From e4ed68918b0b7bf3e66ce633180bf09fb7577840 Mon Sep 17 00:00:00 2001
From: Arvid Norberg <arvid@libtorrent.org>
Date: Tue, 16 Dec 2008 01:26:35 +0000
Subject: [PATCH] fixed bug when torrent file have announce-list but no valid
 trackers. #444

---
 ChangeLog            |  2 ++
 src/torrent_info.cpp | 23 +++++++++++++----------
 2 files changed, 15 insertions(+), 10 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index 662fb51c0..9aeedd717 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -25,6 +25,8 @@ release 0.14.2
 	* removed support for boost-1.33 and earlier (probably didn't work)
 	* fixed potential freezes issues at shutdown
 	* improved error message for python setup script
+	* fixed bug when torrent file included announce-list, but no valid
+	  tracker urls
 
 release 0.14.1
 
diff --git a/src/torrent_info.cpp b/src/torrent_info.cpp
index a75dcf225..9aeb6e1b9 100644
--- a/src/torrent_info.cpp
+++ b/src/torrent_info.cpp
@@ -575,20 +575,23 @@ namespace libtorrent
 				}
 			}
 
-			// shuffle each tier
-			std::vector<announce_entry>::iterator start = m_urls.begin();
-			std::vector<announce_entry>::iterator stop;
-			int current_tier = m_urls.front().tier;
-			for (stop = m_urls.begin(); stop != m_urls.end(); ++stop)
+			if (!m_urls.empty())
 			{
-				if (stop->tier != current_tier)
+				// shuffle each tier
+				std::vector<announce_entry>::iterator start = m_urls.begin();
+				std::vector<announce_entry>::iterator stop;
+				int current_tier = m_urls.front().tier;
+				for (stop = m_urls.begin(); stop != m_urls.end(); ++stop)
 				{
-					std::random_shuffle(start, stop);
-					start = stop;
-					current_tier = stop->tier;
+					if (stop->tier != current_tier)
+					{
+						std::random_shuffle(start, stop);
+						start = stop;
+						current_tier = stop->tier;
+					}
 				}
+				std::random_shuffle(start, stop);
 			}
-			std::random_shuffle(start, stop);
 		}