Aufgabe 6: Synchronisation

Public Member Functions | Protected Member Functions | Protected Attributes | List of all members
Stringbuffer Class Referenceabstract

The class Stringbuffer composes single characters into a longer text that can be processed on block. More...

#include <object/stringbuffer.h>

+ Inheritance diagram for Stringbuffer:

Public Member Functions

virtual ~Stringbuffer ()
 Destructor (nothing to do here)
 

Protected Member Functions

 Stringbuffer ()
 Constructor; Marks the buffer as empty.
 
void put (char c)
 Inserts a character into the buffer. More...
 
virtual void flush ()=0
 Flush the buffer contents. More...
 

Protected Attributes

char buffer [80]
 buffer containing characters that will be printed upon flush()
 
long unsigned pos
 current position in the buffer
 

Detailed Description

The class Stringbuffer composes single characters into a longer text that can be processed on block.

To make Stringbuffer as versatile as possible, the class does make assumptions about neither the underlying hardware, nor the meaning of "processing". When flush() is called (i.e., either on explicit request or once the buffer is full). To be hardware independent, flush() is to be implemented by the derived classes.

Hints for Implementation
Use a buffer of fixed size for caching characters, which should be accessible by derived classes. Keep in mind that the derived implementation of flush() will need to know about numbers of characters in the buffer.
Notes
Reason for the existence of this class is that generating longer texts is often implemented by assembly of small fragments (such as single characters or numbers). However, writing such small fragments directly to (for example) screen is quite inefficient (e.g., due to the use of IO ports, syscalls, or locks) and can be improved drastically by delaying the output step until the assembly is finished (or the buffer runs full).

Member Function Documentation

void Stringbuffer::put ( char  c)
protected

Inserts a character into the buffer.

Once the buffer is full, a call to flush() will be issued and thereby clearing the buffer.

Parameters
cChar to be added
virtual void Stringbuffer::flush ( )
protectedpure virtual

Flush the buffer contents.

This method is to be defined in derived classes, as only those know how to print characters. flush() is required to reset the position pos.

Implemented in SerialStream, TextStream, ConsoleOut, FileOut, and OutputStream.

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