/**
* Initialize the regex for this instance.
*/
public static function initializeRegex()
{
self::$regex = <<<END_OF_REGEX
(?xi)
(?:\\b|^)
( # Capture 1: entire matched URL
(
(?:[a-z][\\w-+]{0,19})?:/{1,3} # URL protocol and colon followed by 1-3
# slashes, or just colon and slashes (://)
| # - or -
(?<!\\.)www\\d{0,3}\\. # "www.", "www1.", "www2." … "www999."
# without a leading period
| # - or -
[a-z0-9.\\-]+\\.[a-z]{2,4}/ # looks like domain name followed by a slash
)
(?: # One or more:
[^\\s()<>\\[\\]]+ # Run of non-space, non-()<>
(?<![\\s`!()\\[\\]{};:\\'".,<>?«»“”‘’]{2}) # that is not followed by two or more
# punct chars that indicate end-of-url
| # - or -
\\(([^\\s()<>]+|(\\([^\\s()<>]+\\)))*\\) # balanced parens, up to 2 levels
)+
(?: # End with:
\\(([^\\s()<>]+|(\\([^\\s()<>]+\\)))*\\) # balanced parens, up to 2 levels
| # - or -
[^\\s`!()\\[\\]{};:\\'".,<>?«»“”‘’] # not a space or one of these punct
# chars
)
)
END_OF_REGEX;
}
