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      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 
     17 package com.android.internal.telephony.cat;
     18 
     19 import 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  */
     28 class 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                     }
     86                     length = temp;
     87                 } else {
     88                     throw new ResultException(
     89                             ResultCode.CMD_DATA_NOT_UNDERSTOOD);
     90                 }
     91             } else {
     92                 if (ComprehensionTlvTag.COMMAND_DETAILS.value() == (tag & ~0x80)) {
     93                     tag = BER_UNKNOWN_TAG;
     94                     curIndex = 0;
     95                 }
     96             }
     97         } catch (IndexOutOfBoundsException e) {
     98             throw new ResultException(ResultCode.REQUIRED_VALUES_MISSING);
     99         } catch (ResultException e) {
    100             throw new ResultException(ResultCode.CMD_DATA_NOT_UNDERSTOOD);
    101         }
    102 
    103         /* COMPREHENSION-TLVs */
    104         if (endIndex - curIndex < length) {
    105             throw new ResultException(ResultCode.CMD_DATA_NOT_UNDERSTOOD);
    106         }
    107 
    108         List<ComprehensionTlv> ctlvs = ComprehensionTlv.decodeMany(data,
    109                 curIndex);
    110 
    111         return new BerTlv(tag, ctlvs);
    112     }
    113 }
    114