//this function is useful for search and modify, and range-query
ISNode* //return the first key's position that >= *_key
ISTree::find(int _key, int* _store, bool ifmodify)
{ //to assign value for this->bstr, function shouldn't be const!
if (this->root == NULL)
return NULL; //ISTree Is Empty
ISNode* p = root;
int i, j;
while (!p->isLeaf())
{
if (ifmodify)
p->setDirty();
//j = p->getNum();
//for(i = 0; i < j; ++i) //BETTER(Binary-Search)
//if(bstr < *(p->getKey(i)))
//break;
i = p->searchKey_less(_key);
p = p->getChild(i);
this->prepare(p);
}
j = p->getNum();
//for(i = 0; i < j; ++i)
//if(bstr <= *(p->getKey(i)))
//break;
i = p->searchKey_lessEqual(_key);
if (i == j)
*_store = -1; //Not Found
else
*_store = i;
return p;
}
bool //special case: not exist, one-edge-case
ISTree::range_query(int _key1, int _key2)
{ //the range is: *_key1 <= x < *_key2
//if(_key1 <0 && _key2 <0)
//return false;
//ok to search one-edge, requiring only one be negative
//find and write value
int store1, store2;
ISNode *p1, *p2;
if (_key1 >= 0)
{
request = 0;
p1 = this->find(_key1, &store1, false);
if (p1 == NULL || store1 == -1)
return false; //no element
this->TSM->request(request);
}
else
{
p1 = this->leaves_head;
store1 = 0;
}
if (_key2 >= 0)
{ //QUERY: another strategy is to getnext and compare every time to tell end
request = 0;
p2 = this->find(_key2, &store2, false);
if (p2 == NULL)
return false;
else if (store2 == -1)
store2 = p2->getNum();
else if (store2 == 0)
{
p2 = p2->getPrev();
if (p2 == NULL)
return false; //no element
store2 = p2->getNum();
}
this->TSM->request(request);
}
else
{
p2 = this->leaves_tail;
store2 = p2->getNum();
}
ISNode* p = p1;
unsigned i, l, r;
//get the num of answers first, not need to prepare the node
unsigned ansNum = 0;
while (true)
{
//request = 0;
//this->prepare(p);
if (p == p1)
l = store1;
else
l = 0;
if (p == p2)
r = store2;
else
r = p->getNum();
ansNum += (r - l);
//this->TSM->request(request);
if (p != p2)
p = p->getNext();
else
break;
}
if (this->stream != NULL)
{
delete this->stream;
this->stream = NULL;
}
vector<int> keys;
vector<bool> desc;
this->stream = new Stream(keys, desc, ansNum, 1, false);
p = p1;
while (1)
{
request = 0;
this->prepare(p);
if (p == p1)
l = store1;
else
l = 0;
if (p == p2)
r = store2;
else
r = p->getNum();
for (i = l; i < r; ++i)
{
//NOTICE:Bstr* in an array, used as Bstr[]
this->stream->write(p->getValue(i));
}
this->TSM->request(request);
if (p != p2)
p = p->getNext();
else
break;
}
this->stream->setEnd();
return true;
}
bool
ISTree::remove(int _key)
{
if (_key < 0)
{
printf("error in ISTree-remove: empty string\n");
return false;
}
this->request = 0;
ISNode* ret;
if (this->root == NULL) //tree is empty
return false;
ISNode* p = this->root;
ISNode* q;
int i, j;
while (!p->isLeaf())
{
j = p->getNum();
//for(i = 0; i < j; ++i)
//if(bstr < *(p->getKey(i)))
//break;
i = p->searchKey_less(_key);
q = p->getChild(i);
this->prepare(q);
if (q->getNum() < ISNode::MIN_CHILD_NUM) //==MIN_KEY_NUM
{
if (i > 0)
this->prepare(p->getChild(i - 1));
if (i < j)
this->prepare(p->getChild(i + 1));
ret = q->coalesce(p, i);
if (ret != NULL)
this->TSM->updateHeap(ret, 0, true);//non-sense node
this->TSM->updateHeap(q, q->getRank(), true);
if (q->isLeaf())
{
if (q->getPrev() == NULL)
this->leaves_head = q;
if (q->getNext() == NULL)
this->leaves_tail = q;
}
if (p->getNum() == 0) //root shrinks
{
//this->leaves_head = q;
this->root = q;
this->TSM->updateHeap(p, 0, true); //instead of delete p
this->height--;
}
}
else
p->setDirty();
this->TSM->updateHeap(p, p->getRank(), true);
p = q;
}
bool flag = false;
//j = p->getNum(); //LeafNode(maybe root)
//for(i = 0; i < j; ++i)
// if(bstr == *(p->getKey(i)))
// {
// request -= p->getKey(i)->getLen();
// request -= p->getValue(i)->getLen();
// p->subKey(i, true); //to release
// p->subValue(i, true); //to release
// p->subNum();
// if(p->getNum() == 0) //root leaf 0 key
// {
// this->root = NULL;
// this->leaves_head = NULL;
// this->leaves_tail = NULL;
// this->height = 0;
// this->TSM->updateHeap(p, 0, true); //instead of delete p
// }
// p->setDirty();
// flag = true;
// break;
// }
i = p->searchKey_equal(_key);
//WARN+NOTICE:here must check, because the key to remove maybe not exist
if (i != (int)p->getNum())
{
request -= p->getValue(i)->getLen();
p->subKey(i); //to release
p->subValue(i, true); //to release
p->subNum();
if (p->getNum() == 0) //root leaf 0 key
{
this->root = NULL;
this->leaves_head = NULL;
this->leaves_tail = NULL;
this->height = 0;
this->TSM->updateHeap(p, 0, true); //instead of delete p
}
p->setDirty();
flag = true;
}
this->TSM->request(request);
return flag; //i == j, not found
}
bool
ISTree::insert(int _key, const char* _str, unsigned _len)
{
if (_key < 0)
{
printf("error in ISTree-insert: empty string\n");
return false;
}
this->CopyToTransfer(_str, _len, 2);
const Bstr* val = &(this->transfer[2]);
this->request = 0;
ISNode* ret;
if (this->root == NULL) //tree is empty
{
leaves_tail = leaves_head = root = new ISLeafNode;
request += ISNode::LEAF_SIZE;
this->height = 1;
root->setHeight(1); //add to heap later
}
//this->prepare(this->root); //root must be in-mem
if (root->getNum() == ISNode::MAX_KEY_NUM)
{
ISNode* father = new ISIntlNode;
request += ISNode::INTL_SIZE;
father->addChild(root, 0);
ret = root->split(father, 0);
if (ret->isLeaf() && ret->getNext() == NULL)
this->leaves_tail = ret;
if (ret->isLeaf())
request += ISNode::LEAF_SIZE;
else
request += ISNode::INTL_SIZE;
this->height++; //height rises only when root splits
//WARN: height area in Node: 4 bit!
father->setHeight(this->height); //add to heap later
this->TSM->updateHeap(ret, ret->getRank(), false);
this->root = father;
}
ISNode* p = this->root;
ISNode* q;
int i;
while (!p->isLeaf())
{
//j = p->getNum();
//for(i = 0; i < j; ++i)
//if(bstr < *(p->getKey(i)))
//break;
//NOTICE: using binary search is better here
i = p->searchKey_less(_key);
q = p->getChild(i);
this->prepare(q);
if (q->getNum() == ISNode::MAX_KEY_NUM)
{
ret = q->split(p, i);
if (ret->isLeaf() && ret->getNext() == NULL)
this->leaves_tail = ret;
if (ret->isLeaf())
request += ISNode::LEAF_SIZE;
else
request += ISNode::INTL_SIZE;
//BETTER: in loop may update multiple times
this->TSM->updateHeap(ret, ret->getRank(), false);
this->TSM->updateHeap(q, q->getRank(), true);
this->TSM->updateHeap(p, p->getRank(), true);
if (_key < p->getKey(i))
p = q;
else
p = ret;
}
else
{
p->setDirty();
this->TSM->updateHeap(p, p->getRank(), true);
p = q;
}
}
//j = p->getNum();
//for(i = 0; i < j; ++i)
//if(bstr < *(p->getKey(i)))
//break;
i = p->searchKey_less(_key);
//insert existing key is ok, but not inserted in
//however, the tree-shape may change due to possible split in former code
bool ifexist = false;
if (i > 0 && _key == p->getKey(i - 1))
ifexist = true;
else
{
p->addKey(_key, i);
p->addValue(val, i, true);
p->addNum();
request += val->getLen();
p->setDirty();
this->TSM->updateHeap(p, p->getRank(), true);
//_key->clear();
//_value->clear();
}
this->TSM->request(request);
return !ifexist; //QUERY(which case:return false)
}