+++ /dev/null
-package org.apache.lucene.search;
-
-/**
- * Licensed to the Apache Software Foundation (ASF) under one or more
- * contributor license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright ownership.
- * The ASF licenses this file to You under the Apache License, Version 2.0
- * (the "License"); you may not use this file except in compliance with
- * the License. You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-import java.io.IOException;
-import java.util.Arrays;
-
-import org.apache.lucene.index.*;
-
-final class ExactPhraseScorer extends Scorer {
- private final byte[] norms;
- private final float value;
-
- private static final int SCORE_CACHE_SIZE = 32;
- private final float[] scoreCache = new float[SCORE_CACHE_SIZE];
-
- private final int endMinus1;
-
- private final static int CHUNK = 4096;
-
- private int gen;
- private final int[] counts = new int[CHUNK];
- private final int[] gens = new int[CHUNK];
-
- boolean noDocs;
-
- private final static class ChunkState {
- final TermPositions posEnum;
- final int offset;
- final boolean useAdvance;
- int posUpto;
- int posLimit;
- int pos;
- int lastPos;
-
- public ChunkState(TermPositions posEnum, int offset, boolean useAdvance) {
- this.posEnum = posEnum;
- this.offset = offset;
- this.useAdvance = useAdvance;
- }
- }
-
- private final ChunkState[] chunkStates;
-
- private int docID = -1;
- private int freq;
-
- ExactPhraseScorer(Weight weight, PhraseQuery.PostingsAndFreq[] postings,
- Similarity similarity, byte[] norms) throws IOException {
- super(similarity, weight);
- this.norms = norms;
- this.value = weight.getValue();
-
- chunkStates = new ChunkState[postings.length];
-
- endMinus1 = postings.length-1;
-
- for(int i=0;i<postings.length;i++) {
-
- // Coarse optimization: advance(target) is fairly
- // costly, so, if the relative freq of the 2nd
- // rarest term is not that much (> 1/5th) rarer than
- // the first term, then we just use .nextDoc() when
- // ANDing. This buys ~15% gain for phrases where
- // freq of rarest 2 terms is close:
- final boolean useAdvance = postings[i].docFreq > 5*postings[0].docFreq;
- chunkStates[i] = new ChunkState(postings[i].postings, -postings[i].position, useAdvance);
- if (i > 0 && !postings[i].postings.next()) {
- noDocs = true;
- return;
- }
- }
-
- for (int i = 0; i < SCORE_CACHE_SIZE; i++) {
- scoreCache[i] = getSimilarity().tf((float) i) * value;
- }
- }
-
- @Override
- public int nextDoc() throws IOException {
- while(true) {
-
- // first (rarest) term
- if (!chunkStates[0].posEnum.next()) {
- docID = DocIdSetIterator.NO_MORE_DOCS;
- return docID;
- }
-
- final int doc = chunkStates[0].posEnum.doc();
-
- // not-first terms
- int i = 1;
- while(i < chunkStates.length) {
- final ChunkState cs = chunkStates[i];
- int doc2 = cs.posEnum.doc();
- if (cs.useAdvance) {
- if (doc2 < doc) {
- if (!cs.posEnum.skipTo(doc)) {
- docID = DocIdSetIterator.NO_MORE_DOCS;
- return docID;
- } else {
- doc2 = cs.posEnum.doc();
- }
- }
- } else {
- int iter = 0;
- while(doc2 < doc) {
- // safety net -- fallback to .skipTo if we've
- // done too many .nextDocs
- if (++iter == 50) {
- if (!cs.posEnum.skipTo(doc)) {
- docID = DocIdSetIterator.NO_MORE_DOCS;
- return docID;
- } else {
- doc2 = cs.posEnum.doc();
- }
- break;
- } else {
- if (cs.posEnum.next()) {
- doc2 = cs.posEnum.doc();
- } else {
- docID = DocIdSetIterator.NO_MORE_DOCS;
- return docID;
- }
- }
- }
- }
- if (doc2 > doc) {
- break;
- }
- i++;
- }
-
- if (i == chunkStates.length) {
- // this doc has all the terms -- now test whether
- // phrase occurs
- docID = doc;
-
- freq = phraseFreq();
- if (freq != 0) {
- return docID;
- }
- }
- }
- }
-
- @Override
- public int advance(int target) throws IOException {
-
- // first term
- if (!chunkStates[0].posEnum.skipTo(target)) {
- docID = DocIdSetIterator.NO_MORE_DOCS;
- return docID;
- }
- int doc = chunkStates[0].posEnum.doc();
-
- while(true) {
-
- // not-first terms
- int i = 1;
- while(i < chunkStates.length) {
- int doc2 = chunkStates[i].posEnum.doc();
- if (doc2 < doc) {
- if (!chunkStates[i].posEnum.skipTo(doc)) {
- docID = DocIdSetIterator.NO_MORE_DOCS;
- return docID;
- } else {
- doc2 = chunkStates[i].posEnum.doc();
- }
- }
- if (doc2 > doc) {
- break;
- }
- i++;
- }
-
- if (i == chunkStates.length) {
- // this doc has all the terms -- now test whether
- // phrase occurs
- docID = doc;
- freq = phraseFreq();
- if (freq != 0) {
- return docID;
- }
- }
-
- if (!chunkStates[0].posEnum.next()) {
- docID = DocIdSetIterator.NO_MORE_DOCS;
- return docID;
- } else {
- doc = chunkStates[0].posEnum.doc();
- }
- }
- }
-
- @Override
- public String toString() {
- return "ExactPhraseScorer(" + weight + ")";
- }
-
- @Override
- public float freq() {
- return freq;
- }
-
- @Override
- public int docID() {
- return docID;
- }
-
- @Override
- public float score() throws IOException {
- final float raw; // raw score
- if (freq < SCORE_CACHE_SIZE) {
- raw = scoreCache[freq];
- } else {
- raw = getSimilarity().tf((float) freq) * value;
- }
- return norms == null ? raw : raw * getSimilarity().decodeNormValue(norms[docID]); // normalize
- }
-
- private int phraseFreq() throws IOException {
-
- freq = 0;
-
- // init chunks
- for(int i=0;i<chunkStates.length;i++) {
- final ChunkState cs = chunkStates[i];
- cs.posLimit = cs.posEnum.freq();
- cs.pos = cs.offset + cs.posEnum.nextPosition();
- cs.posUpto = 1;
- cs.lastPos = -1;
- }
-
- int chunkStart = 0;
- int chunkEnd = CHUNK;
-
- // process chunk by chunk
- boolean end = false;
-
- // TODO: we could fold in chunkStart into offset and
- // save one subtract per pos incr
-
- while(!end) {
-
- gen++;
-
- if (gen == 0) {
- // wraparound
- Arrays.fill(gens, 0);
- gen++;
- }
-
- // first term
- {
- final ChunkState cs = chunkStates[0];
- while(cs.pos < chunkEnd) {
- if (cs.pos > cs.lastPos) {
- cs.lastPos = cs.pos;
- final int posIndex = cs.pos - chunkStart;
- counts[posIndex] = 1;
- assert gens[posIndex] != gen;
- gens[posIndex] = gen;
- }
-
- if (cs.posUpto == cs.posLimit) {
- end = true;
- break;
- }
- cs.posUpto++;
- cs.pos = cs.offset + cs.posEnum.nextPosition();
- }
- }
-
- // middle terms
- boolean any = true;
- for(int t=1;t<endMinus1;t++) {
- final ChunkState cs = chunkStates[t];
- any = false;
- while(cs.pos < chunkEnd) {
- if (cs.pos > cs.lastPos) {
- cs.lastPos = cs.pos;
- final int posIndex = cs.pos - chunkStart;
- if (posIndex >= 0 && gens[posIndex] == gen && counts[posIndex] == t) {
- // viable
- counts[posIndex]++;
- any = true;
- }
- }
-
- if (cs.posUpto == cs.posLimit) {
- end = true;
- break;
- }
- cs.posUpto++;
- cs.pos = cs.offset + cs.posEnum.nextPosition();
- }
-
- if (!any) {
- break;
- }
- }
-
- if (!any) {
- // petered out for this chunk
- chunkStart += CHUNK;
- chunkEnd += CHUNK;
- continue;
- }
-
- // last term
-
- {
- final ChunkState cs = chunkStates[endMinus1];
- while(cs.pos < chunkEnd) {
- if (cs.pos > cs.lastPos) {
- cs.lastPos = cs.pos;
- final int posIndex = cs.pos - chunkStart;
- if (posIndex >= 0 && gens[posIndex] == gen && counts[posIndex] == endMinus1) {
- freq++;
- }
- }
-
- if (cs.posUpto == cs.posLimit) {
- end = true;
- break;
- }
- cs.posUpto++;
- cs.pos = cs.offset + cs.posEnum.nextPosition();
- }
- }
-
- chunkStart += CHUNK;
- chunkEnd += CHUNK;
- }
-
- return freq;
- }
-}
fnp / pylucene.git / blobdiff