All the sources codespage 66

if (!function_exists("GetSQLValueString"))
{
	function GetSQLValueString($theValue, $theType = null, $theDefinedValue = "", $theNotDefinedValue = "")
	{
		$theValue = get_magic_quotes_gpc() ? stripslashes($theValue) : $theValue;
		$theValue = function_exists("mysql_real_escape_string") ? mysql_real_escape_string($theValue) : mysql_escape_string($theValue);
		switch ($theType) {
			case "text":
				$theValue = ($theValue != "") ? "'" . $theValue . "'" : "NULL";
			break;      
			case "long":
			case "int":
				$theValue = ($theValue != "") ? intval($theValue) : "NULL";
			break;
			case "double":
				$theValue = ($theValue != "") ? "'" . doubleval($theValue) . "'" : "NULL";
				break;
			case "date":
				$theValue = ($theValue != "") ? "'" . $theValue . "'" : "NULL";
				break;
			case "defined":
				$theValue = ($theValue != "") ? $theDefinedValue : $theNotDefinedValue;
				break;
		}
		return $theValue;
	}
}

// . . .
	return $this->boolean((bool)$data);
}
	
/**
 * Translates between PHP boolean values and Database (faked) boolean values
 *
 * @param mixed $data Value to be translated
 * @return mixed Converted boolean value
 * @access public
 */
	function boolean($data) {
		if ($data === true || $data === false) {
			if ($data === true) {
				return "true";
			}
			return "false";
		} else {
			return !empty($data);
		}
	}

return void;