Cleanup clip decoder padding code.

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

src/wmget.cc

@@ -652,6 +652,8 @@ public:
 
 class ClipDecoder
 {
+  const int frames_per_block = 0;
+
   void
   run_padded (const WavData& l_wav_data, ResultSet& result_set, double time_offset_sec)
   {
@@ -695,13 +697,47 @@ class ClipDecoder
           }
       }
   }
+  enum class Pos { START, END };
+  void
+  run_block (const WavData& wav_data, ResultSet& result_set, int pad_frames_start, int pad_frames_end, Pos pos)
+  {
+    double time_offset;
+    vector<float> ext_samples;
+    const size_t n = (frames_per_block + 5) * Params::frame_size * wav_data.n_channels();
+    if (pos == Pos::START)
+      {
+        ext_samples = wav_data.samples();
+        if (ext_samples.size() > n)
+          ext_samples.resize (n);
+
+        time_offset = 0;
+      }
+    else // (pos == Pos::END)
+      {
+        auto s = wav_data.samples();
+        if (n > s.size())
+          return;
+        ext_samples.assign (s.end() - n, s.end());
+
+        time_offset = double (s.size() - n) / wav_data.sample_rate() / wav_data.n_channels();
+      }
+    // printf ("%d: %f..%f\n", int (pos), time_offset, time_offset + double (ext_samples.size()) / wav_data.sample_rate() / wav_data.n_channels());
+
+    ext_samples.insert (ext_samples.begin(), pad_frames_start * Params::frame_size * wav_data.n_channels(), 0);
+    ext_samples.insert (ext_samples.end(),   pad_frames_end   * Params::frame_size * wav_data.n_channels(), 0);
+
+    WavData l_wav_data (ext_samples, wav_data.n_channels(), wav_data.sample_rate(), wav_data.bit_depth());
+    run_padded (l_wav_data, result_set, time_offset);
+   }
 public:
+  ClipDecoder() :
+    frames_per_block (mark_sync_frame_count() + mark_data_frame_count())
+  {
+  }
   void
   run (const WavData& wav_data, ResultSet& result_set)
   {
-    // L-blocks
     const int wav_frames = wav_data.n_values() / (Params::frame_size * wav_data.n_channels());
-    const int frames_per_block = mark_sync_frame_count() + mark_data_frame_count();
     if (wav_frames < frames_per_block * 3.1) /* clip decoder is only used for small wavs */
       {
         // clip decoder padding at start:
@@ -710,41 +746,8 @@ public:
         //  - 5 extra frames as safety
         const int pad_frames_start = max (frames_per_block, frames_per_block * 2 - wav_frames) + 5;
 
-        // clip decoder padding at end:
-        //  - one data block + 5 extra frames as safety
-        // for short clips, the sync pattern of the data block repeats after one block length
-        const int pad_frames_end = frames_per_block + 5;
-
-        // truncate to one data block
-        const int max_frames = (frames_per_block + 5) * Params::frame_size * wav_data.n_channels();
-        auto ext_samples = wav_data.samples();
-        if (ext_samples.size() > max_frames)
-          ext_samples.resize (max_frames);
-
-        printf ("START: %f..%f\n", 0.0, double (ext_samples.size()) / wav_data.sample_rate() / wav_data.n_channels());
-
-        ext_samples.insert (ext_samples.begin(), pad_frames_start * Params::frame_size * wav_data.n_channels(), 0);
-        ext_samples.insert (ext_samples.end(),   pad_frames_end   * Params::frame_size * wav_data.n_channels(), 0);
-
-        WavData l_wav_data (ext_samples, wav_data.n_channels(), wav_data.sample_rate(), wav_data.bit_depth());
-
-        run_padded (l_wav_data, result_set, 0);
-
-        if (wav_data.samples().size() > max_frames)
-          {
-            int pad_frames_start = frames_per_block + 5;
-            int pad_frames_end   = frames_per_block + 5;
-            size_t n = (frames_per_block + 5) * Params::frame_size * wav_data.n_channels();
-            auto s = wav_data.samples();
-            ext_samples.assign (s.end() - n, s.end());
-            printf ("END: %f..%f\n", double (s.size() - n) / wav_data.sample_rate() / wav_data.n_channels(),
-                                     double (s.size()) / wav_data.sample_rate() / wav_data.n_channels());
-            ext_samples.insert (ext_samples.begin(), pad_frames_start * Params::frame_size * wav_data.n_channels(), 0);
-            ext_samples.insert (ext_samples.end(),   pad_frames_end   * Params::frame_size * wav_data.n_channels(), 0);
-
-            WavData l_wav_data (ext_samples, wav_data.n_channels(), wav_data.sample_rate(), wav_data.bit_depth());
-            run_padded (l_wav_data, result_set, double (s.size() - n) / wav_data.sample_rate() / wav_data.n_channels());
-          }
+        run_block (wav_data, result_set, pad_frames_start, frames_per_block + 5, Pos::START);
+        run_block (wav_data, result_set, frames_per_block + 5, frames_per_block + 5, Pos::END);
       }
   }
 };