Add PBD Post-Processor that appends EPBD data if the loaded PBD does not contain it.

Penumbra/Interop/Hooks/PostProcessing/PreBoneDeformerReplacer.cs

@@ -63,7 +63,7 @@ public sealed unsafe class PreBoneDeformerReplacer : IDisposable, IRequiredServi
         if (!_framework.IsInFrameworkUpdateThread)
             Penumbra.Log.Warning(
                 $"{nameof(PreBoneDeformerReplacer)}.{nameof(SetupHssReplacements)}(0x{(nint)drawObject:X}, {slotIndex}) called out of framework thread");
-
+        
         var preBoneDeformer = GetPreBoneDeformerForCharacter(drawObject);
         try
         {

Penumbra/Interop/Processing/PbdFilePostProcessor.cs

@@ -0,0 +1,119 @@
+using Dalamud.Game;
+using Dalamud.Plugin.Services;
+using Penumbra.Api.Enums;
+using Penumbra.GameData;
+using Penumbra.GameData.Data;
+using Penumbra.Interop.Structs;
+using Penumbra.Meta.Files;
+using Penumbra.String;
+
+namespace Penumbra.Interop.Processing;
+
+public sealed class PbdFilePostProcessor : IFilePostProcessor
+{
+    private readonly IFileAllocator                             _allocator;
+    private          byte[]                                     _epbdData;
+    private unsafe   delegate* unmanaged<ResourceHandle*, void> _loadEpbdData;
+
+    public ResourceType Type
+        => ResourceType.Pbd;
+
+    public unsafe PbdFilePostProcessor(IDataManager dataManager, XivFileAllocator allocator, ISigScanner scanner)
+    {
+        _allocator    = allocator;
+        _epbdData     = SetEpbdData(dataManager);
+        _loadEpbdData = (delegate* unmanaged<ResourceHandle*, void>)scanner.ScanText(Sigs.LoadEpbdData);
+    }
+
+    public unsafe void PostProcess(ResourceHandle* resource, CiByteString originalGamePath, ReadOnlySpan<byte> additionalData)
+    {
+        if (_epbdData.Length is 0)
+            return;
+
+        if (resource->LoadState is not LoadState.Success)
+        {
+            Penumbra.Log.Warning($"[ResourceLoader] Requested PBD at {originalGamePath} failed load ({resource->LoadState}).");
+            return;
+        }
+
+        var (data, length) = resource->GetData();
+        if (length is 0 || data == nint.Zero)
+        {
+            Penumbra.Log.Warning($"[ResourceLoader] Requested PBD at {originalGamePath} succeeded load but has no data.");
+            return;
+        }
+
+        var span   = new ReadOnlySpan<byte>((void*)data, (int)resource->FileSize);
+        var reader = new PackReader(span);
+        if (reader.HasData)
+        {
+            Penumbra.Log.Excessive($"[ResourceLoader] Successfully loaded PBD at {originalGamePath} with EPBD data.");
+            return;
+        }
+
+        var newData = AppendData(span);
+        fixed (byte* ptr = newData)
+        {
+            // Set the appended data and the actual file size, then re-load the EPBD data via game function call.
+            if (resource->SetData((nint)ptr, newData.Length))
+            {
+                resource->FileSize           = (uint)newData.Length;
+                resource->CsHandle.FileSize2 = (uint)newData.Length;
+                resource->CsHandle.FileSize3 = (uint)newData.Length;
+                _loadEpbdData(resource);
+                // Free original data.
+                _allocator.Release((void*)data, length);
+                Penumbra.Log.Verbose($"[ResourceLoader] Loaded {originalGamePath} from file and appended default EPBD data.");
+            }
+            else
+            {
+                Penumbra.Log.Warning(
+                    $"[ResourceLoader] Failed to append EPBD data to custom PBD at {originalGamePath}.");
+            }
+        }
+    }
+
+    /// <summary> Combine the given data with the default PBD data using the game's file allocator. </summary>
+    private unsafe ReadOnlySpan<byte> AppendData(ReadOnlySpan<byte> data)
+    {
+        // offset has to be set, otherwise not called.
+        var newLength = data.Length + _epbdData.Length;
+        var memory    = _allocator.Allocate(newLength);
+        var span      = new Span<byte>(memory, newLength);
+        data.CopyTo(span);
+        _epbdData.CopyTo(span[data.Length..]);
+        return span;
+    }
+
+    /// <summary> Fetch the default EPBD data from the .pbd file of the game's installation. </summary>
+    private static byte[] SetEpbdData(IDataManager dataManager)
+    {
+        try
+        {
+            var file = dataManager.GetFile(GamePaths.Pbd.Path);
+            if (file is null || file.Data.Length is 0)
+            {
+                Penumbra.Log.Warning("Default PBD file has no data.");
+                return [];
+            }
+
+            ReadOnlySpan<byte> span   = file.Data;
+            var                reader = new PackReader(span);
+            if (!reader.HasData)
+            {
+                Penumbra.Log.Warning("Default PBD file has no EPBD section.");
+                return [];
+            }
+
+            var offset = span.Length - (int)reader.PackLength;
+            var ret    = span[offset..];
+            Penumbra.Log.Verbose($"Default PBD file has EPBD section of length {ret.Length} at offset {offset}.");
+            return ret.ToArray();
+        }
+        catch (Exception ex)
+        {
+            Penumbra.Log.Error($"Unknown error getting default EPBD data:\n{ex}");
+            return [];
+        }
+    }
+}