Burger::CompressILBMRLE Class Reference

Compress data using ILBM Run Length Encoding. More...

Inheritance diagram for Burger::CompressILBMRLE:

Collaboration diagram for Burger::CompressILBMRLE:

Public Member Functions
const Burger::StaticRTTI *	get_StaticRTTI (void) const noexcept override
	Get the description to the class.
	CompressILBMRLE (void)
	Default constructor.
eError	Init (void) override
	Reset the RLE compressor.
eError	Process (const void *pInput, uintptr_t uInputLength) override
	Compress the input data using RLE.
eError	Finalize (void) override
	Finalize RLE compression.
Public Member Functions inherited from Burger::Compress
	Compress (void)
	Default constructor.
virtual	~Compress ()
	Default destructor.
OutputMemoryStream *	GetOutput (void) noexcept
	Get the output data.
uintptr_t	GetOutputSize (void) const noexcept
	Get the output data size in bytes.
uint32_t	GetSignature (void) const noexcept
	Return the signature for this compressor.
Public Member Functions inherited from Burger::Base
const char *	get_class_name (void) const noexcept
	Get the name of the class.
virtual	~Base () noexcept=default
	Destructor.

Static Public Attributes
static const Burger::StaticRTTI	g_StaticRTTI
	The global description of the class.
static const uint32_t	Signature = 0x524C4420
	'RLE '
Static Public Attributes inherited from Burger::Compress
static const Burger::StaticRTTI	g_StaticRTTI
	The global description of the class.
Static Public Attributes inherited from Burger::Base
static const Burger::StaticRTTI	g_StaticRTTI
	The global description of the class.

Protected Member Functions
eError	Compact (const uint8_t *pInput, uintptr_t uInputLength)
	Compress the input data using RLE.

Protected Attributes
uintptr_t	m_uCacheUsed
	Number of bytes in the cache.
uintptr_t	m_uRemaining
	Number of bytes unprocessed from the last call to Compact()
uint8_t	m_Cache [128+8]
	Data cache for resuming compression.
Protected Attributes inherited from Burger::Compress
OutputMemoryStream	m_Output
	Main output buffer for compressed data.
uint32_t	m_uSignature
	4 character code to identify this compressor

Detailed Description

Compress data using ILBM Run Length Encoding.

---

This simple format encodes a data stream by finding runs of duplicated data and encodes the duplicates into a count/byte pair. Otherwise, it's a count followed by a stream of raw data.

The format is as follows, a byte is taken which is either above 128 or less than 128. If higher than 128, it's a repeater, if less than 128, it's a count.

128 is considered a "No Operation" or end of line for the data stream. As such, 128 is not allowed to be encoded.

uint8_t uToken = pDataStream[0];
if (uToken>128) {
    uint_t uCount = 257-uToken;
    MemoryFill(pOutput,pDataStream[1],uCount);
    pDataStream+=2;
} else if (uToken<128) {
    uint_t uCount = uToken+1;
    MemoryCopy(pOutput,pDataStream+1,uCount);
    pDataStream+=uCount+1;
} else if (uToken==128) {
    // Do nothing, as per ILBM specifications
}

See also

Burger::DecompressILBMRLE

Constructor & Destructor Documentation

CompressILBMRLE()

Burger::CompressILBMRLE::CompressILBMRLE

(

void

)

Default constructor.

---

Initializes the cache buffer.

Member Function Documentation

Compact()

Burger::eError Burger::CompressILBMRLE::Compact ( const uint8_t * pInput, uintptr_t uInputLength )

protected

Compress the input data using RLE.

---

Compresses the data using RLE and stores the compressed data into an OutputMemoryStream. If there is any excess data, record the size in CompressILBMRLE::m_uRemaining

Finalize()

Burger::eError Burger::CompressILBMRLE::Finalize ( void )

overridevirtual

Finalize RLE compression.

---

If any data has been cached from the compression stream, flush it into the output

Returns

Zero if no error, non-zero on error

Implements Burger::Compress.

get_StaticRTTI()

const Burger::StaticRTTI * Burger::CompressILBMRLE::get_StaticRTTI ( void ) const

overridevirtualnoexcept

Get the description to the class.

---

This virtual function will pull the pointer to the StaticRTTI instance that has the name of the class. Due to it being virtual, it will be the name of the most derived class.

Returns

Pointer to a global, read only instance of StaticRTTI for the true class

Reimplemented from Burger::Compress.

Init()

Burger::eError Burger::CompressILBMRLE::Init ( void )

overridevirtual

Reset the RLE compressor.

---

Resets the cache buffer.

Implements Burger::Compress.

Process()

Burger::eError Burger::CompressILBMRLE::Process ( const void * pInput, uintptr_t uInputLength )

overridevirtual

Compress the input data using RLE.

---

Compresses the data using RLE and stores the compressed data into an OutputMemoryStream

Implements Burger::Compress.

Member Data Documentation

g_StaticRTTI

const Burger::StaticRTTI Burger::CompressILBMRLE::g_StaticRTTI

static

The global description of the class.

---

This record contains the name of this class and a reference to the parent

m_Cache

uint8_t Burger::CompressILBMRLE::m_Cache[128+8]

protected

Data cache for resuming compression.

m_uCacheUsed

uintptr_t Burger::CompressILBMRLE::m_uCacheUsed

protected

Number of bytes in the cache.

m_uRemaining

uintptr_t Burger::CompressILBMRLE::m_uRemaining

protected

Number of bytes unprocessed from the last call to Compact()

Signature

const uint32_t Burger::CompressILBMRLE::Signature = 0x524C4420

static

'RLE '