third_party/brotli/dec/state.h

   1 /* Copyright 2015 Google Inc. All Rights Reserved.
   2
   3    Licensed under the Apache License, Version 2.0 (the "License");
   4    you may not use this file except in compliance with the License.
   5    You may obtain a copy of the License at
   6
   7    http://www.apache.org/licenses/LICENSE-2.0
   8
   9    Unless required by applicable law or agreed to in writing, software
  10    distributed under the License is distributed on an "AS IS" BASIS,
  11    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  12    See the License for the specific language governing permissions and
  13    limitations under the License.
  14 */
  15
  16 /* Brotli state for partial streaming decoding. */
  17
  18 #ifndef BROTLI_DEC_STATE_H_
  19 #define BROTLI_DEC_STATE_H_
  20
  21 #include <stdio.h>
  22 #include "./bit_reader.h"
  23 #include "./huffman.h"
  24 #include "./streams.h"
  25 #include "./types.h"
  26
  27 #if defined(__cplusplus) || defined(c_plusplus)
  28 extern "C" {
  29 #endif
  30
  31 typedef enum {
  32   BROTLI_STATE_UNINITED = 0,
  33   BROTLI_STATE_BITREADER_WARMUP = 1,
  34   BROTLI_STATE_METABLOCK_BEGIN = 10,
  35   BROTLI_STATE_METABLOCK_HEADER_1 = 11,
  36   BROTLI_STATE_METABLOCK_HEADER_2 = 12,
  37   BROTLI_STATE_BLOCK_BEGIN = 13,
  38   BROTLI_STATE_BLOCK_INNER = 14,
  39   BROTLI_STATE_BLOCK_DISTANCE = 15,
  40   BROTLI_STATE_BLOCK_POST = 16,
  41   BROTLI_STATE_UNCOMPRESSED = 17,
  42   BROTLI_STATE_METABLOCK_DONE = 20,
  43   BROTLI_STATE_HUFFMAN_CODE_0 = 30,
  44   BROTLI_STATE_HUFFMAN_CODE_1 = 31,
  45   BROTLI_STATE_HUFFMAN_CODE_2 = 32,
  46   BROTLI_STATE_CONTEXT_MAP_1 = 33,
  47   BROTLI_STATE_CONTEXT_MAP_2 = 34,
  48   BROTLI_STATE_TREE_GROUP = 35,
  49   BROTLI_STATE_SUB_NONE = 50,
  50   BROTLI_STATE_SUB_UNCOMPRESSED_SHORT = 51,
  51   BROTLI_STATE_SUB_UNCOMPRESSED_FILL = 52,
  52   BROTLI_STATE_SUB_UNCOMPRESSED_COPY = 53,
  53   BROTLI_STATE_SUB_UNCOMPRESSED_WARMUP = 54,
  54   BROTLI_STATE_SUB_HUFFMAN_LENGTH_BEGIN = 60,
  55   BROTLI_STATE_SUB_HUFFMAN_LENGTH_SYMBOLS = 61,
  56   BROTLI_STATE_SUB_HUFFMAN_DONE = 62,
  57   BROTLI_STATE_SUB_TREE_GROUP = 70,
  58   BROTLI_STATE_SUB_CONTEXT_MAP_HUFFMAN = 80,
  59   BROTLI_STATE_SUB_CONTEXT_MAPS = 81,
  60   BROTLI_STATE_DONE = 100
  61 } BrotliRunningState;
  62
  63 typedef struct {
  64   BrotliRunningState state;
  65   BrotliRunningState sub_state[2];  /* State inside function call */
  66
  67   int pos;
  68   int input_end;
  69   int window_bits;
  70   int max_backward_distance;
  71   int max_distance;
  72   int ringbuffer_size;
  73   int ringbuffer_mask;
  74   uint8_t* ringbuffer;
  75   uint8_t* ringbuffer_end;
  76   /* This ring buffer holds a few past copy distances that will be used by */
  77   /* some special distance codes. */
  78   int dist_rb[4];
  79   int dist_rb_idx;
  80   /* The previous 2 bytes used for context. */
  81   uint8_t prev_byte1;
  82   uint8_t prev_byte2;
  83   HuffmanTreeGroup hgroup[3];
  84   HuffmanCode* block_type_trees;
  85   HuffmanCode* block_len_trees;
  86   BrotliBitReader br;
  87   /* This counter is reused for several disjoint loops. */
  88   int loop_counter;
  89   /* This is true if the literal context map histogram type always matches the
  90   block type. It is then not needed to keep the context (faster decoding). */
  91   int trivial_literal_context;
  92
  93   int meta_block_remaining_len;
  94   int is_uncompressed;
  95   int block_length[3];
  96   int block_type[3];
  97   int num_block_types[3];
  98   int block_type_rb[6];
  99   int block_type_rb_index[3];
 100   int distance_postfix_bits;
 101   int num_direct_distance_codes;
 102   int distance_postfix_mask;
 103   int num_distance_codes;
 104   uint8_t* context_map;
 105   uint8_t* context_modes;
 106   int num_literal_htrees;
 107   uint8_t* dist_context_map;
 108   int num_dist_htrees;
 109   int context_offset;
 110   uint8_t* context_map_slice;
 111   uint8_t literal_htree_index;
 112   int dist_context_offset;
 113   uint8_t* dist_context_map_slice;
 114   uint8_t dist_htree_index;
 115   int context_lookup_offset1;
 116   int context_lookup_offset2;
 117   uint8_t context_mode;
 118   HuffmanCode* htree_command;
 119
 120   int cmd_code;
 121   int range_idx;
 122   int insert_code;
 123   int copy_code;
 124   int insert_length;
 125   int copy_length;
 126   int distance_code;
 127   int distance;
 128   const uint8_t* copy_src;
 129   uint8_t* copy_dst;
 130
 131   /* For CopyUncompressedBlockToOutput */
 132   int nbytes;
 133
 134   /* For HuffmanTreeGroupDecode */
 135   int htrees_decoded;
 136
 137   /* For ReadHuffmanCodeLengths */
 138   int symbol;
 139   uint8_t prev_code_len;
 140   int repeat;
 141   uint8_t repeat_code_len;
 142   int space;
 143   HuffmanCode table[32];
 144   uint8_t code_length_code_lengths[18];
 145
 146   /* For ReadHuffmanCode */
 147   int simple_code_or_skip;
 148   uint8_t* code_lengths;
 149
 150   /* For HuffmanTreeGroupDecode */
 151   int htree_index;
 152   HuffmanCode* next;
 153
 154   /* For DecodeContextMap */
 155   int context_index;
 156   int max_run_length_prefix;
 157   HuffmanCode* context_map_table;
 158 } BrotliState;
 159
 160 void BrotliStateInit(BrotliState* s);
 161 void BrotliStateCleanup(BrotliState* s);
 162
 163 #if defined(__cplusplus) || defined(c_plusplus)
 164 } /* extern "C" */
 165 #endif
 166
 167 #endif  /* BROTLI_DEC_STATE_H_ */