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: 
  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: }