/// <summary>
/// Returns a sub-array from the given input array, based on the indexes
/// returned by the provided range instance.
/// For example, if the Range elements are [3,2,1], then this method
/// will return an array consisting of the elements 3,2,1 from the
/// input array.
/// If the input array is null, this method returns null.
/// If the input range is null or empty, this method returns an empty array.
/// If the elements of the range are outside the array bounds, it throws
/// an ArgumentOutOfRangeException
/// </summary>
public QArray <T> Slice(QRange range)
{
if (range == null)
{
// Debug.Assert(false, $"Trying to slice an array with a null range");
return(new QArray <T>());
}
if (range.IsEmpty)
{
return(new QArray <T>());
}
long rangeCount = 1 + (range.End - range.Start) / range.Step;
long rangeEnd = range.Start + (rangeCount - 1) * range.Step;
// Make sure the slice fits
if ((range.Start >= Length) || (range.Start < 0) || (rangeEnd >= Length) || (rangeEnd < 0))
{
throw new ArgumentOutOfRangeException();
}
if (range.Start == range.End)
{
return(new QArray <T>(this[range.Start]));
}
long newStart = ConvertIndex(range.Start);
long newStep = range.Step * step;
long newCount = rangeCount;
QArray <T> result = new QArray <T>(this);
result.start = newStart;
result.step = newStep;
result.Length = newCount;
return(result);
}
IQArray <T> IQArray <T> .Slice(QRange range) => Slice(range);