_wp_specialchars

Source code

function _wp_specialchars( $string, $quote_style = ENT_NOQUOTES, $charset = false, $double_encode = false ) {

	$string = (string) $string;



	if ( 0 === strlen( $string ) )

		return '';



	// Don't bother if there are no specialchars - saves some processing

	if ( ! preg_match( '/[&<>"\']/', $string ) )

		return $string;



	// Account for the previous behaviour of the function when the $quote_style is not an accepted value

	if ( empty( $quote_style ) )

		$quote_style = ENT_NOQUOTES;

	elseif ( ! in_array( $quote_style, array( 0, 2, 3, 'single', 'double' ), true ) )

		$quote_style = ENT_QUOTES;



	// Store the site charset as a static to avoid multiple calls to wp_load_alloptions()

	if ( ! $charset ) {

		static $_charset;

		if ( ! isset( $_charset ) ) {

			$alloptions = wp_load_alloptions();

			$_charset = isset( $alloptions['blog_charset'] ) ? $alloptions['blog_charset'] : '';

		}

		$charset = $_charset;

	}



	if ( in_array( $charset, array( 'utf8', 'utf-8', 'UTF8' ) ) )

		$charset = 'UTF-8';



	$_quote_style = $quote_style;



	if ( $quote_style === 'double' ) {

		$quote_style = ENT_COMPAT;

		$_quote_style = ENT_COMPAT;

	} elseif ( $quote_style === 'single' ) {

		$quote_style = ENT_NOQUOTES;

	}



	// Handle double encoding ourselves

	if ( $double_encode ) {

		$string = @htmlspecialchars( $string, $quote_style, $charset );

	} else {

		// Decode &amp; into &

		$string = wp_specialchars_decode( $string, $_quote_style );



		// Guarantee every &entity; is valid or re-encode the &

		$string = wp_kses_normalize_entities( $string );



		// Now re-encode everything except &entity;

		$string = preg_split( '/(&#?x?[0-9a-z]+;)/i', $string, -1, PREG_SPLIT_DELIM_CAPTURE );



		for ( $i = 0; $i < count( $string ); $i += 2 )

			$string[$i] = @htmlspecialchars( $string[$i], $quote_style, $charset );



		$string = implode( '', $string );

	}



	// Backwards compatibility

	if ( 'single' === $_quote_style )

		$string = str_replace( "'", ''', $string );



	return $string;

}