Source for gnu.java.net.protocol.http.ChunkedInputStream

   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:   Headers headers;
  62: 
  63:   /** The underlying stream. */
  64:   private InputStream in;
  65: 
  66:   /** Size of the chunk we're reading.  */
  67:   int size;
  68:   /** Number of bytes we've read in this chunk.  */
  69:   int count;
  70:   /**
  71:    * True when we should read meta-information, false when we should
  72:    * read data.
  73:    */
  74:   boolean meta;
  75:   /** True when we've hit EOF.  */
  76:   boolean eof;
  77: 
  78:   /**
  79:    * Constructor.
  80:    * @param in the response socket input stream
  81:    * @param headers the headers to receive additional header lines
  82:    */
  83:   public ChunkedInputStream(InputStream in, Headers headers)
  84:   {
  85:     this.in = in;
  86:     this.headers = headers;
  87:     size = -1;
  88:     count = 0;
  89:     meta = true;
  90:   }
  91: 
  92:   public int read()
  93:     throws IOException
  94:   {
  95:     byte[] buf = new byte[1];
  96:     int len = read(buf, 0, 1);
  97:     if (len == -1)
  98:       {
  99:         return -1;
 100:       }
 101:     return 0xff & buf[0];
 102:   }
 103: 
 104:   public synchronized int read(byte[] buffer, int offset, int length)
 105:     throws IOException
 106:   {
 107:     if (eof)
 108:       {
 109:         return -1;
 110:       }
 111:     if (meta)
 112:       {
 113:         // Read chunk header
 114:         int c, last = 0;
 115:         boolean seenSemi = false;
 116:         StringBuilder buf = new StringBuilder();
 117:         do
 118:           {
 119:             c = in.read();
 120:             if (c == 0x3b) // ;
 121:               {
 122:                 seenSemi = true;
 123:               }
 124:             else if (c == 0x0a && last == 0x0d) // CRLF
 125:               {
 126:                 try
 127:                   {
 128:                     size = Integer.parseInt(buf.toString(), 16);
 129:                   }
 130:                 catch (NumberFormatException nfe)
 131:                   {
 132:                     IOException ioe = new IOException("Bad chunk header");
 133:                     ioe.initCause(nfe);
 134:                     // Unrecoverable.  Don't try to read more.
 135:                     in.close();
 136:                     throw ioe;
 137:                   }
 138:                 break;
 139:               }
 140:             else if (!seenSemi && c >= 0x30)
 141:               {
 142:                 buf.append ((char) c);
 143:               }
 144:             last = c;
 145:           }
 146:         while(c != -1);
 147:         count = 0;
 148:         meta = false;
 149:       }
 150:     if (size == 0)
 151:       {
 152:         // Read trailer
 153:         headers.parse(in);
 154:         eof = true;
 155:         return -1;
 156:       }
 157:     else
 158:       {
 159:     int canRead = Math.min(size - count, length);
 160:     int len = in.read(buffer, offset, canRead);
 161:     if (len == -1)
 162:       {
 163:         // This is an error condition but it isn't clear what we
 164:         // should do with it.
 165:         eof = true;
 166:         return -1;
 167:       }
 168:         count += len;
 169:         if (count == size)
 170:           {
 171:             // Read CRLF
 172:             int c1 = in.read();
 173:             int c2 = in.read();
 174:             if (c1 == -1 || c2 == -1)
 175:               {
 176:                 // EOF before CRLF: bad, but ignore
 177:                 eof = true;
 178:                 return -1;
 179:               }
 180:             if (c1 != 0x0d || c2 != 0x0a)
 181:               {
 182:                 throw new ProtocolException("expecting CRLF: " + c1 + "," + c2);
 183:               }
 184:             meta = true;
 185:           }
 186:         return len;
 187:       }
 188:   }
 189: 
 190:   /**
 191:    * This method returns the number of bytes that can be read from
 192:    * this stream before a read might block.  Even if the underlying
 193:    * InputStream has data available past the end of the current chunk,
 194:    * we have no way of knowing how large the next chunk header will
 195:    * be. So we cannot report available data past the current chunk.
 196:    *
 197:    * @return The number of bytes that can be read before a read might
 198:    * block
 199:    *
 200:    * @exception IOException If an error occurs
 201:    */
 202:   public int available() throws IOException
 203:   {
 204:     if (meta)
 205:       return 0;
 206:     
 207:     return Math.min(in.available(), size - count);
 208:   }
 209: 
 210:   /**
 211:    * This method closes the ChunkedInputStream by closing the underlying
 212:    * InputStream.
 213:    * 
 214:    * @exception IOException If an error occurs
 215:    */
 216:   public void close() throws IOException
 217:   {
 218:     in.close();
 219:   }
 220:   
 221: }