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diff --git a/libjava/classpath/java/io/PushbackReader.java b/libjava/classpath/java/io/PushbackReader.java
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+/* PushbackReader.java -- An character stream that can unread chars
+   Copyright (C) 1998, 2000, 2001, 2003, 2005  Free Software Foundation, Inc.
+
+This file is part of GNU Classpath.
+
+GNU Classpath is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 2, or (at your option)
+any later version.
+
+GNU Classpath 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 for more details.
+
+You should have received a copy of the GNU General Public License
+along with GNU Classpath; see the file COPYING.  If not, write to the
+Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+02110-1301 USA.
+
+Linking this library statically or dynamically with other modules is
+making a combined work based on this library.  Thus, the terms and
+conditions of the GNU General Public License cover the whole
+combination.
+
+As a special exception, the copyright holders of this library give you
+permission to link this library with independent modules to produce an
+executable, regardless of the license terms of these independent
+modules, and to copy and distribute the resulting executable under
+terms of your choice, provided that you also meet, for each linked
+independent module, the terms and conditions of the license of that
+module.  An independent module is a module which is not derived from
+or based on this library.  If you modify this library, you may extend
+this exception to your version of the library, but you are not
+obligated to do so.  If you do not wish to do so, delete this
+exception statement from your version. */
+
+
+package java.io;
+
+/**
+ * This subclass of <code>FilterReader</code> provides the ability to
+ * unread data from a stream.  It maintains an internal buffer of unread
+ * data that is supplied to the next read operation.  This is conceptually
+ * similar to mark/reset functionality, except that in this case the
+ * position to reset the stream to does not need to be known in advance.
+ * <p>
+ * The default pushback buffer size one char, but this can be overridden
+ * by the creator of the stream.
+ *
+ * @author Aaron M. Renn (arenn@urbanophile.com)
+ * @author Warren Levy (warrenl@cygnus.com)
+ */
+public class PushbackReader extends FilterReader
+{
+  /**
+   * This is the default buffer size
+   */
+  private static final int DEFAULT_BUFFER_SIZE = 1;
+
+  /**
+   * This is the buffer that is used to store the pushed back data
+   */
+  private char[] buf;
+
+  /**
+   * This is the position in the buffer from which the next char will be
+   * read.  Bytes are stored in reverse order in the buffer, starting from
+   * <code>buf[buf.length - 1]</code> to <code>buf[0]</code>.  Thus when
+   * <code>pos</code> is 0 the buffer is full and <code>buf.length</code> when
+   * it is empty
+   */
+  private int pos;
+
+  /**
+   * This method initializes a <code>PushbackReader</code> to read from the
+   * specified subordinate <code>Reader</code> with a default pushback buffer
+   * size of 1.
+   *
+   * @param in The subordinate stream to read from
+   */
+  public PushbackReader(Reader in)
+  {
+    this(in, DEFAULT_BUFFER_SIZE);
+  }
+
+  /**
+   * This method initializes a <code>PushbackReader</code> to read from the
+   * specified subordinate <code>Reader</code> with the specified buffer
+   * size
+   *
+   * @param in The subordinate <code>Reader</code> to read from
+   * @param bufsize The pushback buffer size to use
+   */
+  public PushbackReader(Reader in, int bufsize)
+  {
+    super(in);
+
+    if (bufsize < 0)
+      throw new IllegalArgumentException("buffer size must be positive");
+
+    buf = new char[bufsize];
+    pos = bufsize;
+  }
+
+  /**
+   * This method closes the stream and frees any associated resources.
+   *
+   * @exception IOException If an error occurs.
+   */
+  public void close() throws IOException
+  {
+    synchronized (lock)
+      {
+        buf = null;
+        super.close();
+      }
+  }
+
+  /**
+   * This method throws an exception when called since this class does
+   * not support mark/reset.
+   *
+   * @param read_limit Not used.
+   *
+   * @exception IOException Always thrown to indicate mark/reset not supported.
+   */
+  public void mark(int read_limit) throws IOException
+  {
+    throw new IOException("mark not supported in this class");
+  }
+
+  /**
+   * This method returns <code>false</code> to indicate that it does not support
+   * mark/reset functionality.
+   *
+   * @return This method returns <code>false</code> to indicate that this
+   * class does not support mark/reset functionality
+   *
+   */
+  public boolean markSupported()
+  {
+    return(false);
+  }
+
+  /**
+   * This method always throws an IOException in this class because
+   * mark/reset functionality is not supported.
+   *
+   * @exception IOException Always thrown for this class
+   */
+  public void reset() throws IOException
+  {
+    throw new IOException("reset not supported in this class");
+  }
+
+  /**
+   * This method determines whether or not this stream is ready to be read.
+   * If it returns <code>false</code> to indicate that the stream is not
+   * ready, any attempt to read from the stream could (but is not
+   * guaranteed to) block.
+   * <p>
+   * This stream is ready to read if there are either chars waiting to be
+   * read in the pushback buffer or if the underlying stream is ready to
+   * be read.
+   *
+   * @return <code>true</code> if this stream is ready to be read,
+   * <code>false</code> otherwise
+   *
+   * @exception IOException If an error occurs
+   */
+  public boolean ready() throws IOException
+  {
+    synchronized (lock)
+      {
+        if (buf == null)
+          throw new IOException ("stream closed");
+
+        if (((buf.length - pos) > 0) || super.ready())
+          return(true);
+        else
+          return(false);
+      }
+  }
+
+  // Don't delete this method just because the spec says it shouldn't be there!
+  // See the CVS log for details.
+  /**
+    * This method skips the specified number of chars in the stream.  It
+    * returns the actual number of chars skipped, which may be less than the
+    * requested amount.
+    * <p>
+    * This method first discards chars from the buffer, then calls the
+    * <code>skip</code> method on the underlying <code>Reader</code> to
+    * skip additional chars if necessary.
+    *
+    * @param num_chars The requested number of chars to skip
+    *
+    * @return The actual number of chars skipped.
+    *
+    * @exception IOException If an error occurs
+    */
+  public long skip(long num_chars) throws IOException
+  {
+    synchronized (lock)
+      {
+        if (num_chars <= 0)
+          return(0);
+
+        if ((buf.length - pos) >= num_chars)
+          {
+            pos += num_chars;
+            return(num_chars);
+          }
+
+        int chars_discarded = buf.length - pos;
+        pos = buf.length;
+
+        long chars_skipped = in.skip(num_chars - chars_discarded);
+
+        return(chars_discarded + chars_skipped);
+      }
+  }
+
+  /**
+   * This method reads an unsigned char from the input stream and returns it
+   * as an int in the range of 0-65535.  This method also will return -1 if
+   * the end of the stream has been reached.  The char returned will be read
+   * from the pushback buffer, unless the buffer is empty, in which case
+   * the char will be read from the underlying stream.
+   * <p>
+   * This method will block until the char can be read.
+   *
+   * @return The char read or -1 if end of stream
+   *
+   * @exception IOException If an error occurs
+   */
+  public int read() throws IOException
+  {
+    synchronized (lock)
+      {
+        if (buf == null)
+          throw new IOException("stream closed");
+
+        if (pos == buf.length)
+          return(super.read());
+
+        ++pos;
+        return((buf[pos - 1] & 0xFFFF));
+      }
+  }
+
+  /**
+   * This method read chars from a stream and stores them into a caller
+   * supplied buffer.  It starts storing the data at index <code>offset</code>
+   * into
+   * the buffer and attempts to read <code>len</code> chars.  This method can
+   * return before reading the number of chars requested.  The actual number
+   * of chars read is returned as an int.  A -1 is returned to indicate the
+   * end of the stream.
+   *  <p>
+   * This method will block until some data can be read.
+   * <p>
+   * This method first reads chars from the pushback buffer in order to
+   * satisfy the read request.  If the pushback buffer cannot provide all
+   * of the chars requested, the remaining chars are read from the
+   * underlying stream.
+   *
+   * @param buffer The array into which the chars read should be stored
+   * @param offset The offset into the array to start storing chars
+   * @param length The requested number of chars to read
+   *
+   * @return The actual number of chars read, or -1 if end of stream.
+   *
+   * @exception IOException If an error occurs.
+   */
+  public synchronized int read(char[] buffer, int offset, int length)
+    throws IOException
+  {
+    synchronized (lock)
+      {
+        if (buf == null)
+          throw new IOException("stream closed");
+
+        if (offset < 0 || length < 0 || offset + length > buffer.length)
+          throw new ArrayIndexOutOfBoundsException();
+
+        int numBytes = Math.min(buf.length - pos, length);
+        if (numBytes > 0)
+          {
+            System.arraycopy (buf, pos, buffer, offset, numBytes);
+            pos += numBytes;
+            return numBytes;
+          }
+
+        return super.read(buffer, offset, length);
+      }
+  }
+
+  /**
+   * This method pushes a single char of data into the pushback buffer.
+   * The char pushed back is the one that will be returned as the first char
+   * of the next read.
+   * <p>
+   * If the pushback buffer is full, this method throws an exception.
+   * <p>
+   * The argument to this method is an <code>int</code>.  Only the low eight
+   * bits of this value are pushed back.
+   *
+   * @param b The char to be pushed back, passed as an int
+   *
+   * @exception IOException If the pushback buffer is full.
+   */
+  public void unread(int b) throws IOException
+  {
+    synchronized (lock)
+      {
+        if (buf == null)
+          throw new IOException("stream closed");
+        if (pos == 0)
+          throw new IOException("Pushback buffer is full");
+
+        --pos;
+        buf[pos] = (char)(b & 0xFFFF);
+      }
+  }
+
+  /**
+   * This method pushes all of the chars in the passed char array into
+   * the pushback buffer.  These chars are pushed in reverse order so that
+   * the next char read from the stream after this operation will be
+   * <code>buf[0]</code> followed by <code>buf[1]</code>, etc.
+   * <p>
+   * If the pushback buffer cannot hold all of the requested chars, an
+   * exception is thrown.
+   *
+   * @param buf The char array to be pushed back
+   *
+   * @exception IOException If the pushback buffer is full
+   */
+  public synchronized void unread(char[] buf) throws IOException
+  {
+    unread(buf, 0, buf.length);
+  }
+
+  /**
+   * This method pushed back chars from the passed in array into the pushback
+   * buffer.  The chars from <code>buf[offset]</code> to
+   * <code>buf[offset + len]</code>
+   * are pushed in reverse order so that the next char read from the stream
+   * after this operation will be <code>buf[offset]</code> followed by
+   * <code>buf[offset + 1]</code>, etc.
+   * <p>
+   * If the pushback buffer cannot hold all of the requested chars, an
+   * exception is thrown.
+   *
+   * @param buffer The char array to be pushed back
+   * @param offset The index into the array where the chars to be push start
+   * @param length The number of chars to be pushed.
+   *
+   * @exception IOException If the pushback buffer is full
+   */
+  public synchronized void unread(char[] buffer, int offset, int length)
+    throws IOException
+  {
+    synchronized (lock)
+      {
+        if (buf == null)
+          throw new IOException("stream closed");
+        if (pos < length)
+          throw new IOException("Pushback buffer is full");
+
+        // Note the order that these chars are being added is the opposite
+        // of what would be done if they were added to the buffer one at a time.
+        // See the Java Class Libraries book p. 1397.
+        System.arraycopy(buffer, offset, buf, pos - length, length);
+
+        // Don't put this into the arraycopy above, an exception might be thrown
+        // and in that case we don't want to modify pos.
+        pos -= length;
+      }
+  }
+}