soundtouch/include/FIFOSampleBuffer.h

////////////////////////////////////////////////////////////////////////////////
///
/// A buffer class for temporarily storaging sound samples, operates as a 
/// first-in-first-out pipe.
///
/// Samples are added to the end of the sample buffer with the 'putSamples' 
/// function, and are received from the beginning of the buffer by calling
/// the 'receiveSamples' function. The class automatically removes the 
/// output samples from the buffer as well as grows the storage size 
/// whenever necessary.
///
/// 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 FIFOSampleBuffer_H
#define FIFOSampleBuffer_H

#include "FIFOSamplePipe.h"

namespace soundtouch
{

/// Sample buffer working in FIFO (first-in-first-out) principle. The class takes
/// care of storage size adjustment and data moving during input/output operations.
///
/// Notice that in case of stereo audio, one sample is considered to consist of 
/// both channel data.
class FIFOSampleBuffer : public FIFOSamplePipe
{
private:
    /// Sample buffer.
    SAMPLETYPE *buffer;

    // Raw unaligned buffer memory. 'buffer' is made aligned by pointing it to first
    // 16-byte aligned location of this buffer
    SAMPLETYPE *bufferUnaligned;

    /// Sample buffer size in bytes
    uint sizeInBytes;

    /// How many samples are currently in buffer.
    uint samplesInBuffer;

    /// Channels, 1=mono, 2=stereo.
    uint channels;

    /// Current position pointer to the buffer. This pointer is increased when samples are 
    /// removed from the pipe so that it's necessary to actually rewind buffer (move data)
    /// only new data when is put to the pipe.
    uint bufferPos;

    /// Rewind the buffer by moving data from position pointed by 'bufferPos' to real 
    /// beginning of the buffer.
    void rewind();

    /// Ensures that the buffer has capacity for at least this many samples.
    void ensureCapacity(uint capacityRequirement);

    /// Returns current capacity.
    uint getCapacity() const;

public:

    /// Constructor
    FIFOSampleBuffer(int numChannels = 2     ///< Number of channels, 1=mono, 2=stereo.
                                              ///< Default is stereo.
                     );

    /// destructor
    ~FIFOSampleBuffer();

    /// 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();

    /// Returns a pointer to the end of the used part of the sample buffer (i.e. 
    /// where the new samples are to be inserted). This function may be used for 
    /// inserting new samples into the sample buffer directly. Please be careful
    /// not corrupt the book-keeping!
    ///
    /// When using this function as means for inserting new samples, also remember 
    /// to increase the sample count afterwards, by calling  the 
    /// 'putSamples(numSamples)' function.
    SAMPLETYPE *ptrEnd(
                uint slackCapacity   ///< How much free capacity (in samples) there _at least_ 
                                     ///< should be so that the caller can succesfully insert the 
                                     ///< desired samples to the buffer. If necessary, the function 
                                     ///< grows the buffer size to comply with this requirement.
                );

    /// 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.
                            );

    /// Adjusts the book-keeping to increase number of samples in the buffer without 
    /// copying any actual samples.
    ///
    /// This function is used to update the number of samples in the sample buffer
    /// when accessing the buffer directly with 'ptrEnd' function. Please be 
    /// careful though!
    virtual void putSamples(uint numSamples   ///< Number of samples been inserted.
                            );

    /// 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.
                                );

    /// 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.
                                );

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

    /// Sets number of channels, 1 = mono, 2 = stereo.
    void setChannels(int numChannels);

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

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

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

}

#endif