/**
* Returns a pointer or reference to the readonly record associated with tid
*
* @param tid: the tuple ID
*
* @return rtrn: the record
*/
Record* SPSegment::lookup(TID tid) {
Record* rtrn;
try {
if (tid.pageId >= 0 && tid.slotId >= 0) {
// read slotted page out of memory map
if (spMap.count(tid.pageId) > 0) {
SlottedPage* sp = spMap.at(tid.pageId);
rtrn = sp->lookupRecord(tid.slotId);
}
// if not available read from frame
else {
// writes frame into map too
SlottedPage* sp = readFromFrame(tid.pageId);
if (sp != NULL) {
rtrn = sp->lookupRecord(tid.slotId);
} else {
throw invalid_argument("No page found by given tid");
}
}
} else {
throw invalid_argument("Given tid is invalid");
}
// in case of record is a redirection, lookup for redirected data record
if (!rtrn->isDataRecord()) {
rtrn = lookup(rtrn->redirection);
}
} catch (const invalid_argument& e) {
cerr << "Invalid argument @lookup segment: " << e.what() << endl;
rtrn = NULL;
}
return rtrn;
}
/**
* Deletes the record pointed to by tid
*
* @param tid: the tuple ID
*
* @return rtrn: whether successfully or not
*/
bool SPSegment::remove(TID tid) {
bool rtrn = true;
try {
if (tid.pageId >= 0 && tid.slotId >= 0) {
if (spMap.count(tid.pageId) > 0) {
SlottedPage* sp = spMap.at(tid.pageId);
Record* recordToRemove = sp->lookupRecord(tid.slotId);
// in case of record to remove is a redirection, first remove remote record
if (!recordToRemove->isDataRecord()) {
remove(recordToRemove->redirection);
}
sp->removeRecord(tid.slotId);
// write changes back to disk
if (!writeToFrame(sp, tid.pageId)) {
cerr << "Cannot write slotted page into frame" << endl;
}
}
} else {
throw invalid_argument("Given tid is invalid");
}
} catch (const invalid_argument& e) {
cerr << "Invalid argument @remove segment: " << e.what() << endl;
rtrn = false;
}
return rtrn;
}
