MD5.java

// Copyright (c) 2011, Chute Corporation. All rights reserved.
//
//  Redistribution and use in source and binary forms, with or without modification,
//  are permitted provided that the following conditions are met:
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//       list of conditions and the following disclaimer.
//     * Redistributions in binary form must reproduce the above copyright notice,
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package com.chute.sdk.v2.utils;

import java.io.FileInputStream;
import java.io.InputStream;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;

import android.util.Log;

public class MD5 {

  public static final String TAG = MD5.class.getSimpleName();

  private static byte[] createChecksum(String filename) throws Exception {
    InputStream fis = new FileInputStream(filename);

    byte[] buffer = new byte[1024];
    MessageDigest complete = MessageDigest.getInstance("MD5");
    int numRead;
    do {
      numRead = fis.read(buffer);
      if (numRead > 0) {
        complete.update(buffer, 0, numRead);
      }
    } while (numRead != -1);
    fis.close();
    return complete.digest();
  }

  // See this How-to for a faster way to convert
  // a byte array to a HEX string
  public static String getMD5Checksum(String filename) throws Exception {
    byte[] b = createChecksum(filename);
    String result = "";
    for (int i = 0; i < b.length; i++) {
      result += Integer.toString((b[i] & 0xff) + 0x100, 16).substring(1);
    }
    return result;
  }

  public static String getStringMD5(String s) {
    try {
      // Create MD5 Hash
      MessageDigest digest = MessageDigest
          .getInstance("MD5");
      digest.update(s.getBytes());
      byte messageDigest[] = digest.digest();

      // Create Hex String
      StringBuffer hexString = new StringBuffer();
      for (int i = 0; i < messageDigest.length; i++) {
        String h = Integer.toHexString(0xFF & messageDigest[i]);
        while (h.length() < 2) {
          h = "0" + h;
        }
        hexString.append(h);
      }
      return hexString.toString();

    } catch (NoSuchAlgorithmException e) {
      Log.w(TAG, "", e);
    }
    return "";
  }
}