content: package my.project.sakuraproject.util;
  
  import java.io.IOException;
  import java.io.InputStream;
  import java.security.MessageDigest;
  import java.security.NoSuchAlgorithmException;
  public class DigestUtils {
      private static final String MD5_ALGORITHM_NAME = "MD5";
      private static final char[] HEX_CHARS = new char[]{'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f'};
  
      public DigestUtils() {}
  
      public static byte[] md5Digest(byte[] bytes) {
          return digest("MD5", bytes);
      }
  
      public static byte[] md5Digest(InputStream inputStream) throws IOException {
          return digest("MD5", inputStream);
      }
  
      public static String md5DigestAsHex(byte[] bytes) {
          return digestAsHexString("MD5", bytes);
      }
  
      public static String md5DigestAsHex(InputStream inputStream) throws IOException {
          return digestAsHexString("MD5", inputStream);
      }
  
      public static StringBuilder appendMd5DigestAsHex(byte[] bytes, StringBuilder builder) {
          return appendDigestAsHex("MD5", bytes, builder);
      }
  
      public static StringBuilder appendMd5DigestAsHex(InputStream inputStream, StringBuilder builder) throws IOException {
          return appendDigestAsHex("MD5", inputStream, builder);
      }
  
      private static MessageDigest getDigest(String algorithm) {
          try {
              return MessageDigest.getInstance(algorithm);
          } catch (NoSuchAlgorithmException var2) {
              throw new IllegalStateException("Could not find MessageDigest with algorithm \"" + algorithm + "\"", var2);
          }
      }
  
      private static byte[] digest(String algorithm, byte[] bytes) {
          return getDigest(algorithm).digest(bytes);
      }
  
      private static byte[] digest(String algorithm, InputStream inputStream) throws IOException {
          MessageDigest messageDigest = getDigest(algorithm);
          if (inputStream instanceof UpdateMessageDigestInputStream) {
              ((UpdateMessageDigestInputStream)inputStream).updateMessageDigest(messageDigest);
              return messageDigest.digest();
          } else {
              byte[] buffer = new byte[4096];
              boolean var4 = true;
  
              int bytesRead;
              while((bytesRead = inputStream.read(buffer)) != -1) {
                  messageDigest.update(buffer, 0, bytesRead);
              }
  
              return messageDigest.digest();
          }
      }
  
      private static String digestAsHexString(String algorithm, byte[] bytes) {
          char[] hexDigest = digestAsHexChars(algorithm, bytes);
          return new String(hexDigest);
      }
  
      private static String digestAsHexString(String algorithm, InputStream inputStream) throws IOException {
          char[] hexDigest = digestAsHexChars(algorithm, inputStream);
          return new String(hexDigest);
      }
  
      private static StringBuilder appendDigestAsHex(String algorithm, byte[] bytes, StringBuilder builder) {
          char[] hexDigest = digestAsHexChars(algorithm, bytes);
          return builder.append(hexDigest);
      }
  
      private static StringBuilder appendDigestAsHex(String algorithm, InputStream inputStream, StringBuilder builder) throws IOException {
          char[] hexDigest = digestAsHexChars(algorithm, inputStream);
          return builder.append(hexDigest);
      }
  
      private static char[] digestAsHexChars(String algorithm, byte[] bytes) {
          byte[] digest = digest(algorithm, bytes);
          return encodeHex(digest);
      }
  
      private static char[] digestAsHexChars(String algorithm, InputStream inputStream) throws IOException {
          byte[] digest = digest(algorithm, inputStream);
          return encodeHex(digest);
      }
  
      private static char[] encodeHex(byte[] bytes) {
          char[] chars = new char[32];
  
          for(int i = 0; i < chars.length; i += 2) {
              byte b = bytes[i / 2];
              chars[i] = HEX_CHARS[b >>> 4 & 15];
              chars[i + 1] = HEX_CHARS[b & 15];
          }
  
          return chars;
      }
  }
  