ClassLayoutTableReader.cs

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using System.Reflection.Internal;
 
namespace System.Reflection.Metadata.Ecma335;
 
internal struct ClassLayoutTableReader
{
    internal int NumberOfRows;
 
    private readonly bool _IsTypeDefTableRowRefSizeSmall;
 
    private readonly int _PackagingSizeOffset;
 
    private readonly int _ClassSizeOffset;
 
    private readonly int _ParentOffset;
 
    internal readonly int RowSize;
 
    internal MemoryBlock Block;
 
    internal ClassLayoutTableReader(int numberOfRows, bool declaredSorted, int typeDefTableRowRefSize, MemoryBlock containingBlock, int containingBlockOffset)
    {
        NumberOfRows = numberOfRows;
        _IsTypeDefTableRowRefSizeSmall = typeDefTableRowRefSize == 2;
        _PackagingSizeOffset = 0;
        _ClassSizeOffset = _PackagingSizeOffset + 2;
        _ParentOffset = _ClassSizeOffset + 4;
        RowSize = _ParentOffset + typeDefTableRowRefSize;
        Block = containingBlock.GetMemoryBlockAt(containingBlockOffset, RowSize * numberOfRows);
        if (!declaredSorted && !CheckSorted())
        {
            Throw.TableNotSorted(TableIndex.ClassLayout);
        }
    }
 
    internal TypeDefinitionHandle GetParent(int rowId)
    {
        int num = (rowId - 1) * RowSize;
        return TypeDefinitionHandle.FromRowId(Block.PeekReference(num + _ParentOffset, _IsTypeDefTableRowRefSizeSmall));
    }
 
    internal ushort GetPackingSize(int rowId)
    {
        int num = (rowId - 1) * RowSize;
        return Block.PeekUInt16(num + _PackagingSizeOffset);
    }
 
    internal uint GetClassSize(int rowId)
    {
        int num = (rowId - 1) * RowSize;
        return Block.PeekUInt32(num + _ClassSizeOffset);
    }
 
    internal int FindRow(TypeDefinitionHandle typeDef)
    {
        return 1 + Block.BinarySearchReference(NumberOfRows, RowSize, _ParentOffset, (uint)typeDef.RowId, _IsTypeDefTableRowRefSizeSmall);
    }
 
    private bool CheckSorted()
    {
        return Block.IsOrderedByReferenceAscending(RowSize, _ParentOffset, _IsTypeDefTableRowRefSizeSmall);
    }
}