/// <summary>
/// Creates a new span over the portion of the target array beginning
/// at 'start' index and ending at 'end' index (exclusive).
/// </summary>
/// <param name="array">The target array.</param>
/// <param name="start">The index at which to begin the span.</param>
/// <param name="length">The number of items in the span.</param>
/// <exception cref="System.ArgumentException">
/// Thrown if the 'array' parameter is null.
/// </exception>
/// <exception cref="System.ArgumentOutOfRangeException">
/// Thrown when the specified start or end index is not in range (<0 or >&eq;length).
/// </exception>
public Span(T[] array, int start, int length)
{
Contract.Requires(array != null);
Contract.RequiresInInclusiveRange(start, array.Length);
Contract.RequiresNonNegative(length);
Contract.RequiresInInclusiveRange(start + length, array.Length);
if (start < array.Length)
{
_object = array;
_offset = new UIntPtr(
(uint)(SpanHelpers <T> .OffsetToArrayData + (start * PtrUtils.SizeOf <T>())));
Length = length;
}
else
{
_object = null;
_offset = UIntPtr.Zero;
Length = 0;
}
}