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<h1 class="title">voicegenerator.cpp Example File</h1>
<span class="small-subtitle">demos/mobile/guitartuner/src/voicegenerator.cpp</span>
<!-- $$$demos/mobile/guitartuner/src/voicegenerator.cpp-description -->
<div class="descr"> <a name="details"></a>
<pre class="cpp"> <span class="comment">/****************************************************************************
**
** Copyright (C) 2015 The Qt Company Ltd.
** Contact: http://www.qt.io/licensing/
**
** 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:
**
** &quot;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 The Qt Company Ltd 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
** &quot;AS IS&quot; 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.&quot;
**
** $QT_END_LICENSE$
**
****************************************************************************/</span>
<span class="preprocessor">#include &quot;voicegenerator.h&quot;</span>
<span class="keyword">const</span> <span class="type">int</span> BufferSizeMilliseconds <span class="operator">=</span> <span class="number">100</span>;
VoiceGenerator<span class="operator">::</span>VoiceGenerator(<span class="keyword">const</span> <span class="type"><a href="qaudioformat.html">QAudioFormat</a></span> <span class="operator">&amp;</span>format<span class="operator">,</span>
<span class="type"><a href="qtglobal.html#qreal-typedef">qreal</a></span> frequency<span class="operator">,</span> <span class="type"><a href="qtglobal.html#qreal-typedef">qreal</a></span> amplitude<span class="operator">,</span>
<span class="type"><a href="qobject.html">QObject</a></span> <span class="operator">*</span>parent) :
<span class="type"><a href="qiodevice.html">QIODevice</a></span>(parent)<span class="operator">,</span>
m_format(format)<span class="operator">,</span>
m_amplitude(<span class="number">0.5</span>)
{
Q_ASSERT(m_format<span class="operator">.</span>sampleSize() <span class="operator">%</span> <span class="number">8</span> <span class="operator">=</span><span class="operator">=</span> <span class="number">0</span>);
<span class="type">int</span> sampleBytes <span class="operator">=</span> m_format<span class="operator">.</span>channels() <span class="operator">*</span> (m_format<span class="operator">.</span>sampleSize() <span class="operator">/</span> <span class="number">8</span>);
<span class="comment">// + 1 to round up, just to be sure that all samples fit.</span>
<span class="type"><a href="qtglobal.html#qint64-typedef">qint64</a></span> samplesInBuffer <span class="operator">=</span> m_format<span class="operator">.</span>sampleRate()
<span class="operator">*</span> BufferSizeMilliseconds <span class="operator">/</span> <span class="number">1000</span> <span class="operator">+</span> <span class="number">1</span>;
<span class="type"><a href="qtglobal.html#qint64-typedef">qint64</a></span> length <span class="operator">=</span> samplesInBuffer <span class="operator">*</span> sampleBytes;
m_buffer<span class="operator">.</span>resize(length);
m_max_position <span class="operator">=</span> <span class="number">0</span>;
m_position <span class="operator">=</span> <span class="number">0</span>;
m_amplitude <span class="operator">=</span> amplitude;
setFrequency(frequency);
}
VoiceGenerator<span class="operator">::</span><span class="operator">~</span>VoiceGenerator()
{
}
<span class="comment">/**
* Opens the parent QIODevice.
*/</span>
<span class="type">void</span> VoiceGenerator<span class="operator">::</span>start()
{
open(<span class="type"><a href="qiodevice.html">QIODevice</a></span><span class="operator">::</span>ReadOnly);
}
<span class="comment">/**
* Closes the parent QIODevice. Resets the m_position to zero.
*/</span>
<span class="type">void</span> VoiceGenerator<span class="operator">::</span>stop()
{
close();
m_position <span class="operator">=</span> <span class="number">0</span>;
}
<span class="comment">/**
* Sets the frequency to new frequency.
*/</span>
<span class="type">void</span> VoiceGenerator<span class="operator">::</span>setFrequency(<span class="type"><a href="qtglobal.html#qreal-typedef">qreal</a></span> frequency)
{
Q_ASSERT(<span class="number">1</span> <span class="operator">/</span> frequency <span class="operator">&lt;</span> BufferSizeMilliseconds);
<span class="keyword">this</span><span class="operator">-</span><span class="operator">&gt;</span>m_frequency <span class="operator">=</span> frequency;
refreshData();
}
<span class="comment">/**
* Sets the amplitude for the voice.
*/</span>
<span class="type">void</span> VoiceGenerator<span class="operator">::</span>setAmplitude(<span class="type"><a href="qtglobal.html#qreal-typedef">qreal</a></span> amplitude)
{
Q_ASSERT(amplitude <span class="operator">&gt;</span><span class="operator">=</span> <span class="number">0</span>);
m_amplitude <span class="operator">=</span> amplitude;
refreshData();
}
<span class="comment">/**
* Returns the current frequency.
*/</span>
<span class="type"><a href="qtglobal.html#qreal-typedef">qreal</a></span> VoiceGenerator<span class="operator">::</span>frequency()
{
<span class="keyword">return</span> m_frequency;
}
<span class="comment">/**
* Generates voice data corresponding a sine voice with target frequency.
* The number of data generated is calculated
* and stored to m_max_position.
*/</span>
<span class="type">void</span> VoiceGenerator<span class="operator">::</span>refreshData()
{
<span class="keyword">const</span> <span class="type">int</span> channelBytes <span class="operator">=</span> m_format<span class="operator">.</span>sampleSize() <span class="operator">/</span> <span class="number">8</span>;
<span class="keyword">const</span> <span class="type">int</span> sampleSize <span class="operator">=</span> m_format<span class="operator">.</span>channels() <span class="operator">*</span> channelBytes;
<span class="keyword">const</span> <span class="type"><a href="qtglobal.html#qint64-typedef">qint64</a></span> voiceOscillationsInBuffer <span class="operator">=</span> BufferSizeMilliseconds
<span class="operator">*</span> m_frequency <span class="operator">/</span> <span class="number">1000</span>;
<span class="keyword">const</span> <span class="type"><a href="qtglobal.html#qint64-typedef">qint64</a></span> voiceSamplesInBuffer <span class="operator">=</span> voiceOscillationsInBuffer
<span class="operator">*</span> m_format<span class="operator">.</span>sampleRate() <span class="operator">/</span> m_frequency;
m_max_position <span class="operator">=</span> voiceSamplesInBuffer <span class="operator">*</span> sampleSize;
<span class="type"><a href="qtglobal.html#qint64-typedef">qint64</a></span> dataGenerationLength <span class="operator">=</span> m_buffer<span class="operator">.</span>size();
Q_ASSERT(m_max_position <span class="operator">%</span> (sampleSize) <span class="operator">=</span><span class="operator">=</span> <span class="number">0</span>);
Q_ASSERT(dataGenerationLength <span class="operator">&lt;</span><span class="operator">=</span> m_buffer<span class="operator">.</span>size());
<span class="type">short</span> <span class="operator">*</span>t <span class="operator">=</span> (<span class="type">short</span><span class="operator">*</span>)m_buffer<span class="operator">.</span>data();
<span class="comment">/*
int te ;
static float fpos = 0.0f;
//dataGenerationLength&gt;&gt;=1; // in words
for (int f=0; f&lt;dataGenerationLength; f++) {
te = (short)((sinf(fpos))* (65536.0f/2.0f));
fpos += m_frequency/2000.0f;
t[f]= te;
};
m_amplitude = 1.0f; */</span>
<span class="type"><a href="qtglobal.html#uchar-typedef">uchar</a></span> <span class="operator">*</span>ptr <span class="operator">=</span> <span class="keyword">reinterpret_cast</span><span class="operator">&lt;</span><span class="type"><a href="qtglobal.html#uchar-typedef">uchar</a></span> <span class="operator">*</span><span class="operator">&gt;</span>(m_buffer<span class="operator">.</span>data());
<span class="type">int</span> sampleIndex <span class="operator">=</span> <span class="number">0</span>;
<span class="keyword">while</span> (dataGenerationLength <span class="operator">&gt;</span> <span class="number">0</span>) {
<span class="type"><a href="qtglobal.html#qreal-typedef">qreal</a></span> realValue <span class="operator">=</span> <span class="number">0</span>;
<span class="keyword">if</span> (sampleIndex <span class="operator">&lt;</span> voiceSamplesInBuffer) {
realValue <span class="operator">=</span> m_amplitude
<span class="operator">*</span><a href="qtcore-qmath-h.html#qSin">qSin</a>(<span class="number">2.0f</span> <span class="operator">*</span> M_PI <span class="operator">*</span> m_frequency
<span class="operator">*</span> <span class="type"><a href="qtglobal.html#qreal-typedef">qreal</a></span>(sampleIndex <span class="operator">%</span> m_format<span class="operator">.</span>sampleRate())
<span class="operator">/</span> m_format<span class="operator">.</span>sampleRate());
}
<span class="keyword">for</span> (<span class="type">int</span> i<span class="operator">=</span><span class="number">0</span>; i<span class="operator">&lt;</span>m_format<span class="operator">.</span>channels(); <span class="operator">+</span><span class="operator">+</span>i) {
setValue(ptr<span class="operator">,</span> realValue);
ptr <span class="operator">+</span><span class="operator">=</span> channelBytes;
dataGenerationLength <span class="operator">-</span><span class="operator">=</span> channelBytes;
}
<span class="operator">+</span><span class="operator">+</span>sampleIndex;
}
}
<span class="comment">/**
* Stores the realValue into bytes pointed by ptr as an int value.
* Align-safe.
*/</span>
<span class="type">void</span> VoiceGenerator<span class="operator">::</span>setValue(<span class="type"><a href="qtglobal.html#uchar-typedef">uchar</a></span> <span class="operator">*</span>ptr<span class="operator">,</span> <span class="type"><a href="qtglobal.html#qreal-typedef">qreal</a></span> realValue) {
<span class="keyword">if</span> (m_format<span class="operator">.</span>sampleSize() <span class="operator">=</span><span class="operator">=</span> <span class="number">8</span>)
{
<span class="type"><a href="qtglobal.html#quint8-typedef">quint8</a></span> value <span class="operator">=</span> <span class="number">0</span>;
<span class="keyword">if</span> (m_format<span class="operator">.</span>sampleType() <span class="operator">=</span><span class="operator">=</span> <span class="type"><a href="qaudioformat.html">QAudioFormat</a></span><span class="operator">::</span>UnSignedInt) {
value <span class="operator">=</span> <span class="keyword">static_cast</span><span class="operator">&lt;</span><span class="type"><a href="qtglobal.html#quint8-typedef">quint8</a></span><span class="operator">&gt;</span>(
<a href="qtglobal.html#qRound">qRound</a>((<span class="number">1.0</span> <span class="operator">+</span> realValue) <span class="operator">/</span> <span class="number">2</span>
<span class="operator">*</span> M_MAX_AMPLITUDE_8BIT_UNSIGNED));
} <span class="keyword">else</span> <span class="keyword">if</span> (m_format<span class="operator">.</span>sampleType() <span class="operator">=</span><span class="operator">=</span> <span class="type"><a href="qaudioformat.html">QAudioFormat</a></span><span class="operator">::</span>SignedInt) {
value <span class="operator">=</span> <span class="keyword">static_cast</span><span class="operator">&lt;</span><span class="type"><a href="qtglobal.html#qint8-typedef">qint8</a></span><span class="operator">&gt;</span>(
<a href="qtglobal.html#qRound">qRound</a>(realValue
<span class="operator">*</span> M_MAX_AMPLITUDE_8BIT_SIGNED));
}
<span class="operator">*</span><span class="keyword">reinterpret_cast</span><span class="operator">&lt;</span><span class="type"><a href="qtglobal.html#quint8-typedef">quint8</a></span><span class="operator">*</span><span class="operator">&gt;</span>(ptr) <span class="operator">=</span> value;
} <span class="keyword">else</span> <span class="keyword">if</span> (m_format<span class="operator">.</span>sampleSize() <span class="operator">=</span><span class="operator">=</span> <span class="number">16</span>) {
<span class="type"><a href="qtglobal.html#quint16-typedef">quint16</a></span> value <span class="operator">=</span> <span class="number">0</span>;
<span class="keyword">if</span> (m_format<span class="operator">.</span>sampleType() <span class="operator">=</span><span class="operator">=</span> <span class="type"><a href="qaudioformat.html">QAudioFormat</a></span><span class="operator">::</span>UnSignedInt) {
value <span class="operator">=</span> <span class="keyword">static_cast</span><span class="operator">&lt;</span><span class="type"><a href="qtglobal.html#quint16-typedef">quint16</a></span><span class="operator">&gt;</span>(
<a href="qtglobal.html#qRound">qRound</a>((<span class="number">1.0</span> <span class="operator">+</span> realValue) <span class="operator">/</span> <span class="number">2</span>
<span class="operator">*</span> M_MAX_AMPLITUDE_16BIT_UNSIGNED));
} <span class="keyword">else</span> <span class="keyword">if</span> (m_format<span class="operator">.</span>sampleType() <span class="operator">=</span><span class="operator">=</span> <span class="type"><a href="qaudioformat.html">QAudioFormat</a></span><span class="operator">::</span>SignedInt) {
value <span class="operator">=</span> <span class="keyword">static_cast</span><span class="operator">&lt;</span><span class="type"><a href="qtglobal.html#qint16-typedef">qint16</a></span><span class="operator">&gt;</span>(
<a href="qtglobal.html#qRound">qRound</a>(realValue
<span class="operator">*</span> M_MAX_AMPLITUDE_16BIT_SIGNED));
}
<span class="keyword">if</span> (m_format<span class="operator">.</span>byteOrder() <span class="operator">=</span><span class="operator">=</span> <span class="type"><a href="qaudioformat.html">QAudioFormat</a></span><span class="operator">::</span>LittleEndian)
<a href="qtendian.html#qToLittleEndian">qToLittleEndian</a><span class="operator">&lt;</span><span class="type"><a href="qtglobal.html#qint16-typedef">qint16</a></span><span class="operator">&gt;</span>(value<span class="operator">,</span> ptr);
<span class="keyword">else</span>
<a href="qtendian.html#qToBigEndian">qToBigEndian</a><span class="operator">&lt;</span><span class="type"><a href="qtglobal.html#qint16-typedef">qint16</a></span><span class="operator">&gt;</span>(value<span class="operator">,</span> ptr);
}
}
<span class="type"><a href="qtglobal.html#qint64-typedef">qint64</a></span> VoiceGenerator<span class="operator">::</span>bytesAvailable() <span class="keyword">const</span>
{
<span class="keyword">return</span> m_max_position <span class="operator">+</span> <span class="type"><a href="qiodevice.html">QIODevice</a></span><span class="operator">::</span>bytesAvailable();
}
<span class="comment">/**
* Called by the QIODevice. Puts maxlen amount of voice
* samples into the data array.
*/</span>
<span class="type"><a href="qtglobal.html#qint64-typedef">qint64</a></span> VoiceGenerator<span class="operator">::</span>readData(<span class="type">char</span> <span class="operator">*</span>data<span class="operator">,</span> <span class="type"><a href="qtglobal.html#qint64-typedef">qint64</a></span> maxlen)
{
<span class="type"><a href="qtglobal.html#qint64-typedef">qint64</a></span> total <span class="operator">=</span> <span class="number">0</span>;
<span class="type"><a href="qtglobal.html#qint64-typedef">qint64</a></span> chunk <span class="operator">=</span> <span class="number">0</span>;
<span class="keyword">while</span> (total <span class="operator">&lt;</span> maxlen) {
<span class="keyword">if</span> (maxlen <span class="operator">-</span> total <span class="operator">&gt;</span><span class="operator">=</span> m_max_position <span class="operator">-</span> m_position) {
<span class="comment">// the needed buffer is longer than the currently</span>
<span class="comment">// available buffer from m_position to the m_max_position</span>
chunk <span class="operator">=</span> m_max_position <span class="operator">-</span> m_position;
memcpy(data<span class="operator">,</span> m_buffer<span class="operator">.</span>constData() <span class="operator">+</span> m_position<span class="operator">,</span> chunk);
m_position <span class="operator">=</span> <span class="number">0</span>;
}
<span class="keyword">else</span> {
<span class="comment">// we can copy the needed data directly, and the loop will end</span>
chunk <span class="operator">=</span> maxlen <span class="operator">-</span> total;
memcpy(data<span class="operator">,</span> m_buffer<span class="operator">.</span>constData() <span class="operator">+</span> m_position<span class="operator">,</span> chunk);
m_position <span class="operator">=</span> (m_position <span class="operator">+</span> chunk) <span class="operator">%</span> m_max_position;
}
data <span class="operator">+</span><span class="operator">=</span> chunk;
total <span class="operator">+</span><span class="operator">=</span> chunk;
}
<span class="keyword">return</span> total;
}
<span class="comment">/**
* Empty implementation for writeData, since no data is provided
* for the VoiceGenerator class.
*/</span>
<span class="type"><a href="qtglobal.html#qint64-typedef">qint64</a></span> VoiceGenerator<span class="operator">::</span>writeData(<span class="keyword">const</span> <span class="type">char</span> <span class="operator">*</span>data<span class="operator">,</span> <span class="type"><a href="qtglobal.html#qint64-typedef">qint64</a></span> maxlen)
{
Q_UNUSED(data);
Q_UNUSED(maxlen);
<span class="keyword">return</span> <span class="number">0</span>;
}</pre>
</div>
<!-- @@@demos/mobile/guitartuner/src/voicegenerator.cpp -->
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