/*
* 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: 610010 $ $Date: 2008-01-08 14:50:59 +0000 (Tue, 08 Jan 2008) $
*/
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 the true if the byte read is zero, otherwise false
* @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 );
}
}