content: /*
   *  Licensed to the Apache Software Foundation (ASF) under one or more
   *  contributor license agreements.  See the NOTICE file distributed with
   *  this work for additional information regarding copyright ownership.
   *  The ASF licenses this file to You 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.
   */
  
  /**
  * @author Vladimir N. Molotkov, Stepan M. Mishura
  * @version $Revision$
  */
  
  package android.framework.org.apache.harmony.security_custom.asn1;
  
  import java.io.IOException;
  
  /**
   * This class represents ASN.1 Bitstring type.
   *
   * @see <a href="http://asn1.elibel.tm.fr/en/standards/index.htm">ASN.1</a>
   */
  public class ASN1BitString extends ASN1StringType {
  
      // default implementation
      private static final ASN1BitString ASN1 = new ASN1BitString();
  
      /**
       * Constructs ASN.1 Bitstring type
       *
       * The constructor is provided for inheritance purposes
       * when there is a need to create a custom ASN.1 Bitstring type.
       * To get a default implementation it is recommended to use
       * getInstance() method.
       */
      public ASN1BitString() {
          super(TAG_BITSTRING);
      }
  
      /**
       * Returns ASN.1 Bitstring type default implementation
       *
       * The default implementation works with encoding
       * that is represented as BitString object.
       *
       * @return ASN.1 Bitstring type default implementation
       * @see android.framework.org.apache.harmony.security_custom.asn1.BitString
       */
      public static ASN1BitString getInstance() {
          return ASN1;
      }
  
      @Override public Object decode(BerInputStream in) throws IOException {
          in.readBitString();
  
          if (in.isVerify) {
              return null;
          }
          return getDecodedObject(in);
      }
  
      /**
       * Extracts BitString object from BER input stream.
       *
       * @param in - BER input stream
       * @return BitString object
       */
      @Override public Object getDecodedObject(BerInputStream in) throws IOException {
          byte[] bytes = new byte[in.length - 1];
          System.arraycopy(in.buffer, in.contentOffset + 1, bytes, 0,
                  in.length - 1);
          return new BitString(bytes, in.buffer[in.contentOffset]);
      }
  
      @Override public void encodeContent(BerOutputStream out) {
          out.encodeBitString();
      }
  
      @Override public void setEncodingContent(BerOutputStream out) {
          out.length = ((BitString) out.content).bytes.length + 1;
      }
  
      /**
       * Default implementation for ASN.1 Named Bitstring type
       *
       * The default implementation works with encoding
       * that is mapped to array of boolean.
       */
      public static class ASN1NamedBitList extends ASN1BitString {
          private static final byte[] SET_MASK = { (byte) 128, 64, 32, 16, 8, 4, 2, 1};
          private static final BitString emptyString = new BitString(new byte[]{}, 0);
          private static final int INDEFINITE_SIZE = -1;
  
          private final int minBits;
          private final int maxBits;
  
          public ASN1NamedBitList(int minBits) {
              this.minBits = minBits;
              this.maxBits = INDEFINITE_SIZE;
          }
  
          @Override public Object getDecodedObject(BerInputStream in) throws IOException {
              boolean[] value;
  
              int unusedBits = in.buffer[in.contentOffset];
              int bitsNumber = (in.length - 1) * 8 - unusedBits;
  
              if (maxBits == INDEFINITE_SIZE) {
                  if (minBits == INDEFINITE_SIZE) {
                      value = new boolean[bitsNumber];
                  } else {
                      if (bitsNumber > minBits) {
                          value = new boolean[bitsNumber];
                      } else {
                          value = new boolean[minBits];
                      }
                  }
              } else {
                  if (bitsNumber > maxBits) {
                      throw new ASN1Exception("ASN.1 Named Bitstring: size constraints");
                  }
                  value = new boolean[maxBits];
              }
  
              if (bitsNumber == 0) {
                  // empty bit string
                  return value;
              }
  
              int i = 1;
              int j = 0;
              byte octet = in.buffer[in.contentOffset + i];
              for (int size = in.length - 1; i < size; i++) {
                  for (int k = 0; k < 8; k++, j++) {
                      value[j] = (SET_MASK[k] & octet) != 0;
                  }
                  i++;
                  octet = in.buffer[in.contentOffset + i];
              }
  
              // final octet
              for (int k = 0; k < (8 - unusedBits); k++, j++) {
                  value[j] = (SET_MASK[k] & octet) != 0;
              }
  
              return value;
          }
  
          @Override public void setEncodingContent(BerOutputStream out) {
              boolean[] toEncode = (boolean[]) out.content;
  
              int index = toEncode.length - 1;
              while (index > -1 && !toEncode[index]) {
                  index--;
              }
  
              if (index == -1) {
                  out.content = emptyString;
                  out.length = 1;
              } else {
                  int unusedBits = 7 - index % 8;
                  byte[] bytes = new byte[index / 8 + 1];
  
                  int j = 0;
                  index = bytes.length - 1;
                  for (int i = 0; i < index; i++) {
                      for (int k = 0; k < 8; k++, j++) {
                          if (toEncode[j]) {
                              bytes[i] = (byte) (bytes[i] | SET_MASK[k]);
                          }
                      }
                  }
  
                  //final octet
                  for (int k = 0; k < (8 - unusedBits); k++, j++) {
                      if (toEncode[j]) {
                          bytes[index] = (byte) (bytes[index] | SET_MASK[k]);
                      }
                  }
  
                  out.content = new BitString(bytes, unusedBits);
                  out.length = bytes.length + 1;
              }
          }
      }
  }
  