From 4c64da9ce5d22ccf6d98b0dc34a5debd9222130f Mon Sep 17 00:00:00 2001
From: Seth Alves <seth.alves@gmail.com>
Date: Tue, 27 Oct 2015 10:27:32 -0700
Subject: [PATCH] try to avoid negative roll-over when moving to or from server
 time

---
 libraries/physics/src/ObjectAction.cpp | 18 ++++++++++++++++--
 1 file changed, 16 insertions(+), 2 deletions(-)

diff --git a/libraries/physics/src/ObjectAction.cpp b/libraries/physics/src/ObjectAction.cpp
index 8ed06aea5d..ff8382a143 100644
--- a/libraries/physics/src/ObjectAction.cpp
+++ b/libraries/physics/src/ObjectAction.cpp
@@ -247,15 +247,29 @@ bool ObjectAction::lifetimeIsOver() {
 }
 
 quint64 ObjectAction::localTimeToServerTime(quint64 timeValue) const {
+    // 0 indicates no expiration
     if (timeValue == 0) {
         return 0;
     }
-    return timeValue + getEntityServerClockSkew();
+
+    int serverClockSkew = getEntityServerClockSkew();
+    if (serverClockSkew < 0 && timeValue <= (quint64)(-serverClockSkew)) {
+        return 1; // non-zero but long-expired value to avoid negative roll-over
+    }
+
+    return timeValue + serverClockSkew;
 }
 
 quint64 ObjectAction::serverTimeToLocalTime(quint64 timeValue) const {
+    // 0 indicates no expiration
     if (timeValue == 0) {
         return 0;
     }
-    return timeValue - getEntityServerClockSkew();
+
+    int serverClockSkew = getEntityServerClockSkew();
+    if (serverClockSkew > 0 && timeValue <= (quint64)serverClockSkew) {
+        return 1; // non-zero but long-expired value to avoid negative roll-over
+    }
+
+    return timeValue - serverClockSkew;
 }