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      1 /*
      2  * Copyright (C) 2011 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.server.net;
     18 
     19 import android.net.NetworkIdentity;
     20 
     21 import java.io.DataInputStream;
     22 import java.io.DataOutputStream;
     23 import java.io.IOException;
     24 import java.util.HashSet;
     25 
     26 /**
     27  * Identity of a {@code iface}, defined by the set of {@link NetworkIdentity}
     28  * active on that interface.
     29  *
     30  * @hide
     31  */
     32 public class NetworkIdentitySet extends HashSet<NetworkIdentity> implements
     33         Comparable<NetworkIdentitySet> {
     34     private static final int VERSION_INIT = 1;
     35     private static final int VERSION_ADD_ROAMING = 2;
     36     private static final int VERSION_ADD_NETWORK_ID = 3;
     37 
     38     public NetworkIdentitySet() {
     39     }
     40 
     41     public NetworkIdentitySet(DataInputStream in) throws IOException {
     42         final int version = in.readInt();
     43         final int size = in.readInt();
     44         for (int i = 0; i < size; i++) {
     45             if (version <= VERSION_INIT) {
     46                 final int ignored = in.readInt();
     47             }
     48             final int type = in.readInt();
     49             final int subType = in.readInt();
     50             final String subscriberId = readOptionalString(in);
     51             final String networkId;
     52             if (version >= VERSION_ADD_NETWORK_ID) {
     53                 networkId = readOptionalString(in);
     54             } else {
     55                 networkId = null;
     56             }
     57             final boolean roaming;
     58             if (version >= VERSION_ADD_ROAMING) {
     59                 roaming = in.readBoolean();
     60             } else {
     61                 roaming = false;
     62             }
     63 
     64             add(new NetworkIdentity(type, subType, subscriberId, networkId, false));
     65         }
     66     }
     67 
     68     public void writeToStream(DataOutputStream out) throws IOException {
     69         out.writeInt(VERSION_ADD_NETWORK_ID);
     70         out.writeInt(size());
     71         for (NetworkIdentity ident : this) {
     72             out.writeInt(ident.getType());
     73             out.writeInt(ident.getSubType());
     74             writeOptionalString(out, ident.getSubscriberId());
     75             writeOptionalString(out, ident.getNetworkId());
     76             out.writeBoolean(ident.getRoaming());
     77         }
     78     }
     79 
     80     private static void writeOptionalString(DataOutputStream out, String value) throws IOException {
     81         if (value != null) {
     82             out.writeByte(1);
     83             out.writeUTF(value);
     84         } else {
     85             out.writeByte(0);
     86         }
     87     }
     88 
     89     private static String readOptionalString(DataInputStream in) throws IOException {
     90         if (in.readByte() != 0) {
     91             return in.readUTF();
     92         } else {
     93             return null;
     94         }
     95     }
     96 
     97     @Override
     98     public int compareTo(NetworkIdentitySet another) {
     99         if (isEmpty()) return -1;
    100         if (another.isEmpty()) return 1;
    101 
    102         final NetworkIdentity ident = iterator().next();
    103         final NetworkIdentity anotherIdent = another.iterator().next();
    104         return ident.compareTo(anotherIdent);
    105     }
    106 }
    107