bool NearSpansUnordered::next()
{
if (firstTime)
{
initList(true);
listToQueue(); // initialize queue
firstTime = false;
}
else if (more)
{
if (min()->next()) // trigger further scanning
queue->updateTop(); // maintain queue
else
more = false;
}
while (more)
{
bool queueStale = false;
if (min()->doc() != max->doc()) // maintain list
{
queueToList();
queueStale = true;
}
// skip to doc with all clauses
while (more && first->doc() < last->doc())
{
more = first->skipTo(last->doc()); // skip first upto last
firstToLast(); // and move it to the end
queueStale = true;
}
if (!more)
return false;
// found doc with all clauses
if (queueStale) // maintain the queue
{
listToQueue();
queueStale = false;
}
if (atMatch())
return true;
more = min()->next();
if (more)
queue->updateTop(); // maintain queue
}
return false; // no more matches
}
qreal ExactPhraseScorer::phraseFreq(){
//Func - Returns the freqency of the phrase
//Pre - first != NULL
// last != NULL
// pq != NULL
// size of the PhraseQueue pq is 0
//Post - The frequency of the phrase has been returned
CND_PRECONDITION(first != NULL,"first is NULL");
CND_PRECONDITION(last != NULL,"last is NULL");
CND_PRECONDITION(pq != NULL,"pq is NULL");
CND_PRECONDITION(pq->size()==0,"pq is not empty");
//build pq from list
//Add the nodes of the list of PhrasePositions and store them
//into the PhraseQueue pq so it can used to build
//a list of sorted nodes
for (PhrasePositions* pp = first; pp != NULL; pp = pp->_next) {
//Read the first TermPosition of the current PhrasePositions pp
pp->firstPosition();
//Store the current PhrasePositions pp into the PhraseQueue pq
pq->put(pp);
}
//pqToList requires that first and last be NULL when it's called.
//This is done at the beginning of pqToList()
//In this case, the nodes of the linked list are referenced by pq (see
//above loop), so we can clear our pointers to the head and tail of the
//linked list without fear of leaking the nodes.
//rebuild list from pq
pqToList();
//Initialize freq at 0
int32_t freq = 0;
//find position with all terms
do {
//scan forward in first
while (first->position < last->position){
do{
if (!first->nextPosition()){
return (qreal)freq;
}
} while (first->position < last->position);
//Make the current first node the last node in the list
firstToLast();
}
//all equal: a match has been found
freq++;
} while (last->nextPosition());
return (qreal)freq;
}
// next without initial increment
bool PhraseScorer::doNext() {
while (more) {
while (more && first->doc < last->doc) { // find doc w/ all the terms
more = first->skipTo(last->doc); // skip first upto last
firstToLast(); // and move it to the end
}
if (more) {
// found a doc with all of the terms
freq = phraseFreq(); // check for phrase
if (freq == 0.0f) // no match
more = last->next(); // trigger further scanning
else
return true; // found a match
}
}
return false; // no more matches
}
