':(?::|(?::' . 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 );