C++ GiSTnode类代码示例

// adjust the keys of node, which is used during the final phase of the BulkLoad algorithm
void
MT::AdjKeys (GiSTnode *node)
{
	if (node->Path().IsRoot()) {
		return;
	}

	GiSTpath parentPath = node->Path();
	parentPath.MakeParent ();
	GiSTnode *parentNode = ReadNode (parentPath);
	GiSTentry *parentEntry = parentNode->SearchPtr(node->Path().Page());  // parent entry
	assert (parentEntry != NULL);
	GiSTentry *unionEntry = node->Union();
	unionEntry->SetPtr(node->Path().Page());
	((MTkey *) unionEntry->Key())->distance = ((MTkey *) parentEntry->Key())->distance;  // necessary to keep track of the distance from the parent
	if (!parentEntry->IsEqual(*unionEntry)) {  // replace this entry
		parentNode->DeleteEntry(parentEntry->Position());
		parentNode->Insert(*unionEntry);
		WriteNode (parentNode);
		AdjKeys (parentNode);
	}
	delete unionEntry;
	delete parentEntry;
	delete parentNode;
}

void 
GiST::Delete (const GiSTpredicate& pred)
{
	GiSTcursor *c = Search (pred);
	GiSTentry *e;

	do {
		if (c == NULL) {
			return;
		}
		e = c->Next();
		GiSTpath path = c->Path();
		delete c;
		if (e == NULL) {
			return;
		}
		// Read in the node that this belongs to
		GiSTnode *node = ReadNode (path);
		node->DeleteEntry(e->Position());
		WriteNode (node);

		int condensed = CondenseTree (node);
		delete node;
		if (condensed) {
			ShortenTree ();
			// because the tree changed, we need to search all over again!
			// XXX - this is inefficient!  users may want to avoid condensing.
			c = Search (pred);
		}
	} while (e != NULL);
}

GiSTnode* 
GiST::ChooseSubtree(GiSTpage page, const GiSTentry &entry, int level)
{
	GiSTnode *node;
	GiSTpath path;

	for(;;) {
		path.MakeChild(page);
		node=ReadNode(path);
		if(level==node->Level()||node->IsLeaf()) break;
		page=node->SearchMinPenalty(entry);
		delete node;
	}
	return node;
}

GiSTnode* 
GiST::ReadNode (const GiSTpath& path) const
{
	char *buf = new char[store->PageSize()];
	GiSTnode *node = NewNode((GiST *)this);

	store->Read(path.Page(), buf);  // do the deed
	node->Unpack(buf);

#ifdef PRINTING_OBJECTS
	if (debug) {
		cout << "READ PAGE " << path.Page() << ":\n";
		node->Print(cout);
	}
#endif
	node->Path() = path;
	delete []buf;
	return node;
}

void
MT::CollectStats ()
{
	GiSTpath path;
	path.MakeRoot ();
	GiSTnode *node = ReadNode (path);
	if (!node->IsLeaf()) {
		int maxLevel = node->Level();
		double *radii = new double[maxLevel];
		int *pages = new int[maxLevel];
		for (int i=0; i<maxLevel; i++) {
			pages[i] = 0;
			radii[i] = 0;
		}
		TruePredicate truePredicate;
		GiSTlist<GiSTentry*> list = node->Search(truePredicate);  // retrieve all the entries in this node
		
		double overlap = ((MTnode *)node)->Overlap();
		double totalOverlap = overlap;
		
		delete node;
		while (!list.IsEmpty()) {
			GiSTentry *entry = list.RemoveFront ();
			path.MakeChild (entry->Ptr());
			node = ReadNode (path);

			overlap = ((MTnode *)node)->Overlap();
			totalOverlap += overlap;

			pages[node->Level()]++;
			radii[node->Level()] += ((MTkey *) entry->Key())->MaxRadius();
			GiSTlist<GiSTentry*> newlist;
			if (!node->IsLeaf()) {
				newlist = node->Search(truePredicate);  // recurse to next level
			}
			while (!newlist.IsEmpty()) {
				list.Append (newlist.RemoveFront ());
			}
			path.MakeParent ();
			delete entry;
			delete node;
		}
		// output the results
		cout << "Level:\tPages:\tAverage_Radius:"<<endl;
		int totalPages = 1;  // for the root
		for (int i=maxLevel-1; i>=0; i--) {
			totalPages += pages[i];
			cout << i << ":\t" << pages[i] << "\t" << radii[i]/pages[i] << endl;
		}
		cout << "TotalPages:\t" << totalPages << endl;
		cout << "LeafPages:\t" << pages[0] << endl;
		cout << "TotalOverlap:\t" << (float)totalOverlap << endl;
		delete []radii;
		delete []pages;
	} else {
		delete node;
	}
}

void 
GiST::Create (const char *filename)
{
	if (IsOpen()) {
		return;
	}
	store = CreateStore();
	store->Create(filename);
	if (!store->IsOpen()) {  // create failed!
		return;
	}
	store->Allocate();  // added by myself, reserved for root
	store->Allocate();
	GiSTnode *node = NewNode(this);
	node->Path().MakeRoot();
	WriteNode (node);
	delete node;
	isOpen = 1;
}

void MXTree::Create(const char *filename)
{
	if (IsOpen()) {
		return;
	}
	store = CreateStore();
	store->Create(filename);
	if (!store->IsOpen()) { 
		return;
	}
	store->Allocate();  // reserved for root pointer
	rootPage = store->Allocate();
	assert(rootPage == 1);
	GiSTnode *node = NewNode(this);
	node->Path().MakeRoot();
	WriteNode(node);
	delete node;
	isOpen = 1;
}

GiSTentry* 
GiSTcursor::Next()
{
    GiSTpage page;

    while (first || !stack.IsEmpty()) {
	if (first) {
	    page = GiSTRootPage;
	    first = 0;
	} else {
	    assert(lastlevel >= 0);
	    GiSTentry *entry = stack.RemoveFront();
	    if (entry->IsLeaf())
		return entry;

	    // Pop off the stack
	    for (int i=0; i < entry->Level() - lastlevel; i++)
		path.MakeParent();

	    page = entry->Ptr();
	    
	    delete entry;
	}

	// Entry was a pointer to another node
	path.MakeChild(page);

	GiSTnode *node = gist.ReadNode(path);
	lastlevel = node->Level();

	GiSTlist<GiSTentry*> list = node->Search(*query);

	while (!list.IsEmpty()) {
	    GiSTentry *entry = list.RemoveRear();
	    stack.Prepend(entry);
	}

	delete node;
    }

    // The search is over...
    return NULL;
}

void 
GiST::DumpNode (ostream& os, GiSTpath path) const
{
	GiSTnode *node = ReadNode(path);
	node->Print(os);

	if (!node->IsLeaf()) {
		TruePredicate truePredicate;
		GiSTlist<GiSTentry*> list = node->Search(truePredicate);

		while (!list.IsEmpty()) {
			GiSTentry *e = list.RemoveFront();
			path.MakeChild(e->Ptr());
			DumpNode (os, path);
			path.MakeParent();
			delete e;
		}
	}
	delete node;
}

void 
GiST::InsertHelper(const GiSTentry &entry, 
		   int level, // level of tree at which to insert
		   int *splitvec) // a vector to trigger Split instead of forced reinsert
{
	GiSTnode *leaf;
	int overflow=0;

	leaf=ChooseSubtree(GiSTRootPage, entry, level);
	leaf->Insert(entry);
	if (leaf->IsOverFull(*store)) {
		if(ForcedReinsert()&&!leaf->Path().IsRoot()&&(!splitvec||!splitvec[level])) {
			int split[GIST_MAX_LEVELS];

			// R*-tree-style forced reinsert
			for(int i=0; i<GIST_MAX_LEVELS; i++) split[i]=0;
			OverflowTreatment(leaf, entry, split);
			overflow=1;
		}
		else Split(&leaf, entry);
		if(leaf->IsOverFull(*store)) {
			// we only should get here if we reinserted, and the node re-filled
			assert(overflow);
			leaf->DeleteEntry(entry.Position());
			Split(&leaf, entry);
		}
	}
	else WriteNode(leaf);
	if(!overflow) AdjustKeys(leaf, NULL);
	delete leaf;
}

double
RTentry::OverlapArea(const RTkey &k) const
{
  int i;
  GiSTnode *n = Node();
  RTkey *okey, *tmpkey;
  double retval;

  okey = new RTkey(k);

  for (i = 0; i < n->NumEntries(); i++)
    if (i != Position()) {
      tmpkey = okey;
      okey = tmpkey->intersect(((RTentry *)((*n)[i].Ptr()))->bbox());
      delete tmpkey;
      if (okey == NULL)
	return(0);
    }
  retval = okey->area();
  delete okey;
  return(retval);
}

GiSTnode* MXTree::ReadNode(const GiSTpath& path) const
{
	char *firstBuffer = new char[store->PageSize()];
	int startPage = (path.IsRoot() ? rootPage : path.Page());
	store->Read(startPage, firstBuffer);
	int pageNum = ceil((float)(((MXTnodeHeader *)firstBuffer)->numEntries*(EntrySize()+sizeof(GiSTpage))+sizeof(MXTnodeHeader))/(float)PAGE_SIZE);
	GiSTnode *node = new MXTnode(pageNum);
	node->SetTree((GiST *)this);
	node->Path() = path;
	if (pageNum > 1) {
		char *buffer = new char[store->PageSize()*pageNum];
		memset(buffer, 0, store->PageSize()*pageNum);
		memcpy(buffer, firstBuffer, store->PageSize());
		((MXTfile *)store)->Read(startPage+1, buffer+store->PageSize(), pageNum-1);  // do the deed
		node->Unpack(buffer);
		delete[] buffer;
	} else {
		node->Unpack(firstBuffer);
	}
	delete[] firstBuffer;

	return node;
}

//.........这里部分代码省略.........
		GiSTpath path;
		path.MakeRoot ();
		MTnode *node = (MTnode *) ReadNode (path);
		GiSTlist<MTnode *> *oldList = new GiSTlist<MTnode *>;  // upper level nodes
		oldList->Append(node);
		int level = node->Level();
		while (level > 0) {  // build the leaves list for super tree
			GiSTlist<MTnode *> *newList = new GiSTlist<MTnode *>;  // lower level nodes
			while (!oldList->IsEmpty()) {
				node = oldList->RemoveFront();
				path = node->Path();
				node->SetLevel(node->Level() + minHeight);  // update level of the upper nodes of the super tree
				WriteNode (node);
				for (int i=0; i<node->NumEntries(); i++) {
					MTentry *entry = (MTentry *) (*node)[i].Ptr();
					path.MakeChild (entry->Ptr());
					newList->Append((MTnode *)ReadNode(path));
					path.MakeParent ();
				}
				delete node;
			}
			delete oldList;
			oldList = newList;
			level--;
		}
		while (!oldList->IsEmpty()) {  // attach each subtree to its leaf
			node = oldList->RemoveFront();  // retrieve next leaf (root of subtree)
			node->SetLevel(minHeight);  // update level of the root of the subtree
			path = node->Path();
			for (int i=0; i<node->NumEntries(); i++) {
				MTentry *entry = (MTentry *) (*node)[i].Ptr();
				path.MakeChild(Store()->Allocate());
				MTnode *newNode = (MTnode *) CreateNode ();
				newNode->Path() = path;
				entry->SetPtr(path.Page());
				path.MakeParent ();
				int j = 0;
				for (; entry->object() != topEntrArr[j]->object(); j++);  // search the position to append
				subtree->Open(subNameArr[j]);
				GiSTpath rootPath;
				rootPath.MakeRoot ();
				Append (newNode, (MTnode *)subtree->ReadNode(rootPath));  // append this subtree to the super tree
				subtree->Close();
				delete subtree->Store();  // it was created in tree->Open()
				delete newNode;
			}
			WriteNode (node);
			delete node;
		}
		subtree->Open(subNameArr[0]);  // in order to destroy the object tree
		delete subtree;
		for (int i=0; i<nSamples; i++) {
			delete []subNameArr[i];
		}
		delete []subNameArr;
		delete []topEntrArr;

		// update radii of the upper nodes of the result M-tree
		path.MakeRoot ();
		node = (MTnode *) ReadNode (path);
		oldList->Append(node);
		level = node->Level();
		while (level >= minHeight) {  // build the list of the nodes which radii should be recomputed
			GiSTlist<MTnode *> *newList = new GiSTlist<MTnode *>;
			while (!oldList->IsEmpty()) {
				node = oldList->RemoveFront();
				path = node->Path();
				for (int i=0; i<node->NumEntries(); i++) {
					path.MakeChild ((*node)[i].Ptr()->Ptr());
					newList->Append((MTnode *)ReadNode(path));
					path.MakeParent ();
				}
				delete node;
			}
			delete oldList;
			oldList = newList;
			level--;
		}
		while (!oldList->IsEmpty()) {  // adjust the radii of the nodes
			MTnode *node = oldList->RemoveFront();
			AdjKeys (node);
			delete node;
		}
		delete oldList;
		for (int i=0; i<=nCreated; i++) {  // delete all temporary subtrees
			sprintf (newName, "%s.%i", name, i);
			unlink (newName);
		}
	} else {  // we can insert all the entries in a single node
		GiSTpath path;
		path.MakeRoot ();
		GiSTnode *node = ReadNode (path);
		for (int i=0; i<n; i++) {
			node->Insert(*(data[i]));
		}
		assert (!node->IsOverFull(*Store()));
		WriteNode (node);
		delete node;
	}
}

// handle underfull leaf nodes
int
GiST::CondenseTree(GiSTnode *node)
{
	GiSTlist<GiSTentry*> Q;
	int deleted=0;

	// Must be condensing a leaf
	assert(node->IsLeaf());
	while(!node->Path().IsRoot()) {
		GiSTpath parent_path=node->Path();
		parent_path.MakeParent();
		GiSTnode *P=ReadNode(parent_path);
		GiSTentry *En=P->SearchPtr(node->Path().Page());

		assert(En!=NULL);
		// Handle under-full node
		if(node->IsUnderFull(*store)) {
		    if(!IsOrdered()) {
				TruePredicate truePredicate;
				GiSTlist<GiSTentry*> list=node->Search(truePredicate);

				while(!list.IsEmpty()) {
					GiSTentry *e=list.RemoveFront();

					Q.Append(e);
				}
				P->DeleteEntry(En->Position());
				WriteNode(P);
				deleted=1;
				AdjustKeys(P, NULL);
			}
			else {
				// Try to borrow entries, else coalesce with a neighbor
				// Have to look at left sibling???
				GiSTpage neighbor_page=P->SearchNeighbors(node->Path().Page());
				GiSTpath neighbor_path=node->Path();

				neighbor_path.MakeSibling(neighbor_page);
				if(neighbor_page!=0) {
					GiSTnode *neighbor;

					// If neighbor is RIGHT sibling...
					if(node->Sibling()==neighbor_page) neighbor=ReadNode(neighbor_path);
                    else {
						neighbor=node;
						node=ReadNode(neighbor_path);
					}

					GiSTentry *e=P->SearchPtr(node->Path().Page());

					node->Coalesce(*neighbor, *e);
					delete e;
					// If not overfull, coalesce, kill right node
					if(!node->IsOverFull(*store)) {
						node->SetSibling(neighbor->Sibling());
						WriteNode(node);

						// Delete the neighbor from parent
						GiSTentry *e=P->SearchPtr(neighbor->Path().Page());

						P->DeleteEntry(e->Position());
						WriteNode(P);
						delete e;
						store->Deallocate(neighbor->Path().Page());
						deleted=1;
					}
					// If overfull, split (same as borrowing)
					else {
						GiSTnode *node2=node->PickSplit();

						node2->Path()=neighbor->Path();
						node2->SetSibling(neighbor->Sibling());
						WriteNode(node);
						WriteNode(node2);
						AdjustKeys(node2, &P);
						delete node2;
						deleted=1;
					}
					delete neighbor;
				}
			}
		}
		// Adjust covering predicate
		if(!deleted) AdjustKeys(node, &P);
		parent_path=node->Path();
		parent_path.MakeParent();
		delete node;
		// Propagate deletes
		if(!deleted) break;
		node=P;
	}
	// Re-insert orphaned entries
	while(!Q.IsEmpty()) {
		GiSTentry *e=Q.RemoveFront();

		InsertHelper(*e, e->Level());
		delete e;
	}
	return(deleted);
//.........这里部分代码省略.........

void MXTree::Split(GiSTnode **node, const GiSTentry& entry)
{
	double radii[2], dist, *dists = new double[(*node)->NumEntries()*2];
	int pageNums[2], cands[2];
	vector<vector<int>> vec(2);
	((MXTnode *)(*node))->TestPromotion(radii, &dist, pageNums, cands, dists, vec);
	if (Trade((*node)->Path().IsRoot(), radii, dist, pageNums, ((MXTnode *)(*node))->GetPageNum()+1, (*node)->NumEntries())) {
		// don't split now
		delete[] dists;
		GiSTpath oldPath = (*node)->Path();

		int startPage = ((*node)->Path().IsRoot() ? rootPage : (*node)->Path().Page());
		int pageNum = ((MXTnode *)(*node))->GetPageNum();
		((MXTfile *)store)->Deallocate(startPage, pageNum);
		startPage = ((MXTfile *)store)->Allocate(++pageNum);
		(*node)->Path().MakeSibling(startPage);
		rootPage = ((*node)->Path().IsRoot() ? startPage : rootPage);
		((MXTnode *)(*node))->SetPageNum(pageNum);
		WriteNode(*node);

		if (!(*node)->Path().IsRoot() && startPage != oldPath.Page()) {
			GiSTpath parentPath = oldPath;
			parentPath.MakeParent();
			GiSTnode *parentNode = ReadNode(parentPath);
			GiSTentry *e = parentNode->SearchPtr(oldPath.Page());
			assert(e != NULL);
			int pos = e->Position();
			e->SetPtr(startPage);
			parentNode->DeleteEntry(pos);
			parentNode->InsertBefore(*e, pos);
			WriteNode(parentNode);
			delete parentNode;
			delete e;
		}
	} else {
		// split now
		bool bLeft = false, bNewRoot = false;

		if ((*node)->Path().IsRoot()) {
			bNewRoot = true;
			(*node)->Path().MakeChild(rootPage);
			rootPage = store->Allocate();
		}

		int oldPageNum = ((MXTnode *)(*node))->GetPageNum();
		GiSTnode *node2 = ((MXTnode *)(*node))->PickSplit(cands, dists, vec);
		delete[] dists;
		int curPageNum = ((MXTnode *)(*node))->GetPageNum();
		assert(oldPageNum >= curPageNum);
		if (oldPageNum > curPageNum) {
			((MXTfile *)store)->Deallocate((*node)->Path().Page()+curPageNum, oldPageNum-curPageNum);
		}
		node2->Path().MakeSibling(((MXTfile *)store)->Allocate(((MXTnode *)node2)->GetPageNum()));

		WriteNode(*node);
		WriteNode(node2);
	
		GiSTentry *e = (*node)->SearchPtr(entry.Ptr());
		if (e != NULL) {
			bLeft = true;
			delete e;
		}
	
		GiSTentry *e1 = (*node)->Union();
		GiSTentry *e2 = node2->Union();
	
		e1->SetPtr((*node)->Path().Page());
		e2->SetPtr(node2->Path().Page());
		// Create new root if root is being split
		if (bNewRoot) {
			GiSTnode *root = NewNode(this);
			root->SetLevel((*node)->Level() + 1);
			root->InsertBefore(*e1, 0);
			root->InsertBefore(*e2, 1);
			root->Path().MakeRoot();
			WriteNode(root);
			delete root;
		} else {
			// Insert entry for N' in parent
			GiSTpath parentPath = (*node)->Path();
			parentPath.MakeParent();
			GiSTnode *parent = ReadNode(parentPath);
			// Find the entry for N in parent
			GiSTentry *e = parent->SearchPtr((*node)->Path().Page());
			assert(e != NULL);
			// Insert the new entry right after it
			int pos = e->Position();
			parent->DeleteEntry(pos);
			parent->InsertBefore(*e1, pos);
			parent->InsertBefore(*e2, pos+1);
			delete e;
			if (!parent->IsOverFull(*store)) {
				WriteNode(parent);
			} else {
				Split(&parent, bLeft? *e1: *e2);  // parent is the node which contains the entry inserted
				GiSTpage page = (*node)->Path().Page();
				(*node)->Path() = parent->Path();  // parent's path may change
				(*node)->Path().MakeChild(page);
				page = node2->Path().Page();
				node2->Path() = (*node)->Path();
//.........这里部分代码省略.........