Move some intrinsic methods around, reimplement RuneExtensions.Repeat(Rune, Int32)

X10D.Tests/src/Text/RuneTests.cs

@@ -45,6 +45,38 @@ public class RuneTests
         Assert.AreEqual("a", repeated);
     }
 
+    [TestMethod]
+    public void RepeatCodepoint_0000_007F_ShouldCorrect()
+    {
+        string repeated = new Rune(69).Repeat(16);
+        Assert.AreEqual(16, repeated.Length);
+        Assert.AreEqual("EEEEEEEEEEEEEEEE", repeated);
+    }
+
+    [TestMethod]
+    public void RepeatCodepoint_0080_07FF_ShouldCorrect()
+    {
+        string repeated = new Rune(192).Repeat(8);
+        Assert.AreEqual(8, repeated.Length);
+        Assert.AreEqual("ÀÀÀÀÀÀÀÀ", repeated);
+    }
+
+    [TestMethod]
+    public void RepeatCodepoint_0800_FFFF_ShouldCorrect()
+    {
+        string repeated = new Rune(0x0800).Repeat(5);
+        Assert.AreEqual(5, repeated.Length);
+        Assert.AreEqual("ࠀࠀࠀࠀࠀ", repeated);
+    }
+
+    [TestMethod]
+    public void RepeatCodepointBeyondU10000ShouldCorrect()
+    {
+        string repeated = new Rune('\uD800', '\uDC00').Repeat(6);
+        Assert.AreEqual(12, repeated.Length);
+        Assert.AreEqual("𐀀𐀀𐀀𐀀𐀀𐀀", repeated);
+    }
+
     [TestMethod]
     public void RepeatZeroCountShouldBeEmpty()
     {

X10D/Resource.Designer.cs

@@ -19,7 +19,7 @@ namespace X10D {
     // class via a tool like ResGen or Visual Studio.
     // To add or remove a member, edit your .ResX file then rerun ResGen
     // with the /str option, or rebuild your VS project.
-    [global::System.CodeDom.Compiler.GeneratedCodeAttribute("System.Resources.Tools.StronglyTypedResourceBuilder", "16.0.0.0")]
+    [global::System.CodeDom.Compiler.GeneratedCodeAttribute("System.Resources.Tools.StronglyTypedResourceBuilder", "17.0.0.0")]
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute()]
     [global::System.Runtime.CompilerServices.CompilerGeneratedAttribute()]
     internal class Resource {
@@ -77,5 +77,14 @@ namespace X10D {
                 return ResourceManager.GetString("EnumParseNotEnumException", resourceCulture);
             }
         }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to Rune.Utf8SequenceLength returns value outside range 1 to 4 (inclusive), which is unexpected according to the official documentation..
+        /// </summary>
+        internal static string RuneUtf8SequenceLengthUnexpectedValue {
+            get {
+                return ResourceManager.GetString("RuneUtf8SequenceLengthUnexpectedValue", resourceCulture);
+            }
+        }
     }
 }

X10D/Resource.resx

@@ -123,4 +123,7 @@
   <data name="EnumParseNotEnumException" xml:space="preserve">
     <value>Type provided must be an Enum.</value>
   </data>
+  <data name="RuneUtf8SequenceLengthUnexpectedValue" xml:space="preserve">
+    <value>Rune.Utf8SequenceLength returns value outside range 1 to 4 (inclusive), which is unexpected according to the official documentation.</value>
+  </data>
 </root>

X10D/src/Core/IntrinsicExtensions.cs

@@ -1,6 +1,9 @@
 #if NETCOREAPP3_0_OR_GREATER
 
+using System.Diagnostics.Contracts;
+using System.Runtime.CompilerServices;
 using System.Runtime.Intrinsics;
+using System.Runtime.Intrinsics.X86;
 
 namespace X10D.Core;
 
@@ -10,6 +13,154 @@ namespace X10D.Core;
 /// </summary>
 public static class IntrinsicExtensions
 {
-    // Got nothing for now.
+    /// <summary>
+    ///     <para>
+    ///     Correcting <see cref="Vector64{T}"/> of <see langword="byte"/> into 0 and 1 depend on their boolean truthiness.
+    ///     </para>
+    ///     Operation:<br/>
+    ///     <code>
+    ///     for (int i = 0; i &lt; 8; i++) {
+    ///         dest[i] = vector[i] == 0 ? 0 : 1;
+    ///     }
+    ///     </code>
+    /// </summary>
+    /// <param name="vector">Vector of byte to correct.</param>
+    /// <returns>
+    /// A <see cref="Vector64{T}"/> of <see langword="byte"/> which remapped back to 0 and 1 based on boolean truthiness.
+    /// </returns>
+    [Pure]
+    [MethodImpl(MethodImplOptions.AggressiveInlining | MethodImplOptions.AggressiveOptimization)]
+    public static Vector64<byte> CorrectBoolean(this Vector64<byte> vector)
+    {
+        // TODO: AdvSimd implementation.
+        // TODO: WasmSimd implementation. (?)
+
+        var output = IntrinsicUtility.GetUninitializedVector64<byte>();
+
+        for (int i = 0; i < Vector64<byte>.Count; i++)
+        {
+            ref var writeElement = ref Unsafe.Add(ref Unsafe.As<Vector64<byte>, byte>(ref output), i);
+#if NET7_0_OR_GREATER
+            writeElement = vector[i] == 0 ? (byte)0 : (byte)1;
+#else
+            var element = Unsafe.Add(ref Unsafe.As<Vector64<byte>, byte>(ref vector), i);
+            writeElement = element == 0 ? (byte)0 : (byte)1;
+#endif
+        }
+
+        return output;
+    }
+
+    /// <summary>
+    ///     <para>
+    ///     Correcting <see cref="Vector128{T}"/> of <see langword="byte"/> into 0 and 1 depend on their boolean truthiness.
+    ///     </para>
+    ///     Operation:<br/>
+    ///     <code>
+    ///     for (int i = 0; i &lt; 16; i++) {
+    ///         dest[i] = vector[i] == 0 ? 0 : 1;
+    ///     }
+    ///     </code>
+    /// </summary>
+    /// <param name="vector">Vector of byte to correct.</param>
+    /// <returns>
+    /// A <see cref="Vector128{T}"/> of <see langword="byte"/> which remapped back to 0 and 1 based on boolean truthiness.
+    /// </returns>
+    [Pure]
+    [MethodImpl(MethodImplOptions.AggressiveInlining | MethodImplOptions.AggressiveOptimization)]
+    public static Vector128<byte> CorrectBoolean(this Vector128<byte> vector)
+    {
+        if (Sse2.IsSupported)
+        {
+            var cmp = Sse2.CompareEqual(vector, Vector128<byte>.Zero);
+            var result = Sse2.AndNot(cmp, Vector128.Create((byte)1));
+
+            return result;
+        }
+
+        // TODO: AdvSimd implementation.
+        // TODO: WasmSimd implementation.
+
+        var output = IntrinsicUtility.GetUninitializedVector128<byte>();
+
+        for (int i = 0; i < Vector128<byte>.Count; i++)
+        {
+            Unsafe.Add(ref Unsafe.As<Vector128<byte>, byte>(ref output), i) =
+                Unsafe.Add(ref Unsafe.As<Vector128<byte>, byte>(ref vector), i) == 0 ? (byte)0 : (byte)1;
+        }
+
+        return output;
+    }
+
+    /// <summary>
+    ///     <para>
+    ///     Correcting <see cref="Vector256{T}"/> of <see langword="byte"/> into 0 and 1 depend on their boolean truthiness.
+    ///     </para>
+    ///     Operation:<br/>
+    ///     <code>
+    ///     for (int i = 0; i &lt; 32; i++) {
+    ///         dest[i] = vector[i] == 0 ? 0 : 1;
+    ///     }
+    ///     </code>
+    /// </summary>
+    /// <param name="vector">Vector of byte to correct.</param>
+    /// <returns>
+    /// A <see cref="Vector256{T}"/> of <see langword="byte"/> which remapped back to 0 and 1 based on boolean truthiness.
+    /// </returns>
+    [Pure]
+    [MethodImpl(MethodImplOptions.AggressiveInlining | MethodImplOptions.AggressiveOptimization)]
+    public static Vector256<byte> CorrectBoolean(this Vector256<byte> vector)
+    {
+        if (Avx2.IsSupported)
+        {
+            var cmp = Avx2.CompareEqual(vector, Vector256<byte>.Zero);
+            var result = Avx2.AndNot(cmp, Vector256.Create((byte)1));
+
+            return result;
+        }
+
+        var output = IntrinsicUtility.GetUninitializedVector256<byte>();
+
+        for (int i = 0; i < Vector256<byte>.Count; i++)
+        {
+            Unsafe.Add(ref Unsafe.As<Vector256<byte>, byte>(ref output), i) =
+                Unsafe.Add(ref Unsafe.As<Vector256<byte>, byte>(ref vector), i) == 0 ? (byte)0 : (byte)1;
+        }
+
+        return output;
+    }
+
+    /// <summary>
+    ///     <para>
+    ///     Reverse position of 2 64-bit unsigned integer.
+    ///     </para>
+    ///     Operation:<br/>
+    ///     <code>
+    ///     dest[1] = vector[0];
+    ///     dest[0] = vector[1];
+    ///     </code>
+    /// </summary>
+    /// <param name="vector">Input vector.</param>
+    /// <returns>
+    /// A <see cref="Vector128{T}"/> of <see langword="ulong"/> with elements the same as input vector except their positions
+    /// (or indices) are reversed.
+    /// </returns>
+    [Pure]
+    [CLSCompliant(false)]
+    [MethodImpl(MethodImplOptions.AggressiveInlining | MethodImplOptions.AggressiveOptimization)]
+    public static Vector128<ulong> ReverseElements(this Vector128<ulong> vector)
+    {
+        if (Sse2.IsSupported)
+        {
+            return Sse2.Shuffle(vector.AsDouble(), vector.AsDouble(), 0b01).AsUInt64();
+        }
+
+        Vector128<ulong> output = IntrinsicUtility.GetUninitializedVector128<ulong>();
+
+        Unsafe.As<Vector128<ulong>, ulong>(ref output) = Unsafe.Add(ref Unsafe.As<Vector128<ulong>, ulong>(ref vector), 1);
+        Unsafe.Add(ref Unsafe.As<Vector128<ulong>, ulong>(ref output), 1) = Unsafe.As<Vector128<ulong>, ulong>(ref vector);
+
+        return output;
+    }
 }
 #endif

X10D/src/Core/IntrinsicUtility.cs

@@ -14,149 +14,14 @@ namespace X10D.Core;
 public static class IntrinsicUtility
 {
     // NOTE:
-    // ANY METHOD THAT OPERATE ON ANYTHING THAT ISN'T FLOAT IS NOT SSE COMPATIBLE, MUST BE SSE2 AND BEYOND VERSION
+    // ANY METHOD THAT OPERATE ON ANYTHING THAT ISN'T FLOAT IS NOT SSE COMPATIBLE, MUST BE SSE2 AND BEYONDS
     // FOR API CONSISTENCY.
 
     /// <summary>
-    ///     <br>
+    ///     <para>
-    ///     Correcting <see cref="Vector64{T}"/> of <see langword="byte"/> into 0 and 1 depend on their boolean truthiness.
-    ///     </br>
-    ///     <br>Operation (raw):</br>
-    ///     <code>
-    ///     for (int i = 0; i &lt; 8; i++) {
-    ///         dest[i] = ~(vector[i] == 0 ? 0xFF : 0x00) &amp; 1;
-    ///     }
-    ///     </code>
-    ///     <br>Operation (simplified):</br>
-    ///     <code>
-    ///     for (int i = 0; i &lt; 8; i++) {
-    ///         dest[i] = vector[i] == 0 ? 0 : 1;
-    ///     }
-    ///     </code>
-    /// </summary>
-    /// <param name="vector">Vector of byte to correct.</param>
-    /// <returns>
-    /// A <see cref="Vector64{T}"/> of <see langword="byte"/> which remapped back to 0 and 1 based on boolean truthiness.
-    /// </returns>
-    [Pure]
-    [MethodImpl(MethodImplOptions.AggressiveInlining | MethodImplOptions.AggressiveOptimization)]
-    public static Vector64<byte> CorrectBoolean(Vector64<byte> vector)
-    {
-        // TODO: AdvSimd implementation.
-        // TODO: WasmSimd implementation. (?)
-
-        var output = GetUninitializedVector64<byte>();
-
-        for (int i = 0; i < Vector64<byte>.Count; i++)
-        {
-            ref var writeElement = ref Unsafe.Add(ref Unsafe.As<Vector64<byte>, byte>(ref output), i);
-#if NET7_0_OR_GREATER
-            writeElement = vector[i] == 0 ? (byte)0 : (byte)1;
-#else
-            var element = Unsafe.Add(ref Unsafe.As<Vector64<byte>, byte>(ref vector), i);
-            writeElement = element == 0 ? (byte)0 : (byte)1;
-#endif
-        }
-
-        return output;
-    }
-
-    /// <summary>
-    ///     <br>
-    ///     Correcting <see cref="Vector128{T}"/> of <see langword="byte"/> into 0 and 1 depend on their boolean truthiness.
-    ///     </br>
-    ///     <br>Operation (raw):</br>
-    ///     <code>
-    ///     for (int i = 0; i &lt; 16; i++) {
-    ///         dest[i] = ~(vector[i] == 0 ? 0xFF : 0x00) &amp; 1;
-    ///     }
-    ///     </code>
-    ///     <br>Operation (simplified):</br>
-    ///     <code>
-    ///     for (int i = 0; i &lt; 16; i++) {
-    ///         dest[i] = vector[i] == 0 ? 0 : 1;
-    ///     }
-    ///     </code>
-    /// </summary>
-    /// <param name="vector">Vector of byte to correct.</param>
-    /// <returns>
-    /// A <see cref="Vector128{T}"/> of <see langword="byte"/> which remapped back to 0 and 1 based on boolean truthiness.
-    /// </returns>
-    [Pure]
-    [MethodImpl(MethodImplOptions.AggressiveInlining | MethodImplOptions.AggressiveOptimization)]
-    public static Vector128<byte> CorrectBoolean(Vector128<byte> vector)
-    {
-        if (Sse2.IsSupported)
-        {
-            var cmp = Sse2.CompareEqual(vector, Vector128<byte>.Zero);
-            var result = Sse2.AndNot(cmp, Vector128.Create((byte)1));
-
-            return result;
-        }
-
-        // TODO: AdvSimd implementation.
-        // TODO: WasmSimd implementation.
-
-        var output = GetUninitializedVector128<byte>();
-
-        for (int i = 0; i < Vector128<byte>.Count; i++)
-        {
-            Unsafe.Add(ref Unsafe.As<Vector128<byte>, byte>(ref output), i) =
-                Unsafe.Add(ref Unsafe.As<Vector128<byte>, byte>(ref vector), i) == 0 ? (byte)0 : (byte)1;
-        }
-
-        return output;
-    }
-
-    /// <summary>
-    ///     <br>
-    ///     Correcting <see cref="Vector256{T}"/> of <see langword="byte"/> into 0 and 1 depend on their boolean truthiness.
-    ///     </br>
-    ///     <br>Operation (raw):</br>
-    ///     <code>
-    ///     for (int i = 0; i &lt; 16; i++) {
-    ///         dest[i] = ~(vector[i] == 0 ? 0xFF : 0x00) &amp; 1;
-    ///     }
-    ///     </code>
-    ///     <br>Operation (simplified):</br>
-    ///     <code>
-    ///     for (int i = 0; i &lt; 16; i++) {
-    ///         dest[i] = vector[i] == 0 ? 0 : 1;
-    ///     }
-    ///     </code>
-    /// </summary>
-    /// <param name="vector">Vector of byte to correct.</param>
-    /// <returns>
-    /// A <see cref="Vector256{T}"/> of <see langword="byte"/> which remapped back to 0 and 1 based on boolean truthiness.
-    /// </returns>
-    [Pure]
-    [MethodImpl(MethodImplOptions.AggressiveInlining | MethodImplOptions.AggressiveOptimization)]
-    public static Vector256<byte> CorrectBoolean(Vector256<byte> vector)
-    {
-        if (Avx2.IsSupported)
-        {
-            var cmp = Avx2.CompareEqual(vector, Vector256<byte>.Zero);
-            var result = Avx2.AndNot(cmp, Vector256.Create((byte)1));
-
-            return result;
-        }
-
-        var output = GetUninitializedVector256<byte>();
-
-        for (int i = 0; i < Vector256<byte>.Count; i++)
-        {
-            Unsafe.Add(ref Unsafe.As<Vector256<byte>, byte>(ref output), i) =
-                Unsafe.Add(ref Unsafe.As<Vector256<byte>, byte>(ref vector), i) == 0 ? (byte)0 : (byte)1;
-        }
-
-        return output;
-    }
-
-    /// <summary>
-    ///     <br>
     ///     Multiply packed 64-bit unsigned integer elements in a and b and truncate the results to 64-bit integer.
-    ///     </br>
+    ///     </para>
-    ///     <br>Operation:</br>
+    ///     Operation:<br/>
     ///     <code>
     ///     dest[0] = lhs[0] * rhs[0];
     ///     dest[1] = lhs[1] * rhs[1];
@@ -203,10 +68,10 @@ public static class IntrinsicUtility
     }
 
     /// <summary>
-    ///     <br>
+    ///     <para>
     ///     Multiply packed 64-bit unsigned integer elements in a and b and truncate the results to 64-bit integer.
-    ///     </br>
+    ///     </para>
-    ///     <br>Operation:</br>
+    ///     Operation:<br/>
     ///     <code>
     ///     dest[0] = lhs[0] * rhs[0];
     ///     dest[1] = lhs[1] * rhs[1];
@@ -252,10 +117,10 @@ public static class IntrinsicUtility
     }
 
     /// <summary>
-    ///     <br>
+    ///     <para>
     ///     Multiply packed 64-bit signed integer elements in a and b and truncate the results to 64-bit integer.
-    ///     </br>
+    ///     </para>
-    ///     <br>Operation:</br>
+    ///     Operation:<br/>
     ///     <code>
     ///     dest[0] = lhs[0] * rhs[0];
     ///     dest[1] = lhs[1] * rhs[1];
@@ -274,10 +139,10 @@ public static class IntrinsicUtility
     }
 
     /// <summary>
-    ///     <br>
+    ///     <para>
     ///     Multiply packed 64-bit signed integer elements in a and b and truncate the results to 64-bit integer.
-    ///     </br>
+    ///     </para>
-    ///     <br>Operation:</br>
+    ///     Operation:<br/>
     ///     <code>
     ///     dest[0] = lhs[0] * rhs[0];
     ///     dest[1] = lhs[1] * rhs[1];
@@ -298,11 +163,11 @@ public static class IntrinsicUtility
     }
 
     /// <summary>
-    ///     <br>
+    ///     <para>
     ///     Horizontally apply OR operation on adjacent pairs of single-precision (32-bit) floating-point elements in lhs and
     ///     rhs.
-    ///     </br>
+    ///     </para>
-    ///     <br>Operation:</br>
+    ///     Operation:<br/>
     ///     <code>
     ///     dest[0] = lhs[0] | lhs[1];
     ///     dest[1] = lhs[2] | lhs[3];
@@ -353,10 +218,10 @@ public static class IntrinsicUtility
     }
 
     /// <summary>
-    ///     <br>
+    ///     <para>
     ///     Horizontally apply OR operation on adjacent pairs of 32-bit integer elements in lhs and rhs.
-    ///     </br>
+    ///     </para>
-    ///     <br>Operation:</br>
+    ///     Operation:<br/>
     ///     <code>
     ///     dest[0] = lhs[0] | lhs[1];
     ///     dest[1] = lhs[2] | lhs[3];
@@ -378,10 +243,10 @@ public static class IntrinsicUtility
     }
 
     /// <summary>
-    ///     <br>
+    ///     <para>
     ///     Horizontally apply OR operation on adjacent pairs of 32-bit unsigned integer elements in lhs and rhs.
-    ///     </br>
+    ///     </para>
-    ///     <br>Operation:</br>
+    ///     Operation:<br/>
     ///     <code>
     ///     dest[0] = lhs[0] | lhs[1];
     ///     dest[1] = lhs[2] | lhs[3];
@@ -403,41 +268,9 @@ public static class IntrinsicUtility
         return HorizontalOr(lhs.AsSingle(), rhs.AsSingle()).AsUInt32();
     }
 
-    /// <summary>
-    ///     <br>Reverse position of 2 64-bit unsigned integer.</br>
-    ///     <br>Operation:</br>
-    ///     <code>
-    ///     ulong tmp = vector[0];
-    ///     vector[0] = vector[1];
-    ///     vector[1] = tmp;
-    ///     </code>
-    /// </summary>
-    /// <param name="vector">Input vector.</param>
-    /// <returns>
-    /// A <see cref="Vector128{T}"/> of <see langword="ulong"/> with elements the same as input vector except their positions
-    /// (or indices) are reversed.
-    /// </returns>
-    [Pure]
-    [CLSCompliant(false)]
-    [MethodImpl(MethodImplOptions.AggressiveInlining | MethodImplOptions.AggressiveOptimization)]
-    public static Vector128<ulong> ReverseElements(Vector128<ulong> vector)
-    {
-        if (Sse2.IsSupported)
-        {
-            return Sse2.Shuffle(vector.AsDouble(), vector.AsDouble(), 0b01).AsUInt64();
-        }
-
-        Vector128<ulong> output = GetUninitializedVector128<ulong>();
-
-        Unsafe.As<Vector128<ulong>, ulong>(ref output) = Unsafe.Add(ref Unsafe.As<Vector128<ulong>, ulong>(ref vector), 1);
-        Unsafe.Add(ref Unsafe.As<Vector128<ulong>, ulong>(ref output), 1) = Unsafe.As<Vector128<ulong>, ulong>(ref vector);
-
-        return output;
-    }
-
     // Helper methods
     [MethodImpl(MethodImplOptions.AggressiveInlining | MethodImplOptions.AggressiveOptimization)]
-    private static Vector64<T> GetUninitializedVector64<T>() where T : struct
+    internal static Vector64<T> GetUninitializedVector64<T>() where T : struct
     {
 #if NET6_0_OR_GREATER
         Unsafe.SkipInit(out Vector64<T> output);
@@ -448,7 +281,7 @@ public static class IntrinsicUtility
     }
 
     [MethodImpl(MethodImplOptions.AggressiveInlining | MethodImplOptions.AggressiveOptimization)]
-    private static Vector128<T> GetUninitializedVector128<T>() where T : struct
+    internal static Vector128<T> GetUninitializedVector128<T>() where T : struct
     {
 #if NET6_0_OR_GREATER
         Unsafe.SkipInit(out Vector128<T> output);
@@ -459,7 +292,7 @@ public static class IntrinsicUtility
     }
 
     [MethodImpl(MethodImplOptions.AggressiveInlining | MethodImplOptions.AggressiveOptimization)]
-    private static Vector256<T> GetUninitializedVector256<T>() where T : struct
+    internal static Vector256<T> GetUninitializedVector256<T>() where T : struct
     {
 #if NET6_0_OR_GREATER
         Unsafe.SkipInit(out Vector256<T> output);

X10D/src/Core/SpanExtensions.cs

@@ -173,9 +173,8 @@ public static class SpanExtensions
                     if (Sse2.IsSupported)
                     {
                         var load = Sse2.LoadScalarVector128((ulong*)pSource).AsByte();
-                        var correct = IntrinsicUtility.CorrectBoolean(load);
 
-                        return unchecked((byte)(IntegerPackingMagic * correct.AsUInt64().GetElement(0) >> 56));
+                        return unchecked((byte)(IntegerPackingMagic * load.CorrectBoolean().AsUInt64().GetElement(0) >> 56));
                     }
 
                     // Probably should remove this piece of code because it is untested, but I see no reason why it should fail
@@ -185,15 +184,12 @@ public static class SpanExtensions
                     {
                         // Hasn't been tested since March 6th 2023 (Reason: Unavailable hardware).
                         var load = AdvSimd.LoadVector64((byte*)pSource);
-                        var correct = IntrinsicUtility.CorrectBoolean(load);
 
-                        return unchecked((byte)(IntegerPackingMagic * correct.AsUInt64().GetElement(0) >> 56));
+                        return unchecked((byte)(IntegerPackingMagic * load.CorrectBoolean().AsUInt64().GetElement(0) >> 56));
                     }
-                    else
+
-                    {
                     goto default;
                 }
-                }
 #endif
             default:
                 byte result = 0;
@@ -252,10 +248,10 @@ public static class SpanExtensions
                 {
                     fixed (bool* pSource = source)
                     {
-                        var load = Sse2.LoadVector128((byte*)pSource);
+                        Vector128<byte> load = Sse2.LoadVector128((byte*)pSource);
-                        var correct = IntrinsicUtility.CorrectBoolean(load).AsUInt64();
+                        Vector128<ulong> correct = load.CorrectBoolean().AsUInt64();
-                        var multiply = IntrinsicUtility.Multiply(IntegerPackingMagicV128, correct);
+                        Vector128<ulong> multiply = IntrinsicUtility.Multiply(IntegerPackingMagicV128, correct);
-                        var shift = Sse2.ShiftRightLogical(multiply, 56);
+                        Vector128<ulong> shift = Sse2.ShiftRightLogical(multiply, 56);
 
                         return (short)(shift.GetElement(0) | (shift.GetElement(1) << 8));
                     }
@@ -319,52 +315,52 @@ public static class SpanExtensions
                 {
                     if (Avx2.IsSupported)
                     {
-                        var load = Avx.LoadVector256((byte*)pSource);
+                        Vector256<byte> load = Avx.LoadVector256((byte*)pSource);
-                        var correct = IntrinsicUtility.CorrectBoolean(load).AsUInt64();
+                        Vector256<ulong> correct = load.CorrectBoolean().AsUInt64();
 
-                        var multiply = IntrinsicUtility.Multiply(IntegerPackingMagicV256, correct);
+                        Vector256<ulong> multiply = IntrinsicUtility.Multiply(IntegerPackingMagicV256, correct);
-                        var shift = Avx2.ShiftRightLogical(multiply, 56);
+                        Vector256<ulong> shift = Avx2.ShiftRightLogical(multiply, 56);
                         shift = Avx2.ShiftLeftLogicalVariable(shift, Vector256.Create(0UL, 8, 16, 24));
 
-                        var p1 = Avx2.Permute4x64(shift, 0b10_11_00_01);
+                        Vector256<ulong> p1 = Avx2.Permute4x64(shift, 0b10_11_00_01);
-                        var or1 = Avx2.Or(shift, p1);
+                        Vector256<ulong> or1 = Avx2.Or(shift, p1);
-                        var p2 = Avx2.Permute4x64(or1, 0b00_00_10_10);
+                        Vector256<ulong> p2 = Avx2.Permute4x64(or1, 0b00_00_10_10);
-                        var or2 = Avx2.Or(or1, p2);
+                        Vector256<ulong> or2 = Avx2.Or(or1, p2);
 
                         return (int)or2.GetElement(0);
                     }
                     if (Sse2.IsSupported)
                     {
-                        var load = Sse2.LoadVector128((byte*)pSource);
+                        Vector128<byte> load = Sse2.LoadVector128((byte*)pSource);
-                        var correct = IntrinsicUtility.CorrectBoolean(load).AsUInt64();
+                        Vector128<ulong> correct = load.CorrectBoolean().AsUInt64();
 
-                        var multiply = IntrinsicUtility.Multiply(IntegerPackingMagicV128, correct);
+                        Vector128<ulong> multiply = IntrinsicUtility.Multiply(IntegerPackingMagicV128, correct);
-                        var shift1 = Sse2.ShiftRightLogical(multiply, 56);
+                        Vector128<ulong> shift1 = Sse2.ShiftRightLogical(multiply, 56);
                         shift1 = Sse2.ShiftLeftLogical(shift1, Vector128.Create(0UL, 8UL));
 
                         load = Sse2.LoadVector128((byte*)(pSource + 16));
-                        correct = IntrinsicUtility.CorrectBoolean(load).AsUInt64();
+                        correct = load.CorrectBoolean().AsUInt64();
 
                         multiply = IntrinsicUtility.Multiply(IntegerPackingMagicV128, correct);
-                        var shift2 = Sse2.ShiftRightLogical(multiply, 56);
+                        Vector128<ulong> shift2 = Sse2.ShiftRightLogical(multiply, 56);
                         shift2 = Sse2.ShiftLeftLogical(shift2, Vector128.Create(16UL, 24UL));
 
-                        var or1 = Sse2.Or(shift1, shift2);
+                        Vector128<ulong> or1 = Sse2.Or(shift1, shift2);
-                        var or2 = Sse2.Or(or1, IntrinsicUtility.ReverseElements(or1));
+                        Vector128<ulong> or2 = Sse2.Or(or1, or1.ReverseElements());
 
                         return (int)or2.GetElement(0);
                     }
                     if (AdvSimd.IsSupported)
                     {
                         // Hasn't been tested since March 6th 2023 (Reason: Unavailable hardware).
-                        var vector1 = IntrinsicUtility.CorrectBoolean(AdvSimd.LoadVector128((byte*)pSource)).AsUInt64();
+                        Vector128<ulong> vector1 = AdvSimd.LoadVector128((byte*)pSource).CorrectBoolean().AsUInt64();
-                        var vector2 = IntrinsicUtility.CorrectBoolean(AdvSimd.LoadVector128((byte*)(pSource + 16))).AsUInt64();
+                        Vector128<ulong> vector2 = AdvSimd.LoadVector128((byte*)(pSource + 16)).CorrectBoolean().AsUInt64();
 
-                        var calc1 = AdvSimd.ShiftRightLogical(IntrinsicUtility.Multiply(IntegerPackingMagicV128, vector1), 56);
+                        Vector128<ulong> calc1 = AdvSimd.ShiftRightLogical(IntrinsicUtility.Multiply(IntegerPackingMagicV128, vector1), 56);
-                        var calc2 = AdvSimd.ShiftRightLogical(IntrinsicUtility.Multiply(IntegerPackingMagicV128, vector2), 56);
+                        Vector128<ulong> calc2 = AdvSimd.ShiftRightLogical(IntrinsicUtility.Multiply(IntegerPackingMagicV128, vector2), 56);
 
-                        var shift1 = AdvSimd.ShiftLogical(calc1, Vector128.Create(0, 8));
+                        Vector128<ulong> shift1 = AdvSimd.ShiftLogical(calc1, Vector128.Create(0, 8));
-                        var shift2 = AdvSimd.ShiftLogical(calc2, Vector128.Create(16, 24));
+                        Vector128<ulong> shift2 = AdvSimd.ShiftLogical(calc2, Vector128.Create(16, 24));
 
                         return (int)(shift1.GetElement(0) | shift1.GetElement(1) | shift2.GetElement(0) | shift2.GetElement(1));
                     }

X10D/src/Text/RuneExtensions.cs

@@ -1,5 +1,5 @@
 #if NETCOREAPP3_0_OR_GREATER
-using System;
+using System.Diagnostics;
 using System.Diagnostics.Contracts;
 using System.Runtime.CompilerServices;
 using System.Runtime.InteropServices;
@@ -47,40 +47,58 @@ public static class RuneExtensions
         }
 
         // Helpful documentation: https://en.wikipedia.org/wiki/UTF-8
+        // This probably gonna break interning but whatever.
         switch (value.Utf8SequenceLength)
         {
             case 1:
                 {
-                    Unsafe.SkipInit(out byte bytes);
+                    // Codepoint 0 to 0x00FF can be directly turn into char value without any conversion.
-                    value.EncodeToUtf8(MemoryMarshal.CreateSpan(ref bytes, 1));
-
                     return new string((char)value.Value, count);
                 }
 
+            // Codepoint 0x0080 to 0x07FF takes 2 UTF-8 bytes, and it can be represented by 1 UTF-16 character (.NET runtime use
+            // UTF-16 encoding).
+            // Source: https://stackoverflow.com/questions/63905684
             case 2:
+            // Codepoint 0x0800 to 0xFFFF takes 3 UTF-8 bytes, and can also be represented by 1 UTF-16 character.
+            case 3:
                 {
-                    Span<byte> bytes = stackalloc byte[2];
+                    // Codepoint 0x0080 to 0x07FF convert into 1 .NET character string, directly use string constructor.
+                    unsafe
+                    {
+                        Span<byte> bytes = stackalloc byte[value.Utf8SequenceLength];
                         value.EncodeToUtf8(bytes);
 
-                    return new string(Encoding.UTF8.GetString(bytes)[0], count);
+                        char character;
+                        Encoding.UTF8.GetChars(bytes, new Span<char>(&character, 1));
+
+                        return new string(character, count);
+                    }
+                }
+
+            // Codepoint 0x10000 and beyond will takes **only** 2 UTF-16 character.
+            case 4:
+                {
+                    return string.Create(count * 2, value, (span, rune) =>
+                    {
+                        unsafe {
+                            Span<byte> bytes = stackalloc byte[4];
+                            value.EncodeToUtf8(bytes);
+
+                            int characters; // 2 characters, fit inside 1 32-bit integer.
+                            Encoding.UTF8.GetChars(bytes, new Span<char>(&characters, 2));
+
+                            MemoryMarshal.Cast<char, int>(span).Fill(characters);
+                        }
+                    });
                 }
 
             default:
-                {
+#if NET7_0_OR_GREATER
-                    int utf8SequenceLength = value.Utf8SequenceLength;
+                throw new UnreachableException(Resource.RuneUtf8SequenceLengthUnexpectedValue);
-                    Span<byte> utf8 = stackalloc byte[utf8SequenceLength];
+#else
-                    value.EncodeToUtf8(utf8);
+                throw new InvalidOperationException(Resource.RuneUtf8SequenceLengthUnexpectedValue);
-
+#endif
-                    // Limit to maximum 1024 bytes stack allocation (Rune.Utf8SequenceLength return value in range of [1; 4])
-                    Span<byte> buffer = count <= 256 ? stackalloc byte[utf8.Length * count] : new byte[utf8.Length * count];
-
-                    for (var index = 0; index < count; index++)
-                    {
-                        utf8.CopyTo(buffer.Slice(index * utf8.Length, utf8.Length));
-                    }
-
-                    return Encoding.UTF8.GetString(buffer);
-                }
         }
     }
 }