Refactor sync search: move helpers to SyncFinder class.

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

src/audiowmark.cc

@@ -818,7 +818,7 @@ public:
       get_up_down (i, up[i], down[i]);
   }
   double
-  sync_decode (const WavData& wav_data, vector<vector<complex<float>>>& fft_out, vector<vector<complex<float>>>& fft_orig_out)
+  sync_decode (const WavData& wav_data, const vector<vector<complex<float>>>& fft_out, const vector<vector<complex<float>>>& fft_orig_out)
   {
     // FIXME: is copypasted
     const int frame_count = mark_sync_frame_count();
@@ -865,49 +865,9 @@ public:
     sync_quality = normalize_sync_quality (sync_quality);
     return sync_quality;
   }
-};
-
-vector<vector<complex<float>>>
-sync_fft (const WavData& wav_data, size_t index, size_t count)
-{
-  if (wav_data.n_values() < (index + count * Params::frame_size) * wav_data.n_channels())
-    return {};
-
-  vector<float> part_signal;
-  for (size_t i = 0; i < count * Params::frame_size; i++)
+  void
+  search (const WavData& wav_data)
   {
-      for (int ch = 0; ch < wav_data.n_channels(); ch++)
-        part_signal.push_back (wav_data.samples()[(index + i) * wav_data.n_channels() + ch]);
-    }
-  WavData wav_part (part_signal, wav_data.n_channels(), wav_data.mix_freq(), wav_data.bit_depth());
-  return compute_frame_ffts (wav_part);
-}
-
-const char*
-find_closest_sync (size_t index)
-{
-  int best_error = 0xffff;
-  int best = 0;
-
-  for (int i = 0; i < 100; i++)
-    {
-      int error = abs (int (index) - int (i * Params::sync_bits * Params::sync_frames_per_bit * Params::frame_size));
-      if (error < best_error)
-        {
-          best = i;
-          best_error = error;
-        }
-    }
-  static char buffer[1024]; // this code is for debugging only, so this should be ok
-  sprintf (buffer, "n:%d offset:%d", best, int (index) - int (best * Params::sync_bits * Params::sync_frames_per_bit * Params::frame_size));
-  return buffer;
-}
-
-int
-decode_and_report (const WavData& wav_data, const string& orig_pattern, vector<vector<complex<float>>>& fft_out, vector<vector<complex<float>>>& fft_orig_out)
-{
-  SyncFinder sync_finder;
-
     struct SyncScore {
       size_t index;
       double quality;
@@ -928,7 +888,7 @@ decode_and_report (const WavData& wav_data, const string& orig_pattern, vector<v
               {
                 vector<vector<complex<float>>> fft_out_range = get_frame_range (wav_data, fft_sync_shift_out[sync_shift / 128], start_frame, mark_sync_frame_count());
 
-              double quality = sync_finder.sync_decode (wav_data, fft_out_range, /* FIXME: non-blind */ fft_orig_out);
+                double quality = sync_decode (wav_data, fft_out_range, /* FIXME: non-blind */ {});
                 // printf ("%zd %f\n", sync_index, quality);
                 sync_scores.emplace_back (SyncScore { sync_index, quality });
               }
@@ -964,7 +924,7 @@ decode_and_report (const WavData& wav_data, const string& orig_pattern, vector<v
                     vector<vector<complex<float>>> fft_out_range = sync_fft (wav_data, fine_index, mark_sync_frame_count());
                     if (fft_out_range.size())
                       {
-                      double q = sync_finder.sync_decode (wav_data, fft_out_range, fft_orig_out);
+                        double q = sync_decode (wav_data, fft_out_range, {});
 
                         if (q > best_quality)
                           {
@@ -977,6 +937,50 @@ decode_and_report (const WavData& wav_data, const string& orig_pattern, vector<v
               }
           }
       }
+  }
+  vector<vector<complex<float>>>
+  sync_fft (const WavData& wav_data, size_t index, size_t count)
+  {
+    if (wav_data.n_values() < (index + count * Params::frame_size) * wav_data.n_channels())
+      return {};
+
+    vector<float> part_signal;
+    for (size_t i = 0; i < count * Params::frame_size; i++)
+      {
+        for (int ch = 0; ch < wav_data.n_channels(); ch++)
+          part_signal.push_back (wav_data.samples()[(index + i) * wav_data.n_channels() + ch]);
+      }
+    WavData wav_part (part_signal, wav_data.n_channels(), wav_data.mix_freq(), wav_data.bit_depth());
+    return compute_frame_ffts (wav_part);
+  }
+
+  const char*
+  find_closest_sync (size_t index)
+  {
+    int best_error = 0xffff;
+    int best = 0;
+
+    for (int i = 0; i < 100; i++)
+      {
+        int error = abs (int (index) - int (i * Params::sync_bits * Params::sync_frames_per_bit * Params::frame_size));
+        if (error < best_error)
+          {
+            best = i;
+            best_error = error;
+          }
+      }
+    static char buffer[1024]; // this code is for debugging only, so this should be ok
+    sprintf (buffer, "n:%d offset:%d", best, int (index) - int (best * Params::sync_bits * Params::sync_frames_per_bit * Params::frame_size));
+    return buffer;
+  }
+};
+
+int
+decode_and_report (const WavData& wav_data, const string& orig_pattern, vector<vector<complex<float>>>& fft_out, vector<vector<complex<float>>>& fft_orig_out)
+{
+  SyncFinder sync_finder;
+
+  sync_finder.search (wav_data);
   return 0;
 
   vector<float> soft_bit_vec;