Another RFC: regex in libiberty
Jim Blandy
jimb@zwingli.cygnus.com
Tue Jun 12 06:48:00 GMT 2001
Jim Blandy <jimb@cygnus.com> writes:
> To generate every possible match, you have to choose every possible
> way to divide up those twenty a's amongst six .* patterns. I think
> this is 20 choose 5, or 1.9 million, matches you have to try. In
> general, I think the time to match POSIXly can increase exponentially
> in the length of your regexp, given a long enough data string.
20 choose 5 is, of course, only 15504, not 1.9 million. Oops.
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