Compile the PR #65 in MDE repo in a separate library

.gitignore

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+.vs
+bin
+obj

Directory.Packages.props

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+<Project>
+  <!-- Enable central package version management -->
+  <PropertyGroup>
+    <ManagePackageVersionsCentrally>true</ManagePackageVersionsCentrally>
+    <CentralPackageTransitivePinningEnabled>true</CentralPackageTransitivePinningEnabled>
+  </PropertyGroup>
+  <!-- Setup tools to be installed in all projects -->
+  <ItemGroup>
+    <!-- Built into the .NET 8 SDK -->
+    <!-- <GlobalPackageReference Include="Microsoft.SourceLink.AzureRepos.Git" Version="1.1.1" /> -->
+  </ItemGroup>
+  <!-- Centrally defined package versions -->
+  <ItemGroup>
+    <PackageVersion Include="JetBrains.Annotations" Version="2023.3.0" />
+    <PackageVersion Include="MetadataExtractor" Version="2.9.0-rc1" />
+    <PackageVersion Include="xunit.assert" Version="2.7.0" />
+    <PackageVersion Include="Microsoft.NET.Test.Sdk" Version="17.6.0" />
+    <PackageVersion Include="coverlet.collector" Version="6.0.0" />
+    <PackageVersion Include="xunit" Version="2.7.0" />
+    <PackageVersion Include="xunit.analyzers" Version="1.11.0" />
+    <PackageVersion Include="xunit.runner.visualstudio" Version="2.5.7" />
+  </ItemGroup>
+</Project>

JpegXmpWritePluginMDE.Tests/Data/xmpWriting_XmpContent.xmp

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+<x:xmpmeta xmlns:x="adobe:ns:meta/"><rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"><rdf:Description rdf:about="uuid:faf5bdd5-ba3d-11da-ad31-d33d75182f1b" xmlns:xmp="http://ns.adobe.com/xap/1.0/"><xmp:CreatorTool>Microsoft Photo Gallery 16.4.3528.331</xmp:CreatorTool></rdf:Description><rdf:Description rdf:about="uuid:faf5bdd5-ba3d-11da-ad31-d33d75182f1b" xmlns:MP="http://ns.microsoft.com/photo/1.2/"><MP:RegionInfo><rdf:Description xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"><MPRI:Regions xmlns:MPRI="http://ns.microsoft.com/photo/1.2/t/RegionInfo#"><rdf:Bag xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"><rdf:li><rdf:Description xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"><MPReg:Rectangle xmlns:MPReg="http://ns.microsoft.com/photo/1.2/t/Region#">0.028800, 0.158273, 0.152000, 0.230216</MPReg:Rectangle><MPReg:PersonDisplayName xmlns:MPReg="http://ns.microsoft.com/photo/1.2/t/Region#">Sean Connery</MPReg:PersonDisplayName></rdf:Description>
+							</rdf:li><rdf:li><rdf:Description xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"><MPReg:Rectangle xmlns:MPReg="http://ns.microsoft.com/photo/1.2/t/Region#">0.257600, 0.141487, 0.128000, 0.191847</MPReg:Rectangle><MPReg:PersonDisplayName xmlns:MPReg="http://ns.microsoft.com/photo/1.2/t/Region#">Roger Moore</MPReg:PersonDisplayName></rdf:Description>
+							</rdf:li><rdf:li><rdf:Description xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"><MPReg:Rectangle xmlns:MPReg="http://ns.microsoft.com/photo/1.2/t/Region#">0.433600, 0.184652, 0.128000, 0.191847</MPReg:Rectangle><MPReg:PersonDisplayName xmlns:MPReg="http://ns.microsoft.com/photo/1.2/t/Region#">Daniel Craig</MPReg:PersonDisplayName></rdf:Description>
+							</rdf:li><rdf:li><rdf:Description xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"><MPReg:Rectangle xmlns:MPReg="http://ns.microsoft.com/photo/1.2/t/Region#">0.617600, 0.194245, 0.120000, 0.179856</MPReg:Rectangle><MPReg:PersonDisplayName xmlns:MPReg="http://ns.microsoft.com/photo/1.2/t/Region#">Timothy Dalton</MPReg:PersonDisplayName></rdf:Description>
+							</rdf:li><rdf:li><rdf:Description xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"><MPReg:Rectangle xmlns:MPReg="http://ns.microsoft.com/photo/1.2/t/Region#">0.825600, 0.206235, 0.136000, 0.203837</MPReg:Rectangle><MPReg:PersonDisplayName xmlns:MPReg="http://ns.microsoft.com/photo/1.2/t/Region#">Pierce Brosnan</MPReg:PersonDisplayName></rdf:Description>
+							</rdf:li></rdf:Bag>
+					</MPRI:Regions></rdf:Description>
+			</MP:RegionInfo></rdf:Description></rdf:RDF></x:xmpmeta>

JpegXmpWritePluginMDE.Tests/Formats/Jpeg/JpegFragmentTest.cs

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+#region License
+//
+// Copyright 2002-2017 Drew Noakes
+// Ported from Java to C# by Yakov Danilov for Imazen LLC in 2014
+//
+//    Licensed under the Apache License, Version 2.0 (the "License");
+//    you may not use this file except in compliance with the License.
+//    You may obtain a copy of the License at
+//
+//        http://www.apache.org/licenses/LICENSE-2.0
+//
+//    Unless required by applicable law or agreed to in writing, software
+//    distributed under the License is distributed on an "AS IS" BASIS,
+//    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+//    See the License for the specific language governing permissions and
+//    limitations under the License.
+//
+// More information about this project is available at:
+//
+//    https://github.com/drewnoakes/metadata-extractor-dotnet
+//    https://drewnoakes.com/code/exif/
+//
+#endregion
+
+using JpegXmpWritePluginMDE.MetadataExtractor.Formats.Jpeg;
+using MetadataExtractor.Formats.Jpeg;
+using MetadataExtractor.IO;
+using Xunit;
+
+namespace JpegXmpWritePluginMDE.Tests.Formats.Jpeg
+{
+	/// <summary>Unit tests for <see cref="JpegFragment"/>.</summary>
+	/// <author>Michael Osthege</author>
+	public sealed class JpegFragmentTest
+	{
+
+		[Fact]
+		public void TestSplitSingleFragment()
+		{
+			// The test file contains exactly one App1 XMP segment (marker, size, payload)
+			string pathApp1 = "Data/xmpWriting_MicrosoftXmp.app1";
+
+			List<JpegFragment> fragments;
+			using (var stream = TestDataUtil.OpenRead(pathApp1))
+				fragments = JpegFragmentWriter.SplitFragments(new SequentialStreamReader(stream));
+			byte[] fileBytes = TestDataUtil.GetBytes(pathApp1);
+
+			Assert.Single(fragments);
+			Assert.True(fragments.First().Bytes.SequenceEqual(fileBytes));
+			Assert.NotNull(fragments.First().Segment);
+			Assert.Equal(JpegSegmentType.App1, fragments.First().Segment.Type);
+		}
+
+		[Fact]
+		public void TestFindsFragment()
+		{
+			// The file is an image that contains an App1 Xmp segment
+			string pathJpeg = "Data/xmpWriting_PictureWithMicrosoftXmp.jpg";
+			string pathApp1 = "Data/xmpWriting_MicrosoftXmp.app1";
+
+			List<JpegFragment> fragments;
+			using (var stream = TestDataUtil.OpenRead(pathJpeg))
+				fragments = JpegFragmentWriter.SplitFragments(new SequentialStreamReader(stream));
+			byte[] xmpFragmentBytes = TestDataUtil.GetBytes(pathApp1);
+
+			bool foundXmpFragment = false;
+			foreach (var fragment in fragments)
+			{
+				if (fragment.Bytes.Length == xmpFragmentBytes.Length)
+				{
+					Assert.True(fragment.Bytes.SequenceEqual(xmpFragmentBytes));
+					foundXmpFragment = true;
+				}
+			}
+			Assert.True(foundXmpFragment, "The Xmp App1 fragment was not found correctly.");
+		}
+
+		[Fact]
+		public void TestSplitConcatenation()
+		{
+			// The file is an image that contains an App1 Xmp segment
+			string pathJpeg = "Data/xmpWriting_PictureWithMicrosoftXmp.jpg";
+
+			List<JpegFragment> fragments;
+			using (var stream = TestDataUtil.OpenRead(pathJpeg))
+				fragments = JpegFragmentWriter.SplitFragments(new SequentialStreamReader(stream));
+			byte[] original = File.ReadAllBytes(pathJpeg);
+
+			int nRead = fragments.Select(f => f.Bytes.Length).Sum();
+			byte[] joined = JpegFragmentWriter.JoinFragments(fragments).ToArray();
+
+			Assert.Equal(original.Length, nRead);
+			Assert.Equal(original.Length, joined.Length);
+			Assert.True(original.SequenceEqual(joined));
+		}
+
+	}
+}

JpegXmpWritePluginMDE.Tests/Formats/Jpeg/JpegMetadataWriterTest.cs

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+#region License
+//
+// Copyright 2002-2017 Drew Noakes
+// Ported from Java to C# by Yakov Danilov for Imazen LLC in 2014
+//
+//    Licensed under the Apache License, Version 2.0 (the "License");
+//    you may not use this file except in compliance with the License.
+//    You may obtain a copy of the License at
+//
+//        http://www.apache.org/licenses/LICENSE-2.0
+//
+//    Unless required by applicable law or agreed to in writing, software
+//    distributed under the License is distributed on an "AS IS" BASIS,
+//    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+//    See the License for the specific language governing permissions and
+//    limitations under the License.
+//
+// More information about this project is available at:
+//
+//    https://github.com/drewnoakes/metadata-extractor-dotnet
+//    https://drewnoakes.com/code/exif/
+//
+#endregion
+using JpegXmpWritePluginMDE.MetadataExtractor.Formats.Jpeg;
+using MetadataExtractor.Formats.Jpeg;
+using MetadataExtractor.IO;
+using System.Xml.Linq;
+using XmpCore;
+using Xunit;
+
+namespace JpegXmpWritePluginMDE.Tests.Formats.Jpeg
+{
+	/// <summary>Unit tests for <see cref="JpegMetadataWriter"/>.</summary>
+	/// <author>Michael Osthege</author>
+	public sealed class JpegMetadataWriterTest
+	{
+		/// <summary>
+		/// This test is very similar to <see cref="MetadataExtractor.Tests.Formats.Xmp.XmpWriterTest.TestUpdateFragments_Replace"/>
+		/// but acts on one abstraction level higher, using a collection of metadata objects.
+		/// It tests if the <see cref="JpegMetadataWriter.UpdateJpegFragments()"/> correctly uses a
+		/// compatible metadata writer.
+		/// </summary>
+		[Fact]
+		public void TestUpdateJpegFragments_Replace()
+		{
+			// substitute the original with re-encoded Xmp content
+			List<JpegFragment> originalFragments = null;
+			using (var stream = TestDataUtil.OpenRead("Data/xmpWriting_PictureWithMicrosoftXmp.jpg"))
+				originalFragments = JpegFragmentWriter.SplitFragments(new SequentialStreamReader(stream));
+			IXmpMeta xmp = XmpMetaFactory.ParseFromString(File.ReadAllText("Data/xmpWriting_XmpContent.xmp"));
+			byte[] originalApp1 = File.ReadAllBytes("Data/xmpWriting_MicrosoftXmp.app1");
+			byte[] expectedApp1 = File.ReadAllBytes("Data/xmpWriting_MicrosoftXmpReencoded.app1");
+
+			var metadata_objects = new object[] { xmp };
+			var updatedFragments = JpegMetadataWriter.UpdateJpegFragments(originalFragments, metadata_objects);
+
+			Assert.Equal(originalFragments.Count, updatedFragments.Count);
+			// Check that only the App1 Xmp fragment is modified
+			for (int i = 0; i < originalFragments.Count; i++)
+			{
+				var ofrag = originalFragments[i];
+				var ufrag = updatedFragments[i];
+
+				if (ofrag.Segment?.Type == JpegSegmentType.App1 && ofrag.Bytes.SequenceEqual(originalApp1))
+				{
+					// If this fragment is the original Xmp fragment, we expect the updated fragment
+					Assert.True(ufrag.Bytes.SequenceEqual(expectedApp1));
+				}
+				else
+				{
+					// In all other cases, the fragments must remain identical
+					Assert.True(ufrag.Bytes.SequenceEqual(ofrag.Bytes));
+				}
+			}
+		}
+
+		[Fact]
+		public void TestUpdateJpegFragments_FailsOnUnknownMetadataObject()
+		{
+			// substitute the original with re-encoded Xmp content
+			List<JpegFragment> originalFragments = null;
+			using (var stream = TestDataUtil.OpenRead("Data/xmpWriting_PictureWithMicrosoftXmp.jpg"))
+				originalFragments = JpegFragmentWriter.SplitFragments(new SequentialStreamReader(stream));
+			IXmpMeta xmp = XmpMetaFactory.ParseFromString(File.ReadAllText("Data/xmpWriting_XmpContent.xmp"));
+
+			Assert.Throws<NotImplementedException>(delegate
+			{
+				var metadata_objects = new object[] { xmp, "This is not a supported metadata object." };
+				var updatedFragments = JpegMetadataWriter.UpdateJpegFragments(originalFragments, metadata_objects);
+			});
+		}
+
+		[Fact]
+		public void TestWriteJpegMetadata()
+		{
+			var originalStream = TestDataUtil.OpenRead("Data/xmpWriting_PictureWithMicrosoftXmp.jpg");
+			IXmpMeta xmp = XmpMetaFactory.ParseFromString(File.ReadAllText("Data/xmpWriting_XmpContent.xmp"));
+			byte[] expectedResult = TestDataUtil.GetBytes("Data/xmpWriting_PictureWithMicrosoftXmpReencoded.jpg");
+
+			var metadata_objects = new object[] { xmp };
+			var updatedStream = JpegMetadataWriter.WriteMetadata(originalStream, metadata_objects);
+
+			var actualResult = updatedStream.ToArray();
+
+			Assert.True(actualResult.SequenceEqual(expectedResult));
+		}
+	}
+}

JpegXmpWritePluginMDE.Tests/Formats/Jpeg/JpegSegmentTest.cs

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+#region License
+//
+// Copyright 2002-2017 Drew Noakes
+// Ported from Java to C# by Yakov Danilov for Imazen LLC in 2014
+//
+//    Licensed under the Apache License, Version 2.0 (the "License");
+//    you may not use this file except in compliance with the License.
+//    You may obtain a copy of the License at
+//
+//        http://www.apache.org/licenses/LICENSE-2.0
+//
+//    Unless required by applicable law or agreed to in writing, software
+//    distributed under the License is distributed on an "AS IS" BASIS,
+//    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+//    See the License for the specific language governing permissions and
+//    limitations under the License.
+//
+// More information about this project is available at:
+//
+//    https://github.com/drewnoakes/metadata-extractor-dotnet
+//    https://drewnoakes.com/code/exif/
+//
+#endregion
+
+using System.Collections.Generic;
+using System.IO;
+using System.Linq;
+using JpegXmpWritePluginMDE.MetadataExtractor.Formats.Jpeg;
+using MetadataExtractor.Formats.Jpeg;
+using MetadataExtractor.IO;
+using Xunit;
+
+namespace JpegXmpWritePluginMDE.Tests.Formats.Jpeg
+{
+	/// <summary>Unit tests for <see cref="JpegSegment"/>.</summary>
+	/// <author>Michael Osthege</author>
+	public sealed class JpegSegmentTest
+	{
+		[Fact]
+		public void TestEncodeSegmentLength()
+		{
+			// we are just interested in the payload length
+			int expected = 42802 - 2;
+			// the encoded value is 42802 because it includes the length mark
+			byte[] encoded = new byte[] { 0xA7, 0x32 };
+			int decoded = JpegSegmentPlugin.DecodePayloadLength(encoded[0], encoded[1]);
+
+			Assert.Equal(expected, decoded);
+		}
+
+		[Fact]
+		public void TestDecodeSegmentLength()
+		{
+			int decoded = 42802 - 2;
+			byte[] expected = new byte[] { 0xA7, 0x32 };
+			byte[] encoded = JpegSegmentPlugin.EncodePayloadLength(decoded);
+
+			Assert.True(encoded.SequenceEqual(expected));
+		}
+	}
+}