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.apache.datasketches.memory.internal.Util.UNSAFE_COPY_THRESHOLD_BYTES;
  import static org.testng.Assert.assertEquals;
  
  import java.util.concurrent.ThreadLocalRandom;
  
  import org.apache.datasketches.memory.Memory;
  import org.apache.datasketches.memory.WritableMemory;
  import org.testng.Assert;
  import org.testng.annotations.Test;
  
  public class CopyMemoryTest {
  
    @Test
    public void heapWSource() {
      int k1 = 1 << 20; //longs
      int k2 = 2 * k1;
      WritableMemory srcMem = genMem(k1, false); //!empty
      //println(srcMem.toHexString("src: ", 0, k1 << 3));
      WritableMemory dstMem = genMem(k2, true);
      srcMem.copyTo(0, dstMem, k1 << 3, k1 << 3);
      //println(dstMem.toHexString("dst: ", 0, k2 << 3));
      check(dstMem, k1, k1, 1);
    }
  
    @Test
    public void heapROSource() {
      int k1 = 1 << 20; //longs
      int k2 = 2 * k1;
      Memory srcMem = genMem(k1, false); //!empty
      WritableMemory dstMem = genMem(k2, true);
      srcMem.copyTo(0, dstMem, k1 << 3, k1 << 3);
      check(dstMem, k1, k1, 1);
    }
  
    @Test
    public void directWSource() throws Exception {
      int k1 = 1 << 20; //longs
      int k2 = 2 * k1;
      try (WritableMemory srcMem = genWRH(k1, false)) {
        WritableMemory dstMem = genMem(k2, true);
        srcMem.copyTo(0, dstMem, k1 << 3, k1 << 3);
        check(dstMem, k1, k1, 1);
      }
    }
  
    @Test
    public void directROSource() throws Exception {
      int k1 = 1 << 20; //longs
      int k2 = 2 * k1;
      try (Memory srcMem = genWRH(k1, false)) {
        WritableMemory dstMem = genMem(k2, true);
        srcMem.copyTo(0, dstMem, k1 << 3, k1 << 3);
        check(dstMem, k1, k1, 1);
      }
    }
  
    @Test
    public void heapWSrcRegion() {
      int k1 = 1 << 20; //longs
      //gen baseMem of k1 longs w data
      WritableMemory baseMem = genMem(k1, false); //!empty
      //gen src region of k1/2 longs, off= k1/2
      WritableMemory srcReg = baseMem.writableRegion((k1 / 2) << 3, (k1 / 2) << 3);
      WritableMemory dstMem = genMem(2 * k1, true); //empty
      srcReg.copyTo(0, dstMem, k1 << 3, (k1 / 2) << 3);
      //println(dstMem.toHexString("dstMem: ", k1 << 3, (k1/2) << 3));
      check(dstMem, k1, k1 / 2, (k1 / 2) + 1);
    }
  
    @Test
    public void heapROSrcRegion() {
      int k1 = 1 << 20; //longs
      //gen baseMem of k1 longs w data
      WritableMemory baseMem = genMem(k1, false); //!empty
      //gen src region of k1/2 longs, off= k1/2
      Memory srcReg = baseMem.region((k1 / 2) << 3, (k1 / 2) << 3);
      WritableMemory dstMem = genMem(2 * k1, true); //empty
      srcReg.copyTo(0, dstMem, k1 << 3, (k1 / 2) << 3);
      check(dstMem, k1, k1 / 2, (k1 / 2) + 1);
    }
  
    @Test
    public void directROSrcRegion() throws Exception {
      int k1 = 1 << 20; //longs
      //gen baseMem of k1 longs w data, direct
      try (Memory baseMem = genWRH(k1, false)) {
        //gen src region of k1/2 longs, off= k1/2
        Memory srcReg = baseMem.region((k1 / 2) << 3, (k1 / 2) << 3);
        WritableMemory dstMem = genMem(2 * k1, true); //empty
        srcReg.copyTo(0, dstMem, k1 << 3, (k1 / 2) << 3);
        check(dstMem, k1, k1 / 2, (k1 / 2) + 1);
      }
    }
  
    @Test
    public void testOverlappingCopyLeftToRight() {
      byte[] bytes = new byte[((UNSAFE_COPY_THRESHOLD_BYTES * 5) / 2) + 1];
      ThreadLocalRandom.current().nextBytes(bytes);
      byte[] referenceBytes = bytes.clone();
      Memory referenceMem = Memory.wrap(referenceBytes);
      WritableMemory mem = WritableMemory.writableWrap(bytes);
      long copyLen = UNSAFE_COPY_THRESHOLD_BYTES * 2;
      mem.copyTo(0, mem, UNSAFE_COPY_THRESHOLD_BYTES / 2, copyLen);
      Assert.assertEquals(0, mem.compareTo(UNSAFE_COPY_THRESHOLD_BYTES / 2, copyLen, referenceMem, 0,
          copyLen));
    }
  
    @Test
    public void testOverlappingCopyRightToLeft() {
      byte[] bytes = new byte[((UNSAFE_COPY_THRESHOLD_BYTES * 5) / 2) + 1];
      ThreadLocalRandom.current().nextBytes(bytes);
      byte[] referenceBytes = bytes.clone();
      Memory referenceMem = Memory.wrap(referenceBytes);
      WritableMemory mem = WritableMemory.writableWrap(bytes);
      long copyLen = UNSAFE_COPY_THRESHOLD_BYTES * 2;
      mem.copyTo(UNSAFE_COPY_THRESHOLD_BYTES / 2, mem, 0, copyLen);
      Assert.assertEquals(0, mem.compareTo(0, copyLen, referenceMem, UNSAFE_COPY_THRESHOLD_BYTES / 2,
          copyLen));
    }
  
    private static void check(Memory mem, int offsetLongs, int lengthLongs, int startValue) {
      int offBytes = offsetLongs << 3;
      for (long i = 0; i < lengthLongs; i++) {
        assertEquals(mem.getLong(offBytes + (i << 3)), i + startValue);
      }
    }
  
    private static WritableMemory genWRH(int longs, boolean empty) {
      WritableMemory mem = WritableMemory.allocateDirect(longs << 3);
      if (empty) {
        mem.clear();
      } else {
        for (int i = 0; i < longs; i++) { mem.putLong(i << 3, i + 1); }
      }
      return mem;
    }
  
    private static WritableMemory genMem(int longs, boolean empty) {
      WritableMemory mem = WritableMemory.allocate(longs << 3);
      if (!empty) {
        for (int i = 0; i < longs; i++) { mem.putLong(i << 3, i + 1); }
      }
      return mem;
    }
  
    @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
    }
  }
  