brotli/c/enc/histogram.h
Eugene Kliuchnikov 35e69fc7cf
New feature: "Large Window Brotli" (#640)
* New feature: "Large Window Brotli"

By setting special encoder/decoder flag it is now possible to extend
LZ-window up to 30 bits; though produced stream will not be RFC7932
compliant.

Added new dictionary generator - "DSH". It combines speed of "Sieve"
and quality of "DM". Plus utilities to prepare train corpora
(remove unique strings).

Improved compression ratio: now two sub-blocks could be stitched:
the last copy command could be extended to span the next sub-block.

Fixed compression ineffectiveness caused by floating numbers rounding and
wrong cost heuristic.

Other C changes:
 - combined / moved `context.h` to `common`
 - moved transforms to `common`
 - unified some aspects of code formatting
 - added an abstraction for encoder (static) dictionary
 - moved default allocator/deallocator functions to `common`

brotli CLI:
 - window size is auto-adjusted if not specified explicitly

Java:
 - added "eager" decoding both to JNI wrapper and pure decoder
 - huge speed-up of `DictionaryData` initialization

* Add dictionaryless compressed dictionary

* Fix `sources.lst`

* Fix `sources.lst` and add a note that `libtool` is also required.

* Update setup.py

* Fix `EagerStreamTest`

* Fix BUILD file

* Add missing `libdivsufsort` dependency

* Fix "unused parameter" warning.
2018-02-26 09:04:36 -05:00

64 lines
1.8 KiB
C

/* Copyright 2013 Google Inc. All Rights Reserved.
Distributed under MIT license.
See file LICENSE for detail or copy at https://opensource.org/licenses/MIT
*/
/* Models the histograms of literals, commands and distance codes. */
#ifndef BROTLI_ENC_HISTOGRAM_H_
#define BROTLI_ENC_HISTOGRAM_H_
#include <string.h> /* memset */
#include "../common/constants.h"
#include "../common/context.h"
#include "../common/platform.h"
#include <brotli/types.h>
#include "./block_splitter.h"
#include "./command.h"
#if defined(__cplusplus) || defined(c_plusplus)
extern "C" {
#endif
/* The distance symbols effectively used by "Large Window Brotli" (32-bit). */
#define BROTLI_NUM_HISTOGRAM_DISTANCE_SYMBOLS 544
#define FN(X) X ## Literal
#define DATA_SIZE BROTLI_NUM_LITERAL_SYMBOLS
#define DataType uint8_t
#include "./histogram_inc.h" /* NOLINT(build/include) */
#undef DataType
#undef DATA_SIZE
#undef FN
#define FN(X) X ## Command
#define DataType uint16_t
#define DATA_SIZE BROTLI_NUM_COMMAND_SYMBOLS
#include "./histogram_inc.h" /* NOLINT(build/include) */
#undef DATA_SIZE
#undef FN
#define FN(X) X ## Distance
#define DATA_SIZE BROTLI_NUM_HISTOGRAM_DISTANCE_SYMBOLS
#include "./histogram_inc.h" /* NOLINT(build/include) */
#undef DataType
#undef DATA_SIZE
#undef FN
BROTLI_INTERNAL void BrotliBuildHistogramsWithContext(
const Command* cmds, const size_t num_commands,
const BlockSplit* literal_split, const BlockSplit* insert_and_copy_split,
const BlockSplit* dist_split, const uint8_t* ringbuffer, size_t pos,
size_t mask, uint8_t prev_byte, uint8_t prev_byte2,
const ContextType* context_modes, HistogramLiteral* literal_histograms,
HistogramCommand* insert_and_copy_histograms,
HistogramDistance* copy_dist_histograms);
#if defined(__cplusplus) || defined(c_plusplus)
} /* extern "C" */
#endif
#endif /* BROTLI_ENC_HISTOGRAM_H_ */