/**
* First, an emptry file is allocated in the specified file.
* Then allocBuf() is called to obtain a buffer pool frame.
* Next, an entry is inserted into the hash table and Set() is invoked on the frame to set it up properly.
*
* @param file the pointer to the file
* @param PageNo the index of the page
* @param page the pointer to the frame which containing the page
* @return status the status of the function call
**/
const Status BufMgr::allocPage(File* file, int& pageNo, Page*& page)
{
Status status;
int frameNo;
// return the page number of the newly allocated page to the caller via the pageNo
status = file->allocatePage(pageNo);
if(status != OK)
return status;
status = allocBuf(frameNo);
if (status != OK)
return status;
status = hashTable->insert(file, pageNo, frameNo);
if (status != OK)
return status;
bufTable[frameNo].Set(file, pageNo);
bufTable[frameNo].frameNo = frameNo;
// return a pointer to the buffer frame allocated for the page via the page parameter
page = &(bufPool[frameNo]);
return OK;
}
const Status BufMgr::allocPage(File* file, int& pageNo, Page*& page)
{
// Your solution goes here
bufStats.accesses ++;
unsigned int frameno;
if(allocBuf(frameno) == BUFFEREXCEEDED){
return BUFFEREXCEEDED;
}
//cout << frameno << " " << bufTable[frameno].pinCnt << " " << bufTable[frameno].pageNo << endl;
Status isgood = file->allocatePage(pageNo);
if(isgood == UNIXERR){
//cout << "THERE!" << endl;
return UNIXERR;
}else if(isgood == OK){
bufStats.diskwrites ++;
}
bufTable[frameno].Set(file, pageNo);
//cout << "WHERE!" << endl;
if(bufMap.insert(file, pageNo, frameno) == BUFMAPERROR){
return BUFMAPERROR;
}
page = &bufPool[frameno];//Do I need to dereference this or something else?
//cout << " PAGE " << page << endl;
return OK;
}
/**
* Reads a page from either the buffer pool or disk.
* First check whether the page is already in the bufPool by invoking lookup() method.
* If it is not in the buffer pool, then read the page from disk into the buffer pool frame.
*
* @param file the pointer to the file
* @param PageNo the index of the page
* @param page the pointer to the frame which containing the page
* @return status the status of the function call
**/
const Status BufMgr::readPage(File* file, const int PageNo, Page*& page)
{
Status status;
int frameNo;
if (hashTable->lookup(file,PageNo,frameNo) != HASHNOTFOUND) {
// if page is in the bufPool
bufTable[frameNo].refbit = true;
bufTable[frameNo].pinCnt++;
} else {
status = allocBuf(frameNo);
if(status != OK)
return status;
// read the page from disk into the buffer pool frame
status = file->readPage(PageNo,&bufPool[frameNo]);
if(status != OK)
return status;
// insert the page into the hashTable
status = hashTable->insert(file,PageNo,frameNo);
if(status != OK)
return status;
bufTable[frameNo].Set(file,PageNo);
bufTable[frameNo].frameNo = frameNo;
}
// return a pointer to the frame containing the page via the page parameter
page = &bufPool[frameNo];
return OK;
}
/**
* This function allocate an empty page in the specified file by invoking the file->allocatePage() method.
* This method will return the page number of the newly allocated page.
* Then allocBuf() is called to obtain a buffer pool frame.
* Next, an entry is inserted into the hash table and Set() is invoked on the frame to set it up.
* @param file-a pointer to the file handle
* @param pageNo-the number of the page to be read
* @param page-a pointer to the page inside the frame
* @return Status-status information from function
**/
const Status BufMgr::allocPage(File* file, int& pageNo, Page*& page) {
Status rc;
int frameNo;
//I/O call to allocate a page
rc = file->allocatePage(pageNo);
if (rc != OK) {
return rc;
}
// allocate a buffer frame for the new page
rc = allocBuf(frameNo);
if (rc != OK) {
return rc;
}
//map new buffer addition in the hashTable
rc = hashTable->insert(file, pageNo, frameNo);
if (rc != OK) {
return rc;
}
//set page from disc in buffer frame
bufTable[frameNo].Set(file, pageNo);
bufTable[frameNo].frameNo = frameNo;
page = &bufPool[frameNo]; //pointer to the page to be read
return OK;
}// end function allocPage
/*
* Decrements the pinCnt of the frame containing (file, PageNo)
*
* Throws HashNotFoundException when page is not in the buffer pool,
* on the hashtable to get a frame number.
* params: File* file, const PageId pageNo, Page*& page
*/
void BufMgr::readPage(File* file, const PageId pageNo, Page*& page)
{
FrameId frame = -1;
// look up hashtable
try{
hashTable->lookup(file, pageNo, frame);
// page is within the hashtable
BufDesc* bufDesc = &(bufDescTable[frame]);
bufDesc->refbit = true;
bufDesc->pinCnt = bufDesc->pinCnt + 1;
page = &(bufPool[frame]);
}
// Page is not in the buffer pool
catch(HashNotFoundException) {
// calling this first to see if the page is valid
file->readPage(pageNo);
// Allocate frame
FrameId frame = -1;
allocBuf(frame);
page = &(bufPool[frame]);
*page = file->readPage(pageNo);
// insert into hash table
hashTable->insert(file, pageNo, frame);
// call Set()
BufDesc* bufDesc = &(bufDescTable[frame]);
bufDesc->Set(file, pageNo);
}
}
const Status BufMgr::readPage(File* file, const int PageNo, Page*& page)
{
Status status = OK;
int frameNo = 0;
status = hashTable->lookup(file, PageNo, frameNo);
if (status == OK) // Page is in the buffer pool
{
BufDesc * tmpbuf = &(bufTable[frameNo]);
tmpbuf->pinCnt++;
}
else // Page is not in the buffer pool
{
status = allocBuf(frameNo);
if (status != OK)
{
return status;
}
page = &(bufPool[frameNo]);
status = file->readPage(PageNo, page);
if (status != OK)
{
return status;
}
bufTable[frameNo].Set(file, PageNo);
status = hashTable->insert(file, PageNo, frameNo);
}
page = &(bufPool[frameNo]);
return status;
}
EncodeOutputCharStream::EncodeOutputCharStream(OutputByteStream *byteStream,
Encoder *encoder)
: buf_(0),
byteStream_(byteStream),
escaper_(0),
encoder_(encoder)
{
allocBuf(0);
}
void UnicodeEncoder::output(const Char *s, size_t n, streambuf *sb)
{
if (sizeof(Char) == 2) {
sb->sputn((char *)s, n*2);
return;
}
allocBuf(n);
for (size_t i = 0; i < n; i++)
buf_[i] = s[i] & 0xffff;
sb->sputn((char *)buf_, n*2);
}
/**
* Allocates a new, empty page in the file and returns the Page object.
* The newly allocated page is also assigned a frame in the buffer pool.
*
* @param file File object
* @param PageNo Page number. The number assigned to the page in the file is returned via this reference.
* @param page Reference to page pointer. The newly allocated in-memory Page object is returned via this reference.
*/
void BufMgr::allocPage(File* file, PageId &pageNo, Page*& page)
{
Page newPage = file->allocatePage();
allocBuf(fid);
bufPool[fid] = newPage;
page = &bufPool[fid];
pageNo = bufPool[fid].page_number();
hashTable->insert(file, pageNo, fid);
bufDescTable[fid].Set(file, pageNo);
}
EncodeOutputCharStream::EncodeOutputCharStream(OutputByteStream *byteStream,
const OutputCodingSystem *codingSystem)
: buf_(0),
byteStream_(byteStream),
escaper_(0),
ownedEncoder_(codingSystem->makeEncoder())
{
encoder_ = ownedEncoder_.pointer();
encoder_->setUnencodableHandler(this);
allocBuf(codingSystem->fixedBytesPerChar());
encoder_->startFile(byteStream_);
}
/**
* Allocates a new, empty page in the file and returns the Page object.
* The newly allocated page is also assigned a frame in the buffer pool.
*
* @param file File object
* @param PageNo Page number. The number assigned to the page in the file is returned via this reference.
* @param page Reference to page pointer. The newly allocated in-memory Page object is returned via this reference.
*/
void BufMgr::allocPage(File* file, PageId &pageNo, Page*& page)
{
FrameId frame;
allocBuf(frame);
bufPool[frame] = file->allocatePage();
pageNo = bufPool[frame].page_number();
bufDescTable[frame].Set(file, pageNo);
hashTable->insert(file, pageNo, frame);
page = &bufPool[frame];
}
void BufMgr::allocPage(File* file, PageId &pageNo, Page*& page)
{
FrameId frameNo;
allocBuf(frameNo);
bufPool[frameNo] = file->allocatePage();
//returns newly allocated page to the caller via the pageNo parameter
PageId pageNo1 = bufPool[frameNo].page_number();
hashTable->insert(file, pageNo1, frameNo);
bufDescTable[frameNo].Set(file, pageNo1);
//returns pointer to the frame via the page parameter
page = &bufPool[frameNo];
pageNo = pageNo1;
}
void EncodeOutputCharStream::open(OutputByteStream *byteStream,
const OutputCodingSystem *codingSystem)
{
if (byteStream_)
flush();
byteStream_ = byteStream;
ownedEncoder_ = codingSystem->makeEncoder();
encoder_ = ownedEncoder_.pointer();
encoder_->setUnencodableHandler(this);
delete [] buf_;
buf_ = 0;
ptr_ = end_ = buf_;
allocBuf(codingSystem->fixedBytesPerChar());
encoder_->startFile(byteStream_);
}
/**
* This function reads in a page. It will either be in the buffer pool or on disc.
* It first checks whether the page is already in the buffer pool
* by invoking the lookup() method on the hashtable to get a frame number.
* If it is not in buffer pool, Call allocBuf() to allocate a buffer frame
* and then call the method file->readPage() to read the page from disk
* into the buffer pool frame.
* @param file-a pointer to the file handle
* @param pageNo-the number of the page to be read
* @param page-a pointer to the page inside the frame
* @return Status-status information from function
**/
const Status BufMgr::readPage(File* file, const int pageNo, Page*& page) {
Status rc;
int frameNo = 0;
//Check to see if the page is in the buffer
rc = hashTable->lookup(file, pageNo, frameNo);
//if not OK or HASHNOTFOUND, than an error has been detected
if (rc != OK && rc != HASHNOTFOUND) {
return rc; //return error status message
}
if (rc == HASHNOTFOUND) {
//Page is not in the buffer pool.
int newFrameNo; //declaration for new frame pointer
// allocate a buffer frame for the page to be read
rc = allocBuf(newFrameNo);
if (rc != OK) {
return rc;
}
//map new buffer addition in the hashTable
rc = hashTable->insert(file, pageNo, newFrameNo);
//if not OK than we do not want to call Set()
if (rc != OK) {
return rc;
}
//set page from disc in buffer frame
bufTable[newFrameNo].Set(file, pageNo);
bufTable[newFrameNo].frameNo = newFrameNo; //update new frame number
rc = file->readPage(pageNo, &bufPool[newFrameNo]);
if (rc != OK) {
//Repair damage
disposePage(file, pageNo);
return rc;
}
page = &bufPool[newFrameNo]; //pointer to the page to be read
} else {
/*Page is in the buffer pool:
Set the appropriate refbit,
increment the pinCnt for the page,
and then return a pointer to the frame.*/
bufTable[frameNo].refbit = true;
bufTable[frameNo].pinCnt++;
page = &bufPool[frameNo]; //pointer to the page to be read
}
//Returns OK if no errors occurred.
return OK;
}// end function readPage
void IdentityEncoder::output(const Char *s, size_t n, streambuf *sb)
{
if (sizeof(Char) != sizeof(char)) {
allocBuf(n);
size_t j = 0;
for (size_t i = 0; i < n; i++) {
if (s[i] > UCHAR_MAX) {
sb->sputn(buf_, j);
j = 0;
handleUnencodable(s[i], sb);
}
else
buf_[j++] = char(s[i]);
}
sb->sputn(buf_, j);
}
else
sb->sputn((const char *)s, n);
}
/**
* Reads the given page from the file into a frame and returns the pointer to page.
* If the requested page is already present in the buffer pool pointer to that frame is returned
* otherwise a new frame is allocated from the buffer pool for reading the page.
*
* @param file File object
* @param PageNo Page number in the file to be read
* @param page Reference to page pointer. Used to fetch the Page object in which requested page from file is read in.
*/
void BufMgr::readPage(File* file, const PageId pageNo, Page*& page)
{
bool excepThrown = false;
try{
hashTable->lookup(file, pageNo, fid);
}
catch(HashNotFoundException e){
excepThrown = true;
allocBuf(fid);
Page tPage = file->readPage(pageNo);
bufPool[fid] = tPage;
hashTable->insert(file, pageNo, fid);
bufDescTable[fid].Set(file, pageNo);
}
if(!excepThrown){
bufDescTable[fid].refbit = true;
bufDescTable[fid].pinCnt++;
}
page = &bufPool[fid];
}
/*
* This method is to to allocate an empty page in the specified file.
*
* params: File* file, PageId &pageNo, Page*& page
*/
void BufMgr::allocPage(File* file, PageId &pageNo, Page*& page)
{
// get a new page and allocate frame
Page newPage = file->allocatePage();
pageNo = newPage.page_number();
FrameId frame = -1;
allocBuf(frame);
page = &(bufPool[frame]);
*page = file->readPage(pageNo);
// insert into hash table
hashTable->insert(file, pageNo, frame);
// call Set()
BufDesc* bufDesc = &(bufDescTable[frame]);
bufDesc->Set(file, pageNo);
//std::cout << "Allocated new page: " << frame << "\n";
}
/**
* Reads the given page from the file into a frame and returns the pointer to page.
* If the requested page is already present in the buffer pool pointer to that frame is returned
* otherwise a new frame is allocated from the buffer pool for reading the page.
*
* @param file File object
* @param PageNo Page number in the file to be read
* @param page Reference to page pointer. Used to fetch the Page object in which requested page from file is read in.
*/
void BufMgr::readPage(File* file, const PageId pageNo, Page*& page)
{
FrameId frame_check;
try{
hashTable->lookup(file, pageNo, frame_check);
}catch(HashNotFoundException ex){
//the page is not in the pool, so allocate one
FrameId frame_no;
allocBuf(frame_no);
bufPool[frame_no] = file->readPage(pageNo);
hashTable->insert(file, pageNo, frame_no);
bufDescTable[frame_no].Set(file, pageNo);
page = &bufPool[frame_no];
return;
}
bufDescTable[frame_check].pinCnt++;
bufDescTable[frame_check].refbit = true;
page = &bufPool[frame_check];
}
void BufMgr::readPage(File* file, const PageId pageNo, Page*& page)
{
FrameId frameNo;
try{
hashTable->lookup(file, pageNo, frameNo); // Case 2: Page is in the buffer pool
bufDescTable[frameNo].refbit = true;
bufDescTable[frameNo].pinCnt++;
// "Return a pointer to the frame containing the page via the page parameter"
page = &bufPool[frameNo];
}
catch(HashNotFoundException e){ // Case 1: Page is not in the buffer pool
allocBuf(frameNo);
bufStats.diskreads++;
bufPool[frameNo] = file->readPage(pageNo);
bufDescTable[frameNo].Set(file, pageNo);
//bufDescTable[frameNo].refbit = true;
// "Return a pointer to the frame containing the page via the page parameter"
page = &bufPool[frameNo];
hashTable->insert(file, pageNo, frameNo);
}
}
const Status BufMgr::allocPage(File* file, int& pageNo, Page*& page)
{
int frameNo;
// allocate a new page in the file
Status status = file->allocatePage(pageNo);
if (status != OK) return status;
// alloc a new frame
status = allocBuf(frameNo);
if (status != OK) return status;
// set up the entry properly
bufTable[frameNo].Set(file, pageNo);
page = &bufPool[frameNo];
// insert in thehash table
status = hashTable->insert(file, pageNo, frameNo);
if (status != OK) { return status; }
// cout << "allocated page " << pageNo << " to file " << file << "frame is: " << frameNo << endl;
return OK;
}
const Status BufMgr::allocPage(File* file, int& pageNo, Page*& page)
{
Status status = OK;
int frameNo = 0;
status = file->allocatePage(pageNo);
if (status != OK)
{
return status;
}
status = allocBuf(frameNo);
if (status != OK)
{
return status;
}
status = hashTable->insert(file, pageNo, frameNo);
if (status != OK)
{
return status;
}
bufTable[frameNo].Set(file, pageNo);
page = &(bufPool[frameNo]);
return status;
}
const Status BufMgr::readPage(File* file, const int PageNo, Page*& page)
{
// Your solution goes here
bufStats.accesses ++;
unsigned int frameno;
Status stats = bufMap.lookup(file, PageNo, frameno);
if(stats == OK){
bufTable[frameno].pinCnt++;
page = &(bufPool[frameno]);
return OK;
}else{
Status tempstatus2 = allocBuf(frameno);
if(tempstatus2 == BUFFEREXCEEDED) return BUFFEREXCEEDED;//I think this is how to add the BUFFEREXCEEDED error.
Page *pgpointer = &bufPool[frameno];
Status tempstatus = file->readPage(PageNo, pgpointer); //probably need to add error catch!
//cout << "Page pointer = " << pgpointer << endl;
if(tempstatus == UNIXERR){
return UNIXERR;
} else if (tempstatus == OK){
bufStats.diskreads ++;
bufTable[frameno].Set(file, PageNo);
if(bufMap.insert(file, PageNo, frameno) == BUFMAPERROR){
return BUFMAPERROR;
}
//page = &bufPool[frameno];
page = pgpointer;
//cout << "Buf pool test = " << bufPool[frameno].data << endl;
return OK;
}
}
return OK;
//BUFFEREXCEEDED error = ?
// do we need to write to the bufmap here?
// I don't think so...
}
const Status BufMgr::readPage(File* file, const int PageNo, Page*& page)
{
// check to see if it is already in the buffer pool
// cout << "readPage called on file.page " << file << "." << PageNo << endl;
int frameNo = 0;
Status status = hashTable->lookup(file, PageNo, frameNo);
if (status == OK)
{
// set the referenced bit
bufTable[frameNo].refbit = true;
bufTable[frameNo].pinCnt++;
page = &bufPool[frameNo];
}
else // not in the buffer pool, must allocate a new page
{
// alloc a new frame
status = allocBuf(frameNo);
if (status != OK) return status;
// read the page into the new frame
bufStats.diskreads++;
status = file->readPage(PageNo, &bufPool[frameNo]);
if (status != OK) return status;
// set up the entry properly
bufTable[frameNo].Set(file, PageNo);
page = &bufPool[frameNo];
// insert in the hash table
status = hashTable->insert(file, PageNo, frameNo);
if (status != OK) { return status; }
}
return OK;
}
