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| author | Eugene Kliuchnikov <eustas@google.com> | 2018-02-26 09:04:36 -0500 |
|---|---|---|
| committer | GitHub <noreply@github.com> | 2018-02-26 09:04:36 -0500 |
| commit | 35e69fc7cf9421ab04ffc9d52cb36d07fa12984a (patch) | |
| tree | a1ed614391936d455da2b0610ef8e8caf88b4289 /c/common/constants.h | |
| parent | 3af18990f50d8f040038aaa08c41f5d27d62efb5 (diff) | |
| download | brotli-35e69fc7cf9421ab04ffc9d52cb36d07fa12984a.tar.gz | |
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.
Diffstat (limited to 'c/common/constants.h')
| -rw-r--r-- | c/common/constants.h | 19 |
1 files changed, 13 insertions, 6 deletions
diff --git a/c/common/constants.h b/c/common/constants.h index 416ec55..26edcd5 100644 --- a/c/common/constants.h +++ b/c/common/constants.h @@ -28,18 +28,25 @@ /* "code length of 8 is repeated" */ #define BROTLI_INITIAL_REPEATED_CODE_LENGTH 8 +/* "Large Window Brotli" */ +#define BROTLI_LARGE_MAX_DISTANCE_BITS 62U +#define BROTLI_LARGE_MIN_WBITS 10 +#define BROTLI_LARGE_MAX_WBITS 30 + /* Specification: 4. Encoding of distances */ #define BROTLI_NUM_DISTANCE_SHORT_CODES 16 #define BROTLI_MAX_NPOSTFIX 3 #define BROTLI_MAX_NDIRECT 120 #define BROTLI_MAX_DISTANCE_BITS 24U -/* BROTLI_NUM_DISTANCE_SYMBOLS == 520 */ -#define BROTLI_NUM_DISTANCE_SYMBOLS (BROTLI_NUM_DISTANCE_SHORT_CODES + \ - BROTLI_MAX_NDIRECT + \ - (BROTLI_MAX_DISTANCE_BITS << \ - (BROTLI_MAX_NPOSTFIX + 1))) -/* Distance that is guaranteed to be representable in any stream. */ +#define BROTLI_DISTANCE_ALPHABET_SIZE(NDIRECT, NPOSTFIX, MAXNBITS) ( \ + BROTLI_NUM_DISTANCE_SHORT_CODES + (NDIRECT) + \ + ((MAXNBITS) << ((NPOSTFIX) + 1))) +/* BROTLI_NUM_DISTANCE_SYMBOLS == 1128 */ +#define BROTLI_NUM_DISTANCE_SYMBOLS \ + BROTLI_DISTANCE_ALPHABET_SIZE( \ + BROTLI_MAX_NDIRECT, BROTLI_MAX_NPOSTFIX, BROTLI_LARGE_MAX_DISTANCE_BITS) #define BROTLI_MAX_DISTANCE 0x3FFFFFC +#define BROTLI_MAX_ALLOWED_DISTANCE 0x7FFFFFFC /* 7.1. Context modes and context ID lookup for literals */ /* "context IDs for literals are in the range of 0..63" */ |