bitstream.h File Reference

#include "mem.h"
#include "compiler.h"
#include "debug.h"
#include "error_private.h"
#include "bits.h"

Go to the source code of this file.

Data Structures
struct	BIT_CStream_t
struct	BIT_DStream_t

Macros
#define	STREAM_ACCUMULATOR_MIN_32   25
#define	STREAM_ACCUMULATOR_MIN_64   57
#define	STREAM_ACCUMULATOR_MIN   ((U32)(MEM_32bits() ? STREAM_ACCUMULATOR_MIN_32 : STREAM_ACCUMULATOR_MIN_64))
#define	BIT_MASK_SIZE   (sizeof(BIT_mask) / sizeof(BIT_mask[0]))

Typedefs
typedef size_t	BitContainerType

Enumerations
enum	BIT_DStream_status { BIT_DStream_unfinished = 0 , BIT_DStream_endOfBuffer = 1 , BIT_DStream_completed = 2 , BIT_DStream_overflow = 3 }

Functions
MEM_STATIC size_t	BIT_initCStream (BIT_CStream_t *bitC, void *dstBuffer, size_t dstCapacity)
MEM_STATIC void	BIT_addBits (BIT_CStream_t *bitC, size_t value, unsigned nbBits)
MEM_STATIC void	BIT_flushBits (BIT_CStream_t *bitC)
MEM_STATIC size_t	BIT_closeCStream (BIT_CStream_t *bitC)
MEM_STATIC size_t	BIT_initDStream (BIT_DStream_t *bitD, const void *srcBuffer, size_t srcSize)
MEM_STATIC size_t	BIT_readBits (BIT_DStream_t *bitD, unsigned nbBits)
MEM_STATIC BIT_DStream_status	BIT_reloadDStream (BIT_DStream_t *bitD)
MEM_STATIC unsigned	BIT_endOfDStream (const BIT_DStream_t *bitD)
MEM_STATIC void	BIT_addBitsFast (BIT_CStream_t *bitC, size_t value, unsigned nbBits)
MEM_STATIC void	BIT_flushBitsFast (BIT_CStream_t *bitC)
MEM_STATIC size_t	BIT_readBitsFast (BIT_DStream_t *bitD, unsigned nbBits)
FORCE_INLINE_TEMPLATE size_t	BIT_getLowerBits (size_t bitContainer, U32 const nbBits)
FORCE_INLINE_TEMPLATE size_t	BIT_getUpperBits (BitContainerType bitContainer, U32 const start)
FORCE_INLINE_TEMPLATE size_t	BIT_getMiddleBits (BitContainerType bitContainer, U32 const start, U32 const nbBits)
FORCE_INLINE_TEMPLATE size_t	BIT_lookBits (const BIT_DStream_t *bitD, U32 nbBits)
MEM_STATIC size_t	BIT_lookBitsFast (const BIT_DStream_t *bitD, U32 nbBits)
FORCE_INLINE_TEMPLATE void	BIT_skipBits (BIT_DStream_t *bitD, U32 nbBits)
MEM_STATIC BIT_DStream_status	BIT_reloadDStream_internal (BIT_DStream_t *bitD)
MEM_STATIC BIT_DStream_status	BIT_reloadDStreamFast (BIT_DStream_t *bitD)

Macro Definition Documentation

BIT_MASK_SIZE

#define BIT_MASK_SIZE   (sizeof(BIT_mask) / sizeof(BIT_mask[0]))

STREAM_ACCUMULATOR_MIN

#define STREAM_ACCUMULATOR_MIN   ((U32)(MEM_32bits() ? STREAM_ACCUMULATOR_MIN_32 : STREAM_ACCUMULATOR_MIN_64))

STREAM_ACCUMULATOR_MIN_32

#define STREAM_ACCUMULATOR_MIN_32   25

STREAM_ACCUMULATOR_MIN_64

#define STREAM_ACCUMULATOR_MIN_64   57

Typedef Documentation

BitContainerType

typedef size_t BitContainerType

Enumeration Type Documentation

BIT_DStream_status

enum BIT_DStream_status

Enumerator
BIT_DStream_unfinished
BIT_DStream_endOfBuffer
BIT_DStream_completed
BIT_DStream_overflow

Function Documentation

BIT_addBits()

MEM_STATIC void BIT_addBits	(	BIT_CStream_t *	bitC,
		size_t	value,
		unsigned	nbBits )

BIT_addBits() : can add up to 31 bits into bitC. Note : does not check for register overflow !

BIT_addBitsFast()

MEM_STATIC void BIT_addBitsFast	(	BIT_CStream_t *	bitC,
		size_t	value,
		unsigned	nbBits )

BIT_addBitsFast() : works only if value is clean, meaning all high bits above nbBits are 0

BIT_closeCStream()

MEM_STATIC size_t BIT_closeCStream

(

BIT_CStream_t *

bitC

)

BIT_closeCStream() :

Returns

: size of CStream, in bytes, or 0 if it could not fit into dstBuffer

BIT_endOfDStream()

MEM_STATIC unsigned BIT_endOfDStream

(

const BIT_DStream_t *

DStream

)

BIT_endOfDStream() :

Returns

: 1 if DStream has exactly reached its end (all bits consumed).

BIT_flushBits()

MEM_STATIC void BIT_flushBits

(

BIT_CStream_t *

bitC

)

BIT_flushBits() : assumption : bitContainer has not overflowed safe version; check for buffer overflow, and prevents it. note : does not signal buffer overflow. overflow will be revealed later on using BIT_closeCStream()

BIT_flushBitsFast()

MEM_STATIC void BIT_flushBitsFast

(

BIT_CStream_t *

bitC

)

BIT_flushBitsFast() : assumption : bitContainer has not overflowed unsafe version; does not check buffer overflow

BIT_getLowerBits()

FORCE_INLINE_TEMPLATE size_t BIT_getLowerBits	(	size_t	bitContainer,
		U32 const	nbBits )

BIT_getMiddleBits()

FORCE_INLINE_TEMPLATE size_t BIT_getMiddleBits	(	BitContainerType	bitContainer,
		U32 const	start,
		U32 const	nbBits )

BIT_getUpperBits()

FORCE_INLINE_TEMPLATE size_t BIT_getUpperBits	(	BitContainerType	bitContainer,
		U32 const	start )

BIT_initCStream()

MEM_STATIC size_t BIT_initCStream	(	BIT_CStream_t *	bitC,
		void *	startPtr,
		size_t	dstCapacity )

BIT_initCStream() : dstCapacity must be > sizeof(size_t)

Returns

: 0 if success, otherwise an error code (can be tested using ERR_isError())

BIT_initDStream()

MEM_STATIC size_t BIT_initDStream	(	BIT_DStream_t *	bitD,
		const void *	srcBuffer,
		size_t	srcSize )

BIT_initDStream() : Initialize a BIT_DStream_t. bitD : a pointer to an already allocated BIT_DStream_t structure. srcSize must be the exact size of the bitStream, in bytes.

Returns

: size of stream (== srcSize), or an errorCode if a problem is detected

BIT_lookBits()

FORCE_INLINE_TEMPLATE size_t BIT_lookBits	(	const BIT_DStream_t *	bitD,
		U32	nbBits )

BIT_lookBits() : Provides next n bits from local register. local register is not modified. On 32-bits, maxNbBits==24. On 64-bits, maxNbBits==56.

Returns

: value extracted

BIT_lookBitsFast()

MEM_STATIC size_t BIT_lookBitsFast	(	const BIT_DStream_t *	bitD,
		U32	nbBits )

BIT_lookBitsFast() : unsafe version; only works if nbBits >= 1

BIT_readBits()

MEM_STATIC size_t BIT_readBits	(	BIT_DStream_t *	bitD,
		unsigned	nbBits )

BIT_readBits() : Read (consume) next n bits from local register and update. Pay attention to not read more than nbBits contained into local register.

Returns

: extracted value.

BIT_readBitsFast()

MEM_STATIC size_t BIT_readBitsFast	(	BIT_DStream_t *	bitD,
		unsigned	nbBits )

BIT_readBitsFast() : unsafe version; only works if nbBits >= 1

BIT_reloadDStream()

MEM_STATIC BIT_DStream_status BIT_reloadDStream

(

BIT_DStream_t *

bitD

)

BIT_reloadDStream() : Refill bitD from buffer previously set in BIT_initDStream() . This function is safe, it guarantees it will not never beyond src buffer.

Returns

: status of BIT_DStream_t internal register. when status == BIT_DStream_unfinished, internal register is filled with at least 25 or 57 bits

BIT_reloadDStream_internal()

MEM_STATIC BIT_DStream_status BIT_reloadDStream_internal

(

BIT_DStream_t *

bitD

)

BIT_reloadDStream_internal() : Simple variant of BIT_reloadDStream(), with two conditions:

1. bitstream is valid : bitsConsumed <= sizeof(bitD->bitContainer)*8
2. look window is valid after shifted down : bitD->ptr >= bitD->start

BIT_reloadDStreamFast()

MEM_STATIC BIT_DStream_status BIT_reloadDStreamFast

(

BIT_DStream_t *

bitD

)

BIT_reloadDStreamFast() : Similar to BIT_reloadDStream(), but with two differences:

1. bitsConsumed <= sizeof(bitD->bitContainer)*8 must hold!
2. Returns BIT_DStream_overflow when bitD->ptr < bitD->limitPtr, at this point you must use BIT_reloadDStream() to reload.

BIT_skipBits()

FORCE_INLINE_TEMPLATE void BIT_skipBits	(	BIT_DStream_t *	bitD,
		U32	nbBits )