content: /*
   * Copyright (c) 2022, Oracle and/or its affiliates. All rights reserved.
   * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   *
   * This code is free software; you can redistribute it and/or modify it
   * under the terms of the GNU General Public License version 2 only, as
   * published by the Free Software Foundation.  Oracle designates this
   * particular file as subject to the "Classpath" exception as provided
   * by Oracle in the LICENSE file that accompanied this code.
   *
   * This code is distributed in the hope that it will be useful, but WITHOUT
   * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
   * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
   * version 2 for more details (a copy is included in the LICENSE file that
   * accompanied this code).
   *
   * You should have received a copy of the GNU General Public License version
   * 2 along with this work; if not, write to the Free Software Foundation,
   * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
   *
   * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
   * or visit www.oracle.com if you need additional information or have any
   * questions.
   */
  
  package javac.internal.jimage;
  
  import java.nio.ByteBuffer;
  import java.nio.ByteOrder;
  import java.util.Arrays;
  import java.util.Objects;
  
  /**
   * @implNote This class needs to maintain JDK 8 source compatibility.
   *
   * It is used internally in the JDK to implement jimage/jrtfs access,
   * but also compiled and delivered as part of the jrtfs.jar to support access
   * to the jimage file provided by the shipped JDK by tools running on JDK 8.
   */
  public class ImageStream {
      private ByteBuffer buffer;
  
      public ImageStream() {
          this(1024, ByteOrder.nativeOrder());
      }
  
      public ImageStream(int size) {
          this(size, ByteOrder.nativeOrder());
      }
  
      public ImageStream(byte[] bytes) {
         this(bytes, ByteOrder.nativeOrder());
      }
  
      public ImageStream(ByteOrder byteOrder) {
          this(1024, byteOrder);
      }
  
      public ImageStream(int size, ByteOrder byteOrder) {
          buffer = ByteBuffer.allocate(size);
          buffer.order(Objects.requireNonNull(byteOrder));
      }
  
      public ImageStream(byte[] bytes, ByteOrder byteOrder) {
          buffer = ByteBuffer.wrap(Objects.requireNonNull(bytes));
          buffer.order(Objects.requireNonNull(byteOrder));
      }
  
      public ImageStream(ByteBuffer buffer) {
          this.buffer = Objects.requireNonNull(buffer);
      }
  
      public ImageStream align(int alignment) {
          int padding = (getSize() - 1) & ((1 << alignment) - 1);
  
          for (int i = 0; i < padding; i++) {
              put((byte)0);
          }
  
          return this;
      }
  
      public void ensure(int needs) {
          if (needs < 0) {
              throw new IndexOutOfBoundsException("Bad value: " + needs);
          }
  
          if (needs > buffer.remaining()) {
              byte[] bytes = buffer.array();
              ByteOrder byteOrder = buffer.order();
              int position = buffer.position();
              int newSize = needs <= bytes.length ? bytes.length << 1 : position + needs;
              buffer = ByteBuffer.allocate(newSize);
              buffer.order(byteOrder);
              buffer.put(bytes, 0, position);
          }
      }
  
      public boolean hasByte() {
          return buffer.remaining() != 0;
      }
  
      public boolean hasBytes(int needs) {
          return needs <= buffer.remaining();
      }
  
      public void skip(int n) {
          if (n < 0) {
              throw new IndexOutOfBoundsException("skip value = " + n);
          }
  
          buffer.position(buffer.position() + n);
      }
  
      public int get() {
          return buffer.get() & 0xFF;
      }
  
      public void get(byte bytes[], int offset, int size) {
          buffer.get(bytes, offset, size);
      }
  
      public int getShort() {
          return buffer.getShort();
      }
  
      public int getInt() {
          return buffer.getInt();
      }
  
      public long getLong() {
          return buffer.getLong();
      }
  
      public ImageStream put(byte byt) {
          ensure(1);
          buffer.put(byt);
  
          return this;
      }
  
      public ImageStream put(int byt) {
          return put((byte)byt);
      }
  
      public ImageStream put(byte bytes[], int offset, int size) {
          ensure(size);
          buffer.put(bytes, offset, size);
  
          return this;
      }
  
      public ImageStream put(ImageStream stream) {
          put(stream.buffer.array(), 0, stream.buffer.position());
  
          return this;
      }
  
      public ImageStream putShort(short value) {
          ensure(2);
          buffer.putShort(value);
  
          return this;
      }
  
      public ImageStream putShort(int value) {
          return putShort((short)value);
      }
  
      public ImageStream putInt(int value) {
          ensure(4);
          buffer.putInt(value);
  
          return this;
      }
  
      public ImageStream putLong(long value) {
          ensure(8);
          buffer.putLong(value);
  
          return this;
      }
  
      public ByteBuffer getBuffer() {
          return buffer;
      }
  
      public int getPosition() {
          return buffer.position();
      }
  
      public int getSize() {
          return buffer.position();
      }
  
      public byte[] getBytes() {
          return buffer.array();
      }
  
      public void setPosition(int offset) {
          buffer.position(offset);
      }
  
      public byte[] toArray() {
          return Arrays.copyOf(buffer.array(), buffer.position());
      }
  }
  