1 /*

     2  * Copyright (c) 2001, 2002, Oracle and/or its affiliates. All rights reserved.

     3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

     4  *

     5  * This code is free software; you can redistribute it and/or modify it

     6  * under the terms of the GNU General Public License version 2 only, as

     7  * published by the Free Software Foundation.  Oracle designates this

     8  * particular file as subject to the "Classpath" exception as provided

     9  * by Oracle in the LICENSE file that accompanied this code.

    10  *

    11  * This code is distributed in the hope that it will be useful, but WITHOUT

    12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

    13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

    14  * version 2 for more details (a copy is included in the LICENSE file that

    15  * accompanied this code).

    16  *

    17  * You should have received a copy of the GNU General Public License version

    18  * 2 along with this work; if not, write to the Free Software Foundation,

    19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

    20  *

    21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

    22  * or visit www.oracle.com if you need additional information or have any

    23  * questions.

    24  */

    25 

    26 package sun.nio.ch;

    27 

    28 import java.io.*;

    29 import java.nio.*;

    30 import java.nio.channels.*;

    31 import java.nio.channels.spi.*;

    32 

    33 

    34 /**

    35  * This class is defined here rather than in java.nio.channels.Channels

    36  * so that code can be shared with SocketAdaptor.

    37  *

    38  * @author Mike McCloskey

    39  * @author Mark Reinhold

    40  * @since 1.4

    41  */

    42 

    43 public class ChannelInputStream

    44     extends InputStream

    45 {

    46 

    47     public static int read(ReadableByteChannel ch, ByteBuffer bb,

    48                            boolean block)

    49         throws IOException

    50     {

    51         if (ch instanceof SelectableChannel) {

    52             SelectableChannel sc = (SelectableChannel)ch;

    53             synchronized (sc.blockingLock()) {

    54                 boolean bm = sc.isBlocking();

    55                 if (!bm)

    56                     throw new IllegalBlockingModeException();

    57                 if (bm != block)

    58                     sc.configureBlocking(block);

    59                 int n = ch.read(bb);

    60                 if (bm != block)

    61                     sc.configureBlocking(bm);

    62                 return n;

    63             }

    64         } else {

    65             return ch.read(bb);

    66         }

    67     }

    68 

    69     protected final ReadableByteChannel ch;

    70     private ByteBuffer bb = null;

    71     private byte[] bs = null;           // Invoker's previous array

    72     private byte[] b1 = null;

    73 

    74     public ChannelInputStream(ReadableByteChannel ch) {

    75         this.ch = ch;

    76     }

    77 

    78     public synchronized int read() throws IOException {

    79         if (b1 == null)

    80             b1 = new byte[1];

    81         int n = this.read(b1);

    82         if (n == 1)

    83             return b1[0] & 0xff;

    84         return -1;

    85     }

    86 

    87     public synchronized int read(byte[] bs, int off, int len)

    88         throws IOException

    89     {

    90         if ((off < 0) || (off > bs.length) || (len < 0) ||

    91             ((off + len) > bs.length) || ((off + len) < 0)) {

    92             throw new IndexOutOfBoundsException();

    93         } else if (len == 0)

    94             return 0;

    95 

    96         ByteBuffer bb = ((this.bs == bs)

    97                          ? this.bb

    98                          : ByteBuffer.wrap(bs));

    99         bb.limit(Math.min(off + len, bb.capacity()));

   100         bb.position(off);

   101         this.bb = bb;

   102         this.bs = bs;

   103         return read(bb);

   104     }

   105 

   106     protected int read(ByteBuffer bb)

   107         throws IOException

   108     {

   109         return ChannelInputStream.read(ch, bb, true);

   110     }

   111 

   112     public int available() throws IOException {

   113         // special case where the channel is to a file

   114         if (ch instanceof SeekableByteChannel) {

   115             SeekableByteChannel sbc = (SeekableByteChannel)ch;

   116             long rem = Math.max(0, sbc.size() - sbc.position());

   117             return (rem > Integer.MAX_VALUE) ? Integer.MAX_VALUE : (int)rem;

   118         }

   119         return 0;

   120     }

   121 

   122     public void close() throws IOException {

   123         ch.close();

   124     }

   125 

   126 }