content: /*
   * Copyright (c) 1994, 2013, Oracle and/or its affiliates. All rights reserved.
   * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   *
   * This code is free software; you can redistribute it and/or modify it
   * under the terms of the GNU General Public License version 2 only, as
   * published by the Free Software Foundation.  Oracle designates this
   * particular file as subject to the "Classpath" exception as provided
   * by Oracle in the LICENSE file that accompanied this code.
   *
   * This code is distributed in the hope that it will be useful, but WITHOUT
   * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
   * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
   * version 2 for more details (a copy is included in the LICENSE file that
   * accompanied this code).
   *
   * You should have received a copy of the GNU General Public License version
   * 2 along with this work; if not, write to the Free Software Foundation,
   * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
   *
   * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
   * or visit www.oracle.com if you need additional information or have any
   * questions.
   */
  
  package java.io;
  
  import java.util.Arrays;
  
  /**
   * This class implements an output stream in which the data is
   * written into a byte array. The buffer automatically grows as data
   * is written to it.
   * The data can be retrieved using <code>toByteArray()</code> and
   * <code>toString()</code>.
   * <p>
   * Closing a <tt>ByteArrayOutputStream</tt> has no effect. The methods in
   * this class can be called after the stream has been closed without
   * generating an <tt>IOException</tt>.
   *
   * @author  Arthur van Hoff
   * @since   JDK1.0
   */
  
  public class ByteArrayOutputStream extends OutputStream {
  
      /**
       * The buffer where data is stored.
       */
      protected byte buf[];
  
      /**
       * The number of valid bytes in the buffer.
       */
      protected int count;
  
      /**
       * Creates a new byte array output stream. The buffer capacity is
       * initially 32 bytes, though its size increases if necessary.
       */
      public ByteArrayOutputStream() {
          this(32);
      }
  
      /**
       * Creates a new byte array output stream, with a buffer capacity of
       * the specified size, in bytes.
       *
       * @param   size   the initial size.
       * @exception  IllegalArgumentException if size is negative.
       */
      public ByteArrayOutputStream(int size) {
          if (size < 0) {
              throw new IllegalArgumentException("Negative initial size: "
                                                 + size);
          }
          buf = new byte[size];
      }
  
      /**
       * Increases the capacity if necessary to ensure that it can hold
       * at least the number of elements specified by the minimum
       * capacity argument.
       *
       * @param minCapacity the desired minimum capacity
       * @throws OutOfMemoryError if {@code minCapacity < 0}.  This is
       * interpreted as a request for the unsatisfiably large capacity
       * {@code (long) Integer.MAX_VALUE + (minCapacity - Integer.MAX_VALUE)}.
       */
      private void ensureCapacity(int minCapacity) {
          // overflow-conscious code
          if (minCapacity - buf.length > 0)
              grow(minCapacity);
      }
  
      /**
       * The maximum size of array to allocate.
       * Some VMs reserve some header words in an array.
       * Attempts to allocate larger arrays may result in
       * OutOfMemoryError: Requested array size exceeds VM limit
       */
      private static final int MAX_ARRAY_SIZE = Integer.MAX_VALUE - 8;
  
      /**
       * Increases the capacity to ensure that it can hold at least the
       * number of elements specified by the minimum capacity argument.
       *
       * @param minCapacity the desired minimum capacity
       */
      private void grow(int minCapacity) {
          // overflow-conscious code
          int oldCapacity = buf.length;
          int newCapacity = oldCapacity << 1;
          if (newCapacity - minCapacity < 0)
              newCapacity = minCapacity;
          if (newCapacity - MAX_ARRAY_SIZE > 0)
              newCapacity = hugeCapacity(minCapacity);
          buf = Arrays.copyOf(buf, newCapacity);
      }
  
      private static int hugeCapacity(int minCapacity) {
          if (minCapacity < 0) // overflow
              throw new OutOfMemoryError();
          return (minCapacity > MAX_ARRAY_SIZE) ?
              Integer.MAX_VALUE :
              MAX_ARRAY_SIZE;
      }
  
      /**
       * Writes the specified byte to this byte array output stream.
       *
       * @param   b   the byte to be written.
       */
      public synchronized void write(int b) {
          ensureCapacity(count + 1);
          buf[count] = (byte) b;
          count += 1;
      }
  
      /**
       * Writes <code>len</code> bytes from the specified byte array
       * starting at offset <code>off</code> to this byte array output stream.
       *
       * @param   b     the data.
       * @param   off   the start offset in the data.
       * @param   len   the number of bytes to write.
       */
      public synchronized void write(byte b[], int off, int len) {
          if ((off < 0) || (off > b.length) || (len < 0) ||
              ((off + len) - b.length > 0)) {
              throw new IndexOutOfBoundsException();
          }
          ensureCapacity(count + len);
          System.arraycopy(b, off, buf, count, len);
          count += len;
      }
  
      /**
       * Writes the complete contents of this byte array output stream to
       * the specified output stream argument, as if by calling the output
       * stream's write method using <code>out.write(buf, 0, count)</code>.
       *
       * @param      out   the output stream to which to write the data.
       * @exception  IOException  if an I/O error occurs.
       */
      public synchronized void writeTo(OutputStream out) throws IOException {
          out.write(buf, 0, count);
      }
  
      /**
       * Resets the <code>count</code> field of this byte array output
       * stream to zero, so that all currently accumulated output in the
       * output stream is discarded. The output stream can be used again,
       * reusing the already allocated buffer space.
       *
       * @see     ByteArrayInputStream#count
       */
      public synchronized void reset() {
          count = 0;
      }
  
      /**
       * Creates a newly allocated byte array. Its size is the current
       * size of this output stream and the valid contents of the buffer
       * have been copied into it.
       *
       * @return  the current contents of this output stream, as a byte array.
       * @see     ByteArrayOutputStream#size()
       */
      public synchronized byte toByteArray()[] {
          return Arrays.copyOf(buf, count);
      }
  
      /**
       * Returns the current size of the buffer.
       *
       * @return  the value of the <code>count</code> field, which is the number
       *          of valid bytes in this output stream.
       * @see     ByteArrayOutputStream#count
       */
      public synchronized int size() {
          return count;
      }
  
      /**
       * Converts the buffer's contents into a string decoding bytes using the
       * platform's default character set. The length of the new <tt>String</tt>
       * is a function of the character set, and hence may not be equal to the
       * size of the buffer.
       *
       * <p> This method always replaces malformed-input and unmappable-character
       * sequences with the default replacement string for the platform's
       * default character set. The {@linkplain java.nio.charset.CharsetDecoder}
       * class should be used when more control over the decoding process is
       * required.
       *
       * @return String decoded from the buffer's contents.
       * @since  JDK1.1
       */
      public synchronized String toString() {
          return new String(buf, 0, count);
      }
  
      /**
       * Converts the buffer's contents into a string by decoding the bytes using
       * the named {@link java.nio.charset.Charset charset}. The length of the new
       * <tt>String</tt> is a function of the charset, and hence may not be equal
       * to the length of the byte array.
       *
       * <p> This method always replaces malformed-input and unmappable-character
       * sequences with this charset's default replacement string. The {@link
       * java.nio.charset.CharsetDecoder} class should be used when more control
       * over the decoding process is required.
       *
       * @param      charsetName  the name of a supported
       *             {@link java.nio.charset.Charset charset}
       * @return     String decoded from the buffer's contents.
       * @exception  UnsupportedEncodingException
       *             If the named charset is not supported
       * @since      JDK1.1
       */
      public synchronized String toString(String charsetName)
          throws UnsupportedEncodingException
      {
          return new String(buf, 0, count, charsetName);
      }
  
      /**
       * Creates a newly allocated string. Its size is the current size of
       * the output stream and the valid contents of the buffer have been
       * copied into it. Each character <i>c</i> in the resulting string is
       * constructed from the corresponding element <i>b</i> in the byte
       * array such that:
       * <blockquote><pre>
       *     c == (char)(((hibyte &amp; 0xff) &lt;&lt; 8) | (b &amp; 0xff))
       * </pre></blockquote>
       *
       * @deprecated This method does not properly convert bytes into characters.
       * As of JDK&nbsp;1.1, the preferred way to do this is via the
       * <code>toString(String enc)</code> method, which takes an encoding-name
       * argument, or the <code>toString()</code> method, which uses the
       * platform's default character encoding.
       *
       * @param      hibyte    the high byte of each resulting Unicode character.
       * @return     the current contents of the output stream, as a string.
       * @see        ByteArrayOutputStream#size()
       * @see        ByteArrayOutputStream#toString(String)
       * @see        ByteArrayOutputStream#toString()
       */
      @Deprecated
      public synchronized String toString(int hibyte) {
          return new String(buf, hibyte, 0, count);
      }
  
      /**
       * Closing a <tt>ByteArrayOutputStream</tt> has no effect. The methods in
       * this class can be called after the stream has been closed without
       * generating an <tt>IOException</tt>.
       */
      public void close() throws IOException {
      }
  
  }
  