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* java/io/BufferedInputStream.java: Merge with Classpath
From-SVN: r46086
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@ -1,3 +1,7 @@
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2001-10-06 Mark Wielaard <mark@klomp.org>
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* java/io/BufferedInputStream.java: Merge with Classpath
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2001-10-07 Joseph S. Myers <jsm28@cam.ac.uk>
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* defineclass.cc, java/awt/image/ColorModel.java,
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@ -1,45 +1,118 @@
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/* Copyright (C) 1998, 1999, 2001 Free Software Foundation
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/* BufferedInputStream.java -- An input stream that implements buffering
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Copyright (C) 1998, 1999, 2001 Free Software Foundation, Inc.
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This file is part of libgcj.
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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., 59 Temple Place, Suite 330, Boston, MA
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02111-1307 USA.
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As a special exception, if you link this library with other files to
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produce an executable, this library does not by itself cause the
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resulting executable to be covered by the GNU General Public License.
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This exception does not however invalidate any other reasons why the
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executable file might be covered by the GNU General Public License. */
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This software is copyrighted work licensed under the terms of the
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Libgcj License. Please consult the file "LIBGCJ_LICENSE" for
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details. */
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package java.io;
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/**
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* @author Warren Levy <warrenl@cygnus.com>
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* @date October 8, 1998.
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*/
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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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* plus online API docs for JDK 1.2 beta from http://www.javasoft.com.
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* Status: Believed complete and correct.
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*/
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/**
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* This subclass of <code>FilterInputStream</code> buffers input from an
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* underlying implementation to provide a possibly more efficient read
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* mechanism. It maintains the buffer and buffer state in instance
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* variables that are available to subclasses. The default buffer size
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* of 2048 bytes can be overridden by the creator of the stream.
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* <p>
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* This class also implements mark/reset functionality. It is capable
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* of remembering any number of input bytes, to the limits of
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* system memory or the size of <code>Integer.MAX_VALUE</code>
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* <p>
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* Please note that this class does not properly handle character
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* encodings. Consider using the <code>BufferedReader</code> class which
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* does.
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*
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* @author Aaron M. Renn (arenn@urbanophile.com)
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* @author Warren Levy <warrenl@cygnus.com>
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*/
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public class BufferedInputStream extends FilterInputStream
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{
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/* Internal buffer array for data. */
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/**
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* This is the default buffer size
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*/
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private static final int DEFAULT_BUFFER_SIZE = 2048;
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/**
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* The buffer used for storing data from the underlying stream.
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*/
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protected byte[] buf;
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/* Index one greater than the last valid byte in the buffer. */
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/**
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* The number of valid bytes currently in the buffer. It is also the index
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* of the buffer position one byte past the end of the valid data.
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*/
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protected int count = 0;
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/* The current position in the buffer. */
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/**
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* The index of the next character that will by read from the buffer.
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* When <code>pos == count</code>, the buffer is empty.
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*/
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protected int pos = 0;
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/* The value of pos the last time mark() was called. */
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/**
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* The value of <code>pos</code> when the <code>mark()</code> method was
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* called.
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* This is set to -1 if there is no mark set.
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*/
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protected int markpos = -1;
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/* The maximum read-ahead allowed before calls to reset() fail. */
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/**
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* This is the maximum number of bytes than can be read after a
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* call to <code>mark()</code> before the mark can be discarded.
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* After this may bytes are read, the <code>reset()</code> method
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* may not be called successfully.
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*/
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protected int marklimit = 0;
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/**
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* This method initializes a new <code>BufferedInputStream</code> that will
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* read from the specified subordinate stream with a default buffer size
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* of 2048 bytes
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*
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* @param in The subordinate stream to read from
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*/
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public BufferedInputStream(InputStream in)
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{
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this(in, 2048);
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this(in, DEFAULT_BUFFER_SIZE);
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}
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/**
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* This method initializes a new <code>BufferedInputStream</code> that will
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* read from the specified subordinate stream with a buffer size that
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* is specified by the caller.
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*
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* @param in The subordinate stream to read from
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* @param size The buffer size to use
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*
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* @exception IllegalArgumentException when size is smaller then 1
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*/
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public BufferedInputStream(InputStream in, int size)
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{
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super(in);
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@ -48,11 +121,30 @@ public class BufferedInputStream extends FilterInputStream
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buf = new byte[size];
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}
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/**
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* This method returns the number of bytes that can be read from this
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* stream before a read can block. A return of 0 indicates that blocking
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* might (or might not) occur on the very next read attempt.
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* <p>
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* The number of available bytes will be the number of read ahead bytes
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* stored in the internal buffer plus the number of available bytes in
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* the underlying stream.
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*
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* @return The number of bytes that can be read before blocking could occur
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*
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* @exception IOException If an error occurs
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*/
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public synchronized int available() throws IOException
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{
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return count - pos + super.available();
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}
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/**
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* This method closes the underlying input stream and frees any
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* resources associated with it. Sets <code>buf</code> to <code>null</code>.
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*
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* @exception IOException If an error occurs.
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*/
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public void close() throws IOException
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{
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// Free up the array memory.
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@ -60,17 +152,54 @@ public class BufferedInputStream extends FilterInputStream
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super.close();
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}
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/**
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* This method marks a position in the input to which the stream can be
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* "reset" by calling the <code>reset()</code> method. The parameter
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* <code>readlimit</code> is the number of bytes that can be read from the
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* stream after setting the mark before the mark becomes invalid. For
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* example, if <code>mark()</code> is called with a read limit of 10, then
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* when 11 bytes of data are read from the stream before the
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* <code>reset()</code> method is called, then the mark is invalid and the
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* stream object instance is not required to remember the mark.
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* <p>
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* Note that the number of bytes that can be remembered by this method
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* can be greater than the size of the internal read buffer. It is also
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* not dependent on the subordinate stream supporting mark/reset
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* functionality.
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*
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* @param readlimit The number of bytes that can be read before the mark
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* becomes invalid
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*/
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public synchronized void mark(int readlimit)
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{
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marklimit = readlimit;
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markpos = pos;
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}
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/**
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* This method returns <code>true</code> to indicate that this class
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* supports mark/reset functionality.
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*
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* @return <code>true</code> to indicate that mark/reset functionality is
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* supported
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*
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*/
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public boolean markSupported()
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{
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return true;
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}
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/**
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* This method reads an unsigned byte from the input stream and returns it
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* as an int in the range of 0-255. This method also will return -1 if
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* the end of the stream has been reached.
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* <p>
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* This method will block until the byte can be read.
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*
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* @return The byte read or -1 if end of stream
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*
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* @exception IOException If an error occurs
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*/
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public synchronized int read() throws IOException
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{
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if (pos >= count && !refill())
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@ -82,10 +211,31 @@ public class BufferedInputStream extends FilterInputStream
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return ((int) buf[pos++]) & 0xFF;
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}
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/**
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* This method reads bytes from a stream and stores them into a caller
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* supplied buffer. It starts storing the data at index <code>off</code>
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* into the buffer and attempts to read <code>len</code> bytes. This method
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* can return before reading the number of bytes requested. The actual
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* number of bytes read is returned as an int. A -1 is returned to indicate
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* the end of the stream.
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* <p>
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* This method will block until some data can be read.
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*
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* @param b The array into which the bytes read should be stored
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* @param off The offset into the array to start storing bytes
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* @param len The requested number of bytes to read
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*
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* @return The actual number of bytes read, or -1 if end of stream.
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*
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* @exception IOException If an error occurs.
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* @exception IndexOutOfBoundsException when <code>off</code> or
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* <code>len</code> are negative, or when <code>off + len</code>
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* is larger then the size of <code>b</code>,
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*/
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public synchronized int read(byte[] b, int off, int len) throws IOException
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{
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if (off < 0 || len < 0 || off + len > b.length)
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throw new ArrayIndexOutOfBoundsException();
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throw new IndexOutOfBoundsException();
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if (pos >= count && !refill())
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return -1; // No bytes were read before EOF.
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return remain;
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}
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/**
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* This method resets a stream to the point where the <code>mark()</code>
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* method was called. Any bytes that were read after the mark point was
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* set will be re-read during subsequent reads.
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* <p>
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* This method will throw an IOException if the number of bytes read from
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* the stream since the call to <code>mark()</code> exceeds the mark limit
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* passed when establishing the mark.
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*
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* @exception IOException If <code>mark()</code> was never called or more
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* then <code>markLimit</code> bytes were read since the last
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* call to <code>mark()</code>
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*/
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public synchronized void reset() throws IOException
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{
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if (markpos < 0)
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pos = markpos;
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}
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/**
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* This method skips the specified number of bytes in the stream. It
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* returns the actual number of bytes skipped, which may be less than the
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* requested amount.
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*
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* @param n The requested number of bytes to skip
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*
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* @return The actual number of bytes skipped.
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*
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* @exception IOException If an error occurs
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*/
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public synchronized long skip(long n) throws IOException
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{
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final long origN = n;
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@ -131,6 +305,13 @@ public class BufferedInputStream extends FilterInputStream
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return origN - n;
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}
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/**
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* Called to refill the buffer (when count is equal or greater the pos).
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* Package local so BufferedReader can call it when needed.
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*
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* @return <code>true</code> when <code>buf</code> can be (partly) refilled,
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* <code>false</code> otherwise.
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*/
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boolean refill() throws IOException
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{
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if (markpos < 0)
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