TreeIterator.cpp

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// SPDX-FileCopyrightText: The Bio++ Development Group
//
// SPDX-License-Identifier: CECILL-2.1
 
#include "TreeIterator.h"
 
// imports from bpp-core
using namespace bpp;
using namespace std;
 
 
/******************************************************************************/
 
void TreeIterator::init()
{
  vector<const Node*> nodes = tree_.getNodes();
  for (size_t i = 0; i < nodes.size(); ++i)
  {
    nodeToVisited_[nodes[i]->getId()] = false;
    nodeToSonVisited_[nodes[i]->getId()] = false;
  }
}
 
/******************************************************************************/
 
const Node* TreeIterator::begin()
{
  nodeToVisited_[currNode_->getId()] = true;
  if (currNode_->hasFather())
  {
    nodeToSonVisited_[currNode_->getFatherId()] = true;
    for (size_t i = 0; i < currNode_->getFather()->getNumberOfSons(); ++i)
    {
      if (currNode_ == currNode_->getFather()->getSon(i))
        nodeToLastVisitedSonIndex_[currNode_->getFatherId()] = i;
    }
  }
  return currNode_;
}
 
/******************************************************************************/
 
TreeIterator& TreeIterator::operator++()    // prefix ++
{
  this->next();
  return *this;
}
 
/******************************************************************************/
 
const Node* PostOrderTreeIterator::getLeftMostPredecessor(const Node* startNode)
{
  size_t nextPos = 0;
  if (nodeToSonVisited_[startNode->getId()])
    nextPos = nodeToLastVisitedSonIndex_[startNode->getId()] + 1;
  // if startNode has no predecessors ->  move to him
  if (nextPos >= startNode->getNumberOfSons())
  {
    return startNode;
  }
  const Node* node = startNode->getSon(nextPos);
  while (node->getNumberOfSons() > 0)
  {
    node = node->getSon(0);
  }
  return node;
}
 
/******************************************************************************/
 
const Node* PostOrderTreeIterator::next()
{   // order: (left, right, parent)
    // stop condition: currNode_ is root
  if (!currNode_->hasFather())
  {
    return NULL;
  }
 
  // by the time you visit currNode_, all the nodes in its subtree were already visited
  size_t numOfBrothers =  currNode_->getFather()->getNumberOfSons(); // get the number of brothers of currNode_
  size_t lastVisitedBrotherPos = nodeToLastVisitedSonIndex_[currNode_->getFatherId()]; // since currNode is already visited, its father must have at least one visited son (which is currNode_)
  // if all the brothers were already visited -> now visit the father
  if (lastVisitedBrotherPos == numOfBrothers - 1)
  {
    currNode_ = currNode_->getFather();
  }
  // else -> visit the leftmost predecessor next brother on the list
  else
  {
    size_t nextSiblingPos = lastVisitedBrotherPos + 1;
    currNode_ = currNode_->getFather()->getSon(nextSiblingPos); // the next brother is not visited yet if its has a non-visited leftmost predecessor
    currNode_ = getLeftMostPredecessor(currNode_);
  }
 
  // update the returned node to be visited and its father's last visited son, if needed
  nodeToVisited_[currNode_->getId()] = true;
  if (currNode_->hasFather())
  {
    if (!nodeToSonVisited_[currNode_->getFatherId()])
    {
      nodeToSonVisited_[currNode_->getFatherId()] = true;
      nodeToLastVisitedSonIndex_[currNode_->getFatherId()] = 0;
    }
    else
    {
      nodeToLastVisitedSonIndex_[currNode_->getFatherId()] = nodeToLastVisitedSonIndex_[currNode_->getFatherId()] + 1;
    }
  }
  return currNode_;
}
 
/******************************************************************************/
 
const Node* PreOrderTreeIterator::next()
{   // order: (parent, left, right)
  vector<int> leafIds = tree_.getLeavesId();
  bool hasVisitedSons = nodeToSonVisited_[currNode_->getId()];
  size_t numOfSons = currNode_->getNumberOfSons();
 
  // stop condition: the node is the rightmost leaf of the tree
  if (currNode_->getId() == leafIds[leafIds.size() - 1])
  {
    return NULL;
  }
 
  // by the time you visit currNode_, all its ancestors and left brothers (if exist) were already visited
  if (!hasVisitedSons && numOfSons > 0)
  {
    currNode_ = currNode_->getSon(0); // this somehow modifies the value of nodeToSonVisited_[currNode_->getFatherId()] to true... how?
  }
  // as long as there are still sons to visit -> visit the leftmost unvisited son
  else if (hasVisitedSons && nodeToLastVisitedSonIndex_[currNode_->getId()] < numOfSons - 1)
  {
    // if this point is reached, the current node already has visited sons, or it has no sons at all and we are done
    currNode_ = currNode_->getSon(nodeToLastVisitedSonIndex_[currNode_->getId()] + 1);
    // else -> traverse to the leftmost brother which is right to currNode_ (also occurs when currNode has no sons
  }
  else
  {
    currNode_ = currNode_->getFather();
    size_t lastVisitedSonPos = nodeToLastVisitedSonIndex_[currNode_->getId()]; // the father of the original currNode_ must have at least one visited child which is the original currNode_
    numOfSons = currNode_->getNumberOfSons();
    while (lastVisitedSonPos == numOfSons - 1)
    {
      currNode_ = currNode_->getFather(); // the father node must have visited sons as the currNode is a visited son of his
      lastVisitedSonPos = nodeToLastVisitedSonIndex_[currNode_->getId()];
      numOfSons = currNode_->getNumberOfSons();
    }
    currNode_ = currNode_->getSon(lastVisitedSonPos + 1);    // need to remove +1??
  }
  // update the returned node to be visited and its father's last visited son, if needed
  if (currNode_->hasFather())
  {
    if (nodeToSonVisited_[currNode_->getFatherId()])
      nodeToLastVisitedSonIndex_[currNode_->getFatherId()] = nodeToLastVisitedSonIndex_[currNode_->getFatherId()] + 1;
    else
    {
      nodeToSonVisited_[currNode_->getFatherId()] = true;
      nodeToLastVisitedSonIndex_[currNode_->getFatherId()] = 0;
    }
  }
  nodeToVisited_[currNode_->getId()] = true;
  return currNode_;
}
 
/******************************************************************************/
 
const Node* InOrderTreeIterator::doStep(const Node* node)
{
  // if the node has unvisited left sons -> visit the leftmost unvisited son
  size_t lastVisitedSon = 0; // jdutheil on 02/10/24: The init value is never used, but there to present a compilation warning.
  if (nodeToSonVisited_[node->getId()])
    lastVisitedSon = nodeToLastVisitedSonIndex_[node->getId()];
  size_t numOfSons = node->getNumberOfSons();
  bool is_visited =  nodeToVisited_[node->getId()];
 
  // if the node has unvisited left sons - go to the leftmost unvisited son
  if (!nodeToSonVisited_[node->getId()] && numOfSons > 0)
  {
    return node->getSon(0);
  }
  else if (nodeToSonVisited_[node->getId()] && lastVisitedSon < static_cast<size_t>(floor(numOfSons / 2) - 1))
  {
    return node->getSon(lastVisitedSon + 1);
  }
 
  // if the node last visited its last left son or is a not yet visited leaf / parent of a single node -> go to it
  else if (numOfSons > 1 && lastVisitedSon == static_cast<size_t>(floor(numOfSons / 2) - 1) && !is_visited)
  {
    return node;
  }
 
  // if the node has unvisited right sons -> go to the leftmost unvisited right son
  else if (nodeToSonVisited_[node->getId()] && lastVisitedSon < numOfSons - 1)
  {
    return node->getSon(lastVisitedSon + 1);
  }
 
  // else - the entire subtree of the node has been scanned - move to its father
  else
  {
    return node->getFather();
  }
}
 
 
/******************************************************************************/
 
const Node* InOrderTreeIterator::next()
{   // order: (left (0,..,n/2-1), parent, right (n/2,....,n))
  vector<int> leafIds = tree_.getLeavesId();
 
  // stop condition: the node is the rightmost leaf of the tree
  if (currNode_->getId() == leafIds[leafIds.size() - 1])
  {
    return NULL;
  }
 
  // while curNode still has unvisited left sons -> do another step
  while (nodeToVisited_[currNode_->getId()]
      || (!nodeToSonVisited_[currNode_->getId()] && !currNode_->isLeaf()) || (nodeToSonVisited_[currNode_->getId()] && nodeToLastVisitedSonIndex_[currNode_->getId()] < static_cast<size_t>(floor(currNode_->getNumberOfSons() / 2) - 1) && !currNode_->isLeaf()))
  {
    currNode_ = doStep(currNode_);
  }
 
  // update the returned node to be visited and its father's last visited son, if needed
  if (currNode_->hasFather())
  {
    if (nodeToSonVisited_[currNode_->getFatherId()])
      nodeToLastVisitedSonIndex_[currNode_->getFatherId()] = nodeToLastVisitedSonIndex_[currNode_->getFatherId()] + 1;
    else
    {
      nodeToSonVisited_[currNode_->getFatherId()] = true;
      nodeToLastVisitedSonIndex_[currNode_->getFatherId()] = 0;
    }
  }
  nodeToVisited_[currNode_->getId()] = true;
  return currNode_;
}