add ::duration_is_explicit() to SMF

libs/evoral/SMF.cc

@@ -551,6 +551,16 @@ SMF::file_duration () const
 	return Temporal::Beats::ticks_at_rate (smf_get_length_pulses (_smf), ppqn());
 }
 
+bool
+SMF::duration_is_explicit () const
+{
+	if (!_smf) {
+		return false;
+	}
+
+	return smf_length_is_explicit (_smf);
+}
+
 double
 SMF::round_to_file_precision (double val) const
 {

libs/evoral/evoral/SMF.h

@@ -100,6 +100,7 @@ public:
 	int smf_format () const;
 
 	Temporal::Beats file_duration() const;
+	bool duration_is_explicit() const;
 
 	int num_channels () const { return _num_channels; }
 	typedef std::bitset<16> UsedChannels;