* Initial import

src/FFT.h

@@ -0,0 +1,70 @@
+/* -*- c-basic-offset: 4 indent-tabs-mode: nil -*-  vi:set ts=8 sts=4 sw=4: */
+
+/*
+    Rubber Band
+    An audio time-stretching and pitch-shifting library.
+    Copyright 2007 Chris Cannam.
+    
+    This program is free software; you can redistribute it and/or
+    modify it under the terms of the GNU General Public License as
+    published by the Free Software Foundation; either version 2 of the
+    License, or (at your option) any later version.  See the file
+    COPYING included with this distribution for more information.
+*/
+
+#ifndef _RUBBERBAND_FFT_H_
+#define _RUBBERBAND_FFT_H_
+
+class FFTImpl;
+
+
+/**
+ * Provide the basic FFT computations we need, using one of a set of
+ * candidate FFT implementations (depending on compile flags).
+ *
+ * Implements real->complex FFTs of power-of-two sizes only.  Note
+ * that only the first half of the output signal is returned (the
+ * complex conjugates half is omitted), so the "complex" arrays need
+ * room for size/2+1 elements.
+ *
+ * Not thread safe: use a separate instance per thread.
+ */
+
+class FFT
+{
+public:
+    enum Exception { InvalidSize };
+
+    FFT(unsigned int size); // may throw InvalidSize
+    ~FFT();
+
+    void forward(double *realIn, double *realOut, double *imagOut);
+    void forwardPolar(double *realIn, double *magOut, double *phaseOut);
+    void forwardMagnitude(double *realIn, double *magOut);
+
+    void forward(float *realIn, float *realOut, float *imagOut);
+    void forwardPolar(float *realIn, float *magOut, float *phaseOut);
+    void forwardMagnitude(float *realIn, float *magOut);
+
+    void inverse(double *realIn, double *imagIn, double *realOut);
+    void inversePolar(double *magIn, double *phaseIn, double *realOut);
+
+    void inverse(float *realIn, float *imagIn, float *realOut);
+    void inversePolar(float *magIn, float *phaseIn, float *realOut);
+
+    // Calling one or both of these is optional -- if neither is
+    // called, the first call to a forward or inverse method will call
+    // init().  You only need call these if you don't want to risk
+    // expensive allocations etc happening in forward or inverse.
+    void initFloat();
+    void initDouble();
+
+    static void tune();
+
+protected:
+    FFTImpl *d;
+    static int m_method;
+};
+
+#endif
+