From 27365dcb1895006c35b79a16b322562feb6176da Mon Sep 17 00:00:00 2001
From: trylock <lothar.gordon@gmail.com>
Date: Thu, 31 Jan 2019 23:02:54 +0100
Subject: [PATCH] Fix: correctly remove packet trailer

---
 XmpCore.Tests/XmpUtilsTests.cs | 17 ++++++++++++++++-
 XmpCore/Impl/XmpUtils.cs       |  4 +++-
 2 files changed, 19 insertions(+), 2 deletions(-)

diff --git a/XmpCore.Tests/XmpUtilsTests.cs b/XmpCore.Tests/XmpUtilsTests.cs
index 9442b32..0f264f0 100644
--- a/XmpCore.Tests/XmpUtilsTests.cs
+++ b/XmpCore.Tests/XmpUtilsTests.cs
@@ -1,4 +1,6 @@
-using Xunit;
+using System.Text;
+using XmpCore.Impl;
+using Xunit;
 
 namespace XmpCore.Tests
 {
@@ -31,5 +33,18 @@ public void ConvertToLong()
             Assert.Throws<XmpException>(() => XmpUtils.ConvertToLong(null));
             Assert.Throws<XmpException>(() => XmpUtils.ConvertToLong("Foo"));
         }
+
+        [Fact]
+        public void PackageEmptyXmpDataToJPEG()
+        {
+            IXmpMeta data = new XmpMeta();
+            StringBuilder standard = new StringBuilder();
+            StringBuilder extended = new StringBuilder();
+            StringBuilder digest = new StringBuilder();
+
+            XmpUtils.PackageForJPEG(data, standard, extended, digest);
+            
+            Assert.Equal(0, extended.Length);
+        }
     }
 }
\ No newline at end of file
diff --git a/XmpCore/Impl/XmpUtils.cs b/XmpCore/Impl/XmpUtils.cs
index a3b9b06..bc633ae 100644
--- a/XmpCore/Impl/XmpUtils.cs
+++ b/XmpCore/Impl/XmpUtils.cs
@@ -1477,7 +1477,9 @@ string ByteArrayToHexString(byte[] bytes)
             if (extraPadding > 2047)
                 extraPadding = 2047;
             //stdStr.delete(stdStr.toString().indexOf(kPacketTrailer), stdStr.length());
-            stdStr.Remove(stdStr.ToString().IndexOf(kPacketTrailer), stdStr.Length);
+            int index = stdStr.ToString().IndexOf(kPacketTrailer);
+            int length = stdStr.Length - index;
+            stdStr.Remove(index, length);
 
             stdStr.Append(' ', extraPadding);