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      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 #include "./state.h"
      8 
      9 #include <stdlib.h>  /* free, malloc */
     10 
     11 #include <brotli/types.h>
     12 #include "./huffman.h"
     13 
     14 #if defined(__cplusplus) || defined(c_plusplus)
     15 extern "C" {
     16 #endif
     17 
     18 BROTLI_BOOL BrotliDecoderStateInit(BrotliDecoderState* s,
     19     brotli_alloc_func alloc_func, brotli_free_func free_func, void* opaque) {
     20   if (!alloc_func) {
     21     s->alloc_func = BrotliDefaultAllocFunc;
     22     s->free_func = BrotliDefaultFreeFunc;
     23     s->memory_manager_opaque = 0;
     24   } else {
     25     s->alloc_func = alloc_func;
     26     s->free_func = free_func;
     27     s->memory_manager_opaque = opaque;
     28   }
     29 
     30   s->error_code = 0; /* BROTLI_DECODER_NO_ERROR */
     31 
     32   BrotliInitBitReader(&s->br);
     33   s->state = BROTLI_STATE_UNINITED;
     34   s->large_window = 0;
     35   s->substate_metablock_header = BROTLI_STATE_METABLOCK_HEADER_NONE;
     36   s->substate_uncompressed = BROTLI_STATE_UNCOMPRESSED_NONE;
     37   s->substate_decode_uint8 = BROTLI_STATE_DECODE_UINT8_NONE;
     38   s->substate_read_block_length = BROTLI_STATE_READ_BLOCK_LENGTH_NONE;
     39 
     40   s->buffer_length = 0;
     41   s->loop_counter = 0;
     42   s->pos = 0;
     43   s->rb_roundtrips = 0;
     44   s->partial_pos_out = 0;
     45 
     46   s->block_type_trees = NULL;
     47   s->block_len_trees = NULL;
     48   s->ringbuffer = NULL;
     49   s->ringbuffer_size = 0;
     50   s->new_ringbuffer_size = 0;
     51   s->ringbuffer_mask = 0;
     52 
     53   s->context_map = NULL;
     54   s->context_modes = NULL;
     55   s->dist_context_map = NULL;
     56   s->context_map_slice = NULL;
     57   s->dist_context_map_slice = NULL;
     58 
     59   s->literal_hgroup.codes = NULL;
     60   s->literal_hgroup.htrees = NULL;
     61   s->insert_copy_hgroup.codes = NULL;
     62   s->insert_copy_hgroup.htrees = NULL;
     63   s->distance_hgroup.codes = NULL;
     64   s->distance_hgroup.htrees = NULL;
     65 
     66   s->is_last_metablock = 0;
     67   s->is_uncompressed = 0;
     68   s->is_metadata = 0;
     69   s->should_wrap_ringbuffer = 0;
     70   s->canny_ringbuffer_allocation = 1;
     71 
     72   s->window_bits = 0;
     73   s->max_distance = 0;
     74   s->dist_rb[0] = 16;
     75   s->dist_rb[1] = 15;
     76   s->dist_rb[2] = 11;
     77   s->dist_rb[3] = 4;
     78   s->dist_rb_idx = 0;
     79   s->block_type_trees = NULL;
     80   s->block_len_trees = NULL;
     81 
     82   s->mtf_upper_bound = 63;
     83 
     84   s->dictionary = BrotliGetDictionary();
     85   s->transforms = BrotliGetTransforms();
     86 
     87   return BROTLI_TRUE;
     88 }
     89 
     90 void BrotliDecoderStateMetablockBegin(BrotliDecoderState* s) {
     91   s->meta_block_remaining_len = 0;
     92   s->block_length[0] = 1U << 24;
     93   s->block_length[1] = 1U << 24;
     94   s->block_length[2] = 1U << 24;
     95   s->num_block_types[0] = 1;
     96   s->num_block_types[1] = 1;
     97   s->num_block_types[2] = 1;
     98   s->block_type_rb[0] = 1;
     99   s->block_type_rb[1] = 0;
    100   s->block_type_rb[2] = 1;
    101   s->block_type_rb[3] = 0;
    102   s->block_type_rb[4] = 1;
    103   s->block_type_rb[5] = 0;
    104   s->context_map = NULL;
    105   s->context_modes = NULL;
    106   s->dist_context_map = NULL;
    107   s->context_map_slice = NULL;
    108   s->literal_htree = NULL;
    109   s->dist_context_map_slice = NULL;
    110   s->dist_htree_index = 0;
    111   s->context_lookup = NULL;
    112   s->literal_hgroup.codes = NULL;
    113   s->literal_hgroup.htrees = NULL;
    114   s->insert_copy_hgroup.codes = NULL;
    115   s->insert_copy_hgroup.htrees = NULL;
    116   s->distance_hgroup.codes = NULL;
    117   s->distance_hgroup.htrees = NULL;
    118 }
    119 
    120 void BrotliDecoderStateCleanupAfterMetablock(BrotliDecoderState* s) {
    121   BROTLI_DECODER_FREE(s, s->context_modes);
    122   BROTLI_DECODER_FREE(s, s->context_map);
    123   BROTLI_DECODER_FREE(s, s->dist_context_map);
    124   BROTLI_DECODER_FREE(s, s->literal_hgroup.htrees);
    125   BROTLI_DECODER_FREE(s, s->insert_copy_hgroup.htrees);
    126   BROTLI_DECODER_FREE(s, s->distance_hgroup.htrees);
    127 }
    128 
    129 void BrotliDecoderStateCleanup(BrotliDecoderState* s) {
    130   BrotliDecoderStateCleanupAfterMetablock(s);
    131 
    132   BROTLI_DECODER_FREE(s, s->ringbuffer);
    133   BROTLI_DECODER_FREE(s, s->block_type_trees);
    134 }
    135 
    136 BROTLI_BOOL BrotliDecoderHuffmanTreeGroupInit(BrotliDecoderState* s,
    137     HuffmanTreeGroup* group, uint32_t alphabet_size_max,
    138     uint32_t alphabet_size_limit, uint32_t ntrees) {
    139   /* 376 = 256 (1-st level table) + 4 + 7 + 15 + 31 + 63 (2-nd level mix-tables)
    140      This number is discovered "unlimited" "enough" calculator; it is actually
    141      a wee bigger than required in several cases (especially for alphabets with
    142      less than 16 symbols). */
    143   const size_t max_table_size = alphabet_size_limit + 376;
    144   const size_t code_size = sizeof(HuffmanCode) * ntrees * max_table_size;
    145   const size_t htree_size = sizeof(HuffmanCode*) * ntrees;
    146   /* Pointer alignment is, hopefully, wider than sizeof(HuffmanCode). */
    147   HuffmanCode** p = (HuffmanCode**)BROTLI_DECODER_ALLOC(s,
    148       code_size + htree_size);
    149   group->alphabet_size_max = (uint16_t)alphabet_size_max;
    150   group->alphabet_size_limit = (uint16_t)alphabet_size_limit;
    151   group->num_htrees = (uint16_t)ntrees;
    152   group->htrees = p;
    153   group->codes = (HuffmanCode*)(&p[ntrees]);
    154   return !!p;
    155 }
    156 
    157 #if defined(__cplusplus) || defined(c_plusplus)
    158 }  /* extern "C" */
    159 #endif
    160