/*
* 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.imhotep.metrics;
import com.indeed.flamdex.api.IntValueLookup;
import com.indeed.imhotep.MemoryReserver;
import com.indeed.imhotep.api.ImhotepOutOfMemoryException;
import java.util.BitSet;
/**
* @author dwahler
*/
public class CachedInterleavedMetrics {
private final MemoryReserver memory;
private final int numDocs, stride;
private long[] interleavedData;
private final BitSet closed;
private boolean released;
public CachedInterleavedMetrics(MemoryReserver memory, int numDocs, IntValueLookup... lookups) throws ImhotepOutOfMemoryException {
this.memory = memory;
this.numDocs = numDocs;
this.stride = lookups.length;
if (!memory.claimMemory(numDocs * 8L * stride)) {
throw new ImhotepOutOfMemoryException();
}
interleavedData = new long[numDocs * stride];
fillValues(lookups);
closed = new BitSet(stride);
}
public IntValueLookup[] getLookups() {
final IntValueLookup[] result = new IntValueLookup[stride];
for (int i = 0; i < stride; i++) {
result[i] = new InterleavedLookup(i);
}
return result;
}
private void fillValues(IntValueLookup... lookups) {
final int BUFFER_SIZE = 8192;
final int[] idBuffer = new int[BUFFER_SIZE];
final long[] valBuffer = new long[BUFFER_SIZE];
for (int start = 0; start < numDocs; start += BUFFER_SIZE) {
final int end = Math.min(numDocs, start+BUFFER_SIZE);
final int n = end-start;
for (int i = 0; i < n; i++) {
idBuffer[i] = start + i;
}
for (int offset = 0; offset < lookups.length; offset++) {
lookups[offset].lookup(idBuffer, valBuffer, n);
for (int i = 0; i < n; i++) {
interleavedData[(i+start)*stride+offset] = valBuffer[i];
}
}
}
}
private void closeLookup(int offset) {
closed.set(offset);
if (closed.nextClearBit(0) == stride && !released) {
// all lookups are closed; release memory from pool
released = true;
interleavedData = null;
memory.releaseMemory(numDocs * 8L * stride);
}
}
private class InterleavedLookup implements IntValueLookup {
private final int offset;
private InterleavedLookup(int offset) {
this.offset = offset;
}
@Override
public long getMin() {
return Long.MIN_VALUE; // TODO compute this
}
@Override
public long getMax() {
return Long.MAX_VALUE; // TODO compute this;
}
@Override
public void lookup(int[] docIds, long[] values, int n) {
final long[] interleavedData = CachedInterleavedMetrics.this.interleavedData;
final int stride = CachedInterleavedMetrics.this.stride;
final int offset = this.offset;
for (int i = 0; i < n; i++) {
values[i] = interleavedData[docIds[i]*stride + offset];
}
}
@Override
public long memoryUsed() {
return numDocs * 8L;
}
@Override
public void close() {
closeLookup(offset);
}
}
}