/// <summary>
/// Tests an interval to see if it wholly contains another interval.
/// </summary>
/// <typeparam name="T">The type of values included in the intervals.</typeparam>
/// <param name="interval">The interval to test.</param>
/// <param name="other">The other interval.</param>
/// <returns>true, if <paramref name="interval"/> contains <paramref name="other"/>; false, otherwise.</returns>
/// <remarks>
/// All intervals (including empty ones) contain every other empty interval. So, if <paramref name="other"/> is empty, this method always returns true.
/// Otherwise, this method only returns true if the start and end values of <paramref name="interval"/> surround the values of <paramref name="other"/>.
/// </remarks>
public static bool Contains <T>(this IInterval <T> interval, IInterval <T> other) where T : IComparable <T>
{
if (other.IsEmpty())
{
return(true);
}
var intersection = other.IntersectWith(interval);
return(!intersection.IsEmpty() &&
intersection == other);
}
/// <summary>
/// Returns the difference of one interval to another.
/// </summary>
/// <typeparam name="T">The type of values included in the intervals.</typeparam>
/// <param name="interval">The source interval.</param>
/// <param name="other">The interval to exclude.</param>
/// <returns>A set that contains every part of <paramref name="interval"/> that is not also contained by <paramref name="other"/>.</returns>
public static IList <IInterval <T> > DifferenceWith <T>(this IInterval <T> interval, IInterval <T> other) where T : IComparable <T>
{
if (interval.IsEmpty())
{
return(null);
}
var intersection = interval.IntersectWith(other);
if (intersection.IsEmpty())
{
return(new[] { interval });
}
else if (intersection == interval)
{
return(null);
}
var intervals = new List <IInterval <T> >();
var startToStart = interval.Start.CompareTo(intersection.Start);
if (startToStart != 0 ||
(interval.StartInclusive && !intersection.StartInclusive))
{
intervals.Add(interval.Clone(
interval.Start,
interval.StartInclusive,
intersection.Start,
!intersection.StartInclusive));
}
var endToEnd = interval.End.CompareTo(intersection.End);
if (endToEnd != 0 ||
(interval.EndInclusive && !intersection.EndInclusive))
{
intervals.Add(interval.Clone(
intersection.End,
!intersection.EndInclusive,
interval.End,
interval.EndInclusive));
}
return(intervals);
}
