Index::Index(std::string name, std::string type, int keyLen){
this->debug = false;
this->d = false;
this->name = name;
this->type = type;
this->keyLen = keyLen;
this->maxKeyNum = (Block::BLOCK_SIZE - 12) / (keyLen + 4) - 3;
this->fileName = "index-" + name + ".wk";
BufferManager* bm = BufferManager::getInstance();
if (bm->isFileExists(fileName)){
bm->read(fileName, 0, &(this->last));//last block
int m, x;
bm->read(fileName, &m); //root
if (m != -1) {
this->root = new Node(this, m);
} else
this->root = NULL;
bm->read(fileName, 8, &m);
for (int i=0; i<m; i++){
bm->read(fileName, &x);
(this->holes).push_back(x);
}
} else {
this->last = 0;
this->root = NULL;
bm->write(fileName, 0, this->last);
bm->write(fileName, -1);
bm->write(fileName, (int)holes.size());
}
}
Index::~Index(){
BufferManager* bm = BufferManager::getInstance();
bm->write(fileName, 0, this->last);
if (root != NULL)
bm->write(fileName, this->root->getAddr());
else
bm->write(fileName, -1);
bm->write(fileName, (int)holes.size());
std::list<int>::iterator itr;
for (itr=holes.begin(); itr!=holes.end(); itr++){
bm->write(fileName, *itr);
}
std::map<int, Node*>::iterator nodeItr;
for (nodeItr=nodes.begin(); nodeItr!=nodes.end(); nodeItr++){
delete nodeItr->second;
}
}
Node* Index::newNode(){
int n;
Node* ret;
if (holes.empty()){
last += Block::BLOCK_SIZE;
n = last;
} else {
n = holes.front();
holes.pop_front();
}
BufferManager* bm = BufferManager::getInstance();
unsigned char* buf = new unsigned char[Block::BLOCK_SIZE];
bm->write(this->getFileName(), n, Block::BLOCK_SIZE, buf); // write block
bm->write(this->getFileName(), n, -1); // set parent to -1
bm->write(this->getFileName(), 0);// set keynum
bm->write(this->getFileName(), 0);// set noninternal
delete[] buf;
ret = new Node(this, n);
nodes.insert(std::map<int, Node*>::value_type(n, ret));
return ret;
}
