1 /*

     2  * Copyright (c) 2015, 2016, 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 package sun.net.httpclient.hpack;

    26 

    27 import java.nio.ByteBuffer;

    28 import java.util.Arrays;

    29 

    30 //

    31 //          0   1   2   3   4   5   6   7

    32 //        +---+---+---+---+---+---+---+---+

    33 //        | H |    String Length (7+)     |

    34 //        +---+---------------------------+

    35 //        |  String Data (Length octets)  |

    36 //        +-------------------------------+

    37 //

    38 // StringWriter does not require a notion of endOfInput (isLast) in 'write'

    39 // methods due to the nature of string representation in HPACK. Namely, the

    40 // length of the string is put before string's contents. Therefore the length is

    41 // always known beforehand.

    42 //

    43 // Expected use:

    44 //

    45 //     configure write* (reset configure write*)*

    46 //

    47 final class StringWriter {

    48 

    49     private static final int NEW            = 0;

    50     private static final int CONFIGURED     = 1;

    51     private static final int LENGTH_WRITTEN = 2;

    52     private static final int DONE           = 4;

    53 

    54     private final IntegerWriter intWriter = new IntegerWriter();

    55     private final Huffman.Writer huffmanWriter = new Huffman.Writer();

    56     private final ISO_8859_1.Writer plainWriter = new ISO_8859_1.Writer();

    57 

    58     private int state = NEW;

    59     private boolean huffman;

    60 

    61     StringWriter configure(CharSequence input, boolean huffman) {

    62         return configure(input, 0, input.length(), huffman);

    63     }

    64 

    65     StringWriter configure(CharSequence input, int start, int end,

    66                            boolean huffman) {

    67         if (start < 0 || end < 0 || end > input.length() || start > end) {

    68             throw new IndexOutOfBoundsException(

    69                     String.format("input.length()=%s, start=%s, end=%s",

    70                             input.length(), start, end));

    71         }

    72         if (!huffman) {

    73             plainWriter.configure(input, start, end);

    74             intWriter.configure(end - start, 7, 0b0000_0000);

    75         } else {

    76             huffmanWriter.from(input, start, end);

    77             intWriter.configure(Huffman.INSTANCE.lengthOf(input, start, end),

    78                     7, 0b1000_0000);

    79         }

    80 

    81         this.huffman = huffman;

    82         state = CONFIGURED;

    83         return this;

    84     }

    85 

    86     boolean write(ByteBuffer output) {

    87         if (state == DONE) {

    88             return true;

    89         }

    90         if (state == NEW) {

    91             throw new IllegalStateException("Configure first");

    92         }

    93         if (!output.hasRemaining()) {

    94             return false;

    95         }

    96         if (state == CONFIGURED) {

    97             if (intWriter.write(output)) {

    98                 state = LENGTH_WRITTEN;

    99             } else {

   100                 return false;

   101             }

   102         }

   103         if (state == LENGTH_WRITTEN) {

   104             boolean written = huffman

   105                     ? huffmanWriter.write(output)

   106                     : plainWriter.write(output);

   107             if (written) {

   108                 state = DONE;

   109                 return true;

   110             } else {

   111                 return false;

   112             }

   113         }

   114         throw new InternalError(Arrays.toString(new Object[]{state, huffman}));

   115     }

   116 

   117     void reset() {

   118         intWriter.reset();

   119         if (huffman) {

   120             huffmanWriter.reset();

   121         } else {

   122             plainWriter.reset();

   123         }

   124         state = NEW;

   125     }

   126 }