From 23a518cf5aff8f75b4159565f2a6728e52455063 Mon Sep 17 00:00:00 2001
From: Anna Schumaker <schumaker.anna@gmail.com>
Date: Mon, 27 Jan 2014 10:23:22 -0500
Subject: [PATCH] playqueue: Sorting improvements

- Put empty tags last
- Correct and edge case in my binary search

Signed-off-by: Anna Schumaker <schumaker.anna@gmail.com>
---
 lib/playqueue.cpp | 36 +++++++++++++++++++++++++++++-------
 1 file changed, 29 insertions(+), 7 deletions(-)

diff --git a/lib/playqueue.cpp b/lib/playqueue.cpp
index dc8d1f1c..eb723857 100644
--- a/lib/playqueue.cpp
+++ b/lib/playqueue.cpp
@@ -112,6 +112,21 @@ static inline int compare_uint(unsigned int a, unsigned int b)
 	return 1;
 }
 
+/*
+ * Returns:
+ * 	  0: lhs == rhs
+ * 	< 0: lhs < rhs, or rhs is empty
+ * 	> 0: lhs > rhs, or lhs is empty
+ */
+static inline int compare_string(const std::string &a, const std::string &b)
+{
+	if (a.size() == 0)
+		return 1;
+	else if (b.size() == 0)
+		return -1;
+	return a.compare(b);
+}
+
 /*
  * std::string.compare() returns
  *	  0: Strings are equal
@@ -123,19 +138,19 @@ static inline int track_compare(library :: Song &lhs, library :: Song &rhs,
 {
 	switch (field) {
 	case SORT_ARTIST:
-		return lhs.artist->key_lower.compare(rhs.artist->key_lower);
+		return compare_string(lhs.artist->key_lower, rhs.artist->key_lower);
 	case SORT_ALBUM:
-		return lhs.album->name_lower.compare(rhs.album->name_lower);
+		return compare_string(lhs.album->name_lower, rhs.album->name_lower);
 	case SORT_COUNT:
 		return compare_uint(lhs.track->track, rhs.track->track);
 	case SORT_GENRE:
-		return lhs.genre->key_lower.compare(rhs.genre->key_lower);
+		return compare_string(lhs.genre->key_lower, rhs.genre->key_lower);
 	case SORT_LENGTH:
 		return compare_uint(lhs.track->length, rhs.track->length);
 	case SORT_PLAYED:
 		return compare_uint(lhs.track->play_count, rhs.track->play_count);
 	case SORT_TITLE:
-		return lhs.track->title_lower.compare(rhs.track->title_lower);
+		return compare_string(lhs.track->title_lower, rhs.track->title_lower);
 	case SORT_TRACK:
 		return compare_uint(lhs.track->track, rhs.track->track);
 	default: //case SORT_YEAR
@@ -170,17 +185,24 @@ unsigned int Playqueue :: add_sorted(unsigned int track_id, library :: Song &rhs
 		return 0;
 	}
 
-	while (start != end) {
+	while (end - start > 1) {
 		cur = start + ((end - start) / 2);
 		library :: lookup(tracks[cur], &lhs);
 		if (track_less_than(lhs, rhs, sort_order)) {
-			if (end - start == 1)
-				cur = end;
+			//if (end - start == 1)
+			//	cur = end;
 			start = cur;
 		} else
 			end = cur;
 	}
 
+	if (end - start == 1) {
+		cur = end;
+		library :: lookup(tracks[cur], &lhs);
+		if (track_less_than(lhs, rhs, sort_order))
+			cur++;
+	}
+
 	tracks.insert(tracks.begin() + cur, track_id);
 	return cur;
 }