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_METADATA = 18,
  43   BROTLI_STATE_BLOCK_INNER_WRITE = 19,
  44   BROTLI_STATE_METABLOCK_DONE = 20,
  45   BROTLI_STATE_BLOCK_POST_WRITE_1 = 21,
  46   BROTLI_STATE_BLOCK_POST_WRITE_2 = 22,
  47   BROTLI_STATE_BLOCK_POST_CONTINUE = 23,
  48   BROTLI_STATE_HUFFMAN_CODE_0 = 30,
  49   BROTLI_STATE_HUFFMAN_CODE_1 = 31,
  50   BROTLI_STATE_HUFFMAN_CODE_2 = 32,
  51   BROTLI_STATE_CONTEXT_MAP_1 = 33,
  52   BROTLI_STATE_CONTEXT_MAP_2 = 34,
  53   BROTLI_STATE_TREE_GROUP = 35,
  54   BROTLI_STATE_SUB_NONE = 50,
  55   BROTLI_STATE_SUB_UNCOMPRESSED_SHORT = 51,
  56   BROTLI_STATE_SUB_UNCOMPRESSED_FILL = 52,
  57   BROTLI_STATE_SUB_UNCOMPRESSED_COPY = 53,
  58   BROTLI_STATE_SUB_UNCOMPRESSED_WARMUP = 54,
  59   BROTLI_STATE_SUB_UNCOMPRESSED_WRITE_1 = 55,
  60   BROTLI_STATE_SUB_UNCOMPRESSED_WRITE_2 = 56,
  61   BROTLI_STATE_SUB_UNCOMPRESSED_WRITE_3 = 57,
  62   BROTLI_STATE_SUB_HUFFMAN_LENGTH_BEGIN = 60,
  63   BROTLI_STATE_SUB_HUFFMAN_LENGTH_SYMBOLS = 61,
  64   BROTLI_STATE_SUB_HUFFMAN_DONE = 62,
  65   BROTLI_STATE_SUB_TREE_GROUP = 70,
  66   BROTLI_STATE_SUB_CONTEXT_MAP_HUFFMAN = 80,
  67   BROTLI_STATE_SUB_CONTEXT_MAPS = 81,
  68   BROTLI_STATE_DONE = 100
  69 } BrotliRunningState;
  70
  71 typedef struct {
  72   BrotliRunningState state;
  73   BrotliRunningState sub_state[2];  /* State inside function call */
  74
  75   int pos;
  76   int input_end;
  77   int window_bits;
  78   int max_backward_distance;
  79   int max_distance;
  80   int ringbuffer_size;
  81   int ringbuffer_mask;
  82   uint8_t* ringbuffer;
  83   uint8_t* ringbuffer_end;
  84   /* This ring buffer holds a few past copy distances that will be used by */
  85   /* some special distance codes. */
  86   int dist_rb[4];
  87   int dist_rb_idx;
  88   /* The previous 2 bytes used for context. */
  89   uint8_t prev_byte1;
  90   uint8_t prev_byte2;
  91   HuffmanTreeGroup hgroup[3];
  92   HuffmanCode* block_type_trees;
  93   HuffmanCode* block_len_trees;
  94   BrotliBitReader br;
  95   /* This counter is reused for several disjoint loops. */
  96   int loop_counter;
  97   /* This is true if the literal context map histogram type always matches the
  98   block type. It is then not needed to keep the context (faster decoding). */
  99   int trivial_literal_context;
 100
 101   int meta_block_remaining_len;
 102   int is_metadata;
 103   int is_uncompressed;
 104   int block_length[3];
 105   int block_type[3];
 106   int num_block_types[3];
 107   int block_type_rb[6];
 108   int block_type_rb_index[3];
 109   int distance_postfix_bits;
 110   int num_direct_distance_codes;
 111   int distance_postfix_mask;
 112   int num_distance_codes;
 113   uint8_t* context_map;
 114   uint8_t* context_modes;
 115   int num_literal_htrees;
 116   uint8_t* dist_context_map;
 117   int num_dist_htrees;
 118   int context_offset;
 119   uint8_t* context_map_slice;
 120   uint8_t literal_htree_index;
 121   int dist_context_offset;
 122   uint8_t* dist_context_map_slice;
 123   uint8_t dist_htree_index;
 124   int context_lookup_offset1;
 125   int context_lookup_offset2;
 126   uint8_t context_mode;
 127   HuffmanCode* htree_command;
 128
 129   int cmd_code;
 130   int range_idx;
 131   int insert_code;
 132   int copy_code;
 133   int insert_length;
 134   int copy_length;
 135   int distance_code;
 136   int distance;
 137   const uint8_t* copy_src;
 138   uint8_t* copy_dst;
 139
 140   /* For CopyUncompressedBlockToOutput */
 141   int nbytes;
 142
 143   /* For partial write operations */
 144   int partially_written;
 145
 146   /* For HuffmanTreeGroupDecode */
 147   int htrees_decoded;
 148
 149   /* For ReadHuffmanCodeLengths */
 150   int symbol;
 151   uint8_t prev_code_len;
 152   int repeat;
 153   uint8_t repeat_code_len;
 154   int space;
 155   HuffmanCode table[32];
 156   uint8_t code_length_code_lengths[18];
 157
 158   /* For ReadHuffmanCode */
 159   int simple_code_or_skip;
 160   uint8_t* code_lengths;
 161
 162   /* For HuffmanTreeGroupDecode */
 163   int htree_index;
 164   HuffmanCode* next;
 165
 166   /* For DecodeContextMap */
 167   int context_index;
 168   int max_run_length_prefix;
 169   HuffmanCode* context_map_table;
 170 } BrotliState;
 171
 172 void BrotliStateInit(BrotliState* s);
 173 void BrotliStateCleanup(BrotliState* s);
 174
 175 #if defined(__cplusplus) || defined(c_plusplus)
 176 } /* extern "C" */
 177 #endif
 178
 179 #endif  /* BROTLI_DEC_STATE_H_ */