parse unix-style difference reporting

From: Liang (leo2002chen_at_hotmail.com)
Date: 12/30/03 

Date: Tue, 30 Dec 2003 10:00:39 +0800

Hi all,

I want to diff two files or two versions of one file, and parse the output
to find a summary of how many lines of replacement/addition/deletion in the
two files.

Known from diff/cleardiff, the output has a style like:
15a16, 15,17d3, 18c19,21 etc.

Anyone know how to parse these output to generate a summary?

Thanks in advance,
Liang