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#include "fftcalc.h"
#include "appglobal.h"
#include "logging.h"
#include <string.h>
fftCalc::fftCalc()
{
plan=NULL;
out=NULL;
dataBuffer=NULL;
dataBufferWindowed=NULL;
}
fftCalc::~fftCalc()
{
if(plan)fftw_destroy_plan(plan);
if(out) fftw_free(out);
if(dataBuffer) fftw_free(dataBuffer);
}
void fftCalc::init(int length,int nblocks,int isamplingrate)
{
int i;
windowSize=length;
fftLength=windowSize*nblocks;
numBlocks=nblocks;
blockIndex=0;
createHamming();
samplingrate=isamplingrate;
//prepare fft
if(plan)fftw_destroy_plan(plan);
if(out) fftw_free(out);
if(dataBuffer) delete [] dataBuffer;
dataBuffer=new double[fftLength];
for(i=0;i<fftLength;i++)
{
dataBuffer[i]=0.;
}
if(dataBufferWindowed) fftw_free(dataBufferWindowed);
out = (double *)fftw_malloc(fftLength * sizeof(double));
dataBufferWindowed = (double *)fftw_malloc(fftLength * sizeof(double));
// create the fftw plan
addToLog("fftw_plan fftcalc start",LOGFFT);
plan = fftw_plan_r2r_1d(fftLength, dataBufferWindowed, out, FFTW_R2HC, FFTW_ESTIMATE);
addToLog("fftw_plan fftcalc stop",LOGFFT);
}
void fftCalc::createHamming()
{
int i;
hammingBuffer= new double[fftLength];
for(i=0;i<fftLength;i++)
{
hammingBuffer[i]=0.54-(0.46*cos(2*M_PI*((double)i/((double)(fftLength-1)))));
}
}
void fftCalc::realFFT(double *data)
{
int i;
memmove(&dataBuffer[0],&dataBuffer[windowSize],sizeof(double)*windowSize*(numBlocks-1));
memmove(&dataBuffer[windowSize*(numBlocks-1)],data,sizeof(double)*windowSize);
for(i=0;i<fftLength;i++)
{
dataBufferWindowed[i]=dataBuffer[i]*hammingBuffer[i];
}
fftw_execute(plan);
}
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