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

#include <ByteIO.h>

Inheritance diagram for casa::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.
virtual	~ByteIO ()
virtual void	write (uInt size, const void *buf)=0
	Write `size` bytes to the byte stream.
virtual Int	read (uInt size, void *buf, Bool throwException=True)=0
	Read `size` bytes from the byte stream.
virtual void	reopenRW ()
	Reopen the underlying IO stream for read/write access.
Int64	seek (Int offset, ByteIO::SeekOption=ByteIO::Begin)
	This function sets the position on the given offset.
Int64	seek (Int64 offset, ByteIO::SeekOption=ByteIO::Begin)
virtual Int64	length ()=0
	Get the length of the byte stream.
virtual Bool	isReadable () const =0
	Is the byte stream readable?
virtual Bool	isWritable () const =0
	Is the byte stream writable?
virtual Bool	isSeekable () const =0
	Is the byte stream seekable?
Protected Member Functions
	ByteIO (const ByteIO &byteIO)
	Make copy constructor and assignment protected, so a user cannot use them (but a derived class can).
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

 <h3>Review Status</h3><dl><dt>Reviewed By:<dd>Friso Olnon<dt>Date Reviewed:<dd>1996/11/06<dt>Test programs:<dd>tByteIO</dl> 

<h3>Synopsis</h3> 
ByteIO is the abstract base class for all classes doing IO on
byte streams. Examples of derived classes are
  \link casa::RegularFileIO RegularFileIO \endlink  and
  \link casa::MemoryIO MemoryIO \endlink .
<p>
ByteIO contains two enumerations, which define the possible
open and seek options on byte streams. These enumerations
are used throughout the IO framework.

<h3>Motivation</h3> 
Make polymorphic operations on byte streams possible.

Definition at line 60 of file ByteIO.h.

Member Enumeration Documentation

enum casa::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 64 of file ByteIO.h.

enum casa::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 81 of file ByteIO.h.

Constructor & Destructor Documentation

casa::ByteIO::ByteIO ( ) [inline]

The constructor does nothing.

Definition at line 147 of file ByteIO.h.

virtual casa::ByteIO::~ByteIO ( ) [virtual]

casa::ByteIO::ByteIO ( const ByteIO & byteIO ) [inline, protected]

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

Definition at line 150 of file ByteIO.h.

Member Function Documentation

virtual Int64 casa::ByteIO::doSeek	(	Int64	offset,
		ByteIO::SeekOption
	)		`[protected, pure virtual]`

Implemented in casa::MemoryIO, casa::TapeIO, casa::FilebufIO, casa::LargeFilebufIO, casa::LargeFiledesIO, casa::FiledesIO, casa::MMapfdIO, and casa::StreamIO.

Referenced by seek().

virtual Bool casa::ByteIO::isReadable ( ) const [pure virtual]

Is the byte stream readable?

Implemented in casa::MemoryIO, casa::TapeIO, casa::FilebufIO, casa::LargeFilebufIO, casa::LargeFiledesIO, casa::FiledesIO, and casa::StreamIO.

virtual Bool casa::ByteIO::isSeekable ( ) const [pure virtual]

Is the byte stream seekable?

Implemented in casa::MemoryIO, casa::TapeIO, casa::FilebufIO, casa::LargeFilebufIO, casa::LargeFiledesIO, casa::FiledesIO, and casa::StreamIO.

virtual Bool casa::ByteIO::isWritable ( ) const [pure virtual]

Is the byte stream writable?

Implemented in casa::MemoryIO, casa::TapeIO, casa::FilebufIO, casa::LargeFilebufIO, casa::LargeFiledesIO, casa::FiledesIO, and casa::StreamIO.

virtual Int64 casa::ByteIO::length ( ) [pure virtual]

Get the length of the byte stream.

Implemented in casa::MemoryIO, casa::TapeIO, casa::FilebufIO, casa::LargeFilebufIO, casa::LargeFiledesIO, casa::FiledesIO, and casa::StreamIO.

ByteIO & casa::ByteIO::operator= ( const ByteIO & byteIO ) [inline, protected]

Definition at line 153 of file ByteIO.h.

virtual Int casa::ByteIO::read	(	uInt	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 occured. Will also throw an Exception (AipsError) if the requested number of bytes could not be read unless throwException is set to False.

Implemented in casa::MemoryIO, casa::TapeIO, casa::FilebufIO, casa::LargeFilebufIO, casa::LargeFiledesIO, casa::FiledesIO, casa::MMapfdIO, and casa::StreamIO.

virtual void casa::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 casa::LargeRegularFileIO, and casa::RegularFileIO.

Int64 casa::ByteIO::seek	(	Int	offset,
		ByteIO::SeekOption	option = `ByteIO::Begin`
	)		`[inline]`

This function sets the position on the given offset.

The seek option defines from which file position the seek is done. -1 is returned if not seekable.

Definition at line 162 of file ByteIO.h.

References doSeek().

Int64 casa::ByteIO::seek	(	Int64	offset,
		ByteIO::SeekOption	option = `ByteIO::Begin`
	)		`[inline]`

Definition at line 158 of file ByteIO.h.

References doSeek().

virtual void casa::ByteIO::write	(	uInt	size,
		const void *	buf
	)		`[pure virtual]`

Write size bytes to the byte stream.

Implemented in casa::MemoryIO, casa::TapeIO, casa::FilebufIO, casa::LargeFilebufIO, casa::LargeFiledesIO, casa::FiledesIO, casa::MMapfdIO, and casa::StreamIO.

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

casacore/casa/IO/ByteIO.h

Public Types

Public Member Functions

Protected Member Functions

Detailed Description

Intended use:

Member Enumeration Documentation

Constructor & Destructor Documentation

Member Function Documentation