libsaria: Began new index

Right now I just add songs to it and cache substrings for each word.  I
also print out stats during libsaria shutdown.

include/libsaria/index.h

@@ -0,0 +1,18 @@
+#ifndef LIBSARIA_INDEX_H
+#define LIBSARIA_INDEX_H
+
+#include <libsaria/track.h>
+
+namespace libsaria
+{
+
+	namespace index
+	{
+
+		void add_track(libsaria::Track &);
+		void print_stats();
+
+	}; /* Namespace: index */
+
+}; /* Namespace: libsaria */
+#endif /* LIBSARIA_INDEX_H */

libsaria/index/index.cpp

@@ -0,0 +1,100 @@
+
+#include <libsaria/track.h>
+#include <libsaria/index.h>
+#include <libsaria/format.h>
+
+#include <map>
+#include <set>
+#include <string>
+using namespace std;
+
+map<string, set<sid_t> > artist_index;
+map<string, set<sid_t> > album_index;
+map<string, set<sid_t> > title_index;
+
+static map<string, set<string> > substr_cache;
+unsigned int hits;
+unsigned int misses;
+
+static set<string> *gen_substrs(string &word)
+{
+	string substr, key;
+	set<string> substrs;
+	pair< map<string, set<string> >::iterator, bool > ret;
+
+	for (unsigned int i = 0; i < word.size(); i++) {
+		substr = word.substr(i, word.size());
+		for (unsigned int j = 1; j < substr.size() + 1; j++) {
+			key = substr.substr(0, j);
+			substrs.insert(key);
+		}
+	}
+
+	ret = substr_cache.insert( pair<string, set<string> >(word, substrs));
+	return &(ret.first->second);
+}
+
+static set<string> *find_substrs(string &word)
+{
+	map<string, set<string> >::iterator it;
+	it = substr_cache.find(word);
+	if (it == substr_cache.end()) {
+		misses++;
+		return gen_substrs(word);
+	} else {
+		hits++;
+		return &(it->second);
+	}
+}
+
+static void add_to_index(sid_t &songid, string key,
+			 map<string, set<sid_t> >*index)
+{
+	map<string, set<sid_t> >::iterator it;
+
+	it = index->find(key);
+	if (it != index->end())
+		it->second.insert(songid);
+	else {
+		set<sid_t> ids;
+		ids.insert(songid);
+		index->insert(pair<string, set<sid_t> >(key, ids));
+	}
+}
+
+static void index_word(sid_t &songid, string &word,
+		       map<string, set<sid_t> > *index)
+{
+	set<string> *substrs = find_substrs(word);
+	set<string>::iterator it;
+	for (it = substrs->begin(); it != substrs->end(); it++)
+		add_to_index(songid, *it, index);
+}
+
+static void index_tag(sid_t &songid, const string &tag,
+		      map<string, set<sid_t> >*index)
+{
+	list<string> *word_list;
+	list<string>::iterator it;
+
+	word_list = libsaria::format_text(tag);
+	for (it = word_list->begin(); it != word_list->end(); it++)
+		index_word(songid, *it, index);
+}
+
+namespace libsaria
+{
+
+	void index::add_track(libsaria::Track &track)
+	{
+		sid_t songid = track.get_songid();
+		index_tag(songid, track.get_artist(), &artist_index);
+		index_tag(songid, track.get_album(),  &album_index);
+		index_tag(songid, track.get_title(),  &title_index);
+	}
+
+	void index::print_stats()
+	{
+		println("Index cache hits: %u misses: %u", hits, misses);
+	}
+}

libsaria/library/file.cpp

@@ -3,6 +3,7 @@
  */
 
 #include <libsaria/library.h>
+#include <libsaria/index.h>
 #include "library.h"
 
 LibraryPath::LibraryPath(InFile &in, string dir)
@@ -14,8 +15,10 @@ LibraryPath::LibraryPath(InFile &in, string dir)
 	println("Library path dir: " + path);
 	println("Library path size: %d", size);
 
-	for (unsigned int i = 0; i < size; i++)
+	for (unsigned int i = 0; i < size; i++) {
 		file_list.push_back(libsaria::Track(in));
+		libsaria::index::add_track(file_list.back());
+	}
 }
 
 void LibraryPath::save(OutFile &out)

libsaria/libsaria.cpp

@@ -8,6 +8,7 @@
 #include <libsaria/print.h>
 #include <libsaria/library.h>
 #include <libsaria/format.h>
+#include <libsaria/index.h>
 
 namespace libsaria
 {
@@ -27,6 +28,7 @@ namespace libsaria
 	{
 		println("Quitting libsaria");
 		print_format_stats();
+		index::print_stats();
 	}
 
 };