for saving on a cell which is completely unmodified. One of these
was due to the BPlane implementation, which forces an instance to be
deleted and re-placed on a bounding box recomputation, which should
not, in that case, be considered a modification. Another always runs
DRC on a subcell upon reading rather than relying on any checkplane
entries in the file itself; and the last one marking the timestamp
as modified stemming from an attempt to correct an O(N^2) check to
O(N). All three cases have now been corrected.
since the edit box was undefined in the code, potentially this
fixes any number of random problems that might be seen with the
"port" command. Also: Modified the cell bounding box recalculation
so that it does not continually update a parent cell on every
addition of a child cell but only once for each child cell found.
This greatly reduces the time for GDS file input in the case of
large arrays of cells.
Tim Edwards