code: /*
   * Licensed to the Apache Software Foundation (ASF) under one or more
   * contributor license agreements.  See the NOTICE file distributed with
   * this work for additional information regarding copyright ownership.
   * The ASF 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.apache.commons.io.input;
  
  import java.io.DataInput;
  import java.io.EOFException;
  import java.io.IOException;
  import java.io.InputStream;
  
  import org.apache.commons.io.EndianUtils;
  
  /**
   * DataInput for systems relying on little endian data formats.
   * When read, values will be changed from little endian to big 
   * endian formats for internal usage. 
   * <p>
   * <b>Origin of code: </b>Avalon Excalibur (IO)
   *
   * @author <a href="mailto:peter@apache.org">Peter Donald</a>
   * @version CVS $Revision: 995160 $ $Date: 2010-09-08 18:15:52 +0100 (Wed, 08 Sep 2010) $
   */
  public class SwappedDataInputStream extends ProxyInputStream
      implements DataInput
  {
  
      /**
       * Constructs a SwappedDataInputStream.
       *
       * @param input InputStream to read from
       */
      public SwappedDataInputStream( InputStream input )
      {
          super( input );
      }
  
      /**
       * Return <code>{@link #readByte()} != 0</code>
       * @return false if the byte read is zero, otherwise true
       * @throws IOException if an I/O error occurs
       * @throws EOFException if an end of file is reached unexpectedly
       */
      public boolean readBoolean()
          throws IOException, EOFException
      {
          return ( 0 != readByte() );
      }
  
      /**
       * Invokes the delegate's <code>read()</code> method.
       * @return the byte read or -1 if the end of stream
       * @throws IOException if an I/O error occurs
       * @throws EOFException if an end of file is reached unexpectedly
       */
      public byte readByte()
          throws IOException, EOFException
      {
          return (byte)in.read();
      }
  
      /**
       * Reads a character delegating to {@link #readShort()}.
       * @return the byte read or -1 if the end of stream
       * @throws IOException if an I/O error occurs
       * @throws EOFException if an end of file is reached unexpectedly
       */
      public char readChar()
          throws IOException, EOFException
      {
          return (char)readShort();
      }
  
      /**
       * Delegates to {@link EndianUtils#readSwappedDouble(InputStream)}. 
       * @return the read long
       * @throws IOException if an I/O error occurs
       * @throws EOFException if an end of file is reached unexpectedly
       */
      public double readDouble()
          throws IOException, EOFException
      {
          return EndianUtils.readSwappedDouble( in );
      }
  
      /**
       * Delegates to {@link EndianUtils#readSwappedFloat(InputStream)}. 
       * @return the read long
       * @throws IOException if an I/O error occurs
       * @throws EOFException if an end of file is reached unexpectedly
       */
      public float readFloat()
          throws IOException, EOFException
      {
          return EndianUtils.readSwappedFloat( in );
      }
  
      /**
       * Invokes the delegate's <code>read(byte[] data, int, int)</code> method.
       * 
       * @param data the buffer to read the bytes into
       * @throws EOFException if an end of file is reached unexpectedly
       * @throws IOException if an I/O error occurs
       */
      public void readFully( byte[] data )
          throws IOException, EOFException
      {
          readFully( data, 0, data.length );
      }
  
  
      /**
       * Invokes the delegate's <code>read(byte[] data, int, int)</code> method.
       * 
       * @param data the buffer to read the bytes into
       * @param offset The start offset
       * @param length The number of bytes to read
       * @throws EOFException if an end of file is reached unexpectedly
       * @throws IOException if an I/O error occurs
       */
      public void readFully( byte[] data, int offset, int length )
          throws IOException, EOFException
      {
          int remaining = length;
  
          while( remaining > 0 )
          {
              int location = offset + ( length - remaining );
              int count = read( data, location, remaining );
  
              if( -1 == count )
              {
                  throw new EOFException();
              }
  
              remaining -= count;
          }
      }
  
      /**
       * Delegates to {@link EndianUtils#readSwappedInteger(InputStream)}. 
       * @return the read long
       * @throws EOFException if an end of file is reached unexpectedly
       * @throws IOException if an I/O error occurs
       */
      public int readInt()
          throws IOException, EOFException
      {
          return EndianUtils.readSwappedInteger( in );
      }
  
      /**
       * Not currently supported - throws {@link UnsupportedOperationException}.
       * @return the line read
       * @throws EOFException if an end of file is reached unexpectedly
       * @throws IOException if an I/O error occurs
       */
      public String readLine()
          throws IOException, EOFException
      {
          throw new UnsupportedOperationException( 
                  "Operation not supported: readLine()" );
      }
  
      /**
       * Delegates to {@link EndianUtils#readSwappedLong(InputStream)}. 
       * @return the read long
       * @throws EOFException if an end of file is reached unexpectedly
       * @throws IOException if an I/O error occurs
       */
      public long readLong()
          throws IOException, EOFException
      {
          return EndianUtils.readSwappedLong( in );
      }
  
      /**
       * Delegates to {@link EndianUtils#readSwappedShort(InputStream)}. 
       * @return the read long
       * @throws EOFException if an end of file is reached unexpectedly
       * @throws IOException if an I/O error occurs
       */
      public short readShort()
          throws IOException, EOFException
      {
          return EndianUtils.readSwappedShort( in );
      }
  
      /**
       * Invokes the delegate's <code>read()</code> method.
       * @return the byte read or -1 if the end of stream
       * @throws EOFException if an end of file is reached unexpectedly
       * @throws IOException if an I/O error occurs
       */
      public int readUnsignedByte()
          throws IOException, EOFException
      {
          return in.read();
      }
  
      /**
       * Delegates to {@link EndianUtils#readSwappedUnsignedShort(InputStream)}. 
       * @return the read long
       * @throws EOFException if an end of file is reached unexpectedly
       * @throws IOException if an I/O error occurs
       */
      public int readUnsignedShort()
          throws IOException, EOFException
      {
          return EndianUtils.readSwappedUnsignedShort( in );
      }
  
      /**
       * Not currently supported - throws {@link UnsupportedOperationException}.
       * @return UTF String read
       * @throws EOFException if an end of file is reached unexpectedly
       * @throws IOException if an I/O error occurs
       */
      public String readUTF()
          throws IOException, EOFException
      {
          throw new UnsupportedOperationException( 
                  "Operation not supported: readUTF()" );
      }
  
      /**
       * Invokes the delegate's <code>skip(int)</code> method.
       * @param count the number of bytes to skip
       * @return the number of bytes to skipped or -1 if the end of stream
       * @throws EOFException if an end of file is reached unexpectedly
       * @throws IOException if an I/O error occurs
       */
      public int skipBytes( int count )
          throws IOException, EOFException
      {
          return (int)in.skip( count );
      }
  
  }
  