/*
    * Licensed to the Apache Software Foundation (ASF) under one
    * or more contributor license agreements.  See the NOTICE file
    * distributed with this work for additional information
    * regarding copyright ownership.  The ASF licenses this file
    * to you 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 org.apache.hadoop.chukwa.validationframework.util;
  
  
  import java.io.File;
  import java.io.FileInputStream;
  import java.io.InputStream;
  import java.security.MessageDigest;
  import org.apache.hadoop.fs.FSDataInputStream;
  import org.apache.hadoop.fs.FileSystem;
  import org.apache.hadoop.fs.Path;
  
  public class MD5 {
    public static String checksum(File file) {
      try {
        InputStream fin = new FileInputStream(file);
        java.security.MessageDigest md5er = MessageDigest.getInstance("MD5");
        byte[] buffer = new byte[1024];
        int read;
        do {
          read = fin.read(buffer);
          if (read > 0)
            md5er.update(buffer, 0, read);
        } while (read != -1);
        fin.close();
        byte[] digest = md5er.digest();
        if (digest == null)
          return null;
        String strDigest = "0x";
        for (int i = 0; i < digest.length; i++) {
          strDigest += Integer.toString((digest[i] & 0xff) + 0x100, 16)
              .substring(1).toUpperCase();
        }
        return strDigest;
      } catch (Exception e) {
        return null;
      }
    }
  
    public static String checksum(FileSystem fs, Path file) {
      try {
        FSDataInputStream fin = fs.open(file);
        java.security.MessageDigest md5er = MessageDigest.getInstance("MD5");
        byte[] buffer = new byte[1024];
        int read;
        do {
          read = fin.read(buffer);
          if (read > 0)
            md5er.update(buffer, 0, read);
        } while (read != -1);
        fin.close();
        byte[] digest = md5er.digest();
        if (digest == null)
          return null;
        String strDigest = "0x";
        for (int i = 0; i < digest.length; i++) {
          strDigest += Integer.toString((digest[i] & 0xff) + 0x100, 16)
              .substring(1).toUpperCase();
        }
        return strDigest;
      } catch (Exception e) {
        return null;
      }
    }
  }