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author | Matt A. Tobin <email@mattatobin.com> | 2019-11-14 21:08:43 -0500 |
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committer | Matt A. Tobin <email@mattatobin.com> | 2019-11-14 21:08:43 -0500 |
commit | 1d30f6fa8413746ddc408f93710d701493af273d (patch) | |
tree | abe84e83d704e13c60c90db7ac4b9e363d8a81fc /modules/brotli/enc/backward_references_hq.h | |
parent | 9308ec68e863e4c6e650680370a5d7baa9f0d1f3 (diff) | |
parent | 00573571a226a0c59dd744da67483864a22911aa (diff) | |
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Merge branch 'master' into mailnews-work
Diffstat (limited to 'modules/brotli/enc/backward_references_hq.h')
-rw-r--r-- | modules/brotli/enc/backward_references_hq.h | 92 |
1 files changed, 92 insertions, 0 deletions
diff --git a/modules/brotli/enc/backward_references_hq.h b/modules/brotli/enc/backward_references_hq.h new file mode 100644 index 000000000..1e4275d40 --- /dev/null +++ b/modules/brotli/enc/backward_references_hq.h @@ -0,0 +1,92 @@ +/* Copyright 2013 Google Inc. All Rights Reserved. + + Distributed under MIT license. + See file LICENSE for detail or copy at https://opensource.org/licenses/MIT +*/ + +/* Function to find backward reference copies. */ + +#ifndef BROTLI_ENC_BACKWARD_REFERENCES_HQ_H_ +#define BROTLI_ENC_BACKWARD_REFERENCES_HQ_H_ + +#include "../common/constants.h" +#include "../common/dictionary.h" +#include "../common/platform.h" +#include <brotli/types.h> +#include "./command.h" +#include "./hash.h" +#include "./memory.h" +#include "./quality.h" + +#if defined(__cplusplus) || defined(c_plusplus) +extern "C" { +#endif + +BROTLI_INTERNAL void BrotliCreateZopfliBackwardReferences(MemoryManager* m, + size_t num_bytes, size_t position, const uint8_t* ringbuffer, + size_t ringbuffer_mask, const BrotliEncoderParams* params, + HasherHandle hasher, int* dist_cache, size_t* last_insert_len, + Command* commands, size_t* num_commands, size_t* num_literals); + +BROTLI_INTERNAL void BrotliCreateHqZopfliBackwardReferences(MemoryManager* m, + size_t num_bytes, size_t position, const uint8_t* ringbuffer, + size_t ringbuffer_mask, const BrotliEncoderParams* params, + HasherHandle hasher, int* dist_cache, size_t* last_insert_len, + Command* commands, size_t* num_commands, size_t* num_literals); + +typedef struct ZopfliNode { + /* Best length to get up to this byte (not including this byte itself) + highest 7 bit is used to reconstruct the length code. */ + uint32_t length; + /* Distance associated with the length. */ + uint32_t distance; + /* Number of literal inserts before this copy; highest 5 bits contain + distance short code + 1 (or zero if no short code). */ + uint32_t dcode_insert_length; + + /* This union holds information used by dynamic-programming. During forward + pass |cost| it used to store the goal function. When node is processed its + |cost| is invalidated in favor of |shortcut|. On path back-tracing pass + |next| is assigned the offset to next node on the path. */ + union { + /* Smallest cost to get to this byte from the beginning, as found so far. */ + float cost; + /* Offset to the next node on the path. Equals to command_length() of the + next node on the path. For last node equals to BROTLI_UINT32_MAX */ + uint32_t next; + /* Node position that provides next distance for distance cache. */ + uint32_t shortcut; + } u; +} ZopfliNode; + +BROTLI_INTERNAL void BrotliInitZopfliNodes(ZopfliNode* array, size_t length); + +/* Computes the shortest path of commands from position to at most + position + num_bytes. + + On return, path->size() is the number of commands found and path[i] is the + length of the i-th command (copy length plus insert length). + Note that the sum of the lengths of all commands can be less than num_bytes. + + On return, the nodes[0..num_bytes] array will have the following + "ZopfliNode array invariant": + For each i in [1..num_bytes], if nodes[i].cost < kInfinity, then + (1) nodes[i].copy_length() >= 2 + (2) nodes[i].command_length() <= i and + (3) nodes[i - nodes[i].command_length()].cost < kInfinity */ +BROTLI_INTERNAL size_t BrotliZopfliComputeShortestPath( + MemoryManager* m, size_t num_bytes, + size_t position, const uint8_t* ringbuffer, size_t ringbuffer_mask, + const BrotliEncoderParams* params, + const int* dist_cache, HasherHandle hasher, ZopfliNode* nodes); + +BROTLI_INTERNAL void BrotliZopfliCreateCommands( + const size_t num_bytes, const size_t block_start, const ZopfliNode* nodes, + int* dist_cache, size_t* last_insert_len, const BrotliEncoderParams* params, + Command* commands, size_t* num_literals); + +#if defined(__cplusplus) || defined(c_plusplus) +} /* extern "C" */ +#endif + +#endif /* BROTLI_ENC_BACKWARD_REFERENCES_HQ_H_ */ |