If restoration professionals work with the wet floor before buckling occurs the floor can usually be saved with no damage whatsoever, as the only briefly wet cupped floor will flatten as it dries and the finish typically does not have to be redone.
However, buckling typically occurs within the first day or day and a half, as nails begin pulling through the wet floor boards, inevitably signifying severe damage is being done.
Floors subjected to moisture for longer than a day and a half have good chance at flattening out the cupping, but there is still an increasing possibility for cupped boards. These soaked floors will typically dry out well, but will almost certainly need to be refinished.
Remember, prompt action is the key as flooring that has been wet longer is less likely to be fully recoverable, and wood flooring soaked for more than three days poses such a more difficult dry out process that it has far less of a chance for successful restoration in place.