From 23e1447ab63ca8ccfb8fbc867e086f369bf1d0a1 Mon Sep 17 00:00:00 2001
From: majorro <majorrowk@gmail.com>
Date: Mon, 13 Jan 2025 23:31:33 +0300
Subject: [PATCH] stackalloc addvmcode

---
 src/SharpCompress/Compressors/Rar/RarCRC.cs          | 2 +-
 src/SharpCompress/Compressors/Rar/UnpackV1/Unpack.cs | 2 +-
 src/SharpCompress/Compressors/Rar/VM/RarVM.cs        | 6 +++---
 3 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/src/SharpCompress/Compressors/Rar/RarCRC.cs b/src/SharpCompress/Compressors/Rar/RarCRC.cs
index 8f4fb47e..7e6fc6cc 100644
--- a/src/SharpCompress/Compressors/Rar/RarCRC.cs
+++ b/src/SharpCompress/Compressors/Rar/RarCRC.cs
@@ -9,7 +9,7 @@ internal static class RarCRC
     public static uint CheckCrc(uint startCrc, byte b) =>
         (crcTab[((int)startCrc ^ b) & 0xff] ^ (startCrc >> 8));
 
-    public static uint CheckCrc(uint startCrc, byte[] data, int offset, int count)
+    public static uint CheckCrc(uint startCrc, ReadOnlySpan<byte> data, int offset, int count)
     {
         var size = Math.Min(data.Length - offset, count);
 
diff --git a/src/SharpCompress/Compressors/Rar/UnpackV1/Unpack.cs b/src/SharpCompress/Compressors/Rar/UnpackV1/Unpack.cs
index 1af0965c..eb2ddea6 100644
--- a/src/SharpCompress/Compressors/Rar/UnpackV1/Unpack.cs
+++ b/src/SharpCompress/Compressors/Rar/UnpackV1/Unpack.cs
@@ -1197,7 +1197,7 @@ internal sealed partial class Unpack : BitInput, IRarUnpack, IDisposable
             {
                 return (false);
             }
-            var VMCode = new byte[VMCodeSize];
+            Span<byte> VMCode = stackalloc byte[VMCodeSize];
             for (var I = 0; I < VMCodeSize; I++)
             {
                 if (Inp.Overflow(3))
diff --git a/src/SharpCompress/Compressors/Rar/VM/RarVM.cs b/src/SharpCompress/Compressors/Rar/VM/RarVM.cs
index f758b8a4..0dd3e326 100644
--- a/src/SharpCompress/Compressors/Rar/VM/RarVM.cs
+++ b/src/SharpCompress/Compressors/Rar/VM/RarVM.cs
@@ -776,14 +776,14 @@ internal sealed class RarVM : BitInput
         }
     }
 
-    public void prepare(byte[] code, int codeSize, VMPreparedProgram prg)
+    public void prepare(ReadOnlySpan<byte> code, int codeSize, VMPreparedProgram prg)
     {
         InitBitInput();
         var cpLength = Math.Min(MAX_SIZE, codeSize);
 
         // memcpy(inBuf,Code,Min(CodeSize,BitInput::MAX_SIZE));
 
-        Buffer.BlockCopy(code, 0, InBuf, 0, cpLength);
+        code.Slice(0, cpLength).CopyTo(InBuf);
         byte xorSum = 0;
         for (var i = 1; i < codeSize; i++)
         {
@@ -1105,7 +1105,7 @@ internal sealed class RarVM : BitInput
         }
     }
 
-    private VMStandardFilters IsStandardFilter(byte[] code, int codeSize)
+    private VMStandardFilters IsStandardFilter(ReadOnlySpan<byte> code, int codeSize)
     {
         VMStandardFilterSignature[] stdList =
         {