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/*------------------------------------------------------------------------------
* Copyright (C) 2003-2006 Ben van Klinken and the CLucene Team
*
* Distributable under the terms of either the Apache License (Version 2.0) or
* the GNU Lesser General Public License, as specified in the COPYING file.
------------------------------------------------------------------------------*/
#include "CLucene/StdHeader.h"
#include "PhraseScorer.h"
#include "PhraseQueue.h"
#include "PhrasePositions.h"
#include "Scorer.h"
#include "Similarity.h"
CL_NS_USE(index)
CL_NS_USE(util)
CL_NS_DEF(search)
PhraseScorer::PhraseScorer(Weight* weight, TermPositions** tps,
int32_t* positions, Similarity* similarity, uint8_t* norms):
Scorer(similarity)
{
//Func - Constructor
//Pre - tps != NULL and is an array of TermPositions
// tpsLength >= 0
// n != NULL
//Post - The instance has been created
CND_PRECONDITION(tps != NULL,"tps is NULL");
//norms are only used if phraseFreq returns more than 0.0
//phraseFreq should only return more than 0.0 if norms != NULL
//CND_PRECONDITION(n != NULL,"n is NULL");
firstTime = true;
more = true;
this->norms = norms;
this->weight = weight;
this->value = weight->getValue();
//reset internal pointers
first = NULL;
last = NULL;
//use pq to build a sorted list of PhrasePositions
int32_t i = 0;
while(tps[i] != NULL){
PhrasePositions *pp = _CLNEW PhrasePositions(tps[i], positions[i]);
CND_CONDITION(pp != NULL,"Could not allocate memory for pp");
//Store PhrasePos into the PhrasePos pq
if (last != NULL) { // add next to end of list
last->_next = pp;
} else
first = pp;
last = pp;
i++;
}
pq = _CLNEW PhraseQueue(i); //i==tps.length
CND_CONDITION(pq != NULL,"Could not allocate memory for pq");
}
PhraseScorer::~PhraseScorer() {
//Func - Destructor
//Pre - true
//Post - The instance has been destroyed
//The PhraseQueue pq (which is a PriorityQueue) pq is actually empty at present, the elements
//having been transferred by pqToList() to the linked list starting with
//first. The nodes of that linked list are deleted by the destructor of
//first, rather than the destructor of pq.
_CLDELETE(first);
_CLDELETE(pq);
}
bool PhraseScorer::next(){
if (firstTime) {
init();
firstTime = false;
} else if (more) {
more = last->next(); // trigger further scanning
}
return doNext();
}
// 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
}
qreal PhraseScorer::score(){
//System.out.println("scoring " + first.doc);
qreal raw = getSimilarity()->tf(freq) * value; // raw score
return raw * Similarity::decodeNorm(norms[first->doc]); // normalize
}
bool PhraseScorer::skipTo(int32_t target) {
for (PhrasePositions* pp = first; more && pp != NULL; pp = pp->_next) {
more = pp->skipTo(target);
}
if (more)
sort(); // re-sort
return doNext();
}
void PhraseScorer::init() {
for (PhrasePositions* pp = first; more && pp != NULL; pp = pp->_next)
more = pp->next();
if(more)
sort();
}
void PhraseScorer::sort() {
pq->clear();
for (PhrasePositions* pp = first; pp != NULL; pp = pp->_next)
pq->put(pp);
pqToList();
}
void PhraseScorer::pqToList(){
//Func - Transfers the PhrasePositions from the PhraseQueue pq to
// the PhrasePositions list with first as its first element
//Pre - pq != NULL
// first = NULL
// last = NULL
//Post - All PhrasePositions have been transfered to the list
// of PhrasePositions of which the first element is pointed to by first
// and the last element is pointed to by last
CND_PRECONDITION(pq != NULL,"pq is NULL");
last = first = NULL;
PhrasePositions* PhrasePos = NULL;
//As long pq is not empty
while (pq->top() != NULL){
//Pop a PhrasePositions instance
PhrasePos = pq->pop();
// add next to end of list
if (last != NULL) {
last->_next = PhrasePos;
} else {
first = PhrasePos;
}
//Let last point to the new last PhrasePositions instance just added
last = PhrasePos;
//Reset the next of last to NULL
last->_next = NULL;
}
//Check to see that pq is empty now
CND_CONDITION(pq->size()==0, "pq is not empty while it should be");
}
void PhraseScorer::firstToLast(){
//Func - Moves first to the end of the list
//Pre - first is NULL or points to an PhrasePositions Instance
// last is NULL or points to an PhrasePositions Instance
// first and last both are NULL or both are not NULL
//Post - The first element has become the last element in the list
CND_PRECONDITION(((first==NULL && last==NULL) ||(first !=NULL && last != NULL)),
"Either first or last is NULL but not both");
//Check if first and last are valid pointers
if(first && last){
last->_next = first;
last = first;
first = first->_next;
last->_next = NULL;
}
}
void PhraseScorer::explain(int32_t _doc, Explanation* tfExplanation) {
while (next() && doc() < _doc){
}
qreal phraseFreq = (doc() == _doc) ? freq : 0.0f;
tfExplanation->setValue(getSimilarity()->tf(phraseFreq));
StringBuffer buf;
buf.append(_T("tf(phraseFreq="));
buf.appendFloat(phraseFreq,2);
buf.append(_T(")"));
tfExplanation->setDescription(buf.getBuffer());
}
TCHAR* PhraseScorer::toString() {
StringBuffer buf;
buf.append(_T("scorer("));
TCHAR* tmp = weight->toString();
buf.append(tmp);
_CLDELETE_CARRAY(tmp);
buf.append(_T(")"));
return buf.toString();
}
CL_NS_END
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