+++ /dev/null
-package org.apache.lucene.index;
-
-/**
- * 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 org.apache.lucene.index.FieldInfo.IndexOptions;
-import org.apache.lucene.store.IndexInput;
-
-import java.io.IOException;
-
-final class SegmentTermPositions
-extends SegmentTermDocs implements TermPositions {
- private IndexInput proxStream;
- private int proxCount;
- private int position;
-
- // the current payload length
- private int payloadLength;
- // indicates whether the payload of the current position has
- // been read from the proxStream yet
- private boolean needToLoadPayload;
-
- // these variables are being used to remember information
- // for a lazy skip
- private long lazySkipPointer = -1;
- private int lazySkipProxCount = 0;
-
- SegmentTermPositions(SegmentReader p) {
- super(p);
- this.proxStream = null; // the proxStream will be cloned lazily when nextPosition() is called for the first time
- }
-
- @Override
- final void seek(TermInfo ti, Term term) throws IOException {
- super.seek(ti, term);
- if (ti != null)
- lazySkipPointer = ti.proxPointer;
-
- lazySkipProxCount = 0;
- proxCount = 0;
- payloadLength = 0;
- needToLoadPayload = false;
- }
-
- @Override
- public final void close() throws IOException {
- super.close();
- if (proxStream != null) proxStream.close();
- }
-
- public final int nextPosition() throws IOException {
- if (indexOptions != IndexOptions.DOCS_AND_FREQS_AND_POSITIONS)
- // This field does not store positions, payloads
- return 0;
- // perform lazy skips if necessary
- lazySkip();
- proxCount--;
- return position += readDeltaPosition();
- }
-
- private final int readDeltaPosition() throws IOException {
- int delta = proxStream.readVInt();
- if (currentFieldStoresPayloads) {
- // if the current field stores payloads then
- // the position delta is shifted one bit to the left.
- // if the LSB is set, then we have to read the current
- // payload length
- if ((delta & 1) != 0) {
- payloadLength = proxStream.readVInt();
- }
- delta >>>= 1;
- needToLoadPayload = true;
- }
- return delta;
- }
-
- @Override
- protected final void skippingDoc() throws IOException {
- // we remember to skip a document lazily
- lazySkipProxCount += freq;
- }
-
- @Override
- public final boolean next() throws IOException {
- // we remember to skip the remaining positions of the current
- // document lazily
- lazySkipProxCount += proxCount;
-
- if (super.next()) { // run super
- proxCount = freq; // note frequency
- position = 0; // reset position
- return true;
- }
- return false;
- }
-
- @Override
- public final int read(final int[] docs, final int[] freqs) {
- throw new UnsupportedOperationException("TermPositions does not support processing multiple documents in one call. Use TermDocs instead.");
- }
-
-
- /** Called by super.skipTo(). */
- @Override
- protected void skipProx(long proxPointer, int payloadLength) throws IOException {
- // we save the pointer, we might have to skip there lazily
- lazySkipPointer = proxPointer;
- lazySkipProxCount = 0;
- proxCount = 0;
- this.payloadLength = payloadLength;
- needToLoadPayload = false;
- }
-
- private void skipPositions(int n) throws IOException {
- assert indexOptions == IndexOptions.DOCS_AND_FREQS_AND_POSITIONS;
- for (int f = n; f > 0; f--) { // skip unread positions
- readDeltaPosition();
- skipPayload();
- }
- }
-
- private void skipPayload() throws IOException {
- if (needToLoadPayload && payloadLength > 0) {
- proxStream.seek(proxStream.getFilePointer() + payloadLength);
- }
- needToLoadPayload = false;
- }
-
- // It is not always necessary to move the prox pointer
- // to a new document after the freq pointer has been moved.
- // Consider for example a phrase query with two terms:
- // the freq pointer for term 1 has to move to document x
- // to answer the question if the term occurs in that document. But
- // only if term 2 also matches document x, the positions have to be
- // read to figure out if term 1 and term 2 appear next
- // to each other in document x and thus satisfy the query.
- // So we move the prox pointer lazily to the document
- // as soon as positions are requested.
- private void lazySkip() throws IOException {
- if (proxStream == null) {
- // clone lazily
- proxStream = (IndexInput) parent.core.proxStream.clone();
- }
-
- // we might have to skip the current payload
- // if it was not read yet
- skipPayload();
-
- if (lazySkipPointer != -1) {
- proxStream.seek(lazySkipPointer);
- lazySkipPointer = -1;
- }
-
- if (lazySkipProxCount != 0) {
- skipPositions(lazySkipProxCount);
- lazySkipProxCount = 0;
- }
- }
-
- public int getPayloadLength() {
- return payloadLength;
- }
-
- public byte[] getPayload(byte[] data, int offset) throws IOException {
- if (!needToLoadPayload) {
- throw new IOException("Either no payload exists at this term position or an attempt was made to load it more than once.");
- }
-
- // read payloads lazily
- byte[] retArray;
- int retOffset;
- if (data == null || data.length - offset < payloadLength) {
- // the array is too small to store the payload data,
- // so we allocate a new one
- retArray = new byte[payloadLength];
- retOffset = 0;
- } else {
- retArray = data;
- retOffset = offset;
- }
- proxStream.readBytes(retArray, retOffset, payloadLength);
- needToLoadPayload = false;
- return retArray;
- }
-
- public boolean isPayloadAvailable() {
- return needToLoadPayload && payloadLength > 0;
- }
-
-}
fnp / pylucene.git / blobdiff