Add bizhawk footer handler

Optimize some of the other handlers.

PKHeX.Core/Saves/SAV3GCMemoryCard.cs

@@ -1,4 +1,4 @@
-using System;
+using System;
 using System.Collections.Generic;
 using System.Text;
 using static System.Buffers.Binary.BinaryPrimitives;
@@ -242,7 +242,8 @@ public sealed class SAV3GCMemoryCard
 
             SaveGameCount = 0;
             var gameCode = EncodingType.GetString(Data, offset, 4);
-            var ver = SaveHandlerGCI.GetGameCode(gameCode);
+            var header = Data.AsSpan(0, 4);
+            var ver = SaveHandlerGCI.GetGameCode(header);
             if (ver == GameVersion.COLO)
             {
                 if (HasCOLO) // another entry already exists

PKHeX.Core/Saves/Util/Recognition/ISaveHandler.cs

@@ -1,4 +1,6 @@
-namespace PKHeX.Core;
+using System;
+
+namespace PKHeX.Core;
 #if !(EXCLUDE_EMULATOR_FORMATS && EXCLUDE_HACKS)
 /// <summary>
 /// Provides handling for recognizing atypical save file formats.
@@ -17,7 +19,7 @@ public interface ISaveHandler
     /// </summary>
     /// <param name="input">Combined data</param>
     /// <returns>Null if not a valid save file for this handler's format. Returns an object containing header, footer, and inner data references.</returns>
-    SaveHandlerSplitResult? TrySplit(byte[] input);
+    SaveHandlerSplitResult? TrySplit(ReadOnlySpan<byte> input);
 }
 #endif
 

PKHeX.Core/Saves/Util/Recognition/SaveHandlerARDS.cs

@@ -1,4 +1,4 @@
-using System;
+using System;
 
 namespace PKHeX.Core;
 
@@ -12,11 +12,11 @@ public sealed class SaveHandlerARDS : ISaveHandler
 
     public bool IsRecognized(int size) => size is ExpectedSize;
 
-    public SaveHandlerSplitResult TrySplit(byte[] input)
+    public SaveHandlerSplitResult TrySplit(ReadOnlySpan<byte> input)
     {
         // No authentication to see if it actually is a header; no size collisions expected.
-        var header = input.Slice(0, sizeHeader);
+        var header = input[..sizeHeader].ToArray();
-        input = input.SliceEnd(sizeHeader);
+        var data = input[sizeHeader..].ToArray();
-        return new SaveHandlerSplitResult(input, header, Array.Empty<byte>());
+        return new SaveHandlerSplitResult(data, header, Array.Empty<byte>());
     }
 }

PKHeX.Core/Saves/Util/Recognition/SaveHandlerBizHawk.cs

@@ -0,0 +1,35 @@
+using System;
+using static System.Buffers.Binary.BinaryPrimitives;
+
+namespace PKHeX.Core;
+
+/// <summary>
+/// Logic for recognizing .dsv save files from DeSmuME.
+/// </summary>
+public sealed class SaveHandlerBizHawk : ISaveHandler
+{
+    private const int sizeFooter = 0x16;
+
+    private static bool GetHasFooter(ReadOnlySpan<byte> input)
+    {
+        var start = input.Length - sizeFooter;
+        var footer = input[start..];
+        var _0x0b = ReadUInt16LittleEndian(footer[0x0B..]);
+        var _0x14 = ReadUInt16LittleEndian(footer[0x14..]);
+        return _0x0b == _0x14;
+    }
+
+    public bool IsRecognized(int size) => SaveUtil.IsSizeValidNoHandler(size - sizeFooter);
+
+    public SaveHandlerSplitResult? TrySplit(ReadOnlySpan<byte> input)
+    {
+        if (!GetHasFooter(input))
+            return null;
+
+        var realSize = input.Length - sizeFooter;
+        var footer = input[^realSize..].ToArray();
+        var data = input[..realSize].ToArray();
+
+        return new SaveHandlerSplitResult(data, Array.Empty<byte>(), footer);
+    }
+}

PKHeX.Core/Saves/Util/Recognition/SaveHandlerDeSmuME.cs

@@ -1,5 +1,4 @@
-using System;
+using System;
-using System.Text;
 
 namespace PKHeX.Core;
 
@@ -9,27 +8,34 @@ namespace PKHeX.Core;
 public sealed class SaveHandlerDeSmuME : ISaveHandler
 {
     private const int sizeFooter = 0x7A;
-    private const int ExpectedSize = SaveUtil.SIZE_G4RAW + sizeFooter;
+    private const int RealSize = SaveUtil.SIZE_G4RAW;
+    private const int ExpectedSize = RealSize + sizeFooter;
 
-    private static readonly byte[] FOOTER_DSV = Encoding.ASCII.GetBytes("|-DESMUME SAVE-|");
+    private const string SignatureDSV = "|-DESMUME SAVE-|";
 
-    private static bool GetHasFooterDSV(byte[] input)
+    private static bool GetHasFooter(ReadOnlySpan<byte> input)
     {
-        var signature = FOOTER_DSV;
+        var start = input.Length - SignatureDSV.Length;
-        var start = input.Length - signature.Length;
+        var footer = input[start..];
-        return input.AsSpan(start).SequenceEqual(signature);
+        for (int i = SignatureDSV.Length - 1; i >= 0; i--)
+        {
+            byte c = (byte)SignatureDSV[i];
+            if (footer[i] != c)
+                return false;
+        }
+        return true;
     }
 
     public bool IsRecognized(int size) => size is ExpectedSize;
 
-    public SaveHandlerSplitResult? TrySplit(byte[] input)
+    public SaveHandlerSplitResult? TrySplit(ReadOnlySpan<byte> input)
     {
-        if (!GetHasFooterDSV(input))
+        if (!GetHasFooter(input))
             return null;
 
-        var footer = input.SliceEnd(SaveUtil.SIZE_G4RAW);
+        var footer = input[^RealSize..].ToArray();
-        input = input.Slice(0, SaveUtil.SIZE_G4RAW);
+        var data = input[..RealSize].ToArray();
 
-        return new SaveHandlerSplitResult(input, Array.Empty<byte>(), footer);
+        return new SaveHandlerSplitResult(data, Array.Empty<byte>(), footer);
     }
 }

PKHeX.Core/Saves/Util/Recognition/SaveHandlerGCI.cs

@@ -1,7 +1,4 @@
-using System;
+using System;
-using System.Collections.Generic;
-using System.Linq;
-using System.Text;
 
 namespace PKHeX.Core;
 
@@ -19,11 +16,31 @@ public sealed class SaveHandlerGCI : ISaveHandler
     private static readonly string[] HEADER_XD    = { "GXXJ", "GXXE", "GXXP" }; // NTSC-J, NTSC-U, PAL
     private static readonly string[] HEADER_RSBOX = { "GPXJ", "GPXE", "GPXP" }; // NTSC-J, NTSC-U, PAL
 
-    private static bool IsGameMatchHeader(IEnumerable<string> headers, byte[] data) => headers.Contains(Encoding.ASCII.GetString(data, 0, 4));
+    private static bool IsGameMatchHeader(ReadOnlySpan<string> headers, ReadOnlySpan<byte> data)
+    {
+        foreach (var header in headers)
+        {
+            if (!IsGameMatchHeader(data, header.AsSpan()))
+                return false;
+        }
+        return true;
+    }
+
+    private static bool IsGameMatchHeader(ReadOnlySpan<byte> data, ReadOnlySpan<char> header)
+    {
+        for (int i = 0; i < header.Length; i++)
+        {
+            var c = (byte)header[i];
+            if (data[i] != c)
+                return false;
+        }
+
+        return true;
+    }
 
     public bool IsRecognized(int size) => size is SIZE_G3BOXGCI or SIZE_G3COLOGCI or SIZE_G3XDGCI;
 
-    public SaveHandlerSplitResult? TrySplit(byte[] input)
+    public SaveHandlerSplitResult? TrySplit(ReadOnlySpan<byte> input)
     {
         switch (input.Length)
         {
@@ -35,10 +52,10 @@ public sealed class SaveHandlerGCI : ISaveHandler
                 return null;
         }
 
-        byte[] header = input.Slice(0, headerSize);
+        var header = input[..headerSize].ToArray();
-        input = input.SliceEnd(headerSize);
+        var data = input[headerSize..].ToArray();
 
-        return new SaveHandlerSplitResult(input, header, Array.Empty<byte>());
+        return new SaveHandlerSplitResult(data, header, Array.Empty<byte>());
     }
 
     /// <summary>
@@ -46,13 +63,13 @@ public sealed class SaveHandlerGCI : ISaveHandler
     /// </summary>
     /// <param name="gameCode">4 character game code string</param>
     /// <returns>Magic version ID enumeration; <see cref="GameVersion.Unknown"/> if no match.</returns>
-    public static GameVersion GetGameCode(string gameCode)
+    public static GameVersion GetGameCode(ReadOnlySpan<byte> gameCode)
     {
-        if (HEADER_COLO.Contains(gameCode))
+        if (IsGameMatchHeader(HEADER_COLO, gameCode))
             return GameVersion.COLO;
-        if (HEADER_XD.Contains(gameCode))
+        if (IsGameMatchHeader(HEADER_XD, gameCode))
             return GameVersion.XD;
-        if (HEADER_RSBOX.Contains(gameCode))
+        if (IsGameMatchHeader(HEADER_RSBOX, gameCode))
             return GameVersion.RSBOX;
 
         return GameVersion.Unknown;

PKHeX.Core/Saves/Util/SaveUtil.cs

@@ -1,4 +1,4 @@
-using System;
+using System;
 using System.Collections.Generic;
 using System.IO;
 using System.Linq;
@@ -88,6 +88,7 @@ public static class SaveUtil
     {
         DolphinHandler,
         new SaveHandlerDeSmuME(),
+        new SaveHandlerBizHawk(),
         new SaveHandlerARDS(),
     };
 #endif
@@ -840,5 +841,17 @@ public static class SaveUtil
     /// </summary>
     /// <param name="size">Size in bytes of the save data</param>
     /// <returns>A boolean indicating whether or not the save data size is valid.</returns>
-    public static bool IsSizeValid(int size) => Sizes.Contains(size) || Handlers.Any(z => z.IsRecognized(size));
+    public static bool IsSizeValid(int size) => IsSizeValidNoHandler(size) || IsSizeValidHandler(size);
+
+    /// <summary>
+    /// Determines whether the save data size is valid for automatically detecting saves.
+    /// </summary>
+    /// <remarks>Only checks the <see cref="Handlers"/> list.</remarks>
+    public static bool IsSizeValidHandler(int size) => Handlers.Any(z => z.IsRecognized(size));
+
+    /// <summary>
+    /// Determines whether the save data size is valid for automatically detecting saves.
+    /// </summary>
+    /// <remarks>Does not check the <see cref="Handlers"/> list.</remarks>
+    public static bool IsSizeValidNoHandler(int size) => Sizes.Contains(size);
 }

PKHeX.WinForms/Util/WinFormsUtil.cs

@@ -246,7 +246,7 @@ public static class WinFormsUtil
         "gci", // Dolphin GameCubeImage
         "dsv", // DeSmuME
         "srm", // RetroArch save files
-        "fla", // flashcard
+        "fla", // flash
         "SaveRAM", // BizHawk
     };