NestedClassTableReader.cs

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using System.Reflection.Internal;
 
namespace System.Reflection.Metadata.Ecma335;
 
internal readonly struct NestedClassTableReader
{
    internal readonly int NumberOfRows;
 
    private readonly bool _IsTypeDefTableRowRefSizeSmall;
 
    private readonly int _NestedClassOffset;
 
    private readonly int _EnclosingClassOffset;
 
    internal readonly int RowSize;
 
    internal readonly MemoryBlock Block;
 
    internal NestedClassTableReader(int numberOfRows, bool declaredSorted, int typeDefTableRowRefSize, MemoryBlock containingBlock, int containingBlockOffset)
    {
        NumberOfRows = numberOfRows;
        _IsTypeDefTableRowRefSizeSmall = typeDefTableRowRefSize == 2;
        _NestedClassOffset = 0;
        _EnclosingClassOffset = _NestedClassOffset + typeDefTableRowRefSize;
        RowSize = _EnclosingClassOffset + typeDefTableRowRefSize;
        Block = containingBlock.GetMemoryBlockAt(containingBlockOffset, RowSize * numberOfRows);
        if (!declaredSorted && !CheckSorted())
        {
            Throw.TableNotSorted(TableIndex.NestedClass);
        }
    }
 
    internal TypeDefinitionHandle GetNestedClass(int rowId)
    {
        int num = (rowId - 1) * RowSize;
        return TypeDefinitionHandle.FromRowId(Block.PeekReference(num + _NestedClassOffset, _IsTypeDefTableRowRefSizeSmall));
    }
 
    internal TypeDefinitionHandle GetEnclosingClass(int rowId)
    {
        int num = (rowId - 1) * RowSize;
        return TypeDefinitionHandle.FromRowId(Block.PeekReference(num + _EnclosingClassOffset, _IsTypeDefTableRowRefSizeSmall));
    }
 
    internal TypeDefinitionHandle FindEnclosingType(TypeDefinitionHandle nestedTypeDef)
    {
        int num = Block.BinarySearchReference(NumberOfRows, RowSize, _NestedClassOffset, (uint)nestedTypeDef.RowId, _IsTypeDefTableRowRefSizeSmall);
        if (num == -1)
        {
            return default(TypeDefinitionHandle);
        }
        return TypeDefinitionHandle.FromRowId(Block.PeekReference(num * RowSize + _EnclosingClassOffset, _IsTypeDefTableRowRefSizeSmall));
    }
 
    private bool CheckSorted()
    {
        return Block.IsOrderedByReferenceAscending(RowSize, _NestedClassOffset, _IsTypeDefTableRowRefSizeSmall);
    }
}