/*
    *    Copyright 2012-2022 the original author or authors.
    *
    *    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
    *
    *       https://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.mybatis.caches.memcached;
  
  import java.security.MessageDigest;
  import java.security.NoSuchAlgorithmException;
  
  /**
   * Got from https://github.com/raykrueger/hibernate-memcached
   *
   * @author Ray Krueger
   */
  public final class StringUtils {
  
    private static final char[] DIGITS = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e',
        'f' };
  
    private StringUtils() {
      // Prevent Instantiation
    }
  
    public static String sha1Hex(String data) {
      if (data == null) {
        throw new IllegalArgumentException("data must not be null");
      }
  
      byte[] bytes = digest("SHA1", data);
  
      return toHexString(bytes);
    }
  
    private static String toHexString(byte[] bytes) {
      int l = bytes.length;
  
      char[] out = new char[l << 1];
  
      for (int i = 0, j = 0; i < l; i++) {
        out[j++] = DIGITS[(0xF0 & bytes[i]) >>> 4];
        out[j++] = DIGITS[0x0F & bytes[i]];
      }
  
      return new String(out);
    }
  
    private static byte[] digest(String algorithm, String data) {
      MessageDigest digest;
      try {
        digest = MessageDigest.getInstance(algorithm);
      } catch (NoSuchAlgorithmException e) {
        throw new RuntimeException(e);
      }
  
      return digest.digest(data.getBytes());
    }
  
  }