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 jdk.incubator.http.internal.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 final class StringReader {

    39 

    40     private static final int NEW             = 0;

    41     private static final int FIRST_BYTE_READ = 1;

    42     private static final int LENGTH_READ     = 2;

    43     private static final int DONE            = 4;

    44 

    45     private final IntegerReader intReader = new IntegerReader();

    46     private final Huffman.Reader huffmanReader = new Huffman.Reader();

    47     private final ISO_8859_1.Reader plainReader = new ISO_8859_1.Reader();

    48 

    49     private int state = NEW;

    50 

    51     private boolean huffman;

    52     private int remainingLength;

    53 

    54     boolean read(ByteBuffer input, Appendable output) {

    55         if (state == DONE) {

    56             return true;

    57         }

    58         if (!input.hasRemaining()) {

    59             return false;

    60         }

    61         if (state == NEW) {

    62             int p = input.position();

    63             huffman = (input.get(p) & 0b10000000) != 0;

    64             state = FIRST_BYTE_READ;

    65             intReader.configure(7);

    66         }

    67         if (state == FIRST_BYTE_READ) {

    68             boolean lengthRead = intReader.read(input);

    69             if (!lengthRead) {

    70                 return false;

    71             }

    72             remainingLength = intReader.get();

    73             state = LENGTH_READ;

    74         }

    75         if (state == LENGTH_READ) {

    76             boolean isLast = input.remaining() >= remainingLength;

    77             int oldLimit = input.limit();

    78             if (isLast) {

    79                 input.limit(input.position() + remainingLength);

    80             }

    81             remainingLength -= Math.min(input.remaining(), remainingLength);

    82             if (huffman) {

    83                 huffmanReader.read(input, output, isLast);

    84             } else {

    85                 plainReader.read(input, output);

    86             }

    87             if (isLast) {

    88                 input.limit(oldLimit);

    89                 state = DONE;

    90             }

    91             return isLast;

    92         }

    93         throw new InternalError(Arrays.toString(

    94                 new Object[]{state, huffman, remainingLength}));

    95     }

    96 

    97     boolean isHuffmanEncoded() {

    98         if (state < FIRST_BYTE_READ) {

    99             throw new IllegalStateException("Has not been fully read yet");

   100         }

   101         return huffman;

   102     }

   103 

   104     void reset() {

   105         if (huffman) {

   106             huffmanReader.reset();

   107         } else {

   108             plainReader.reset();

   109         }

   110         intReader.reset();

   111         state = NEW;

   112     }

   113 }