diff --git a/include/libtorrent/string_util.hpp b/include/libtorrent/string_util.hpp
index 4ae4034e5..abd4e0073 100644
--- a/include/libtorrent/string_util.hpp
+++ b/include/libtorrent/string_util.hpp
@@ -53,6 +53,11 @@ namespace libtorrent {
 	// internal
 	inline bool is_digit(char c)
 	{ return c >= '0' && c <= '9'; }
+	inline void ensure_trailing_slash(std::string& url)
+	{
+		if (url.empty() || url[url.size() - 1] != '/')
+			url += '/';
+	}
 
 	TORRENT_EXTRA_EXPORT bool is_print(char c);
 	TORRENT_EXTRA_EXPORT bool is_space(char c);
diff --git a/src/http_parser.cpp b/src/http_parser.cpp
index bc7531c3d..3c19612f5 100644
--- a/src/http_parser.cpp
+++ b/src/http_parser.cpp
@@ -121,8 +121,7 @@ namespace libtorrent {
 			// however, we may still need to insert a '/' in case neither side
 			// has one. We know the location doesn't start with a / already.
 			// so, if the referrer doesn't end with one, add it.
-			if (url.empty() || url[url.size() - 1] != '/')
-				url += '/';
+			ensure_trailing_slash(url);
 			url += location;
 		}
 		return url;
diff --git a/src/torrent.cpp b/src/torrent.cpp
index f4503d016..96bb13a1c 100644
--- a/src/torrent.cpp
+++ b/src/torrent.cpp
@@ -265,7 +265,8 @@ namespace libtorrent {
 
 			// correct URLs to end with a "/" for multi-file torrents
 			std::string& url = ws.back().url;
-			if (multi_file && url[url.size()-1] != '/') url += '/';
+			if (multi_file)
+				ensure_trailing_slash(url);
 		}
 
 		for (auto const& e : p.http_seeds)
diff --git a/src/torrent_info.cpp b/src/torrent_info.cpp
index 9da7f9a77..2b3cba2fc 100644
--- a/src/torrent_info.cpp
+++ b/src/torrent_info.cpp
@@ -1460,7 +1460,8 @@ namespace libtorrent {
 		{
 			web_seed_entry ent(maybe_url_encode(url_seeds.string_value().to_string())
 				, web_seed_entry::url_seed);
-			if ((m_flags & multifile) && ent.url[ent.url.size() - 1] != '/') ent.url += '/';
+			if (m_flags & multifile)
+				ensure_trailing_slash(ent.url);
 			m_web_seeds.push_back(ent);
 		}
 		else if (url_seeds && url_seeds.type() == bdecode_node::list_t)
@@ -1474,7 +1475,8 @@ namespace libtorrent {
 				if (url.string_length() == 0) continue;
 				web_seed_entry ent(maybe_url_encode(url.string_value().to_string())
 					, web_seed_entry::url_seed);
-				if ((m_flags & multifile) && ent.url[ent.url.size() - 1] != '/') ent.url += '/';
+				if (m_flags & multifile)
+					ensure_trailing_slash(ent.url);
 				if (!unique.insert(ent.url).second) continue;
 				m_web_seeds.push_back(ent);
 			}
diff --git a/src/web_peer_connection.cpp b/src/web_peer_connection.cpp
index 13a376db9..df67247c2 100644
--- a/src/web_peer_connection.cpp
+++ b/src/web_peer_connection.cpp
@@ -95,8 +95,8 @@ web_peer_connection::web_peer_connection(peer_connection_args const& pack
 	{
 		// handle incorrect .torrent files which are multi-file
 		// but have web seeds not ending with a slash
-		if (m_path.empty() || m_path[m_path.size() - 1] != '/') m_path += '/';
-		if (m_url.empty() || m_url[m_url.size() - 1] != '/') m_url += '/';
+		ensure_trailing_slash(m_path);
+		ensure_trailing_slash(m_url);
 	}
 	else
 	{