//
   //  ========================================================================
   //  Copyright (c) 1995-2013 Mort Bay Consulting Pty. Ltd.
   //  ------------------------------------------------------------------------
   //  All rights reserved. This program and the accompanying materials
   //  are made available under the terms of the Eclipse Public License v1.0
   //  and Apache License v2.0 which accompanies this distribution.
   //
   //      The Eclipse Public License is available at
  //      http://www.eclipse.org/legal/epl-v10.html
  //
  //      The Apache License v2.0 is available at
  //      http://www.opensource.org/licenses/apache2.0.php
  //
  //  You may elect to redistribute this code under either of these licenses.
  //  ========================================================================
  //
  
  package org.eclipse.jetty.websocket.common.extensions.compress;
  
  import java.nio.ByteBuffer;
  import java.util.ArrayList;
  import java.util.List;
  
  import org.eclipse.jetty.io.ByteBufferPool;
  import org.eclipse.jetty.util.BufferUtil;
  import org.eclipse.jetty.websocket.api.MessageTooLargeException;
  
  public class ByteAccumulator
  {
      private static class Buf
      {
          public Buf(byte[] buffer, int offset, int length)
          {
              this.buffer = buffer;
              this.offset = offset;
              this.length = length;
          }
  
          byte[] buffer;
          int offset;
          int length;
      }
  
      private final int maxSize;
      private int length = 0;
      private List<Buf> buffers;
  
      public ByteAccumulator(int maxOverallBufferSize)
      {
          this.maxSize = maxOverallBufferSize;
          this.buffers = new ArrayList<>();
      }
  
      public void addBuffer(byte buf[], int offset, int length)
      {
          if (this.length + length > maxSize)
          {
              throw new MessageTooLargeException("Frame is too large");
          }
          buffers.add(new Buf(buf,offset,length));
          this.length += length;
      }
  
      public int getLength()
      {
          return length;
      }
  
      public ByteBuffer getByteBuffer(ByteBufferPool pool)
      {
          ByteBuffer ret = pool.acquire(length,false);
          BufferUtil.clearToFill(ret);
  
          for (Buf buf : buffers)
          {
              ret.put(buf.buffer, buf.offset, buf.length);
          }
  
          BufferUtil.flipToFlush(ret,0);
          return ret;
      }
  }