bbp_make_urls_clickable( string $text = '' )

function bbp_make_urls_clickable( $text = '' ) {
	$url_clickable = '~
		([\\s(<.,;:!?])                                # 1: Leading whitespace, or punctuation
		(                                              # 2: URL
			[\\w]{1,20}+://                            # Scheme and hier-part prefix
			(?=\S{1,2000}\s)                           # Limit to URLs less than about 2000 characters long
			[\\w\\x80-\\xff#%\\~/@\\[\\]*(+=&$-]*+     # Non-punctuation URL character
			(?:                                        # Unroll the Loop: Only allow puctuation URL character if followed by a non-punctuation URL character
				[\'.,;:!?)]                            # Punctuation URL character
				[\\w\\x80-\\xff#%\\~/@\\[\\]*(+=&$-]++ # Non-punctuation URL character
			)*
		)
		(\)?)                                          # 3: Trailing closing parenthesis (for parethesis balancing post processing)
	~xS';

	// The regex is a non-anchored pattern and does not have a single fixed starting character.
	// Tell PCRE to spend more time optimizing since, when used on a page load, it will probably be used several times.
	return preg_replace_callback( $url_clickable, '_make_url_clickable_cb', $text );
}