View Javadoc

1   //
2   //  ========================================================================
3   //  Copyright (c) 1995-2016 Mort Bay Consulting Pty. Ltd.
4   //  ------------------------------------------------------------------------
5   //  All rights reserved. This program and the accompanying materials
6   //  are made available under the terms of the Eclipse Public License v1.0
7   //  and Apache License v2.0 which accompanies this distribution.
8   //
9   //      The Eclipse Public License is available at
10  //      http://www.eclipse.org/legal/epl-v10.html
11  //
12  //      The Apache License v2.0 is available at
13  //      http://www.opensource.org/licenses/apache2.0.php
14  //
15  //  You may elect to redistribute this code under either of these licenses.
16  //  ========================================================================
17  //
18  
19  package org.eclipse.jetty.util;
20  
21  import java.io.BufferedInputStream;
22  import java.io.BufferedOutputStream;
23  import java.io.ByteArrayInputStream;
24  import java.io.ByteArrayOutputStream;
25  import java.io.File;
26  import java.io.FileInputStream;
27  import java.io.FileOutputStream;
28  import java.io.FilterInputStream;
29  import java.io.IOException;
30  import java.io.InputStream;
31  import java.io.OutputStream;
32  import java.nio.charset.StandardCharsets;
33  import java.nio.file.Files;
34  import java.nio.file.Path;
35  import java.nio.file.StandardCopyOption;
36  import java.util.ArrayList;
37  import java.util.Collection;
38  import java.util.Collections;
39  import java.util.List;
40  import java.util.Locale;
41  
42  import javax.servlet.MultipartConfigElement;
43  import javax.servlet.http.Part;
44  
45  import org.eclipse.jetty.util.log.Log;
46  import org.eclipse.jetty.util.log.Logger;
47  
48  
49  
50  /**
51   * MultiPartInputStream
52   *
53   * Handle a MultiPart Mime input stream, breaking it up on the boundary into files and strings.
54   */
55  public class MultiPartInputStreamParser
56  {
57      private static final Logger LOG = Log.getLogger(MultiPartInputStreamParser.class);
58      public static final MultipartConfigElement  __DEFAULT_MULTIPART_CONFIG = new MultipartConfigElement(System.getProperty("java.io.tmpdir"));
59      protected InputStream _in;
60      protected MultipartConfigElement _config;
61      protected String _contentType;
62      protected MultiMap<Part> _parts;
63      protected Exception _err;
64      protected File _tmpDir;
65      protected File _contextTmpDir;
66      protected boolean _deleteOnExit;
67      protected boolean _writeFilesWithFilenames;
68  
69  
70  
71      public class MultiPart implements Part
72      {
73          protected String _name;
74          protected String _filename;
75          protected File _file;
76          protected OutputStream _out;
77          protected ByteArrayOutputStream2 _bout;
78          protected String _contentType;
79          protected MultiMap<String> _headers;
80          protected long _size = 0;
81          protected boolean _temporary = true;
82  
83          public MultiPart (String name, String filename)
84          throws IOException
85          {
86              _name = name;
87              _filename = filename;
88          }
89  
90          protected void setContentType (String contentType)
91          {
92              _contentType = contentType;
93          }
94  
95  
96          protected void open()
97          throws IOException
98          {
99              //We will either be writing to a file, if it has a filename on the content-disposition
100             //and otherwise a byte-array-input-stream, OR if we exceed the getFileSizeThreshold, we
101             //will need to change to write to a file.
102             if (isWriteFilesWithFilenames() && _filename != null && _filename.trim().length() > 0)
103             {
104                 createFile();
105             }
106             else
107             {
108                 //Write to a buffer in memory until we discover we've exceed the
109                 //MultipartConfig fileSizeThreshold
110                 _out = _bout= new ByteArrayOutputStream2();
111             }
112         }
113 
114         protected void close()
115         throws IOException
116         {
117             _out.close();
118         }
119 
120 
121         protected void write (int b)
122         throws IOException
123         {
124             if (MultiPartInputStreamParser.this._config.getMaxFileSize() > 0 && _size + 1 > MultiPartInputStreamParser.this._config.getMaxFileSize())
125                 throw new IllegalStateException ("Multipart Mime part "+_name+" exceeds max filesize");
126 
127             if (MultiPartInputStreamParser.this._config.getFileSizeThreshold() > 0 && _size + 1 > MultiPartInputStreamParser.this._config.getFileSizeThreshold() && _file==null)
128                 createFile();
129 
130             _out.write(b);
131             _size ++;
132         }
133 
134         protected void write (byte[] bytes, int offset, int length)
135         throws IOException
136         {
137             if (MultiPartInputStreamParser.this._config.getMaxFileSize() > 0 && _size + length > MultiPartInputStreamParser.this._config.getMaxFileSize())
138                 throw new IllegalStateException ("Multipart Mime part "+_name+" exceeds max filesize");
139 
140             if (MultiPartInputStreamParser.this._config.getFileSizeThreshold() > 0 && _size + length > MultiPartInputStreamParser.this._config.getFileSizeThreshold() && _file==null)
141                 createFile();
142 
143             _out.write(bytes, offset, length);
144             _size += length;
145         }
146 
147         protected void createFile ()
148         throws IOException
149         {
150             _file = File.createTempFile("MultiPart", "", MultiPartInputStreamParser.this._tmpDir);
151 
152             if (_deleteOnExit)
153                 _file.deleteOnExit();
154             FileOutputStream fos = new FileOutputStream(_file);
155             BufferedOutputStream bos = new BufferedOutputStream(fos);
156 
157             if (_size > 0 && _out != null)
158             {
159                 //already written some bytes, so need to copy them into the file
160                 _out.flush();
161                 _bout.writeTo(bos);
162                 _out.close();
163                 _bout = null;
164             }
165             _out = bos;
166         }
167 
168 
169 
170         protected void setHeaders(MultiMap<String> headers)
171         {
172             _headers = headers;
173         }
174 
175         /**
176          * @see javax.servlet.http.Part#getContentType()
177          */
178         public String getContentType()
179         {
180             return _contentType;
181         }
182 
183         /**
184          * @see javax.servlet.http.Part#getHeader(java.lang.String)
185          */
186         public String getHeader(String name)
187         {
188             if (name == null)
189                 return null;
190             return _headers.getValue(name.toLowerCase(Locale.ENGLISH), 0);
191         }
192 
193         /**
194          * @see javax.servlet.http.Part#getHeaderNames()
195          */
196         public Collection<String> getHeaderNames()
197         {
198             return _headers.keySet();
199         }
200 
201         /**
202          * @see javax.servlet.http.Part#getHeaders(java.lang.String)
203          */
204         public Collection<String> getHeaders(String name)
205         {
206            return _headers.getValues(name);
207         }
208 
209         /**
210          * @see javax.servlet.http.Part#getInputStream()
211          */
212         public InputStream getInputStream() throws IOException
213         {
214            if (_file != null)
215            {
216                //written to a file, whether temporary or not
217                return new BufferedInputStream (new FileInputStream(_file));
218            }
219            else
220            {
221                //part content is in memory
222                return new ByteArrayInputStream(_bout.getBuf(),0,_bout.size());
223            }
224         }
225 
226 
227         /**
228          * @see javax.servlet.http.Part#getSubmittedFileName()
229          */
230         @Override
231         public String getSubmittedFileName()
232         {
233             return getContentDispositionFilename();
234         }
235 
236         public byte[] getBytes()
237         {
238             if (_bout!=null)
239                 return _bout.toByteArray();
240             return null;
241         }
242 
243         /**
244          * @see javax.servlet.http.Part#getName()
245          */
246         public String getName()
247         {
248            return _name;
249         }
250 
251         /**
252          * @see javax.servlet.http.Part#getSize()
253          */
254         public long getSize()
255         {
256             return _size;
257         }
258 
259         /**
260          * @see javax.servlet.http.Part#write(java.lang.String)
261          */
262         public void write(String fileName) throws IOException
263         {
264             if (_file == null)
265             {
266                 _temporary = false;
267 
268                 //part data is only in the ByteArrayOutputStream and never been written to disk
269                 _file = new File (_tmpDir, fileName);
270 
271                 BufferedOutputStream bos = null;
272                 try
273                 {
274                     bos = new BufferedOutputStream(new FileOutputStream(_file));
275                     _bout.writeTo(bos);
276                     bos.flush();
277                 }
278                 finally
279                 {
280                     if (bos != null)
281                         bos.close();
282                     _bout = null;
283                 }
284             }
285             else
286             {
287                 //the part data is already written to a temporary file, just rename it
288                 _temporary = false;
289 
290                 Path src = _file.toPath();
291                 Path target = src.resolveSibling(fileName);
292                 Files.move(src, target, StandardCopyOption.REPLACE_EXISTING);
293                 _file = target.toFile();
294             }
295         }
296 
297         /**
298          * Remove the file, whether or not Part.write() was called on it
299          * (ie no longer temporary)
300          * @see javax.servlet.http.Part#delete()
301          */
302         public void delete() throws IOException
303         {
304             if (_file != null && _file.exists())
305                 _file.delete();
306         }
307 
308         /**
309          * Only remove tmp files.
310          *
311          * @throws IOException if unable to delete the file
312          */
313         public void cleanUp() throws IOException
314         {
315             if (_temporary && _file != null && _file.exists())
316                 _file.delete();
317         }
318 
319 
320         /**
321          * Get the file
322          * @return the file, if any, the data has been written to.
323          */
324         public File getFile ()
325         {
326             return _file;
327         }
328 
329 
330         /**
331          * Get the filename from the content-disposition.
332          * @return null or the filename
333          */
334         public String getContentDispositionFilename ()
335         {
336             return _filename;
337         }
338     }
339 
340 
341 
342 
343     /**
344      * @param in Request input stream
345      * @param contentType Content-Type header
346      * @param config MultipartConfigElement
347      * @param contextTmpDir javax.servlet.context.tempdir
348      */
349     public MultiPartInputStreamParser (InputStream in, String contentType, MultipartConfigElement config, File contextTmpDir)
350     {
351         _in = new ReadLineInputStream(in);
352        _contentType = contentType;
353        _config = config;
354        _contextTmpDir = contextTmpDir;
355        if (_contextTmpDir == null)
356            _contextTmpDir = new File (System.getProperty("java.io.tmpdir"));
357 
358        if (_config == null)
359            _config = new MultipartConfigElement(_contextTmpDir.getAbsolutePath());
360     }
361 
362     /**
363      * Get the already parsed parts.
364      * @return the parts that were parsed
365      */
366     public Collection<Part> getParsedParts()
367     {
368         if (_parts == null)
369             return Collections.emptyList();
370 
371         Collection<List<Part>> values = _parts.values();
372         List<Part> parts = new ArrayList<>();
373         for (List<Part> o: values)
374         {
375             List<Part> asList = LazyList.getList(o, false);
376             parts.addAll(asList);
377         }
378         return parts;
379     }
380 
381     /**
382      * Delete any tmp storage for parts, and clear out the parts list.
383      *
384      * @throws MultiException if unable to delete the parts
385      */
386     public void deleteParts ()
387     throws MultiException
388     {
389         Collection<Part> parts = getParsedParts();
390         MultiException err = new MultiException();
391         for (Part p:parts)
392         {
393             try
394             {
395                 ((MultiPartInputStreamParser.MultiPart)p).cleanUp();
396             }
397             catch(Exception e)
398             {
399                 err.add(e);
400             }
401         }
402         _parts.clear();
403 
404         err.ifExceptionThrowMulti();
405     }
406 
407 
408     /**
409      * Parse, if necessary, the multipart data and return the list of Parts.
410      *
411      * @return the parts
412      * @throws IOException if unable to get the parts
413      */
414     public Collection<Part> getParts()
415     throws IOException
416     {
417         parse();
418         throwIfError();
419 
420         
421         Collection<List<Part>> values = _parts.values();
422         List<Part> parts = new ArrayList<>();
423         for (List<Part> o: values)
424         {
425             List<Part> asList = LazyList.getList(o, false);
426             parts.addAll(asList);
427         }
428         return parts;
429     }
430 
431 
432     /**
433      * Get the named Part.
434      *
435      * @param name the part name
436      * @return the parts
437      * @throws IOException if unable to get the part
438      */
439     public Part getPart(String name)
440     throws IOException
441     {
442         parse();
443         throwIfError();   
444         return _parts.getValue(name, 0);
445     }
446 
447     /**
448      * Throws an exception if one has been latched.
449      * 
450      * @throws IOException
451      */
452     protected void throwIfError ()
453     throws IOException
454     {
455         if (_err != null)
456         {
457             if (_err instanceof IOException)
458                 throw (IOException)_err;
459             if (_err instanceof IllegalStateException)
460                 throw (IllegalStateException)_err;
461             throw new IllegalStateException(_err);
462         }
463     }
464 
465     /**
466      * Parse, if necessary, the multipart stream.
467      *
468      */
469     protected void parse ()
470     {
471         //have we already parsed the input?
472         if (_parts != null || _err != null)
473             return;
474 
475         //initialize
476         long total = 0; //keep running total of size of bytes read from input and throw an exception if exceeds MultipartConfigElement._maxRequestSize
477         _parts = new MultiMap<>();
478 
479         //if its not a multipart request, don't parse it
480         if (_contentType == null || !_contentType.startsWith("multipart/form-data"))
481             return;
482 
483         try
484         {
485             //sort out the location to which to write the files
486 
487             if (_config.getLocation() == null)
488                 _tmpDir = _contextTmpDir;
489             else if ("".equals(_config.getLocation()))
490                 _tmpDir = _contextTmpDir;
491             else
492             {
493                 File f = new File (_config.getLocation());
494                 if (f.isAbsolute())
495                     _tmpDir = f;
496                 else
497                     _tmpDir = new File (_contextTmpDir, _config.getLocation());
498             }
499 
500             if (!_tmpDir.exists())
501                 _tmpDir.mkdirs();
502 
503             String contentTypeBoundary = "";
504             int bstart = _contentType.indexOf("boundary=");
505             if (bstart >= 0)
506             {
507                 int bend = _contentType.indexOf(";", bstart);
508                 bend = (bend < 0? _contentType.length(): bend);
509                 contentTypeBoundary = QuotedStringTokenizer.unquote(value(_contentType.substring(bstart,bend)).trim());
510             }
511 
512             String boundary="--"+contentTypeBoundary;
513             String lastBoundary=boundary+"--";
514             byte[] byteBoundary=lastBoundary.getBytes(StandardCharsets.ISO_8859_1);
515 
516             // Get first boundary
517             String line = null;
518             try
519             {
520                 line=((ReadLineInputStream)_in).readLine();
521             }
522             catch (IOException e)
523             {
524                 LOG.warn("Badly formatted multipart request");
525                 throw e;
526             }
527 
528             if (line == null)
529                 throw new IOException("Missing content for multipart request");
530 
531             boolean badFormatLogged = false;
532             line=line.trim();
533             while (line != null && !line.equals(boundary) && !line.equals(lastBoundary))
534             {
535                 if (!badFormatLogged)
536                 {
537                     LOG.warn("Badly formatted multipart request");
538                     badFormatLogged = true;
539                 }
540                 line=((ReadLineInputStream)_in).readLine();
541                 line=(line==null?line:line.trim());
542             }
543 
544             if (line == null)
545                 throw new IOException("Missing initial multi part boundary");
546 
547             // Empty multipart.
548             if (line.equals(lastBoundary))
549                 return;
550 
551             // Read each part
552             boolean lastPart=false;
553 
554             outer:while(!lastPart)
555             {
556                 String contentDisposition=null;
557                 String contentType=null;
558                 String contentTransferEncoding=null;
559 
560                 MultiMap<String> headers = new MultiMap<>();
561                 while(true)
562                 {
563                     line=((ReadLineInputStream)_in).readLine();
564 
565                     //No more input
566                     if(line==null)
567                         break outer;
568 
569                     //end of headers:
570                     if("".equals(line))
571                         break;
572 
573                     total += line.length();
574                     if (_config.getMaxRequestSize() > 0 && total > _config.getMaxRequestSize())
575                         throw new IllegalStateException ("Request exceeds maxRequestSize ("+_config.getMaxRequestSize()+")");
576 
577                     //get content-disposition and content-type
578                     int c=line.indexOf(':',0);
579                     if(c>0)
580                     {
581                         String key=line.substring(0,c).trim().toLowerCase(Locale.ENGLISH);
582                         String value=line.substring(c+1,line.length()).trim();
583                         headers.put(key, value);
584                         if (key.equalsIgnoreCase("content-disposition"))
585                             contentDisposition=value;
586                         if (key.equalsIgnoreCase("content-type"))
587                             contentType = value;
588                         if(key.equals("content-transfer-encoding"))
589                             contentTransferEncoding=value;
590                     }
591                 }
592 
593                 // Extract content-disposition
594                 boolean form_data=false;
595                 if(contentDisposition==null)
596                 {
597                     throw new IOException("Missing content-disposition");
598                 }
599 
600                 QuotedStringTokenizer tok=new QuotedStringTokenizer(contentDisposition,";", false, true);
601                 String name=null;
602                 String filename=null;
603                 while(tok.hasMoreTokens())
604                 {
605                     String t=tok.nextToken().trim();
606                     String tl=t.toLowerCase(Locale.ENGLISH);
607                     if(t.startsWith("form-data"))
608                         form_data=true;
609                     else if(tl.startsWith("name="))
610                         name=value(t);
611                     else if(tl.startsWith("filename="))
612                         filename=filenameValue(t);
613                 }
614 
615                 // Check disposition
616                 if(!form_data)
617                 {
618                     continue;
619                 }
620                 //It is valid for reset and submit buttons to have an empty name.
621                 //If no name is supplied, the browser skips sending the info for that field.
622                 //However, if you supply the empty string as the name, the browser sends the
623                 //field, with name as the empty string. So, only continue this loop if we
624                 //have not yet seen a name field.
625                 if(name==null)
626                 {
627                     continue;
628                 }
629 
630                 //Have a new Part
631                 MultiPart part = new MultiPart(name, filename);
632                 part.setHeaders(headers);
633                 part.setContentType(contentType);
634                 _parts.add(name, part);
635                 part.open();
636 
637                 InputStream partInput = null;
638                 if ("base64".equalsIgnoreCase(contentTransferEncoding))
639                 {
640                     partInput = new Base64InputStream((ReadLineInputStream)_in);
641                 }
642                 else if ("quoted-printable".equalsIgnoreCase(contentTransferEncoding))
643                 {
644                     partInput = new FilterInputStream(_in)
645                     {
646                         @Override
647                         public int read() throws IOException
648                         {
649                             int c = in.read();
650                             if (c >= 0 && c == '=')
651                             {
652                                 int hi = in.read();
653                                 int lo = in.read();
654                                 if (hi < 0 || lo < 0)
655                                 {
656                                     throw new IOException("Unexpected end to quoted-printable byte");
657                                 }
658                                 char[] chars = new char[] { (char)hi, (char)lo };
659                                 c = Integer.parseInt(new String(chars),16);
660                             }
661                             return c;
662                         }
663                     };
664                 }
665                 else
666                     partInput = _in;
667 
668 
669                 try
670                 {
671                     int state=-2;
672                     int c;
673                     boolean cr=false;
674                     boolean lf=false;
675 
676                     // loop for all lines
677                     while(true)
678                     {
679                         int b=0;
680                         while((c=(state!=-2)?state:partInput.read())!=-1)
681                         {
682                             total ++;
683                             if (_config.getMaxRequestSize() > 0 && total > _config.getMaxRequestSize())
684                                 throw new IllegalStateException("Request exceeds maxRequestSize ("+_config.getMaxRequestSize()+")");
685 
686                             state=-2;
687 
688                             // look for CR and/or LF
689                             if(c==13||c==10)
690                             {
691                                 if(c==13)
692                                 {
693                                     partInput.mark(1);
694                                     int tmp=partInput.read();
695                                     if (tmp!=10)
696                                         partInput.reset();
697                                     else
698                                         state=tmp;
699                                 }
700                                 break;
701                             }
702 
703                             // Look for boundary
704                             if(b>=0&&b<byteBoundary.length&&c==byteBoundary[b])
705                             {
706                                 b++;
707                             }
708                             else
709                             {
710                                 // Got a character not part of the boundary, so we don't have the boundary marker.
711                                 // Write out as many chars as we matched, then the char we're looking at.
712                                 if(cr)
713                                     part.write(13);
714 
715                                 if(lf)
716                                     part.write(10);
717 
718                                 cr=lf=false;
719                                 if(b>0)
720                                     part.write(byteBoundary,0,b);
721 
722                                 b=-1;
723                                 part.write(c);
724                             }
725                         }
726 
727                         // Check for incomplete boundary match, writing out the chars we matched along the way
728                         if((b>0&&b<byteBoundary.length-2)||(b==byteBoundary.length-1))
729                         {
730                             if(cr)
731                                 part.write(13);
732 
733                             if(lf)
734                                 part.write(10);
735 
736                             cr=lf=false;
737                             part.write(byteBoundary,0,b);
738                             b=-1;
739                         }
740 
741                         // Boundary match. If we've run out of input or we matched the entire final boundary marker, then this is the last part.
742                         if(b>0||c==-1)
743                         {
744 
745                             if(b==byteBoundary.length)
746                                 lastPart=true;
747                             if(state==10)
748                                 state=-2;
749                             break;
750                         }
751 
752                         // handle CR LF
753                         if(cr)
754                             part.write(13);
755 
756                         if(lf)
757                             part.write(10);
758 
759                         cr=(c==13);
760                         lf=(c==10||state==10);
761                         if(state==10)
762                             state=-2;
763                     }
764                 }
765                 finally
766                 {
767                     part.close();
768                 }
769             }
770             if (lastPart)
771             {
772                 while(line!=null)
773                     line=((ReadLineInputStream)_in).readLine();
774             }
775             else
776                 throw new IOException("Incomplete parts");
777         }
778         catch (Exception e)
779         {
780             _err = e;
781         }
782     }
783 
784     public void setDeleteOnExit(boolean deleteOnExit)
785     {
786         _deleteOnExit = deleteOnExit;
787     }
788 
789     public void setWriteFilesWithFilenames (boolean writeFilesWithFilenames)
790     {
791         _writeFilesWithFilenames = writeFilesWithFilenames;
792     }
793     
794     public boolean isWriteFilesWithFilenames ()
795     {
796         return _writeFilesWithFilenames;
797     }
798 
799     public boolean isDeleteOnExit()
800     {
801         return _deleteOnExit;
802     }
803 
804 
805     /* ------------------------------------------------------------ */
806     private String value(String nameEqualsValue)
807     {
808         int idx = nameEqualsValue.indexOf('=');
809         String value = nameEqualsValue.substring(idx+1).trim();
810         return QuotedStringTokenizer.unquoteOnly(value);
811     }
812 
813 
814     /* ------------------------------------------------------------ */
815     private String filenameValue(String nameEqualsValue)
816     {
817         int idx = nameEqualsValue.indexOf('=');
818         String value = nameEqualsValue.substring(idx+1).trim();
819 
820         if (value.matches(".??[a-z,A-Z]\\:\\\\[^\\\\].*"))
821         {
822             //incorrectly escaped IE filenames that have the whole path
823             //we just strip any leading & trailing quotes and leave it as is
824             char first=value.charAt(0);
825             if (first=='"' || first=='\'')
826                 value=value.substring(1);
827             char last=value.charAt(value.length()-1);
828             if (last=='"' || last=='\'')
829                 value = value.substring(0,value.length()-1);
830 
831             return value;
832         }
833         else
834             //unquote the string, but allow any backslashes that don't
835             //form a valid escape sequence to remain as many browsers
836             //even on *nix systems will not escape a filename containing
837             //backslashes
838             return QuotedStringTokenizer.unquoteOnly(value, true);
839     }
840 
841 
842 
843     private static class Base64InputStream extends InputStream
844     {
845         ReadLineInputStream _in;
846         String _line;
847         byte[] _buffer;
848         int _pos;
849 
850 
851         public Base64InputStream(ReadLineInputStream rlis)
852         {
853             _in = rlis;
854         }
855 
856         @Override
857         public int read() throws IOException
858         {
859             if (_buffer==null || _pos>= _buffer.length)
860             {
861                 //Any CR and LF will be consumed by the readLine() call.
862                 //We need to put them back into the bytes returned from this
863                 //method because the parsing of the multipart content uses them
864                 //as markers to determine when we've reached the end of a part.
865                 _line = _in.readLine();
866                 if (_line==null)
867                     return -1;  //nothing left
868                 if (_line.startsWith("--"))
869                     _buffer=(_line+"\r\n").getBytes(); //boundary marking end of part
870                 else if (_line.length()==0)
871                     _buffer="\r\n".getBytes(); //blank line
872                 else
873                 {
874                     ByteArrayOutputStream baos = new ByteArrayOutputStream((4*_line.length()/3)+2);
875                     B64Code.decode(_line, baos);
876                     baos.write(13);
877                     baos.write(10);
878                     _buffer = baos.toByteArray();
879                 }
880 
881                 _pos=0;
882             }
883 
884             return _buffer[_pos++];
885         }
886     }
887 }