Make the "Play last 500ms of selection" command always play to the end of the selection as it did in 2.1

Originally committed to SVN as r6171.

aegisub/src/audio_controller.cpp

@@ -429,6 +429,16 @@ void AudioController::PlayPrimaryRange()
 		playback_mode = PM_PrimaryRange;
 }
 
+void AudioController::PlayToEndOfPrimary(int64_t start_sample)
+{
+	if (!IsAudioOpen()) return;
+
+	player->Play(start_sample, GetPrimaryPlaybackRange().end() - start_sample);
+	playback_mode = PM_PrimaryRange;
+	playback_timer.Start(20);
+
+	AnnouncePlaybackPosition(start_sample);
+}
 
 void AudioController::PlayToEnd(int64_t start_sample)
 {

aegisub/src/audio_controller.h

@@ -306,6 +306,13 @@ public:
 	/// The playback end can not be changed in any other way.
 	void PlayPrimaryRange();
 
+	/// @brief Start or restart audio playback, playing from a point to the end of of the primary playback range
+	/// @param start_sample Index of the sample to start playback at
+	///
+	/// This behaves like PlayPrimaryRange, but the start point can differ from
+	/// the beginning of the primary range.
+	void PlayToEndOfPrimary(int64_t start_sample);
+
 	/// @brief Start or restart audio playback, playing from a point to the end of stream
 	/// @param start_sample Index of the sample to start playback at
 	///

aegisub/src/command/audio.cpp

@@ -290,11 +290,10 @@ struct audio_play_end : public validate_audio_open {
 	void operator()(agi::Context *c) {
 		c->videoController->Stop();
 		SampleRange times(c->audioController->GetPrimaryPlaybackRange());
-		c->audioController->PlayRange(SampleRange(
+		c->audioController->PlayToEndOfPrimary(
 			times.end() - std::min(
 				c->audioController->SamplesFromMilliseconds(500),
-				times.length()),
+				times.length()));
-			times.end()));
 	}
 };