collect.cxx

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  }

  while (lastIndex > index) {
    lastElement = lastElement->prev;
    --lastIndex;
  }

  return PTrue;
}


PListElement::PListElement(PObject * theData)
{
  next = prev = NULL;
  data = theData;
}


///////////////////////////////////////////////////////////////////////////////

PAbstractSortedList::PAbstractSortedList()
{
  info = new PSortedListInfo;
  PAssert(info != NULL, POutOfMemory);
}


PSortedListInfo::PSortedListInfo()
{
  root = &nil;
  nil.parent = nil.left = nil.right = &nil;
  nil.subTreeSize = 0;
  nil.colour = Element::Black;
  nil.data = NULL;
}


void PAbstractSortedList::DestroyContents()
{
  RemoveAll();
  delete info;
  info = NULL;
}


void PAbstractSortedList::CopyContents(const PAbstractSortedList & list)
{
  info = list.info;
}


void PAbstractSortedList::CloneContents(const PAbstractSortedList * list)
{
  PSortedListInfo * otherInfo = list->info;

  info = new PSortedListInfo;
  PAssert(info != NULL, POutOfMemory);
  reference->size = 0;

  // Have to do this in this manner rather than just doing a for() loop
  // as "this" and "list" may be the same object and we just changed info in
  // "this" so we need to use the info in "list" saved previously.
  Element * element = otherInfo->OrderSelect(otherInfo->root, 1);
  while (element != &otherInfo->nil) {
    Append(element->data->Clone());
    element = otherInfo->Successor(element);
  }
}


PBoolean PAbstractSortedList::SetSize(PINDEX)
{
  return PTrue;
}


PObject::Comparison PAbstractSortedList::Compare(const PObject & obj) const
{
  PAssert(PIsDescendant(&obj, PAbstractSortedList), PInvalidCast);
  Element * elmt1 = info->root;
  while (elmt1->left != &info->nil)
    elmt1 = elmt1->left;

  Element * elmt2 = ((const PAbstractSortedList &)obj).info->root;
  while (elmt2->left != &info->nil)
    elmt2 = elmt2->left;

  while (elmt1 != &info->nil && elmt2 != &info->nil) {
    if (elmt1 == &info->nil)
      return LessThan;
    if (elmt2 == &info->nil)
      return GreaterThan;
    if (*elmt1->data < *elmt2->data)
      return LessThan;
    if (*elmt1->data > *elmt2->data)
      return GreaterThan;
    elmt1 = info->Successor(elmt1);
    elmt2 = info->Successor(elmt2);
  }
  return EqualTo;
}


PINDEX PAbstractSortedList::Append(PObject * obj)
{
  if (PAssertNULL(obj) == NULL)
    return P_MAX_INDEX;

  Element * z = new Element;
  z->parent = z->left = z->right = &info->nil;
  z->colour = Element::Black;
  z->subTreeSize = 1;
  z->data = obj;

  Element * x = info->root;
  Element * y = &info->nil;
  while (x != &info->nil) {
    x->subTreeSize++;
    y = x;
    x = *z->data < *x->data ? x->left : x->right;
  }
  z->parent = y;
  if (y == &info->nil)
    info->root = z;
  else if (*z->data < *y->data)
    y->left = z;
  else
    y->right = z;

  PSortedListElement * lastElement = x = z;
  PINDEX lastIndex;

  x->colour = Element::Red;
  while (x != info->root && x->parent->colour == Element::Red) {
    if (x->parent == x->parent->parent->left) {
      y = x->parent->parent->right;
      if (y->colour == Element::Red) {
        x->parent->colour = Element::Black;
        y->colour = Element::Black;
        x->parent->parent->colour = Element::Red;
        x = x->parent->parent;
      }
      else {
        if (x == x->parent->right) {
          x = x->parent;
          LeftRotate(x);
        }
        x->parent->colour = Element::Black;
        x->parent->parent->colour = Element::Red;
        RightRotate(x->parent->parent);
      }
    }
    else {
      y = x->parent->parent->left;
      if (y->colour == Element::Red) {
        x->parent->colour = Element::Black;
        y->colour = Element::Black;
        x->parent->parent->colour = Element::Red;
        x = x->parent->parent;
      }
      else {
        if (x == x->parent->left) {
          x = x->parent;
          RightRotate(x);
        }
        x->parent->colour = Element::Black;
        x->parent->parent->colour = Element::Red;
        LeftRotate(x->parent->parent);
      }
    }
  }

  info->root->colour = Element::Black;

  x = lastElement;
  lastIndex = x->left->subTreeSize;
  while (x != info->root) {
    if (x != x->parent->left)
      lastIndex += x->parent->left->subTreeSize+1;
    x = x->parent;
  }

  reference->size++;
  return lastIndex;
}


PBoolean PAbstractSortedList::Remove(const PObject * obj)
{
  PSortedListElement * lastElement;
  if (GetObjectsIndex(obj, lastElement) == P_MAX_INDEX)
    return PFalse;

  RemoveElement(lastElement);
  return PTrue;
}


PObject * PAbstractSortedList::RemoveAt(PINDEX index)
{
  Element * node = info->OrderSelect(info->root, index+1);
  if (node == &info->nil)
    return NULL;

  PObject * data = node->data;
  RemoveElement(node);
  return reference->deleteObjects ? (PObject *)NULL : data;
}


void PAbstractSortedList::RemoveAll()
{
  if (info->root != &info->nil) {
    DeleteSubTrees(info->root, reference->deleteObjects);
    delete info->root;
    info->root = &info->nil;
    reference->size = 0;
  }
}


PINDEX PAbstractSortedList::Insert(const PObject &, PObject * obj)
{
  return Append(obj);
}


PINDEX PAbstractSortedList::InsertAt(PINDEX, PObject * obj)
{
  return Append(obj);
}


PBoolean PAbstractSortedList::SetAt(PINDEX, PObject *)
{
  return PFalse;
}


PObject * PAbstractSortedList::GetAt(PINDEX index) const
{
  if (index >= GetSize())
    return NULL;

  PSortedListElement * lastElement = info->OrderSelect(info->root, index+1);
  return PAssertNULL(lastElement)->data;
}


PINDEX PAbstractSortedList::GetObjectsIndex(const PObject * obj) const
{
  PSortedListElement * lastElement;
  return PAbstractSortedList::GetObjectsIndex(obj, lastElement);
}

PINDEX PAbstractSortedList::GetObjectsIndex(const PObject * obj, PSortedListElement * & lastElement) const
{
  Element * elmt = NULL;
  PINDEX pos = ValueSelect(info->root, *obj, (const Element **)&elmt);
  if (pos == P_MAX_INDEX)
    return P_MAX_INDEX;

  if (elmt->data != obj) {
    PINDEX savePos = pos;
    Element * saveElmt = elmt;
    while (elmt->data != obj &&
            (elmt = info->Predecessor(elmt)) != &info->nil &&
            *obj == *elmt->data)
      pos--;
    if (elmt->data != obj) {
      pos = savePos;
      elmt = saveElmt;
      while (elmt->data != obj &&
              (elmt = info->Successor(elmt)) != &info->nil &&
              *obj == *elmt->data)
        pos++;
      if (elmt->data != obj)
        return P_MAX_INDEX;
    }
  }

  lastElement = elmt;

  return pos;
}


PINDEX PAbstractSortedList::GetValuesIndex(const PObject & obj) const
{
  PSortedListElement * lastElement;
  PINDEX lastIndex = ValueSelect(info->root, obj, (const Element **)&lastElement);
  if (lastIndex == P_MAX_INDEX)
    return P_MAX_INDEX;

  Element * prev;
  while ((prev = info->Predecessor(lastElement)) != &info->nil &&
                                  prev->data->Compare(obj) == EqualTo) {
    lastElement = prev;
    lastIndex--;
  }

  return lastIndex;
}


void PAbstractSortedList::RemoveElement(Element * node)
{
  // Don't try an remove one of the special leaf nodes!
  if (PAssertNULL(node) == &info->nil)
    return;

  if (node->data != NULL && reference->deleteObjects)
    delete node->data;

  Element * y = node->left == &info->nil || node->right == &info->nil ? node : info->Successor(node);

  Element * t = y;
  while (t != &info->nil) {
    t->subTreeSize--;
    t = t->parent;
  }

  Element * x = y->left != &info->nil ? y->left : y->right;
  x->parent = y->parent;

  if (y->parent == &info->nil)
    info->root = x;
  else if (y == y->parent->left)
    y->parent->left = x;
  else
    y->parent->right = x;

  if (y != node)
    node->data = y->data;

  if (y->colour == Element::Black) {
    while (x != info->root && x->colour == Element::Black) {
      if (x == x->parent->left) {
        Element * w = x->parent->right;
        if (w->colour == Element::Red) {
          w->colour = Element::Black;
          x->parent->colour = Element::Red;
          LeftRotate(x->parent);
          w = x->parent->right;
        }
        if (w->left->colour == Element::Black && w->right->colour == Element::Black) {
          w->colour = Element::Red;
          x = x->parent;
        }
        else {
          if (w->right->colour == Element::Black) {
            w->left->colour = Element::Black;
            w->colour = Element::Red;
            RightRotate(w);
            w = x->parent->right;
          }
          w->colour = x->parent->colour;
          x->parent->colour = Element::Black;
          w->right->colour = Element::Black;
          LeftRotate(x->parent);
          x = info->root;
        }
      }
      else {
        Element * w = x->parent->left;
        if (w->colour == Element::Red) {
          w->colour = Element::Black;
          x->parent->colour = Element::Red;
          RightRotate(x->parent);
          w = x->parent->left;
        }
        if (w->right->colour == Element::Black && w->left->colour == Element::Black) {
          w->colour = Element::Red;
          x = x->parent;
        }
        else {
          if (w->left->colour == Element::Black) {
            w->right->colour = Element::Black;
            w->colour = Element::Red;
            LeftRotate(w);
            w = x->parent->left;
          }
          w->colour = x->parent->colour;
          x->parent->colour = Element::Black;
          w->left->colour = Element::Black;
          RightRotate(x->parent);
          x = info->root;
        }
      }
    }
    x->colour = Element::Black;
  }

  delete y;

  reference->size--;
}


void PAbstractSortedList::LeftRotate(Element * node)
{
  Element * pivot = PAssertNULL(node)->right;
  node->right = pivot->left;
  if (pivot->left != &info->nil)
    pivot->left->parent = node;
  pivot->parent = node->parent;
  if (node->parent == &info->nil)
    info->root = pivot;
  else if (node == node->parent->left)
    node->parent->left = pivot;
  else
    node->parent->right = pivot;
  pivot->left = node;
  node->parent = pivot;
  pivot->subTreeSize = node->subTreeSize;
  node->subTreeSize = node->left->subTreeSize + node->right->subTreeSize + 1;
}


void PAbstractSortedList::RightRotate(Element * node)
{
  Element * pivot = PAssertNULL(node)->left;
  node->left = pivot->right;
  if (pivot->right != &info->nil)
    pivot->right->parent = node;
  pivot->parent = node->parent;
  if (node->parent == &info->nil)
    info->root = pivot;
  else if (node == node->parent->right)
    node->parent->right = pivot;
  else
    node->parent->left = pivot;
  pivot->right = node;
  node->parent = pivot;
  pivot->subTreeSize = node->subTreeSize;
  node->subTreeSize = node->left->subTreeSize + node->right->subTreeSize + 1;
}


PSortedListElement * PSortedListInfo::Successor(const PSortedListElement * node) const
{
  Element * next;
  if (node->right != &nil) {
    next = node->right;
    while (next->left != &nil)
      next = next->left;
  }
  else {
    next = node->parent;
    while (next != &nil && node == next->right) {
      node = next;
      next = node->parent;
    }
  }
  return next;
}


PSortedListElement * PSortedListInfo::Predecessor(const PSortedListElement * node) const
{
  Element * pred;
  if (node->left != &nil) {
    pred = node->left;
    while (pred->right != &nil)
      pred = pred->right;
  }
  else {
    pred = node->parent;
    while (pred != &nil && node == pred->left) {
      node = pred;
      pred = node->parent;
    }
  }
  return pred;
}


PSortedListElement * PSortedListInfo::OrderSelect(PSortedListElement * node, PINDEX index) const
{
  PINDEX r = node->left->subTreeSize+1;
  if (index == r)
    return node;

  if (index < r) {
    if (node->left != &nil)
      return OrderSelect(node->left, index);
  }
  else {
    if (node->right != &nil)
      return OrderSelect(node->right, index - r);
  }

  PAssertAlways2("PAbstractSortedList::Element", "Order select failed!");
  return (Element *)&nil;
}


PINDEX PAbstractSortedList::ValueSelect(const Element * node,
                                        const PObject & obj,
                                        const Element ** lastElement) const
{
  if (node != &info->nil) {
    switch (node->data->Compare(obj)) {
      case PObject::LessThan :
      {
        PINDEX index = ValueSelect(node->right, obj, lastElement);
        if (index != P_MAX_INDEX)
          return node->left->subTreeSize + index + 1;
        break;
      }

      case PObject::GreaterThan :
        return ValueSelect(node->left, obj, lastElement);

      default :
        *lastElement = node;