/*
    * Copyright 2012 The Netty Project
    *
    * The Netty Project 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.jboss.netty.buffer;
  
  import java.io.IOException;
  import java.io.InputStream;
  import java.io.OutputStream;
  import java.nio.ByteBuffer;
  import java.nio.ByteOrder;
  import java.nio.channels.GatheringByteChannel;
  import java.nio.channels.ScatteringByteChannel;
  
  
  /**
   * A dynamic capacity buffer which increases its capacity as needed.  It is
   * recommended to use {@link ChannelBuffers#dynamicBuffer(int)} instead of
   * calling the constructor explicitly.
   */
  public class DynamicChannelBuffer extends AbstractChannelBuffer {
  
      private final ChannelBufferFactory factory;
      private final ByteOrder endianness;
      private ChannelBuffer buffer;
  
      public DynamicChannelBuffer(int estimatedLength) {
          this(ByteOrder.BIG_ENDIAN, estimatedLength);
      }
  
      public DynamicChannelBuffer(ByteOrder endianness, int estimatedLength) {
          this(endianness, estimatedLength, HeapChannelBufferFactory.getInstance(endianness));
      }
  
      public DynamicChannelBuffer(ByteOrder endianness, int estimatedLength, ChannelBufferFactory factory) {
          if (estimatedLength < 0) {
              throw new IllegalArgumentException("estimatedLength: " + estimatedLength);
          }
          if (endianness == null) {
              throw new NullPointerException("endianness");
          }
          if (factory == null) {
              throw new NullPointerException("factory");
          }
          this.factory = factory;
          this.endianness = endianness;
          buffer = factory.getBuffer(order(), estimatedLength);
      }
  
      @Override
      public void ensureWritableBytes(int minWritableBytes) {
          if (minWritableBytes <= writableBytes()) {
              return;
          }
  
          int newCapacity;
          if (capacity() == 0) {
              newCapacity = 1;
          } else {
              newCapacity = capacity();
          }
          int minNewCapacity = writerIndex() + minWritableBytes;
          while (newCapacity < minNewCapacity) {
              newCapacity <<= 1;
  
              // Check if we exceeded the maximum size of 2gb if this is the case then
              // newCapacity == 0
              //
              // https://github.com/netty/netty/issues/258
              if (newCapacity == 0) {
                  throw new IllegalStateException("Maximum size of 2gb exceeded");
              }
          }
  
          ChannelBuffer newBuffer = factory().getBuffer(order(), newCapacity);
          newBuffer.writeBytes(buffer, 0, writerIndex());
          buffer = newBuffer;
      }
  
      public ChannelBufferFactory factory() {
          return factory;
      }
  
      public ByteOrder order() {
          return endianness;
      }
  
      public boolean isDirect() {
         return buffer.isDirect();
     }
 
     public int capacity() {
         return buffer.capacity();
     }
 
     public boolean hasArray() {
         return buffer.hasArray();
     }
 
     public byte[] array() {
         return buffer.array();
     }
 
     public int arrayOffset() {
         return buffer.arrayOffset();
     }
 
     public byte getByte(int index) {
         return buffer.getByte(index);
     }
 
     public short getShort(int index) {
         return buffer.getShort(index);
     }
 
     public int getUnsignedMedium(int index) {
         return buffer.getUnsignedMedium(index);
     }
 
     public int getInt(int index) {
         return buffer.getInt(index);
     }
 
     public long getLong(int index) {
         return buffer.getLong(index);
     }
 
     public void getBytes(int index, byte[] dst, int dstIndex, int length) {
         buffer.getBytes(index, dst, dstIndex, length);
     }
 
     public void getBytes(int index, ChannelBuffer dst, int dstIndex, int length) {
         buffer.getBytes(index, dst, dstIndex, length);
     }
 
     public void getBytes(int index, ByteBuffer dst) {
         buffer.getBytes(index, dst);
     }
 
     public int getBytes(int index, GatheringByteChannel out, int length)
             throws IOException {
         return buffer.getBytes(index, out, length);
     }
 
     public void getBytes(int index, OutputStream out, int length)
             throws IOException {
         buffer.getBytes(index, out, length);
     }
 
     public void setByte(int index, int value) {
         buffer.setByte(index, value);
     }
 
     public void setShort(int index, int value) {
         buffer.setShort(index, value);
     }
 
     public void setMedium(int index, int value) {
         buffer.setMedium(index, value);
     }
 
     public void setInt(int index, int value) {
         buffer.setInt(index, value);
     }
 
     public void setLong(int index, long value) {
         buffer.setLong(index, value);
     }
 
     public void setBytes(int index, byte[] src, int srcIndex, int length) {
         buffer.setBytes(index, src, srcIndex, length);
     }
 
     public void setBytes(int index, ChannelBuffer src, int srcIndex, int length) {
         buffer.setBytes(index, src, srcIndex, length);
     }
 
     public void setBytes(int index, ByteBuffer src) {
         buffer.setBytes(index, src);
     }
 
     public int setBytes(int index, InputStream in, int length)
             throws IOException {
         return buffer.setBytes(index, in, length);
     }
 
     public int setBytes(int index, ScatteringByteChannel in, int length)
             throws IOException {
         return buffer.setBytes(index, in, length);
     }
 
     @Override
     public void writeByte(int value) {
         ensureWritableBytes(1);
         super.writeByte(value);
     }
 
     @Override
     public void writeShort(int value) {
         ensureWritableBytes(2);
         super.writeShort(value);
     }
 
     @Override
     public void writeMedium(int value) {
         ensureWritableBytes(3);
         super.writeMedium(value);
     }
 
     @Override
     public void writeInt(int value) {
         ensureWritableBytes(4);
         super.writeInt(value);
     }
 
     @Override
     public void writeLong(long value) {
         ensureWritableBytes(8);
         super.writeLong(value);
     }
 
     @Override
     public void writeBytes(byte[] src, int srcIndex, int length) {
         ensureWritableBytes(length);
         super.writeBytes(src, srcIndex, length);
     }
 
     @Override
     public void writeBytes(ChannelBuffer src, int srcIndex, int length) {
         ensureWritableBytes(length);
         super.writeBytes(src, srcIndex, length);
     }
 
     @Override
     public void writeBytes(ByteBuffer src) {
         ensureWritableBytes(src.remaining());
         super.writeBytes(src);
     }
 
     @Override
     public int writeBytes(InputStream in, int length) throws IOException {
         ensureWritableBytes(length);
         return super.writeBytes(in, length);
     }
 
     @Override
     public int writeBytes(ScatteringByteChannel in, int length)
             throws IOException {
         ensureWritableBytes(length);
         return super.writeBytes(in, length);
     }
 
     @Override
     public void writeZero(int length) {
         ensureWritableBytes(length);
         super.writeZero(length);
     }
 
     public ChannelBuffer duplicate() {
         return new DuplicatedChannelBuffer(this);
     }
 
     public ChannelBuffer copy(int index, int length) {
         DynamicChannelBuffer copiedBuffer = new DynamicChannelBuffer(order(), Math.max(length, 64), factory());
         copiedBuffer.buffer = buffer.copy(index, length);
         copiedBuffer.setIndex(0, length);
         return copiedBuffer;
     }
 
     public ChannelBuffer slice(int index, int length) {
         if (index == 0) {
             if (length == 0) {
                 return ChannelBuffers.EMPTY_BUFFER;
             }
             return new TruncatedChannelBuffer(this, length);
         } else {
             if (length == 0) {
                 return ChannelBuffers.EMPTY_BUFFER;
             }
             return new SlicedChannelBuffer(this, index, length);
         }
     }
 
     public ByteBuffer toByteBuffer(int index, int length) {
         return buffer.toByteBuffer(index, length);
     }
 }