libsaria: Implement a find_item() for lists

This function takes a function pointer argument that should return
"true" if the current item is the item we're looking for and "false"
otherwise.

Signed-off-by: Bryan Schumaker <bjschuma@gmail.com>

include/libsaria/list.h

@@ -20,6 +20,7 @@ namespace libsaria
 			ListItem();
 			ListItem(T, List<T> *);
 			~ListItem();
+			T &get_value();
 	};
 
 	template <class T>
@@ -38,6 +39,7 @@ namespace libsaria
 			unsigned int size();
 
 			void for_each_item(void (*)(T &, void *), void *);
+			ListItem<T> *find_item(bool (*)(T &, void *), void *);
 	};
 
 };

libsaria/library/library.cpp

@@ -66,6 +66,11 @@ static void sort_tracks(libsaria::Track &track, void *data)
 		sort->tracks.push_back(&track);
 }
 
+static bool check_trackid(libsaria::Track &track, void *data)
+{
+	return track.get_id() == *(unsigned int *)data;
+}
+
 void pop_path(libsaria::library::Path *path)
 {
 	list<libsaria::library::Path>::iterator it;
@@ -158,7 +163,7 @@ namespace libsaria
 	Track *library::lookup(unsigned int libid, unsigned int trackid)
 	{
 		list<Path>::iterator p_it;
-		list<Track>::iterator t_it;
+		ListItem<Track> *track;
 
 		for (p_it = path_list.begin(); p_it != path_list.end(); p_it++) {
 			if (p_it->id == libid)
@@ -167,13 +172,10 @@ namespace libsaria
 		if (p_it == path_list.end())
 			return NULL;
 
-		for (t_it = p_it->tracks.begin(); t_it != p_it->tracks.end(); t_it++) {
-			if (t_it->get_id() == trackid)
-				break;
-		}
-		if (t_it == p_it->tracks.end())
+		track = p_it->_tracks.find_item(check_trackid, &trackid);
+		if (track == NULL)
 			return NULL;
-		return &(*t_it);
+		return &track->get_value();
 	}
 
 	Playlist *library::get_playlist()

libsaria/list/list.cpp

@@ -73,13 +73,24 @@ namespace libsaria
 	void List<T>::for_each_item(void (*func)(T &, void *), void *data)
 	{
 		ListItem<T> *item = head.next;
-
 		while (item != &head) {
 			func(item->value, data);
 			item = item->next;
 		}
 	}
 
+	template <class T>
+	ListItem<T> *List<T>::find_item(bool (*func)(T &, void *), void *data)
+	{
+		ListItem<T> *item = head.next;
+		while (item != &head) {
+			if (func(item->value, data))
+				return item;
+			item = item->next;
+		}
+		return NULL;
+	}
+
 }
 
 #endif /* LIBSARIA_LIST_CPP */

libsaria/list/node.cpp

@@ -27,6 +27,12 @@ namespace libsaria
 	{
 	}
 
+	template <class T>
+	T &ListItem<T>::get_value()
+	{
+		return value;
+	}
+
 }
 
 #endif /* LIBSARIA_NODE_CPP */