1/*
2 * Copyright (C) 2006 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17package com.android.internal.telephony.cat;
18
19import java.util.List;
20
21/**
22 * Class for representing BER-TLV objects.
23 *
24 * @see "ETSI TS 102 223 Annex C" for more information.
25 *
26 * {@hide}
27 */
28class BerTlv {
29    private int mTag = BER_UNKNOWN_TAG;
30    private List<ComprehensionTlv> mCompTlvs = null;
31
32    public static final int BER_UNKNOWN_TAG             = 0x00;
33    public static final int BER_PROACTIVE_COMMAND_TAG   = 0xd0;
34    public static final int BER_MENU_SELECTION_TAG      = 0xd3;
35    public static final int BER_EVENT_DOWNLOAD_TAG      = 0xd6;
36
37    private BerTlv(int tag, List<ComprehensionTlv> ctlvs) {
38        mTag = tag;
39        mCompTlvs = ctlvs;
40    }
41
42    /**
43     * Gets a list of ComprehensionTlv objects contained in this BER-TLV object.
44     *
45     * @return A list of COMPREHENSION-TLV object
46     */
47    public List<ComprehensionTlv> getComprehensionTlvs() {
48        return mCompTlvs;
49    }
50
51    /**
52     * Gets a tag id of the BER-TLV object.
53     *
54     * @return A tag integer.
55     */
56    public int getTag() {
57        return mTag;
58    }
59
60    /**
61     * Decodes a BER-TLV object from a byte array.
62     *
63     * @param data A byte array to decode from
64     * @return A BER-TLV object decoded
65     * @throws ResultException
66     */
67    public static BerTlv decode(byte[] data) throws ResultException {
68        int curIndex = 0;
69        int endIndex = data.length;
70        int tag, length = 0;
71
72        try {
73            /* tag */
74            tag = data[curIndex++] & 0xff;
75            if (tag == BER_PROACTIVE_COMMAND_TAG) {
76                /* length */
77                int temp = data[curIndex++] & 0xff;
78                if (temp < 0x80) {
79                    length = temp;
80                } else if (temp == 0x81) {
81                    temp = data[curIndex++] & 0xff;
82                    if (temp < 0x80) {
83                        throw new ResultException(
84                                ResultCode.CMD_DATA_NOT_UNDERSTOOD,
85                                "length < 0x80 length=" + Integer.toHexString(length) +
86                                " curIndex=" + curIndex + " endIndex=" + endIndex);
87
88                    }
89                    length = temp;
90                } else {
91                    throw new ResultException(
92                            ResultCode.CMD_DATA_NOT_UNDERSTOOD,
93                            "Expected first byte to be length or a length tag and < 0x81" +
94                            " byte= " + Integer.toHexString(temp) + " curIndex=" + curIndex +
95                            " endIndex=" + endIndex);
96                }
97            } else {
98                if (ComprehensionTlvTag.COMMAND_DETAILS.value() == (tag & ~0x80)) {
99                    tag = BER_UNKNOWN_TAG;
100                    curIndex = 0;
101                }
102            }
103        } catch (IndexOutOfBoundsException e) {
104            throw new ResultException(ResultCode.REQUIRED_VALUES_MISSING,
105                    "IndexOutOfBoundsException " +
106                    " curIndex=" + curIndex + " endIndex=" + endIndex);
107        } catch (ResultException e) {
108            throw new ResultException(ResultCode.CMD_DATA_NOT_UNDERSTOOD, e.explanation());
109        }
110
111        /* COMPREHENSION-TLVs */
112        if (endIndex - curIndex < length) {
113            throw new ResultException(ResultCode.CMD_DATA_NOT_UNDERSTOOD,
114                    "Command had extra data endIndex=" + endIndex + " curIndex=" + curIndex +
115                    " length=" + length);
116        }
117
118        List<ComprehensionTlv> ctlvs = ComprehensionTlv.decodeMany(data,
119                curIndex);
120
121        return new BerTlv(tag, ctlvs);
122    }
123}
124