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.apksig.internal.asn1.ber;
  
  import java.nio.ByteBuffer;
  
  /**
   * ASN.1 Basic Encoding Rules (BER) data value -- see {@code X.690}.
   */
  public class BerDataValue {
      private final ByteBuffer mEncoded;
      private final ByteBuffer mEncodedContents;
      private final int mTagClass;
      private final boolean mConstructed;
      private final int mTagNumber;
  
      BerDataValue(
              ByteBuffer encoded,
              ByteBuffer encodedContents,
              int tagClass,
              boolean constructed,
              int tagNumber) {
          mEncoded = encoded;
          mEncodedContents = encodedContents;
          mTagClass = tagClass;
          mConstructed = constructed;
          mTagNumber = tagNumber;
      }
  
      /**
       * Returns the tag class of this data value. See {@link BerEncoding} {@code TAG_CLASS}
       * constants.
       */
      public int getTagClass() {
          return mTagClass;
      }
  
      /**
       * Returns {@code true} if the content octets of this data value are the complete BER encoding
       * of one or more data values, {@code false} if the content octets of this data value directly
       * represent the value.
       */
      public boolean isConstructed() {
          return mConstructed;
      }
  
      /**
       * Returns the tag number of this data value. See {@link BerEncoding} {@code TAG_NUMBER}
       * constants.
       */
      public int getTagNumber() {
          return mTagNumber;
      }
  
      /**
       * Returns the encoded form of this data value.
       */
      public ByteBuffer getEncoded() {
          return mEncoded.slice();
      }
  
      /**
       * Returns the encoded contents of this data value.
       */
      public ByteBuffer getEncodedContents() {
          return mEncodedContents.slice();
      }
  
      /**
       * Returns a new reader of the contents of this data value.
       */
      public BerDataValueReader contentsReader() {
          return new ByteBufferBerDataValueReader(getEncodedContents());
      }
  
      /**
       * Returns a new reader which returns just this data value. This may be useful for re-reading
       * this value in different contexts.
       */
      public BerDataValueReader dataValueReader() {
          return new ParsedValueReader(this);
      }
  
      private static final class ParsedValueReader implements BerDataValueReader {
          private final BerDataValue mValue;
          private boolean mValueOutput;
  
          public ParsedValueReader(BerDataValue value) {
              mValue = value;
          }
  
          @Override
          public BerDataValue readDataValue() throws BerDataValueFormatException {
              if (mValueOutput) {
                  return null;
              }
              mValueOutput = true;
              return mValue;
          }
      }
  }
  