// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.

using System.Runtime.CompilerServices;

namespace System.Reflection.Metadata.Ecma335
{
    internal static class MemberRefParentTag
    {
        internal const int NumberOfBits = 3;
        internal const int LargeRowSize = 0x00000001 << (16 - NumberOfBits);
        internal const uint TypeDef = 0x00000000;
        internal const uint TypeRef = 0x00000001;
        internal const uint ModuleRef = 0x00000002;
        internal const uint MethodDef = 0x00000003;
        internal const uint TypeSpec = 0x00000004;
        internal const uint TagMask = 0x00000007;
        internal const TableMask TablesReferenced =
          TableMask.TypeDef
          | TableMask.TypeRef
          | TableMask.ModuleRef
          | TableMask.MethodDef
          | TableMask.TypeSpec;
        internal const ulong TagToTokenTypeByteVector =
            (ulong)TokenTypeIds.TypeDef >> 24
            | (ulong)TokenTypeIds.TypeRef >> 16
            | (ulong)TokenTypeIds.ModuleRef >> 8
            | (ulong)TokenTypeIds.MethodDef
            | (ulong)TokenTypeIds.TypeSpec << 8;

        [MethodImplAttribute(MethodImplOptions.AggressiveInlining)]
        internal static EntityHandle ConvertToHandle(uint memberRef)
        {
            uint tokenType = unchecked((uint)((TagToTokenTypeByteVector >> ((int)(memberRef & TagMask) << 3)) << TokenTypeIds.RowIdBitCount));
            uint rowId = (memberRef >> NumberOfBits);

            if (tokenType == 0 || (rowId & ~TokenTypeIds.RIDMask) != 0)
            {
                Throw.InvalidCodedIndex();
            }

            return new EntityHandle(tokenType | rowId);
        }
    }
}