FieldLayoutTableReader.cs

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using System.Reflection.Internal;
 
namespace System.Reflection.Metadata.Ecma335;
 
internal readonly struct FieldLayoutTableReader
{
    internal readonly int NumberOfRows;
 
    private readonly bool _IsFieldTableRowRefSizeSmall;
 
    private readonly int _OffsetOffset;
 
    private readonly int _FieldOffset;
 
    internal readonly int RowSize;
 
    internal readonly MemoryBlock Block;
 
    internal FieldLayoutTableReader(int numberOfRows, bool declaredSorted, int fieldTableRowRefSize, MemoryBlock containingBlock, int containingBlockOffset)
    {
        NumberOfRows = numberOfRows;
        _IsFieldTableRowRefSizeSmall = fieldTableRowRefSize == 2;
        _OffsetOffset = 0;
        _FieldOffset = _OffsetOffset + 4;
        RowSize = _FieldOffset + fieldTableRowRefSize;
        Block = containingBlock.GetMemoryBlockAt(containingBlockOffset, RowSize * numberOfRows);
        if (!declaredSorted && !CheckSorted())
        {
            Throw.TableNotSorted(TableIndex.FieldLayout);
        }
    }
 
    internal int FindFieldLayoutRowId(FieldDefinitionHandle handle)
    {
        int num = Block.BinarySearchReference(NumberOfRows, RowSize, _FieldOffset, (uint)handle.RowId, _IsFieldTableRowRefSizeSmall);
        return num + 1;
    }
 
    internal uint GetOffset(int rowId)
    {
        int num = (rowId - 1) * RowSize;
        return Block.PeekUInt32(num + _OffsetOffset);
    }
 
    internal FieldDefinitionHandle GetField(int rowId)
    {
        int num = (rowId - 1) * RowSize;
        return FieldDefinitionHandle.FromRowId(Block.PeekReference(num + _FieldOffset, _IsFieldTableRowRefSizeSmall));
    }
 
    private bool CheckSorted()
    {
        return Block.IsOrderedByReferenceAscending(RowSize, _FieldOffset, _IsFieldTableRowRefSizeSmall);
    }
}