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diff --git a/src/share/classes/java/io/PushbackInputStream.java b/src/share/classes/java/io/PushbackInputStream.java
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+/*
+ * Copyright 1994-2006 Sun Microsystems, Inc.  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.  Sun designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
+ * CA 95054 USA or visit www.sun.com if you need additional information or
+ * have any questions.
+ */
+
+package java.io;
+
+/**
+ * A <code>PushbackInputStream</code> adds
+ * functionality to another input stream, namely
+ * the  ability to "push back" or "unread"
+ * one byte. This is useful in situations where
+ * it is  convenient for a fragment of code
+ * to read an indefinite number of data bytes
+ * that  are delimited by a particular byte
+ * value; after reading the terminating byte,
+ * the  code fragment can "unread" it, so that
+ * the next read operation on the input stream
+ * will reread the byte that was pushed back.
+ * For example, bytes representing the  characters
+ * constituting an identifier might be terminated
+ * by a byte representing an  operator character;
+ * a method whose job is to read just an identifier
+ * can read until it  sees the operator and
+ * then push the operator back to be re-read.
+ *
+ * @author  David Connelly
+ * @author  Jonathan Payne
+ * @since   JDK1.0
+ */
+public
+class PushbackInputStream extends FilterInputStream {
+    /**
+     * The pushback buffer.
+     * @since   JDK1.1
+     */
+    protected byte[] buf;
+
+    /**
+     * The position within the pushback buffer from which the next byte will
+     * be read.  When the buffer is empty, <code>pos</code> is equal to
+     * <code>buf.length</code>; when the buffer is full, <code>pos</code> is
+     * equal to zero.
+     *
+     * @since   JDK1.1
+     */
+    protected int pos;
+
+    /**
+     * Check to make sure that this stream has not been closed
+     */
+    private void ensureOpen() throws IOException {
+        if (in == null)
+            throw new IOException("Stream closed");
+    }
+
+    /**
+     * Creates a <code>PushbackInputStream</code>
+     * with a pushback buffer of the specified <code>size</code>,
+     * and saves its  argument, the input stream
+     * <code>in</code>, for later use. Initially,
+     * there is no pushed-back byte  (the field
+     * <code>pushBack</code> is initialized to
+     * <code>-1</code>).
+     *
+     * @param  in    the input stream from which bytes will be read.
+     * @param  size  the size of the pushback buffer.
+     * @exception IllegalArgumentException if size is <= 0
+     * @since  JDK1.1
+     */
+    public PushbackInputStream(InputStream in, int size) {
+        super(in);
+        if (size <= 0) {
+            throw new IllegalArgumentException("size <= 0");
+        }
+        this.buf = new byte[size];
+        this.pos = size;
+    }
+
+    /**
+     * Creates a <code>PushbackInputStream</code>
+     * and saves its  argument, the input stream
+     * <code>in</code>, for later use. Initially,
+     * there is no pushed-back byte  (the field
+     * <code>pushBack</code> is initialized to
+     * <code>-1</code>).
+     *
+     * @param   in   the input stream from which bytes will be read.
+     */
+    public PushbackInputStream(InputStream in) {
+        this(in, 1);
+    }
+
+    /**
+     * Reads the next byte of data from this input stream. The value
+     * byte is returned as an <code>int</code> in the range
+     * <code>0</code> to <code>255</code>. If no byte is available
+     * because the end of the stream has been reached, the value
+     * <code>-1</code> is returned. This method blocks until input data
+     * is available, the end of the stream is detected, or an exception
+     * is thrown.
+     *
+     * <p> This method returns the most recently pushed-back byte, if there is
+     * one, and otherwise calls the <code>read</code> method of its underlying
+     * input stream and returns whatever value that method returns.
+     *
+     * @return     the next byte of data, or <code>-1</code> if the end of the
+     *             stream has been reached.
+     * @exception  IOException  if this input stream has been closed by
+     *             invoking its {@link #close()} method,
+     *             or an I/O error occurs.
+     * @see        java.io.InputStream#read()
+     */
+    public int read() throws IOException {
+        ensureOpen();
+        if (pos < buf.length) {
+            return buf[pos++] & 0xff;
+        }
+        return super.read();
+    }
+
+    /**
+     * Reads up to <code>len</code> bytes of data from this input stream into
+     * an array of bytes.  This method first reads any pushed-back bytes; after
+     * that, if fewer than <code>len</code> bytes have been read then it
+     * reads from the underlying input stream. If <code>len</code> is not zero, the method
+     * blocks until at least 1 byte of input is available; otherwise, no
+     * bytes are read and <code>0</code> is returned.
+     *
+     * @param      b     the buffer into which the data is read.
+     * @param      off   the start offset in the destination array <code>b</code>
+     * @param      len   the maximum number of bytes read.
+     * @return     the total number of bytes read into the buffer, or
+     *             <code>-1</code> if there is no more data because the end of
+     *             the stream has been reached.
+     * @exception  NullPointerException If <code>b</code> is <code>null</code>.
+     * @exception  IndexOutOfBoundsException If <code>off</code> is negative,
+     * <code>len</code> is negative, or <code>len</code> is greater than
+     * <code>b.length - off</code>
+     * @exception  IOException  if this input stream has been closed by
+     *             invoking its {@link #close()} method,
+     *             or an I/O error occurs.
+     * @see        java.io.InputStream#read(byte[], int, int)
+     */
+    public int read(byte[] b, int off, int len) throws IOException {
+        ensureOpen();
+        if (b == null) {
+            throw new NullPointerException();
+        } else if (off < 0 || len < 0 || len > b.length - off) {
+            throw new IndexOutOfBoundsException();
+        } else if (len == 0) {
+            return 0;
+        }
+
+        int avail = buf.length - pos;
+        if (avail > 0) {
+            if (len < avail) {
+                avail = len;
+            }
+            System.arraycopy(buf, pos, b, off, avail);
+            pos += avail;
+            off += avail;
+            len -= avail;
+        }
+        if (len > 0) {
+            len = super.read(b, off, len);
+            if (len == -1) {
+                return avail == 0 ? -1 : avail;
+            }
+            return avail + len;
+        }
+        return avail;
+    }
+
+    /**
+     * Pushes back a byte by copying it to the front of the pushback buffer.
+     * After this method returns, the next byte to be read will have the value
+     * <code>(byte)b</code>.
+     *
+     * @param      b   the <code>int</code> value whose low-order
+     *                  byte is to be pushed back.
+     * @exception IOException If there is not enough room in the pushback
+     *            buffer for the byte, or this input stream has been closed by
+     *            invoking its {@link #close()} method.
+     */
+    public void unread(int b) throws IOException {
+        ensureOpen();
+        if (pos == 0) {
+            throw new IOException("Push back buffer is full");
+        }
+        buf[--pos] = (byte)b;
+    }
+
+    /**
+     * Pushes back a portion of an array of bytes by copying it to the front
+     * of the pushback buffer.  After this method returns, the next byte to be
+     * read will have the value <code>b[off]</code>, the byte after that will
+     * have the value <code>b[off+1]</code>, and so forth.
+     *
+     * @param b the byte array to push back.
+     * @param off the start offset of the data.
+     * @param len the number of bytes to push back.
+     * @exception IOException If there is not enough room in the pushback
+     *            buffer for the specified number of bytes,
+     *            or this input stream has been closed by
+     *            invoking its {@link #close()} method.
+     * @since     JDK1.1
+     */
+    public void unread(byte[] b, int off, int len) throws IOException {
+        ensureOpen();
+        if (len > pos) {
+            throw new IOException("Push back buffer is full");
+        }
+        pos -= len;
+        System.arraycopy(b, off, buf, pos, len);
+    }
+
+    /**
+     * Pushes back an array of bytes by copying it to the front of the
+     * pushback buffer.  After this method returns, the next byte to be read
+     * will have the value <code>b[0]</code>, the byte after that will have the
+     * value <code>b[1]</code>, and so forth.
+     *
+     * @param b the byte array to push back
+     * @exception IOException If there is not enough room in the pushback
+     *            buffer for the specified number of bytes,
+     *            or this input stream has been closed by
+     *            invoking its {@link #close()} method.
+     * @since     JDK1.1
+     */
+    public void unread(byte[] b) throws IOException {
+        unread(b, 0, b.length);
+    }
+
+    /**
+     * Returns an estimate of the number of bytes that can be read (or
+     * skipped over) from this input stream without blocking by the next
+     * invocation of a method for this input stream. The next invocation might be
+     * the same thread or another thread.  A single read or skip of this
+     * many bytes will not block, but may read or skip fewer bytes.
+     *
+     * <p> The method returns the sum of the number of bytes that have been
+     * pushed back and the value returned by {@link
+     * java.io.FilterInputStream#available available}.
+     *
+     * @return     the number of bytes that can be read (or skipped over) from
+     *             the input stream without blocking.
+     * @exception  IOException  if this input stream has been closed by
+     *             invoking its {@link #close()} method,
+     *             or an I/O error occurs.
+     * @see        java.io.FilterInputStream#in
+     * @see        java.io.InputStream#available()
+     */
+    public int available() throws IOException {
+        ensureOpen();
+        return (buf.length - pos) + super.available();
+    }
+
+    /**
+     * Skips over and discards <code>n</code> bytes of data from this
+     * input stream. The <code>skip</code> method may, for a variety of
+     * reasons, end up skipping over some smaller number of bytes,
+     * possibly zero.  If <code>n</code> is negative, no bytes are skipped.
+     *
+     * <p> The <code>skip</code> method of <code>PushbackInputStream</code>
+     * first skips over the bytes in the pushback buffer, if any.  It then
+     * calls the <code>skip</code> method of the underlying input stream if
+     * more bytes need to be skipped.  The actual number of bytes skipped
+     * is returned.
+     *
+     * @param      n  {@inheritDoc}
+     * @return     {@inheritDoc}
+     * @exception  IOException  if the stream does not support seek,
+     *            or the stream has been closed by
+     *            invoking its {@link #close()} method,
+     *            or an I/O error occurs.
+     * @see        java.io.FilterInputStream#in
+     * @see        java.io.InputStream#skip(long n)
+     * @since      1.2
+     */
+    public long skip(long n) throws IOException {
+        ensureOpen();
+        if (n <= 0) {
+            return 0;
+        }
+
+        long pskip = buf.length - pos;
+        if (pskip > 0) {
+            if (n < pskip) {
+                pskip = n;
+            }
+            pos += pskip;
+            n -= pskip;
+        }
+        if (n > 0) {
+            pskip += super.skip(n);
+        }
+        return pskip;
+    }
+
+    /**
+     * Tests if this input stream supports the <code>mark</code> and
+     * <code>reset</code> methods, which it does not.
+     *
+     * @return   <code>false</code>, since this class does not support the
+     *           <code>mark</code> and <code>reset</code> methods.
+     * @see     java.io.InputStream#mark(int)
+     * @see     java.io.InputStream#reset()
+     */
+    public boolean markSupported() {
+        return false;
+    }
+
+    /**
+     * Marks the current position in this input stream.
+     *
+     * <p> The <code>mark</code> method of <code>PushbackInputStream</code>
+     * does nothing.
+     *
+     * @param   readlimit   the maximum limit of bytes that can be read before
+     *                      the mark position becomes invalid.
+     * @see     java.io.InputStream#reset()
+     */
+    public synchronized void mark(int readlimit) {
+    }
+
+    /**
+     * Repositions this stream to the position at the time the
+     * <code>mark</code> method was last called on this input stream.
+     *
+     * <p> The method <code>reset</code> for class
+     * <code>PushbackInputStream</code> does nothing except throw an
+     * <code>IOException</code>.
+     *
+     * @exception  IOException  if this method is invoked.
+     * @see     java.io.InputStream#mark(int)
+     * @see     java.io.IOException
+     */
+    public synchronized void reset() throws IOException {
+        throw new IOException("mark/reset not supported");
+    }
+
+    /**
+     * Closes this input stream and releases any system resources
+     * associated with the stream.
+     * Once the stream has been closed, further read(), unread(),
+     * available(), reset(), or skip() invocations will throw an IOException.
+     * Closing a previously closed stream has no effect.
+     *
+     * @exception  IOException  if an I/O error occurs.
+     */
+    public synchronized void close() throws IOException {
+        if (in == null)
+            return;
+        in.close();
+        in = null;
+        buf = null;
+    }
+}