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 | /* Algorithms for distributing the literals and commands of a metablock between |
8 | block types and contexts. */ |
9 | |
10 | #ifndef BROTLI_ENC_METABLOCK_H_ |
11 | #define BROTLI_ENC_METABLOCK_H_ |
12 | |
13 | #include "../common/context.h" |
14 | #include "../common/platform.h" |
15 | #include <brotli/types.h> |
16 | #include "./block_splitter.h" |
17 | #include "./command.h" |
18 | #include "./histogram.h" |
19 | #include "./memory.h" |
20 | #include "./quality.h" |
21 | |
22 | #if defined(__cplusplus) || defined(c_plusplus) |
23 | extern "C" { |
24 | #endif |
25 | |
26 | typedef struct MetaBlockSplit { |
27 | BlockSplit literal_split; |
28 | BlockSplit command_split; |
29 | BlockSplit distance_split; |
30 | uint32_t* literal_context_map; |
31 | size_t literal_context_map_size; |
32 | uint32_t* distance_context_map; |
33 | size_t distance_context_map_size; |
34 | HistogramLiteral* literal_histograms; |
35 | size_t literal_histograms_size; |
36 | HistogramCommand* command_histograms; |
37 | size_t command_histograms_size; |
38 | HistogramDistance* distance_histograms; |
39 | size_t distance_histograms_size; |
40 | } MetaBlockSplit; |
41 | |
42 | static BROTLI_INLINE void InitMetaBlockSplit(MetaBlockSplit* mb) { |
43 | BrotliInitBlockSplit(&mb->literal_split); |
44 | BrotliInitBlockSplit(&mb->command_split); |
45 | BrotliInitBlockSplit(&mb->distance_split); |
46 | mb->literal_context_map = 0; |
47 | mb->literal_context_map_size = 0; |
48 | mb->distance_context_map = 0; |
49 | mb->distance_context_map_size = 0; |
50 | mb->literal_histograms = 0; |
51 | mb->literal_histograms_size = 0; |
52 | mb->command_histograms = 0; |
53 | mb->command_histograms_size = 0; |
54 | mb->distance_histograms = 0; |
55 | mb->distance_histograms_size = 0; |
56 | } |
57 | |
58 | static BROTLI_INLINE void DestroyMetaBlockSplit( |
59 | MemoryManager* m, MetaBlockSplit* mb) { |
60 | BrotliDestroyBlockSplit(m, &mb->literal_split); |
61 | BrotliDestroyBlockSplit(m, &mb->command_split); |
62 | BrotliDestroyBlockSplit(m, &mb->distance_split); |
63 | BROTLI_FREE(m, mb->literal_context_map); |
64 | BROTLI_FREE(m, mb->distance_context_map); |
65 | BROTLI_FREE(m, mb->literal_histograms); |
66 | BROTLI_FREE(m, mb->command_histograms); |
67 | BROTLI_FREE(m, mb->distance_histograms); |
68 | } |
69 | |
70 | /* Uses the slow shortest-path block splitter and does context clustering. |
71 | The distance parameters are dynamically selected based on the commands |
72 | which get recomputed under the new distance parameters. The new distance |
73 | parameters are stored into *params. */ |
74 | BROTLI_INTERNAL void BrotliBuildMetaBlock(MemoryManager* m, |
75 | const uint8_t* ringbuffer, |
76 | const size_t pos, |
77 | const size_t mask, |
78 | BrotliEncoderParams* params, |
79 | uint8_t prev_byte, |
80 | uint8_t prev_byte2, |
81 | Command* cmds, |
82 | size_t num_commands, |
83 | ContextType literal_context_mode, |
84 | MetaBlockSplit* mb); |
85 | |
86 | /* Uses a fast greedy block splitter that tries to merge current block with the |
87 | last or the second last block and uses a static context clustering which |
88 | is the same for all block types. */ |
89 | BROTLI_INTERNAL void BrotliBuildMetaBlockGreedy( |
90 | MemoryManager* m, const uint8_t* ringbuffer, size_t pos, size_t mask, |
91 | uint8_t prev_byte, uint8_t prev_byte2, ContextLut literal_context_lut, |
92 | size_t num_contexts, const uint32_t* static_context_map, |
93 | const Command* commands, size_t n_commands, MetaBlockSplit* mb); |
94 | |
95 | BROTLI_INTERNAL void BrotliOptimizeHistograms(uint32_t num_distance_codes, |
96 | MetaBlockSplit* mb); |
97 | |
98 | BROTLI_INTERNAL void BrotliInitDistanceParams(BrotliEncoderParams* params, |
99 | uint32_t npostfix, uint32_t ndirect); |
100 | |
101 | #if defined(__cplusplus) || defined(c_plusplus) |
102 | } /* extern "C" */ |
103 | #endif |
104 | |
105 | #endif /* BROTLI_ENC_METABLOCK_H_ */ |
106 | |