Introduce SpeedSearch class.

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

src/wmspeed.cc

@@ -367,8 +367,36 @@ score_average_best (const vector<SpeedSync::Score>& scores)
   return best_speed;
 }
 
-static vector<SpeedSync::Score>
-run_search (ThreadPool& thread_pool, vector<std::unique_ptr<SpeedSync>>& speed_sync, const SpeedScanParams& scan_params, const WavData& in_data, double clip_location, const vector<double>& speeds)
+class SpeedSearch
+{
+  ThreadPool thread_pool;
+  vector<std::unique_ptr<SpeedSync>> speed_sync;
+  const WavData& in_data;
+  double clip_location;
+
+  SpeedSync *
+  find_closest_speed_sync (double speed)
+  {
+    auto it = std::min_element (speed_sync.begin(), speed_sync.end(), [&](auto& x, auto& y)
+      {
+        return fabs (x->center_speed() - speed) < fabs (y->center_speed() - speed);
+      });
+    return (*it).get();
+  }
+
+public:
+  SpeedSearch (const WavData& in_data, double clip_location) :
+    in_data (in_data),
+    clip_location (clip_location)
+  {
+  }
+
+  vector<SpeedSync::Score> run_search (const SpeedScanParams& scan_params, const vector<double>& speeds);
+  vector<SpeedSync::Score> refine_search (const SpeedScanParams& scan_params, double speed);
+};
+
+vector<SpeedSync::Score>
+SpeedSearch::run_search (const SpeedScanParams& scan_params, const vector<double>& speeds)
 {
   /* speed is between 0.8 and 1.25, so we use a clip seconds factor of 1.3 to provide enough samples */
   WavData in_clip = get_speed_clip (clip_location, in_data, scan_params.seconds * 1.3);
@@ -403,6 +431,24 @@ run_search (ThreadPool& thread_pool, vector<std::unique_ptr<SpeedSync>>& speed_s
   return scores;
 }
 
+vector<SpeedSync::Score>
+SpeedSearch::refine_search (const SpeedScanParams& scan_params, double speed)
+{
+  SpeedSync *center_speed_sync = find_closest_speed_sync (speed);
+
+  auto t0 = get_time();
+
+  center_speed_sync->start_search_jobs (thread_pool, scan_params, speed);
+  thread_pool.wait_all();
+
+  auto t1 = get_time();
+
+  printf ("detect_speed %.3f\n", t1 - t0);
+
+  return center_speed_sync->get_scores();
+}
+
+
 static void
 select_n_best_scores (vector<SpeedSync::Score>& scores, size_t n)
 {
@@ -438,16 +484,6 @@ select_n_best_scores (vector<SpeedSync::Score>& scores, size_t n)
   scores = lmax_scores;
 }
 
-static SpeedSync *
-find_closest_speed_sync (const vector<std::unique_ptr<SpeedSync>>& speed_sync, double speed)
-{
-  auto it = std::min_element (speed_sync.begin(), speed_sync.end(), [&](auto& x, auto& y)
-    {
-      return fabs (x->center_speed() - speed) < fabs (y->center_speed() - speed);
-    });
-  return (*it).get();
-}
-
 static vector<double>
 get_clip_locations (const WavData& in_data, int n)
 {
@@ -534,9 +570,8 @@ detect_speed (const WavData& in_data, bool print_results)
   const int    clip_candidates = 5;
   const double clip_location = get_best_clip_location (in_data, scan1.seconds, clip_candidates);
 
-  ThreadPool thread_pool;
-  vector<std::unique_ptr<SpeedSync>> speed_sync;
   vector<SpeedSync::Score> scores;
+  SpeedSearch search_context (in_data, clip_location);
 
   /* search using grid */
   {
@@ -547,43 +582,32 @@ detect_speed (const WavData& in_data, bool print_results)
         speeds.push_back (pow (scan1.step, c * (scan1.n_steps * 2 + 1)));
       }
 
-    scores = run_search (thread_pool, speed_sync, scan1, in_data, clip_location, speeds);
+    scores = search_context.run_search (scan1, speeds);
   }
 
   if (Params::detect_speed_patient)
     {
       select_n_best_scores (scores, 1);
 
-      scores = run_search (thread_pool, speed_sync, scan3, in_data, clip_location, { scores[0].speed });
-
-      return score_average_best (scores);
+      scores = search_context.run_search (scan3, { scores[0].speed });
     }
+  else
+    {
+      /* search 5 best matches */
+      select_n_best_scores (scores, 5);
 
-  /* search 5 best matches */
-  select_n_best_scores (scores, 5);
-  {
-    vector<double> speeds;
-    for (auto score : scores)
-      speeds.push_back (score.speed);
-
-    scores = run_search (thread_pool, speed_sync, scan2, in_data, clip_location, speeds);
-  }
-
-  select_n_best_scores (scores, 1);
-
-  /* refine best match */
-  SpeedSync *center_speed_sync = find_closest_speed_sync (speed_sync, scores[0].speed);
-
-  auto t4 = get_time();
-
-  center_speed_sync->start_search_jobs (thread_pool, scan3, scores[0].speed);
-  thread_pool.wait_all();
+      vector<double> speeds;
+      for (auto score : scores)
+        speeds.push_back (score.speed);
 
-  auto t5 = get_time();
+      scores = search_context.run_search (scan2, speeds);
 
-  printf ("detect_speed %.3f\n", t5 - t4);
+      /* refine best match */
+      select_n_best_scores (scores, 1);
 
-  return score_average_best (center_speed_sync->get_scores());
+      scores = search_context.refine_search (scan3, scores[0].speed);
+    }
+  return score_average_best (scores);
 
 #if 0
   if (print_results)