1<?php
2/*
3 * Copyright 2008-2010 GuardTime AS
4 *
5 * This file is part of the GuardTime PHP SDK.
6 *
7 * Licensed under the Apache License, Version 2.0 (the "License");
8 * you may not use this file except in compliance with the License.
9 * You may obtain a copy of the License at
10 *
11 *     http://www.apache.org/licenses/LICENSE-2.0
12 *
13 * Unless required by applicable law or agreed to in writing, software
14 * distributed under the License is distributed on an "AS IS" BASIS,
15 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
16 * See the License for the specific language governing permissions and
17 * limitations under the License.
18 */
19
20/**
21 * @package asn1
22 */
23
24/**
25 * ASN.1 Null implementation.
26 *
27 * @package asn1
28 */
29class ASN1Null extends ASN1Object {
30
31    /**
32     * Constructs a new instance of ASN1Null.
33     * @return void
34     */
35    public function __construct() {
36    }
37
38    /**
39     * Encodes ASN1Null as DER byte array.
40     *
41     * @return array DER encoding of this ASN1Null
42     */
43    public function encodeDER() {
44
45        $bytes = array();
46
47        $this->append($bytes, ASN1DER::encodeType(ASN1_TAG_NULL));
48        $this->append($bytes, 0x0);
49
50        return $bytes;
51    }
52
53    /**
54     * Decodes an ASN1Null object.
55     *
56     * For ASN1Null the byte stream must be empty (no V bytes, just TL)
57     *
58     * @throws GTException
59     * @param  array $bytes null or empty array
60     * @return void
61     */
62    public function decodeDER($bytes) {
63
64        if (!empty($bytes)) {
65            throw new GTException("ASN1Null TLV should not contain any V bytes");
66        }
67    }
68}
69
70?>
71