soundtouch/include/FIFOSamplePipe.h

////////////////////////////////////////////////////////////////////////////////
///
/// 'FIFOSamplePipe' : An abstract base class for classes that manipulate sound
/// samples by operating like a first-in-first-out pipe: New samples are fed
/// into one end of the pipe with the 'putSamples' function, and the processed
/// samples are received from the other end with the 'receiveSamples' function.
///
/// 'FIFOProcessor' : A base class for classes the do signal processing with 
/// the samples while operating like a first-in-first-out pipe. When samples
/// are input with the 'putSamples' function, the class processes them
/// and moves the processed samples to the given 'output' pipe object, which
/// may be either another processing stage, or a fifo sample buffer object.
///
/// Author        : Copyright (c) Olli Parviainen
/// Author e-mail : oparviai 'at' iki.fi
/// SoundTouch WWW: http://www.surina.net/soundtouch
///
////////////////////////////////////////////////////////////////////////////////
//
// Last changed  : $Date$
// File revision : $Revision: 4 $
//
// $Id$
//
////////////////////////////////////////////////////////////////////////////////
//
// License :
//
//  SoundTouch audio processing library
//  Copyright (c) Olli Parviainen
//
//  This library 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 2.1 of the License, or (at your option) any later version.
//
//  This library 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 this library; if not, write to the Free Software
//  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
//
////////////////////////////////////////////////////////////////////////////////

#ifndef FIFOSamplePipe_H
#define FIFOSamplePipe_H

#include <assert.h>
#include <stdlib.h>
#include "STTypes.h"

namespace soundtouch
{

/// Abstract base class for FIFO (first-in-first-out) sample processing classes.
class FIFOSamplePipe
{
public:
    // virtual default destructor
    virtual ~FIFOSamplePipe() {}


    /// Returns a pointer to the beginning of the output samples. 
    /// This function is provided for accessing the output samples directly. 
    /// Please be careful for not to corrupt the book-keeping!
    ///
    /// When using this function to output samples, also remember to 'remove' the
    /// output samples from the buffer by calling the 
    /// 'receiveSamples(numSamples)' function
    virtual SAMPLETYPE *ptrBegin() = 0;

    /// Adds 'numSamples' pcs of samples from the 'samples' memory position to
    /// the sample buffer.
    virtual void putSamples(const SAMPLETYPE *samples,  ///< Pointer to samples.
                            uint numSamples             ///< Number of samples to insert.
                            ) = 0;


    // Moves samples from the 'other' pipe instance to this instance.
    void moveSamples(FIFOSamplePipe &other  ///< Other pipe instance where from the receive the data.
         )
    {
        int oNumSamples = other.numSamples();

        putSamples(other.ptrBegin(), oNumSamples);
        other.receiveSamples(oNumSamples);
    };

    /// Output samples from beginning of the sample buffer. Copies requested samples to 
    /// output buffer and removes them from the sample buffer. If there are less than 
    /// 'numsample' samples in the buffer, returns all that available.
    ///
    /// \return Number of samples returned.
    virtual uint receiveSamples(SAMPLETYPE *output, ///< Buffer where to copy output samples.
                                uint maxSamples                 ///< How many samples to receive at max.
                                ) = 0;

    /// Adjusts book-keeping so that given number of samples are removed from beginning of the 
    /// sample buffer without copying them anywhere. 
    ///
    /// Used to reduce the number of samples in the buffer when accessing the sample buffer directly
    /// with 'ptrBegin' function.
    virtual uint receiveSamples(uint maxSamples   ///< Remove this many samples from the beginning of pipe.
                                ) = 0;

    /// Returns number of samples currently available.
    virtual uint numSamples() const = 0;

    // Returns nonzero if there aren't any samples available for outputting.
    virtual int isEmpty() const = 0;

    /// Clears all the samples.
    virtual void clear() = 0;

    /// allow trimming (downwards) amount of samples in pipeline.
    /// Returns adjusted amount of samples
    virtual uint adjustAmountOfSamples(uint numSamples) = 0;

};



/// Base-class for sound processing routines working in FIFO principle. With this base 
/// class it's easy to implement sound processing stages that can be chained together,
/// so that samples that are fed into beginning of the pipe automatically go through 
/// all the processing stages.
///
/// When samples are input to this class, they're first processed and then put to 
/// the FIFO pipe that's defined as output of this class. This output pipe can be
/// either other processing stage or a FIFO sample buffer.
class FIFOProcessor :public FIFOSamplePipe
{
protected:
    /// Internal pipe where processed samples are put.
    FIFOSamplePipe *output;

    /// Sets output pipe.
    void setOutPipe(FIFOSamplePipe *pOutput)
    {
        assert(output == NULL);
        assert(pOutput != NULL);
        output = pOutput;
    }


    /// Constructor. Doesn't define output pipe; it has to be set be 
    /// 'setOutPipe' function.
    FIFOProcessor()
    {
        output = NULL;
    }


    /// Constructor. Configures output pipe.
    FIFOProcessor(FIFOSamplePipe *pOutput   ///< Output pipe.
                 )
    {
        output = pOutput;
    }


    /// Destructor.
    virtual ~FIFOProcessor()
    {
    }


    /// Returns a pointer to the beginning of the output samples. 
    /// This function is provided for accessing the output samples directly. 
    /// Please be careful for not to corrupt the book-keeping!
    ///
    /// When using this function to output samples, also remember to 'remove' the
    /// output samples from the buffer by calling the 
    /// 'receiveSamples(numSamples)' function
    virtual SAMPLETYPE *ptrBegin()
    {
        return output->ptrBegin();
    }

public:

    /// Output samples from beginning of the sample buffer. Copies requested samples to 
    /// output buffer and removes them from the sample buffer. If there are less than 
    /// 'numsample' samples in the buffer, returns all that available.
    ///
    /// \return Number of samples returned.
    virtual uint receiveSamples(SAMPLETYPE *outBuffer, ///< Buffer where to copy output samples.
                                uint maxSamples                    ///< How many samples to receive at max.
                                )
    {
        return output->receiveSamples(outBuffer, maxSamples);
    }


    /// Adjusts book-keeping so that given number of samples are removed from beginning of the 
    /// sample buffer without copying them anywhere. 
    ///
    /// Used to reduce the number of samples in the buffer when accessing the sample buffer directly
    /// with 'ptrBegin' function.
    virtual uint receiveSamples(uint maxSamples   ///< Remove this many samples from the beginning of pipe.
                                )
    {
        return output->receiveSamples(maxSamples);
    }


    /// Returns number of samples currently available.
    virtual uint numSamples() const
    {
        return output->numSamples();
    }


    /// Returns nonzero if there aren't any samples available for outputting.
    virtual int isEmpty() const
    {
        return output->isEmpty();
    }

    /// allow trimming (downwards) amount of samples in pipeline.
    /// Returns adjusted amount of samples
    virtual uint adjustAmountOfSamples(uint numSamples)
    {
        return output->adjustAmountOfSamples(numSamples);
    }

};

}

#endif