X-Git-Url: https://main.carlh.net/gitweb/?a=blobdiff_plain;f=src%2Flib%2Fevent_history.cc;h=fca88aaf18a8b6a769d7a5fcb9cb9494d6ffa709;hb=037b18b34e3e3fd9b9e692d85f35de17ab67aff8;hp=eb3438aaba1397b747554b31b25d21e4b92c8c4e;hpb=6a11232620e0006f6a2b1e8d2b56e56d84229d5c;p=dcpomatic.git

diff --git a/src/lib/event_history.cc b/src/lib/event_history.cc
index eb3438aab..fca88aaf1 100644
--- a/src/lib/event_history.cc
+++ b/src/lib/event_history.cc
@@ -1,5 +1,5 @@
 /*
-    Copyright (C) 2017 Carl Hetherington <cth@carlh.net>
+    Copyright (C) 2017-2021 Carl Hetherington <cth@carlh.net>
 
     This file is part of DCP-o-matic.
 
@@ -18,22 +18,28 @@
 
 */
 
+
 #include "event_history.h"
 #include "util.h"
 #include <boost/thread/mutex.hpp>
 
+
+using boost::optional;
+
+
 EventHistory::EventHistory (int size)
 	: _size (size)
 {
 
 }
 
-float
+
+optional<float>
 EventHistory::rate () const
 {
 	boost::mutex::scoped_lock lock (_mutex);
-	if (int (_history.size()) < _size) {
-		return 0;
+	if (int(_history.size()) < _size) {
+		return {};
 	}
 
 	struct timeval now;
@@ -42,6 +48,7 @@ EventHistory::rate () const
 	return _size / (seconds (now) - seconds (_history.back ()));
 }
 
+
 void
 EventHistory::event ()
 {
@@ -50,7 +57,7 @@ EventHistory::event ()
 	struct timeval tv;
 	gettimeofday (&tv, 0);
 	_history.push_front (tv);
-	if (int (_history.size()) > _size) {
+	if (int(_history.size()) > _size) {
 		_history.pop_back ();
 	}
 }