/*
* 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;
}
}
}