libsaria: Add filtering to the new index

Otherwise it's useless.  I search all three indexes and use the union of
those results to determine what is visible.

include/libsaria/index.h

@@ -10,6 +10,10 @@ namespace libsaria
 	{
 
 		void add_track(libsaria::Track &);
+		void filter(string &);
+		bool is_visible(sid_t &);
+		bool is_filtered();
+		unsigned int size();
 		void print_stats();
 
 	}; /* Namespace: index */

libsaria/index/filter.cpp

@@ -0,0 +1,115 @@
+
+#include <libsaria/index.h>
+#include <libsaria/format.h>
+#include <libsaria/callback.h>
+#include "index.h"
+
+static set<sid_t> results;
+static bool filtered = false;
+
+/*
+ * Thanks to: http://stackoverflow.com/questions/1773526/in-place-c-set-intersection
+ * for the set intersection algorithm!
+ */
+static void inplace_intersect(set<sid_t> *ids)
+{
+	set<sid_t>::iterator it1 = results.begin();
+	set<sid_t>::iterator it2 = ids->begin();
+
+	while ( (it1 != results.end()) && (it2 != ids->end()) ) {
+		if (*it1 < *it2)
+			results.erase(it1++);
+		else if (*it2 < *it1)
+			it2++;
+		else { /* *it1 == *it2 */
+			it1++;
+			it2++;
+		}
+	}
+
+	/* Remove everything in results that wasn't in inodes */
+	results.erase(it1, results.end());
+
+}
+
+static inline void search_index(string &term,
+				map<string, set<sid_t> > *index,
+				set<ino_t> *found)
+{
+	map<string, set<sid_t> >::iterator it;
+	it = index->find(term);
+	if (it != index->end())
+		found->insert(it->second.begin(), it->second.end());
+}
+
+static inline void search_indexes(string &term, set<ino_t> *found)
+{
+	search_index(term, &artist_index, found);
+	search_index(term, &album_index,  found);
+	search_index(term, &title_index,  found);
+}
+
+static void do_filter(list<string> *terms)
+{
+	set<ino_t> found;
+	list<string>::iterator it;
+
+	for (it = terms->begin(); it != terms->end(); it++) {
+		found.clear();
+		search_indexes(*it, &found);
+		/*
+		 * Key not found means we don't need to filter anymore
+		 * just clear the results set and return.
+		 */
+		if (found.size() == 0) {
+			results.clear();
+			return;
+		}
+		/*
+		 * This is the first result, so the result set is empty.
+		 * Taking an intersection will always give us an empty set.
+		 */
+		if (it == terms->begin())
+			results = found;
+		else
+			inplace_intersect(&found);
+	}
+}
+
+namespace libsaria
+{
+
+	void index::filter(string &search)
+	{
+		list<string> *terms = format_text(search);
+		results.clear();
+
+		if (terms->size() == 0)
+			filtered = false;
+		else {
+			do_filter(terms);
+			filtered = true;
+		}
+		trigger_callback(REFILTER);
+	}
+
+	bool index::is_visible(sid_t &songid)
+	{
+		set<sid_t>::iterator it;
+
+		if (filtered == false)
+			return true;
+		it = results.find(songid);
+		return it != results.end();
+	}
+
+	bool index::is_filtered()
+	{
+		return filtered;
+	}
+
+	unsigned int index::size()
+	{
+		return results.size();
+	}
+};

libsaria/index/index.cpp

@@ -2,6 +2,7 @@
 #include <libsaria/track.h>
 #include <libsaria/index.h>
 #include <libsaria/format.h>
+#include "index.h"
 
 #include <map>
 #include <set>

libsaria/index/index.h

@@ -0,0 +1,13 @@
+#ifndef LIBSARIA_INDEX_INTERNAL_H
+#define LIBSARIA_INDEX_INTERNAL_H
+
+#include <map>
+#include <set>
+#include <string>
+using namespace std;
+
+extern map<string, set<sid_t> > artist_index;
+extern map<string, set<sid_t> > album_index;
+extern map<string, set<sid_t> > title_index;
+
+#endif /* LIBSARIA_INDEX_INTERNAL_H */

libsaria/library/list.cpp

@@ -6,6 +6,7 @@ using namespace std;
 
 #include <libsaria/audio.h>
 #include <libsaria/prefs.h>
+#include <libsaria/index.h>
 #include <libsaria/print.h>
 #include "library.h"
 
@@ -91,7 +92,7 @@ static void print_cur_track()
 static void random_next()
 {
 	cur_track = play_list.begin();
-	if (libsaria::library::is_filtered()) {
+	if (libsaria::index::is_filtered()) {
 		println("Picking random track from index");
 		sid_t inode = libsaria::library::index_rand();
 		libsaria::library::play_id(inode);
@@ -112,7 +113,7 @@ static void sequential_next()
 		if (cur_track == play_list.end())
 			cur_track = play_list.begin();
 		inode = (*cur_track)->get_songid();
-	} while (!libsaria::library::is_visible(inode));
+	} while (!libsaria::index::is_visible(inode));
 }
 
 static void pick_next()
@@ -197,8 +198,8 @@ namespace libsaria
 
 	unsigned int library::size()
 	{
-		if (is_filtered() == true)
-			return filter_size();
+		if (index::is_filtered() == true)
+			return index::size();
 		return play_list.size();
 	}