switch_node.h

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/* Copyright (C) 2020-2022 Davide Faconti -  All Rights Reserved
*
*   Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"),
*   to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense,
*   and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
*   The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
*
*   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
*   FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
*   WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/
 
#pragma once
 
#include "behaviortree_cpp/control_node.h"
 
namespace BT
{
namespace details
{
 
bool CheckStringEquality(const std::string& v1, const std::string& v2,
                         const ScriptingEnumsRegistry* enums);
}
 
template <size_t NUM_CASES>
class SwitchNode : public ControlNode
{
public:
  SwitchNode(const std::string& name, const BT::NodeConfig& config);
 
  virtual ~SwitchNode() override = default;
 
  void halt() override;
 
  static PortsList providedPorts();
 
private:
  int running_child_;
  std::vector<std::string> case_keys_;
  virtual BT::NodeStatus tick() override;
};
 
//-----------------------------------------------
//-----------------------------------------------
 
template <size_t NUM_CASES>
inline SwitchNode<NUM_CASES>::SwitchNode(const std::string& name,
                                         const NodeConfig& config)
  : ControlNode::ControlNode(name, config), running_child_(-1)
{
  setRegistrationID("Switch");
  for(unsigned i = 1; i <= NUM_CASES; i++)
  {
    case_keys_.push_back(std::string("case_") + std::to_string(i));
  }
}
 
template <size_t NUM_CASES>
inline void SwitchNode<NUM_CASES>::halt()
{
  running_child_ = -1;
  ControlNode::halt();
}
 
template <size_t NUM_CASES>
inline PortsList SwitchNode<NUM_CASES>::providedPorts()
{
  static PortsList provided_ports = []() {
    PortsList ports;
    ports.insert(BT::InputPort<std::string>("variable"));
    for(unsigned i = 1; i <= NUM_CASES; i++)
    {
      auto key = std::string("case_") + std::to_string(i);
      ports.insert(BT::InputPort<std::string>(key));
    }
    return ports;
  }();
 
  return provided_ports;
}
 
template <size_t NUM_CASES>
inline NodeStatus SwitchNode<NUM_CASES>::tick()
{
  if(childrenCount() != NUM_CASES + 1)
  {
    throw LogicError("Wrong number of children in SwitchNode; "
                     "must be (num_cases + default)");
  }
 
  std::string variable;
  std::string value;
  int match_index = int(NUM_CASES);  // default index;
 
  // no variable? jump to default
  if(getInput("variable", variable))
  {
    // check each case until you find a match
    for(int index = 0; index < int(NUM_CASES); ++index)
    {
      const std::string& case_key = case_keys_[index];
      if(getInput(case_key, value))
      {
        if(details::CheckStringEquality(variable, value, this->config().enums.get()))
        {
          match_index = index;
          break;
        }
      }
    }
  }
 
  // if another one was running earlier, halt it
  if(running_child_ != -1 && running_child_ != match_index)
  {
    haltChild(running_child_);
  }
 
  auto& selected_child = children_nodes_[match_index];
  NodeStatus ret = selected_child->executeTick();
  if(ret == NodeStatus::SKIPPED)
  {
    // if the matching child is SKIPPED, should I jump to default or
    // be SKIPPED myself? Going with the former, for the time being.
    running_child_ = -1;
    return NodeStatus::SKIPPED;
  }
  else if(ret == NodeStatus::RUNNING)
  {
    running_child_ = match_index;
  }
  else
  {
    resetChildren();
    running_child_ = -1;
  }
  return ret;
}
 
}  // namespace BT