CandidateList.cpp

/**
    Superbubbles
    Copyright (C) 2016 Ritu Kundu, Fatima Vayani, Manal Mohamed, Solon P. Pissis 
    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.
    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.
    You should have received a copy of the GNU General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>.
**/

/** Implements the class CandidateList
*/

#include "CandidateList.hpp"
namespace supbub{

  CandidateList::CandidateList(){
    _front = nullptr;
    _tail = nullptr;
  }

  CandidateList::~CandidateList(){
    while (!empty()) {
      delete_tail();
    }
  }

  Candidate* 
  CandidateList::insert(int64_t ver, bool isEntrance, Candidate* pvsEntrance){
    Candidate* newCand = new Candidate{ver, isEntrance, pvsEntrance, nullptr, _tail};

    // if it's not the first node, set tail to it
    if ( _tail != nullptr) {
      _tail->next = newCand;
      _tail= newCand;
    }
    else{  // if it's first node, set front
      _front = newCand;
      _tail = newCand;
    }
    return newCand;
  }

  Candidate* 
  CandidateList::tail(){
    return _tail;
  }

  Candidate* 
  CandidateList::front(){
    return _front;
  }

  bool
  CandidateList::empty(){
    return (_front==nullptr && _tail==nullptr);
  }

  void
  CandidateList::delete_tail(){
    if (_tail != nullptr) {
      if (_front == _tail) {  // last element in the list
	delete _tail;
	_front = nullptr;
	_tail = nullptr;
      }
      else {
	Candidate* newTail = _tail->pvs;
	delete _tail;
	newTail->next = nullptr;
	_tail = newTail;
      }
    }
  }
   

}// end namespace