Add lua methods to control range locations

Method Session:locations():range_starts_at(pos, slop, incl)
to search range by start point with some inaccuracy delta.
Similar to mark_at(pos, slop)

Method Session:locations():add_range(start, end)
to create new range and get it for later changes.

libs/ardour/ardour/location.h

@@ -189,6 +189,16 @@ public:
 	LocationList list () { return locations; }
 
 	void add (Location *, bool make_current = false);
+
+	/** Add new range to the collection
+	 *
+	 * @param start start position
+	 * @param end end position
+	 *
+	 * @return New location object
+	 */
+	Location* add_range (samplepos_t start, samplepos_t end);
+
 	void remove (Location *);
 	void clear ();
 	void clear_markers ();
@@ -218,6 +228,16 @@ public:
 
 	void marks_either_side (samplepos_t const, samplepos_t &, samplepos_t &) const;
 
+	/** Return range with closest start pos to the where argument
+	 *
+	 * @param pos point to compare with start pos
+	 * @param slop area around point to search for start pos
+	 * @param incl (optional) look only for ranges that includes 'where' point
+	 *
+	 * @return Location object or nil
+	 */
+	Location* range_starts_at(samplepos_t pos, samplecnt_t slop = 0, bool incl = false) const;
+
 	void find_all_between (samplepos_t start, samplepos_t, LocationList&, Location::Flags);
 
 	PBD::Signal1<void,Location*> current_changed;

libs/ardour/location.cc

@@ -1017,6 +1017,18 @@ Locations::add (Location *loc, bool make_current)
 	}
 }
 
+Location*
+Locations::add_range(samplepos_t start, samplepos_t end)
+{
+	string name;
+	next_available_name(name, _("range"));
+
+	Location* loc = new Location(_session, start, end, name, Location::IsRangeMarker);
+	add(loc, false);
+
+	return loc;
+}
+
 void
 Locations::remove (Location *loc)
 {
@@ -1484,3 +1496,42 @@ Locations::find_all_between (samplepos_t start, samplepos_t end, LocationList& l
 		}
 	}
 }
+
+Location *
+Locations::range_starts_at(samplepos_t pos, samplecnt_t slop, bool incl) const
+{
+	Glib::Threads::Mutex::Lock lm(lock);
+	Location *closest = 0;
+	sampleoffset_t mindelta = max_samplepos;
+	sampleoffset_t delta;
+
+	for (LocationList::const_iterator i = locations.begin(); i != locations.end(); ++i)
+	{
+
+		if ((*i)->is_range_marker())
+		{
+			if (incl && (pos < (*i)->start() || pos > (*i)->end())) {
+				continue;
+			}
+
+			delta = std::abs(pos - (*i)->start());
+
+			if (delta == 0)
+			{
+				return *i;
+			}
+
+			if (delta > slop) {
+				continue;
+			}
+
+			if (delta < mindelta)
+			{
+				closest = *i;
+				mindelta = delta;
+			}
+		}
+	}
+
+	return closest;
+}

libs/ardour/luabindings.cc

@@ -886,6 +886,8 @@ LuaBindings::common (lua_State* L)
 		.addFunction ("first_mark_before", &Locations::first_mark_before)
 		.addFunction ("first_mark_at", &Locations::mark_at)
 		.addFunction ("mark_at", &Locations::mark_at)
+		.addFunction ("range_starts_at", &Locations::range_starts_at)
+		.addFunction ("add_range", &Locations::add_range)
 		.addFunction ("remove", &Locations::remove)
 		.addRefFunction ("marks_either_side", &Locations::marks_either_side)
 		.addRefFunction ("find_all_between", &Locations::find_all_between)