/*
    * 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.handler.codec.serialization;
  
  import java.io.DataInputStream;
  import java.io.IOException;
  import java.io.InputStream;
  import java.io.ObjectInput;
  import java.io.StreamCorruptedException;
  
  /**
   * An {@link ObjectInput} which is interoperable with {@link ObjectEncoder}
   * and {@link ObjectEncoderOutputStream}.
   */
  public class ObjectDecoderInputStream extends InputStream implements
          ObjectInput {
  
      private final DataInputStream in;
      private final int maxObjectSize;
      private final ClassResolver classResolver;
  
      /**
       * Creates a new {@link ObjectInput}.
       *
       * @param in
       *        the {@link InputStream} where the serialized form will be
       *        read from
       */
      public ObjectDecoderInputStream(InputStream in) {
          this(in, null);
      }
  
      /**
       * Creates a new {@link ObjectInput}.
       *
       * @param in
       *        the {@link InputStream} where the serialized form will be
       *        read from
       * @param classLoader
       *        the {@link ClassLoader} which will load the class of the
       *        serialized object
       */
      public ObjectDecoderInputStream(InputStream in, ClassLoader classLoader) {
          this(in, classLoader, 1048576);
      }
  
      /**
       * Creates a new {@link ObjectInput}.
       *
       * @param in
       *        the {@link InputStream} where the serialized form will be
       *        read from
       * @param maxObjectSize
       *        the maximum byte length of the serialized object.  if the length
       *        of the received object is greater than this value,
       *        a {@link StreamCorruptedException} will be raised.
       */
      public ObjectDecoderInputStream(InputStream in, int maxObjectSize) {
          this(in, null, maxObjectSize);
      }
  
      /**
       * Creates a new {@link ObjectInput}.
       *
       * @param in
       *        the {@link InputStream} where the serialized form will be
       *        read from
       * @param classLoader
       *        the {@link ClassLoader} which will load the class of the
       *        serialized object
       * @param maxObjectSize
       *        the maximum byte length of the serialized object.  if the length
       *        of the received object is greater than this value,
       *        a {@link StreamCorruptedException} will be raised.
       */
      public ObjectDecoderInputStream(InputStream in, ClassLoader classLoader, int maxObjectSize) {
          if (in == null) {
              throw new NullPointerException("in");
          }
          if (maxObjectSize <= 0) {
              throw new IllegalArgumentException("maxObjectSize: " + maxObjectSize);
          }
          if (in instanceof DataInputStream) {
              this.in = (DataInputStream) in;
          } else {
              this.in = new DataInputStream(in);
         }
         classResolver = ClassResolvers.weakCachingResolver(classLoader);
         this.maxObjectSize = maxObjectSize;
     }
 
     public Object readObject() throws ClassNotFoundException, IOException {
         int dataLen = readInt();
         if (dataLen <= 0) {
             throw new StreamCorruptedException("invalid data length: " + dataLen);
         }
         if (dataLen > maxObjectSize) {
             throw new StreamCorruptedException(
                     "data length too big: " + dataLen + " (max: " + maxObjectSize + ')');
         }
 
         return new CompactObjectInputStream(in, classResolver).readObject();
     }
 
     @Override
     public int available() throws IOException {
         return in.available();
     }
 
     @Override
     public void close() throws IOException {
         in.close();
     }
 
     @Override
     public void mark(int readlimit) {
         in.mark(readlimit);
     }
 
     @Override
     public boolean markSupported() {
         return in.markSupported();
     }
 
     @Override
     public int read() throws IOException {
         return in.read();
     }
 
     @Override
     public final int read(byte[] b, int off, int len) throws IOException {
         return in.read(b, off, len);
     }
 
     @Override
     public final int read(byte[] b) throws IOException {
         return in.read(b);
     }
 
     public final boolean readBoolean() throws IOException {
         return in.readBoolean();
     }
 
     public final byte readByte() throws IOException {
         return in.readByte();
     }
 
     public final char readChar() throws IOException {
         return in.readChar();
     }
 
     public final double readDouble() throws IOException {
         return in.readDouble();
     }
 
     public final float readFloat() throws IOException {
         return in.readFloat();
     }
 
     public final void readFully(byte[] b, int off, int len) throws IOException {
         in.readFully(b, off, len);
     }
 
     public final void readFully(byte[] b) throws IOException {
         in.readFully(b);
     }
 
     public final int readInt() throws IOException {
         return in.readInt();
     }
 
     @Deprecated
     public final String readLine() throws IOException {
         return in.readLine();
     }
 
     public final long readLong() throws IOException {
         return in.readLong();
     }
 
     public final short readShort() throws IOException {
         return in.readShort();
     }
 
     public final int readUnsignedByte() throws IOException {
         return in.readUnsignedByte();
     }
 
     public final int readUnsignedShort() throws IOException {
         return in.readUnsignedShort();
     }
 
     public final String readUTF() throws IOException {
         return in.readUTF();
     }
 
     @Override
     public void reset() throws IOException {
         in.reset();
     }
 
     @Override
     public long skip(long n) throws IOException {
         return in.skip(n);
     }
 
     public final int skipBytes(int n) throws IOException {
         return in.skipBytes(n);
     }
 }