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diff --git a/demos/mobile/guitartuner/src/fastfouriertransformer.cpp b/demos/mobile/guitartuner/src/fastfouriertransformer.cpp
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+/****************************************************************************
+**
+** Copyright (C) 2012 Nokia Corporation and/or its subsidiary(-ies).
+** All rights reserved.
+** Contact: Nokia Corporation (qt-info@nokia.com)
+**
+** This file is part of the QtDeclarative module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:BSD$
+** You may use this file under the terms of the BSD license as follows:
+**
+** "Redistribution and use in source and binary forms, with or without
+** modification, are permitted provided that the following conditions are
+** met:
+**   * Redistributions of source code must retain the above copyright
+**     notice, this list of conditions and the following disclaimer.
+**   * Redistributions in binary form must reproduce the above copyright
+**     notice, this list of conditions and the following disclaimer in
+**     the documentation and/or other materials provided with the
+**     distribution.
+**   * Neither the name of Nokia Corporation and its Subsidiary(-ies) nor
+**     the names of its contributors may be used to endorse or promote
+**     products derived from this software without specific prior written
+**     permission.
+**
+** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include "fastfouriertransformer.h"
+#include "math.h"
+
+#define STIN  inline
+#define __STATIC
+
+#include "fftpack.c"
+
+// called by __ogg_fdrffti
+__STATIC void drfti1(int n, float *wa, int *ifac);
+void __ogg_fdrffti(int n, float *wsave, int *ifac);
+void __ogg_fdcosqi(int n, float *wsave, int *ifac);
+// called by drftf1
+STIN void dradf2(int ido,int l1,float *cc,float *ch,float *wa1);
+// called by drftf1
+STIN void dradf4(int ido,int l1,float *cc,float *ch,float *wa1,
+        float *wa2,float *wa3);
+// called by drftf1
+STIN void dradfg(int ido,int ip,int l1,int idl1,float *cc,float *c1,
+        float *c2,float *ch,float *ch2,float *wa);
+// called by drftf1
+STIN void drftf1(int n,float *c,float *ch,float *wa,int *ifac);
+void __ogg_fdrfftf(int n,float *r,float *wsave,int *ifac);
+STIN void dcsqf1(int n,float *x,float *w,float *xh,int *ifac);
+void __ogg_fdcosqf(int n,float *x,float *wsave,int *ifac);
+STIN void dradb2(int ido,int l1,float *cc,float *ch,float *wa1);
+STIN void dradb3(int ido,int l1,float *cc,float *ch,float *wa1,
+                          float *wa2);
+STIN void dradb4(int ido,int l1,float *cc,float *ch,float *wa1,
+        float *wa2,float *wa3);
+STIN void dradbg(int ido,int ip,int l1,int idl1,float *cc,float *c1,
+            float *c2,float *ch,float *ch2,float *wa);
+STIN void drftb1(int n, float *c, float *ch, float *wa, int *ifac);
+void __ogg_fdrfftb(int n, float *r, float *wsave, int *ifac);
+STIN void dcsqb1(int n,float *x,float *w,float *xh,int *ifac);
+void __ogg_fdcosqb(int n,float *x,float *wsave,int *ifac);
+
+FastFourierTransformer::FastFourierTransformer(QObject *parent) :
+        QObject(parent),
+        m_waveFloat(0),
+        m_workingArray(0),
+        m_ifac(0),
+        m_last_n(-1)
+{
+}
+
+FastFourierTransformer::~FastFourierTransformer()
+{
+    if (m_waveFloat != 0) {
+        delete [] m_waveFloat;
+    }
+    if (m_workingArray != 0) {
+       delete [] m_workingArray;
+    }
+    if (m_ifac != 0) {
+        delete [] m_ifac;
+    }
+}
+
+/**
+  * Prepares the arrays to be of length n.
+  */
+void FastFourierTransformer::reserve(int n)
+{
+    Q_ASSERT(n>0);
+    if (m_waveFloat != 0) {
+        delete [] m_waveFloat;
+    }
+    if (m_workingArray != 0) {
+       delete [] m_workingArray;
+    }
+    if (m_ifac != 0) {
+        delete [] m_ifac;
+    }
+    m_workingArray = new float[2*n+15];
+    m_waveFloat = new float[n];
+    m_ifac = new int[n];
+    __ogg_fdrffti(n, m_workingArray, m_ifac);
+    m_last_n = n;
+}
+
+/**
+  * Calculates the Fast Fourier Transformation (FFT).
+  */
+void FastFourierTransformer::calculateFFT(QList<qint16> wave)
+{
+    const int n = wave.size();
+    if (m_last_n != n) {
+        reserve(n);
+    }
+    for (int i = 0; i < n; i++) {
+        m_waveFloat[i] = (float) wave.at(i);
+    }
+
+    __ogg_fdrfftf(n, m_waveFloat, m_workingArray, m_ifac);
+
+}
+
+/**
+  * Returns the index which corresponds to the maximum density
+  * of the FFT.
+  */
+int FastFourierTransformer::getMaximumDensityIndex()
+{
+    const int halfN = m_last_n / 2;
+    float maxDensity = 0;
+    int maxDensityIndex = 0;
+    float densitySquared = 0.f;
+    for (int k = 1; k < halfN; k++) {
+        // Here, we calculate the frequency k/N.
+        // k=1, the wave oscillation time is N, and the frequency
+        //      is 1/sample.
+        // k=2, the wave oscillation time is N/2, and the frequency
+        //      is 2/sample.
+        // k=3, the wave oscillation time is N/3, and the frequency
+        //      is 3/sample.
+        // Note, that the documentation is for Fortran, so indexes in the
+        // documentation does not match.
+        // The sine and cosine coefficients are obtained thus as follows:
+        const float cosCoefficient = qAbs(m_waveFloat[2*k-1]);
+        const float sinCoefficient = qAbs(m_waveFloat[2*k]);
+
+        densitySquared = sinCoefficient*sinCoefficient + cosCoefficient*cosCoefficient;
+        if (densitySquared > maxDensity) {
+            maxDensity = densitySquared;
+            maxDensityIndex = k;
+        }
+    }
+
+    if (m_cutOffForDensitySquared < maxDensity) {
+        return maxDensityIndex;
+    }
+    else {
+        return -1;
+    }
+}
+
+/**
+  * Sets the cutoff density.
+  */
+void FastFourierTransformer::setCutOffForDensity(float cutoff)
+{
+    m_cutOffForDensitySquared = cutoff*cutoff;
+}