FieldTableReader.cs

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using System.Reflection.Internal;
 
namespace System.Reflection.Metadata.Ecma335;
 
internal readonly struct FieldTableReader
{
    internal readonly int NumberOfRows;
 
    private readonly bool _IsStringHeapRefSizeSmall;
 
    private readonly bool _IsBlobHeapRefSizeSmall;
 
    private readonly int _FlagsOffset;
 
    private readonly int _NameOffset;
 
    private readonly int _SignatureOffset;
 
    internal readonly int RowSize;
 
    internal readonly MemoryBlock Block;
 
    internal FieldTableReader(int numberOfRows, int stringHeapRefSize, int blobHeapRefSize, MemoryBlock containingBlock, int containingBlockOffset)
    {
        NumberOfRows = numberOfRows;
        _IsStringHeapRefSizeSmall = stringHeapRefSize == 2;
        _IsBlobHeapRefSizeSmall = blobHeapRefSize == 2;
        _FlagsOffset = 0;
        _NameOffset = _FlagsOffset + 2;
        _SignatureOffset = _NameOffset + stringHeapRefSize;
        RowSize = _SignatureOffset + blobHeapRefSize;
        Block = containingBlock.GetMemoryBlockAt(containingBlockOffset, RowSize * numberOfRows);
    }
 
    internal StringHandle GetName(FieldDefinitionHandle handle)
    {
        int num = (handle.RowId - 1) * RowSize;
        return StringHandle.FromOffset(Block.PeekHeapReference(num + _NameOffset, _IsStringHeapRefSizeSmall));
    }
 
    internal FieldAttributes GetFlags(FieldDefinitionHandle handle)
    {
        int num = (handle.RowId - 1) * RowSize;
        return (FieldAttributes)Block.PeekUInt16(num + _FlagsOffset);
    }
 
    internal BlobHandle GetSignature(FieldDefinitionHandle handle)
    {
        int num = (handle.RowId - 1) * RowSize;
        return BlobHandle.FromOffset(Block.PeekHeapReference(num + _SignatureOffset, _IsBlobHeapRefSizeSmall));
    }
}