diff options
Diffstat (limited to 'libjava/java/io/PipedInputStream.java')
| -rw-r--r-- | libjava/java/io/PipedInputStream.java | 374 |
1 files changed, 0 insertions, 374 deletions
diff --git a/libjava/java/io/PipedInputStream.java b/libjava/java/io/PipedInputStream.java deleted file mode 100644 index beb310b4f0c..00000000000 --- a/libjava/java/io/PipedInputStream.java +++ /dev/null @@ -1,374 +0,0 @@ -/* PipedInputStream.java -- Read portion of piped streams. - Copyright (C) 1998, 1999, 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; - -// NOTE: This implementation is very similar to that of PipedReader. If you -// fix a bug in here, chances are you should make a similar change to the -// PipedReader code. - -/** - * An input stream that reads its bytes from an output stream - * to which it is connected. - * <p> - * Data is read and written to an internal buffer. It is highly recommended - * that the <code>PipedInputStream</code> and connected - * <code>PipedOutputStream</code> - * be part of different threads. If they are not, the read and write - * operations could deadlock their thread. - * - * @specnote The JDK implementation appears to have some undocumented - * functionality where it keeps track of what thread is writing - * to pipe and throws an IOException if that thread susequently - * dies. This behaviour seems dubious and unreliable - we don't - * implement it. - * - * @author Aaron M. Renn (arenn@urbanophile.com) - */ -public class PipedInputStream extends InputStream -{ - /** PipedOutputStream to which this is connected. Null only if this - * InputStream hasn't been connected yet. */ - PipedOutputStream source; - - /** Set to true if close() has been called on this InputStream. */ - boolean closed; - - - /** - * The size of the internal buffer used for input/output. - */ - /* The "Constant Field Values" Javadoc of the Sun J2SE 1.4 - * specifies 1024. - */ - protected static final int PIPE_SIZE = 1024; - - - /** - * This is the internal circular buffer used for storing bytes written - * to the pipe and from which bytes are read by this stream - */ - protected byte[] buffer = new byte[PIPE_SIZE]; - - /** - * The index into buffer where the next byte from the connected - * <code>PipedOutputStream</code> will be written. If this variable is - * equal to <code>out</code>, then the buffer is full. If set to < 0, - * the buffer is empty. - */ - protected int in = -1; - - /** - * This index into the buffer where bytes will be read from. - */ - protected int out = 0; - - /** Buffer used to implement single-argument read/receive */ - private byte[] read_buf = new byte[1]; - - /** - * Creates a new <code>PipedInputStream</code> that is not connected to a - * <code>PipedOutputStream</code>. It must be connected before bytes can - * be read from this stream. - */ - public PipedInputStream() - { - } - - /** - * This constructor creates a new <code>PipedInputStream</code> and connects - * it to the passed in <code>PipedOutputStream</code>. The stream is then - * ready for reading. - * - * @param source The <code>PipedOutputStream</code> to connect this - * stream to - * - * @exception IOException If <code>source</code> is already connected. - */ - public PipedInputStream(PipedOutputStream source) throws IOException - { - connect(source); - } - - /** - * This method connects this stream to the passed in - * <code>PipedOutputStream</code>. - * This stream is then ready for reading. If this stream is already - * connected or has been previously closed, then an exception is thrown - * - * @param src The <code>PipedOutputStream</code> to connect this stream to - * - * @exception IOException If this PipedInputStream or <code>source</code> - * has been connected already. - */ - public void connect(PipedOutputStream source) throws IOException - { - // The JDK (1.3) does not appear to check for a previously closed - // connection here. - - if (this.source != null || source.sink != null) - throw new IOException ("Already connected"); - - source.sink = this; - this.source = source; - } - - /** - * This method receives a byte of input from the source PipedOutputStream. - * If the internal circular buffer is full, this method blocks. - * - * @param val The byte to write to this stream - * - * @exception IOException if error occurs - * @specnote Weird. This method must be some sort of accident. - */ - protected synchronized void receive(int val) throws IOException - { - read_buf[0] = (byte) (val & 0xff); - receive (read_buf, 0, 1); - } - - /** - * This method is used by the connected <code>PipedOutputStream</code> to - * write bytes into the buffer. - * - * @param buf The array containing bytes to write to this stream - * @param offset The offset into the array to start writing from - * @param len The number of bytes to write. - * - * @exception IOException If an error occurs - * @specnote This code should be in PipedOutputStream.write, but we - * put it here in order to support that bizarre recieve(int) - * method. - */ - synchronized void receive(byte[] buf, int offset, int len) - throws IOException - { - if (closed) - throw new IOException ("Pipe closed"); - - int bufpos = offset; - int copylen; - - while (len > 0) - { - try - { - while (in == out) - { - // The pipe is full. Wake up any readers and wait for them. - notifyAll(); - wait(); - // The pipe could have been closed while we were waiting. - if (closed) - throw new IOException ("Pipe closed"); - } - } - catch (InterruptedException ix) - { - throw new InterruptedIOException (); - } - - if (in < 0) // The pipe is empty. - in = 0; - - // Figure out how many bytes from buf can be copied without - // overrunning out or going past the length of the buffer. - if (in < out) - copylen = Math.min (len, out - in); - else - copylen = Math.min (len, buffer.length - in); - - // Copy bytes until the pipe is filled, wrapping if necessary. - System.arraycopy(buf, bufpos, buffer, in, copylen); - len -= copylen; - bufpos += copylen; - in += copylen; - if (in == buffer.length) - in = 0; - } - // Notify readers that new data is in the pipe. - notifyAll(); - } - - /** - * This method reads one byte from the stream. - * -1 is returned to indicated that no bytes can be read - * because the end of the stream was reached. If the stream is already - * closed, a -1 will again be returned to indicate the end of the stream. - * - * <p>This method will block if no byte is available to be read.</p> - * - * @return the value of the read byte value, or -1 of the end of the stream - * was reached - * - * @throws IOException if an error occured - */ - public int read() throws IOException - { - // Method operates by calling the multibyte overloaded read method - // Note that read_buf is an internal instance variable. I allocate it - // there to avoid constant reallocation overhead for applications that - // call this method in a loop at the cost of some unneeded overhead - // if this method is never called. - - int r = read(read_buf, 0, 1); - return r != -1 ? (read_buf[0] & 0xff) : -1; - } - - /** - * This method reads bytes from the stream into a caller supplied buffer. - * It starts storing bytes at position <code>offset</code> into the - * buffer and - * reads a maximum of <code>len</code> bytes. Note that this method - * can actually - * read fewer than <code>len</code> bytes. The actual number of bytes - * read is - * returned. A -1 is returned to indicated that no bytes can be read - * because the end of the stream was reached - ie close() was called on the - * connected PipedOutputStream. - * <p> - * This method will block if no bytes are available to be read. - * - * @param buf The buffer into which bytes will be stored - * @param offset The index into the buffer at which to start writing. - * @param len The maximum number of bytes to read. - * - * @exception IOException If <code>close()</code> was called on this Piped - * InputStream. - */ - public synchronized int read(byte[] buf, int offset, int len) - throws IOException - { - if (source == null) - throw new IOException ("Not connected"); - if (closed) - throw new IOException ("Pipe closed"); - - // If the buffer is empty, wait until there is something in the pipe - // to read. - try - { - while (in < 0) - { - if (source.closed) - return -1; - wait(); - } - } - catch (InterruptedException ix) - { - throw new InterruptedIOException(); - } - - int total = 0; - int copylen; - - while (true) - { - // Figure out how many bytes from the pipe can be copied without - // overrunning in or going past the length of buf. - if (out < in) - copylen = Math.min (len, in - out); - else - copylen = Math.min (len, buffer.length - out); - - System.arraycopy (buffer, out, buf, offset, copylen); - offset += copylen; - len -= copylen; - out += copylen; - total += copylen; - - if (out == buffer.length) - out = 0; - - if (out == in) - { - // Pipe is now empty. - in = -1; - out = 0; - } - - // If output buffer is filled or the pipe is empty, we're done. - if (len == 0 || in == -1) - { - // Notify any waiting outputstream that there is now space - // to write. - notifyAll(); - return total; - } - } - } - - /** - * This method returns the number of bytes that can be read from this stream - * before blocking could occur. This is the number of bytes that are - * currently unread in the internal circular buffer. Note that once this - * many additional bytes are read, the stream may block on a subsequent - * read, but it not guaranteed to block. - * - * @return The number of bytes that can be read before blocking might occur - * - * @exception IOException If an error occurs - */ - public synchronized int available() throws IOException - { - // The JDK 1.3 implementation does not appear to check for the closed or - // unconnected stream conditions here. - - if (in < 0) - return 0; - else if (out < in) - return in - out; - else - return (buffer.length - out) + in; - } - - /** - * This methods closes the stream so that no more data can be read - * from it. - * - * @exception IOException If an error occurs - */ - public synchronized void close() throws IOException - { - closed = true; - // Wake any thread which may be in receive() waiting to write data. - notifyAll(); - } -} - |