Clean up MidiSource::midi_read now that the signed type sframes_t is being used to pass positions around.

git-svn-id: svn://localhost/ardour2/branches/3.0@7726 d708f5d6-7413-0410-9779-e7cbd77b26cf

5 files changed, 15 insertions, 38 deletions

diff --git a/libs/ardour/ardour/midi_source.h b/libs/ardour/ardour/midi_source.h
index 5afcc20255..71c4eaca6d 100644
--- a/libs/ardour/ardour/midi_source.h
+++ b/libs/ardour/ardour/midi_source.h
@@ -56,15 +56,11 @@ class MidiSource : virtual public Source
 	 * \param source_start Start position of the SOURCE in this read context
 	 * \param start Start of range to be read
 	 * \param cnt Length of range to be read (in audio frames)
-	 * \param stamp_offset Offset to add to event times written to dst
-	 * \param negative_stamp_offset Offset to subtract from event times written to dst
 	 * \param tracker an optional pointer to MidiStateTracker object, for note on/off tracking
 	 */
 	virtual nframes_t midi_read (Evoral::EventSink<nframes_t>& dst,
 				     sframes_t source_start,
 				     sframes_t start, nframes_t cnt,
-				     sframes_t stamp_offset,
-				     sframes_t negative_stamp_offset,
 				     MidiStateTracker*,
 				     std::set<Evoral::Parameter> const &) const;
 
@@ -140,7 +136,6 @@ class MidiSource : virtual public Source
 	virtual nframes_t read_unlocked (Evoral::EventSink<nframes_t>& dst,
 					 sframes_t position,
 					 sframes_t start, nframes_t cnt,
-					 sframes_t stamp_offset, sframes_t negative_stamp_offset,
 					 MidiStateTracker* tracker) const = 0;
 
 	virtual nframes_t write_unlocked (MidiRingBuffer<nframes_t>& dst,
diff --git a/libs/ardour/ardour/smf_source.h b/libs/ardour/ardour/smf_source.h
index 956fb6c75f..ab62a2d211 100644
--- a/libs/ardour/ardour/smf_source.h
+++ b/libs/ardour/ardour/smf_source.h
@@ -77,8 +77,6 @@ public:
 				 sframes_t position,
 				 sframes_t start,
 				 nframes_t cnt,
-				 sframes_t stamp_offset,
-				 sframes_t negative_stamp_offset,
 				 MidiStateTracker* tracker) const;
 
 	nframes_t write_unlocked (MidiRingBuffer<nframes_t>& src,
diff --git a/libs/ardour/midi_region.cc b/libs/ardour/midi_region.cc
index df4d7f4b06..ae93a77445 100644
--- a/libs/ardour/midi_region.cc
+++ b/libs/ardour/midi_region.cc
@@ -124,7 +124,6 @@ MidiRegion::_read_at (const SourceList& /*srcs*/, Evoral::EventSink<nframes_t>&
 		      NoteMode mode, MidiStateTracker* tracker) const
 {
 	frameoffset_t internal_offset = 0;
-	frameoffset_t src_offset      = 0;
 	framecnt_t to_read         = 0;
 
 	/* precondition: caller has verified that we cover the desired section */
@@ -136,12 +135,12 @@ MidiRegion::_read_at (const SourceList& /*srcs*/, Evoral::EventSink<nframes_t>&
 	}
 
 	if (position < _position) {
+		/* we are starting the read from before the start of the region */
 		internal_offset = 0;
-		src_offset = _position - position;
-		dur -= src_offset;
+		dur -= _position - position;
 	} else {
+		/* we are starting the read from after the start of the region */
 		internal_offset = position - _position;
-		src_offset = 0;
 	}
 
 	if (internal_offset >= _length) {
@@ -157,31 +156,20 @@ MidiRegion::_read_at (const SourceList& /*srcs*/, Evoral::EventSink<nframes_t>&
 	boost::shared_ptr<MidiSource> src = midi_source(chan_n);
 	src->set_note_mode(mode);
 
-	framepos_t output_buffer_position = 0;
-	framepos_t negative_output_buffer_position = 0;
-	if (_position >= _start) {
-		// handle resizing of beginnings of regions correctly
-		output_buffer_position = _position - _start;
-	} else {
-		// the reverse of the above
-		negative_output_buffer_position = _start - _position;
-	}
-
 	/*cerr << "MR read @ " << position << " * " << to_read
 		<< " _position = " << _position
 	    << " _start = " << _start
 	    << " offset = " << output_buffer_position
-	    << " negoffset = " << negative_output_buffer_position
 	    << " intoffset = " << internal_offset
 	    << endl;*/
 
+	/* This call reads events from a source and writes them to `dst' timed in session frames */
+
 	if (src->midi_read (
 			dst, // destination buffer
-			_position - _start, // start position of the source in this read context
+			_position - _start, // start position of the source in session frames
 			_start + internal_offset, // where to start reading in the source
 			to_read, // read duration in frames
-			output_buffer_position, // the offset in the output buffer
-			negative_output_buffer_position, // amount to substract from note times
 			tracker,
 			_filtered_parameters
 		    ) != to_read) {
diff --git a/libs/ardour/midi_source.cc b/libs/ardour/midi_source.cc
index 97fb801a6c..4a0f20cbdb 100644
--- a/libs/ardour/midi_source.cc
+++ b/libs/ardour/midi_source.cc
@@ -199,7 +199,6 @@ MidiSource::invalidate ()
 nframes_t
 MidiSource::midi_read (Evoral::EventSink<nframes_t>& dst, sframes_t source_start,
                        sframes_t start, nframes_t cnt,
-                       sframes_t stamp_offset, sframes_t negative_stamp_offset,
                        MidiStateTracker* tracker,
 		       std::set<Evoral::Parameter> const & filtered) const
 {
@@ -229,8 +228,8 @@ MidiSource::midi_read (Evoral::EventSink<nframes_t>& dst, sframes_t source_start
 		for (; i != _model->end(); ++i) {
 			const sframes_t time_frames = converter.to(i->time());
 			if (time_frames < start + cnt) {
-				dst.write(time_frames + stamp_offset - negative_stamp_offset,
-                                          i->event_type(), i->size(), i->buffer());
+				/* convert event times to session frames by adding on the source start position in session frames */
+				dst.write (time_frames + source_start, i->event_type(), i->size(), i->buffer());
 
 				if (tracker) {
 					Evoral::MIDIEvent<Evoral::MusicalTime>& ev (*(Evoral::MIDIEvent<Evoral::MusicalTime>*) (&(*i)));
@@ -248,7 +247,7 @@ MidiSource::midi_read (Evoral::EventSink<nframes_t>& dst, sframes_t source_start
 		}
 		return cnt;
 	} else {
-		return read_unlocked (dst, source_start, start, cnt, stamp_offset, negative_stamp_offset, tracker);
+		return read_unlocked (dst, source_start, start, cnt, tracker);
 	}
 }
 
diff --git a/libs/ardour/smf_source.cc b/libs/ardour/smf_source.cc
index 5ce87fe93e..d03489e6e8 100644
--- a/libs/ardour/smf_source.cc
+++ b/libs/ardour/smf_source.cc
@@ -105,9 +105,8 @@ SMFSource::~SMFSource ()
 
 /** All stamps in audio frames */
 nframes_t
-SMFSource::read_unlocked (Evoral::EventSink<nframes_t>& destination, sframes_t source_start,
+SMFSource::read_unlocked (Evoral::EventSink<nframes_t>& destination, sframes_t const source_start,
 			  sframes_t start, nframes_t duration,
-			  sframes_t stamp_offset, sframes_t negative_stamp_offset,
 			  MidiStateTracker* tracker) const
 {
 	int      ret  = 0;
@@ -171,16 +170,14 @@ SMFSource::read_unlocked (Evoral::EventSink<nframes_t>& destination, sframes_t s
 								  ev_delta_t, time, ev_buffer[0], ev_type));
 
 		assert(time >= start_ticks);
-		const sframes_t ev_frame_time = converter.to(time / (double)ppqn()) + stamp_offset;
 
-#if 0
-		cerr << " frames = " << ev_frame_time
-		     << " w/offset = " << ev_frame_time - negative_stamp_offset
-		     << endl;
-#endif
+		/* Note that we add on the source start time (in session frames) here so that ev_frame_time
+		   is in session frames.
+		*/
+		const sframes_t ev_frame_time = converter.to(time / (double)ppqn()) + source_start;
 
 		if (ev_frame_time < start + duration) {
-			destination.write(ev_frame_time - negative_stamp_offset, ev_type, ev_size, ev_buffer);
+			destination.write (ev_frame_time, ev_type, ev_size, ev_buffer);
 
 			if (tracker) {
 				if (ev_buffer[0] & MIDI_CMD_NOTE_ON) {