+++ /dev/null
-/* InputStream.java -- Base class for input
- Copyright (C) 1998, 1999, 2001 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., 59 Temple Place, Suite 330, Boston, MA
-02111-1307 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 abstract class forms the base of the hierarchy of classes that read
- * input as a stream of bytes. It provides a common set of methods for
- * reading bytes from streams. Subclasses implement and extend these
- * methods to read bytes from a particular input source such as a file
- * or network connection.
- *
- * @author Aaron M. Renn (arenn@urbanophile.com)
- * @author Warren Levy <warrenl@cygnus.com>
- */
-public abstract class InputStream
-{
- /**
- * Default, no-arg, public constructor
- */
- public InputStream()
- {
- }
-
- /**
- * This method returns the number of bytes that can be read from this
- * stream before a read can block. A return of 0 indicates that blocking
- * might (or might not) occur on the very next read attempt.
- * <p>
- * This method always returns 0 in this class
- *
- * @return The number of bytes that can be read before blocking could occur
- *
- * @exception IOException If an error occurs
- */
- public int available() throws IOException
- {
- return 0;
- }
-
- /**
- * This method closes the stream. Any futher attempts to read from the
- * stream may generate an <code>IOException</code>
- * <p>
- * This method does nothing in this class, but subclasses may override
- * this method in order to provide additional functionality.
- *
- * @exception IOException If an error occurs, which can only happen
- * in a subclass
- */
- public void close() throws IOException
- {
- // Do nothing
- }
-
- /**
- * This method marks a position in the input to which the stream can
- * be "reset" by calling the <code>reset()</code> method. The
- * parameter @code{readlimit} is the number of bytes that can be read
- * from the stream after setting the mark before the mark becomes
- * invalid. For example, if <code>mark()</code> is called with a
- * read limit of 10, then when 11 bytes of data are read from the
- * stream before the <code>reset()</code> method is called, then the
- * mark is invalid and the stream object instance is not required to
- * remember the mark.
- * <p>
- * This method does nothing in this class, but subclasses may override it
- * to provide mark/reset functionality.
- *
- * @param readLimit The number of bytes that can be read before the
- * mark becomes invalid
- */
- public void mark(int readlimit)
- {
- // Do nothing
- }
-
- /**
- * This method returns a boolean that indicates whether the mark/reset
- * methods are supported in this class. Those methods can be used to
- * remember a specific point in the stream and reset the stream to that
- * point.
- * <p>
- * This method always returns <code>false</code> in this class, but
- * subclasses can override this method to return </code>true</code>
- * if they support mark/reset functionality.
- *
- * @return <code>true</code> if mark/reset functionality is
- * supported, <code>false</code> otherwise
- */
- public boolean markSupported()
- {
- return false;
- }
-
- /**
- * This method reads an unsigned byte from the input stream and returns it
- * as an int in the range of 0-255. This method also will return -1 if
- * the end of the stream has been reached.
- * <p>
- * This method will block until the byte can be read.
- *
- * @return The byte read or -1 if end of stream
- *
- * @exception IOException If an error occurs
- */
- public abstract int read() throws IOException;
-
- /**
- * This method reads bytes from a stream and stores them into a caller
- * supplied buffer. This method attempts to completely fill the buffer,
- * but can return before doing so. The actual number of bytes 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 operates by calling an overloaded read method like so:
- * <code>read(b, 0, b.length)</code>
- *
- * @param b The buffer into which the bytes read will be stored.
- *
- * @return The number of bytes read or -1 if end of stream.
- *
- * @exception IOException If an error occurs.
- */
- public int read(byte[] b) throws IOException
- {
- return read(b, 0, b.length);
- }
-
- /**
- * This method read bytes from a stream and stores them into a
- * caller supplied buffer. It starts storing the data at index
- * <code>off</code> into the buffer and attempts to read
- * <code>len</code> bytes. This method can return before reading the
- * number of bytes requested. The actual number of bytes 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 operates by calling the single byte <code>read()</code> method
- * in a loop until the desired number of bytes are read. The read loop
- * stops short if the end of the stream is encountered or if an IOException
- * is encountered on any read operation except the first. If the first
- * attempt to read a bytes fails, the IOException is allowed to propagate
- * upward. And subsequent IOException is caught and treated identically
- * to an end of stream condition. Subclasses can (and should if possible)
- * override this method to provide a more efficient implementation.
- *
- * @param b The array into which the bytes read should be stored
- * @param off The offset into the array to start storing bytes
- * @param len The requested number of bytes to read
- *
- * @return The actual number of bytes read, or -1 if end of stream.
- *
- * @exception IOException If an error occurs.
- */
- public int read(byte[] b, int off, int len) throws IOException
- {
- if (off < 0 || len < 0 || off + len > b.length)
- throw new IndexOutOfBoundsException();
- if (b.length == 0)
- return 0;
-
- int i, ch;
-
- for (i = 0; i < len; ++i)
- try
- {
- if ((ch = read()) < 0)
- return i == 0 ? -1 : i; // EOF
- b[off + i] = (byte) ch;
- }
- catch (IOException ex)
- {
- // Only reading the first byte should cause an IOException.
- if (i == 0)
- throw ex;
- return i;
- }
-
- return i;
- }
-
- /**
- * This method resets a stream to the point where the
- * <code>mark()</code> method was called. Any bytes that were read
- * after the mark point was set will be re-read during subsequent
- * reads.
- * <p>
- * This method always throws an IOException in this class, but subclasses
- * can override this method if they provide mark/reset functionality.
- *
- * @exception IOException Always thrown for this class
- */
- public void reset() throws IOException
- {
- throw new IOException("mark/reset not supported");
- }
-
- /**
- * This method skips the specified number of bytes in the stream. It
- * returns the actual number of bytes skipped, which may be less than the
- * requested amount.
- * <p>
- * This method reads and discards bytes into a byte array until the
- * specified number of bytes were skipped or until either the end of stream
- * is reached or a read attempt returns a short count. Subclasses can
- * override this metho to provide a more efficient implementation where
- * one exists.
- *
- * @param n The requested number of bytes to skip
- *
- * @return The actual number of bytes skipped.
- *
- * @exception IOException If an error occurs
- */
- public long skip(long n) throws IOException
- {
- // Throw away n bytes by reading them into a temp byte[].
- // Limit the temp array to 2Kb so we don't grab too much memory.
- final int buflen = n > 2048 ? 2048 : (int) n;
- byte[] tmpbuf = new byte[buflen];
- final long origN = n;
-
- while (n > 0L)
- {
- int numread = read(tmpbuf, 0, n > buflen ? buflen : (int) n);
- if (numread <= 0)
- break;
- n -= numread;
- }
-
- return origN - n;
- }
-}
projects / msp430-gcc.git / blobdiff