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58 lines
1.3 KiB
58 lines
1.3 KiB
9 years ago
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#ifndef __RINGBUFFER_H
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#define __RINGBUFFER_H
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#ifdef _MSC_VER
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#define INLINE __forceinline
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#else
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#define INLINE inline
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#endif
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#include <vector>
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// Hermite polynomial interpolation
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INLINE float getSampleHermite4p3o(float x, float *y)
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{
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static float c0, c1, c2, c3;
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// 4-point, 3rd-order Hermite (x-form)
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c0 = y[1];
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c1 = (1.0/2.0)*(y[2]-y[0]);
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c2 = (y[0] - (5.0/2.0)*y[1]) + (2.0*y[2] - (1.0/2.0)*y[3]);
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c3 = (1.0/2.0)*(y[3]-y[0]) + (3.0/2.0)*(y[1]-y[2]);
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return ((c3*x+c2)*x+c1)*x+c0;
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}
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class RingBuffer
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{
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public:
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RingBuffer();
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void write(float sample);
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void write_margined(float sample);
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float readWithDelay(int delay);
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void resize(int size);
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public:
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INLINE float getHermiteAt(float delay)
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{
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float fReadIndex = writeIndex - 1 - delay;
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while(fReadIndex < 0)
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fReadIndex += size;
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while(fReadIndex >= size)
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fReadIndex -= size;
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int iPart = (int)fReadIndex; // integer part of the delay
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float fPart = fReadIndex - iPart; // fractional part of the delay
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return getSampleHermite4p3o(fPart, &(buffer[iPart]));
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}
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private:
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std::vector<float> buffer;
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int writeIndex;
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int size;
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static const int interpolatorMargin = 3;
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};
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#endif
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