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/*
* $Id$
*
* ***** BEGIN LGPL LICENSE BLOCK *****
*
* Copyright 2009 Jörg Hermann Müller
*
* This file is part of AudaSpace.
*
* AudaSpace is free software: you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* AudaSpace 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 Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with AudaSpace. If not, see <http://www.gnu.org/licenses/>.
*
* ***** END LGPL LICENSE BLOCK *****
*/
#ifndef AUD_IREADER
#define AUD_IREADER
#include "AUD_Space.h"
/**
* This class represents a sound source as stream or as buffer which can be read
* for example by another reader, a device or whatever.
*/
class AUD_IReader
{
public:
/**
* Destroys the reader.
*/
virtual ~AUD_IReader(){}
/**
* Tells whether the source provides seeking functionality or not.
* \warning This doesn't mean that the seeking always has to succeed.
* \return Always returns true for readers of the buffer type.
* \see getType
*/
virtual bool isSeekable()=0;
/**
* Seeks to a specific position in the source.
* This function must work for buffer type readers.
* \param position The position to seek for measured in samples. To get
* from a given time to the samples you simply have to multiply the
* time value in seconds with the sample rate of the reader.
* \warning This may work or not, depending on the actual reader.
* \see getType
*/
virtual void seek(int position)=0;
/**
* Returns an aproximated length of the source in samples.
* For readers of the type buffer this has to return a correct value!
* \return The length as sample count. May be negative if unknown.
* \see getType
*/
virtual int getLength()=0;
/**
* Returns the position of the source as a sample count value.
* \return The current position in the source. A negative value indicates
* that the position is unknown.
* \warning The value returned doesn't always have to be correct for readers
* of the stream type, especially after seeking, it must though for
* the buffer ones.
* \see getType
*/
virtual int getPosition()=0;
/**
* Returns the specification of the reader.
* \return The AUD_Specs structure.
*/
virtual AUD_Specs getSpecs()=0;
/**
* Returns the type of the reader. There are special conditions for the
* readers of the buffer type. Those have to return correct position and
* length values as well as they must be seekable.
* \return AUD_TYPE_BUFFER or AUD_TYPE_STREAM.
*/
virtual AUD_ReaderType getType()=0;
/**
* Sends a message to this reader and if it has subreaders it broadcasts
* the message to them.
* \param message The message.
* \return Whether the message has been read by the reader or one of his
* subreaders.
*/
virtual bool notify(AUD_Message &message)=0;
/**
* Request to read the next length samples out of the source.
* The buffer for reading has to stay valid until the next call of this
* method or until the reader is deleted.
* \param[in,out] length The count of samples that should be read. Shall
* contain the real count of samples after reading, in case
* there were only fewer samples available.
* A smaller value also indicates the end of the reader.
* \param[out] buffer The pointer to the buffer with the samples.
*/
virtual void read(int & length, sample_t* & buffer)=0;
};
#endif //AUD_IREADER
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