From 216cb7e356870195f485a9a95c98fc6e94a64908 Mon Sep 17 00:00:00 2001
From: Matt Joiner <anacrolix@gmail.com>
Date: Tue, 17 Jul 2018 15:08:46 +1000
Subject: [PATCH] Don't randomize chunk order for requestStrategy 3

This should also reduce a lot of allocation.
---
 connection.go | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/connection.go b/connection.go
index d1aa9fcb..56a0ee5b 100644
--- a/connection.go
+++ b/connection.go
@@ -789,6 +789,17 @@ func (cn *connection) iterPendingRequests(piece pieceIndex, f func(request) bool
 }
 
 func iterUndirtiedChunks(piece pieceIndex, t *Torrent, f func(chunkSpec) bool) bool {
+	p := &t.pieces[piece]
+	if t.requestStrategy == 3 {
+		for i := pp.Integer(0); i < p.numChunks(); i++ {
+			if !p.dirtyChunks.Get(bitmap.BitIndex(i)) {
+				if !f(t.chunkIndexSpec(i, piece)) {
+					return false
+				}
+			}
+		}
+		return true
+	}
 	chunkIndices := t.pieces[piece].undirtiedChunkIndices().ToSortedSlice()
 	// TODO: Use "math/rand".Shuffle >= Go 1.10
 	return iter.ForPerm(len(chunkIndices), func(i int) bool {
-- 
2.48.1