brotli/c/enc/static_dict.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

41 lines
1.2 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
*/
/* Class to model the static dictionary. */
#ifndef BROTLI_ENC_STATIC_DICT_H_
#define BROTLI_ENC_STATIC_DICT_H_
#include "../common/dictionary.h"
#include "../common/platform.h"
#include <brotli/types.h>
#include "./encoder_dict.h"
#if defined(__cplusplus) || defined(c_plusplus)
extern "C" {
#endif
#define BROTLI_MAX_STATIC_DICTIONARY_MATCH_LEN 37
static const uint32_t kInvalidMatch = 0xFFFFFFF;
/* Matches data against static dictionary words, and for each length l,
for which a match is found, updates matches[l] to be the minimum possible
(distance << 5) + len_code.
Returns 1 if matches have been found, otherwise 0.
Prerequisites:
matches array is at least BROTLI_MAX_STATIC_DICTIONARY_MATCH_LEN + 1 long
all elements are initialized to kInvalidMatch */
BROTLI_INTERNAL BROTLI_BOOL BrotliFindAllStaticDictionaryMatches(
const BrotliEncoderDictionary* dictionary,
const uint8_t* data, size_t min_length, size_t max_length,
uint32_t* matches);
#if defined(__cplusplus) || defined(c_plusplus)
} /* extern "C" */
#endif
#endif /* BROTLI_ENC_STATIC_DICT_H_ */