Code cleanup: Changed a few pointers to const pointers in FFT code

Author: RaphaelMarinier

src/FFT.cpp

@@ -137,7 +137,8 @@ inline int FastReverseBits(int i, int NumBits)
 
 void FFT(int NumSamples,
          bool InverseTransform,
-         float *RealIn, float *ImagIn, float *RealOut, float *ImagOut)
+         const float *RealIn, const float *ImagIn,
+	 float *RealOut, float *ImagOut)
 {
    int NumBits;                 /* Number of bits needed to store indices */
    int i, j, k, n;
@@ -236,7 +237,7 @@ void FFT(int NumSamples,
  * This is merely a wrapper of RealFFTf() from RealFFTf.h.
  */
 
-void RealFFT(int NumSamples, float *RealIn, float *RealOut, float *ImagOut)
+void RealFFT(int NumSamples, const float *RealIn, float *RealOut, float *ImagOut)
 {
    int i;
    HFFT hFFT = GetFFT(NumSamples);
@@ -277,7 +278,8 @@ void RealFFT(int NumSamples, float *RealIn, float *RealOut, float *ImagOut)
  *
  * This is merely a wrapper of InverseRealFFTf() from RealFFTf.h.
  */
-void InverseRealFFT(int NumSamples, float *RealIn, float *ImagIn, float *RealOut)
+void InverseRealFFT(int NumSamples, const float *RealIn, const float *ImagIn,
+		    float *RealOut)
 {
    int i;
    HFFT hFFT = GetFFT(NumSamples);
@@ -316,7 +318,7 @@ void InverseRealFFT(int NumSamples, float *RealIn, float *ImagIn, float *RealOut
  * of its code.
  */
 
-void PowerSpectrum(int NumSamples, float *In, float *Out)
+void PowerSpectrum(int NumSamples, const float *In, float *Out)
 {
    int i;
    HFFT hFFT = GetFFT(NumSamples);

src/FFT.h

@@ -61,7 +61,7 @@
  * input array, and that NumSamples must be a power of two.
  */
 
-void PowerSpectrum(int NumSamples, float *In, float *Out);
+void PowerSpectrum(int NumSamples, const float *In, float *Out);
 
 /*
  * Computes an FFT when the input data is real but you still
@@ -71,15 +71,15 @@ void PowerSpectrum(int NumSamples, float *In, float *Out);
  */
 
 void RealFFT(int NumSamples,
-             float *RealIn, float *RealOut, float *ImagOut);
+             const float *RealIn, float *RealOut, float *ImagOut);
 
 /*
  * Computes an Inverse FFT when the input data is conjugate symmetric
  * so the output is purely real.  NumSamples must be a power of
  * two.
  */
 void InverseRealFFT(int NumSamples,
-             float *RealIn, float *ImagIn, float *RealOut);
+		    const float *RealIn, const float *ImagIn, float *RealOut);
 
 /*
  * Computes a FFT of complex input and returns complex output.
@@ -89,7 +89,7 @@ void InverseRealFFT(int NumSamples,
 
 void FFT(int NumSamples,
          bool InverseTransform,
-         float *RealIn, float *ImagIn, float *RealOut, float *ImagOut);
+         const float *RealIn, const float *ImagIn, float *RealOut, float *ImagOut);
 
 /*
  * Multiply values in data by values of the chosen function

src/RealFFTf.cpp

@@ -191,9 +191,9 @@ void CleanupFFT()
 void RealFFTf(fft_type *buffer,HFFT h)
 {
    fft_type *A,*B;
-   fft_type *sptr;
-   fft_type *endptr1,*endptr2;
-   int *br1,*br2;
+   const fft_type *sptr;
+   const fft_type *endptr1,*endptr2;
+   const int *br1,*br2;
    fft_type HRplus,HRminus,HIplus,HIminus;
    fft_type v1,v2,sin,cos;
 
@@ -293,9 +293,9 @@ void RealFFTf(fft_type *buffer,HFFT h)
 void InverseRealFFTf(fft_type *buffer,HFFT h)
 {
    fft_type *A,*B;
-   fft_type *sptr;
-   fft_type *endptr1,*endptr2;
-   int *br1;
+   const fft_type *sptr;
+   const fft_type *endptr1,*endptr2;
+   const int *br1;
    fft_type HRplus,HRminus,HIplus,HIminus;
    fft_type v1,v2,sin,cos;
 
@@ -373,7 +373,8 @@ void InverseRealFFTf(fft_type *buffer,HFFT h)
    }
 }
 
-void ReorderToFreq(HFFT hFFT, fft_type *buffer, fft_type *RealOut, fft_type *ImagOut)
+void ReorderToFreq(HFFT hFFT, const fft_type *buffer,
+		   fft_type *RealOut, fft_type *ImagOut)
 {
    // Copy the data into the real and imaginary outputs
    for(int i=1;i<hFFT->Points;i++) {
@@ -386,7 +387,7 @@ void ReorderToFreq(HFFT hFFT, fft_type *buffer, fft_type *RealOut, fft_type *Ima
    ImagOut[hFFT->Points] = 0;
 }
 
-void ReorderToTime(HFFT hFFT, fft_type *buffer, fft_type *TimeOut)
+void ReorderToTime(HFFT hFFT, const fft_type *buffer, fft_type *TimeOut)
 {
    // Copy the data into the real outputs
    for(int i=0;i<hFFT->Points;i++) {

src/RealFFTf.h

@@ -21,8 +21,9 @@ void ReleaseFFT(HFFT);
 void CleanupFFT();
 void RealFFTf(fft_type *,HFFT);
 void InverseRealFFTf(fft_type *,HFFT);
-void ReorderToTime(HFFT hFFT, fft_type *buffer, fft_type *TimeOut);
-void ReorderToFreq(HFFT hFFT, fft_type *buffer, fft_type *RealOut, fft_type *ImagOut);
+void ReorderToTime(HFFT hFFT, const fft_type *buffer, fft_type *TimeOut);
+void ReorderToFreq(HFFT hFFT, const fft_type *buffer,
+		   fft_type *RealOut, fft_type *ImagOut);
 
 #endif