org/sonews/util/io/VarCharsetReader.java
author chris <chris@marvin>
Fri Jun 26 16:48:50 2009 +0200 (2009-06-26)
changeset 1 6fceb66e1ad7
permissions -rw-r--r--
Hooray... sonews/0.5.0 final

HG: Enter commit message. Lines beginning with 'HG:' are removed.
HG: Remove all lines to abort the collapse operation.
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/*
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 *   SONEWS News Server
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 *   see AUTHORS for the list of contributors
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 *
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 *   This program is free software: you can redistribute it and/or modify
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 *   it under the terms of the GNU General Public License as published by
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 *   the Free Software Foundation, either version 3 of the License, or
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 *   (at your option) any later version.
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 *
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 *   This program is distributed in the hope that it will be useful,
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 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
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 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
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 *   GNU General Public License for more details.
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 *
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 *   You should have received a copy of the GNU General Public License
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 *   along with this program.  If not, see <http://www.gnu.org/licenses/>.
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 */
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package org.sonews.util.io;
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import java.io.IOException;
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import java.io.InputStream;
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import java.nio.ByteBuffer;
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import java.nio.charset.Charset;
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/**
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 * InputStream that can change its decoding charset while reading from the
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 * underlying byte based stream.
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 * @author Christian Lins
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 * @since sonews/0.5.0
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 */
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public class VarCharsetReader
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{
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  private final ByteBuffer buf = ByteBuffer.allocate(4096);
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  private InputStream in;
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  public VarCharsetReader(final InputStream in)
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  {
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    if(in == null)
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    {
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      throw new IllegalArgumentException("null InputStream");
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    }
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    this.in = in;
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  }
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  /**
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   * Reads up to the next newline character and returns the line as String.
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   * The String is decoded using the given charset.
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   */
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  public String readLine(Charset charset)
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    throws IOException
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  {    
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    byte[] byteBuf = new byte[1];
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    String bufStr;
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    for(;;)
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    {
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      int read = this.in.read(byteBuf);
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      if(read == 0)
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      {
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        continue;
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      }
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      else if(read == -1)
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      {
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        this.in = null;
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        bufStr  = new String(this.buf.array(), 0, this.buf.position(), charset);
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        break;
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      }
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      else if(byteBuf[0] == 10) // Is this safe? \n
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      {
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        bufStr  = new String(this.buf.array(), 0, this.buf.position(), charset);
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        break;
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      }
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      else if(byteBuf[0] == 13) // \r
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      { // Skip
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        continue;
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      }
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      else
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      {
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        this.buf.put(byteBuf[0]);
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      }
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    }
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    this.buf.clear();
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    return bufStr;
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  }
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}