private static function buildPatterns() {
		if (!is_null(self::$patterns['escape'])) {
			// Patterns have already been built
			return;
		}

		// @codingStandardsIgnoreStart Generic.Files.LineLength.TooLong
		$patterns =& self::$patterns;
		$patterns['escape'] = "(?:{$patterns['unicode']}|\\[^\r\n\f0-9a-f])";
		$patterns['nmstart'] = "(?:[_a-z]|{$patterns['nonAscii']}|{$patterns['escape']})";
		$patterns['nmchar'] = "(?:[_a-z0-9-]|{$patterns['nonAscii']}|{$patterns['escape']})";
		$patterns['ident'] = "-?{$patterns['nmstart']}{$patterns['nmchar']}*";
		$patterns['quantity'] = "{$patterns['num']}(?:\s*{$patterns['unit']}|{$patterns['ident']})?";
		$patterns['possibly_negative_quantity'] = "((?:-?{$patterns['quantity']})|(?:inherit|auto))";
		$patterns['color'] = "(#?{$patterns['nmchar']}+|(?:rgba?|hsla?)\([ \d.,%-]+\))";
		$patterns['url_chars'] = "(?:{$patterns['url_special_chars']}|{$patterns['nonAscii']}|{$patterns['escape']})*";
		$patterns['lookahead_not_open_brace'] = "(?!({$patterns['nmchar']}|\r?\n|\s|#|\:|\.|\,|\+|>|\(|\)|\[|\]|=|\*=|~=|\^=|'[^']*'])*?{)";
		$patterns['lookahead_not_closing_paren'] = "(?!{$patterns['url_chars']}?{$patterns['valid_after_uri_chars']}\))";
		$patterns['lookahead_for_closing_paren'] = "(?={$patterns['url_chars']}?{$patterns['valid_after_uri_chars']}\))";
		$patterns['noflip_single'] = "/({$patterns['noflip_annotation']}{$patterns['lookahead_not_open_brace']}[^;}]+;?)/i";
		$patterns['noflip_class'] = "/({$patterns['noflip_annotation']}{$patterns['chars_within_selector']}})/i";
		$patterns['direction_ltr'] = "/({$patterns['direction']})ltr/i";
		$patterns['direction_rtl'] = "/({$patterns['direction']})rtl/i";
		$patterns['left'] = "/{$patterns['lookbehind_not_letter']}(left){$patterns['lookahead_not_letter']}{$patterns['lookahead_not_closing_paren']}{$patterns['lookahead_not_open_brace']}/i";
		$patterns['right'] = "/{$patterns['lookbehind_not_letter']}(right){$patterns['lookahead_not_letter']}{$patterns['lookahead_not_closing_paren']}{$patterns['lookahead_not_open_brace']}/i";
		$patterns['left_in_url'] = "/{$patterns['lookbehind_not_letter']}(left){$patterns['lookahead_for_closing_paren']}/i";
		$patterns['right_in_url'] = "/{$patterns['lookbehind_not_letter']}(right){$patterns['lookahead_for_closing_paren']}/i";
		$patterns['ltr_in_url'] = "/{$patterns['lookbehind_not_letter']}(ltr){$patterns['lookahead_for_closing_paren']}/i";
		$patterns['rtl_in_url'] = "/{$patterns['lookbehind_not_letter']}(rtl){$patterns['lookahead_for_closing_paren']}/i";
		$patterns['cursor_east'] = "/{$patterns['lookbehind_not_letter']}([ns]?)e-resize/";
		$patterns['cursor_west'] = "/{$patterns['lookbehind_not_letter']}([ns]?)w-resize/";
		$patterns['four_notation_quantity_props'] = "((?:margin|padding|border-width)\s*:\s*)";
		$patterns['four_notation_quantity'] = "/{$patterns['four_notation_quantity_props']}{$patterns['possibly_negative_quantity']}(\s+){$patterns['possibly_negative_quantity']}(\s+){$patterns['possibly_negative_quantity']}(\s+){$patterns['possibly_negative_quantity']}{$patterns['suffix']}/i";
		$patterns['four_notation_color'] = "/((?:-color|border-style)\s*:\s*){$patterns['color']}(\s+){$patterns['color']}(\s+){$patterns['color']}(\s+){$patterns['color']}{$patterns['suffix']}/i";
		// border-radius: <length or percentage>{1,4} [optional: / <length or percentage>{1,4} ]
		$patterns['border_radius'] = '/(border-radius\s*:\s*)' . $patterns['possibly_negative_quantity']
			. '(?:(?:\s+' . $patterns['possibly_negative_quantity'] . ')(?:\s+' . $patterns['possibly_negative_quantity'] . ')?(?:\s+' . $patterns['possibly_negative_quantity'] . ')?)?'
			. '(?:(?:(?:\s*\/\s*)' . $patterns['possibly_negative_quantity'] . ')(?:\s+' . $patterns['possibly_negative_quantity'] . ')?(?:\s+' . $patterns['possibly_negative_quantity'] . ')?(?:\s+' . $patterns['possibly_negative_quantity'] . ')?)?' . $patterns['suffix']
			. '/i';
		$patterns['box_shadow'] = "/(box-shadow\s*:\s*(?:inset\s*)?){$patterns['possibly_negative_quantity']}/i";
		$patterns['text_shadow1'] = "/(text-shadow\s*:\s*){$patterns['possibly_negative_quantity']}(\s*){$patterns['color']}/i";
		$patterns['text_shadow2'] = "/(text-shadow\s*:\s*){$patterns['color']}(\s*){$patterns['possibly_negative_quantity']}/i";
		$patterns['text_shadow3'] = "/(text-shadow\s*:\s*){$patterns['possibly_negative_quantity']}/i";
		$patterns['bg_horizontal_percentage'] = "/(background(?:-position)?\s*:\s*(?:[^:;}\s]+\s+)*?)({$patterns['quantity']})/i";
		$patterns['bg_horizontal_percentage_x'] = "/(background-position-x\s*:\s*)(-?{$patterns['num']}%)/i";
		$patterns['translate_x'] = "/(transform\s*:[^;]*)(translateX\s*\(\s*){$patterns['possibly_negative_quantity']}(\s*\))/i";
		$patterns['translate'] = "/(transform\s*:[^;]*)(translate\s*\(\s*){$patterns['possibly_negative_quantity']}((?:\s*,\s*{$patterns['possibly_negative_quantity']}){0,2}\s*\))/i";
		// @codingStandardsIgnoreEnd
	}