content: /*
   * Copyright (C) 2010 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 android.nfc.tech;
  
  import android.nfc.ErrorCodes;
  import android.nfc.Tag;
  import android.nfc.TagLostException;
  import android.os.Bundle;
  import android.os.RemoteException;
  import android.util.Log;
  
  import java.io.IOException;
  
  //TOOD: Ultralight C 3-DES authentication, one-way counter
  
  /**
   * Provides access to MIFARE Ultralight properties and I/O operations on a {@link Tag}.
   *
   * <p>Acquire a {@link MifareUltralight} object using {@link #get}.
   *
   * <p>MIFARE Ultralight compatible tags have 4 byte pages {@link #PAGE_SIZE}.
   * The primary operations on an Ultralight tag are {@link #readPages} and
   * {@link #writePage}.
   *
   * <p>The original MIFARE Ultralight consists of a 64 byte EEPROM. The first
   * 4 pages are for the OTP area, manufacturer data, and locking bits. They are
   * readable and some bits are writable. The final 12 pages are the user
   * read/write area. For more information see the NXP data sheet MF0ICU1.
   *
   * <p>The MIFARE Ultralight C consists of a 192 byte EEPROM. The first 4 pages
   * are for OTP, manufacturer data, and locking bits. The next 36 pages are the
   * user read/write area. The next 4 pages are additional locking bits, counters
   * and authentication configuration and are readable. The final 4 pages are for
   * the authentication key and are not readable. For more information see the
   * NXP data sheet MF0ICU2.
   *
   * <p>Implementation of this class on a Android NFC device is optional.
   * If it is not implemented, then
   * {@link MifareUltralight} will never be enumerated in {@link Tag#getTechList}.
   * If it is enumerated, then all {@link MifareUltralight} I/O operations will be supported.
   * In either case, {@link NfcA} will also be enumerated on the tag,
   * because all MIFARE Ultralight tags are also {@link NfcA} tags.
   *
   * <p class="note"><strong>Note:</strong> Methods that perform I/O operations
   * require the {@link android.Manifest.permission#NFC} permission.
   */
  public final class MifareUltralight extends BasicTagTechnology {
      private static final String TAG = "NFC";
  
      /** A MIFARE Ultralight compatible tag of unknown type */
      public static final int TYPE_UNKNOWN = -1;
      /** A MIFARE Ultralight tag */
      public static final int TYPE_ULTRALIGHT = 1;
      /** A MIFARE Ultralight C tag */
      public static final int TYPE_ULTRALIGHT_C = 2;
  
      /** Size of a MIFARE Ultralight page in bytes */
      public static final int PAGE_SIZE = 4;
  
      private static final int NXP_MANUFACTURER_ID = 0x04;
      private static final int MAX_PAGE_COUNT = 256;
  
      /** @hide */
      public static final String EXTRA_IS_UL_C = "isulc";
  
      private int mType;
  
      /**
       * Get an instance of {@link MifareUltralight} for the given tag.
       * <p>Returns null if {@link MifareUltralight} was not enumerated in
       * {@link Tag#getTechList} - this indicates the tag is not MIFARE
       * Ultralight compatible, or that this Android
       * device does not implement MIFARE Ultralight.
       * <p>Does not cause any RF activity and does not block.
       *
       * @param tag an MIFARE Ultralight compatible tag
       * @return MIFARE Ultralight object
       */
      public static MifareUltralight get(Tag tag) {
          if (!tag.hasTech(TagTechnology.MIFARE_ULTRALIGHT)) return null;
          try {
              return new MifareUltralight(tag);
          } catch (RemoteException e) {
              return null;
          }
      }
  
      /** @hide */
      public MifareUltralight(Tag tag) throws RemoteException {
          super(tag, TagTechnology.MIFARE_ULTRALIGHT);
  
          // Check if this could actually be a MIFARE
          NfcA a = NfcA.get(tag);
  
          mType = TYPE_UNKNOWN;
  
          if (a.getSak() == 0x00 && tag.getId()[0] == NXP_MANUFACTURER_ID) {
              Bundle extras = tag.getTechExtras(TagTechnology.MIFARE_ULTRALIGHT);
              if (extras.getBoolean(EXTRA_IS_UL_C)) {
                  mType = TYPE_ULTRALIGHT_C;
              } else {
                  mType = TYPE_ULTRALIGHT;
              }
          }
      }
  
      /**
       * Return the MIFARE Ultralight type of the tag.
       * <p>One of {@link #TYPE_ULTRALIGHT} or {@link #TYPE_ULTRALIGHT_C} or
       * {@link #TYPE_UNKNOWN}.
       * <p>Depending on how the tag has been formatted, it can be impossible
       * to accurately classify between original MIFARE Ultralight and
       * Ultralight C. So treat this method as a hint.
       * <p>Does not cause any RF activity and does not block.
       *
       * @return the type
       */
      public int getType() {
          return mType;
      }
  
      /**
       * Read 4 pages (16 bytes).
       *
       * <p>The MIFARE Ultralight protocol always reads 4 pages at a time, to
       * reduce the number of commands required to read an entire tag.
       * <p>If a read spans past the last readable block, then the tag will
       * return pages that have been wrapped back to the first blocks. MIFARE
       * Ultralight tags have readable blocks 0x00 through 0x0F. So a read to
       * block offset 0x0E would return blocks 0x0E, 0x0F, 0x00, 0x01. MIFARE
       * Ultralight C tags have readable blocks 0x00 through 0x2B. So a read to
       * block 0x2A would return blocks 0x2A, 0x2B, 0x00, 0x01.
       *
       * <p>This is an I/O operation and will block until complete. It must
       * not be called from the main application thread. A blocked call will be canceled with
       * {@link IOException} if {@link #close} is called from another thread.
       *
       * <p class="note">Requires the {@link android.Manifest.permission#NFC} permission.
       *
       * @param pageOffset index of first page to read, starting from 0
       * @return 4 pages (16 bytes)
       * @throws TagLostException if the tag leaves the field
       * @throws IOException if there is an I/O failure, or the operation is canceled
       */
      public byte[] readPages(int pageOffset) throws IOException {
          validatePageIndex(pageOffset);
          checkConnected();
  
          byte[] cmd = { 0x30, (byte) pageOffset};
          return transceive(cmd, false);
      }
  
      /**
       * Write 1 page (4 bytes).
       *
       * <p>The MIFARE Ultralight protocol always writes 1 page at a time, to
       * minimize EEPROM write cycles.
       *
       * <p>This is an I/O operation and will block until complete. It must
       * not be called from the main application thread. A blocked call will be canceled with
       * {@link IOException} if {@link #close} is called from another thread.
       *
       * <p class="note">Requires the {@link android.Manifest.permission#NFC} permission.
       *
       * @param pageOffset index of page to write, starting from 0
       * @param data 4 bytes to write
       * @throws TagLostException if the tag leaves the field
       * @throws IOException if there is an I/O failure, or the operation is canceled
       */
      public void writePage(int pageOffset, byte[] data) throws IOException {
          validatePageIndex(pageOffset);
          checkConnected();
  
          byte[] cmd = new byte[data.length + 2];
          cmd[0] = (byte) 0xA2;
          cmd[1] = (byte) pageOffset;
          System.arraycopy(data, 0, cmd, 2, data.length);
  
          transceive(cmd, false);
      }
  
      /**
       * Send raw NfcA data to a tag and receive the response.
       *
       * <p>This is equivalent to connecting to this tag via {@link NfcA}
       * and calling {@link NfcA#transceive}. Note that all MIFARE Classic
       * tags are based on {@link NfcA} technology.
       *
       * <p>Use {@link #getMaxTransceiveLength} to retrieve the maximum number of bytes
       * that can be sent with {@link #transceive}.
       *
       * <p>This is an I/O operation and will block until complete. It must
       * not be called from the main application thread. A blocked call will be canceled with
       * {@link IOException} if {@link #close} is called from another thread.
       *
       * <p class="note">Requires the {@link android.Manifest.permission#NFC} permission.
       *
       * @see NfcA#transceive
       */
      public byte[] transceive(byte[] data) throws IOException {
          return transceive(data, true);
      }
  
      /**
       * Return the maximum number of bytes that can be sent with {@link #transceive}.
       * @return the maximum number of bytes that can be sent with {@link #transceive}.
       */
      public int getMaxTransceiveLength() {
          return getMaxTransceiveLengthInternal();
      }
  
      /**
       * Set the {@link #transceive} timeout in milliseconds.
       *
       * <p>The timeout only applies to {@link #transceive} on this object,
       * and is reset to a default value when {@link #close} is called.
       *
       * <p>Setting a longer timeout may be useful when performing
       * transactions that require a long processing time on the tag
       * such as key generation.
       *
       * <p class="note">Requires the {@link android.Manifest.permission#NFC} permission.
       *
       * @param timeout timeout value in milliseconds
       */
      public void setTimeout(int timeout) {
          try {
              int err = mTag.getTagService().setTimeout(
                      TagTechnology.MIFARE_ULTRALIGHT, timeout);
              if (err != ErrorCodes.SUCCESS) {
                  throw new IllegalArgumentException("The supplied timeout is not valid");
              }
          } catch (RemoteException e) {
              Log.e(TAG, "NFC service dead", e);
          }
      }
  
      /**
       * Get the current {@link #transceive} timeout in milliseconds.
       *
       * <p class="note">Requires the {@link android.Manifest.permission#NFC} permission.
       *
       * @return timeout value in milliseconds
       */
      public int getTimeout() {
          try {
              return mTag.getTagService().getTimeout(TagTechnology.MIFARE_ULTRALIGHT);
          } catch (RemoteException e) {
              Log.e(TAG, "NFC service dead", e);
              return 0;
          }
      }
  
      private static void validatePageIndex(int pageIndex) {
          // Do not be too strict on upper bounds checking, since some cards
          // may have more addressable memory than they report.
          // Note that issuing a command to an out-of-bounds block is safe - the
          // tag will wrap the read to an addressable area. This validation is a
          // helper to guard against obvious programming mistakes.
          if (pageIndex < 0 || pageIndex >= MAX_PAGE_COUNT) {
              throw new IndexOutOfBoundsException("page out of bounds: " + pageIndex);
          }
      }
  }
  