From 2a7b90d6fb5c2803793fba02512d1f90b503b8b3 Mon Sep 17 00:00:00 2001
From: Leonard <nulaft@users.noreply.github.com>
Date: Sun, 6 Jun 2021 12:24:02 +0200
Subject: [PATCH] Fixes segmentation fault for empty pointclouds

See issue #1405
This small change fixes the issue where cartographer_rosbag_validate segfaults if the ros bag contains PointCloud2 messages without any points in them.
---
 cartographer_ros/cartographer_ros/rosbag_validate_main.cc | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/cartographer_ros/cartographer_ros/rosbag_validate_main.cc b/cartographer_ros/cartographer_ros/rosbag_validate_main.cc
index c52c70049..d14388246 100644
--- a/cartographer_ros/cartographer_ros/rosbag_validate_main.cc
+++ b/cartographer_ros/cartographer_ros/rosbag_validate_main.cc
@@ -219,7 +219,10 @@ class RangeDataChecker {
     const cartographer::sensor::TimedPointCloud& point_cloud =
         std::get<0>(point_cloud_time).points;
     *to = std::get<1>(point_cloud_time);
-    *from = *to + cartographer::common::FromSeconds(point_cloud[0].time);
+    *from = *to;
+    if (point_cloud.size() > 0) {
+      *from += cartographer::common::FromSeconds(point_cloud[0].time);
+    }
     Eigen::Vector4f points_sum = Eigen::Vector4f::Zero();
     for (const auto& point : point_cloud) {
       points_sum.head<3>() += point.position;