static uint8_t compute_meta_length_after_function(int function,
                                                  msg_type_t msg_type)
{
    int length;

    if (msg_type == MSG_INDICATION) {
        if (function <= MODBUS_FC_WRITE_SINGLE_REGISTER) {
            length = 4;
        } else if (function == MODBUS_FC_WRITE_MULTIPLE_COILS ||
                   function == MODBUS_FC_WRITE_MULTIPLE_REGISTERS) {
            length = 5;
        } else if (function == MODBUS_FC_MASK_WRITE_REGISTER) {
            length = 6;
        } else if (function == MODBUS_FC_WRITE_AND_READ_REGISTERS) {
            length = 9;
        } else {
            /* MODBUS_FC_READ_EXCEPTION_STATUS, MODBUS_FC_REPORT_SLAVE_ID */
            length = 0;
        }
    } else {
        /* MSG_CONFIRMATION */
        switch (function) {
        case MODBUS_FC_WRITE_SINGLE_COIL:
        case MODBUS_FC_WRITE_SINGLE_REGISTER:
        case MODBUS_FC_WRITE_MULTIPLE_COILS:
        case MODBUS_FC_WRITE_MULTIPLE_REGISTERS:
            length = 4;
            break;
        case MODBUS_FC_MASK_WRITE_REGISTER:
            length = 6;
            break;
        default:
            length = 1;
        }
    }

    return length;
}
Unknown