fix up a few zero-boundary condition errors in TempoMap

git-svn-id: svn://localhost/ardour2/branches/3.0@11196 d708f5d6-7413-0410-9779-e7cbd77b26cf

diff --git a/libs/ardour/tempo.cc b/libs/ardour/tempo.cc
index c39b8d07579dca3207b854a269ea8d5540961f52..d1458dba6dd66ffb41a8604aa407f894e2d35a1b 100644 (file)
--- a/libs/ardour/tempo.cc
+++ b/libs/ardour/tempo.cc
@@ -1106,6 +1106,15 @@ TempoMap::bbt_time (framepos_t frame, BBT_Time& bbt)
        require_map_to (frame);
 
        Glib::RWLock::ReaderLock lm (lock);
+
+       if (frame < 0) {
+               bbt.bars = 1;
+               bbt.beats = 1;
+               bbt.ticks = 0;
+               warning << string_compose (_("tempo map asked for BBT time at frame %1\n"), frame) << endmsg;
+               return;
+       }
+
        return bbt_time (frame, bbt, bbt_before_or_at (frame));
 }
 
@@ -1144,6 +1153,15 @@ TempoMap::bbt_time (framepos_t frame, BBT_Time& bbt, const BBTPointList::const_i
 framepos_t
 TempoMap::frame_time (const BBT_Time& bbt)
 {
+       if (bbt.bars < 1) {
+               warning << string_compose (_("tempo map asked for frame time at bar < 1  (%1)\n"), bbt) << endmsg;
+               return 0;
+       }
+       
+       if (bbt.beats < 1) {
+               throw std::logic_error ("beats are counted from one");
+       }
+
        require_map_to (bbt);
 
        Glib::RWLock::ReaderLock lm (lock);
@@ -2193,11 +2211,16 @@ TempoMap::bbt_before_or_at (framepos_t pos)
 
        BBTPointList::const_iterator i;
 
+       if (pos < 0) {
+               /* not really correct, but we should catch pos < 0 at a higher
+                  level 
+               */
+               return _map.begin();
+       }
+
        i = lower_bound (_map.begin(), _map.end(), pos);
        assert (i != _map.end());
        if ((*i).frame > pos) {
-               cerr << "lower bound was found at " << (*i).frame << " for " << pos;
-               dump (cerr);
                assert (i != _map.begin());
                --i;
        }