fifosamplebuffer.h

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/*****************************************************************************
 *
 * 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 
 * outputted samples from the buffer as well as grows the storage size 
 * whenever necessary.
 *
 * Author        : Copyright (c) Olli Parviainen
 * Author e-mail : oparviai @ iki.fi
 * File created  : 13-Jan-2002
 *
 * Last changed  : $Date: 2004/03/14 15:51:41 $
 * File revision : $Revision: 1.1.1.1 $
 *
 * $Id: FIFOSampleBuffer.h,v 1.1.1.1 2004/03/14 15:51:41 mbrubeck Exp $
 *
 * License :
 * 
 *  SoundTouch sound 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"

/// 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.
    soundtouch::SAMPLETYPE *buffer;

    // Raw unaligned buffer memory. 'buffer' is made aligned by pointing it to first
    // 16-byte aligned location of this buffer
    soundtouch::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(const uint capacityRequirement);

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

    /// Constructor
    FIFOSampleBuffer(uint 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
    /// outputted samples from the buffer by calling the 
    /// 'receiveSamples(numSamples)' function
    virtual soundtouch::SAMPLETYPE *ptrBegin() const;

    /// 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.
    soundtouch::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 soundtouch::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(soundtouch::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(uint numChannels);

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

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

#endif