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/*
 * Copyright (c) 1995, 2021, Oracle and/or its affiliates. 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.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
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 */

package java.net;

import java.io.FileDescriptor;
import java.io.FileInputStream;
import java.io.IOException;
import java.nio.channels.FileChannel;

import sun.net.ConnectionResetException;

/**
 * This stream extends FileInputStream to implement a
 * SocketInputStream. Note that this class should NOT be
 * public.
 *
 * @author      Jonathan Payne
 * @author      Arthur van Hoff
 */
class SocketInputStream extends FileInputStream {
    static {
        init();
    }

    private boolean eof;
    private AbstractPlainSocketImpl impl = null;
    private byte temp[];

    /**
     * Creates a new SocketInputStream. Can only be called
     * by a Socket. This method needs to hang on to the owner Socket so
     * that the fd will not be closed.
     * @param impl the implemented socket input stream
     */
    SocketInputStream(AbstractPlainSocketImpl impl) throws IOException {
        super(impl.getFileDescriptor());
        this.impl = impl;
    }

    /**
     * Returns the unique {@link java.nio.channels.FileChannel FileChannel}
     * object associated with this file input stream.

* * The {@code getChannel} method of {@code SocketInputStream} * returns {@code null} since it is a socket based stream.

* * @return the file channel associated with this file input stream * * @since 1.4 */ public final FileChannel getChannel() { return null; } /** * Reads into an array of bytes at the specified offset using * the received socket primitive. * @param fd the FileDescriptor * @param b the buffer into which the data is read * @param off the start offset of the data * @param len the maximum number of bytes read * @param timeout the read timeout in ms * @return the actual number of bytes read, -1 is * returned when the end of the stream is reached. * @throws IOException If an I/O error has occurred. */ private native int socketRead0(FileDescriptor fd, byte b[], int off, int len, int timeout) throws IOException; // wrap native call to allow instrumentation /** * Reads into an array of bytes at the specified offset using * the received socket primitive. * @param fd the FileDescriptor * @param b the buffer into which the data is read * @param off the start offset of the data * @param len the maximum number of bytes read * @param timeout the read timeout in ms * @return the actual number of bytes read, -1 is * returned when the end of the stream is reached. * @throws IOException If an I/O error has occurred. */ private int socketRead(FileDescriptor fd, byte b[], int off, int len, int timeout) throws IOException { return socketRead0(fd, b, off, len, timeout); } /** * Reads into a byte array data from the socket. * @param b the buffer into which the data is read * @return the actual number of bytes read, -1 is * returned when the end of the stream is reached. * @throws IOException If an I/O error has occurred. */ public int read(byte b[]) throws IOException { return read(b, 0, b.length); } /** * Reads into a byte array b at offset off, * length bytes of data. * @param b the buffer into which the data is read * @param off the start offset of the data * @param length the maximum number of bytes read * @return the actual number of bytes read, -1 is * returned when the end of the stream is reached. * @throws IOException If an I/O error has occurred. */ public int read(byte b[], int off, int length) throws IOException { return read(b, off, length, impl.getTimeout()); } int read(byte b[], int off, int length, int timeout) throws IOException { int n; // EOF already encountered if (eof) { return -1; } // connection reset if (impl.isConnectionReset()) { throw new SocketException("Connection reset"); } // bounds check if (length <= 0 || off < 0 || length > b.length - off) { if (length == 0) { return 0; } throw new ArrayIndexOutOfBoundsException("length == " + length + " off == " + off + " buffer length == " + b.length); } // acquire file descriptor and do the read FileDescriptor fd = impl.acquireFD(); try { n = socketRead(fd, b, off, length, timeout); if (n > 0) { return n; } } catch (ConnectionResetException rstExc) { impl.setConnectionReset(); } finally { impl.releaseFD(); } /* * If we get here we are at EOF, the socket has been closed, * or the connection has been reset. */ if (impl.isClosedOrPending()) { throw new SocketException("Socket closed"); } if (impl.isConnectionReset()) { throw new SocketException("Connection reset"); } eof = true; return -1; } /** * Reads a single byte from the socket. */ public int read() throws IOException { if (eof) { return -1; } temp = new byte[1]; int n = read(temp, 0, 1); if (n <= 0) { return -1; } return temp[0] & 0xff; } /** * Skips n bytes of input. * @param numbytes the number of bytes to skip * @return the actual number of bytes skipped. * @throws IOException If an I/O error has occurred. */ public long skip(long numbytes) throws IOException { if (numbytes <= 0) { return 0; } long n = numbytes; int buflen = (int) Math.min(1024, n); byte data[] = new byte[buflen]; while (n > 0) { int r = read(data, 0, (int) Math.min((long) buflen, n)); if (r < 0) { break; } n -= r; } return numbytes - n; } /** * Returns the number of bytes that can be read without blocking. * @return the number of immediately available bytes */ public int available() throws IOException { int available = impl.available(); return eof ? 0 : available; } void setEOF(boolean eof) { this.eof = eof; } public void close() throws IOException { // No longer used. Socket.getInputStream returns an // InputStream which calls Socket.close directly assert false; } /** * Perform class load-time initializations. */ private static native void init(); }




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