| /* |
| * Copyright (C) 2021 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.libraries.entitlement.utils; |
| |
| import androidx.annotation.Nullable; |
| |
| import java.nio.ByteBuffer; |
| |
| public class BytesConverter { |
| private static final int INTEGER_SIZE = 4; // 4 bytes |
| |
| // A table mapping from a number to a hex character for fast encoding hex strings. |
| private static final char[] HEX_CHARS = { |
| '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F' |
| }; |
| |
| /** |
| * Converts a byte array into a String of hexadecimal characters. |
| * |
| * @param bytes an array of bytes |
| * @return hex string representation of bytes array |
| */ |
| @Nullable |
| public static String convertBytesToHexString(byte[] bytes) { |
| if (bytes == null) { |
| return null; |
| } |
| |
| StringBuilder ret = new StringBuilder(2 * bytes.length); |
| |
| for (int i = 0; i < bytes.length; i++) { |
| int b; |
| b = 0x0f & (bytes[i] >> 4); |
| ret.append(HEX_CHARS[b]); |
| b = 0x0f & bytes[i]; |
| ret.append(HEX_CHARS[b]); |
| } |
| |
| return ret.toString(); |
| } |
| |
| /** |
| * Converts integer to 4 bytes. |
| */ |
| public static byte[] convertIntegerTo4Bytes(int value) { |
| return ByteBuffer.allocate(INTEGER_SIZE).putInt(value).array(); |
| } |
| } |