content: /*
   * Copyright (C) 2016 The Android Open Source Project
   *
   * Licensed under the Apache License, Version 2.0 (the "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   *
   *      http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  
  package com.android.server.wifi.hotspot2.anqp;
  
  import com.android.internal.annotations.VisibleForTesting;
  
  import java.net.ProtocolException;
  import java.nio.BufferUnderflowException;
  import java.nio.ByteBuffer;
  import java.util.ArrayList;
  import java.util.Collections;
  import java.util.List;
  
  
  /**
   * The 3GPP Cellular Network ANQP Element, IEEE802.11-2012 section 8.4.4.11.
   * The value is embedded in a Generic container User Data (GUD).
   * Refer to Annex A of 3GPP TS 24.234 version 11.3.0 for more info:
   * (http://www.etsi.org/deliver/etsi_ts/124200_124299/124234/11.03.00_60/ts_124234v110300p.pdf).
   *
   * Format:
   * | GUD Version | Length | IEI 1 | ... | IEI N|
   *        1           1    variable
   *
   */
  public class ThreeGPPNetworkElement extends ANQPElement {
      /**
       * The expected protocol version number of the Generic container User Data (GUD).
       */
      @VisibleForTesting
      public static final int GUD_VERSION_1 = 0;
  
      private final List<CellularNetwork> mNetworks;
  
      @VisibleForTesting
      public ThreeGPPNetworkElement(List<CellularNetwork> networks) {
          super(Constants.ANQPElementType.ANQP3GPPNetwork);
          mNetworks = networks;
      }
  
      /**
       * Parse a ThreeGPPNetworkElement from the given buffer.
       *
       * @param payload The byte buffer to read from
       * @return {@link ThreeGPPNetworkElement}
       * @throws BufferUnderflowException
       * @throws ProtocolException
       */
      public static ThreeGPPNetworkElement parse(ByteBuffer payload)
              throws ProtocolException {
          // Verify version.
          int gudVersion = payload.get() & 0xFF;
          if (gudVersion != GUD_VERSION_1) {
              throw new ProtocolException("Unsupported GUD version: " + gudVersion);
          }
  
          // Verify length.
          int length = payload.get() & 0xFF;
          if (length != payload.remaining()) {
              throw new ProtocolException("Mismatch length and buffer size: length=" + length
                      + " bufferSize=" + payload.remaining());
          }
  
          // Parse each IEI (Information Element Identity) content.
          List<CellularNetwork> networks = new ArrayList<>();
          while (payload.hasRemaining()) {
              CellularNetwork network = CellularNetwork.parse(payload);
              if (network != null) {
                  networks.add(network);
              }
          }
          return new ThreeGPPNetworkElement(networks);
      }
  
      public List<CellularNetwork> getNetworks() {
          return Collections.unmodifiableList(mNetworks);
      }
  
      @Override
      public boolean equals(Object thatObject) {
          if (this == thatObject) {
              return true;
          }
          if (!(thatObject instanceof ThreeGPPNetworkElement)) {
              return false;
          }
          ThreeGPPNetworkElement that = (ThreeGPPNetworkElement) thatObject;
          return mNetworks.equals(that.mNetworks);
  
      }
  
      @Override
      public int hashCode() {
          return mNetworks.hashCode();
      }
  
      @Override
      public String toString() {
          return "ThreeGPPNetwork{mNetworks=" + mNetworks + "}";
      }
  }
  