////////////////////////////////////////////////////////////////////////////////

///

/// The routine detects highest value on an array of values and calculates the 

/// precise peak location as a mass-center of the 'hump' around the peak value.

///

/// Author        : Copyright (c) Olli Parviainen

/// Author e-mail : oparviai 'at' iki.fi

/// SoundTouch WWW: http://www.surina.net/soundtouch

///

////////////////////////////////////////////////////////////////////////////////

//

// Last changed  : $Date: 2008-12-25 19:54:41 +0200 (Thu, 25 Dec 2008) $

// File revision : $Revision: 4 $

//

// $Id: PeakFinder.h 43 2008-12-25 17:54:41Z oparviai $

//

////////////////////////////////////////////////////////////////////////////////

//

// 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 _PeakFinder_H_

#define _PeakFinder_H_



namespace soundtouch

{



class PeakFinder

{

protected:

    /// Min, max allowed peak positions within the data vector

    int minPos, maxPos;



    /// Calculates the mass center between given vector items.

    double calcMassCenter(const float *data, ///< Data vector.

                         int firstPos,      ///< Index of first vector item beloging to the peak.

                         int lastPos        ///< Index of last vector item beloging to the peak.

                         ) const;



    /// Finds the data vector index where the monotoniously decreasing signal crosses the

    /// given level.

    int   findCrossingLevel(const float *data,  ///< Data vector.

                            float level,        ///< Goal crossing level.

                            int peakpos,        ///< Peak position index within the data vector.

                            int direction       /// Direction where to proceed from the peak: 1 = right, -1 = left.

                            ) const;



    /// Finds the 'ground' level, i.e. smallest level between two neighbouring peaks, to right- 

    /// or left-hand side of the given peak position.

    int   findGround(const float *data,     /// Data vector.

                     int peakpos,           /// Peak position index within the data vector.

                     int direction          /// Direction where to proceed from the peak: 1 = right, -1 = left.

                     ) const;



    /// get exact center of peak near given position by calculating local mass of center

    double getPeakCenter(const float *data, int peakpos);



public:

    /// Constructor. 

    PeakFinder();



    /// Detect exact peak position of the data vector by finding the largest peak 'hump'

    /// and calculating the mass-center location of the peak hump.

    ///

    /// \return The location of the largest base harmonic peak hump.

    double detectPeak(const float *data, /// Data vector to be analyzed. The data vector has

                                        /// to be at least 'maxPos' items long.

                     int minPos,        ///< Min allowed peak location within the vector data.

                     int maxPos         ///< Max allowed peak location within the vector data.

                     );

};



}



#endif // _PeakFinder_H_