, 189 BROTLI_STATE_READ_BLOCK_LENGTH_SUFFIX 190 } BrotliRunningReadBlockLengthState; 191 192 typedef struct BrotliMetablockHeaderArena { 193 BrotliRunningTreeGroupState substate_tree_group; 194 BrotliRunningContextMapState substate_context_map; 195 BrotliRunningHuffmanState substate_huffman; 196 197 uint32_t sub_loop_counter; 198 199 uint32_t repeat_code_len; 200 uint32_t prev_code_len; 201 202 /* For ReadHuffmanCode. */ 203 uint32_t symbol; 204 uint32_t repeat; 205 uint32_t space; 206 207 /* Huffman table for "histograms". */ 208 HuffmanCode table[32]; 209 /* List of heads of symbol chains. */ 210 uint16_t* symbol_lists; 211 /* Storage from symbol_lists. */ 212 uint16_t symbols_lists_array[BROTLI_HUFFMAN_MAX_CODE_LENGTH + 1 + 213 BROTLI_NUM_COMMAND_SYMBOLS]; 214 /* Tails of symbol chains. */ 215 int next_symbol[32]; 216 uint8_t code_length_code_lengths[BROTLI_CODE_LENGTH_CODES]; 217 /* Population counts for the code lengths. */ 218 uint16_t code_length_histo[16]; 219 220 /* For HuffmanTreeGroupDecode. */ 221 int htree_index; 222 HuffmanCode* next; 223 224 /* For DecodeContextMap. */ 225 uint32_t context_index; 226 uint32_t max_run_length_prefix; 227 uint32_t code; 228 HuffmanCode context_map_table[BROTLI_HUFFMAN_MAX_SIZE_272]; 229 } BrotliMetablockHeaderArena; 230 231 typedef struct BrotliMetablockBodyArena { 232 uint8_t dist_extra_bits[544]; 233 uint32_t dist_offset[544]; 234 } BrotliMetablockBodyArena; 235 236 struct BrotliDecoderStateStruct { 237 BrotliRunningState state; 238 239 /* This counter is reused for several disjoint loops. */ 240 int loop_counter; 241 242 BrotliBitReader br; 243 244 brotli_alloc_func alloc_func; 245 brotli_free_func free_func; 246 void* memory_manager_opaque; 247 248 /* Temporary storage for remaining input. Brotli stream format is designed in 249 a way, that 64 bits are enough to make progress in decoding. */ 250 union { 251 uint64_t u64; 252 uint8_t u8[8]; 253 } buffer; 254 uint32_t buffer_length; 255 256 int pos; 257 int max_backward_distance; 258 int max_distance; 259 int ringbuffer_size; 260 int ringbuffer_mask; 261 int dist_rb_idx; 262 int dist_rb[4]; 263 int error_code; 264 uint8_t* ringbuffer; 265 uint8_t* ringbuffer_end; 266 HuffmanCode* htree_command; 267 const uint8_t* context_lookup; 268 uint8_t* context_map_slice; 269 uint8_t* dist_context_map_slice; 270 271 /* This ring buffer holds a few past copy distances that will be used by 272 some special distance codes. */ 273 HuffmanTreeGroup literal_hgroup; 274 HuffmanTreeGroup insert_copy_hgroup; 275 HuffmanTreeGroup distance_hgroup; 276 HuffmanCode* block_type_trees; 277 HuffmanCode* block_len_trees; 278 /* This is true if the literal context map histogram type always matches the 279 block type. It is then not needed to keep the context (faster decoding). */ 280 int trivial_literal_context; 281 /* Distance context is actual after command is decoded and before distance is 282 computed. After distance computation it is used as a temporary variable. */ 283 int distance_context; 284 int meta_block_remaining_len; 285 uint32_t block_length_index; 286 uint32_t block_length[3]; 287 uint32_t num_block_types[3]; 288 uint32_t block_type_rb[6]; 289 uint32_t distance_postfix_bits; 290 uint32_t num_direct_distance_codes; 291 uint32_t num_dist_htrees; 292 uint8_t* dist_context_map; 293 HuffmanCode* literal_htree; 294 uint8_t dist_htree_index; 295 296 int copy_length; 297 int distance_code; 298 299 /* For partial write operations. */ 300 size_t rb_roundtrips; /* how many times we went around the ring-buffer */ 301 size_t partial_pos_out; /* how much output to the user in total */ 302 303 /* For InverseMoveToFrontTransform. */ 304 uint32_t mtf_upper_bound; 305 uint32_t mtf[64 + 1]; 306 307 /* Less used attributes are at the end of this struct. */ 308 309 /* States inside function calls. */ 310 BrotliRunningMetablockHeaderState substate_metablock_header; 311 BrotliRunningUncompressedState substate_uncompressed; 312 BrotliRunningDecodeUint8State substate_decode_uint8; 313 BrotliRunningReadBlockLengthState substate_read_block_length; 314 315 unsigned int is_last_metablock : 1; 316 unsigned int is_uncompressed : 1; 317 unsigned int is_metadata : 1; 318 unsigned int should_wrap_ringbuffer : 1; 319 unsigned int canny_ringbuffer_allocation : 1; 320 unsigned int large_window : 1; 321 unsigned int size_nibbles : 8; 322 uint32_t window_bits; 323 324 int new_ringbuffer_size; 325 326 uint32_t num_literal_htrees; 327 uint8_t* context_map; 328 uint8_t* context_modes; 329 330 const BrotliDictionary* dictionary; 331 const BrotliTransforms* transforms; 332 333 uint32_t trivial_literal_contexts[8]; /* 256 bits */ 334 335 union { 336 BrotliMetablockHeaderArena header; 337 BrotliMetablockBodyArena body; 338 } arena; 339 }; 340 341 typedef struct BrotliDecoderStateStruct BrotliDecoderStateInternal; 342 #define BrotliDecoderState BrotliDecoderStateInternal 343 344 BROTLI_INTERNAL BROTLI_BOOL BrotliDecoderStateInit(BrotliDecoderState* s, 345 brotli_alloc_func alloc_func, brotli_free_func free_func, void* opaque); 346 BROTLI_INTERNAL void BrotliDecoderStateCleanup(BrotliDecoderState* s); 347 BROTLI_INTERNAL void BrotliDecoderStateMetablockBegin(BrotliDecoderState* s); 348 BROTLI_INTERNAL void BrotliDecoderStateCleanupAfterMetablock( 349 BrotliDecoderState* s); 350 BROTLI_INTERNAL BROTLI_BOOL BrotliDecoderHuffmanTreeGroupInit( 351 BrotliDecoderState* s, HuffmanTreeGroup* group, uint32_t alphabet_size_max, 352 uint32_t alphabet_size_limit, uint32_t ntrees); 353 354 #define BROTLI_DECODER_ALLOC(S, L) S->alloc_func(S->memory_manager_opaque, L) 355 356 #define BROTLI_DECODER_FREE(S, X) { \ 357 S->free_func(S->memory_manager_opaque, X); \ 358 X = NULL; \ 359 } 360 361 #if defined(__cplusplus) || defined(c_plusplus) 362 } /* extern "C" */ 363 #endif 364 365 #endif /* BROTLI_DEC_STATE_H_ */ 366
Indexes created Sat Jul 04 00:25:45 UTC 2026