On 7/7/2011 5:58 AM, /dev/rob0 wrote:
> On Thu, Jul 07, 2011 at 03:36:02AM -0500, Stan Hoeppner wrote:
>> I received a request to ignore IPv4 addresses as well in order to
>> improve performance. But given the extensive IF loops it seems
>> we'd only save something like a few picoseconds of CPU time (<30
>> expressions processed). If that's actually critical I could add
>> something like
>>
>> /^([0-9]{1,3}\.){3}[0-9]{1,3}$/ DUNNO
>>
>> Crude testing with postmap -q shows this matches only a naked
>> dotted quad, but I'd rather not unleash it without more thorough
>> testing, or confirmation from resident regex gurus that this will
>> work as intended. Many rDNS strings contain a dotted quad, so we
>> want to return DUNNO only for a naked dotted quad.
>
> The anchors at both ends mean you are safe. You start with ^ and end
> with $, so nothing else can sneak in between those.
>
> A simpler expression to accomplish the same thing:
> /^[0-9\.]$/ DUNNO
> In English, that says: match a string which contains nothing but
> numerals and dots. It matches nonsense strings such as "...", but
> would be safe as per your intent to only match bare IP addresses.
With that being right anchored, the last character it attempts to match
is a dot, no? See a problem there?
--
Stan
