1 /* BufferedReader.java
2    Copyright (C) 1998, 1999, 2000, 2001, 2003, 2005
3    Free Software Foundation, Inc.
4 
5 This file is part of GNU Classpath.
6 
7 GNU Classpath is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 2, or (at your option)
10 any later version.
11 
12 GNU Classpath is distributed in the hope that it will be useful, but
13 WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
15 General Public License for more details.
16 
17 You should have received a copy of the GNU General Public License
18 along with GNU Classpath; see the file COPYING.  If not, write to the
19 Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
20 02110-1301 USA.
21 
22 Linking this library statically or dynamically with other modules is
23 making a combined work based on this library.  Thus, the terms and
24 conditions of the GNU General Public License cover the whole
25 combination.
26 
27 As a special exception, the copyright holders of this library give you
28 permission to link this library with independent modules to produce an
29 executable, regardless of the license terms of these independent
30 modules, and to copy and distribute the resulting executable under
31 terms of your choice, provided that you also meet, for each linked
32 independent module, the terms and conditions of the license of that
33 module.  An independent module is a module which is not derived from
34 or based on this library.  If you modify this library, you may extend
35 this exception to your version of the library, but you are not
36 obligated to do so.  If you do not wish to do so, delete this
37 exception statement from your version. */
38 
39 
40 package java.io;
41 
42 /* Written using "Java Class Libraries", 2nd edition, ISBN 0-201-31002-3
43  * "The Java Language Specification", ISBN 0-201-63451-1
44  * Status:  Complete to version 1.1.
45  */
46 
47 /**
48   * This class allows data to be written to a byte array buffer and
49   * and then retrieved by an application.   The internal byte array
50   * buffer is dynamically resized to hold all the data written.  Please
51   * be aware that writing large amounts to data to this stream will
52   * cause large amounts of memory to be allocated.
53   * <p>
54   * The size of the internal buffer defaults to 32 and it is resized
55   * by doubling the size of the buffer.  This default size can be
56   * overridden by using the
57   * <code>gnu.java.io.ByteArrayOutputStream.initialBufferSize</code>
58   * property.
59   * <p>
60   * There is a constructor that specified the initial buffer size and
61   * that is the preferred way to set that value because it it portable
62   * across all Java class library implementations.
63   * <p>
64   * Note that this class also has methods that convert the byte array
65   * buffer to a <code>String</code> using either the system default or an
66   * application specified character encoding.  Thus it can handle
67   * multibyte character encodings.
68   *
69   * @author Aaron M. Renn (arenn@urbanophile.com)
70   * @author Tom Tromey (tromey@cygnus.com)
71   * @date September 24, 1998
72   */
73 public class ByteArrayOutputStream extends OutputStream
74 {
75   /**
76    * This method initializes a new <code>ByteArrayOutputStream</code>
77    * with the default buffer size of 32 bytes.  If a different initial
78    * buffer size is desired, see the constructor
79    * <code>ByteArrayOutputStream(int size)</code>.  For applications
80    * where the source code is not available, the default buffer size
81    * can be set using the system property
82    * <code>gnu.java.io.ByteArrayOutputStream.initialBufferSize</code>
83    */
ByteArrayOutputStream()84   public ByteArrayOutputStream ()
85   {
86     this (initial_buffer_size);
87   }
88 
89   /**
90    * This method initializes a new <code>ByteArrayOutputStream</code> with
91    * a specified initial buffer size.
92    *
93    * @param size The initial buffer size in bytes
94    */
ByteArrayOutputStream(int size)95   public ByteArrayOutputStream (int size)
96   {
97     buf = new byte[size];
98     count = 0;
99   }
100 
101   /**
102    * This method discards all of the bytes that have been written to
103    * the internal buffer so far by setting the <code>count</code>
104    * variable to 0.  The internal buffer remains at its currently
105    * allocated size.
106    */
reset()107   public synchronized void reset ()
108   {
109     count = 0;
110   }
111 
112   /**
113    * This method returns the number of bytes that have been written to
114    * the buffer so far.  This is the same as the value of the protected
115    * <code>count</code> variable.  If the <code>reset</code> method is
116    * called, then this value is reset as well.  Note that this method does
117    * not return the length of the internal buffer, but only the number
118    * of bytes that have been written to it.
119    *
120    * @return The number of bytes in the internal buffer
121    *
122    * @see #reset()
123    */
size()124   public int size ()
125   {
126     return count;
127   }
128 
129   /**
130    * This method returns a byte array containing the bytes that have been
131    * written to this stream so far.  This array is a copy of the valid
132    * bytes in the internal buffer and its length is equal to the number of
133    * valid bytes, not necessarily to the the length of the current
134    * internal buffer.  Note that since this method allocates a new array,
135    * it should be used with caution when the internal buffer is very large.
136    */
toByteArray()137   public synchronized byte[] toByteArray ()
138   {
139     byte[] ret = new byte[count];
140     System.arraycopy(buf, 0, ret, 0, count);
141     return ret;
142   }
143 
144   /**
145    * Returns the bytes in the internal array as a <code>String</code>.  The
146    * bytes in the buffer are converted to characters using the system default
147    * encoding.  There is an overloaded <code>toString()</code> method that
148    * allows an application specified character encoding to be used.
149    *
150    * @return A <code>String</code> containing the data written to this
151    * stream so far
152    */
toString()153   public String toString ()
154   {
155     return new String (buf, 0, count);
156   }
157 
158   /**
159    * Returns the bytes in the internal array as a <code>String</code>.  The
160    * bytes in the buffer are converted to characters using the specified
161    * encoding.
162    *
163    * @param enc The name of the character encoding to use
164    *
165    * @return A <code>String</code> containing the data written to this
166    * stream so far
167    *
168    * @exception UnsupportedEncodingException If the named encoding is
169    * not available
170    */
toString(String enc)171   public String toString (String enc) throws UnsupportedEncodingException
172   {
173     return new String (buf, 0, count, enc);
174   }
175 
176   /**
177    * This method returns the bytes in the internal array as a
178    * <code>String</code>.  It uses each byte in the array as the low
179    * order eight bits of the Unicode character value and the passed in
180    * parameter as the high eight bits.
181    * <p>
182    * This method does not convert bytes to characters in the proper way and
183    * so is deprecated in favor of the other overloaded <code>toString</code>
184    * methods which use a true character encoding.
185    *
186    * @param hibyte The high eight bits to use for each character in
187    * the <code>String</code>
188    *
189    * @return A <code>String</code> containing the data written to this
190    * stream so far
191    *
192    * @deprecated
193    */
toString(int hibyte)194   public String toString (int hibyte)
195   {
196     return new String (buf, hibyte, 0, count);
197   }
198 
199   // Resize buffer to accommodate new bytes.
resize(int add)200   private void resize (int add)
201   {
202     if (count + add > buf.length)
203       {
204         int newlen = buf.length * 2;
205         if (count + add > newlen)
206           newlen = count + add;
207         byte[] newbuf = new byte[newlen];
208         System.arraycopy(buf, 0, newbuf, 0, count);
209         buf = newbuf;
210       }
211   }
212 
213   /**
214    * This method writes the writes the specified byte into the internal
215    * buffer.
216    *
217    * @param oneByte The byte to be read passed as an int
218    */
write(int oneByte)219   public synchronized void write (int oneByte)
220   {
221     resize (1);
222     buf[count++] = (byte) oneByte;
223   }
224 
225   /**
226    * This method writes <code>len</code> bytes from the passed in array
227    * <code>buf</code> starting at index <code>offset</code> into the
228    * internal buffer.
229    *
230    * @param buffer The byte array to write data from
231    * @param offset The index into the buffer to start writing data from
232    * @param add The number of bytes to write
233    */
write(byte[] buffer, int offset, int add)234   public synchronized void write (byte[] buffer, int offset, int add)
235   {
236     // If ADD < 0 then arraycopy will throw the appropriate error for
237     // us.
238     if (add >= 0)
239       resize (add);
240     System.arraycopy(buffer, offset, buf, count, add);
241     count += add;
242   }
243 
244   /**
245    * This method writes all the bytes that have been written to this stream
246    * from the internal buffer to the specified <code>OutputStream</code>.
247    *
248    * @param out The <code>OutputStream</code> to write to
249    *
250    * @exception IOException If an error occurs
251    */
writeTo(OutputStream out)252   public synchronized void writeTo (OutputStream out) throws IOException
253   {
254     out.write(buf, 0, count);
255   }
256 
257   /**
258    * The internal buffer where the data written is stored
259    */
260   protected byte[] buf;
261 
262   /**
263    * The number of bytes that have been written to the buffer
264    */
265   protected int count;
266 
267   /**
268    * The default initial buffer size.  Specified by the JCL.
269    */
270   private static final int DEFAULT_INITIAL_BUFFER_SIZE = 32;
271 
272   // The default buffer size which can be overridden by the user.
273   private static final int initial_buffer_size;
274 
275   static
276   {
277     int r
278       = Integer.getInteger ("gnu.java.io.ByteArrayOutputStream.initialBufferSize",
279                             DEFAULT_INITIAL_BUFFER_SIZE).intValue ();
280     if (r <= 0)
281       r = DEFAULT_INITIAL_BUFFER_SIZE;
282     initial_buffer_size = r;
283   }
284 }
285