1    
2    /* ====================================================================
3     * The Apache Software License, Version 1.1
4     *
5     * Copyright (c) 2002 The Apache Software Foundation.  All rights
6     * reserved.
7     *
8     * Redistribution and use in source and binary forms, with or without
9     * modification, are permitted provided that the following conditions
10    * are met:
11    *
12    * 1. Redistributions of source code must retain the above copyright
13    *    notice, this list of conditions and the following disclaimer.
14    *
15    * 2. Redistributions in binary form must reproduce the above copyright
16    *    notice, this list of conditions and the following disclaimer in
17    *    the documentation and/or other materials provided with the
18    *    distribution.
19    *
20    * 3. The end-user documentation included with the redistribution,
21    *    if any, must include the following acknowledgment:
22    *       "This product includes software developed by the
23    *        Apache Software Foundation (http://www.apache.org/)."
24    *    Alternately, this acknowledgment may appear in the software itself,
25    *    if and wherever such third-party acknowledgments normally appear.
26    *
27    * 4. The names "Apache" and "Apache Software Foundation" and
28    *    "Apache POI" must not be used to endorse or promote products
29    *    derived from this software without prior written permission. For
30    *    written permission, please contact apache@apache.org.
31    *
32    * 5. Products derived from this software may not be called "Apache",
33    *    "Apache POI", nor may "Apache" appear in their name, without
34    *    prior written permission of the Apache Software Foundation.
35    *
36    * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
37    * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
38    * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
39    * DISCLAIMED.  IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
40    * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
41    * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
42    * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
43    * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
44    * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
45    * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
46    * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
47    * SUCH DAMAGE.
48    * ====================================================================
49    *
50    * This software consists of voluntary contributions made by many
51    * individuals on behalf of the Apache Software Foundation.  For more
52    * information on the Apache Software Foundation, please see
53    * <http://www.apache.org/>.
54    */
55   
56   package org.apache.poi.poifs.filesystem;
57   
58   import java.io.*;
59   
60   import java.util.*;
61   
62   /**
63    * This class provides a wrapper over an OutputStream so that Document
64    * writers can't accidently go over their size limits
65    *
66    * @author Marc Johnson (mjohnson at apache dot org)
67    */
68   
69   public class DocumentOutputStream
70       extends OutputStream
71   {
72       private OutputStream stream;
73       private int          limit;
74       private int          written;
75   
76       /**
77        * Create a DocumentOutputStream
78        *
79        * @param stream the OutputStream to which the data is actually
80        *               read
81        * @param limit the maximum number of bytes that can be written
82        */
83   
84       DocumentOutputStream(final OutputStream stream, final int limit)
85       {
86           this.stream  = stream;
87           this.limit   = limit;
88           this.written = 0;
89       }
90   
91       /**
92        * Writes the specified byte to this output stream. The general
93        * contract for write is that one byte is written to the output
94        * stream. The byte to be written is the eight low-order bits of
95        * the argument b. The 24 high-order bits of b are ignored.
96        *
97        * @param b the byte.
98        * @exception IOException if an I/O error occurs. In particular,
99        *                        an IOException may be thrown if the
100       *                        output stream has been closed, or if the
101       *                        writer tries to write too much data.
102       */
103  
104      public void write(final int b)
105          throws IOException
106      {
107          limitCheck(1);
108          stream.write(b);
109      }
110  
111      /**
112       * Writes b.length bytes from the specified byte array
113       * to this output stream.
114       *
115       * @param b the data.
116       * @exception IOException if an I/O error occurs.
117       */
118  
119      public void write(final byte b[])
120          throws IOException
121      {
122          write(b, 0, b.length);
123      }
124  
125      /**
126       * Writes len bytes from the specified byte array starting at
127       * offset off to this output stream.  The general contract for
128       * write(b, off, len) is that some of the bytes in the array b are
129       * written to the output stream in order; element b[off] is the
130       * first byte written and b[off+len-1] is the last byte written by
131       * this operation.<p>
132       * If b is null, a NullPointerException is thrown.<p>
133       * If off is negative, or len is negative, or off+len is greater
134       * than the length of the array b, then an
135       * IndexOutOfBoundsException is thrown.
136       *
137       * @param b the data.
138       * @param off the start offset in the data.
139       * @param len the number of bytes to write.
140       * @exception IOException if an I/O error occurs. In particular,
141       *                        an IOException</code> is thrown if the
142       *                        output stream is closed or if the writer
143       *                        tries to write too many bytes.
144       */
145  
146      public void write(final byte b[], final int off, final int len)
147          throws IOException
148      {
149          limitCheck(len);
150          stream.write(b, off, len);
151      }
152  
153      /**
154       * Flushes this output stream and forces any buffered output bytes
155       * to be written out.
156       *
157       * @exception IOException if an I/O error occurs.
158       */
159  
160      public void flush()
161          throws IOException
162      {
163          stream.flush();
164      }
165  
166      /**
167       * Closes this output stream and releases any system resources
168       * associated with this stream. The general contract of close is
169       * that it closes the output stream. A closed stream cannot
170       * perform output operations and cannot be reopened.
171       *
172       * @exception IOException if an I/O error occurs.
173       */
174  
175      public void close()
176          throws IOException
177      {
178  
179          // ignore this call
180      }
181  
182      /**
183       * write the rest of the document's data (fill in at the end)
184       *
185       * @param totalLimit the actual number of bytes the corresponding
186       *                   document must fill
187       * @param fill the byte to fill remaining space with
188       *
189       * @exception IOException on I/O error
190       */
191  
192      void writeFiller(final int totalLimit, final byte fill)
193          throws IOException
194      {
195          if (totalLimit > written)
196          {
197              byte[] filler = new byte[ totalLimit - written ];
198  
199              Arrays.fill(filler, fill);
200              stream.write(filler);
201          }
202      }
203  
204      private void limitCheck(final int toBeWritten)
205          throws IOException
206      {
207          if ((written + toBeWritten) > limit)
208          {
209              throw new IOException("tried to write too much data");
210          }
211          written += toBeWritten;
212      }
213  }   // end public class DocumentOutputStream
214  
215