content: /*
   * 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.unsafe.memory;
  
  import javax.annotation.Nullable;
  
  import org.apache.spark.unsafe.Platform;
  
  /**
   * A consecutive block of memory, starting at a {@link MemoryLocation} with a fixed size.
   */
  public class MemoryBlock extends MemoryLocation {
  
    private final long length;
  
    /**
     * Optional page number; used when this MemoryBlock represents a page allocated by a
     * TaskMemoryManager. This field is public so that it can be modified by the TaskMemoryManager,
     * which lives in a different package.
     */
    public int pageNumber = -1;
  
    public MemoryBlock(@Nullable Object obj, long offset, long length) {
      super(obj, offset);
      this.length = length;
    }
  
    /**
     * Returns the size of the memory block.
     */
    public long size() {
      return length;
    }
  
    /**
     * Creates a memory block pointing to the memory used by the long array.
     */
    public static MemoryBlock fromLongArray(final long[] array) {
      return new MemoryBlock(array, Platform.LONG_ARRAY_OFFSET, array.length * 8L);
    }
  
    /**
     * Fills the memory block with the specified byte value.
     */
    public void fill(byte value) {
      Platform.setMemory(obj, offset, length, value);
    }
  }
  