/source/library/Interlace/Utilities/Pair.cs

#region Using Directives and Copyright Notice



// Copyright (c) 2007-2010, Computer Consultancy Pty Ltd

// All rights reserved.

// 

// Redistribution and use in source and binary forms, with or without

// modification, are permitted provided that the following conditions are met:

//     * Redistributions of source code must retain the above copyright

//       notice, this list of conditions and the following disclaimer.

//     * Redistributions in binary form must reproduce the above copyright

//       notice, this list of conditions and the following disclaimer in the

//       documentation and/or other materials provided with the distribution.

//     * Neither the name of the Computer Consultancy Pty Ltd nor the

//       names of its contributors may be used to endorse or promote products

//       derived from this software without specific prior written permission.

// 

// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" 

// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 

// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 

// ARE DISCLAIMED. IN NO EVENT SHALL COMPUTER CONSULTANCY PTY LTD BE LIABLE 

// FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 

// DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR 

// SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER 

// CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 

// LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 

// OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH

// DAMAGE.



using System;

using System.Collections.Generic;

using System.Text;



#endregion



namespace Interlace.Utilities

{

    [Serializable]

    public class Pair<F, S> : IComparable

    {

        readonly F _first;

        readonly S _second;



        public Pair(F first, S second)

        {

            _first = first;

            _second = second;

        }



        public F First

        {

            get { return _first; }

        }



        public S Second

        {

            get { return _second; }

        }



        public override bool Equals(object obj)

        {

            Pair<F, S> rhs = obj as Pair<F, S>;



            if (rhs == null) return false;



            return Object.Equals(_first, rhs._first) && Object.Equals(_second, rhs._second);

        }



        public override int GetHashCode()

        {

            int hash = 0;



            if (_first != null) hash ^= _first.GetHashCode();

            if (_second != null) hash ^= ~_second.GetHashCode();



            return hash;

        }



        public override string ToString()

        {

            return string.Format("({0}, {1})", _first.ToString(), _second.ToString());

        }



        public int CompareTo(object obj)

        {

            if (!(obj is Pair<F, S>)) throw new InvalidOperationException(

                "A Pair instance can only be compared to another Pair instant with " +

                "exactly the same generic type arguments.");



            Pair<F, S> rhs = obj as Pair<F, S>;



            if (rhs == null) return 1;



            IComparable firstComparable = _first as IComparable;

            IComparable secondComparable = _second as IComparable;



            if (firstComparable != null)

            {

                int comparison = firstComparable.CompareTo(rhs.First);



                if (comparison != 0) return comparison;

            }



            if (secondComparable != null)

            {

                return secondComparable.CompareTo(rhs.Second);

            }



            // If neither are comparable, consider the objects identical:

            return 0;

        }

    }

}