Add Byte String stuff, remove Services, cleanup and refactor interop stuff, disable path resolver for the moment

Penumbra.GameData/ByteString/ByteStringFunctions.Case.cs

@@ -0,0 +1,94 @@
+using System.Linq;
+using System.Runtime.InteropServices;
+using Penumbra.GameData.Util;
+
+namespace Penumbra.GameData.ByteString;
+
+public static unsafe partial class ByteStringFunctions
+{
+    private static readonly byte[] AsciiLowerCaseBytes = Enumerable.Range( 0, 256 )
+       .Select( i => ( byte )char.ToLowerInvariant( ( char )i ) )
+       .ToArray();
+
+    // Convert a byte to its ASCII-lowercase version.
+    public static byte AsciiToLower( byte b )
+        => AsciiLowerCaseBytes[ b ];
+
+    // Check if a byte is ASCII-lowercase.
+    public static bool AsciiIsLower( byte b )
+        => AsciiToLower( b ) == b;
+
+    // Check if a byte array of given length is ASCII-lowercase.
+    public static bool IsAsciiLowerCase( byte* path, int length )
+    {
+        var end = path + length;
+        for( ; path < end; ++path )
+        {
+            if( *path != AsciiLowerCaseBytes[*path] )
+            {
+                return false;
+            }
+        }
+
+        return true;
+    }
+
+    // Compare two byte arrays of given lengths ASCII-case-insensitive.
+    public static int AsciiCaselessCompare( byte* lhs, int lhsLength, byte* rhs, int rhsLength )
+    {
+        if( lhsLength == rhsLength )
+        {
+            return lhs == rhs ? 0 : Functions.MemCmpCaseInsensitiveUnchecked( lhs, rhs, rhsLength );
+        }
+
+        if( lhsLength < rhsLength )
+        {
+            var cmp = Functions.MemCmpCaseInsensitiveUnchecked( lhs, rhs, lhsLength );
+            return cmp != 0 ? cmp : -1;
+        }
+
+        var cmp2 = Functions.MemCmpCaseInsensitiveUnchecked( lhs, rhs, rhsLength );
+        return cmp2 != 0 ? cmp2 : 1;
+    }
+
+    // Check two byte arrays of given lengths for ASCII-case-insensitive equality.
+    public static bool AsciiCaselessEquals( byte* lhs, int lhsLength, byte* rhs, int rhsLength )
+    {
+        if( lhsLength != rhsLength )
+        {
+            return false;
+        }
+
+        if( lhs == rhs || lhsLength == 0 )
+        {
+            return true;
+        }
+
+        return Functions.MemCmpCaseInsensitiveUnchecked( lhs, rhs, lhsLength ) == 0;
+    }
+
+    // Check if a byte array of given length consists purely of ASCII characters.
+    public static bool IsAscii( byte* path, int length )
+    {
+        var length8 = length / 8;
+        var end8    = ( ulong* )path + length8;
+        for( var ptr8 = ( ulong* )path; ptr8 < end8; ++ptr8 )
+        {
+            if( ( *ptr8 & 0x8080808080808080ul ) != 0 )
+            {
+                return false;
+            }
+        }
+
+        var end = path + length;
+        for( path += length8 * 8; path < end; ++path )
+        {
+            if( *path > 127 )
+            {
+                return false;
+            }
+        }
+
+        return true;
+    }
+}