1 /*

     2  * Copyright 2003-2007 Sun Microsystems, Inc.  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.  Sun designates this

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

     9  * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

    22  * CA 95054 USA or visit www.sun.com if you need additional information or

    23  * have any questions.

    24  */

    25 

    26 package sun.security.ssl;

    27 

    28 import java.io.*;

    29 import java.nio.*;

    30 

    31 /**

    32  * A simple InputStream which uses ByteBuffers as it's backing store.

    33  * <P>

    34  * The only IOException should come if the InputStream has been closed.

    35  * All other IOException should not occur because all the data is local.

    36  * Data reads on an exhausted ByteBuffer returns a -1.

    37  *

    38  * @author  Brad Wetmore

    39  */

    40 class ByteBufferInputStream extends InputStream {

    41 

    42     ByteBuffer bb;

    43 

    44     ByteBufferInputStream(ByteBuffer bb) {

    45         this.bb = bb;

    46     }

    47 

    48     /**

    49      * Returns a byte from the ByteBuffer.

    50      *

    51      * Increments position().

    52      */

    53     public int read() throws IOException {

    54 

    55         if (bb == null) {

    56             throw new IOException("read on a closed InputStream");

    57         }

    58 

    59         if (bb.remaining() == 0) {

    60             return -1;

    61         }

    62         return bb.get();

    63     }

    64 

    65     /**

    66      * Returns a byte array from the ByteBuffer.

    67      *

    68      * Increments position().

    69      */

    70     public int read(byte b[]) throws IOException {

    71 

    72         if (bb == null) {

    73             throw new IOException("read on a closed InputStream");

    74         }

    75 

    76         return read(b, 0, b.length);

    77     }

    78 

    79     /**

    80      * Returns a byte array from the ByteBuffer.

    81      *

    82      * Increments position().

    83      */

    84     public int read(byte b[], int off, int len) throws IOException {

    85 

    86         if (bb == null) {

    87             throw new IOException("read on a closed InputStream");

    88         }

    89 

    90         if (b == null) {

    91             throw new NullPointerException();

    92         } else if ((off < 0) || (off > b.length) || (len < 0) ||

    93                    ((off + len) > b.length) || ((off + len) < 0)) {

    94             throw new IndexOutOfBoundsException();

    95         } else if (len == 0) {

    96             return 0;

    97         }

    98 

    99         int length = Math.min(bb.remaining(), len);

   100         if (length == 0) {

   101             return -1;

   102         }

   103 

   104         bb.get(b, off, length);

   105         return length;

   106     }

   107 

   108     /**

   109      * Skips over and discards <code>n</code> bytes of data from this input

   110      * stream.

   111      */

   112     public long skip(long n) throws IOException {

   113 

   114         if (bb == null) {

   115             throw new IOException("skip on a closed InputStream");

   116         }

   117 

   118         if (n <= 0) {

   119             return 0;

   120         }

   121 

   122         /*

   123          * ByteBuffers have at most an int, so lose the upper bits.

   124          * The contract allows this.

   125          */

   126         int nInt = (int) n;

   127         int skip = Math.min(bb.remaining(), nInt);

   128 

   129         bb.position(bb.position() + skip);

   130 

   131         return nInt;

   132     }

   133 

   134     /**

   135      * Returns the number of bytes that can be read (or skipped over)

   136      * from this input stream without blocking by the next caller of a

   137      * method for this input stream.

   138      */

   139     public int available() throws IOException {

   140 

   141         if (bb == null) {

   142             throw new IOException("available on a closed InputStream");

   143         }

   144 

   145         return bb.remaining();

   146     }

   147 

   148     /**

   149      * Closes this input stream and releases any system resources associated

   150      * with the stream.

   151      *

   152      * @exception  IOException  if an I/O error occurs.

   153      */

   154     public void close() throws IOException {

   155         bb = null;

   156     }

   157 

   158     /**

   159      * Marks the current position in this input stream.

   160      */

   161     public synchronized void mark(int readlimit) {}

   162 

   163     /**

   164      * Repositions this stream to the position at the time the

   165      * <code>mark</code> method was last called on this input stream.

   166      */

   167     public synchronized void reset() throws IOException {

   168         throw new IOException("mark/reset not supported");

   169     }

   170 

   171     /**

   172      * Tests if this input stream supports the <code>mark</code> and

   173      * <code>reset</code> methods.

   174      */

   175     public boolean markSupported() {

   176         return false;

   177     }

   178 }