DisjointElement.cpp

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// Mantid Repository : https://github.com/mantidproject/mantid
//
// Copyright © 2018 ISIS Rutherford Appleton Laboratory UKRI,
//   NScD Oak Ridge National Laboratory, European Spallation Source,
//   Institut Laue - Langevin & CSNS, Institute of High Energy Physics, CAS
// SPDX - License - Identifier: GPL - 3.0 +
#include "MantidCrystal/DisjointElement.h"
 
namespace Mantid::Crystal {
 
DisjointElement::DisjointElement() : m_parent(this), m_rank(0), m_id(-1) {}
 
DisjointElement::DisjointElement(const int id) : m_parent(this), m_rank(0), m_id(id) {}
 
DisjointElement::DisjointElement(const DisjointElement &other)
    : m_parent(other.m_parent), m_rank(other.m_rank), m_id(other.m_id) {
 
  // Don't point to copy object as parent if copy object is it's own parent.
  if (other.m_parent == &other) {
    m_parent = this;
  }
}
 
DisjointElement &DisjointElement::operator=(const DisjointElement &other) {
  if (this != &other) {
    m_parent = other.m_parent;
    m_rank = other.m_rank;
    m_id = other.m_id;
  }
  return *this;
}
 
int DisjointElement::getId() const { return m_id; }
 
DisjointElement *DisjointElement::getParent() const { return m_parent; }
 
int DisjointElement::compress() {
  DisjointElement *temp = m_parent;
  while (temp->hasParent()) {
    temp = temp->getParent();
  }
  m_parent = temp;
  return m_parent->getRoot();
}
 
bool DisjointElement::hasParent() const { return m_parent != this; }
 
int DisjointElement::getRoot() const {
  if (m_parent == this) {
    return m_id;
  } else {
    return m_parent->getRoot();
  }
}
 
void DisjointElement::setParent(DisjointElement *other) { m_parent = other; }
 
int DisjointElement::incrementRank() { return ++m_rank; }
 
int DisjointElement::getRank() const { return m_rank; }
 
bool DisjointElement::isEmpty() const { return m_id == -1; }
 
void DisjointElement::unionWith(DisjointElement *other) {
 
  if (other->getRoot() != this->getRoot()) // Check sets do not already have the
                                           // same root before continuing
  {
    this->compress();
    other->compress();
 
    DisjointElement *x = this->getParent();
    DisjointElement *y = other->getParent();
 
    if (x->getRank() > y->getRank()) {
      y->setParent(x);
    } else {
      x->setParent(y);
      if (x->getRank() == y->getRank()) {
        y->incrementRank();
      }
    }
  }
}
 
void unionElements(DisjointElement *a, DisjointElement *b) { a->unionWith(b); }
 
void DisjointElement::setId(int id) { m_id = id; }
 
} // namespace Mantid::Crystal