Identfying area to place doubled contact

Hello,

I am working on script to double contacts in a layout. My logic is as
follows:

1. I have the width and length of the doubled contact.
The width of the contact is the same but the lenght is different
from the
single contact.

2. Identify Contacts in Layout.
3. Take one contact at a time
4. Identify an area where a doubled contact can be placed.*(Currently
only along the X axis. )
The area has the width of the existing singel contact with the Y
co-ords being the same as the contact I am trying to double.


5. Identify the left edge of the area to the left of the original
contact.
6. Identify the right edge of the ares to the right of the original
contact.
7. Place the doubled contact in the centre of the marked area.


The problem is to find the left and right edges of the area.
I dont want to search incrementally (to the left and right) from the
existing contact as this would be too time consuming in the case of
huge layouts.


I hope I have made myself clear. Any help would be greatly
appreciated.I am pretty new to SKILL and I am finding it difficult to
foresee the issues I have to face during the doubling process. I have
made quite a bit (albeit slowly) of progress in identifying the
contacts.