org.eclipse.jetty.util.Utf8StringBuffer Maven / Gradle / Ivy
// ========================================================================
// Copyright (c) 2006-2009 Mort Bay Consulting Pty. Ltd.
// ------------------------------------------------------------------------
// All rights reserved. This program and the accompanying materials
// are made available under the terms of the Eclipse Public License v1.0
// and Apache License v2.0 which accompanies this distribution.
// The Eclipse Public License is available at
// http://www.eclipse.org/legal/epl-v10.html
// The Apache License v2.0 is available at
// http://www.opensource.org/licenses/apache2.0.php
// You may elect to redistribute this code under either of these licenses.
// ========================================================================
package org.eclipse.jetty.util;
/* ------------------------------------------------------------ */
/** UTF-8 StringBuffer.
*
* This class wraps a standard {@link java.lang.StringBuffer} and provides methods to append
* UTF-8 encoded bytes, that are converted into characters.
*
* This class is stateful and up to 6 calls to {@link #append(byte)} may be needed before
* state a character is appended to the string buffer.
*
* The UTF-8 decoding is done by this class and no additional buffers or Readers are used.
* The UTF-8 code was inspired by http://javolution.org
*
* This class is not synchronised and should probably be called Utf8StringBuilder
*/
public class Utf8StringBuffer
{
StringBuffer _buffer;
int _more;
int _bits;
public Utf8StringBuffer()
{
_buffer=new StringBuffer();
}
public Utf8StringBuffer(int capacity)
{
_buffer=new StringBuffer(capacity);
}
public void append(byte[] b,int offset, int length)
{
int end=offset+length;
for (int i=offset; i=0)
{
if (_more>0)
{
_buffer.append('?');
_more=0;
_bits=0;
}
else
_buffer.append((char)(0x7f&b));
}
else if (_more==0)
{
if ((b&0xc0)!=0xc0)
{
// 10xxxxxx
_buffer.append('?');
_more=0;
_bits=0;
}
else
{
if ((b & 0xe0) == 0xc0)
{
//110xxxxx
_more=1;
_bits=b&0x1f;
}
else if ((b & 0xf0) == 0xe0)
{
//1110xxxx
_more=2;
_bits=b&0x0f;
}
else if ((b & 0xf8) == 0xf0)
{
//11110xxx
_more=3;
_bits=b&0x07;
}
else if ((b & 0xfc) == 0xf8)
{
//111110xx
_more=4;
_bits=b&0x03;
}
else if ((b & 0xfe) == 0xfc)
{
//1111110x
_more=5;
_bits=b&0x01;
}
else
{
throw new IllegalArgumentException("!utf8");
}
}
}
else
{
if ((b&0xc0)==0xc0)
{ // 11??????
_buffer.append('?');
_more=0;
_bits=0;
throw new IllegalArgumentException("!utf8");
}
else
{
// 10xxxxxx
_bits=(_bits<<6)|(b&0x3f);
if (--_more==0)
_buffer.append((char)_bits);
}
}
}
public int length()
{
return _buffer.length();
}
public void reset()
{
_buffer.setLength(0);
_more=0;
_bits=0;
}
public StringBuffer getStringBuffer()
{
if (_more!=0)
throw new IllegalStateException("!utf8");
return _buffer;
}
@Override
public String toString()
{
if (_more!=0)
throw new IllegalStateException("!utf8");
return _buffer.toString();
}
}