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    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   }

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