BaseSinkSource.h

Classes

BaseSinkSource -- Shared base class for ByteSink and ByteSource. (full description)

class BaseSinkSource

Interface

Public Members

TypeIO& typeIO()

const TypeIO& typeIO() const

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

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

Bool isReadable() const

Bool isWritable() const

Bool isSeekable() const

Bool isNull() const

Protected Members

BaseSinkSource()

BaseSinkSource (TypeIO* typeIO, Bool takeOver=False)

BaseSinkSource (const BaseSinkSource& BaseSinkSource)

BaseSinkSource& operator= (const BaseSinkSource& BaseSinkSource)

virtual ~BaseSinkSource()

Description

Prerequisite

TypeIO class and derived classes

Review Status

Reviewed By:

Friso Olnon

Date Reviewed:

1996/11/06

Programs:

Tests:

tByteSink

Synopsis

This class provides the common functionality for the classes ByteSink and ByteSource.

The object is constructed using a typed byte stream. This stream is an instance of a class derived from class TypeIO. This makes it possible to store the data in any format (e.g. CanonicalIO or RawIO). Class CanonicalIO makes it possible to store the data in a canonical (machine-independent) format, so it can be read on any machine and operating system. The canonical format is big-endian IEEE, where a (unsigned) long is stored as 8 bytes. This means that on common 32-bit big-endian machines like SUN and HP only longs have to be converted and that CanonicalIO is as fast as RawIO. Class RawIO stores the data in native format, so the IO-process is faster on especially little-endian machines (PC, DEC-alpha). Note that RawIO can also be used to read bytes and interprete or convert them thereafter (e.g. using the conversion functions in the Conversion Conversion framework.

In its turn TypeIO uses an instance of a class derived from class ByteIO. This makes it possible to use any output stream (e.g. file, memory).

Motivation

The design of the ByteSink and ByteSource classes resembles the design of the iostream classes in the standard library. A shared base class is needed to allow multiple inheritance needed for class ByteSinkSource.

Member Description

TypeIO& typeIO()
const TypeIO& typeIO() const

This functions returns a reference to itsTypeIO.

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

This function sets the position on the given offset. The seek option defines from which position the seek is done.

Bool isReadable() const

Is the SinkSource readable?

Bool isWritable() const

Is the SinkSource writable?

Bool isSeekable() const

Is the SinkSource seekable?

Bool isNull() const

Is the BaseSinkSource unusable?

BaseSinkSource()

BaseSinkSource (TypeIO* typeIO, Bool takeOver=False)

Construct using the given TypeIO. If takeOver is true the this class will delete the supplied pointer. Otherwise the caller is responsible for this.