presto-main/src/main/java/io/prestosql/sql/planner/DomainTranslator.java/DomainTranslator/floorValue
class DomainTranslator:        private Optional<Object> floorValue(Type fromType, Type toType, Object value)
        {
            return getSaturatedFloorCastOperator(fromType, toType)
                    .map((operator) -> functionInvoker.invoke(operator, session.toConnectorSession(), value));
        }