| /* |
| * Copyright (C) 2020 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.integrity.parser; |
| |
| import static com.android.server.integrity.model.ComponentBitSize.IS_HASHED_BITS; |
| import static com.android.server.integrity.model.ComponentBitSize.VALUE_SIZE_BITS; |
| |
| import android.content.integrity.IntegrityUtils; |
| |
| import com.android.server.integrity.model.BitInputStream; |
| |
| import java.io.IOException; |
| import java.nio.ByteBuffer; |
| |
| /** |
| * Helper methods for reading standard data structures from {@link BitInputStream}. |
| */ |
| public class BinaryFileOperations { |
| |
| /** |
| * Read an string value with the given size and hash status from a {@code BitInputStream}. |
| * |
| * If the value is hashed, get the hex-encoding of the value. Serialized values are in raw form. |
| * All hashed values are hex-encoded. |
| */ |
| public static String getStringValue(BitInputStream bitInputStream) throws IOException { |
| boolean isHashedValue = bitInputStream.getNext(IS_HASHED_BITS) == 1; |
| int valueSize = bitInputStream.getNext(VALUE_SIZE_BITS); |
| return getStringValue(bitInputStream, valueSize, isHashedValue); |
| } |
| |
| /** |
| * Read an string value with the given size and hash status from a {@code BitInputStream}. |
| * |
| * If the value is hashed, get the hex-encoding of the value. Serialized values are in raw form. |
| * All hashed values are hex-encoded. |
| */ |
| public static String getStringValue( |
| BitInputStream bitInputStream, int valueSize, boolean isHashedValue) |
| throws IOException { |
| if (!isHashedValue) { |
| StringBuilder value = new StringBuilder(); |
| while (valueSize-- > 0) { |
| value.append((char) bitInputStream.getNext(/* numOfBits= */ 8)); |
| } |
| return value.toString(); |
| } |
| ByteBuffer byteBuffer = ByteBuffer.allocate(valueSize); |
| while (valueSize-- > 0) { |
| byteBuffer.put((byte) (bitInputStream.getNext(/* numOfBits= */ 8) & 0xFF)); |
| } |
| return IntegrityUtils.getHexDigest(byteBuffer.array()); |
| } |
| |
| /** Read an integer value from a {@code BitInputStream}. */ |
| public static int getIntValue(BitInputStream bitInputStream) throws IOException { |
| return bitInputStream.getNext(/* numOfBits= */ 32); |
| } |
| |
| /** Read an boolean value from a {@code BitInputStream}. */ |
| public static boolean getBooleanValue(BitInputStream bitInputStream) throws IOException { |
| return bitInputStream.getNext(/* numOfBits= */ 1) == 1; |
| } |
| } |