1 /*

     2  * Copyright (c) 2003, 2014, 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.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     @Override

    54     public int read() throws IOException {

    55 

    56         if (bb == null) {

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

    58         }

    59 

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

    61             return -1;

    62         }

    63 

    64         return (bb.get() & 0xFF);   // need to be in the range 0 to 255

    65     }

    66 

    67     /**

    68      * Returns a byte array from the ByteBuffer.

    69      *

    70      * Increments position().

    71      */

    72     @Override

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

    74 

    75         if (bb == null) {

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

    77         }

    78 

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

    80     }

    81 

    82     /**

    83      * Returns a byte array from the ByteBuffer.

    84      *

    85      * Increments position().

    86      */

    87     @Override

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

    89 

    90         if (bb == null) {

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

    92         }

    93 

    94         if (b == null) {

    95             throw new NullPointerException();

    96         } else if (off < 0 || len < 0 || len > b.length - off) {

    97             throw new IndexOutOfBoundsException();

    98         } else if (len == 0) {

    99             return 0;

   100         }

   101 

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

   103         if (length == 0) {

   104             return -1;

   105         }

   106 

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

   108         return length;

   109     }

   110 

   111     /**

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

   113      * stream.

   114      */

   115     @Override

   116     public long skip(long n) throws IOException {

   117 

   118         if (bb == null) {

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

   120         }

   121 

   122         if (n <= 0) {

   123             return 0;

   124         }

   125 

   126         /*

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

   128          * The contract allows this.

   129          */

   130         int nInt = (int) n;

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

   132 

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

   134 

   135         return nInt;

   136     }

   137 

   138     /**

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

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

   141      * method for this input stream.

   142      */

   143     @Override

   144     public int available() throws IOException {

   145 

   146         if (bb == null) {

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

   148         }

   149 

   150         return bb.remaining();

   151     }

   152 

   153     /**

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

   155      * with the stream.

   156      *

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

   158      */

   159     @Override

   160     public void close() throws IOException {

   161         bb = null;

   162     }

   163 

   164     /**

   165      * Marks the current position in this input stream.

   166      */

   167     @Override

   168     public synchronized void mark(int readlimit) {}

   169 

   170     /**

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

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

   173      */

   174     @Override

   175     public synchronized void reset() throws IOException {

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

   177     }

   178 

   179     /**

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

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

   182      */

   183     @Override

   184     public boolean markSupported() {

   185         return false;

   186     }

   187 }