RFR [9] 8040747 : Improve performance of IP address parsing

[Claes Redestad]

Hi,

  could I get a review of the following patch to improve IP address 
parsing performance?

http://cr.openjdk.java.net/~mduigou/JDK-8040747/0/webrev/ 
<http://cr.openjdk.java.net/%7Emduigou/JDK-8040747/0/webrev/>
https://bugs.openjdk.java.net/browse/JDK-8040747

  A set of simple JMH benchmarks was created to test all supported and 
some invalid formats. Results show a speed up of ~5-9x for the normal 
cases (9x for simple cases like 0.0.0.0, 5x for longer addresses like 
255.255.255.255), similar boosts for all invalid and rare cases while 
profiling show that the TLAB allocation rates drop significantly using 
the proposed algorithm.

  Note: naturally maintaining compatibility with the standard and 
non-standard formats intently supported by the previous implementation 
(where both 127.0.0.1 and 40000000 would be considered valid IPv4 
addresses), but I've omitted support for the use of explicit signs 
(+127.+0.-0.+1 would work with the old parser) due to reliance on 
Integer.parseInt to parse the octets; a few checks could be added to 
keep supporting these unintended format variants at a small cost.

  /Claes