QtlFileSlices Class Reference

A read-only file device with sequential access on a list of data slices. More...

Inheritance diagram for QtlFileSlices:

Public Member Functions
	QtlFileSlices (const QString &fileName, const QtlRangeList &slices=QtlRangeList(), QObject *parent=0)
	Constructor. More...
virtual bool	atEnd () const Q_DECL_OVERRIDE
	Returns true if the current read position is at the end of the device. More...
virtual void	close () Q_DECL_OVERRIDE
	Close the device. More...
QString	fileName () const
	Get the file name. More...
virtual bool	isSequential () const Q_DECL_OVERRIDE
	Returns true if this device is sequential; otherwise returns false. More...
virtual bool	open (OpenMode mode=ReadOnly) Q_DECL_OVERRIDE
	Open the device. More...
virtual qint64	pos () const Q_DECL_OVERRIDE
	Get the position that data is read from. More...
virtual qint64	size () const Q_DECL_OVERRIDE
	Get the size of the device, meaning the number of bytes to read. More...

Protected Member Functions
virtual qint64	readData (char *data, qint64 maxSize) Q_DECL_OVERRIDE
	Reads up to maxSize bytes from the device into data. More...
virtual qint64	writeData (const char *data, qint64 maxSize) Q_DECL_OVERRIDE
	Writes up to maxSize bytes from data to the device. More...

Private Member Functions
	QtlFileSlices () Q_DECL_EQ_DELETE

Private Attributes
QtlRangeList::ConstIterator	_currentSlice
	Current pointer in _slices. More...
QFile	_file
	Actual device to read. More...
int	_nextByte
	Next byte in _currentSlice, -1 means at beginning. More...
qint64	_readSize
	Number of bytes already read in the file. More...
qint64	_size
	Number of bytes to read in the file. More...
QtlRangeList	_slices
	Slices of file to read. More...

Detailed Description

A read-only file device with sequential access on a list of data slices.

When reading the file, only specific portions of the physical files are read.

Constructor & Destructor Documentation

QtlFileSlices() [1/2]

QtlFileSlices::QtlFileSlices ( const QString &  fileName, const QtlRangeList &  slices = QtlRangeList(), QObject *  parent = 0  )

explicit

Constructor.

Parameters

[in]	fileName	Name of the file.
[in]	slices	Slices of data to read in the files. If empty, the whole file is read.
[in]	parent	Optional parent object.

QtlFileSlices() [2/2]

QtlFileSlices::QtlFileSlices ( )

private

Member Function Documentation

fileName()

QString QtlFileSlices::fileName ( ) const

inline

Get the file name.

Returns

The file name.

open()

bool QtlFileSlices::open ( OpenMode  mode = ReadOnly )

virtual

Open the device.

Reimplemented from QIODevice.

Parameters

[in]

mode

Open mode. The only allowed mode is ReadOnly, with optional flag Text. All other modes are forbidden.

Returns

True on success, false on error.

close()

void QtlFileSlices::close ( )

virtual

Close the device.

Reimplemented from QIODevice.

size()

virtual qint64 QtlFileSlices::size ( ) const

inlinevirtual

Get the size of the device, meaning the number of bytes to read.

Reimplemented from QIODevice.

Returns

The number of bytes to read, which is the sum of all slices to read. This is different from the size of the underlying file. If some slices overlap, the same data are counted several times.

pos()

virtual qint64 QtlFileSlices::pos ( ) const

inlinevirtual

Get the position that data is read from.

Reimplemented from QIODevice.

Returns

The current position in the slices, which is also the number of bytes already read.

atEnd()

virtual bool QtlFileSlices::atEnd ( ) const

inlinevirtual

Returns true if the current read position is at the end of the device.

Reimplemented from QIODevice.

Returns

True if there is no more data to read, false otherwise.

isSequential()

virtual bool QtlFileSlices::isSequential ( ) const

inlinevirtual

Returns true if this device is sequential; otherwise returns false.

Reimplemented from QIODevice.

Returns

Always true.

readData()

qint64 QtlFileSlices::readData ( char *  data, qint64  maxSize  )

protectedvirtual

Reads up to maxSize bytes from the device into data.

Implemented from QIODevice requirement.

Parameters

[out]	data	Buffer for returned data.
[in]	maxSize	Maximum number of bytes to read.

Returns

Number of bytes read or -1 if an error occurred.

writeData()

virtual qint64 QtlFileSlices::writeData ( const char *  data, qint64  maxSize  )

inlineprotectedvirtual

Writes up to maxSize bytes from data to the device.

Implemented from QIODevice requirement.

Parameters

[in]	data	Buffer for data to write.
[in]	maxSize	Maximum number of bytes to write.

Returns

Always -1 (error) since the file is read-only.

Member Data Documentation

_slices

QtlRangeList QtlFileSlices::_slices

private

Slices of file to read.

_size

qint64 QtlFileSlices::_size

private

Number of bytes to read in the file.

_readSize

qint64 QtlFileSlices::_readSize

private

Number of bytes already read in the file.

_file

QFile QtlFileSlices::_file

private

Actual device to read.

_nextByte

int QtlFileSlices::_nextByte

private

Next byte in _currentSlice, -1 means at beginning.

_currentSlice

QtlRangeList::ConstIterator QtlFileSlices::_currentSlice

private

Current pointer in _slices.

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

• QtlFileSlices.h
• QtlFileSlices.cpp