Burger::GIFDecoder Class Reference

GIF style LZW decompresser. More...

Collaboration diagram for Burger::GIFDecoder:

Public Member Functions
	GIFDecoder ()
	Initialize a GIFDecoder.
const char *	Unpack (uint8_t *pOutput, uintptr_t uOutputLength, InputMemoryStream *pInput)
	Decompress the image.

Static Public Member Functions
static GIFDecoder *	New (void)
	Allocate and initialize a GIFDecoder.

Private Member Functions
void	Init (void)
	Init the LZW permanent tokens.
void	Reset (void)
	Reset the LZW token tree.
uint_t	GetCode (uint_t uBitsRequested)
	Get an LZW code token.

Private Attributes
InputMemoryStream *	m_pInput
	Pointer to packed data.
uint_t	m_uBitBucket
	Current bit bucket.
uint_t	m_uBitCount
	Current valid bit count in bucket.
uint_t	m_uChunkCount
	Number of bytes in stream.
uint_t	m_uLZWCodeSize
	Starting data size.
const uint8_t *	m_LZWTable [4096]
	Dictionary pointers.
uint8_t	m_LZWArray [256]
	0-255 for default data
uint_t	m_LZWSize [4096]
	Size of each entry.

Detailed Description

GIF style LZW decompresser.

---

This class will decompress LZW data in the GIF format

See also

FileGIF or GIFEncoder

Constructor & Destructor Documentation

GIFDecoder()

Burger::GIFDecoder::GIFDecoder

(

)

Initialize a GIFDecoder.

---

Member Function Documentation

GetCode()

uint_t Burger::GIFDecoder::GetCode ( uint_t uBitsRequested )

private

Get an LZW code token.

---

Parameters

uBitsRequested

Number of bits to pull from the byte stream

Returns

Value pulled from the bit stream (Zero if data is depleted)

Init()

void Burger::GIFDecoder::Init ( void )

private

Init the LZW permanent tokens.

---

New()

Burger::GIFDecoder *BURGER_API Burger::GIFDecoder::New ( void )

static

Allocate and initialize a GIFDecoder.

---

Returns

A pointer to a default GIFDecoder class or NULL if out of memory

See also

Delete(const T *)

Reset()

void Burger::GIFDecoder::Reset ( void )

private

Reset the LZW token tree.

---

Unpack()

const char * Burger::GIFDecoder::Unpack	(	uint8_t *	pOutput,
		uintptr_t	uOutputLength,
		InputMemoryStream *	pInput )

Decompress the image.

---

Decompress the LZW compressed image data into a linear buffer

Parameters

pOutput	Buffer to accept the decompressed data
uOutputLength	Length of the buffer for decompressed data
pInput	Data stream to read compressed data from

Returns

NULL if success or a pointer to a string describing the error

Member Data Documentation

m_LZWArray

uint8_t Burger::GIFDecoder::m_LZWArray[256]

private

0-255 for default data

m_LZWSize

uint_t Burger::GIFDecoder::m_LZWSize[4096]

private

Size of each entry.

m_LZWTable

const uint8_t* Burger::GIFDecoder::m_LZWTable[4096]

private

Dictionary pointers.

m_pInput

InputMemoryStream* Burger::GIFDecoder::m_pInput

private

Pointer to packed data.

m_uBitBucket

uint_t Burger::GIFDecoder::m_uBitBucket

private

Current bit bucket.

m_uBitCount

uint_t Burger::GIFDecoder::m_uBitCount

private

Current valid bit count in bucket.

m_uChunkCount

uint_t Burger::GIFDecoder::m_uChunkCount

private

Number of bytes in stream.

m_uLZWCodeSize

uint_t Burger::GIFDecoder::m_uLZWCodeSize

private

Starting data size.