001/* BufferedReader.java
002   Copyright (C) 1998, 1999, 2000, 2001, 2003, 2005
003   Free Software Foundation, Inc.
004
005This file is part of GNU Classpath.
006
007GNU Classpath is free software; you can redistribute it and/or modify
008it under the terms of the GNU General Public License as published by
009the Free Software Foundation; either version 2, or (at your option)
010any later version.
011 
012GNU Classpath is distributed in the hope that it will be useful, but
013WITHOUT ANY WARRANTY; without even the implied warranty of
014MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
015General Public License for more details.
016
017You should have received a copy of the GNU General Public License
018along with GNU Classpath; see the file COPYING.  If not, write to the
019Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
02002110-1301 USA.
021
022Linking this library statically or dynamically with other modules is
023making a combined work based on this library.  Thus, the terms and
024conditions of the GNU General Public License cover the whole
025combination.
026
027As a special exception, the copyright holders of this library give you
028permission to link this library with independent modules to produce an
029executable, regardless of the license terms of these independent
030modules, and to copy and distribute the resulting executable under
031terms of your choice, provided that you also meet, for each linked
032independent module, the terms and conditions of the license of that
033module.  An independent module is a module which is not derived from
034or based on this library.  If you modify this library, you may extend
035this exception to your version of the library, but you are not
036obligated to do so.  If you do not wish to do so, delete this
037exception statement from your version. */
038
039
040package java.io;
041
042/* Written using "Java Class Libraries", 2nd edition, ISBN 0-201-31002-3
043 * "The Java Language Specification", ISBN 0-201-63451-1
044 * Status:  Complete to version 1.1.
045 */
046
047/**
048  * This class allows data to be written to a byte array buffer and
049  * and then retrieved by an application.   The internal byte array
050  * buffer is dynamically resized to hold all the data written.  Please
051  * be aware that writing large amounts to data to this stream will
052  * cause large amounts of memory to be allocated.
053  * <p>
054  * The size of the internal buffer defaults to 32 and it is resized
055  * by doubling the size of the buffer.  This default size can be
056  * overridden by using the
057  * <code>gnu.java.io.ByteArrayOutputStream.initialBufferSize</code>
058  * property.
059  * <p>
060  * There is a constructor that specified the initial buffer size and
061  * that is the preferred way to set that value because it it portable
062  * across all Java class library implementations.
063  * <p>
064  * Note that this class also has methods that convert the byte array
065  * buffer to a <code>String</code> using either the system default or an
066  * application specified character encoding.  Thus it can handle 
067  * multibyte character encodings.
068  *
069  * @author Aaron M. Renn (arenn@urbanophile.com)
070  * @author Tom Tromey (tromey@cygnus.com)
071  * @date September 24, 1998 
072  */
073public class ByteArrayOutputStream extends OutputStream
074{
075  /**
076   * This method initializes a new <code>ByteArrayOutputStream</code>
077   * with the default buffer size of 32 bytes.  If a different initial
078   * buffer size is desired, see the constructor
079   * <code>ByteArrayOutputStream(int size)</code>.  For applications
080   * where the source code is not available, the default buffer size
081   * can be set using the system property
082   * <code>gnu.java.io.ByteArrayOutputStream.initialBufferSize</code>
083   */
084  public ByteArrayOutputStream ()
085  {
086    this (initial_buffer_size);
087  }
088
089  /**
090   * This method initializes a new <code>ByteArrayOutputStream</code> with
091   * a specified initial buffer size.
092   *
093   * @param size The initial buffer size in bytes
094   */
095  public ByteArrayOutputStream (int size)
096  {
097    buf = new byte[size];
098    count = 0;
099  }
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   */
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   */
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   */
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   */
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   */
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   */
194  public String toString (int hibyte)
195  {
196    return new String (buf, hibyte, 0, count);
197  }
198
199  // Resize buffer to accommodate new bytes.
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   */
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   */
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   */
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}