From 26c42ee72cc085b2195a5045c11038f508d01c82 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Henrik=20M=C3=B6ller?= <henri.moller@carmenta.tech>
Date: Thu, 12 Jan 2023 13:22:59 +0100
Subject: [PATCH] Fix decoding of PointAlongLine messages with no positive
 offset byte

---
 .../Binary/Codecs/PointAlongLineLocationCodec.cs  |  2 +-
 .../Binary/PointAlongLineLocationTests.cs         | 15 +++++++++++++++
 2 files changed, 16 insertions(+), 1 deletion(-)

diff --git a/src/OpenLR/Codecs/Binary/Codecs/PointAlongLineLocationCodec.cs b/src/OpenLR/Codecs/Binary/Codecs/PointAlongLineLocationCodec.cs
index 5747036..878ba25 100644
--- a/src/OpenLR/Codecs/Binary/Codecs/PointAlongLineLocationCodec.cs
+++ b/src/OpenLR/Codecs/Binary/Codecs/PointAlongLineLocationCodec.cs
@@ -57,7 +57,7 @@ public static PointAlongLineLocation Decode(byte[] data)
             pointAlongLine.First = first;
             pointAlongLine.Orientation = OrientationConverter.Decode(data, 7, 0);
             pointAlongLine.SideOfRoad = SideOfRoadConverter.Decode(data, 14, 0);
-            pointAlongLine.PositiveOffsetPercentage = OffsetConvertor.Decode(data, 16);
+            pointAlongLine.PositiveOffsetPercentage = data.Length > 16 ? OffsetConvertor.Decode(data, 16) : null;
             pointAlongLine.Last = last;
 
             return pointAlongLine;
diff --git a/test/OpenLR.Test/Binary/PointAlongLineLocationTests.cs b/test/OpenLR.Test/Binary/PointAlongLineLocationTests.cs
index 6efe69e..b20a3cb 100644
--- a/test/OpenLR.Test/Binary/PointAlongLineLocationTests.cs
+++ b/test/OpenLR.Test/Binary/PointAlongLineLocationTests.cs
@@ -6,6 +6,8 @@
 
 namespace OpenLR.Test.Binary
 {
+    using NuGet.Frameworks;
+
     /// <summary>
     /// Contains tests for decoding/encoding a point along location to/from OpenLR binary representation.
     /// </summary>
@@ -53,6 +55,19 @@ public void DecodeBase64Test()
             Assert.AreEqual(SideOfRoad.Left, pointAlongLineLocation.SideOfRoad);
             Assert.AreEqual(30.19, pointAlongLineLocation.PositiveOffsetPercentage, 0.5); // binary encode loses accuracy.
         }
+        
+        /// <summary>
+        /// Decode a message with only 16 bytes, i.e. no positive offset byte
+        /// </summary>
+        [Test]
+        public void DecodeBase64WithNoOffset()
+        {
+            // Message with 16 bytes.
+            var stringData = Convert.FromBase64String("Kwhv2ikWNjPZAP/XAAUzCA==");
+            
+            Assert.IsTrue(PointAlongLineLocationCodec.CanDecode(stringData));
+            Assert.DoesNotThrow(() => PointAlongLineLocationCodec.Decode(stringData));
+        }
 
         /// <summary>
         /// A simple test encoding from a base64 string.