| // ByteArrayOutputStream.java - Write bytes to an array. |
| |
| /* Copyright (C) 1998, 1999, 2000 Free Software Foundation |
| |
| This file is part of libgcj. |
| |
| This software is copyrighted work licensed under the terms of the |
| Libgcj License. Please consult the file "LIBGCJ_LICENSE" for |
| details. */ |
| |
| package java.io; |
| |
| /* Written using "Java Class Libraries", 2nd edition, ISBN 0-201-31002-3 |
| * "The Java Language Specification", ISBN 0-201-63451-1 |
| * Status: Complete to version 1.1. |
| */ |
| |
| /** |
| * This class allows data to be written to a byte array buffer and |
| * and then retrieved by an application. The internal byte array |
| * buffer is dynamically resized to hold all the data written. Please |
| * be aware that writing large amounts to data to this stream will |
| * cause large amounts of memory to be allocated. |
| * <p> |
| * The size of the internal buffer defaults to 32 and it is resized |
| * by doubling the size of the buffer. This default size can be |
| * overridden by using the |
| * <code>gnu.java.io.ByteArrayOutputStream.initialBufferSize</code> |
| * property. |
| * <p> |
| * There is a constructor that specified the initial buffer size and |
| * that is the preferred way to set that value because it it portable |
| * across all Java class library implementations. |
| * <p> |
| * Note that this class also has methods that convert the byte array |
| * buffer to a <code>String</code> using either the system default or an |
| * application specified character encoding. Thus it can handle |
| * multibyte character encodings. |
| * |
| * @version 0.0 |
| * |
| * @author Aaron M. Renn (arenn@urbanophile.com) |
| * @author Tom Tromey <tromey@cygnus.com> |
| * @date September 24, 1998 |
| */ |
| public class ByteArrayOutputStream extends OutputStream |
| { |
| /** |
| * This method initializes a new <code>ByteArrayOutputStream</code> |
| * with the default buffer size of 32 bytes. If a different initial |
| * buffer size is desired, see the constructor |
| * <code>ByteArrayOutputStream(int size)</code>. For applications |
| * where the source code is not available, the default buffer size |
| * can be set using the system property |
| * <code>gnu.java.io.ByteArrayOutputStream.initialBufferSize</code> |
| */ |
| public ByteArrayOutputStream () |
| { |
| this (initial_buffer_size); |
| } |
| |
| /** |
| * This method initializes a new <code>ByteArrayOutputStream</code> with |
| * a specified initial buffer size. |
| * |
| * @param size The initial buffer size in bytes |
| */ |
| public ByteArrayOutputStream (int size) |
| { |
| buf = new byte[size]; |
| count = 0; |
| } |
| |
| /** |
| * This method discards all of the bytes that have been written to |
| * the internal buffer so far by setting the <code>count</code> |
| * variable to 0. The internal buffer remains at its currently |
| * allocated size. |
| */ |
| public synchronized void reset () |
| { |
| count = 0; |
| } |
| |
| /** |
| * This method returns the number of bytes that have been written to |
| * the buffer so far. This is the same as the value of the protected |
| * <code>count</code> variable. If the <code>reset</code> method is |
| * called, then this value is reset as well. Note that this method does |
| * not return the length of the internal buffer, but only the number |
| * of bytes that have been written to it. |
| * |
| * @return The number of bytes in the internal buffer |
| * |
| * @see reset |
| */ |
| public int size () |
| { |
| return count; |
| } |
| |
| /** |
| * This method returns a byte array containing the bytes that have been |
| * written to this stream so far. This array is a copy of the valid |
| * bytes in the internal buffer and its length is equal to the number of |
| * valid bytes, not necessarily to the the length of the current |
| * internal buffer. Note that since this method allocates a new array, |
| * it should be used with caution when the internal buffer is very large. |
| */ |
| public synchronized byte[] toByteArray () |
| { |
| byte[] ret = new byte[count]; |
| System.arraycopy(buf, 0, ret, 0, count); |
| return ret; |
| } |
| |
| /** |
| * Returns the bytes in the internal array as a <code>String</code>. The |
| * bytes in the buffer are converted to characters using the system default |
| * encoding. There is an overloaded <code>toString()</code> method that |
| * allows an application specified character encoding to be used. |
| * |
| * @return A <code>String</code> containing the data written to this |
| * stream so far |
| */ |
| public String toString () |
| { |
| return new String (buf, 0, count); |
| } |
| |
| /** |
| * Returns the bytes in the internal array as a <code>String</code>. The |
| * bytes in the buffer are converted to characters using the specified |
| * encoding. |
| * |
| * @param enc The name of the character encoding to use |
| * |
| * @return A <code>String</code> containing the data written to this |
| * stream so far |
| * |
| * @exception UnsupportedEncodingException If the named encoding is |
| * not available |
| */ |
| public String toString (String enc) throws UnsupportedEncodingException |
| { |
| return new String (buf, 0, count, enc); |
| } |
| |
| /** |
| * This method returns the bytes in the internal array as a |
| * <code>String</code>. It uses each byte in the array as the low |
| * order eight bits of the Unicode character value and the passed in |
| * parameter as the high eight bits. |
| * <p> |
| * This method does not convert bytes to characters in the proper way and |
| * so is deprecated in favor of the other overloaded <code>toString</code> |
| * methods which use a true character encoding. |
| * |
| * @param hibyte The high eight bits to use for each character in |
| * the <code>String</code> |
| * |
| * @return A <code>String</code> containing the data written to this |
| * stream so far |
| * |
| * @deprecrated |
| */ |
| public String toString (int hibyte) |
| { |
| return new String (buf, 0, count, hibyte); |
| } |
| |
| // Resize buffer to accomodate new bytes. |
| private void resize (int add) |
| { |
| if (count + add >= buf.length) |
| { |
| int newlen = buf.length * 2; |
| if (count + add > newlen) |
| newlen = count + add; |
| byte[] newbuf = new byte[newlen]; |
| System.arraycopy(buf, 0, newbuf, 0, count); |
| buf = newbuf; |
| } |
| } |
| |
| /** |
| * This method writes the writes the specified byte into the internal |
| * buffer. |
| * |
| * @param oneByte The byte to be read passed as an int |
| */ |
| public synchronized void write (int oneByte) |
| { |
| resize (1); |
| buf[count++] = (byte) oneByte; |
| } |
| |
| /** |
| * This method writes <code>len</code> bytes from the passed in array |
| * <code>buf</code> starting at index <code>offset</code> into the |
| * internal buffer. |
| * |
| * @param buffer The byte array to write data from |
| * @param offset The index into the buffer to start writing data from |
| * @param add The number of bytes to write |
| */ |
| public synchronized void write (byte[] buffer, int offset, int add) |
| { |
| // If ADD < 0 then arraycopy will throw the appropriate error for |
| // us. |
| if (add >= 0) |
| resize (add); |
| System.arraycopy(buffer, offset, buf, count, add); |
| count += add; |
| } |
| |
| /** |
| * This method writes all the bytes that have been written to this stream |
| * from the internal buffer to the specified <code>OutputStream</code>. |
| * |
| * @param out The <code>OutputStream</code> to write to |
| * |
| * @exception IOException If an error occurs |
| */ |
| public synchronized void writeTo (OutputStream out) throws IOException |
| { |
| out.write(buf, 0, count); |
| } |
| |
| /** |
| * The internal buffer where the data written is stored |
| */ |
| protected byte[] buf; |
| |
| /** |
| * The number of bytes that have been written to the buffer |
| */ |
| protected int count; |
| |
| /** |
| * The default initial buffer size. Specified by the JCL. |
| */ |
| private static final int DEFAULT_INITIAL_BUFFER_SIZE = 32; |
| |
| // The default buffer size which can be overridden by the user. |
| private static final int initial_buffer_size; |
| |
| static |
| { |
| int r |
| = Integer.getInteger ("gnu.java.io.ByteArrayOutputStream.initialBufferSize", |
| DEFAULT_INITIAL_BUFFER_SIZE).intValue (); |
| if (r <= 0) |
| r = DEFAULT_INITIAL_BUFFER_SIZE; |
| initial_buffer_size = r; |
| } |
| } |