using System.Collections.Generic;
using System.Runtime.CompilerServices;

namespace StardewModdingAPI.Framework.StateTracking.Comparers
{
    /// <summary>A comparer which considers two references equal if they point to the same instance.</summary>
    /// <typeparam name="T">The value type.</typeparam>
    internal class ObjectReferenceComparer<T> : IEqualityComparer<T>
    {
        /*********
        ** Public methods
        *********/
        /// <summary>Determines whether the specified objects are equal.</summary>
        /// <returns>true if the specified objects are equal; otherwise, false.</returns>
        /// <param name="x">The first object to compare.</param>
        /// <param name="y">The second object to compare.</param>
        public bool Equals(T x, T y)
        {
            return object.ReferenceEquals(x, y);
        }

        /// <summary>Get a hash code for the specified object.</summary>
        /// <param name="obj">The value.</param>
        public int GetHashCode(T obj)
        {
            return RuntimeHelpers.GetHashCode(obj);
        }
    }
}