Fix IMC adding new variants.

Penumbra/Meta/Files/ImcFile.cs

@@ -70,6 +70,9 @@ public unsafe class ImcFile : MetaBaseFile
     public readonly int          NumParts;
     public          bool         ChangesSinceLoad = true;
 
+    public ReadOnlySpan< ImcEntry > Span
+        => new(( ImcEntry* )( Data + PreambleSize ), ( Length - PreambleSize ) / sizeof( ImcEntry ));
+
     private static int CountInternal( byte* data )
         => *( ushort* )data;
 
@@ -89,24 +92,15 @@ public unsafe class ImcFile : MetaBaseFile
 
     private static ImcEntry* VariantPtr( byte* data, int partIdx, int variantIdx )
     {
-        if( variantIdx == 0 )
-        {
-            return DefaultPartPtr( data, partIdx );
-        }
-
-        --variantIdx;
         var flag = 1 << partIdx;
-
+        if( ( PartMask( data ) & flag ) == 0 || variantIdx > CountInternal( data ) )
-        if( ( PartMask( data ) & flag ) == 0 || variantIdx >= CountInternal( data ) )
         {
             return null;
         }
 
         var numParts = BitOperations.PopCount( PartMask( data ) );
         var ptr      = ( ImcEntry* )( data + PreambleSize );
-        ptr += numParts;
+        ptr += variantIdx * numParts + partIdx;
-        ptr += variantIdx * numParts;
-        ptr += partIdx;
         return ptr;
     }
 
@@ -139,21 +133,22 @@ public unsafe class ImcFile : MetaBaseFile
             return true;
         }
 
+        var oldCount = Count;
+        *( ushort* )Data = ( ushort )numVariants;
         if( ActualLength > Length )
         {
-            PluginLog.Warning( "Adding too many variants to IMC, size exceeded." );
+            var newLength = ( ( ( ActualLength - 1 ) >> 7 ) + 1 ) << 7;
-            return false;
+            PluginLog.Verbose( "Resized IMC {Path} from {Length} to {NewLength}.", Path, Length, newLength );
+            ResizeResources( newLength );
         }
 
         var defaultPtr = ( ImcEntry* )( Data + PreambleSize );
-        var endPtr     = defaultPtr + ( numVariants + 1 ) * NumParts;
+        for( var i = oldCount + 1; i < numVariants + 1; ++i )
-        for( var ptr = defaultPtr + NumParts; ptr < endPtr; ptr += NumParts )
         {
-            Functions.MemCpyUnchecked( ptr, defaultPtr, NumParts * sizeof( ImcEntry ) );
+            Functions.MemCpyUnchecked( defaultPtr + i, defaultPtr, NumParts * sizeof( ImcEntry ) );
         }
 
-        PluginLog.Verbose( "Expanded imc from {Count} to {NewCount} variants.", Count, numVariants );
+        PluginLog.Verbose( "Expanded IMC {Path} from {Count} to {NewCount} variants.", Path, oldCount, numVariants );
-        *( ushort* )Data = ( ushort )numVariants;
         return true;
     }
 
@@ -240,7 +235,7 @@ public unsafe class ImcFile : MetaBaseFile
         }
 
         var requiredLength = ActualLength;
-        resource->SetData( (IntPtr) Data, Length );
+        resource->SetData( ( IntPtr )Data, Length );
         if( length >= requiredLength )
         {
             Functions.MemCpyUnchecked( ( void* )data, Data, requiredLength );

Penumbra/Meta/Files/MetaBaseFile.cs

@@ -1,5 +1,6 @@
 using System;
 using Dalamud.Memory;
+using Penumbra.GameData.Util;
 
 namespace Penumbra.Meta.Files;
 
@@ -44,6 +45,31 @@ public unsafe class MetaBaseFile : IDisposable
         Data   = null;
     }
 
+    // Resize memory while retaining data.
+    protected void ResizeResources( int newLength )
+    {
+        if( newLength == Length )
+        {
+            return;
+        }
+
+        var data = ( byte* )MemoryHelper.GameAllocateDefault( ( ulong )newLength );
+        if( newLength > Length )
+        {
+            Functions.MemCpyUnchecked( data, Data, Length );
+            Functions.MemSet( data + Length, 0, newLength - Length );
+        }
+        else
+        {
+            Functions.MemCpyUnchecked( data, Data, newLength );
+        }
+
+        ReleaseUnmanagedResources();
+        GC.AddMemoryPressure( newLength );
+        Data   = data;
+        Length = newLength;
+    }
+
     // Manually free memory. 
     public void Dispose()
     {

Penumbra/Meta/Manager/MetaManager.Imc.cs

@@ -20,7 +20,8 @@ public partial class MetaManager
         public readonly Dictionary< ImcManipulation, Mod.Mod > Manipulations = new();
 
         private readonly ModCollection                                     _collection;
-        private readonly ResourceLoader.ResourceLoadCustomizationDelegate? _previousDelegate;
+        private static   int                                               _imcManagerCount;
+        private static   ResourceLoader.ResourceLoadCustomizationDelegate? _previousDelegate;
 
 
         public MetaManagerImc( ModCollection collection )
@@ -97,18 +98,22 @@ public partial class MetaManager
 
             Files.Clear();
             Manipulations.Clear();
-            RestoreDelegate();
         }
 
         [Conditional( "USE_IMC" )]
-        private unsafe void SetupDelegate()
+        private static unsafe void SetupDelegate()
+        {
+            if( _imcManagerCount++ == 0 )
             {
                 Penumbra.ResourceLoader.ResourceLoadCustomization =  ImcLoadHandler;
                 Penumbra.ResourceLoader.ResourceLoaded            += ImcResourceHandler;
             }
+        }
 
         [Conditional( "USE_IMC" )]
-        private unsafe void RestoreDelegate()
+        private static unsafe void RestoreDelegate()
+        {
+            if( --_imcManagerCount == 0 )
             {
                 if( Penumbra.ResourceLoader.ResourceLoadCustomization == ImcLoadHandler )
                 {
@@ -117,6 +122,7 @@ public partial class MetaManager
 
                 Penumbra.ResourceLoader.ResourceLoaded -= ImcResourceHandler;
             }
+        }
 
         private FullPath CreateImcPath( Utf8GamePath path )
             => new($"|{_collection.Name}|{path}");