public IEnumerator <(T[] _arr, int _fromIdx, int _toIdx, int _itIdx, int _absIdx)> Get2DEnumerator(int fromIdx,
int toIdx)
{
if (toIdx < fromIdx)
{
throw new ArgumentException("To cannot be lower or equal to From");
}
if (fromIdx < Lower)
{
throw new ArgumentException("From cannot be lower than Lower bound");
}
if (fromIdx > Upper)
{
throw new ArgumentException("From cannot be greater or equal to Upper bound");
}
if (toIdx < Lower)
{
throw new ArgumentException("To cannot be lower or equal to Upper bound");
}
if (toIdx > Upper)
{
throw new ArgumentException("To cannot be greater than Upper bound");
}
int remaining = toIdx - fromIdx + 1;
// Fast-forward to first matching array
int arrIdx = Segments.BinarySearch(
new SubSegment(null,
fromIdx),
new PositionalBoundsComparer()
);
fromIdx -= Segments[arrIdx].Lower;
do
{
SubSegment sSeg = Segments[arrIdx];
T[] arr = sSeg.Array;
toIdx = Math.Min(arr.Length,
remaining + fromIdx) - 1;
yield return(arr, fromIdx, toIdx, sSeg.Lower - Lower + fromIdx, sSeg.Lower + fromIdx);
int lastLength = toIdx - fromIdx + 1;
remaining -= lastLength;
arrIdx++;
fromIdx = 0;
} while (remaining > 0);
}