The Stream interface can be used to implement a data source or sink. More...

#include <stream.h>

Inheritance diagram for Stream:

Public Member Functions
	~Stream ()
	Empty destructor.

virtual bool_t	canRead () const =0
	Checks whether the stream supports reading.

virtual bool_t	canSeek () const =0
	Checks whether the stream supports seeking.

virtual bool_t	canWrite () const =0
	Checks whether the stream supports writing.

virtual void	close ()=0
	Closes the stream.

virtual bool_t	isOpen () const =0
	Checks whether the stream is open.

virtual bool_t	open ()=0
	Opens the stream.

virtual int64_t	position () const =0
	Returns the current position in the stream.

virtual bool_t	read (void buffer, int32_t bufferSize, int32_t totalRead)=0
	Reads data from the stream.

int32_t	release () const
	The default implementation keeps a constant reference count of 1.

int32_t	retain () const
	The default implementation keeps a constant reference count of 1.

int32_t	retainCount () const
	The default implementation keeps a constant reference count of 1.

virtual bool_t	seek (int64_t position)=0
	Seeks to the specified position in the stream.

virtual int64_t	size () const =0
	Returns the current size of the stream.

virtual bool_t	write (const void *buffer, int32_t dataSize)=0
	Writes data to the stream.

virtual int32_t	release () const =0
	Releases the instance.

virtual int32_t	retain () const =0
	Retains the instance.

virtual int32_t	retainCount () const =0
	Returns the current reference count.

Detailed Description

The Stream interface can be used to implement a data source or sink.

It can be used as an alternative to files when it is not convenient or possible to use files.

The default implementation of primo::Reference keeps a constant reference count of 1. This can be used when the client code is the sole owner of the implemented stream and does not need to manage it through the primo::Reference interface.

Member Function Documentation

◆ canRead()

virtual bool_t canRead ( ) const

pure virtual

Checks whether the stream supports reading.

Returns: TRUE It is possible to read form the stream. FALSE It is not possible to read from the stream and the read method always returns FALSE.

◆ canSeek()

virtual bool_t canSeek ( ) const

pure virtual

Checks whether the stream supports seeking.

Returns: TRUE It is possible to seek in the stream. FALSE It is not possible to seek in the stream and the seek method always returns FALSE.

◆ canWrite()

virtual bool_t canWrite ( ) const

pure virtual

Checks whether the stream supports writing.

Returns: TRUE It is possible to write to the stream. FALSE It is not possible to write to the stream and the write method always returns FALSE.

◆ isOpen()

virtual bool_t isOpen ( ) const

pure virtual

Checks whether the stream is open.

Returns: TRUE The stream is open, FALSE the stream is closed.

◆ open()

virtual bool_t open ( )

pure virtual

Opens the stream.

Returns: TRUE The stream is opened successfully. FALSE An error occurred.

◆ position()

virtual int64_t position ( ) const

pure virtual

Returns the current position in the stream.

Returns: Absolute position in stream or -1 if the stream cannot be seeked. The beginning of a seekable the stream is at position 0.

See also: canSeek

◆ read()

virtual bool_t read	(	void *	buffer,
		int32_t	bufferSize,
		int32_t *	totalRead
	)

pure virtual

Reads data from the stream.

Parameters

buffer	[in] A pointer to the buffer where the data shall be stored.
bufferSize	[in] Buffer size in bytes. Specifies how many bytes shall be read from the stream.
totalRead	[out] A pointer to a variable that stores the actual number of bytes read from the stream. When the number of bytes returned (totalRead) is 0 then this is considered to be the end of the stream (EOS). Reading at the end of the stream succeeds but 0 bytes are returned. The number of bytes returned (totalRead) may be less than the requested bytes (bufferSize) even before the end of the stream is reached.

Remarks: This function should block if no data is currently available in stream but more is expected to come: from network, growing file, expandable buffer, etc. The parameter totalRead should be set to 0 only when no more data is available in stream and no more data is expected to come.

Returns: TRUE The operation is successful. FALSE Could not read from the stream.

See also: canRead

◆ release()

int32_t release ( ) const

virtual

The default implementation keeps a constant reference count of 1.

Returns: 1

Implements Reference.

◆ retain()

int32_t retain ( ) const

virtual

The default implementation keeps a constant reference count of 1.

Returns: 1

Implements Reference.

◆ retainCount()

int32_t retainCount ( ) const

virtual

The default implementation keeps a constant reference count of 1.

Returns: 1

Implements Reference.

◆ seek()

virtual bool_t seek ( int64_t position )

pure virtual

Seeks to the specified position in the stream.

Parameters

position [in] Specifies the absolute position from the beginning of the stream (which is at position 0).

Returns: TRUE if successful. FALSE if there's an error.

See also: canSeek

◆ size()

virtual int64_t size ( ) const

pure virtual

Returns the current size of the stream.

Returns: Stream size in bytes. If the size is unknown -1 is returned.

Remarks: The stream size may increase if more data is appended to the stream. The stream size should never decrease.

◆ write()

virtual bool_t write	(	const void *	buffer,
		int32_t	dataSize
	)

pure virtual

Writes data to the stream.

Parameters

buffer	[in] A pointer to the data that shall be written to the stream.
dataSize	[in] Specifies how many bytes to write.

Returns: TRUE the data has been written to the stream. FALSE an error occurred while writing to the stream.

See also: canWrite

Public Member Functions

Detailed Description

Member Function Documentation

◆ canRead()

◆ canSeek()

◆ canWrite()

◆ isOpen()

◆ open()

◆ position()

◆ read()

◆ release()

◆ retain()

◆ retainCount()

◆ seek()

◆ size()

◆ write()