constants.h File Reference

#include "./platform.h"
#include <brotli/port.h>
#include <brotli/types.h>

Go to the source code of this file.

Data Structures
struct	BrotliDistanceCodeLimit
struct	BrotliPrefixCodeRange

Macros
#define	BROTLI_CONTEXT_MAP_MAX_RLE   16
#define	BROTLI_MAX_NUMBER_OF_BLOCK_TYPES   256
#define	BROTLI_NUM_LITERAL_SYMBOLS   256
#define	BROTLI_NUM_COMMAND_SYMBOLS   704
#define	BROTLI_NUM_BLOCK_LEN_SYMBOLS   26
#define	BROTLI_MAX_CONTEXT_MAP_SYMBOLS
#define	BROTLI_MAX_BLOCK_TYPE_SYMBOLS   (BROTLI_MAX_NUMBER_OF_BLOCK_TYPES + 2)
#define	BROTLI_REPEAT_PREVIOUS_CODE_LENGTH   16
#define	BROTLI_REPEAT_ZERO_CODE_LENGTH   17
#define	BROTLI_CODE_LENGTH_CODES   (BROTLI_REPEAT_ZERO_CODE_LENGTH + 1)
#define	BROTLI_INITIAL_REPEATED_CODE_LENGTH   8
#define	BROTLI_LARGE_MAX_DISTANCE_BITS   62U
#define	BROTLI_LARGE_MIN_WBITS   10
#define	BROTLI_LARGE_MAX_WBITS   30
#define	BROTLI_NUM_DISTANCE_SHORT_CODES   16
#define	BROTLI_MAX_NPOSTFIX   3
#define	BROTLI_MAX_NDIRECT   120
#define	BROTLI_MAX_DISTANCE_BITS   24U
#define	BROTLI_DISTANCE_ALPHABET_SIZE(NPOSTFIX, NDIRECT, MAXNBITS)
#define	BROTLI_NUM_DISTANCE_SYMBOLS
#define	BROTLI_MAX_DISTANCE   0x3FFFFFC
#define	BROTLI_MAX_ALLOWED_DISTANCE   0x7FFFFFFC
#define	BROTLI_NUM_INS_COPY_CODES   24
#define	BROTLI_LITERAL_CONTEXT_BITS   6
#define	BROTLI_DISTANCE_CONTEXT_BITS   2
#define	BROTLI_WINDOW_GAP   16
#define	BROTLI_MAX_BACKWARD_LIMIT(W)

Typedefs
typedef struct BrotliDistanceCodeLimit	BrotliDistanceCodeLimit

Functions
BROTLI_UNUSED_FUNCTION BrotliDistanceCodeLimit	BrotliCalculateDistanceCodeLimit (uint32_t max_distance, uint32_t npostfix, uint32_t ndirect)

Variables
BROTLI_COMMON_API const BrotliPrefixCodeRange	_kBrotliPrefixCodeRanges [BROTLI_NUM_BLOCK_LEN_SYMBOLS]

Detailed Description

Common constants used in decoder and encoder API.

Macro Definition Documentation

BROTLI_CODE_LENGTH_CODES

#define BROTLI_CODE_LENGTH_CODES   (BROTLI_REPEAT_ZERO_CODE_LENGTH + 1)

BROTLI_CONTEXT_MAP_MAX_RLE

#define BROTLI_CONTEXT_MAP_MAX_RLE   16

BROTLI_DISTANCE_ALPHABET_SIZE

#define BROTLI_DISTANCE_ALPHABET_SIZE	(		NPOSTFIX,
			NDIRECT,
			MAXNBITS )

Value:

    ( \
    BROTLI_NUM_DISTANCE_SHORT_CODES + (NDIRECT) +                    \
    ((MAXNBITS) << ((NPOSTFIX) + 1)))

BROTLI_DISTANCE_CONTEXT_BITS

#define BROTLI_DISTANCE_CONTEXT_BITS   2

BROTLI_INITIAL_REPEATED_CODE_LENGTH

#define BROTLI_INITIAL_REPEATED_CODE_LENGTH   8

BROTLI_LARGE_MAX_DISTANCE_BITS

#define BROTLI_LARGE_MAX_DISTANCE_BITS   62U

The theoretical maximum number of distance bits specified for large window brotli, for 64-bit encoders and decoders. Even when in practice 32-bit encoders and decoders only support up to 30 max distance bits, the value is set to 62 because it affects the large window brotli file format. Specifically, it affects the encoding of simple huffman tree for distances, see Specification RFC 7932 chapter 3.4.

BROTLI_LARGE_MAX_WBITS

#define BROTLI_LARGE_MAX_WBITS   30

The maximum supported large brotli window bits by the encoder and decoder. Large window brotli allows up to 62 bits, however the current encoder and decoder, designed for 32-bit integers, only support up to 30 bits maximum.

BROTLI_LARGE_MIN_WBITS

#define BROTLI_LARGE_MIN_WBITS   10

BROTLI_LITERAL_CONTEXT_BITS

#define BROTLI_LITERAL_CONTEXT_BITS   6

BROTLI_MAX_ALLOWED_DISTANCE

#define BROTLI_MAX_ALLOWED_DISTANCE   0x7FFFFFFC

BROTLI_MAX_BACKWARD_LIMIT

#define BROTLI_MAX_BACKWARD_LIMIT

(

W

)

Value:

(((size_t)1 << (W)) - BROTLI_WINDOW_GAP)

BROTLI_MAX_BLOCK_TYPE_SYMBOLS

#define BROTLI_MAX_BLOCK_TYPE_SYMBOLS   (BROTLI_MAX_NUMBER_OF_BLOCK_TYPES + 2)

BROTLI_MAX_CONTEXT_MAP_SYMBOLS

#define BROTLI_MAX_CONTEXT_MAP_SYMBOLS

Value:

                                        (BROTLI_MAX_NUMBER_OF_BLOCK_TYPES + \
                                        BROTLI_CONTEXT_MAP_MAX_RLE)

BROTLI_MAX_DISTANCE

#define BROTLI_MAX_DISTANCE   0x3FFFFFC

BROTLI_MAX_DISTANCE_BITS

#define BROTLI_MAX_DISTANCE_BITS   24U

BROTLI_MAX_NDIRECT

#define BROTLI_MAX_NDIRECT   120

BROTLI_MAX_NPOSTFIX

#define BROTLI_MAX_NPOSTFIX   3

Maximal number of "postfix" bits.

Number of "postfix" bits is stored as 2 bits in meta-block header.

BROTLI_MAX_NUMBER_OF_BLOCK_TYPES

#define BROTLI_MAX_NUMBER_OF_BLOCK_TYPES   256

BROTLI_NUM_BLOCK_LEN_SYMBOLS

#define BROTLI_NUM_BLOCK_LEN_SYMBOLS   26

BROTLI_NUM_COMMAND_SYMBOLS

#define BROTLI_NUM_COMMAND_SYMBOLS   704

BROTLI_NUM_DISTANCE_SHORT_CODES

#define BROTLI_NUM_DISTANCE_SHORT_CODES   16

BROTLI_NUM_DISTANCE_SYMBOLS

#define BROTLI_NUM_DISTANCE_SYMBOLS

Value:

    BROTLI_DISTANCE_ALPHABET_SIZE(  \
        BROTLI_MAX_NDIRECT, BROTLI_MAX_NPOSTFIX, BROTLI_LARGE_MAX_DISTANCE_BITS)

BROTLI_NUM_INS_COPY_CODES

#define BROTLI_NUM_INS_COPY_CODES   24

BROTLI_NUM_LITERAL_SYMBOLS

#define BROTLI_NUM_LITERAL_SYMBOLS   256

BROTLI_REPEAT_PREVIOUS_CODE_LENGTH

#define BROTLI_REPEAT_PREVIOUS_CODE_LENGTH   16

BROTLI_REPEAT_ZERO_CODE_LENGTH

#define BROTLI_REPEAT_ZERO_CODE_LENGTH   17

BROTLI_WINDOW_GAP

#define BROTLI_WINDOW_GAP   16

Typedef Documentation

BrotliDistanceCodeLimit

typedef struct BrotliDistanceCodeLimit BrotliDistanceCodeLimit

Function Documentation

BrotliCalculateDistanceCodeLimit()

BROTLI_UNUSED_FUNCTION BrotliDistanceCodeLimit BrotliCalculateDistanceCodeLimit	(	uint32_t	max_distance,
		uint32_t	npostfix,
		uint32_t	ndirect )

Variable Documentation

_kBrotliPrefixCodeRanges

BROTLI_COMMON_API const BrotliPrefixCodeRange _kBrotliPrefixCodeRanges[BROTLI_NUM_BLOCK_LEN_SYMBOLS]

extern