// 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 Internal.Microsoft.DotNet.PlatformAbstractions
{
    internal struct HashCodeCombiner
    {
        private long _combinedHash64;
 
        public int CombinedHash
        {
            [MethodImpl(MethodImplOptions.AggressiveInlining)]
            get { return _combinedHash64.GetHashCode(); }
        }
 
        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        private HashCodeCombiner(long seed)
        {
            _combinedHash64 = seed;
        }
 
        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        public void Add(int i)
        {
            _combinedHash64 = ((_combinedHash64 << 5) + _combinedHash64) ^ i;
        }
 
        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        public void Add(string s)
        {
            var hashCode = (s != null) ? s.GetHashCode() : 0;
            Add(hashCode);
        }
 
        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        public static HashCodeCombiner Start()
        {
            return new HashCodeCombiner(0x1505L);
        }
    }
}