CustomDebugInformationTableReader.cs

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using System.Reflection.Internal;
 
namespace System.Reflection.Metadata.Ecma335;
 
internal readonly struct CustomDebugInformationTableReader
{
    internal readonly int NumberOfRows;
 
    private readonly bool _isHasCustomDebugInformationRefSizeSmall;
 
    private readonly bool _isGuidHeapRefSizeSmall;
 
    private readonly bool _isBlobHeapRefSizeSmall;
 
    private readonly int _kindOffset;
 
    private readonly int _valueOffset;
 
    internal readonly int RowSize;
 
    internal readonly MemoryBlock Block;
 
    internal CustomDebugInformationTableReader(int numberOfRows, bool declaredSorted, int hasCustomDebugInformationRefSize, int guidHeapRefSize, int blobHeapRefSize, MemoryBlock containingBlock, int containingBlockOffset)
    {
        NumberOfRows = numberOfRows;
        _isHasCustomDebugInformationRefSizeSmall = hasCustomDebugInformationRefSize == 2;
        _isGuidHeapRefSizeSmall = guidHeapRefSize == 2;
        _isBlobHeapRefSizeSmall = blobHeapRefSize == 2;
        _kindOffset = hasCustomDebugInformationRefSize;
        _valueOffset = _kindOffset + guidHeapRefSize;
        RowSize = _valueOffset + blobHeapRefSize;
        Block = containingBlock.GetMemoryBlockAt(containingBlockOffset, RowSize * numberOfRows);
        if (numberOfRows > 0 && !declaredSorted)
        {
            Throw.TableNotSorted(TableIndex.CustomDebugInformation);
        }
    }
 
    internal EntityHandle GetParent(CustomDebugInformationHandle handle)
    {
        int offset = (handle.RowId - 1) * RowSize;
        return HasCustomDebugInformationTag.ConvertToHandle(Block.PeekTaggedReference(offset, _isHasCustomDebugInformationRefSizeSmall));
    }
 
    internal GuidHandle GetKind(CustomDebugInformationHandle handle)
    {
        int num = (handle.RowId - 1) * RowSize;
        return GuidHandle.FromIndex(Block.PeekHeapReference(num + _kindOffset, _isGuidHeapRefSizeSmall));
    }
 
    internal BlobHandle GetValue(CustomDebugInformationHandle handle)
    {
        int num = (handle.RowId - 1) * RowSize;
        return BlobHandle.FromOffset(Block.PeekHeapReference(num + _valueOffset, _isBlobHeapRefSizeSmall));
    }
 
    internal void GetRange(EntityHandle parentHandle, out int firstImplRowId, out int lastImplRowId)
    {
        Block.BinarySearchReferenceRange(NumberOfRows, RowSize, 0, HasCustomDebugInformationTag.ConvertToTag(parentHandle), _isHasCustomDebugInformationRefSizeSmall, out var startRowNumber, out var endRowNumber);
        if (startRowNumber == -1)
        {
            firstImplRowId = 1;
            lastImplRowId = 0;
        }
        else
        {
            firstImplRowId = startRowNumber + 1;
            lastImplRowId = endRowNumber + 1;
        }
    }
}