GenericParamConstraintTableReader.cs

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using System.Reflection.Internal;
 
namespace System.Reflection.Metadata.Ecma335;
 
internal readonly struct GenericParamConstraintTableReader
{
    internal readonly int NumberOfRows;
 
    private readonly bool _IsGenericParamTableRowRefSizeSmall;
 
    private readonly bool _IsTypeDefOrRefRefSizeSmall;
 
    private readonly int _OwnerOffset;
 
    private readonly int _ConstraintOffset;
 
    internal readonly int RowSize;
 
    internal readonly MemoryBlock Block;
 
    internal GenericParamConstraintTableReader(int numberOfRows, bool declaredSorted, int genericParamTableRowRefSize, int typeDefOrRefRefSize, MemoryBlock containingBlock, int containingBlockOffset)
    {
        NumberOfRows = numberOfRows;
        _IsGenericParamTableRowRefSizeSmall = genericParamTableRowRefSize == 2;
        _IsTypeDefOrRefRefSizeSmall = typeDefOrRefRefSize == 2;
        _OwnerOffset = 0;
        _ConstraintOffset = _OwnerOffset + genericParamTableRowRefSize;
        RowSize = _ConstraintOffset + typeDefOrRefRefSize;
        Block = containingBlock.GetMemoryBlockAt(containingBlockOffset, RowSize * numberOfRows);
        if (!declaredSorted && !CheckSorted())
        {
            Throw.TableNotSorted(TableIndex.GenericParamConstraint);
        }
    }
 
    internal GenericParameterConstraintHandleCollection FindConstraintsForGenericParam(GenericParameterHandle genericParameter)
    {
        Block.BinarySearchReferenceRange(NumberOfRows, RowSize, _OwnerOffset, (uint)genericParameter.RowId, _IsGenericParamTableRowRefSizeSmall, out var startRowNumber, out var endRowNumber);
        if (startRowNumber == -1)
        {
            return default(GenericParameterConstraintHandleCollection);
        }
        return new GenericParameterConstraintHandleCollection(startRowNumber + 1, (ushort)(endRowNumber - startRowNumber + 1));
    }
 
    private bool CheckSorted()
    {
        return Block.IsOrderedByReferenceAscending(RowSize, _OwnerOffset, _IsGenericParamTableRowRefSizeSmall);
    }
 
    internal EntityHandle GetConstraint(GenericParameterConstraintHandle handle)
    {
        int num = (handle.RowId - 1) * RowSize;
        return TypeDefOrRefTag.ConvertToHandle(Block.PeekTaggedReference(num + _ConstraintOffset, _IsTypeDefOrRefRefSizeSmall));
    }
 
    internal GenericParameterHandle GetOwner(GenericParameterConstraintHandle handle)
    {
        int num = (handle.RowId - 1) * RowSize;
        return GenericParameterHandle.FromRowId(Block.PeekReference(num + _OwnerOffset, _IsGenericParamTableRowRefSizeSmall));
    }
}