IO Handler for Isis Cubes using the BSQ format. More...

#include <CubeBsqHandler.h>

Public Member Functions
	CubeBsqHandler (QFile dataFile, const QList< int > virtualBandList, const Pvl &label, bool alreadyOnDisk)
	Construct a BSQ IO handler.
	~CubeBsqHandler ()
	The destructor writes all cached data to disk.
void	updateLabels (Pvl &labels)
	Children should probably implement this method.
void	read (Buffer &bufferToFill) const
	Read cube data from disk into the buffer.
void	write (const Buffer &bufferToWrite)
	Write buffer data into the cube data on disk.
void	addCachingAlgorithm (CubeCachingAlgorithm *algorithm)
	This will add the given caching algorithm to the list of attempted caching algorithms.
void	clearCache (bool blockForWriteCache=true) const
	Free all cube chunks (cached cube data) from memory and write them to disk.
BigInt	getDataSize () const
void	setVirtualBands (const QList< int > *virtualBandList)
	This changes the virtual band list.
QMutex *	dataFileMutex ()
	Get the mutex that this IO handler is using around I/Os on the given data file.

Protected Member Functions
virtual void	readRaw (RawCubeChunk &chunkToFill)
	This needs to populate the chunkToFill with unswapped raw bytes from the disk.
virtual void	writeRaw (const RawCubeChunk &chunkToWrite)
	This needs to write the chunkToWrite directly to disk with no modifications to the data itself.
int	bandCount () const
int	getBandCountInChunk () const
BigInt	getBytesPerChunk () const
int	getChunkCountInBandDimension () const
int	getChunkCountInLineDimension () const
int	getChunkCountInSampleDimension () const
int	getChunkIndex (const RawCubeChunk &) const
	Given a chunk, what's its index in the file.
BigInt	getDataStartByte () const
QFile *	getDataFile ()
int	lineCount () const
int	getLineCountInChunk () const
PixelType	pixelType () const
int	sampleCount () const
int	getSampleCountInChunk () const
void	setChunkSizes (int numSamples, int numLines, int numBands)
	This should be called once from the child constructor.

Detailed Description

IO Handler for Isis Cubes using the BSQ format.

This class is used to open, create, read, and write data from Isis cube files.

Author: 2003-02-14 Jeff Anderson

Constructor & Destructor Documentation

Isis::CubeBsqHandler::CubeBsqHandler	(	QFile *	dataFile,
		const QList< int > *	virtualBandList,
		const Pvl &	labels,
		bool	alreadyOnDisk
	)

Construct a BSQ IO handler.

This will determine a good chunk size to use that does not result in the cube being enlarged or misordered.

Parameters

dataFile	The file with cube DN data in it
virtualBandList	The mapping from virtual band to physical band, see CubeIoHandler's description.
labels	The Pvl labels for the cube
alreadyOnDisk	True if the cube is allocated on the disk, false otherwise

References Isis::CubeIoHandler::lineCount(), Isis::CubeIoHandler::pixelType(), Isis::CubeIoHandler::sampleCount(), Isis::CubeIoHandler::setChunkSizes(), and Isis::SizeOf().

Isis::CubeBsqHandler::~CubeBsqHandler ( )

The destructor writes all cached data to disk.

References Isis::CubeIoHandler::clearCache().

Member Function Documentation

void Isis::CubeIoHandler::addCachingAlgorithm ( CubeCachingAlgorithm * algorithm )

inherited

This will add the given caching algorithm to the list of attempted caching algorithms.

The algorithms are tried in the opposite order that they were added - the first algorithm added is the last algorithm tried.

This method takes ownership of algorithm.

Parameters

algorithm The caching algorithm to add to the Cube for I/O

int Isis::CubeIoHandler::bandCount ( ) const

protectedinherited

Returns: the number of physical bands in the cube.

void Isis::CubeIoHandler::clearCache ( bool blockForWriteCache = true ) const

inherited

Free all cube chunks (cached cube data) from memory and write them to disk.

Child destructors need to call this method.

This method should only be called otherwise when lots of cubes are in memory and the many caches cause problems with system RAM limitations.

Parameters

blockForWriteCache This should be true unless this method is called from the write thread.

Referenced by ~CubeBsqHandler(), and Isis::CubeTileHandler::~CubeTileHandler().

QMutex * Isis::CubeIoHandler::dataFileMutex ( )

inherited

Get the mutex that this IO handler is using around I/Os on the given data file.

A lock should be acquired before doing any reads/writes on the data file externally.

Returns: A mutex that can guarantee exclusive access to the data file

int Isis::CubeIoHandler::getBandCountInChunk ( ) const

protectedinherited

Returns: the number of bands per chunk for this cube.

BigInt Isis::CubeIoHandler::getBytesPerChunk ( ) const

protectedinherited

Returns: the byte size of each chunk in the cube. Currently they must be constant size, but this is planned to be changed at some point in time.; Number of bytes in a cube chunk

References Isis::SizeOf().

int Isis::CubeIoHandler::getChunkCountInBandDimension ( ) const

protectedinherited

Returns: the total number of chunks in the band (Z) dimension. This is always enough to contain every band in the cube.

int Isis::CubeIoHandler::getChunkCountInLineDimension ( ) const

protectedinherited

Returns: the total number of chunks in the line (Y) dimension. This is always enough to contain every line in the cube.

int Isis::CubeIoHandler::getChunkCountInSampleDimension ( ) const

protectedinherited

Returns: the total number of chunks in the sample (X) dimension. This is always enough to contain every sample in the cube.

int Isis::CubeIoHandler::getChunkIndex ( const RawCubeChunk & chunk ) const

protectedinherited

Given a chunk, what's its index in the file.

Chunks are ordered from left to right, then top to bottom, then front to back (BSQ). The first chunk is at the top left of band 1 and is index 0, for example. In other words, this is going from the value of m_rawData to the key.

Chunks which sit outside of the cube entirely must not be passed into this method; the results will be wrong.

Returns: The chunk's index into the file

References Isis::RawCubeChunk::getStartBand(), Isis::RawCubeChunk::getStartLine(), and Isis::RawCubeChunk::getStartSample().

QFile * Isis::CubeIoHandler::getDataFile ( )

protectedinherited

Returns: the QFile containing cube data. This is what should be read from and written to.; The data file for I/O

Referenced by Isis::CubeTileHandler::readRaw(), readRaw(), Isis::CubeTileHandler::writeRaw(), and writeRaw().

BigInt Isis::CubeIoHandler::getDataSize ( ) const

inherited

Returns: the number of bytes that the cube DNs will take up. This includes padding caused by the cube chunks not aligning with the cube dimensions.

BigInt Isis::CubeIoHandler::getDataStartByte ( ) const

protectedinherited

Returns: the byte offset to the beginning of the cube data.

int Isis::CubeIoHandler::getLineCountInChunk ( ) const

protectedinherited

Returns: the number of lines in each chunk of the cube.

Referenced by Isis::CubeTileHandler::updateLabels().

int Isis::CubeIoHandler::getSampleCountInChunk ( ) const

protectedinherited

Returns: the number of samples in each chunk of the cube.

Referenced by Isis::CubeTileHandler::updateLabels().

int Isis::CubeIoHandler::lineCount ( ) const

protectedinherited

Returns: the number of lines in the cube. This does not include lines created by the chunk overflowing the line dimension.

Referenced by CubeBsqHandler(), and Isis::CubeTileHandler::CubeTileHandler().

PixelType Isis::CubeIoHandler::pixelType ( ) const

protectedinherited

Returns: the physical cube DN format.

Referenced by CubeBsqHandler(), and Isis::CubeTileHandler::CubeTileHandler().

void Isis::CubeIoHandler::read ( Buffer & bufferToFill ) const

inherited

Read cube data from disk into the buffer.

This is not const because it caches the read cube chunks from the disk.

Parameters

bufferToFill The buffer to populate with cube data.

References Isis::Buffer::Band(), Isis::Buffer::BandDimension(), Isis::Buffer::Line(), Isis::Buffer::LineDimension(), Isis::Null, Isis::Buffer::Sample(), Isis::Buffer::SampleDimension(), and Isis::Buffer::size().

void Isis::CubeBsqHandler::readRaw ( RawCubeChunk & chunkToFill )

protectedvirtual

This needs to populate the chunkToFill with unswapped raw bytes from the disk.

See Also: CubeTileHandler::readRaw()

Parameters

chunkToFill The container that needs to be filled with cube data.

Implements Isis::CubeIoHandler.

References _FILEINFO_, Isis::RawCubeChunk::getByteCount(), Isis::CubeIoHandler::getDataFile(), Isis::IException::Io, and Isis::RawCubeChunk::setRawData().

int Isis::CubeIoHandler::sampleCount ( ) const

protectedinherited

Returns: the number of samples in the cube. This does not include samples created by the chunk overflowing the sample dimension.

Referenced by CubeBsqHandler(), and Isis::CubeTileHandler::CubeTileHandler().

void Isis::CubeIoHandler::setChunkSizes	(	int	numSamples,
		int	numLines,
		int	numBands
	)

protectedinherited

This should be called once from the child constructor.

This determines the chunk sizes used for the cube and often should remain constant for a particular cube (BSQ, for example, doesn't need it to be constant but Tile does). These being large can cause excessive use of disk space that stores no cube data. These being large can also drastically increase the amount of RAM consumed.

Parameters

numSamples	The chunk size in the sample dimension
numLines	The chunk size in the line dimension
numBands	The chunk size in the band dimension

References _FILEINFO_.

Referenced by CubeBsqHandler(), and Isis::CubeTileHandler::CubeTileHandler().

void Isis::CubeIoHandler::setVirtualBands ( const QList< int > * virtualBandList )

inherited

This changes the virtual band list.

Parameters

virtualBandList A list where the indices are the vbands and the values are the physical bands. The values are 1-based. This can be specified as NULL, in which case the vbands are the physical bands. The virtual band list is copied (the pointer provided isn't remembered).

void Isis::CubeBsqHandler::updateLabels ( Pvl & labels )

virtual

Children should probably implement this method.

This is called to allow the IO Handling algorithm to change the labels to include things like TileSamples/TileLines for example.

Parameters

labels The PVL cube label to be updated to reflect information that the child IO handlers need to properly re-read the cube.

Reimplemented from Isis::CubeIoHandler.

References Isis::PvlContainer::addKeyword(), Isis::PvlObject::findObject(), and Isis::PvlContainer::Replace.

void Isis::CubeIoHandler::write ( const Buffer & bufferToWrite )

inherited

Write buffer data into the cube data on disk.

This could do no IO if the cube chunks required are already in memory and our caching algorithms say to not free any of the cube chunks afterwards.

Parameters

bufferToWrite The buffer to get cube data from.

void Isis::CubeBsqHandler::writeRaw ( const RawCubeChunk & chunkToWrite )

protectedvirtual

This needs to write the chunkToWrite directly to disk with no modifications to the data itself.

See Also: CubeTileHandler::writeRaw()

Parameters

chunkToWrite The container that needs to be put on disk.

Implements Isis::CubeIoHandler.

References _FILEINFO_, Isis::RawCubeChunk::getByteCount(), Isis::CubeIoHandler::getDataFile(), Isis::RawCubeChunk::getRawData(), and Isis::IException::Io.

The documentation for this class was generated from the following files:

src/base/objs/Cube/CubeBsqHandler.h
src/base/objs/Cube/CubeBsqHandler.cpp

Public Member Functions

Protected Member Functions

Detailed Description

Constructor & Destructor Documentation

Member Function Documentation