org.apache.datasketches.tuple.arrayofdoubles.DirectArrayOfDoublesSketchIterator Maven / Gradle / Ivy
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Core sketch algorithms used alone and by other Java repositories in the DataSketches library.
/*
* 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.
*/
package org.apache.datasketches.tuple.arrayofdoubles;
import org.apache.datasketches.memory.Memory;
/**
* Iterator over the off-heap, Direct tuple sketch of type ArrayOfDoubles (compact or hash table).
* This implementation uses data in a given Memory that is owned and managed by the caller.
* This Memory can be off-heap, which if managed properly will greatly reduce the need for
* the JVM to perform garbage collection.
*/
final class DirectArrayOfDoublesSketchIterator implements ArrayOfDoublesSketchIterator {
private Memory mem_;
private int offset_;
private int numEntries_;
private int numValues_;
private int i_;
private static final int SIZE_OF_KEY_BYTES = 8;
private static final int SIZE_OF_VALUE_BYTES = 8;
DirectArrayOfDoublesSketchIterator(final Memory mem, final int offset, final int numEntries,
final int numValues) {
mem_ = mem;
offset_ = offset;
numEntries_ = numEntries;
numValues_ = numValues;
i_ = -1;
}
@Override
public boolean next() {
i_++;
while (i_ < numEntries_) {
if (mem_.getLong(offset_ + ((long) SIZE_OF_KEY_BYTES * i_)) != 0) { return true; }
i_++;
}
return false;
}
@Override
public long getKey() {
return mem_.getLong(offset_ + ((long) SIZE_OF_KEY_BYTES * i_));
}
@Override
public double[] getValues() {
if (numValues_ == 1) {
return new double[] {
mem_.getDouble(offset_ + ((long) SIZE_OF_KEY_BYTES * numEntries_)
+ ((long) SIZE_OF_VALUE_BYTES * i_)) };
}
final double[] array = new double[numValues_];
mem_.getDoubleArray(offset_ + ((long) SIZE_OF_KEY_BYTES * numEntries_)
+ ((long) SIZE_OF_VALUE_BYTES * i_ * numValues_), array, 0, numValues_);
return array;
}
}
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