spark-gpu-master/core/src/main/java/org/apache/spark/shuffle/sort/ShuffleSortDataFormat.java
/*
 * 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.spark.shuffle.sort;

import org.apache.spark.unsafe.Platform;
import org.apache.spark.unsafe.array.LongArray;
import org.apache.spark.unsafe.memory.MemoryBlock;
import org.apache.spark.util.collection.SortDataFormat;

final class ShuffleSortDataFormat extends SortDataFormat<PackedRecordPointer, LongArray> {

  public static final ShuffleSortDataFormat INSTANCE = new ShuffleSortDataFormat();

  private ShuffleSortDataFormat() { }

  @Override
  public PackedRecordPointer getKey(LongArray data, int pos) {
    // Since we re-use keys, this method shouldn't be called.
    throw new UnsupportedOperationException();
  }

  @Override
  public PackedRecordPointer newKey() {
    return new PackedRecordPointer();
  }

  @Override
  public PackedRecordPointer getKey(LongArray data, int pos, PackedRecordPointer reuse) {
    reuse.set(data.get(pos));
    return reuse;
  }

  @Override
  public void swap(LongArray data, int pos0, int pos1) {
    final long temp = data.get(pos0);
    data.set(pos0, data.get(pos1));
    data.set(pos1, temp);
  }

  @Override
  public void copyElement(LongArray src, int srcPos, LongArray dst, int dstPos) {
    dst.set(dstPos, src.get(srcPos));
  }

  @Override
  public void copyRange(LongArray src, int srcPos, LongArray dst, int dstPos, int length) {
    Platform.copyMemory(
      src.getBaseObject(),
      src.getBaseOffset() + srcPos * 8,
      dst.getBaseObject(),
      dst.getBaseOffset() + dstPos * 8,
      length * 8
    );
  }

  @Override
  public LongArray allocate(int length) {
    // This buffer is used temporary (usually small), so it's fine to allocated from JVM heap.
    return new LongArray(MemoryBlock.fromLongArray(new long[length]));
  }

}
