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 java.io.IOException;
import org.apache.lucene.store.IndexInput;
final class SegmentTermEnum extends TermEnum implements Cloneable {
private IndexInput input;
FieldInfos fieldInfos;
long size;
long position = -1;
private TermBuffer termBuffer = new TermBuffer();
private TermBuffer prevBuffer = new TermBuffer();
private TermBuffer scanBuffer = new TermBuffer(); // used for scanning
private TermInfo termInfo = new TermInfo();
private int format;
private boolean isIndex = false;
long indexPointer = 0;
int indexInterval;
int skipInterval;
int maxSkipLevels;
private int formatM1SkipInterval;
SegmentTermEnum(IndexInput i, FieldInfos fis, boolean isi)
throws CorruptIndexException, IOException {
input = i;
fieldInfos = fis;
isIndex = isi;
maxSkipLevels = 1; // use single-level skip lists for formats > -3
int firstInt = input.readInt();
if (firstInt >= 0) {
// original-format file, without explicit format version number
format = 0;
size = firstInt;
// back-compatible settings
indexInterval = 128;
skipInterval = Integer.MAX_VALUE; // switch off skipTo optimization
} else {
// we have a format version number
format = firstInt;
// check that it is a format we can understand
if (format < TermInfosWriter.FORMAT_CURRENT)
throw new CorruptIndexException("Unknown format version:" + format + " expected " + TermInfosWriter.FORMAT_CURRENT + " or higher");
size = input.readLong(); // read the size
if(format == -1){
if (!isIndex) {
indexInterval = input.readInt();
formatM1SkipInterval = input.readInt();
}
// switch off skipTo optimization for file format prior to 1.4rc2 in order to avoid a bug in
// skipTo implementation of these versions
skipInterval = Integer.MAX_VALUE;
} else {
indexInterval = input.readInt();
skipInterval = input.readInt();
if (format <= TermInfosWriter.FORMAT) {
// this new format introduces multi-level skipping
maxSkipLevels = input.readInt();
}
}
assert indexInterval > 0: "indexInterval=" + indexInterval + " is negative; must be > 0";
assert skipInterval > 0: "skipInterval=" + skipInterval + " is negative; must be > 0";
}
if (format > TermInfosWriter.FORMAT_VERSION_UTF8_LENGTH_IN_BYTES) {
termBuffer.setPreUTF8Strings();
scanBuffer.setPreUTF8Strings();
prevBuffer.setPreUTF8Strings();
}
}
@Override
protected Object clone() {
SegmentTermEnum clone = null;
try {
clone = (SegmentTermEnum) super.clone();
} catch (CloneNotSupportedException e) {}
clone.input = (IndexInput) input.clone();
clone.termInfo = new TermInfo(termInfo);
clone.termBuffer = (TermBuffer)termBuffer.clone();
clone.prevBuffer = (TermBuffer)prevBuffer.clone();
clone.scanBuffer = new TermBuffer();
return clone;
}
final void seek(long pointer, long p, Term t, TermInfo ti)
throws IOException {
input.seek(pointer);
position = p;
termBuffer.set(t);
prevBuffer.reset();
termInfo.set(ti);
}
/** Increments the enumeration to the next element. True if one exists.*/
@Override
public final boolean next() throws IOException {
if (position++ >= size - 1) {
prevBuffer.set(termBuffer);
termBuffer.reset();
return false;
}
prevBuffer.set(termBuffer);
termBuffer.read(input, fieldInfos);
termInfo.docFreq = input.readVInt(); // read doc freq
termInfo.freqPointer += input.readVLong(); // read freq pointer
termInfo.proxPointer += input.readVLong(); // read prox pointer
if(format == -1){
// just read skipOffset in order to increment file pointer;
// value is never used since skipTo is switched off
if (!isIndex) {
if (termInfo.docFreq > formatM1SkipInterval) {
termInfo.skipOffset = input.readVInt();
}
}
}
else{
if (termInfo.docFreq >= skipInterval)
termInfo.skipOffset = input.readVInt();
}
if (isIndex)
indexPointer += input.readVLong(); // read index pointer
return true;
}
/** Optimized scan, without allocating new terms.
* Return number of invocations to next(). */
final int scanTo(Term term) throws IOException {
scanBuffer.set(term);
int count = 0;
while (scanBuffer.compareTo(termBuffer) > 0 && next()) {
count++;
}
return count;
}
/** Returns the current Term in the enumeration.
Initially invalid, valid after next() called for the first time.*/
@Override
public final Term term() {
return termBuffer.toTerm();
}
/** Returns the previous Term enumerated. Initially null.*/
final Term prev() {
return prevBuffer.toTerm();
}
/** Returns the current TermInfo in the enumeration.
Initially invalid, valid after next() called for the first time.*/
final TermInfo termInfo() {
return new TermInfo(termInfo);
}
/** Sets the argument to the current TermInfo in the enumeration.
Initially invalid, valid after next() called for the first time.*/
final void termInfo(TermInfo ti) {
ti.set(termInfo);
}
/** Returns the docFreq from the current TermInfo in the enumeration.
Initially invalid, valid after next() called for the first time.*/
@Override
public final int docFreq() {
return termInfo.docFreq;
}
/* Returns the freqPointer from the current TermInfo in the enumeration.
Initially invalid, valid after next() called for the first time.*/
final long freqPointer() {
return termInfo.freqPointer;
}
/* Returns the proxPointer from the current TermInfo in the enumeration.
Initially invalid, valid after next() called for the first time.*/
final long proxPointer() {
return termInfo.proxPointer;
}
/** Closes the enumeration to further activity, freeing resources. */
@Override
public final void close() throws IOException {
input.close();
}
}