/*
    * 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 io.netty.handler.codec;
  
  import io.netty.buffer.ByteBuf;
  import io.netty.buffer.ByteBufAllocator;
  import io.netty.buffer.ByteBufProcessor;
  import io.netty.buffer.SwappedByteBuf;
  import io.netty.buffer.Unpooled;
  import io.netty.util.Signal;
  import io.netty.util.internal.StringUtil;
  
  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;
  import java.nio.charset.Charset;
  
  /**
   * Special {@link ByteBuf} implementation which is used by the {@link ReplayingDecoder}
   */
  final class ReplayingDecoderByteBuf extends ByteBuf {
  
      private static final Signal REPLAY = ReplayingDecoder.REPLAY;
  
      private ByteBuf buffer;
      private boolean terminated;
      private SwappedByteBuf swapped;
  
      static final ReplayingDecoderByteBuf EMPTY_BUFFER = new ReplayingDecoderByteBuf(Unpooled.EMPTY_BUFFER);
  
      static {
          EMPTY_BUFFER.terminate();
      }
  
      ReplayingDecoderByteBuf() { }
  
      ReplayingDecoderByteBuf(ByteBuf buffer) {
          setCumulation(buffer);
      }
  
      void setCumulation(ByteBuf buffer) {
          this.buffer = buffer;
      }
  
      void terminate() {
          terminated = true;
      }
  
      @Override
      public int capacity() {
          if (terminated) {
              return buffer.capacity();
          } else {
              return Integer.MAX_VALUE;
          }
      }
  
      @Override
      public ByteBuf capacity(int newCapacity) {
          reject();
          return this;
      }
  
      @Override
      public int maxCapacity() {
          return capacity();
      }
  
      @Override
      public ByteBufAllocator alloc() {
          return buffer.alloc();
      }
  
      @Override
      public boolean isDirect() {
          return buffer.isDirect();
      }
  
      @Override
      public boolean hasArray() {
          return false;
      }
  
     @Override
     public byte[] array() {
         throw new UnsupportedOperationException();
     }
 
     @Override
     public int arrayOffset() {
         throw new UnsupportedOperationException();
     }
 
     @Override
     public boolean hasMemoryAddress() {
         return false;
     }
 
     @Override
     public long memoryAddress() {
         throw new UnsupportedOperationException();
     }
 
     @Override
     public ByteBuf clear() {
         reject();
         return this;
     }
 
     @Override
     public boolean equals(Object obj) {
         return this == obj;
     }
 
     @Override
     public int compareTo(ByteBuf buffer) {
         reject();
         return 0;
     }
 
     @Override
     public ByteBuf copy() {
         reject();
         return this;
     }
 
     @Override
     public ByteBuf copy(int index, int length) {
         checkIndex(index, length);
         return buffer.copy(index, length);
     }
 
     @Override
     public ByteBuf discardReadBytes() {
         reject();
         return this;
     }
 
     @Override
     public ByteBuf ensureWritable(int writableBytes) {
         reject();
         return this;
     }
 
     @Override
     public int ensureWritable(int minWritableBytes, boolean force) {
         reject();
         return 0;
     }
 
     @Override
     public ByteBuf duplicate() {
         reject();
         return this;
     }
 
     @Override
     public boolean getBoolean(int index) {
         checkIndex(index, 1);
         return buffer.getBoolean(index);
     }
 
     @Override
     public byte getByte(int index) {
         checkIndex(index, 1);
         return buffer.getByte(index);
     }
 
     @Override
     public short getUnsignedByte(int index) {
         checkIndex(index, 1);
         return buffer.getUnsignedByte(index);
     }
 
     @Override
     public ByteBuf getBytes(int index, byte[] dst, int dstIndex, int length) {
         checkIndex(index, length);
         buffer.getBytes(index, dst, dstIndex, length);
         return this;
     }
 
     @Override
     public ByteBuf getBytes(int index, byte[] dst) {
         checkIndex(index, dst.length);
         buffer.getBytes(index, dst);
         return this;
     }
 
     @Override
     public ByteBuf getBytes(int index, ByteBuffer dst) {
         reject();
         return this;
     }
 
     @Override
     public ByteBuf getBytes(int index, ByteBuf dst, int dstIndex, int length) {
         checkIndex(index, length);
         buffer.getBytes(index, dst, dstIndex, length);
         return this;
     }
 
     @Override
     public ByteBuf getBytes(int index, ByteBuf dst, int length) {
         reject();
         return this;
     }
 
     @Override
     public ByteBuf getBytes(int index, ByteBuf dst) {
         reject();
         return this;
     }
 
     @Override
     public int getBytes(int index, GatheringByteChannel out, int length) {
         reject();
         return 0;
     }
 
     @Override
     public ByteBuf getBytes(int index, OutputStream out, int length) {
         reject();
         return this;
     }
 
     @Override
     public int getInt(int index) {
         checkIndex(index, 4);
         return buffer.getInt(index);
     }
 
     @Override
     public long getUnsignedInt(int index) {
         checkIndex(index, 4);
         return buffer.getUnsignedInt(index);
     }
 
     @Override
     public long getLong(int index) {
         checkIndex(index, 8);
         return buffer.getLong(index);
     }
 
     @Override
     public int getMedium(int index) {
         checkIndex(index, 3);
         return buffer.getMedium(index);
     }
 
     @Override
     public int getUnsignedMedium(int index) {
         checkIndex(index, 3);
         return buffer.getUnsignedMedium(index);
     }
 
     @Override
     public short getShort(int index) {
         checkIndex(index, 2);
         return buffer.getShort(index);
     }
 
     @Override
     public int getUnsignedShort(int index) {
         checkIndex(index, 2);
         return buffer.getUnsignedShort(index);
     }
 
     @Override
     public char getChar(int index) {
         checkIndex(index, 2);
         return buffer.getChar(index);
     }
 
     @Override
     public float getFloat(int index) {
         checkIndex(index, 4);
         return buffer.getFloat(index);
     }
 
     @Override
     public double getDouble(int index) {
         checkIndex(index, 8);
         return buffer.getDouble(index);
     }
 
     @Override
     public int hashCode() {
         reject();
         return 0;
     }
 
     @Override
     public int indexOf(int fromIndex, int toIndex, byte value) {
         if (fromIndex == toIndex) {
             return -1;
         }
 
         if (Math.max(fromIndex, toIndex) > buffer.writerIndex()) {
             throw REPLAY;
         }
 
         return buffer.indexOf(fromIndex, toIndex, value);
     }
 
     @Override
     public int bytesBefore(byte value) {
         int bytes = buffer.bytesBefore(value);
         if (bytes < 0) {
             throw REPLAY;
         }
         return bytes;
     }
 
     @Override
     public int bytesBefore(int length, byte value) {
         final int readerIndex = buffer.readerIndex();
         return bytesBefore(readerIndex, buffer.writerIndex() - readerIndex, value);
     }
 
     @Override
     public int bytesBefore(int index, int length, byte value) {
         final int writerIndex = buffer.writerIndex();
         if (index >= writerIndex) {
             throw REPLAY;
         }
 
         if (index <= writerIndex - length) {
             return buffer.bytesBefore(index, length, value);
         }
 
         int res = buffer.bytesBefore(index, writerIndex - index, value);
         if (res < 0) {
             throw REPLAY;
         } else {
             return res;
         }
     }
 
     @Override
     public int forEachByte(ByteBufProcessor processor) {
         int ret = buffer.forEachByte(processor);
         if (ret < 0) {
             throw REPLAY;
         } else {
             return ret;
         }
     }
 
     @Override
     public int forEachByte(int index, int length, ByteBufProcessor processor) {
         final int writerIndex = buffer.writerIndex();
         if (index >= writerIndex) {
             throw REPLAY;
         }
 
         if (index <= writerIndex - length) {
             return buffer.forEachByte(index, length, processor);
         }
 
         int ret = buffer.forEachByte(index, writerIndex - index, processor);
         if (ret < 0) {
             throw REPLAY;
         } else {
             return ret;
         }
     }
 
     @Override
     public int forEachByteDesc(ByteBufProcessor processor) {
         if (terminated) {
             return buffer.forEachByteDesc(processor);
         } else {
             reject();
             return 0;
         }
     }
 
     @Override
     public int forEachByteDesc(int index, int length, ByteBufProcessor processor) {
         if (index + length > buffer.writerIndex()) {
             throw REPLAY;
         }
 
         return buffer.forEachByteDesc(index, length, processor);
     }
 
     @Override
     public ByteBuf markReaderIndex() {
         buffer.markReaderIndex();
         return this;
     }
 
     @Override
     public ByteBuf markWriterIndex() {
         reject();
         return this;
     }
 
     @Override
     public ByteOrder order() {
         return buffer.order();
     }
 
     @Override
     public ByteBuf order(ByteOrder endianness) {
         if (endianness == null) {
             throw new NullPointerException("endianness");
         }
         if (endianness == order()) {
             return this;
         }
 
         SwappedByteBuf swapped = this.swapped;
         if (swapped == null) {
             this.swapped = swapped = new SwappedByteBuf(this);
         }
         return swapped;
     }
 
     @Override
     public boolean isReadable() {
         return terminated? buffer.isReadable() : true;
     }
 
     @Override
     public boolean isReadable(int size) {
         return terminated? buffer.isReadable(size) : true;
     }
 
     @Override
     public int readableBytes() {
         if (terminated) {
             return buffer.readableBytes();
         } else {
             return Integer.MAX_VALUE - buffer.readerIndex();
         }
     }
 
     @Override
     public boolean readBoolean() {
         checkReadableBytes(1);
         return buffer.readBoolean();
     }
 
     @Override
     public byte readByte() {
         checkReadableBytes(1);
         return buffer.readByte();
     }
 
     @Override
     public short readUnsignedByte() {
         checkReadableBytes(1);
         return buffer.readUnsignedByte();
     }
 
     @Override
     public ByteBuf readBytes(byte[] dst, int dstIndex, int length) {
         checkReadableBytes(length);
         buffer.readBytes(dst, dstIndex, length);
         return this;
     }
 
     @Override
     public ByteBuf readBytes(byte[] dst) {
         checkReadableBytes(dst.length);
         buffer.readBytes(dst);
         return this;
     }
 
     @Override
     public ByteBuf readBytes(ByteBuffer dst) {
         reject();
         return this;
     }
 
     @Override
     public ByteBuf readBytes(ByteBuf dst, int dstIndex, int length) {
         checkReadableBytes(length);
         buffer.readBytes(dst, dstIndex, length);
         return this;
     }
 
     @Override
     public ByteBuf readBytes(ByteBuf dst, int length) {
         reject();
         return this;
     }
 
     @Override
     public ByteBuf readBytes(ByteBuf dst) {
         checkReadableBytes(dst.writableBytes());
         buffer.readBytes(dst);
         return this;
     }
 
     @Override
     public int readBytes(GatheringByteChannel out, int length) {
         reject();
         return 0;
     }
 
     @Override
     public ByteBuf readBytes(int length) {
         checkReadableBytes(length);
         return buffer.readBytes(length);
     }
 
     @Override
     public ByteBuf readSlice(int length) {
         checkReadableBytes(length);
         return buffer.readSlice(length);
     }
 
     @Override
     public ByteBuf readBytes(OutputStream out, int length) {
         reject();
         return this;
     }
 
     @Override
     public int readerIndex() {
         return buffer.readerIndex();
     }
 
     @Override
     public ByteBuf readerIndex(int readerIndex) {
         buffer.readerIndex(readerIndex);
         return this;
     }
 
     @Override
     public int readInt() {
         checkReadableBytes(4);
         return buffer.readInt();
     }
 
     @Override
     public long readUnsignedInt() {
         checkReadableBytes(4);
         return buffer.readUnsignedInt();
     }
 
     @Override
     public long readLong() {
         checkReadableBytes(8);
         return buffer.readLong();
     }
 
     @Override
     public int readMedium() {
         checkReadableBytes(3);
         return buffer.readMedium();
     }
 
     @Override
     public int readUnsignedMedium() {
         checkReadableBytes(3);
         return buffer.readUnsignedMedium();
     }
 
     @Override
     public short readShort() {
         checkReadableBytes(2);
         return buffer.readShort();
     }
 
     @Override
     public int readUnsignedShort() {
         checkReadableBytes(2);
         return buffer.readUnsignedShort();
     }
 
     @Override
     public char readChar() {
         checkReadableBytes(2);
         return buffer.readChar();
     }
 
     @Override
     public float readFloat() {
         checkReadableBytes(4);
         return buffer.readFloat();
     }
 
     @Override
     public double readDouble() {
         checkReadableBytes(8);
         return buffer.readDouble();
     }
 
     @Override
     public ByteBuf resetReaderIndex() {
         buffer.resetReaderIndex();
         return this;
     }
 
     @Override
     public ByteBuf resetWriterIndex() {
         reject();
         return this;
     }
 
     @Override
     public ByteBuf setBoolean(int index, boolean value) {
         reject();
         return this;
     }
 
     @Override
     public ByteBuf setByte(int index, int value) {
         reject();
         return this;
     }
 
     @Override
     public ByteBuf setBytes(int index, byte[] src, int srcIndex, int length) {
         reject();
         return this;
     }
 
     @Override
     public ByteBuf setBytes(int index, byte[] src) {
         reject();
         return this;
     }
 
     @Override
     public ByteBuf setBytes(int index, ByteBuffer src) {
         reject();
         return this;
     }
 
     @Override
     public ByteBuf setBytes(int index, ByteBuf src, int srcIndex, int length) {
         reject();
         return this;
     }
 
     @Override
     public ByteBuf setBytes(int index, ByteBuf src, int length) {
         reject();
         return this;
     }
 
     @Override
     public ByteBuf setBytes(int index, ByteBuf src) {
         reject();
         return this;
     }
 
     @Override
     public int setBytes(int index, InputStream in, int length) {
         reject();
         return 0;
     }
 
     @Override
     public ByteBuf setZero(int index, int length) {
         reject();
         return this;
     }
 
     @Override
     public int setBytes(int index, ScatteringByteChannel in, int length) {
         reject();
         return 0;
     }
 
     @Override
     public ByteBuf setIndex(int readerIndex, int writerIndex) {
         reject();
         return this;
     }
 
     @Override
     public ByteBuf setInt(int index, int value) {
         reject();
         return this;
     }
 
     @Override
     public ByteBuf setLong(int index, long value) {
         reject();
         return this;
     }
 
     @Override
     public ByteBuf setMedium(int index, int value) {
         reject();
         return this;
     }
 
     @Override
     public ByteBuf setShort(int index, int value) {
         reject();
         return this;
     }
 
     @Override
     public ByteBuf setChar(int index, int value) {
         reject();
         return this;
     }
 
     @Override
     public ByteBuf setFloat(int index, float value) {
         reject();
         return this;
     }
 
     @Override
     public ByteBuf setDouble(int index, double value) {
         reject();
         return this;
     }
 
     @Override
     public ByteBuf skipBytes(int length) {
         checkReadableBytes(length);
         buffer.skipBytes(length);
         return this;
     }
 
     @Override
     public ByteBuf slice() {
         reject();
         return this;
     }
 
     @Override
     public ByteBuf slice(int index, int length) {
         checkIndex(index, length);
         return buffer.slice(index, length);
     }
 
     @Override
     public int nioBufferCount() {
         return buffer.nioBufferCount();
     }
 
     @Override
     public ByteBuffer nioBuffer() {
         reject();
         return null;
     }
 
     @Override
     public ByteBuffer nioBuffer(int index, int length) {
         checkIndex(index, length);
         return buffer.nioBuffer(index, length);
     }
 
     @Override
     public ByteBuffer[] nioBuffers() {
         reject();
         return null;
     }
 
     @Override
     public ByteBuffer[] nioBuffers(int index, int length) {
         checkIndex(index, length);
         return buffer.nioBuffers(index, length);
     }
 
     @Override
     public ByteBuffer internalNioBuffer(int index, int length) {
         checkIndex(index, length);
         return buffer.internalNioBuffer(index, length);
     }
 
     @Override
     public String toString(int index, int length, Charset charset) {
         checkIndex(index, length);
         return buffer.toString(index, length, charset);
     }
 
     @Override
     public String toString(Charset charsetName) {
         reject();
         return null;
     }
 
     @Override
     public String toString() {
         return StringUtil.simpleClassName(this) + '(' +
                "ridx=" +
                readerIndex() +
                ", " +
                "widx=" +
                writerIndex() +
                ')';
     }
 
     @Override
     public boolean isWritable() {
         return false;
     }
 
     @Override
     public boolean isWritable(int size) {
         return false;
     }
 
     @Override
     public int writableBytes() {
         return 0;
     }
 
     @Override
     public int maxWritableBytes() {
         return 0;
     }
 
     @Override
     public ByteBuf writeBoolean(boolean value) {
         reject();
         return this;
     }
 
     @Override
     public ByteBuf writeByte(int value) {
         reject();
         return this;
     }
 
     @Override
     public ByteBuf writeBytes(byte[] src, int srcIndex, int length) {
         reject();
         return this;
     }
 
     @Override
     public ByteBuf writeBytes(byte[] src) {
         reject();
         return this;
     }
 
     @Override
     public ByteBuf writeBytes(ByteBuffer src) {
         reject();
         return this;
     }
 
     @Override
     public ByteBuf writeBytes(ByteBuf src, int srcIndex, int length) {
         reject();
         return this;
     }
 
     @Override
     public ByteBuf writeBytes(ByteBuf src, int length) {
         reject();
         return this;
     }
 
     @Override
     public ByteBuf writeBytes(ByteBuf src) {
         reject();
         return this;
     }
 
     @Override
     public int writeBytes(InputStream in, int length) {
         reject();
         return 0;
     }
 
     @Override
     public int writeBytes(ScatteringByteChannel in, int length) {
         reject();
         return 0;
     }
 
     @Override
     public ByteBuf writeInt(int value) {
         reject();
         return this;
     }
 
     @Override
     public ByteBuf writeLong(long value) {
         reject();
         return this;
     }
 
     @Override
     public ByteBuf writeMedium(int value) {
         reject();
         return this;
     }
 
     @Override
     public ByteBuf writeZero(int length) {
         reject();
         return this;
     }
 
     @Override
     public int writerIndex() {
         return buffer.writerIndex();
     }
 
     @Override
     public ByteBuf writerIndex(int writerIndex) {
         reject();
         return this;
     }
 
     @Override
     public ByteBuf writeShort(int value) {
         reject();
         return this;
     }
 
     @Override
     public ByteBuf writeChar(int value) {
         reject();
         return this;
     }
 
     @Override
     public ByteBuf writeFloat(float value) {
         reject();
         return this;
     }
 
     @Override
     public ByteBuf writeDouble(double value) {
         reject();
         return this;
     }
 
     private void checkIndex(int index, int length) {
         if (index + length > buffer.writerIndex()) {
             throw REPLAY;
         }
     }
 
     private void checkReadableBytes(int readableBytes) {
         if (buffer.readableBytes() < readableBytes) {
             throw REPLAY;
         }
     }
 
     @Override
     public ByteBuf discardSomeReadBytes() {
         reject();
         return this;
     }
 
     @Override
     public int refCnt() {
         return buffer.refCnt();
     }
 
     @Override
     public ByteBuf retain() {
         reject();
         return this;
     }
 
     @Override
     public ByteBuf retain(int increment) {
         reject();
         return this;
     }
 
     @Override
     public boolean release() {
         reject();
         return false;
     }
 
     @Override
     public boolean release(int decrement) {
         reject();
         return false;
     }
 
     @Override
     public ByteBuf unwrap() {
         reject();
         return this;
     }
 
     private static void reject() {
         throw new UnsupportedOperationException("not a replayable operation");
     }
 }