pixel column counts and sample window sizes use unsigned types

src/Spectrum.cpp

@@ -20,8 +20,8 @@
 
 #include "Experimental.h"
 
-bool ComputeSpectrum(const float * data, int width,
-                     int windowSize,
+bool ComputeSpectrum(const float * data, size_t width,
+                     size_t windowSize,
                      double WXUNUSED(rate), float *output,
                      bool autocorrelation, int windowFunc)
 {
@@ -33,19 +33,18 @@ bool ComputeSpectrum(const float * data, int width,
 
    float *processed = new float[windowSize];
 
-   int i;
-   for (i = 0; i < windowSize; i++)
+   for (size_t i = 0; i < windowSize; i++)
       processed[i] = float(0.0);
-   int half = windowSize / 2;
+   auto half = windowSize / 2;
 
    float *in = new float[windowSize];
    float *out = new float[windowSize];
    float *out2 = new float[windowSize];
 
-   int start = 0;
-   int windows = 0;
+   size_t start = 0;
+   unsigned windows = 0;
    while (start + windowSize <= width) {
-      for (i = 0; i < windowSize; i++)
+      for (size_t i = 0; i < windowSize; i++)
          in[i] = data[start + i];
 
       WindowFunc(windowFunc, windowSize, in);
@@ -54,13 +53,13 @@ bool ComputeSpectrum(const float * data, int width,
          // Take FFT
          RealFFT(windowSize, in, out, out2);
          // Compute power
-         for (i = 0; i < windowSize; i++)
+         for (size_t i = 0; i < windowSize; i++)
             in[i] = (out[i] * out[i]) + (out2[i] * out2[i]);
 
          // Tolonen and Karjalainen recommend taking the cube root
          // of the power, instead of the square root
 
-         for (i = 0; i < windowSize; i++)
+         for (size_t i = 0; i < windowSize; i++)
             in[i] = powf(in[i], 1.0f / 3.0f);
 
          // Take FFT
@@ -70,7 +69,7 @@ bool ComputeSpectrum(const float * data, int width,
          PowerSpectrum(windowSize, in, out);
 
       // Take real part of result
-      for (i = 0; i < half; i++)
+      for (size_t i = 0; i < half; i++)
         processed[i] += out[i];
 
       start += half;
@@ -85,7 +84,7 @@ bool ComputeSpectrum(const float * data, int width,
        It should be safe, as indexes refer only to current and previous elements,
        that have already been clipped, etc...
       */
-      for (i = 0; i < half; i++) {
+      for (size_t i = 0; i < half; i++) {
         // Clip at zero, copy to temp array
         if (processed[i] < 0.0)
             processed[i] = float(0.0);
@@ -103,23 +102,23 @@ bool ComputeSpectrum(const float * data, int width,
       }
 
       // Reverse and scale
-      for (i = 0; i < half; i++)
+      for (size_t i = 0; i < half; i++)
          in[i] = processed[i] / (windowSize / 4);
-      for (i = 0; i < half; i++)
+      for (size_t i = 0; i < half; i++)
          processed[half - 1 - i] = in[i];
    } else {
       // Convert to decibels
       // But do it safely; -Inf is nobody's friend
-      for (i = 0; i < half; i++){
+      for (size_t i = 0; i < half; i++){
          float temp=(processed[i] / windowSize / windows);
          if (temp > 0.0)
-            processed[i] = 10*log10(temp);
+            processed[i] = 10 * log10(temp);
          else
             processed[i] = 0;
       }
    }
 
-   for(i=0;i<half;i++)
+   for(size_t i = 0; i < half; i++)
       output[i] = processed[i];
    delete[]in;
    delete[]out;