content: /*
   * Copyright (C) 2017 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.util;
  
  import android.text.TextUtils;
  
  import com.android.server.wifi.ByteBufferReader;
  
  import libcore.util.HexEncoding;
  
  import java.nio.BufferUnderflowException;
  import java.nio.ByteBuffer;
  import java.nio.ByteOrder;
  import java.nio.CharBuffer;
  import java.nio.charset.CharacterCodingException;
  import java.nio.charset.CharsetDecoder;
  import java.nio.charset.CharsetEncoder;
  import java.nio.charset.StandardCharsets;
  import java.util.ArrayList;
  import java.util.Arrays;
  
  /**
   * Provide utility functions for native interfacing modules.
   */
  public class NativeUtil {
      private static final String ANY_MAC_STR = "any";
      public static final byte[] ANY_MAC_BYTES = {0, 0, 0, 0, 0, 0};
      private static final int MAC_LENGTH = 6;
      private static final int MAC_OUI_LENGTH = 3;
      private static final int MAC_STR_LENGTH = MAC_LENGTH * 2 + 5;
      private static final int SSID_BYTES_MAX_LEN = 32;
  
      /**
       * Convert the string to byte array list.
       *
       * @return the UTF_8 char byte values of str, as an ArrayList.
       * @throws IllegalArgumentException if a null or unencodable string is sent.
       */
      public static ArrayList<Byte> stringToByteArrayList(String str) {
          if (str == null) {
              throw new IllegalArgumentException("null string");
          }
          // Ensure that the provided string is UTF_8 encoded.
          CharsetEncoder encoder = StandardCharsets.UTF_8.newEncoder();
          try {
              ByteBuffer encoded = encoder.encode(CharBuffer.wrap(str));
              byte[] byteArray = new byte[encoded.remaining()];
              encoded.get(byteArray);
              return byteArrayToArrayList(byteArray);
          } catch (CharacterCodingException cce) {
              throw new IllegalArgumentException("cannot be utf-8 encoded", cce);
          }
      }
  
      /**
       * Convert the byte array list to string.
       *
       * @return the string decoded from UTF_8 byte values in byteArrayList.
       * @throws IllegalArgumentException if a null byte array list is sent.
       */
      public static String stringFromByteArrayList(ArrayList<Byte> byteArrayList) {
          if (byteArrayList == null) {
              throw new IllegalArgumentException("null byte array list");
          }
          byte[] byteArray = new byte[byteArrayList.size()];
          int i = 0;
          for (Byte b : byteArrayList) {
              byteArray[i] = b;
              i++;
          }
          return new String(byteArray, StandardCharsets.UTF_8);
      }
  
      /**
       * Convert the string to byte array.
       *
       * @return the UTF_8 char byte values of str, as an Array.
       * @throws IllegalArgumentException if a null string is sent.
       */
      public static byte[] stringToByteArray(String str) {
          if (str == null) {
              throw new IllegalArgumentException("null string");
          }
          return str.getBytes(StandardCharsets.UTF_8);
      }
  
      /**
       * Convert the byte array list to string.
       *
       * @return the string decoded from UTF_8 byte values in byteArray.
       * @throws IllegalArgumentException if a null byte array is sent.
       */
      public static String stringFromByteArray(byte[] byteArray) {
          if (byteArray == null) {
              throw new IllegalArgumentException("null byte array");
          }
          return new String(byteArray);
      }
  
      /**
       * Converts a mac address string to an array of Bytes.
       *
       * @param macStr string of format: "XX:XX:XX:XX:XX:XX" or "XXXXXXXXXXXX", where X is any
       *        hexadecimal digit.
       *        Passing null, empty string or "any" is the same as 00:00:00:00:00:00
       * @throws IllegalArgumentException for various malformed inputs.
       */
      public static byte[] macAddressToByteArray(String macStr) {
          if (TextUtils.isEmpty(macStr) || ANY_MAC_STR.equals(macStr)) return ANY_MAC_BYTES;
          String cleanMac = macStr.replace(":", "");
          if (cleanMac.length() != MAC_LENGTH * 2) {
              throw new IllegalArgumentException("invalid mac string length: " + cleanMac);
          }
          return HexEncoding.decode(cleanMac.toCharArray(), false);
      }
  
      /**
       * Converts an array of 6 bytes to a HexEncoded String with format: "XX:XX:XX:XX:XX:XX", where X
       * is any hexadecimal digit.
       *
       * @param macArray byte array of mac values, must have length 6
       * @throws IllegalArgumentException for malformed inputs.
       */
      public static String macAddressFromByteArray(byte[] macArray) {
          if (macArray == null) {
              throw new IllegalArgumentException("null mac bytes");
          }
          if (macArray.length != MAC_LENGTH) {
              throw new IllegalArgumentException("invalid macArray length: " + macArray.length);
          }
          StringBuilder sb = new StringBuilder(MAC_STR_LENGTH);
          for (int i = 0; i < macArray.length; i++) {
              if (i != 0) sb.append(":");
              sb.append(new String(HexEncoding.encode(macArray, i, 1)));
          }
          return sb.toString().toLowerCase();
      }
  
      /**
       * Converts a mac address OUI string to an array of Bytes.
       *
       * @param macStr string of format: "XX:XX:XX" or "XXXXXX", where X is any hexadecimal digit.
       * @throws IllegalArgumentException for various malformed inputs.
       */
      public static byte[] macAddressOuiToByteArray(String macStr) {
          if (macStr == null) {
              throw new IllegalArgumentException("null mac string");
          }
          String cleanMac = macStr.replace(":", "");
          if (cleanMac.length() != MAC_OUI_LENGTH * 2) {
              throw new IllegalArgumentException("invalid mac oui string length: " + cleanMac);
          }
          return HexEncoding.decode(cleanMac.toCharArray(), false);
      }
  
      /**
       * Converts an array of 6 bytes to a long representing the MAC address.
       *
       * @param macArray byte array of mac values, must have length 6
       * @return Long value of the mac address.
       * @throws IllegalArgumentException for malformed inputs.
       */
      public static Long macAddressToLong(byte[] macArray) {
          if (macArray == null) {
              throw new IllegalArgumentException("null mac bytes");
          }
          if (macArray.length != MAC_LENGTH) {
              throw new IllegalArgumentException("invalid macArray length: " + macArray.length);
          }
          try {
              return ByteBufferReader.readInteger(
                      ByteBuffer.wrap(macArray), ByteOrder.BIG_ENDIAN, macArray.length);
          } catch (BufferUnderflowException | IllegalArgumentException e) {
              throw new IllegalArgumentException("invalid macArray");
          }
      }
  
      /**
       * Remove enclosing quotes from the provided string.
       *
       * @param quotedStr String to be unquoted.
       * @return String without the enclosing quotes.
       */
      public static String removeEnclosingQuotes(String quotedStr) {
          int length = quotedStr.length();
          if ((length >= 2)
                  && (quotedStr.charAt(0) == '"') && (quotedStr.charAt(length - 1) == '"')) {
              return quotedStr.substring(1, length - 1);
          }
          return quotedStr;
      }
  
      /**
       * Add enclosing quotes to the provided string.
       *
       * @param str String to be quoted.
       * @return String with the enclosing quotes.
       */
      public static String addEnclosingQuotes(String str) {
          return "\"" + str + "\"";
      }
  
      /**
       * Converts an string to an arraylist of UTF_8 byte values.
       * These forms are acceptable:
       * a) UTF-8 String encapsulated in quotes, or
       * b) Hex string with no delimiters.
       *
       * @param str String to be converted.
       * @throws IllegalArgumentException for null string.
       */
      public static ArrayList<Byte> hexOrQuotedStringToBytes(String str) {
          if (str == null) {
              throw new IllegalArgumentException("null string");
          }
          int length = str.length();
          if ((length > 1) && (str.charAt(0) == '"') && (str.charAt(length - 1) == '"')) {
              str = str.substring(1, str.length() - 1);
              return stringToByteArrayList(str);
          } else {
              return byteArrayToArrayList(hexStringToByteArray(str));
          }
      }
  
      /**
       * Converts an ArrayList<Byte> of UTF_8 byte values to string.
       * The string will either be:
       * a) UTF-8 String encapsulated in quotes (if all the bytes are UTF-8 encodeable and non null),
       * or
       * b) Hex string with no delimiters.
       *
       * @param bytes List of bytes for ssid.
       * @throws IllegalArgumentException for null bytes.
       */
      public static String bytesToHexOrQuotedString(ArrayList<Byte> bytes) {
          if (bytes == null) {
              throw new IllegalArgumentException("null ssid bytes");
          }
          byte[] byteArray = byteArrayFromArrayList(bytes);
          // Check for 0's in the byte stream in which case we cannot convert this into a string.
          if (!bytes.contains(Byte.valueOf((byte) 0))) {
              CharsetDecoder decoder = StandardCharsets.UTF_8.newDecoder();
              try {
                  CharBuffer decoded = decoder.decode(ByteBuffer.wrap(byteArray));
                  return "\"" + decoded.toString() + "\"";
              } catch (CharacterCodingException cce) {
              }
          }
          return hexStringFromByteArray(byteArray);
      }
  
      /**
       * Converts an ssid string to an arraylist of UTF_8 byte values.
       * These forms are acceptable:
       * a) UTF-8 String encapsulated in quotes, or
       * b) Hex string with no delimiters.
       *
       * @param ssidStr String to be converted.
       * @throws IllegalArgumentException for null string.
       */
      public static ArrayList<Byte> decodeSsid(String ssidStr) {
          ArrayList<Byte> ssidBytes = hexOrQuotedStringToBytes(ssidStr);
          if (ssidBytes.size() > SSID_BYTES_MAX_LEN) {
              throw new IllegalArgumentException("ssid bytes size out of range: " + ssidBytes.size());
          }
          return ssidBytes;
      }
  
      /**
       * Converts an ArrayList<Byte> of UTF_8 byte values to ssid string.
       * The string will either be:
       * a) UTF-8 String encapsulated in quotes (if all the bytes are UTF-8 encodeable and non null),
       * or
       * b) Hex string with no delimiters.
       *
       * @param ssidBytes List of bytes for ssid.
       * @throws IllegalArgumentException for null bytes.
       */
      public static String encodeSsid(ArrayList<Byte> ssidBytes) {
          if (ssidBytes.size() > SSID_BYTES_MAX_LEN) {
              throw new IllegalArgumentException("ssid bytes size out of range: " + ssidBytes.size());
          }
          return bytesToHexOrQuotedString(ssidBytes);
      }
  
      /**
       * Convert from an array of primitive bytes to an array list of Byte.
       */
      public static ArrayList<Byte> byteArrayToArrayList(byte[] bytes) {
          ArrayList<Byte> byteList = new ArrayList<>();
          for (Byte b : bytes) {
              byteList.add(b);
          }
          return byteList;
      }
  
      /**
       * Convert from an array list of Byte to an array of primitive bytes.
       */
      public static byte[] byteArrayFromArrayList(ArrayList<Byte> bytes) {
          byte[] byteArray = new byte[bytes.size()];
          int i = 0;
          for (Byte b : bytes) {
              byteArray[i++] = b;
          }
          return byteArray;
      }
  
      /**
       * Converts a hex string to byte array.
       *
       * @param hexStr String to be converted.
       * @throws IllegalArgumentException for null string.
       */
      public static byte[] hexStringToByteArray(String hexStr) {
          if (hexStr == null) {
              throw new IllegalArgumentException("null hex string");
          }
          return HexEncoding.decode(hexStr.toCharArray(), false);
      }
  
      /**
       * Converts a byte array to hex string.
       *
       * @param bytes List of bytes for ssid.
       * @throws IllegalArgumentException for null bytes.
       */
      public static String hexStringFromByteArray(byte[] bytes) {
          if (bytes == null) {
              throw new IllegalArgumentException("null hex bytes");
          }
          return new String(HexEncoding.encode(bytes)).toLowerCase();
      }
  
      /**
       * Converts an 8 byte array to a WPS device type string
       * { 0, 1, 2, -1, 4, 5, 6, 7 } --> "1-02FF0405-1543";
       */
      public static String wpsDevTypeStringFromByteArray(byte[] devType) {
          byte[] a = devType;
          int x = ((a[0] & 0xFF) << 8) | (a[1] & 0xFF);
          String y = new String(HexEncoding.encode(Arrays.copyOfRange(devType, 2, 6)));
          int z = ((a[6] & 0xFF) << 8) | (a[7] & 0xFF);
          return String.format("%d-%s-%d", x, y, z);
      }
  }
  