284 lines
9.3 KiB
Java
284 lines
9.3 KiB
Java
/* BufferedReader.java
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Copyright (C) 1998, 1999, 2000, 2001, 2003, 2005 Free Software Foundation, Inc.
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This file is part of GNU Classpath.
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GNU Classpath is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2, or (at your option)
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any later version.
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GNU Classpath is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with GNU Classpath; see the file COPYING. If not, write to the
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Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
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02110-1301 USA.
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Linking this library statically or dynamically with other modules is
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making a combined work based on this library. Thus, the terms and
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conditions of the GNU General Public License cover the whole
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combination.
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As a special exception, the copyright holders of this library give you
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permission to link this library with independent modules to produce an
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executable, regardless of the license terms of these independent
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modules, and to copy and distribute the resulting executable under
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terms of your choice, provided that you also meet, for each linked
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independent module, the terms and conditions of the license of that
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module. An independent module is a module which is not derived from
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or based on this library. If you modify this library, you may extend
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this exception to your version of the library, but you are not
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obligated to do so. If you do not wish to do so, delete this
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exception statement from your version. */
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package java.io;
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/* Written using "Java Class Libraries", 2nd edition, ISBN 0-201-31002-3
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* "The Java Language Specification", ISBN 0-201-63451-1
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* Status: Complete to version 1.1.
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*/
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/**
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* This class allows data to be written to a byte array buffer and
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* and then retrieved by an application. The internal byte array
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* buffer is dynamically resized to hold all the data written. Please
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* be aware that writing large amounts to data to this stream will
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* cause large amounts of memory to be allocated.
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* <p>
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* The size of the internal buffer defaults to 32 and it is resized
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* by doubling the size of the buffer. This default size can be
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* overridden by using the
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* <code>gnu.java.io.ByteArrayOutputStream.initialBufferSize</code>
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* property.
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* <p>
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* There is a constructor that specified the initial buffer size and
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* that is the preferred way to set that value because it it portable
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* across all Java class library implementations.
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* <p>
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* Note that this class also has methods that convert the byte array
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* buffer to a <code>String</code> using either the system default or an
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* application specified character encoding. Thus it can handle
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* multibyte character encodings.
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*
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* @author Aaron M. Renn (arenn@urbanophile.com)
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* @author Tom Tromey (tromey@cygnus.com)
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* @date September 24, 1998
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*/
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public class ByteArrayOutputStream extends OutputStream
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{
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/**
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* This method initializes a new <code>ByteArrayOutputStream</code>
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* with the default buffer size of 32 bytes. If a different initial
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* buffer size is desired, see the constructor
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* <code>ByteArrayOutputStream(int size)</code>. For applications
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* where the source code is not available, the default buffer size
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* can be set using the system property
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* <code>gnu.java.io.ByteArrayOutputStream.initialBufferSize</code>
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*/
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public ByteArrayOutputStream ()
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{
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this (initial_buffer_size);
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}
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/**
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* This method initializes a new <code>ByteArrayOutputStream</code> with
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* a specified initial buffer size.
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*
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* @param size The initial buffer size in bytes
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*/
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public ByteArrayOutputStream (int size)
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{
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buf = new byte[size];
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count = 0;
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}
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/**
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* This method discards all of the bytes that have been written to
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* the internal buffer so far by setting the <code>count</code>
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* variable to 0. The internal buffer remains at its currently
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* allocated size.
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*/
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public synchronized void reset ()
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{
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count = 0;
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}
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/**
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* This method returns the number of bytes that have been written to
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* the buffer so far. This is the same as the value of the protected
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* <code>count</code> variable. If the <code>reset</code> method is
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* called, then this value is reset as well. Note that this method does
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* not return the length of the internal buffer, but only the number
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* of bytes that have been written to it.
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*
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* @return The number of bytes in the internal buffer
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*
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* @see #reset()
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*/
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public int size ()
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{
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return count;
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}
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/**
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* This method returns a byte array containing the bytes that have been
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* written to this stream so far. This array is a copy of the valid
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* bytes in the internal buffer and its length is equal to the number of
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* valid bytes, not necessarily to the the length of the current
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* internal buffer. Note that since this method allocates a new array,
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* it should be used with caution when the internal buffer is very large.
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*/
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public synchronized byte[] toByteArray ()
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{
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byte[] ret = new byte[count];
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System.arraycopy(buf, 0, ret, 0, count);
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return ret;
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}
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/**
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* Returns the bytes in the internal array as a <code>String</code>. The
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* bytes in the buffer are converted to characters using the system default
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* encoding. There is an overloaded <code>toString()</code> method that
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* allows an application specified character encoding to be used.
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*
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* @return A <code>String</code> containing the data written to this
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* stream so far
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*/
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public String toString ()
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{
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return new String (buf, 0, count);
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}
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/**
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* Returns the bytes in the internal array as a <code>String</code>. The
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* bytes in the buffer are converted to characters using the specified
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* encoding.
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*
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* @param enc The name of the character encoding to use
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*
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* @return A <code>String</code> containing the data written to this
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* stream so far
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*
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* @exception UnsupportedEncodingException If the named encoding is
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* not available
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*/
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public String toString (String enc) throws UnsupportedEncodingException
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{
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return new String (buf, 0, count, enc);
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}
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/**
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* This method returns the bytes in the internal array as a
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* <code>String</code>. It uses each byte in the array as the low
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* order eight bits of the Unicode character value and the passed in
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* parameter as the high eight bits.
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* <p>
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* This method does not convert bytes to characters in the proper way and
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* so is deprecated in favor of the other overloaded <code>toString</code>
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* methods which use a true character encoding.
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*
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* @param hibyte The high eight bits to use for each character in
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* the <code>String</code>
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*
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* @return A <code>String</code> containing the data written to this
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* stream so far
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*
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* @deprecated
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*/
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public String toString (int hibyte)
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{
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return new String (buf, 0, count, hibyte);
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}
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// Resize buffer to accommodate new bytes.
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private void resize (int add)
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{
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if (count + add > buf.length)
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{
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int newlen = buf.length * 2;
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if (count + add > newlen)
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newlen = count + add;
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byte[] newbuf = new byte[newlen];
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System.arraycopy(buf, 0, newbuf, 0, count);
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buf = newbuf;
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}
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}
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/**
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* This method writes the writes the specified byte into the internal
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* buffer.
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*
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* @param oneByte The byte to be read passed as an int
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*/
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public synchronized void write (int oneByte)
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{
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resize (1);
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buf[count++] = (byte) oneByte;
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}
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/**
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* This method writes <code>len</code> bytes from the passed in array
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* <code>buf</code> starting at index <code>offset</code> into the
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* internal buffer.
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*
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* @param buffer The byte array to write data from
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* @param offset The index into the buffer to start writing data from
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* @param add The number of bytes to write
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*/
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public synchronized void write (byte[] buffer, int offset, int add)
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{
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// If ADD < 0 then arraycopy will throw the appropriate error for
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// us.
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if (add >= 0)
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resize (add);
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System.arraycopy(buffer, offset, buf, count, add);
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count += add;
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}
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/**
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* This method writes all the bytes that have been written to this stream
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* from the internal buffer to the specified <code>OutputStream</code>.
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*
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* @param out The <code>OutputStream</code> to write to
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*
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* @exception IOException If an error occurs
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*/
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public synchronized void writeTo (OutputStream out) throws IOException
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{
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out.write(buf, 0, count);
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}
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/**
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* The internal buffer where the data written is stored
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*/
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protected byte[] buf;
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/**
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* The number of bytes that have been written to the buffer
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*/
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protected int count;
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/**
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* The default initial buffer size. Specified by the JCL.
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*/
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private static final int DEFAULT_INITIAL_BUFFER_SIZE = 32;
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// The default buffer size which can be overridden by the user.
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private static final int initial_buffer_size;
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static
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{
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int r
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= Integer.getInteger ("gnu.java.io.ByteArrayOutputStream.initialBufferSize",
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DEFAULT_INITIAL_BUFFER_SIZE).intValue ();
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if (r <= 0)
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r = DEFAULT_INITIAL_BUFFER_SIZE;
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initial_buffer_size = r;
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}
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}
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