Fix SilkMarshal.PtrToStringArray ignores the encoding parameter (#2376)

* Add Silk.NET.Core.Tests project

* Add test cases for testing string encoding

* Fix issue where PtrToStringArray was ignoring the encoding parameter

Author: Exanite

Silk.NET.sln

@@ -618,6 +618,8 @@ Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Silk.NET.OpenXR.Extensions.
 EndProject
 Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Silk.NET.Assimp.Tests", "src\Assimp\Silk.NET.Assimp.Tests\Silk.NET.Assimp.Tests.csproj", "{12D0A556-7DDF-4902-8911-1DA3F6331149}"
 EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Silk.NET.Core.Tests", "src\Core\Silk.NET.Core.Tests\Silk.NET.Core.Tests.csproj", "{4D871493-0B88-477A-99A1-3E05561CFAD9}"
+EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|Any CPU = Debug|Any CPU
@@ -3771,6 +3773,18 @@ Global
 		{12D0A556-7DDF-4902-8911-1DA3F6331149}.Release|x64.Build.0 = Release|Any CPU
 		{12D0A556-7DDF-4902-8911-1DA3F6331149}.Release|x86.ActiveCfg = Release|Any CPU
 		{12D0A556-7DDF-4902-8911-1DA3F6331149}.Release|x86.Build.0 = Release|Any CPU
+		{4D871493-0B88-477A-99A1-3E05561CFAD9}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{4D871493-0B88-477A-99A1-3E05561CFAD9}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{4D871493-0B88-477A-99A1-3E05561CFAD9}.Debug|x64.ActiveCfg = Debug|Any CPU
+		{4D871493-0B88-477A-99A1-3E05561CFAD9}.Debug|x64.Build.0 = Debug|Any CPU
+		{4D871493-0B88-477A-99A1-3E05561CFAD9}.Debug|x86.ActiveCfg = Debug|Any CPU
+		{4D871493-0B88-477A-99A1-3E05561CFAD9}.Debug|x86.Build.0 = Debug|Any CPU
+		{4D871493-0B88-477A-99A1-3E05561CFAD9}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{4D871493-0B88-477A-99A1-3E05561CFAD9}.Release|Any CPU.Build.0 = Release|Any CPU
+		{4D871493-0B88-477A-99A1-3E05561CFAD9}.Release|x64.ActiveCfg = Release|Any CPU
+		{4D871493-0B88-477A-99A1-3E05561CFAD9}.Release|x64.Build.0 = Release|Any CPU
+		{4D871493-0B88-477A-99A1-3E05561CFAD9}.Release|x86.ActiveCfg = Release|Any CPU
+		{4D871493-0B88-477A-99A1-3E05561CFAD9}.Release|x86.Build.0 = Release|Any CPU
 	EndGlobalSection
 	GlobalSection(SolutionProperties) = preSolution
 		HideSolutionNode = FALSE
@@ -4072,6 +4086,7 @@ Global
 		{25ABCA5E-4FF6-43ED-9A5E-443E1373EC5C} = {90471225-AC23-424E-B62E-F6EC4C6ECAC0}
 		{01B6FFA0-5B37-44EA-ABDF-7BABD05874C5} = {90471225-AC23-424E-B62E-F6EC4C6ECAC0}
 		{12D0A556-7DDF-4902-8911-1DA3F6331149} = {6EADA376-E83F-40B7-9539-71DD17AEF7A4}
+		{4D871493-0B88-477A-99A1-3E05561CFAD9} = {0651C5EF-50AA-4598-8D9C-8F210ADD8490}
 	EndGlobalSection
 	GlobalSection(ExtensibilityGlobals) = postSolution
 		SolutionGuid = {F5273D7F-3334-48DF-94E3-41AE6816CD4D}

src/Core/Silk.NET.Core.Tests/Silk.NET.Core.Tests.csproj

@@ -0,0 +1,30 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+    <PropertyGroup>
+        <TargetFrameworks>net6.0</TargetFrameworks>
+        <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
+        <LangVersion>preview</LangVersion>
+        <Nullable>enable</Nullable>
+
+        <IsPackable>false</IsPackable>
+    </PropertyGroup>
+
+    <ItemGroup>
+        <ProjectReference Include="..\Silk.NET.Core\Silk.NET.Core.csproj" />
+    </ItemGroup>
+
+    <ItemGroup>
+        <PackageReference Include="Microsoft.CodeAnalysis.CSharp" Version="3.11.0" />
+        <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.8.0" />
+        <PackageReference Include="xunit" Version="2.6.6" />
+        <PackageReference Include="xunit.runner.visualstudio" Version="2.5.6">
+            <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
+            <PrivateAssets>all</PrivateAssets>
+        </PackageReference>
+        <PackageReference Include="coverlet.collector" Version="6.0.0">
+            <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
+            <PrivateAssets>all</PrivateAssets>
+        </PackageReference>
+    </ItemGroup>
+
+</Project>

src/Core/Silk.NET.Core.Tests/TestSilkMarshal.cs

@@ -0,0 +1,51 @@
+using System.Collections.Generic;
+using Silk.NET.Core.Native;
+using Xunit;
+
+namespace Silk.NET.Core.Tests;
+
+public class TestSilkMarshal
+{
+    private readonly List<NativeStringEncoding> encodings = new()
+    {
+        NativeStringEncoding.BStr,
+        NativeStringEncoding.LPStr,
+        NativeStringEncoding.LPTStr,
+        NativeStringEncoding.LPUTF8Str,
+        NativeStringEncoding.LPWStr,
+    };
+    
+    [Fact]
+    public void TestEncodingString()
+    {
+        var input = "Hello world";
+        foreach (var encoding in encodings)
+        {
+            var pointer = SilkMarshal.StringToPtr(input, encoding);
+            var roundTrip = SilkMarshal.PtrToString(pointer, encoding);
+            Assert.Equal(input, roundTrip);
+        }
+    }
+    
+    [Fact]
+    public void TestEncodingStringArray()
+    {
+        var inputs = new List<string>()
+        {
+            "Hello world",
+            "Foo",
+            "Bar",
+            "123",
+        };
+        
+        foreach (var encoding in encodings)
+        {
+            var pointer = SilkMarshal.StringArrayToPtr(inputs, encoding);
+            var roundTrip = SilkMarshal.PtrToStringArray(pointer, inputs.Count, encoding);
+            for (var i = 0; i < roundTrip.Length; i++)
+            {
+                Assert.Equal(inputs[i], roundTrip[i]);
+            }
+        }
+    }
+}

src/Core/Silk.NET.Core/Native/SilkMarshal.cs

@@ -456,7 +456,7 @@ public static unsafe string[] PtrToStringArray
             var ptrs = (nint*) input;
             for (var i = 0; i < numStrings; i++)
             {
-                ret[i] = PtrToString(ptrs![i]);
+                ret[i] = PtrToString(ptrs![i], encoding);
             }
 
             return ret;