libjava/classpath/gnu/java/net/protocol/http/ChunkedInputStream.java

   1 /* ChunkedInputStream.java --
   2    Copyright (C) 2004, 2006 Free Software Foundation, Inc.
   3
   4 This file is part of GNU Classpath.
   5
   6 GNU Classpath is free software; you can redistribute it and/or modify
   7 it under the terms of the GNU General Public License as published by
   8 the Free Software Foundation; either version 2, or (at your option)
   9 any later version.
  10
  11 GNU Classpath is distributed in the hope that it will be useful, but
  12 WITHOUT ANY WARRANTY; without even the implied warranty of
  13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14 General Public License for more details.
  15
  16 You should have received a copy of the GNU General Public License
  17 along with GNU Classpath; see the file COPYING.  If not, write to the
  18 Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  19 02110-1301 USA.
  20
  21 Linking this library statically or dynamically with other modules is
  22 making a combined work based on this library.  Thus, the terms and
  23 conditions of the GNU General Public License cover the whole
  24 combination.
  25
  26 As a special exception, the copyright holders of this library give you
  27 permission to link this library with independent modules to produce an
  28 executable, regardless of the license terms of these independent
  29 modules, and to copy and distribute the resulting executable under
  30 terms of your choice, provided that you also meet, for each linked
  31 independent module, the terms and conditions of the license of that
  32 module.  An independent module is a module which is not derived from
  33 or based on this library.  If you modify this library, you may extend
  34 this exception to your version of the library, but you are not
  35 obligated to do so.  If you do not wish to do so, delete this
  36 exception statement from your version. */
  37
  38
  39 package gnu.java.net.protocol.http;
  40
  41 import java.io.IOException;
  42 import java.io.InputStream;
  43 import java.net.ProtocolException;
  44
  45
  46 //
  47 // Note that we rely on the implemtation of skip() in the super class
  48 // (InputStream) calling our read methods to account for chunk headers
  49 // while skipping.
  50 //
  51
  52
  53 /**
  54  * Input stream wrapper for the "chunked" transfer-coding.
  55  *
  56  * @author Chris Burdess (dog@gnu.org)
  57  */
  58 public class ChunkedInputStream
  59   extends InputStream
  60 {
  61
  62   private static final byte CR = 0x0d;
  63   private static final byte LF = 0x0a;
  64
  65   Headers headers;
  66
  67   /** The underlying stream. */
  68   private InputStream in;
  69
  70   /** Size of the chunk we're reading.  */
  71   int size;
  72   /** Number of bytes we've read in this chunk.  */
  73   int count;
  74   /**
  75    * True when we should read meta-information, false when we should
  76    * read data.
  77    */
  78   boolean meta;
  79   /** True when we've hit EOF.  */
  80   boolean eof;
  81
  82   /**
  83    * Constructor.
  84    * @param in the response socket input stream
  85    * @param headers the headers to receive additional header lines
  86    */
  87   public ChunkedInputStream(InputStream in, Headers headers)
  88   {
  89     this.in = in;
  90     this.headers = headers;
  91     size = -1;
  92     count = 0;
  93     meta = true;
  94   }
  95
  96   public int read()
  97     throws IOException
  98   {
  99     byte[] buf = new byte[1];
 100     int len = read(buf, 0, 1);
 101     if (len == -1)
 102       {
 103         return -1;
 104       }
 105     return 0xff & buf[0];
 106   }
 107
 108   public synchronized int read(byte[] buffer, int offset, int length)
 109     throws IOException
 110   {
 111     if (eof)
 112       {
 113         return -1;
 114       }
 115     if (meta)
 116       {
 117         // Read chunk header
 118         int c, last = 0;
 119         boolean seenSemi = false;
 120         StringBuilder buf = new StringBuilder();
 121         do
 122           {
 123             c = in.read();
 124             if (c == 0x3b) // ;
 125               {
 126                 seenSemi = true;
 127               }
 128             else if (c == 0x0a && last == 0x0d) // CRLF
 129               {
 130                 try
 131                   {
 132                     size = Integer.parseInt(buf.toString(), 16);
 133                   }
 134                 catch (NumberFormatException nfe)
 135                   {
 136                     IOException ioe = new IOException("Bad chunk header");
 137                     ioe.initCause(nfe);
 138                     // Unrecoverable.  Don't try to read more.
 139                     in.close();
 140                     throw ioe;
 141                   }
 142                 break;
 143               }
 144             else if (!seenSemi && c >= 0x30)
 145               {
 146                 buf.append ((char) c);
 147               }
 148             last = c;
 149           }
 150         while(c != -1);
 151         count = 0;
 152         meta = false;
 153       }
 154     if (size == 0)
 155       {
 156         // Read trailer
 157         headers.parse(in);
 158         eof = true;
 159         return -1;
 160       }
 161     else
 162       {
 163         int canRead = Math.min(size - count, length);
 164         int len = in.read(buffer, offset, canRead);
 165         if (len == -1)
 166           {
 167             // This is an error condition but it isn't clear what we
 168             // should do with it.
 169             eof = true;
 170             return -1;
 171           }
 172         count += len;
 173         if (count == size)
 174           {
 175             // Read CRLF
 176             int c1 = in.read();
 177             int c2 = in.read();
 178             if (c1 == -1 || c2 == -1)
 179               {
 180                 // EOF before CRLF: bad, but ignore
 181                 eof = true;
 182                 return -1;
 183               }
 184             if (c1 != 0x0d || c2 != 0x0a)
 185               {
 186                 throw new ProtocolException("expecting CRLF: " + c1 + "," + c2);
 187               }
 188             meta = true;
 189           }
 190         return len;
 191       }
 192   }
 193
 194   /**
 195    * This method returns the number of bytes that can be read from
 196    * this stream before a read might block.  Even if the underlying
 197    * InputStream has data available past the end of the current chunk,
 198    * we have no way of knowing how large the next chunk header will
 199    * be. So we cannot report available data past the current chunk.
 200    *
 201    * @return The number of bytes that can be read before a read might
 202    * block
 203    *
 204    * @exception IOException If an error occurs
 205    */
 206   public int available() throws IOException
 207   {
 208     if (meta)
 209       return 0;
 210
 211     return Math.min(in.available(), size - count);
 212   }
 213
 214   /**
 215    * This method closes the ChunkedInputStream by closing the underlying
 216    * InputStream.
 217    *
 218    * @exception IOException If an error occurs
 219    */
 220   public void close() throws IOException
 221   {
 222     in.close();
 223   }
 224
 225 }
 226