speed up for xor

GeometryDashAPI.Benchmarks/Benchmarks/XorBenchmark.cs

@@ -0,0 +1,30 @@
+using System;
+using System.Linq;
+using BenchmarkDotNet.Attributes;
+
+namespace GeometryDashAPI.Benchmarks.Benchmarks;
+
+[MemoryDiagnoser]
+public class XorBenchmark
+{
+    private static Random random = new(123);
+    private byte[] array = Enumerable.Range(0, 1000).Select(x => (byte)random.Next(byte.MaxValue)).ToArray();
+
+    [Benchmark]
+    public void SimdXor()
+    {
+        Crypt.InlineXor(array, 11);
+    }
+
+    [Benchmark]
+    public void NaiveXor()
+    {
+        Crypt.NaiveXor(array, 11);
+    }
+
+    [Benchmark]
+    public byte[] OldXor()
+    {
+        return Crypt.XOR(array, 11);
+    }
+}

GeometryDashAPI.Tests/CryptTests.cs

@@ -0,0 +1,23 @@
+using System;
+using System.Linq;
+using FluentAssertions;
+using NUnit.Framework;
+
+namespace GeometryDashAPI.Tests;
+
+[TestFixture]
+public class CryptTests
+{
+    [Test]
+    public void InlineXor()
+    {
+        var random = new Random(123);
+        var data = Enumerable.Range(0, 100).Select(_ => (byte)random.Next(byte.MaxValue)).ToArray();
+        var expected = (byte[])data.Clone();
+
+        Crypt.NaiveXor(expected, 11);
+        Crypt.InlineXor(data.AsSpan(), 11);
+
+        data.Should().BeEquivalentTo(expected);
+    }
+}

GeometryDashAPI/Crypt.cs

@@ -1,6 +1,7 @@
 using System;
 using System.IO;
 using System.IO.Compression;
+using System.Numerics;
 using System.Text;
 using ICSharpCode.SharpZipLib.Zip.Compression.Streams;
 
@@ -16,12 +17,32 @@ public static byte[] XOR(byte[] data, int key)
             return result;
         }
 
-        public static void InlineXor(Span<byte> data, int key)
+        public static void NaiveXor(Span<byte> data, byte key)
         {
             for (var i = 0; i < data.Length; i++)
                 data[i] = (byte)(data[i] ^ key);
         }
 
+        public static void InlineXor(Span<byte> data, byte key)
+        {
+#if NET6_0_OR_GREATER
+            var startIndex = 0;
+            var vKey = new Vector<byte>(key);
+            while (startIndex + Vector<byte>.Count < data.Length)
+            {
+                var vData = new Vector<byte>(data.Slice(startIndex));
+                var r = Vector.Xor(vData, vKey);
+                r.CopyTo(data.Slice(startIndex));
+                startIndex += Vector<byte>.Count;
+            }
+
+            for (var i = startIndex; i < data.Length; i++)
+                data[i] = (byte)(data[i] ^ key);
+#else
+            NaiveXor(data, key);
+#endif
+        }
+
         public static string XOR(string text, string key)
         {
             var result = new StringBuilder();

GeometryDashAPI/GeometryDashAPI.csproj

@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFrameworks>netstandard2.1;netstandard2.0</TargetFrameworks>
+    <TargetFrameworks>netstandard2.1;netstandard2.0;net6.0</TargetFrameworks>
     <GeneratePackageOnBuild>true</GeneratePackageOnBuild>
     <Authors>Folleach</Authors>
     <NeutralLanguage>en</NeutralLanguage>