/*
    * 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.nio.ByteBuffer;
  import java.nio.ByteOrder;
  
  /**
   * A {@link ChannelBufferFactory} which merely allocates a heap buffer with
   * the specified capacity.  {@link HeapChannelBufferFactory} should perform
   * very well in most situations because it relies on the JVM garbage collector,
   * which is highly optimized for heap allocation.
   */
  public class HeapChannelBufferFactory extends AbstractChannelBufferFactory {
  
      private static final HeapChannelBufferFactory INSTANCE_BE =
          new HeapChannelBufferFactory(ByteOrder.BIG_ENDIAN);
  
      private static final HeapChannelBufferFactory INSTANCE_LE =
          new HeapChannelBufferFactory(ByteOrder.LITTLE_ENDIAN);
  
      public static ChannelBufferFactory getInstance() {
          return INSTANCE_BE;
      }
  
      public static ChannelBufferFactory getInstance(ByteOrder endianness) {
          if (endianness == ByteOrder.BIG_ENDIAN) {
              return INSTANCE_BE;
          } else if (endianness == ByteOrder.LITTLE_ENDIAN) {
              return INSTANCE_LE;
          } else if (endianness == null) {
              throw new NullPointerException("endianness");
          } else {
              throw new IllegalStateException("Should not reach here");
          }
      }
  
      /**
       * Creates a new factory whose default {@link ByteOrder} is
       * {@link ByteOrder#BIG_ENDIAN}.
       */
      public HeapChannelBufferFactory() {
      }
  
      /**
       * Creates a new factory with the specified default {@link ByteOrder}.
       *
       * @param defaultOrder the default {@link ByteOrder} of this factory
       */
      public HeapChannelBufferFactory(ByteOrder defaultOrder) {
          super(defaultOrder);
      }
  
      public ChannelBuffer getBuffer(ByteOrder order, int capacity) {
          return ChannelBuffers.buffer(order, capacity);
      }
  
      public ChannelBuffer getBuffer(ByteOrder order, byte[] array, int offset, int length) {
          return ChannelBuffers.wrappedBuffer(order, array, offset, length);
      }
  
      public ChannelBuffer getBuffer(ByteBuffer nioBuffer) {
          if (nioBuffer.hasArray()) {
              return ChannelBuffers.wrappedBuffer(nioBuffer);
          }
  
          ChannelBuffer buf = getBuffer(nioBuffer.order(), nioBuffer.remaining());
          int pos = nioBuffer.position();
          buf.writeBytes(nioBuffer);
          nioBuffer.position(pos);
          return buf;
      }
  }