Simplified IPv6 regex per comment

* We already require PHP 5.3.2, which includes PCRE 7.2+.
  PHP 5.2.4 includes PCRE 7.2 per http://php.net/ChangeLog-5.php.

Change-Id: Ie9c1a0a93bef30a3a67e0140e621814351f8cea1

diff --git a/includes/IP.php b/includes/IP.php
index fc76310..73834a5 100644 (file)
--- a/includes/IP.php
+++ b/includes/IP.php
@@ -39,18 +39,11 @@ define( 'RE_IPV6_ADD',
                ':(?::|(?::' . RE_IPV6_WORD . '){1,7})' .
        '|' . // ends with "::" (except "::")
                RE_IPV6_WORD . '(?::' . RE_IPV6_WORD . '){0,6}::' .
-       '|' . // contains one "::" in the middle, ending in "::WORD"
-               RE_IPV6_WORD . '(?::' . RE_IPV6_WORD . '){0,5}' . '::' . RE_IPV6_WORD .
-       '|' . // contains one "::" in the middle, not ending in "::WORD" (regex for PCRE 4.0+)
-               RE_IPV6_WORD . '(?::(?P<abn>:(?P<iabn>))?' . RE_IPV6_WORD . '(?!:(?P=abn))){1,5}' .
-                       ':' . RE_IPV6_WORD . '(?P=iabn)' .
-               // NOTE: (?!(?P=abn)) fails iff "::" used twice; (?P=iabn) passes iff a "::" was found.
+       '|' . // contains one "::" in the middle (the ^ makes the test fail if none found)
+               RE_IPV6_WORD . '(?::((?(-1)|:))?' . RE_IPV6_WORD . '){1,6}(?(-2)|^)' .
        '|' . // contains no "::"
                RE_IPV6_WORD . '(?::' . RE_IPV6_WORD . '){7}' .
        ')'
-       // NOTE: With PCRE 7.2+, we can combine the two '"::" in the middle' cases into:
-       //              RE_IPV6_WORD . '(?::((?(-1)|:))?' . RE_IPV6_WORD . '){1,6}(?(-2)|^)'
-       // This also improves regex concatenation by using relative references.
 );
 // An IPv6 block is an IP address and a prefix (d1 to d128)
 define( 'RE_IPV6_BLOCK', RE_IPV6_ADD . '\/' . RE_IPV6_PREFIX );