io.trino.array.SliceBigArray Maven / Gradle / Ivy
/*
* 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 io.trino.array;
import io.airlift.slice.Slice;
import static io.airlift.slice.SizeOf.instanceSize;
public final class SliceBigArray
{
private static final int INSTANCE_SIZE = instanceSize(SliceBigArray.class);
private static final int SLICE_INSTANCE_SIZE = instanceSize(Slice.class);
private final ObjectBigArray array;
private final ReferenceCountMap trackedSlices = new ReferenceCountMap();
private long sizeOfSlices;
public SliceBigArray()
{
array = new ObjectBigArray<>();
}
public SliceBigArray(Slice slice)
{
array = new ObjectBigArray<>(slice);
}
/**
* Returns the size of this big array in bytes.
*/
public long sizeOf()
{
return INSTANCE_SIZE + array.sizeOf() + sizeOfSlices + trackedSlices.sizeOf();
}
/**
* Returns the element of this big array at specified index.
*
* @param index a position in this big array.
* @return the element of this big array at the specified position.
*/
public Slice get(long index)
{
return array.get(index);
}
/**
* Sets the element of this big array at specified index.
*
* @param index a position in this big array.
*/
public void set(long index, Slice value)
{
updateRetainedSize(array.getAndSet(index, value), value);
}
/**
* Ensures this big array is at least the specified length. If the array is smaller, segments
* are added until the array is larger then the specified length.
*/
public void ensureCapacity(long length)
{
array.ensureCapacity(length);
}
private void updateRetainedSize(Slice oldValue, Slice newValue)
{
if (oldValue != null) {
int baseReferenceCount = trackedSlices.decrementAndGet(oldValue.byteArray());
int sliceReferenceCount = trackedSlices.decrementAndGet(oldValue);
if (baseReferenceCount == 0) {
// it is the last referenced base
sizeOfSlices -= oldValue.getRetainedSize();
}
else if (sliceReferenceCount == 0) {
// it is the last referenced slice
sizeOfSlices -= SLICE_INSTANCE_SIZE;
}
}
if (newValue != null) {
int baseReferenceCount = trackedSlices.incrementAndGet(newValue.byteArray());
int sliceReferenceCount = trackedSlices.incrementAndGet(newValue);
if (baseReferenceCount == 1) {
// it is the first referenced base
sizeOfSlices += newValue.getRetainedSize();
}
else if (sliceReferenceCount == 1) {
// it is the first referenced slice
sizeOfSlices += SLICE_INSTANCE_SIZE;
}
}
}
}