﻿// ----------------------------------------------------------------------------------
// <copyright file="PrimitiveComparer.cs" company="NMemory Team">
//     Copyright (C) 2012-2014 NMemory Team
//
//     Permission is hereby granted, free of charge, to any person obtaining a copy
//     of this software and associated documentation files (the "Software"), to deal
//     in the Software without restriction, including without limitation the rights
//     to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
//     copies of the Software, and to permit persons to whom the Software is
//     furnished to do so, subject to the following conditions:
//
//     The above copyright notice and this permission notice shall be included in
//     all copies or substantial portions of the Software.
//
//     THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
//     IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
//     FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
//     AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
//     LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
//     OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
//     THE SOFTWARE.
// </copyright>
// ----------------------------------------------------------------------------------

namespace NMemory.Indexes
{
    using System.Collections.Generic;

    public static class PrimitiveKeyComparer
    {
        public static int Compare<T>(T x, T y, SortOrder sortOder)
        {
            // Examination of null might not need
            if (x == null && y != null)
            {
                return EvaluateResult(-1, sortOder);
            }

            if (x != null && y == null)
            {
                return EvaluateResult(1, sortOder);
            }

            if (x == null && y == null)
            {
                return 0;
            }

            int result = Comparer<T>.Default.Compare(x, y);

            return EvaluateResult(result, sortOder);
        }

        private static int EvaluateResult(int result, SortOrder sortOrder)
        {
            if (sortOrder == SortOrder.Ascending)
            {
                return result;
            }
            else
            {
                return -result;
            }
        }
    }
}
