content: /*
   * Copyright 2002-2019 Drew Noakes and contributors
   *
   *    Licensed 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
   *
   *        https://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.
   *
   * More information about this project is available at:
   *
   *    https://drewnoakes.com/code/exif/
   *    https://github.com/drewnoakes/metadata-extractor
   */
  
  package com.drew.lang;
  
  import com.drew.lang.annotations.NotNull;
  
  import java.io.IOException;
  
  /**
   * Provides methods to read specific values from a byte array, with a consistent, checked exception structure for
   * issues.
   * <p>
   * By default, the reader operates with Motorola byte order (big endianness).  This can be changed by calling
   * <code>setMotorolaByteOrder(boolean)</code>.
   *
   * @author Drew Noakes https://drewnoakes.com
   * */
  public class ByteArrayReader extends RandomAccessReader
  {
      @NotNull
      private final byte[] _buffer;
      private final int _baseOffset;
  
      @SuppressWarnings({ "ConstantConditions" })
      @com.drew.lang.annotations.SuppressWarnings(value = "EI_EXPOSE_REP2", justification = "Design intent")
      public ByteArrayReader(@NotNull byte[] buffer)
      {
          this(buffer, 0);
      }
  
      @SuppressWarnings({ "ConstantConditions" })
      @com.drew.lang.annotations.SuppressWarnings(value = "EI_EXPOSE_REP2", justification = "Design intent")
      public ByteArrayReader(@NotNull byte[] buffer, int baseOffset)
      {
          if (buffer == null)
              throw new NullPointerException();
          if (baseOffset < 0)
              throw new IllegalArgumentException("Must be zero or greater");
  
          _buffer = buffer;
          _baseOffset = baseOffset;
      }
  
      @Override
      public int toUnshiftedOffset(int localOffset)
      {
          return localOffset + _baseOffset;
      }
  
      @Override
      public long getLength()
      {
          return _buffer.length - _baseOffset;
      }
  
      @Override
      public byte getByte(int index) throws IOException
      {
          validateIndex(index, 1);
          return _buffer[index + _baseOffset];
      }
  
      @Override
      protected void validateIndex(int index, int bytesRequested) throws IOException
      {
          if (!isValidIndex(index, bytesRequested))
              throw new BufferBoundsException(toUnshiftedOffset(index), bytesRequested, _buffer.length);
      }
  
      @Override
      protected boolean isValidIndex(int index, int bytesRequested) throws IOException
      {
          return bytesRequested >= 0
              && index >= 0
              && (long)index + (long)bytesRequested - 1L < getLength();
      }
  
      @Override
      @NotNull
      public byte[] getBytes(int index, int count) throws IOException
      {
          validateIndex(index, count);
  
          byte[] bytes = new byte[count];
          System.arraycopy(_buffer, index + _baseOffset, bytes, 0, count);
          return bytes;
      }
  }
  