_wp_scrub_utf8_fallback( string $bytes ): string

287function _wp_scrub_utf8_fallback( string $bytes ): string {288	$bytes_length   = strlen( $bytes );289	$next_byte_at   = 0;290	$was_at         = 0;291	$invalid_length = 0;292	$scrubbed       = '';293 294	while ( $next_byte_at <= $bytes_length ) {295		_wp_scan_utf8( $bytes, $next_byte_at, $invalid_length );296 297		if ( $next_byte_at >= $bytes_length ) {298			if ( 0 === $was_at ) {299				return $bytes;300			}301 302			return $scrubbed . substr( $bytes, $was_at, $next_byte_at - $was_at - $invalid_length );303		}304 305		$scrubbed .= substr( $bytes, $was_at, $next_byte_at - $was_at );306		$scrubbed .= "\u{FFFD}";307 308		$next_byte_at += $invalid_length;309		$was_at        = $next_byte_at;310	}311 312	return $scrubbed;313}