SimpleLimit.cpp

/*
 *  Simple Limiter (source)
 *
 *  File        : SimpleLimit.cpp
 *  Library     : SimpleSource
 *  Version     : 1.12
 *  Implements  : SimpleLimit
 *
 *  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.
 */
 
 
#include "SimpleLimit.h"
 
namespace chunkware_simple
{
    //-------------------------------------------------------------
    SimpleLimit::SimpleLimit()
        : threshdB_(0.0)
        , thresh_(1.0)
        , peakHold_(0)
        , peakTimer_(0)
        , maxPeak_(1.0)
        , att_(1.0)
        , rel_(10.0)
        , env_(1.0)
        , mask_(BUFFER_SIZE - 1)
        , cur_(0)
    {
        setAttackImpl(1.0);
        outBuffer_[ 0 ].resize(BUFFER_SIZE, 0.0);
        outBuffer_[ 1 ].resize(BUFFER_SIZE, 0.0);
    }
 
    //-------------------------------------------------------------
    void SimpleLimit::setThresh(double dB)
    {
        threshdB_ = dB;
        thresh_ = dB2lin(dB);
    }
 
    //-------------------------------------------------------------
    void SimpleLimit::setAttackImpl(double ms)
    {
        unsigned int samp = static_cast<unsigned>(0.001 * ms * att_.getSampleRate());
 
        assert(samp < BUFFER_SIZE);
 
        peakHold_ = samp;
        att_.setTc(ms);
    }
 
    //-------------------------------------------------------------
    void SimpleLimit::setRelease(double ms)
    {
        rel_.setTc(ms);
    }
 
    //-------------------------------------------------------------
    void SimpleLimit::setSampleRate(double sampleRate)
    {
        att_.setSampleRate(sampleRate);
        rel_.setSampleRate(sampleRate);
    }
 
    //-------------------------------------------------------------
    void SimpleLimit::initRuntime(void)
    {
        peakTimer_ = 0;
        maxPeak_ = thresh_;
        env_ = thresh_;
        cur_ = 0;
        outBuffer_[ 0 ].assign(BUFFER_SIZE, 0.0);
        outBuffer_[ 1 ].assign(BUFFER_SIZE, 0.0);
    }
 
    //-------------------------------------------------------------
    void SimpleLimit::FastEnvelope::setCoef(void)
    {
        // rises to 99% of in value over duration of time constant
        coef_ = pow(0.01, (1000.0 / (ms_ * sampleRate_)));
    }
 
}   // end namespace chunkware_simple