regex status report #2

[Gabor Kovesdan]

Hi,

I've been testing more the code and I found a bug that in my code 
concerning REG_STARTEND that I added last week. I fixed it. I looked at 
NetBSD's code to see if they have any local improvements. I've merged 
REG_PEND support but they don't have anything else.
In general, I see that TRE is a mature regex implementation with good 
POSIX-conformance but its performance is not always satisfying. So I've 
used gprof to check where the processing time is spent and I'll continue 
investigationg on how to improve the performance. Basically, there are 
two ways;
- improving the TRE matching code itself
- using heuristics and shortcuts; e.g. use fixed string matching to 
detect possibly matching context or detecting if the pattern is simple 
and can use a faster algorithm instead of heavy-weight pattern matching.

Gabor