Abstract base class for IO on a byte stream. More...

#include <ByteIO.h>

Inheritance diagram for casacore::ByteIO:

Public Types
enum	OpenOption { Old, Update, Append, New, NewNoReplace, Scratch, Delete }
	Define the possible ByteIO open options. More...

enum	SeekOption { Begin, Current, End }
	Define the possible seek options. More...

Public Member Functions
	ByteIO ()
	The constructor does nothing. More...

virtual	~ByteIO ()

virtual void	write (Int64 size, const void *buf)=0
	Write `size` bytes to the byte stream. More...

virtual void	pwrite (Int64 size, Int64 offset, const void *buf)
	Write `size` bytes to the byte stream at `offset`. More...

virtual Int64	read (Int64 size, void *buf, Bool throwException=True)=0
	Read `size` bytes from the byte stream. More...

virtual Int64	pread (Int64 size, Int64 offset, void *buf, Bool throwException=True)
	Like read but reads from offset of start of the file The file offset is not changed. More...

virtual void	reopenRW ()
	Reopen the underlying IO stream for read/write access. More...

Int64	seek (Int offset, ByteIO::SeekOption=ByteIO::Begin)
	This function sets the position on the given offset. More...

Int64	seek (Int64 offset, ByteIO::SeekOption=ByteIO::Begin)

virtual void	flush ()
	Flush the data to the file. More...

virtual void	fsync ()
	Fsync the file (i.e. More...

virtual void	resync ()
	Resync the file (i.e. More...

virtual String	fileName () const
	Get the file name of the file attached. More...

virtual Int64	length ()=0
	Get the length of the byte stream. More...

virtual Bool	isReadable () const =0
	Is the byte stream readable? More...

virtual Bool	isWritable () const =0
	Is the byte stream writable? More...

virtual Bool	isSeekable () const =0
	Is the byte stream seekable? More...

Protected Member Functions
	ByteIO (const ByteIO &byteIO)
	Make copy constructor and assignment protected, so a user cannot use them (but a derived class can). More...

ByteIO &	operator= (const ByteIO &byteIO)

virtual Int64	doSeek (Int64 offset, ByteIO::SeekOption)=0

Detailed Description

Abstract base class for IO on a byte stream.

Intended use:

Public interface

Review Status

Reviewed By:: Friso Olnon
Date Reviewed:: 1996/11/06
Test programs:: tByteIO

Synopsis

ByteIO is the abstract base class for all classes doing IO on byte streams. Examples of derived classes are RegularFileIO and MemoryIO.

ByteIO contains two enumerations, which define the possible open and seek options on byte streams. These enumerations are used throughout the IO framework.

Motivation

Make polymorphic operations on byte streams possible.

Definition at line 61 of file ByteIO.h.

Member Enumeration Documentation

enum casacore::ByteIO::OpenOption

Define the possible ByteIO open options.

Enumerator
Old
Update	read/write; file must exist.
Append	read/write; create file if not exist.
New	read/write; create file if not exist.
NewNoReplace	read/write; file may not exist yet.
Scratch	read/write; delete file at close.
Delete	read/write; file must exist; delete at close.

Definition at line 65 of file ByteIO.h.

enum casacore::ByteIO::SeekOption

Define the possible seek options.

Enumerator
Begin	Seek from beginning of file.
Current	Seek from current position.
End	Seek from the end of the file.

Definition at line 82 of file ByteIO.h.

Constructor & Destructor Documentation

casacore::ByteIO::ByteIO ( )

inline

The constructor does nothing.

Definition at line 172 of file ByteIO.h.

virtual casacore::ByteIO::~ByteIO ( )

virtual

casacore::ByteIO::ByteIO ( const ByteIO & byteIO )

inlineprotected

Make copy constructor and assignment protected, so a user cannot use them (but a derived class can).

Definition at line 175 of file ByteIO.h.

Member Function Documentation

virtual Int64 casacore::ByteIO::doSeek	(	Int64	offset,
		ByteIO::SeekOption
	)

protectedpure virtual

Implemented in casacore::MemoryIO, casacore::TapeIO, casacore::FiledesIO, casacore::FilebufIO, casacore::MFFileIO, casacore::MMapfdIO, and casacore::StreamIO.

Referenced by seek().

virtual String casacore::ByteIO::fileName ( ) const

virtual

Get the file name of the file attached.

The default implementation returns an empty string.

Reimplemented in casacore::TapeIO, casacore::FiledesIO, casacore::FilebufIO, casacore::MFFileIO, and casacore::RegularFileIO.

virtual void casacore::ByteIO::flush ( )

virtual

Flush the data to the file.

The default implementation does nothing.

Reimplemented in casacore::FilebufIO, casacore::MFFileIO, and casacore::MMapfdIO.

virtual void casacore::ByteIO::fsync ( )

virtual

Fsync the file (i.e.

force the data to be physically written). The default implementation does nothing.

Reimplemented in casacore::FiledesIO, and casacore::MFFileIO.

virtual Bool casacore::ByteIO::isReadable ( ) const

pure virtual

Is the byte stream readable?

Implemented in casacore::MemoryIO, casacore::TapeIO, casacore::FilebufIO, casacore::FiledesIO, casacore::MFFileIO, and casacore::StreamIO.

virtual Bool casacore::ByteIO::isSeekable ( ) const

pure virtual

Is the byte stream seekable?

Implemented in casacore::MemoryIO, casacore::TapeIO, casacore::FilebufIO, casacore::FiledesIO, casacore::MFFileIO, and casacore::StreamIO.

virtual Bool casacore::ByteIO::isWritable ( ) const

pure virtual

Is the byte stream writable?

Implemented in casacore::MemoryIO, casacore::TapeIO, casacore::FilebufIO, casacore::FiledesIO, casacore::MFFileIO, and casacore::StreamIO.

virtual Int64 casacore::ByteIO::length ( )

pure virtual

Get the length of the byte stream.

Implemented in casacore::MemoryIO, casacore::TapeIO, casacore::FilebufIO, casacore::FiledesIO, casacore::MFFileIO, and casacore::StreamIO.

ByteIO & casacore::ByteIO::operator= ( const ByteIO & byteIO )

inlineprotected

Definition at line 178 of file ByteIO.h.

virtual Int64 casacore::ByteIO::pread	(	Int64	size,
		Int64	offset,
		void *	buf,
		Bool	throwException = `True`
	)

virtual

Like read but reads from offset of start of the file The file offset is not changed.

Reimplemented in casacore::FiledesIO.

virtual void casacore::ByteIO::pwrite	(	Int64	size,
		Int64	offset,
		const void *	buf
	)

virtual

Write size bytes to the byte stream at offset.

The file offset is not changed

Reimplemented in casacore::FiledesIO.

virtual Int64 casacore::ByteIO::read	(	Int64	size,
		void *	buf,
		Bool	throwException = `True`
	)

pure virtual

Read size bytes from the byte stream.

Returns the number of bytes actually read, or a negative number if an error occurred. Will also throw an Exception (AipsError) if the requested number of bytes could not be read unless throwException is set to False.

Implemented in casacore::MemoryIO, casacore::TapeIO, casacore::FilebufIO, casacore::FiledesIO, casacore::MMapfdIO, casacore::MFFileIO, and casacore::StreamIO.

virtual void casacore::ByteIO::reopenRW ( )

virtual

Reopen the underlying IO stream for read/write access.

Nothing will be done if the stream is writable already. Otherwise it will be reopened and an exception will be thrown if it is not possible to reopen it for read/write access. The default implementation in this base class throws a "not possible" exception if a reopen has to be done.

Reimplemented in casacore::MFFileIO, and casacore::RegularFileIO.

Referenced by casacore::StManArrayFile::reopenRW().

virtual void casacore::ByteIO::resync ( )

virtual

Resync the file (i.e.

empty the current buffer). The default implementation does nothing.

Reimplemented in casacore::FilebufIO.