73 lines
1.5 KiB
C++
73 lines
1.5 KiB
C++
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#include "circularbuffer.h"
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#include <math.h>
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CircularBuffer::CircularBuffer( double interval, size_t numPoints ):
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d_y( NULL ),
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d_referenceTime( 0.0 ),
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d_startIndex( 0 ),
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d_offset( 0.0 )
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{
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fill( interval, numPoints );
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}
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void CircularBuffer::fill( double interval, size_t numPoints )
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{
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if ( interval <= 0.0 || numPoints < 2 )
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return;
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d_values.resize( numPoints );
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d_values.fill( 0.0 );
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if ( d_y )
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{
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d_step = interval / ( numPoints - 2 );
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for ( size_t i = 0; i < numPoints; i++ )
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d_values[i] = d_y( i * d_step );
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}
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d_interval = interval;
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}
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void CircularBuffer::setFunction( double( *y )( double ) )
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{
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d_y = y;
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}
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void CircularBuffer::setReferenceTime( double timeStamp )
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{
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d_referenceTime = timeStamp;
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const double startTime = ::fmod( d_referenceTime, d_values.size() * d_step );
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d_startIndex = int( startTime / d_step ); // floor
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d_offset = ::fmod( startTime, d_step );
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}
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double CircularBuffer::referenceTime() const
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{
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return d_referenceTime;
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}
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size_t CircularBuffer::size() const
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{
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return d_values.size();
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}
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QPointF CircularBuffer::sample( size_t i ) const
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{
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const int size = d_values.size();
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int index = d_startIndex + i;
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if ( index >= size )
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index -= size;
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const double x = i * d_step - d_offset - d_interval;
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const double y = d_values.data()[index];
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return QPointF( x, y );
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}
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QRectF CircularBuffer::boundingRect() const
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{
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return QRectF( -1.0, -d_interval, 2.0, d_interval );
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}
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