From 362acf163b04480defb157237ace1e69fc77be04 Mon Sep 17 00:00:00 2001
From: Anna Schumaker <schumaker.anna@gmail.com>
Date: Tue, 28 Jan 2014 09:42:38 -0500
Subject: [PATCH] playqueue: More sorting improvements

- Reimplement binary search for neater code
- Flip sort order when resetting sort if the first field is the one we
  are sorting by.

Signed-off-by: Anna Schumaker <schumaker.anna@gmail.com>
---
 include/playqueue.h |  2 +-
 lib/playqueue.cpp   | 52 +++++++++++++++++----------------------------
 2 files changed, 21 insertions(+), 33 deletions(-)

diff --git a/include/playqueue.h b/include/playqueue.h
index 779a238a..7234cffe 100644
--- a/include/playqueue.h
+++ b/include/playqueue.h
@@ -42,7 +42,7 @@ private:
 	unsigned int cur;
 	unsigned int length;
 
-	unsigned int add_sorted(unsigned int, library :: Song &);
+	unsigned int find_sorted_id(library :: Song &);
 	void _add_sort(sort_t);
 
 public:
diff --git a/lib/playqueue.cpp b/lib/playqueue.cpp
index c2d1555f..6a5b895e 100644
--- a/lib/playqueue.cpp
+++ b/lib/playqueue.cpp
@@ -178,43 +178,31 @@ static bool track_less_than(library :: Song &lhs, library :: Song &rhs,
 	return res;
 }
 
-unsigned int Playqueue :: add_sorted(unsigned int track_id, library :: Song &rhs)
+unsigned int Playqueue :: find_sorted_id(library :: Song &rhs)
 {
 	library :: Song lhs;
-	unsigned int cur, start = 0, end = (tracks.size() - 1);
+	unsigned int begin = 0, end = (tracks.size() - 1), mid;
 
-	if (tracks.size() == 0) {
-		tracks.push_back(track_id);
+	if (tracks.size() == 0)
 		return 0;
-	} else if (tracks.size() == 1) {
-		library :: lookup(tracks[0], &lhs);
-		if (track_less_than(lhs, rhs, sort_order)) {
-			tracks.push_back(track_id);
-			return 1;
-		}
-		tracks.insert(tracks.begin(), track_id);
-		return 0;
-	}
 
-	while (end - start > 1) {
-		cur = start + ((end - start) / 2);
-		library :: lookup(tracks[cur], &lhs);
+	while (end > begin) {
+		mid = begin + ((end - begin) / 2);
+		library :: lookup(tracks[mid], &lhs);
 		if (track_less_than(lhs, rhs, sort_order))
-			start = cur;
-		else
-			end = cur;
-	}
-
-	if (end != start) {
-		for (cur = start; cur <= end; cur++) {
-			library :: lookup(tracks[cur], &lhs);
-			if (!track_less_than(lhs, rhs, sort_order))
-				break;
+			begin = mid + 1;
+		else {
+			if (mid == begin)
+				return begin;
+			else
+				end = mid - 1;
 		}
 	}
 
-	tracks.insert(tracks.begin() + cur, track_id);
-	return cur;
+	library :: lookup(tracks[begin], &lhs);
+	if (track_less_than(lhs, rhs, sort_order))
+		return begin + 1;
+	return begin;
 }
 
 unsigned int Playqueue :: add(unsigned int track_id)
@@ -224,10 +212,9 @@ unsigned int Playqueue :: add(unsigned int track_id)
 	library :: lookup(track_id, &song);
 
 	if (sort_order.size() > 0)
-		add_sorted(track_id, song);
-	else
-		tracks.push_back(track_id);
+		id = find_sorted_id(song);
 
+	tracks.insert(tracks.begin() + id, track_id);
 	length += song.track->length;
 	get_callbacks()->on_queue_track_add(this, id);
 	if (!(flags & PQ_DISABLE_CHANGED_SIZE))
@@ -330,7 +317,8 @@ void Playqueue :: reset_sort(sort_t field)
 {
 	if (flags & PQ_NEVER_SORT)
 		return;
-	sort_order.clear();
+	if (sort_order.front().field != field)
+		sort_order.clear();
 	add_sort(field);
 }