CollectionsExtensions.{AddRange,InsertRange,CopyTo,AsReadOnly}

Author: Windows10CE

src/MonoMod.Backports.Shims/MonoMod.Backports.Shims.csproj

@@ -1,4 +1,4 @@
-<Project Sdk="Microsoft.Build.NoTargets">
+<Project Sdk="Microsoft.Build.NoTargets">
 
   <PropertyGroup>
     <IsPackable>true</IsPackable>
@@ -18,6 +18,10 @@
     <PackInference Remove="@(PackInference)" />
   </ItemGroup>
 
+  <ItemDefinitionGroup>
+    <ExtraShimPackageVersion Visible="false" />
+  </ItemDefinitionGroup>
+
   <!-- Packages we're going to shim -->
   <ItemGroup>
     <PackageReference Include="Microsoft.Bcl.HashCode" Version="6.0.0" Shim="true" />

src/MonoMod.Backports/MonoMod.Backports.csproj

@@ -1,4 +1,4 @@
-<Project Sdk="Microsoft.NET.Sdk">
+<Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
     <!-- target frameworks are defined in Common.props -->

src/MonoMod.Backports/System/Collections/Generic/CollectionExtensionsEx.cs

@@ -0,0 +1,100 @@
+#if NET8_0_OR_GREATER
+#define HAS_LISTSPANMETHODS
+#endif
+#if NET7_0_OR_GREATER
+#define HAS_ASREADONLY
+#endif
+
+using System.Collections.ObjectModel;
+using System.Diagnostics.CodeAnalysis;
+#if !HAS_LISTSPANMETHODS
+using System.Runtime.InteropServices;
+#endif
+
+namespace System.Collections.Generic
+{
+    [SuppressMessage("Design", "CA1002:Do not expose generic lists",
+        Justification = "Replicating existing APIs")]
+    public static class CollectionExtensionsEx
+    {
+        public static void AddRange<T>(
+#if !HAS_LISTSPANMETHODS
+            this
+#endif
+                List<T> list, params ReadOnlySpan<T> source
+        )
+        {
+#if HAS_LISTSPANMETHODS
+            list.AddRange(source);
+#else
+            ThrowHelper.ThrowIfArgumentNull(list, ExceptionArgument.list);
+            if (source.IsEmpty)
+            {
+                return;
+            }
+            var currentCount = list.Count;
+            CollectionsMarshal.SetCount(list, currentCount + source.Length);
+            source.CopyTo(CollectionsMarshal.AsSpan(list).Slice(currentCount + 1));
+#endif
+        }
+        
+        public static void InsertRange<T>(
+#if !HAS_LISTSPANMETHODS
+            this
+#endif
+                List<T> list, int index, params ReadOnlySpan<T> source
+        )
+        {
+#if HAS_LISTSPANMETHODS
+            list.InsertRange(index, source);
+#else
+            ThrowHelper.ThrowIfArgumentNull(list, ExceptionArgument.list);
+            if ((uint)index > (uint)list.Count)
+            {
+                ThrowHelper.ThrowArgumentOutOfRangeException(ExceptionArgument.index);
+            }
+            if (source.IsEmpty)
+            {
+                return;
+            }
+            var currentCount = list.Count;
+            CollectionsMarshal.SetCount(list, currentCount + source.Length);
+            var items = CollectionsMarshal.AsSpan(list);
+            if (index < currentCount)
+            {
+                items.Slice(index, currentCount - index).CopyTo(items.Slice(index + source.Length));
+            }
+            source.CopyTo(items.Slice(index));
+#endif
+        }
+        
+        public static void CopyTo<T>(
+#if !HAS_LISTSPANMETHODS
+            this
+#endif
+                List<T> list, Span<T> destination
+        )
+        {
+#if HAS_LISTSPANMETHODS
+            list.CopyTo(destination);
+#else
+            ThrowHelper.ThrowIfArgumentNull(list, ExceptionArgument.list);
+            CollectionsMarshal.AsSpan(list).CopyTo(destination);
+#endif
+        }
+
+        public static ReadOnlyCollection<T> AsReadOnly<T>(
+#if !HAS_ASREADONLY
+            this
+#endif
+                IList<T> list
+            ) => new(list);
+        
+        public static ReadOnlyDictionary<TKey, TValue> AsReadOnly<TKey, TValue>(
+#if !HAS_ASREADONLY
+            this
+#endif
+                IDictionary<TKey, TValue> list
+        ) where TKey : notnull => new(list);
+    }
+}

src/MonoMod.Backports/System/Collections/ObjectModel/ReadOnlyDictionary,gte_fx_4.5,is_core,is_std.cs

@@ -0,0 +1,4 @@
+using System.Collections.ObjectModel;
+using System.Runtime.CompilerServices;
+
+[assembly: TypeForwardedTo(typeof(ReadOnlyDictionary<,>))]