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 static org.testng.Assert.assertFalse;
  import static org.testng.Assert.assertTrue;
  
  import java.nio.ByteBuffer;
  import java.nio.ByteOrder;
  import java.util.concurrent.ThreadLocalRandom;
  
  import org.apache.datasketches.memory.Memory;
  import org.apache.datasketches.memory.WritableBuffer;
  import org.apache.datasketches.memory.WritableMemory;
  import org.testng.annotations.Test;
  
  public class WritableMemoryTest {
  
    @Test
    public void wrapBigEndian() {
      ByteBuffer bb = ByteBuffer.allocate(64); //big endian
      WritableMemory wmem = WritableMemory.writableWrap(bb);
      assertEquals(wmem.getByteOrder(), ByteOrder.BIG_ENDIAN);
      wmem = WritableMemory.writableWrap(bb, ByteOrder.nativeOrder());
      assertEquals(wmem.getByteOrder(), ByteOrder.LITTLE_ENDIAN);
    }
  
    @Test
    public void wrapBigEndianAsLittle() {
      ByteBuffer bb = ByteBuffer.allocate(64);
      bb.putChar(0, (char)1); //as NNO
      WritableMemory wmem = WritableMemory.writableWrap(bb, ByteOrder.LITTLE_ENDIAN, null);
      assertEquals(wmem.getChar(0), 256);
    }
  
    @Test
    public void allocateWithByteOrder() {
      WritableMemory wmem = WritableMemory.allocate(64, ByteOrder.BIG_ENDIAN);
      assertEquals(wmem.getByteOrder(), ByteOrder.BIG_ENDIAN);
      wmem = WritableMemory.allocate(64, ByteOrder.LITTLE_ENDIAN);
      assertEquals(wmem.getByteOrder(), ByteOrder.LITTLE_ENDIAN);
      wmem = WritableMemory.writableWrap(new byte[64], 32, 32, ByteOrder.BIG_ENDIAN);
      assertEquals(wmem.getByteOrder(), ByteOrder.BIG_ENDIAN);
    }
  
    @Test
    public void checkGetArray() {
      byte[] byteArr = new byte[64];
      WritableMemory wmem = WritableMemory.writableWrap(byteArr);
      assertTrue(((BaseWritableMemoryImpl) wmem).getArray() == byteArr);
      WritableBuffer wbuf = wmem.asWritableBuffer();
      assertTrue(((BaseWritableBufferImpl)wbuf).getArray() == byteArr);
    }
  
    @Test(expectedExceptions = IllegalArgumentException.class)
    public void checkSelfArrayCopy() {
      byte[] srcAndDst = new byte[128];
      WritableMemory wmem = WritableMemory.writableWrap(srcAndDst);
      wmem.getByteArray(0, srcAndDst, 64, 64);  //non-overlapping
    }
  
    @Test
    public void checkEquals() {
      int len = 7;
      WritableMemory wmem1 = WritableMemory.allocate(len);
      //@SuppressWarnings({"EqualsWithItself", "SelfEquals"}) //unsupported
      //SelfEquals for Plexus, EqualsWithItself for IntelliJ
      //boolean eq1 = wmem1.equalTo(wmem1); //strict profile complains
      //assertTrue(eq1);
  
      WritableMemory wmem2 = WritableMemory.allocate(len + 1);
      assertFalse(wmem1.equalTo(wmem2));
  
      WritableMemory reg1 = wmem1.writableRegion(0, wmem1.getCapacity());
      assertTrue(wmem1.equalTo(reg1));
  
      wmem2 = WritableMemory.allocate(len);
      for (int i = 0; i < len; i++) {
        wmem1.putByte(i, (byte) i);
        wmem2.putByte(i, (byte) i);
      }
      assertTrue(wmem1.equalTo(wmem2));
      assertTrue(wmem1.equalTo(0, wmem1, 0, len));
  
      reg1 = wmem1.writableRegion(0, wmem1.getCapacity());
      assertTrue(wmem1.equalTo(0, reg1, 0, len));
  
      len = 24;
      wmem1 = WritableMemory.allocate(len);
      wmem2 = WritableMemory.allocate(len);
      for (int i = 0; i < len; i++) {
        wmem1.putByte(i, (byte) i);
        wmem2.putByte(i, (byte) i);
      }
      assertTrue(wmem1.equalTo(0, wmem2, 0, len - 1));
      assertTrue(wmem1.equalTo(0, wmem2, 0, len));
      wmem2.putByte(0, (byte) 10);
      assertFalse(wmem1.equalTo(0, wmem2, 0, len));
      wmem2.putByte(0, (byte) 0);
      wmem2.putByte(len - 2, (byte) 0);
      assertFalse(wmem1.equalTo(0, wmem2, 0, len - 1));
    }
  
    @Test
    public void checkEquals2() {
      int len = 23;
      WritableMemory wmem1 = WritableMemory.allocate(len);
      assertFalse(wmem1.equalTo(null));
      //@SuppressWarnings({"EqualsWithItself", "SelfEquals"}) //unsupported
      //SelfEquals for Plexus, EqualsWithItself for IntelliJ
      //boolean eq1 = wmem1.equalTo(wmem1); //strict profile complains
      //assertTrue(eq1);
  
      WritableMemory wmem2 = WritableMemory.allocate(len + 1);
      assertFalse(wmem1.equalTo(wmem2));
  
      for (int i = 0; i < len; i++) {
        wmem1.putByte(i, (byte) i);
        wmem2.putByte(i, (byte) i);
      }
      assertTrue(wmem1.equalTo(0, wmem2, 0, len));
      assertTrue(wmem1.equalTo(1, wmem2, 1, len - 1));
    }
  
    @Test
    public void checkLargeEquals() {
      // Size bigger than UNSAFE_COPY_MEMORY_THRESHOLD; size with "reminder" = 7, to test several
      // traits of the implementation
      final int thresh = Util.UNSAFE_COPY_THRESHOLD_BYTES;
      byte[] bytes1 = new byte[(thresh * 2) + 7];
      ThreadLocalRandom.current().nextBytes(bytes1);
      byte[] bytes2 = bytes1.clone();
      Memory mem1 = Memory.wrap(bytes1);
      Memory mem2 = Memory.wrap(bytes2);
      assertTrue(mem1.equalTo(mem2));
  
      bytes2[thresh + 10] = (byte) (bytes1[thresh + 10] + 1);
      assertFalse(mem1.equalTo(mem2));
  
      bytes2[thresh + 10] = bytes1[thresh + 10];
      bytes2[(thresh * 2) + 3] = (byte) (bytes1[(thresh * 2) + 3] + 1);
      assertFalse(mem1.equalTo(mem2));
    }
  
    @Test
    public void checkWrapWithBO() {
      WritableMemory wmem = WritableMemory.writableWrap(new byte[0], ByteOrder.BIG_ENDIAN);
      boolean nativeBO = wmem.getByteOrder() == ByteOrder.nativeOrder();
      assertFalse(nativeBO);
      println("" + nativeBO);
      wmem = WritableMemory.writableWrap(new byte[8], ByteOrder.BIG_ENDIAN);
      nativeBO = wmem.getByteOrder() == ByteOrder.nativeOrder();
      assertFalse(nativeBO);
      println("" + nativeBO);
    }
  
    @Test
    @SuppressWarnings("unused")
    public void checkOwnerClientCase() {
      WritableMemory owner = WritableMemory.allocate(64);
      Memory client1 = owner; //Client1 cannot write (no API)
      owner.putInt(0, 1); //But owner can write
      ((WritableMemory)client1).putInt(0, 2); //Client1 can write, but with explicit effort.
      Memory client2 = owner.region(0, owner.getCapacity()); //client2 cannot write (no API)
      owner.putInt(0, 3); //But Owner should be able to write
    }
  
    @Test
    public void printlnTest() {
      println("PRINTING: " + this.getClass().getName());
    }
  
    /**
     * @param s value to print
     */
    static void println(final String s) {
      //System.out.println(s);
    }
  
  }
  