// Copyright (c) 2010-2013 AlphaSierraPapa for the SharpDevelop 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.

using System;

using System.Collections.Generic;

namespace ICSharpCode.NRefactory.Utils

{

public static class KeyComparer

{

public static KeyComparer<TElement, TKey> Create<TElement, TKey>(Func<TElement, TKey> keySelector)

{

return new KeyComparer<TElement, TKey>(keySelector, Comparer<TKey>.Default, EqualityComparer<TKey>.Default);

}

public static KeyComparer<TElement, TKey> Create<TElement, TKey>(Func<TElement, TKey> keySelector, IComparer<TKey> comparer, IEqualityComparer<TKey> equalityComparer)

{

return new KeyComparer<TElement, TKey>(keySelector, comparer, equalityComparer);

}

public static IComparer<TElement> Create<TElement, TKey>(Func<TElement, TKey> keySelector, IComparer<TKey> comparer)

{

return new KeyComparer<TElement, TKey>(keySelector, comparer, EqualityComparer<TKey>.Default);

}

public static IEqualityComparer<TElement> Create<TElement, TKey>(Func<TElement, TKey> keySelector, IEqualityComparer<TKey> equalityComparer)

{

return new KeyComparer<TElement, TKey>(keySelector, Comparer<TKey>.Default, equalityComparer);

}

}

public class KeyComparer<TElement, TKey> : IComparer<TElement>, IEqualityComparer<TElement>

{

readonly Func<TElement, TKey> keySelector;

readonly IComparer<TKey> keyComparer;

readonly IEqualityComparer<TKey> keyEqualityComparer;

public KeyComparer(Func<TElement, TKey> keySelector, IComparer<TKey> keyComparer, IEqualityComparer<TKey> keyEqualityComparer)

{

if (keySelector == null)

throw new ArgumentNullException("keySelector");

if (keyComparer == null)

throw new ArgumentNullException("keyComparer");

if (keyEqualityComparer == null)

throw new ArgumentNullException("keyEqualityComparer");

this.keySelector = keySelector;

this.keyComparer = keyComparer;

this.keyEqualityComparer = keyEqualityComparer;

}

public int Compare(TElement x, TElement y)

{

return keyComparer.Compare(keySelector(x), keySelector(y));

}

public bool Equals(TElement x, TElement y)

{

return keyEqualityComparer.Equals(keySelector(x), keySelector(y));

}

public int GetHashCode(TElement obj)

{

return keyEqualityComparer.GetHashCode(keySelector(obj));

}

}

}