/*
* 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.mina.filter.codec.textline;
import java.nio.charset.CharacterCodingException;
import java.nio.charset.Charset;
import java.nio.charset.CharsetDecoder;
import org.apache.mina.common.BufferDataException;
import org.apache.mina.common.ByteBuffer;
import org.apache.mina.common.IoSession;
import org.apache.mina.filter.codec.ProtocolDecoder;
import org.apache.mina.filter.codec.ProtocolDecoderOutput;
import org.apache.mina.util.CharsetUtil;
/**
* A {@link ProtocolDecoder} which decodes a text line into a string.
*
* @author The Apache Directory Project (mina-dev@directory.apache.org)
* @version $Rev: 500930 $, $Date: 2007-01-29 12:24:59 +0900 (월, 29 1월 2007) $,
*/
public class TextLineDecoder implements ProtocolDecoder
{
private static final String CONTEXT = TextLineDecoder.class.getName() + ".context";
private final Charset charset;
private final LineDelimiter delimiter;
private ByteBuffer delimBuf;
private int maxLineLength = 1024;
/**
* Creates a new instance with the current default {@link Charset}
* and {@link LineDelimiter#AUTO} delimiter.
*/
public TextLineDecoder()
{
this( CharsetUtil.getDefaultCharset(), LineDelimiter.AUTO );
}
/**
* Creates a new instance with the spcified <tt>charset</tt>
* and {@link LineDelimiter#AUTO} delimiter.
*/
public TextLineDecoder( Charset charset )
{
this( charset, LineDelimiter.AUTO );
}
/**
* Creates a new instance with the specified <tt>charset</tt>
* and the specified <tt>delimiter</tt>.
*/
public TextLineDecoder( Charset charset, LineDelimiter delimiter )
{
if( charset == null )
{
throw new NullPointerException( "charset" );
}
if( delimiter == null )
{
throw new NullPointerException( "delimiter" );
}
this.charset = charset;
this.delimiter = delimiter;
}
/**
* Returns the allowed maximum size of the line to be decoded.
* If the size of the line to be decoded exceeds this value, the
* decoder will throw a {@link BufferDataException}. The default
* value is <tt>1024</tt> (1KB).
*/
public int getMaxLineLength()
{
return maxLineLength;
}
/**
* Sets the allowed maximum size of the line to be decoded.
* If the size of the line to be decoded exceeds this value, the
* decoder will throw a {@link BufferDataException}. The default
* value is <tt>1024</tt> (1KB).
*/
public void setMaxLineLength( int maxLineLength )
{
if( maxLineLength <= 0 )
{
throw new IllegalArgumentException( "maxLineLength: " + maxLineLength );
}
this.maxLineLength = maxLineLength;
}
public void decode( IoSession session, ByteBuffer in,
ProtocolDecoderOutput out )
throws Exception
{
Context ctx = getContext(session);
if( LineDelimiter.AUTO.equals( delimiter ) )
{
ctx.setMatchCount(
decodeAuto(
in,
ctx.getBuffer(),
ctx.getMatchCount(),
ctx.getDecoder(),
out ) );
}
else
{
ctx.setMatchCount(
decodeNormal(
in,
ctx.getBuffer(),
ctx.getMatchCount(),
ctx.getDecoder(),
out ) );
}
}
private Context getContext(IoSession session) {
Context ctx;
ctx = ( Context ) session.getAttribute( CONTEXT );
if( ctx == null )
{
ctx = new Context();
session.setAttribute( CONTEXT, ctx );
}
return ctx;
}
public void finishDecode( IoSession session, ProtocolDecoderOutput out ) throws Exception
{
}
public void dispose( IoSession session ) throws Exception
{
Context ctx = ( Context ) session.getAttribute( CONTEXT );
if( ctx != null )
{
ctx.getBuffer().release();
session.removeAttribute( CONTEXT );
}
}
private int decodeAuto( ByteBuffer in, ByteBuffer buf, int matchCount, CharsetDecoder decoder, ProtocolDecoderOutput out ) throws CharacterCodingException
{
// Try to find a match
int oldPos = in.position();
int oldLimit = in.limit();
while( in.hasRemaining() )
{
byte b = in.get();
boolean matched = false;
switch( b )
{
case '\r':
// Might be Mac, but we don't auto-detect Mac EOL
// to avoid confusion.
matchCount ++;
break;
case '\n':
// UNIX
matchCount ++;
matched = true;
break;
default:
matchCount = 0;
}
if( matched )
{
// Found a match.
int pos = in.position();
in.limit( pos );
in.position( oldPos );
buf.put( in );
if( buf.position() > maxLineLength )
{
throw new BufferDataException( "Line is too long: " + buf.position() );
}
buf.flip();
buf.limit( buf.limit() - matchCount );
out.write( buf.getString( decoder ) );
buf.clear();
in.limit( oldLimit );
in.position( pos );
oldPos = pos;
matchCount = 0;
}
}
// Put remainder to buf.
in.position( oldPos );
buf.put( in );
return matchCount;
}
private int decodeNormal( ByteBuffer in, ByteBuffer buf, int matchCount, CharsetDecoder decoder, ProtocolDecoderOutput out ) throws CharacterCodingException
{
// Convert delimiter to ByteBuffer if not done yet.
if( delimBuf == null )
{
ByteBuffer tmp = ByteBuffer.allocate( 2 ).setAutoExpand( true );
tmp.putString( delimiter.getValue(), charset.newEncoder() );
tmp.flip();
delimBuf = tmp;
}
// Try to find a match
int oldPos = in.position();
int oldLimit = in.limit();
while( in.hasRemaining() )
{
byte b = in.get();
if( delimBuf.get( matchCount ) == b )
{
matchCount ++;
if( matchCount == delimBuf.limit() )
{
// Found a match.
int pos = in.position();
in.limit( pos );
in.position( oldPos );
buf.put( in );
if( buf.position() > maxLineLength )
{
throw new BufferDataException( "Line is too long: " + buf.position() );
}
buf.flip();
buf.limit( buf.limit() - matchCount );
out.write( buf.getString( decoder ) );
buf.clear();
in.limit( oldLimit );
in.position( pos );
oldPos = pos;
matchCount = 0;
}
}
else
{
matchCount = 0;
}
}
// Put remainder to buf.
in.position( oldPos );
buf.put( in );
return matchCount;
}
private class Context
{
private final CharsetDecoder decoder;
private final ByteBuffer buf;
private int matchCount = 0;
private Context()
{
decoder = charset.newDecoder();
buf = ByteBuffer.allocate( 80 ).setAutoExpand( true );
}
public CharsetDecoder getDecoder()
{
return decoder;
}
public ByteBuffer getBuffer()
{
return buf;
}
public int getMatchCount()
{
return matchCount;
}
public void setMatchCount( int matchCount )
{
this.matchCount = matchCount;
}
}
}