using System;

using System.Collections.Generic;

using GeoAPI.Coordinates;

using NPack;

namespace SharpMap.Tests

{

public class EpsilonComparer : IComparer<Double>, IComparer<ICoordinate>

{

public static readonly Double DefaultEpsilon = 0.0005;

public static EpsilonComparer Default = new EpsilonComparer(DefaultEpsilon);

private readonly Double _epsilon;

private EpsilonComparer(Double epsilon)

{

_epsilon = epsilon;

}

public Int32 Compare(Double x, Double y)

{

Double difference = Math.Abs(x) - Math.Abs(y);

Int32 result = _epsilon.CompareTo(difference);

return result >= 0 ? 0 : x.CompareTo(y);

}

public Int32 Compare(ICoordinate x, ICoordinate y)

{

DoubleComponent[] xComponents = x.Components;

DoubleComponent[] yComponents = y.Components;

Int32 result = xComponents.Length.CompareTo(yComponents.Length);

if (result != 0)

{

return result;

}

for (Int32 i = 0; i < xComponents.Length; i++)

{

result = Compare((Double)xComponents[i], (Double)yComponents[i]);

if (result != 0)

{

return result;

}

}

return 0;

}

}

}