Deduplicate speed sync quality computation into one function.

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

src/wmspeed.cc

@@ -141,6 +141,8 @@ private:
   template<bool B2>
   void compare_bits_fft (FFTProcessor& fft_processor, BitValue *bit_values, double relative_speed, double offset);
 
+  double sync_quality (const BitValue *bit_values);
+
   std::mutex mutex;
   vector<Score> result_scores;
   const WavData& in_data;
@@ -402,6 +404,45 @@ SpeedSync::compare_bits_fft (FFTProcessor& fft_processor, BitValue *bit_values,
     }
 }
 
+double
+SpeedSync::sync_quality (const BitValue *bit_values)
+{
+  int bit_count = 0;
+  double quality = 0;
+
+  for (size_t bit = 0; bit < Params::sync_bits; bit++)
+    {
+      const auto& bv = bit_values[bit];
+
+      /* convert avoiding bias, raw_bit < 0 => 0 bit received; raw_bit > 0 => 1 bit received */
+      double raw_bit;
+      if (bv.umag == 0 || bv.dmag == 0)
+        {
+          raw_bit = 0;
+        }
+      else if (bv.umag < bv.dmag)
+        {
+          raw_bit = 1 - bv.umag / bv.dmag;
+        }
+      else
+        {
+          raw_bit = bv.dmag / bv.umag - 1;
+        }
+      const int expect_data_bit = bit & 1; /* expect 010101 */
+      const double q = expect_data_bit ? raw_bit : -raw_bit;
+      quality += q * bv.count;
+      bit_count += bv.count;
+    }
+  if (bit_count)
+    {
+      quality /= bit_count;
+      quality = fabs (quality);
+
+      // quality = fabs (sync_finder.normalize_sync_quality (sync_quality));
+    }
+  return quality;
+}
+
 void
 SpeedSync::compare (double relative_speed, bool final_stage)
 {
@@ -421,44 +462,12 @@ SpeedSync::compare (double relative_speed, bool final_stage)
       compare_bits<false> (bit_values, relative_speed, &start_mi1, offset);
       compare_bits<true>  (bit_values, relative_speed, &start_mi2, offset + frames_per_block * steps_per_frame);
 
-      double sync_quality = 0;
-      int bit_count = 0;
-
-      for (size_t bit = 0; bit < Params::sync_bits; bit++)
-        {
-          const auto& bv = bit_values[bit];
-
-          /* convert avoiding bias, raw_bit < 0 => 0 bit received; raw_bit > 0 => 1 bit received */
-          double raw_bit;
-          if (bv.umag == 0 || bv.dmag == 0)
-            {
-              raw_bit = 0;
-            }
-          else if (bv.umag < bv.dmag)
-            {
-              raw_bit = 1 - bv.umag / bv.dmag;
-            }
-          else
-            {
-              raw_bit = bv.dmag / bv.umag - 1;
-            }
-          const int expect_data_bit = bit & 1; /* expect 010101 */
-          const double q = expect_data_bit ? raw_bit : -raw_bit;
-          sync_quality += q * bv.count;
-          bit_count += bv.count;
-        }
-      if (bit_count)
+      double quality = sync_quality (bit_values);
+      if (quality > best_score.quality)
         {
-          sync_quality /= bit_count;
-          sync_quality = fabs (sync_quality);
-          //sync_quality = fabs (sync_finder.normalize_sync_quality (sync_quality));
-          //printf ("%d %f\n", offset, fabs (sync_quality));
-          if (sync_quality > best_score.quality)
-            {
-              best_score.quality = sync_quality;
-              best_score.speed = relative_speed * center;
-              best_offset = offset;
-            }
+          best_score.quality = quality;
+          best_score.speed = relative_speed * center;
+          best_offset = offset;
         }
     }
   if (final_stage)
@@ -477,43 +486,11 @@ SpeedSync::compare (double relative_speed, bool final_stage)
           compare_bits_fft<false> (fft_processor, bit_values, relative_speed, doffset);
           compare_bits_fft<true>  (fft_processor, bit_values, relative_speed, doffset + frames_per_block * steps_per_frame);
 
-          double sync_quality = 0;
-          int bit_count = 0;
-
-          for (size_t bit = 0; bit < Params::sync_bits; bit++)
+          double quality = sync_quality (bit_values);
+          if (quality > best_score.quality)
             {
-              const auto& bv = bit_values[bit];
-
-              /* convert avoiding bias, raw_bit < 0 => 0 bit received; raw_bit > 0 => 1 bit received */
-              double raw_bit;
-              if (bv.umag == 0 || bv.dmag == 0)
-                {
-                  raw_bit = 0;
-                }
-              else if (bv.umag < bv.dmag)
-                {
-                  raw_bit = 1 - bv.umag / bv.dmag;
-                }
-              else
-                {
-                  raw_bit = bv.dmag / bv.umag - 1;
-                }
-              const int expect_data_bit = bit & 1; /* expect 010101 */
-              const double q = expect_data_bit ? raw_bit : -raw_bit;
-              sync_quality += q * bv.count;
-              bit_count += bv.count;
-            }
-          if (bit_count)
-            {
-              sync_quality /= bit_count;
-              sync_quality = fabs (sync_quality);
-              //sync_quality = fabs (sync_finder.normalize_sync_quality (sync_quality));
-              //printf ("%d %f\n", offset, fabs (sync_quality));
-              if (sync_quality > best_score.quality)
-                {
-                  best_score.quality = sync_quality;
-                  best_score.speed = relative_speed * center;
-                }
+              best_score.quality = quality;
+              best_score.speed = relative_speed * center;
             }
         }
     }