Use ThreadPool for refining sync results (performance).

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

src/syncfinder.cc

@@ -280,8 +280,8 @@ SyncFinder::sync_select_n_best (vector<Score>& sync_scores, size_t n)
 void
 SyncFinder::search_refine (const WavData& wav_data, Mode mode, KeyResult& key_result, const vector<vector<FrameBit>>& sync_bits)
 {
-  vector<float> fft_db;
-  vector<char>  have_frames;
+  ThreadPool    thread_pool;
+  std::mutex    result_mutex;
   vector<Score> result_scores;
   BitPosGen     bit_pos_gen (key_result.key);
 
@@ -300,6 +300,11 @@ SyncFinder::search_refine (const WavData& wav_data, Mode mode, KeyResult& key_re
 
   for (const auto& score : key_result.sync_scores)
     {
+      thread_pool.add_job ([this, score, total_frame_count,
+                            &wav_data, &want_frames, &sync_bits, &result_scores, &result_mutex] ()
+        {
+          vector<float> fft_db;
+          vector<char>  have_frames;
           //printf ("%zd %s %f", score.index, find_closest_sync (score.index).c_str(), score.quality);
 
           // refine match
@@ -326,8 +331,13 @@ SyncFinder::search_refine (const WavData& wav_data, Mode mode, KeyResult& key_re
             }
           //printf (" => refined: %zd %s %f\n", best_index, find_closest_sync (best_index).c_str(), best_quality);
           if (best_quality > Params::sync_threshold2)
+            {
+              std::lock_guard<std::mutex> lg (result_mutex);
               result_scores.push_back (Score { best_index, best_quality, best_block_type });
             }
+        });
+    }
+  thread_pool.wait_all();
   key_result.sync_scores = result_scores;
 }