code: /*
   * 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.memory.internal;
  
  import static org.testng.Assert.assertEquals;
  
  import org.apache.datasketches.memory.Memory;
  import org.apache.datasketches.memory.WritableMemory;
  import org.testng.annotations.Test;
  
  /**
   * @author Lee Rhodes
   */
  public class CopyMemoryOverlapTest {
  
    @Test
    public void checkOverlapUsingMemory() throws Exception {
      long copyLongs = 1 << 20;
      double overlap = 0.5;
      long start_mS = System.currentTimeMillis();
  
      copyUsingDirectMemory(copyLongs, overlap, true);
      long end1_mS = System.currentTimeMillis();
  
      copyUsingDirectMemory(copyLongs, overlap, false);
      long end2_mS = System.currentTimeMillis();
  
      println("CopyUp Time Sec: " + ((end1_mS - start_mS) / 1000.0));
      println("CopyDn Time Sec: " + ((end2_mS - end1_mS) / 1000.0));
    }
  
    @Test
    public void checkOverlapUsingRegions() throws Exception {
      long copyLongs = 1 << 20;
      double overlap = 0.5;
      long start_mS = System.currentTimeMillis();
  
      copyUsingDirectRegions(copyLongs, overlap, true);
      long end1_mS = System.currentTimeMillis();
  
      copyUsingDirectRegions(copyLongs, overlap, false);
      long end2_mS = System.currentTimeMillis();
  
      println("CopyUp Time Sec: " + ((end1_mS - start_mS) / 1000.0));
      println("CopyDn Time Sec: " + ((end2_mS - end1_mS) / 1000.0));
    }
  
    private static final void copyUsingDirectMemory(long copyLongs, double overlap, boolean copyUp) throws Exception {
      println("Copy Using Direct Memory");
      long overlapLongs = (long) (overlap * copyLongs);
      long backingLongs = (2 * copyLongs) - overlapLongs;
  
      long fromOffsetLongs;
      long toOffsetLongs;
      //long deltaLongs;
  
      if (copyUp) {
        fromOffsetLongs = 0;
        toOffsetLongs = copyLongs - overlapLongs;
        //deltaLongs = toOffsetLongs - fromOffsetLongs;
      } else {
        fromOffsetLongs = copyLongs - overlapLongs;
        toOffsetLongs = 0;
        //deltaLongs = toOffsetLongs - fromOffsetLongs;
      }
  
      long backingBytes = backingLongs << 3;
      long copyBytes = copyLongs << 3;
      long fromOffsetBytes = fromOffsetLongs << 3;
      long toOffsetBytes = toOffsetLongs << 3;
      //long deltaBytes = deltaLongs << 3;
      println("Copy longs   : " + copyLongs    + "\t bytes: " + copyBytes);
      println("Overlap      : " + (overlap * 100.0) + "%");
      println("CopyUp       : " + copyUp);
      println("Backing longs: " + backingLongs + "\t bytes: " + backingBytes);
  
      try (WritableMemory backingMem = WritableMemory.allocateDirect(backingBytes)) {
        fill(backingMem); //fill mem with 0 thru copyLongs -1
        //listMem(backingMem, "Original");
        backingMem.copyTo(fromOffsetBytes, backingMem, toOffsetBytes, copyBytes);
        //listMem(backingMem, "After");
        checkMemLongs(backingMem, fromOffsetLongs, toOffsetLongs, copyLongs);
      }
      println("");
    }
  
    private static final void copyUsingDirectRegions(long copyLongs, double overlap, boolean copyUp) throws Exception {
      println("Copy Using Direct Memory");
      long overlapLongs = (long) (overlap * copyLongs);
      long backingLongs = (2 * copyLongs) - overlapLongs;
  
      long fromOffsetLongs;
      long toOffsetLongs;
      //long deltaLongs;
  
      if (copyUp) {
        fromOffsetLongs = 0;
        toOffsetLongs = copyLongs - overlapLongs;
        //deltaLongs = toOffsetLongs - fromOffsetLongs;
      } else {
        fromOffsetLongs = copyLongs - overlapLongs;
        toOffsetLongs = 0;
        //deltaLongs = toOffsetLongs - fromOffsetLongs;
      }
  
      long backingBytes = backingLongs << 3;
      long copyBytes = copyLongs << 3;
      long fromOffsetBytes = fromOffsetLongs << 3;
      long toOffsetBytes = toOffsetLongs << 3;
      //long deltaBytes = deltaLongs << 3;
      println("Copy longs   : " + copyLongs    + "\t bytes: " + copyBytes);
      println("Overlap      : " + (overlap * 100.0) + "%");
      println("CopyUp       : " + copyUp);
      println("Backing longs: " + backingLongs + "\t bytes: " + backingBytes);
  
      try (WritableMemory backingMem = WritableMemory.allocateDirect(backingBytes)) {
        fill(backingMem); //fill mem with 0 thru copyLongs -1
        //listMem(backingMem, "Original");
        WritableMemory reg1 = backingMem.writableRegion(fromOffsetBytes, copyBytes);
        WritableMemory reg2 = backingMem.writableRegion(toOffsetBytes, copyBytes);
  
        reg1.copyTo(0, reg2, 0, copyBytes);
        //listMem(backingMem, "After");
        checkMemLongs(reg2, fromOffsetLongs, 0, copyLongs);
      }
      println("");
    }
  
    private static final void fill(WritableMemory wmem) {
      long longs = wmem.getCapacity() >>> 3;
      for (long i = 0; i < longs; i++) { wmem.putLong(i << 3, i); } //fill with 0 .. (longs - 1)
      //checkMemLongs(wmem, 0L, 0L, longs);
    }
  
    private static final void checkMemLongs(Memory mem, long fromOffsetLongs, long toOffsetLongs, long copyLongs) {
      for (long i = 0; i < copyLongs; i++) {
        long memVal = mem.getLong((toOffsetLongs + i) << 3);
        assertEquals(memVal, fromOffsetLongs + i);
      }
    }
  
    @SuppressWarnings("unused")
    private static final void listMem(Memory mem, String comment) {
      println(comment);
      println("Idx\tValue");
      long longs = mem.getCapacity() >>> 3;
      for (long i = 0; i < longs; i++) {
        println(i + "\t" + mem.getLong(i << 3));
      }
    }
  
    @Test
    public void printlnTest() {
      println("PRINTING: " + this.getClass().getName());
    }
  
    /**
     * @param s value to print
     */
    static void println(String s) {
      //System.out.println(s); //disable here
    }
  }
  