| /* |
| * 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.server.net.watchlist; |
| |
| import java.io.File; |
| import java.io.FileInputStream; |
| import java.io.IOException; |
| import java.io.InputStream; |
| import java.security.MessageDigest; |
| import java.security.NoSuchAlgorithmException; |
| |
| /** |
| * Utils for calculating digests. |
| */ |
| public class DigestUtils { |
| |
| private static final int FILE_READ_BUFFER_SIZE = 16 * 1024; |
| |
| private DigestUtils() {} |
| |
| /** @return SHA256 hash of the provided file */ |
| public static byte[] getSha256Hash(File apkFile) throws IOException, NoSuchAlgorithmException { |
| try (InputStream stream = new FileInputStream(apkFile)) { |
| return getSha256Hash(stream); |
| } |
| } |
| |
| /** @return SHA256 hash of data read from the provided input stream */ |
| public static byte[] getSha256Hash(InputStream stream) |
| throws IOException, NoSuchAlgorithmException { |
| MessageDigest digester = MessageDigest.getInstance("SHA256"); |
| |
| int bytesRead; |
| byte[] buf = new byte[FILE_READ_BUFFER_SIZE]; |
| while ((bytesRead = stream.read(buf)) >= 0) { |
| digester.update(buf, 0, bytesRead); |
| } |
| return digester.digest(); |
| } |
| } |