Use common hamming window function code via wmcommon.hh.

Signed-off-by: Stefan Westerfeld <stefan@space.twc.de>

src/TODO

@@ -2,10 +2,8 @@ speed detection:
  - double decode
  - maybe truncate cleanup
  - remove pad start scaling
- - average speed if more than one best-quality 50s estimate is produced
  - test code
  - document in README
- - analyze remaining variants
 
 possible improvements:
 - dynamic bit strength

src/wmcommon.cc

@@ -49,23 +49,6 @@ std::string Params::output_label;
 using std::vector;
 using std::complex;
 
-inline double
-window_cos (double x) /* von Hann window */
-{
-  if (fabs (x) > 1)
-    return 0;
-  return 0.5 * cos (x * M_PI) + 0.5;
-}
-
-inline double
-window_hamming (double x) /* sharp (rectangle) cutoffs at boundaries */
-{
-  if (fabs (x) > 1)
-    return 0;
-
-  return 0.54 + 0.46 * cos (M_PI * x);
-}
-
 /*
  * glibc log2f is a lot faster than glibc log10
  */

src/wmcommon.hh

@@ -168,6 +168,23 @@ randomize_bit_order (const std::vector<T>& bit_vec, bool encode)
   return out_bits;
 }
 
+inline double
+window_cos (double x) /* von Hann window */
+{
+  if (fabs (x) > 1)
+    return 0;
+  return 0.5 * cos (x * M_PI) + 0.5;
+}
+
+inline double
+window_hamming (double x) /* sharp (rectangle) cutoffs at boundaries */
+{
+  if (fabs (x) > 1)
+    return 0;
+
+  return 0.54 + 0.46 * cos (M_PI * x);
+}
+
 int add_stream_watermark (AudioInputStream *in_stream, AudioOutputStream *out_stream, const std::string& bits, size_t zero_frames);
 int add_watermark (const std::string& infile, const std::string& outfile, const std::string& bits);
 int get_watermark (const std::string& infile, const std::string& orig_pattern);

src/wmspeed.cc

@@ -133,17 +133,6 @@ public:
   }
 };
 
-
-/* FIXME: is this the best choice */
-inline double
-window_hamming (double x) /* sharp (rectangle) cutoffs at boundaries */
-{
-  if (fabs (x) > 1)
-    return 0;
-
-  return 0.54 + 0.46 * cos (M_PI * x);
-}
-
 void
 SpeedSync::prepare_mags()
 {
@@ -161,6 +150,7 @@ SpeedSync::prepare_mags()
     {
       const double fsize_2 = sub_frame_size / 2.0;
       // const double win =  window_cos ((i - fsize_2) / fsize_2);
+      /* FIXME: is this the best choice */
       const double win = window_hamming ((i - fsize_2) / fsize_2);
       //const double win = 1;
       window[i] = win;