/*
* Copyright (C) 2014 Indeed Inc.
*
* Licensed 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.
*/
package com.indeed.flamdex.simple;
import com.indeed.util.core.io.Closeables2;
import com.indeed.util.core.reference.SharedReference;
import com.indeed.flamdex.api.TermDocIterator;
import com.indeed.util.mmap.DirectMemory;
import com.indeed.util.mmap.MMapBuffer;
import org.apache.log4j.Logger;
import java.io.IOException;
/**
* @author jplaisance
*/
public abstract class NativeTermDocIterator implements TermDocIterator {
private static final Logger log = Logger.getLogger(NativeTermDocIterator.class);
protected abstract boolean bufferNext();
protected abstract long offset();
protected abstract int lastDocFreq();
protected abstract void poll();
private final SharedReference<MMapBuffer> file;
private final DirectMemory memory;
private int bufferedTerms = 0;
private int termIndex = 0;
private final int[] docFreqBuffer = new int[128];
private int currentTermDocsRemaining = 0;
private int lastDoc = 0;
private final NativeDocIdBuffer buffer = new NativeDocIdBuffer();
private boolean closed = false;
NativeTermDocIterator(String filename, MapCache mapCache) throws IOException {
file = mapCache.copyOrOpen(filename);
memory = file.get().memory();
}
@Override
public final boolean nextTerm() {
if (currentTermDocsRemaining > 0) throw new IllegalStateException("must iterate over entire doc list for previous term before calling nextTerm");
final int nextTermIndex = termIndex+1;
if (nextTermIndex < bufferedTerms) {
termIndex = nextTermIndex;
currentTermDocsRemaining = docFreqBuffer[termIndex];
poll();
lastDoc = 0;
return true;
}
if (bufferedTerms > 0) {
poll();
}
long totalDocFreq = 0;
termIndex = 0;
bufferedTerms = 0;
if (!bufferNext()) return false;
final long offset = offset();
do {
docFreqBuffer[bufferedTerms] = lastDocFreq();
totalDocFreq += lastDocFreq();
bufferedTerms++;
} while (bufferedTerms < docFreqBuffer.length && bufferNext());
currentTermDocsRemaining = docFreqBuffer[termIndex];
lastDoc = 0;
buffer.reset(memory.getAddress()+offset, totalDocFreq);
return true;
}
@Override
public final int docFreq() {
return docFreqBuffer[termIndex];
}
@Override
public final int fillDocIdBuffer(final int[] docIdBuffer) {
final int n = buffer.fillDocIdBuffer(docIdBuffer, Math.min(docIdBuffer.length, currentTermDocsRemaining));
for (int i = 0; i < n; i++) {
lastDoc += docIdBuffer[i];
docIdBuffer[i] = lastDoc;
}
currentTermDocsRemaining -= n;
return n;
}
@Override
public void close() {
if (!closed) {
closed = true;
Closeables2.closeQuietly(file, log);
Closeables2.closeQuietly(buffer, log);
}
}
}