Add ImmutableArrayExtensions class

Ramstack.Structures.Tests/Collections/ArrayViewTests.cs

@@ -1,3 +1,4 @@
+using System.Collections.Immutable;
 using System.Diagnostics.CodeAnalysis;
 using System.Runtime.CompilerServices;
 
@@ -417,9 +418,15 @@ public void IndexOf()
     public void AsView(string? value)
     {
         var list = value?.ToCharArray();
+        var immutable = value.AsSpan().ToImmutableArray();
+
         Assert.That(
             list.AsView(),
             Is.EquivalentTo(value.AsSpan().ToArray()));
+
+        Assert.That(
+            immutable.AsView(),
+            Is.EquivalentTo(value.AsSpan().ToArray()));
     }
 
     [TestCase(null, 0)]
@@ -432,10 +439,15 @@ public void AsView(string? value)
     public void AsView_Index(string? value, int index)
     {
         var list = value?.ToCharArray();
+        var immutable = value.AsSpan().ToImmutableArray();
 
         Assert.That(
             list.AsView(index),
             Is.EquivalentTo(value.AsSpan(index).ToArray()));
+
+        Assert.That(
+            immutable.AsView(index),
+            Is.EquivalentTo(value.AsSpan(index).ToArray()));
     }
 
     [TestCase(null, 0, 0)]
@@ -449,10 +461,15 @@ public void AsView_Index(string? value, int index)
     public void AsView_Range(string? value, int index, int length)
     {
         var list = value?.ToCharArray();
+        var immutable = value.AsSpan().ToImmutableArray();
 
         Assert.That(
             list.AsView(index, length),
             Is.EquivalentTo(value.AsSpan(index, length).ToArray()));
+
+        Assert.That(
+            immutable.AsView(index, length),
+            Is.EquivalentTo(value.AsSpan(index, length).ToArray()));
     }
 
     [TestCase(null, 1)]
@@ -462,10 +479,15 @@ public void AsView_Range(string? value, int index, int length)
     public void AsView_InvalidIndex_ShouldThrow(string? value, int index)
     {
         var list = value?.ToCharArray();
+        var immutable = value.AsSpan().ToImmutableArray();
 
         Assert.That(
             () => list.AsView(index),
             Throws.TypeOf<ArgumentOutOfRangeException>());
+
+        Assert.That(
+            () => immutable.AsView(index),
+            Throws.TypeOf<ArgumentOutOfRangeException>());
     }
 
     [TestCase(null, 1, 0)]
@@ -479,9 +501,14 @@ public void AsView_InvalidIndex_ShouldThrow(string? value, int index)
     public void AsView_InvalidRange_ShouldThrow(string? value, int index, int length)
     {
         var list = value?.ToCharArray();
+        var immutable = value.AsSpan().ToImmutableArray();
 
         Assert.That(
             () => list.AsView(index, length),
             Throws.TypeOf<ArgumentOutOfRangeException>());
+
+        Assert.That(
+            () => immutable.AsView(index, length),
+            Throws.TypeOf<ArgumentOutOfRangeException>());
     }
 }

Ramstack.Structures/Collections/ArrayViewExtensions.cs

@@ -22,7 +22,7 @@ public static ArrayView<T> AsView<T>(this T[]? value) =>
     /// Creates a new <see cref="ArrayView{T}"/> over a portion of the target array from a specified position to the end of the array.
     /// </summary>
     /// <param name="value">The target array.</param>
-    /// <param name="index">The index at which to begin this slice.</param>
+    /// <param name="index">The index at which to begin the array view.</param>
     /// <returns>
     /// An <see cref="ArrayView{T}"/> representing the array.
     /// </returns>
@@ -34,14 +34,14 @@ public static ArrayView<T> AsView<T>(this T[]? value, int index) =>
     /// Creates a new <see cref="ArrayView{T}"/> over a portion of the target array from a specified position for a specified number of elements.
     /// </summary>
     /// <param name="value">The target array.</param>
-    /// <param name="index">The index at which to begin this slice.</param>
-    /// <param name="length">The desired length for the slice.</param>
+    /// <param name="index">The index at which to begin the array view.</param>
+    /// <param name="count">The number of items in the array view.</param>
     /// <returns>
     /// An <see cref="ArrayView{T}"/> representing the array.
     /// </returns>
     [MethodImpl(MethodImplOptions.AggressiveInlining)]
-    public static ArrayView<T> AsView<T>(this T[]? value, int index, int length) =>
-        new(value ?? [], index, length);
+    public static ArrayView<T> AsView<T>(this T[]? value, int index, int count) =>
+        new(value ?? [], index, count);
 
     /// <summary>
     /// Finds the index of the first occurrence of a specified value in this instance.

Ramstack.Structures/Collections/ImmutableArrayExtensions.cs

@@ -0,0 +1,43 @@
+using System.Collections.Immutable;
+using System.Runtime.InteropServices;
+
+namespace Ramstack.Collections;
+
+/// <summary>
+/// Provides extension methods for the <see cref="ImmutableArray{T}"/> structure.
+/// </summary>
+public static class ImmutableArrayExtensions
+{
+    /// <summary>
+    /// Creates an <see cref="ArrayView{T}"/> over an immutable array.
+    /// </summary>
+    /// <param name="value">The immutable array to wrap.</param>
+    /// <returns>
+    /// The read-only view of the array.
+    /// </returns>
+    public static ArrayView<T> AsView<T>(this ImmutableArray<T> value) =>
+        ImmutableCollectionsMarshal.AsArray(value).AsView();
+
+    /// <summary>
+    /// Creates an <see cref="ArrayView{T}"/> over an immutable array starting at a specified position to the end of the array.
+    /// </summary>
+    /// <param name="value">The immutable array to wrap.</param>
+    /// <param name="index">The index at which to begin the array view.</param>
+    /// <returns>
+    /// The read-only view of the array.
+    /// </returns>
+    public static ArrayView<T> AsView<T>(this ImmutableArray<T> value, int index) =>
+        ImmutableCollectionsMarshal.AsArray(value).AsView(index);
+
+    /// <summary>
+    /// Creates an <see cref="ArrayView{T}"/> over an immutable array starting at a specified position for a specified length.
+    /// </summary>
+    /// <param name="value">The immutable array to wrap.</param>
+    /// <param name="index">The index at which to begin the array view.</param>
+    /// <param name="count">The number of items in the array view.</param>
+    /// <returns>
+    /// The read-only view of the array.
+    /// </returns>
+    public static ArrayView<T> AsView<T>(this ImmutableArray<T> value, int index, int count) =>
+        ImmutableCollectionsMarshal.AsArray(value).AsView(index, count);
+}