From 192b2fd839f6332cbc72bf5507522f3361114dbc Mon Sep 17 00:00:00 2001
From: Paul Davis <paul@linuxaudiosystems.com>
Date: Mon, 30 May 2022 21:14:33 -0600
Subject: [PATCH] temporal: fixes for TempoMap::move_meter()

---
 libs/temporal/tempo.cc         | 33 +++++++++++++++++++++++++--------
 libs/temporal/temporal/tempo.h |  2 +-
 2 files changed, 26 insertions(+), 9 deletions(-)

diff --git a/libs/temporal/tempo.cc b/libs/temporal/tempo.cc
index ceaae80ba6..5d7abae388 100644
--- a/libs/temporal/tempo.cc
+++ b/libs/temporal/tempo.cc
@@ -1251,7 +1251,7 @@ TempoMap::reset_starting_at (superclock_t sc)
 }
 
 bool
-TempoMap::move_meter (MeterPoint const & mp, timepos_t const & when, bool push)
+TempoMap::move_meter (MeterPoint const & mp, timepos_t const & when, bool earlier, bool push)
 {
 	assert (!_tempos.empty());
 	assert (!_meters.empty());
@@ -1268,10 +1268,10 @@ TempoMap::move_meter (MeterPoint const & mp, timepos_t const & when, bool push)
 
 	beats = when.beats ();
 
-	if (beats > mp.beats ()) {
-		round_up = true;
-	} else {
+	if (earlier) {
 		round_up = false;
+	} else {
+		round_up = true;
 	}
 
 	/* Do not allow moving a meter marker to the same position as
@@ -1284,21 +1284,38 @@ TempoMap::move_meter (MeterPoint const & mp, timepos_t const & when, bool push)
 	/* meter changes must be on bar */
 	for (t = _tempos.begin(), prev_t = _tempos.end(); t != _tempos.end() && t->beats() < beats; ++t) { prev_t = t; }
 	for (m = _meters.begin(), prev_m = _meters.end(); m != _meters.end() && m->beats() < beats && *m != mp; ++m) { prev_m = m; }
-	assert (prev_m != _meters.end());
-	if (prev_t == _tempos.end()) { prev_t = _tempos.begin(); }
+
+	if (prev_m == _meters.end()) {
+		return false;
+	}
+
+	if (prev_t == _tempos.end()) {
+		prev_t = _tempos.begin();
+	}
+
 	TempoMetric metric (*prev_t, *prev_m);
 	bbt = metric.bbt_at (beats);
+
 	if (round_up) {
 		bbt = metric.meter().round_up_to_bar (bbt);
 	} else {
 		bbt = metric.meter().round_down_to_bar (bbt);
 	}
+
 	for (t = _tempos.begin(), prev_t = _tempos.end(); t != _tempos.end() && t->bbt() < bbt; ++t) { prev_t = t; }
 	for (m = _meters.begin(), prev_m = _meters.end(); m != _meters.end() && m->bbt() < bbt && *m != mp; ++m) { prev_m = m; }
-	assert (prev_m != _meters.end());
-	if (prev_t == _tempos.end()) { prev_t = _tempos.begin(); }
+
+	if (prev_m == _meters.end()) {
+		return false;
+	}
+
+	if (prev_t == _tempos.end()) {
+		prev_t = _tempos.begin();
+	}
+
 	metric = TempoMetric (*prev_t, *prev_m);
 	beats = metric.quarters_at (bbt);
+
 	for (m = _meters.begin(), prev_m = _meters.end(); m != _meters.end(); ++m) {
 		if (&*m != &mp) {
 			if (m->beats() == beats) {
diff --git a/libs/temporal/temporal/tempo.h b/libs/temporal/temporal/tempo.h
index b7fcb2d796..b1610a9a47 100644
--- a/libs/temporal/temporal/tempo.h
+++ b/libs/temporal/temporal/tempo.h
@@ -719,7 +719,7 @@ class /*LIBTEMPORAL_API*/ TempoMap : public PBD::StatefulDestructible
 
 	/* these are a convenience method that just wrap some odd semantics */
 	LIBTEMPORAL_API bool move_tempo (TempoPoint const & point, timepos_t const & destination, bool push = false);
-	LIBTEMPORAL_API bool move_meter (MeterPoint const & point, timepos_t const & destination, bool push = false);
+	LIBTEMPORAL_API bool move_meter (MeterPoint const & point, timepos_t const & destination, bool earlier, bool push = false);
 
 	LIBTEMPORAL_API int set_state (XMLNode const&, int version);