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/*------------------------------------------------------------------------------
Copyright (c) 2000-2007 Tyrell Corporation. All rights reserved.
Tyrell DarkIce
File : BufferedSink.h
Version : $Revision: 553 $
Author : $Author: rafael@riseup.net $
Location : $HeadURL: https://darkice.googlecode.com/svn/darkice/tags/darkice-1_2/src/BufferedSink.h $
Copyright notice:
This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License
as published by the Free Software Foundation; either version 3
of the License, or (at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
------------------------------------------------------------------------------*/
#ifndef BUFFERED_SINK_H
#define BUFFERED_SINK_H
#ifndef __cplusplus
#error This is a C++ include file
#endif
/* ============================================================ include files */
#include "Ref.h"
#include "Reporter.h"
#include "Sink.h"
/* ================================================================ constants */
/* =================================================================== macros */
/* =============================================================== data types */
/**
* A Sink First-In First-Out buffer.
* This buffer can always be written to, it overwrites any
* data contained if needed.
* The class is not thread-safe.
*
* @author $Author: rafael@riseup.net $
* @version $Revision: 553 $
*/
class BufferedSink : public Sink, public virtual Reporter
{
private:
/**
* The buffer.
*/
unsigned char * buffer;
/**
* The end of the buffer.
*/
unsigned char * bufferEnd;
/**
* The size of the buffer.
*/
unsigned int bufferSize;
/**
* The highest usage of the buffer.
*/
unsigned int peak;
/**
* All data written to this BufferedSink is handled by chuncks
* of this size.
*/
unsigned int chunkSize;
/**
* Number of bytes the underlying stream is misaligned with
* chunkSize. (It needs this many bytes more to be aligned.)
*/
unsigned int misalignment;
/**
* Start of free territory in buffer.
*/
unsigned char * inp;
/**
* Start of sensible data in buffer.
*/
unsigned char * outp;
/**
* The underlying Sink.
*/
Ref<Sink> sink;
/**
* Initialize the object.
*
* @param sink the Sink to attach this BufferedSink to.
* @param size the size of the internal buffer to use.
* @param chunkSize size of chunks to handle data in.
* @exception Exception
*/
void
init ( Sink * sink,
unsigned int size,
unsigned int chunkSize ) throw ( Exception );
/**
* De-initialize the object.
*
* @exception Exception
*/
void
strip ( void ) throw ( Exception );
/**
* Slide a pointer in the internal buffer by offset. If the pointer
* would reach beyond the end of the buffer, it goes wraps around.
*
* @param p the pointer to slide.
* @param offset the amount to slide with.
* @return pointer p + offset, wrapped around if needed.
*/
inline unsigned char *
slidePointer (
unsigned char * p,
unsigned int offset ) throw ()
{
p += offset;
while ( p >= bufferEnd ) {
p -= bufferSize;
}
return p;
}
/**
* Update the peak buffer usage indicator.
*
* @see #peak
*/
inline void
updatePeak ( void ) throw ()
{
unsigned int u;
u = outp <= inp ? inp - outp : (bufferEnd - outp) + (inp - buffer);
if ( peak < u ) {
peak = u;
reportEvent( 4, "BufferedSink, new peak:", peak);
reportEvent( 4, "BufferedSink, remaining:", bufferSize - peak);
}
}
/**
* If the underlying Sink is misaligned on chunkSize, write as
* many 0s as needed to get it aligned.
*
* @see #misalignment
* @see #chunkSize
*/
inline bool
align ( void ) throw ( Exception )
{
char b[] = { 0 };
while ( misalignment ) {
if ( sink->canWrite( 0, 0) ) {
unsigned int ret;
if ( !(ret = sink->write( b, 1)) ) {
return false;
}
--misalignment;
} else {
return false;
}
}
return true;
}
protected:
/**
* Default constructor. Always throws an Exception.
*
* @exception Exception
*/
inline
BufferedSink ( void ) throw ( Exception )
{
throw Exception( __FILE__, __LINE__);
}
/**
* Get the size of the buffer.
*
* @return the size of the buffer.
*/
inline unsigned int
getSize ( void ) const throw ()
{
return bufferSize;
}
/**
* Store data in the internal buffer. If there is not enough space,
* discard all in the buffer and the beginning of the supplied
* buffer if needed.
*
* @param buffer the data to store.
* @param bufferSize the amount of data to store in bytes.
* @return number of bytes really stored.
*/
unsigned int
store ( const void * buffer,
unsigned int bufferSize ) throw ( Exception );
public:
/**
* Constructor by an underlying Sink, buffer size and chunk size.
*
* @param sink the Sink to attach this BufferSink to.
* @param size the size of the buffer to use for buffering.
* @param chunkSize hanlde all data in write() as chunks of
* chunkSize
* @exception Exception
*/
inline
BufferedSink ( Sink * sink,
unsigned int size,
unsigned int chunkSize = 1 ) throw ( Exception )
{
init( sink, size, chunkSize);
}
/**
* Copy constructor.
*
* @param buffer the object to copy.
* @exception Exception
*/
BufferedSink ( const BufferedSink & buffer ) throw ( Exception );
/**
* Destructor.
*
* @exception Exception
*/
inline virtual
~BufferedSink ( void ) throw ( Exception )
{
strip();
}
/**
* Assignment operator.
*
* @param bs the object to assign to this one.
* @return a reference to this object.
* @exception Exception
*/
virtual BufferedSink &
operator= ( const BufferedSink & bs ) throw ( Exception );
/**
* Get the peak usage of the internal buffer.
*
* @return the peak usage of the internal buffer.
*/
inline unsigned int
getPeak ( void ) const throw ()
{
return peak;
}
/**
* Open the BufferedSink. Opens the underlying Sink.
*
* @return true if opening was successful, false otherwise.
* @exception Exception
*/
inline virtual bool
open ( void ) throw ( Exception )
{
return sink->open();
}
/**
* Check if a BufferedSink is open.
*
* @return true if the BufferedSink is open, false otherwise.
*/
inline virtual bool
isOpen ( void ) const throw ()
{
return sink->isOpen();
}
/**
* Check if the BufferedSink is ready to accept data.
* Always returns true immediately.
*
* @param sec the maximum seconds to block.
* @param usec micro seconds to block after the full seconds.
* @return true
* @exception Exception
*/
inline virtual bool
canWrite ( unsigned int sec,
unsigned int usec ) throw ( Exception )
{
return true;
}
/**
* Write data to the BufferedSink.
* Always reads the maximum number of chunkSize chunks buf
* holds. If the data can not be written to the underlying
* stream, it is buffered. If the buffer overflows, the oldest
* data is discarded.
*
* @param buf the data to write.
* @param len number of bytes to write from buf.
* @return the number of bytes written (may be less than len).
* @exception Exception
*/
virtual unsigned int
write ( const void * buf,
unsigned int len ) throw ( Exception );
/**
* Flush all data that was written to the BufferedSink to the
* underlying Sink.
*
* @exception Exception
*/
inline virtual void
flush ( void ) throw ( Exception )
{
unsigned char b[1];
write( b, 0);
}
/**
* Cut what the sink has been doing so far, and start anew.
* This usually means separating the data sent to the sink up
* until now, and start saving a new chunk of data.
*/
inline virtual void
cut ( void ) throw ()
{
flush();
sink->cut();
}
/**
* Close the BufferedSink. Closes the underlying Sink.
*
* @exception Exception
*/
virtual void
close ( void ) throw ( Exception );
};
/* ================================================= external data structures */
/* ====================================================== function prototypes */
#endif /* BUFFERED_SINK_H */
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