From dea5949035b4d093be262701a3720cb537223b69 Mon Sep 17 00:00:00 2001
From: Natalia Portillo <claunia@claunia.com>
Date: Fri, 8 Aug 2025 21:05:08 +0100
Subject: [PATCH] Add benchmark for BAT swapping.

---
 AaruBenchmark/Algorithms/BatSwapping.cs | 99 +++++++++++++++++++++++++
 AaruBenchmark/Program.cs                | 15 +++-
 2 files changed, 110 insertions(+), 4 deletions(-)
 create mode 100644 AaruBenchmark/Algorithms/BatSwapping.cs

diff --git a/AaruBenchmark/Algorithms/BatSwapping.cs b/AaruBenchmark/Algorithms/BatSwapping.cs
new file mode 100644
index 0000000..2e358b5
--- /dev/null
+++ b/AaruBenchmark/Algorithms/BatSwapping.cs
@@ -0,0 +1,99 @@
+#if NET10_0_OR_GREATER
+using System;
+using System.Linq;
+using System.Runtime.CompilerServices;
+using System.Runtime.InteropServices;
+using System.Threading.Tasks;
+using BenchmarkDotNet.Attributes;
+using BenchmarkDotNet.Jobs;
+
+namespace AaruBenchmark.Algorithms;
+
+[SimpleJob(RuntimeMoniker.Net10_0)]
+[SimpleJob(RuntimeMoniker.NativeAot10_0)]
+[MemoryDiagnoser(false)]
+[HideColumns("Job", "Error", "StdDev", "Median", "RatioSD", "Alloc Ratio")]
+public class BatSwapping
+{
+    byte[] _batData;
+
+    [GlobalSetup]
+    public void Setup()
+    {
+        _batData = new byte[1024 * 1024];   // 1 MB
+        new Random(42).NextBytes(_batData); // Fill with deterministic random bytes
+    }
+
+    [Benchmark(Baseline = true)]
+    public void Loop()
+    {
+        ReadOnlySpan<byte> span = _batData;
+
+        uint[] blockAllocationTable =
+            MemoryMarshal.Cast<byte, uint>(span)[..(_batData.Length / sizeof(uint))].ToArray();
+
+        uint test = Swap(blockAllocationTable[1024]);
+
+        // Swap all uint endianness
+        for(int i = 0; i < blockAllocationTable.Length; i++) blockAllocationTable[i] = Swap(blockAllocationTable[i]);
+
+        if(test != blockAllocationTable[1024]) throw new Exception("Swapping failed");
+    }
+
+    [Benchmark]
+    public void ParallelLoop()
+    {
+        ReadOnlySpan<byte> span = _batData;
+
+        uint[] blockAllocationTable =
+            MemoryMarshal.Cast<byte, uint>(span)[..(_batData.Length / sizeof(uint))].ToArray();
+
+        uint test = Swap(blockAllocationTable[1024]);
+
+        // Swap all uint endianness
+        Parallel.For(0, blockAllocationTable.Length, i => { blockAllocationTable[i] = Swap(blockAllocationTable[i]); });
+
+        if(test != blockAllocationTable[1024]) throw new Exception("Swapping failed");
+    }
+
+    [Benchmark]
+    public void Linq()
+    {
+        ReadOnlySpan<byte> span = _batData;
+
+        uint[] blockAllocationTable =
+            MemoryMarshal.Cast<byte, uint>(span)[..(_batData.Length / sizeof(uint))].ToArray();
+
+        uint test = Swap(blockAllocationTable[1024]);
+
+        // Swap all uint endianness
+        blockAllocationTable = blockAllocationTable.Select(Swap).ToArray();
+
+        if(test != blockAllocationTable[1024]) throw new Exception("Swapping failed");
+    }
+
+    [Benchmark]
+    public void ParallelLinq()
+    {
+        ReadOnlySpan<byte> span = _batData;
+
+        uint[] blockAllocationTable =
+            MemoryMarshal.Cast<byte, uint>(span)[..(_batData.Length / sizeof(uint))].ToArray();
+
+        uint test = Swap(blockAllocationTable[1024]);
+
+        // Swap all uint endianness
+        blockAllocationTable = blockAllocationTable.AsParallel().AsOrdered().Select(Swap).ToArray();
+
+        if(test != blockAllocationTable[1024]) throw new Exception("Swapping failed");
+    }
+
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    public static uint Swap(uint x)
+    {
+        x = x << 8 & 0xFF00FF00 | x >> 8 & 0xFF00FF;
+
+        return x << 16 | x >> 16;
+    }
+}
+#endif
\ No newline at end of file
diff --git a/AaruBenchmark/Program.cs b/AaruBenchmark/Program.cs
index 40ce8c9..d147cc1 100644
--- a/AaruBenchmark/Program.cs
+++ b/AaruBenchmark/Program.cs
@@ -3,6 +3,9 @@ using System.Globalization;
 using System.IO;
 using BenchmarkDotNet.Configs;
 using BenchmarkDotNet.Running;
+#if NET10_0_OR_GREATER
+using AaruBenchmark.Algorithms;
+#endif
 
 // ReSharper disable ArrangeNamespaceBody
 
@@ -17,14 +20,14 @@ namespace AaruBenchmark
             var config = ManualConfig.Create(DefaultConfig.Instance);
             config.CultureInfo = CultureInfo.InvariantCulture;
 
-       /*     BenchmarkRunner.Run<ADCBenchs>(config);
+            BenchmarkRunner.Run<ADCBenchs>(config);
             BenchmarkRunner.Run<AppleRleBenchs>(config);
             BenchmarkRunner.Run<TeleDiskLzhBenchs>(config);
             BenchmarkRunner.Run<GzipBenchs>(config);
             BenchmarkRunner.Run<Bzip2Benchs>(config);
-            BenchmarkRunner.Run<LzipBenchs>(config);*/
+            BenchmarkRunner.Run<LzipBenchs>(config);
             BenchmarkRunner.Run<LzmaBenchs>(config);
-            /*BenchmarkRunner.Run<FlacBenchs>(config);
+            BenchmarkRunner.Run<FlacBenchs>(config);
             BenchmarkRunner.Run<CompressGzipBenchs>(config);
             BenchmarkRunner.Run<CompressBzip2Benchs>(config);
             BenchmarkRunner.Run<CompressLzipBenchs>(config);
@@ -43,7 +46,11 @@ namespace AaruBenchmark
             BenchmarkRunner.Run<Sha384Benchs>(config);
             BenchmarkRunner.Run<Sha512Benchs>(config);
             BenchmarkRunner.Run<SpamSumBenchs>(config);
-            BenchmarkRunner.Run<LambdaBenchs>(config);*/
+            BenchmarkRunner.Run<LambdaBenchs>(config);
+
+#if NET10_0_OR_GREATER
+            BenchmarkRunner.Run<BatSwapping>(config);
+#endif
         }
     }
 }
\ No newline at end of file