SimpleGain.h

/*
 *  Gain Functions (header)
 *
 *  File        : SimpleGain.h
 *  Library     : SimpleSource
 *  Version     : 1.12
 *  Class       : 
 *
 *  2006, ChunkWare Music Software, OPEN-SOURCE
 *
 *  Permission is hereby granted, free of charge, to any person obtaining a
 *  copy of this software and associated documentation files (the "Software"),
 *  to deal in the Software without restriction, including without limitation
 *  the rights to use, copy, modify, merge, publish, distribute, sublicense,
 *  and/or sell copies of the Software, and to permit persons to whom the
 *  Software is furnished to do so, subject to the following conditions:
 *
 *  The above copyright notice and this permission notice shall be included in
 *  all copies or substantial portions of the Software.
 *
 *  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 *  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 *  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
 *  THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 *  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 *  FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
 *  DEALINGS IN THE SOFTWARE.
 */
 
 
#ifndef __SIMPLE_GAIN_H__
#define __SIMPLE_GAIN_H__
 
#include "SimpleHeader.h"       // common header
 
namespace chunkware_simple
{
    //-------------------------------------------------------------
    // gain functions
    //-------------------------------------------------------------
 
    // linear -> dB conversion
    static INLINE double lin2dB( double lin ) {
        static const double LOG_2_DB = 8.6858896380650365530225783783321;   // 20 / ln( 10 )
        return log( lin ) * LOG_2_DB;
    }
 
    // dB -> linear conversion
    static INLINE double dB2lin( double dB ) {
        static const double DB_2_LOG = 0.11512925464970228420089957273422;  // ln( 10 ) / 20
        return exp( dB * DB_2_LOG );
    }
 
}   // end namespace chunkware_simple
 
#endif  // end __SIMPLE_GAIN_H__