int i = 0;

        // This loop optimizes for pure ASCII.
        while (i + 4 <= utf16Length) {
          char c0 = input.charAt(i);
          char c1 = input.charAt(i + 1);
          char c2 = input.charAt(i + 2);
          char c3 = input.charAt(i + 3);
          if (c0 < 0x80 && c1 < 0x80 && c2 < 0x80 && c3 < 0x80) {
            update(4, c0 | (c1 << 8) | (c2 << 16) | (c3 << 24));

        }
      }
      return chars.subSequence(0, l + 1);
    }

    @Override
    public boolean canDecode(CharSequence chars) {
      checkNotNull(chars);
      chars = trimTrailingPadding(chars);
      if (!alphabet.isValidPaddingStartPosition(chars.length())) {
        return false;
      }
      for (int i = 0; i < chars.length(); i++) {
        if (!alphabet.canDecode(chars.charAt(i))) {
          return false;

        final char[] chars = new char[text.length()];
        for (int i = 0; i < chars.length; i++) {
            final char c = text.charAt(i);
            if (c >= 'ａ' && c <= 'ｚ') {
                chars[i] = (char) (c - 'ａ' + 'a');
            } else if (c >= 'Ａ' && c <= 'Ｚ') {
                chars[i] = (char) (c - 'Ａ' + 'A');
            } else if (c >= '１' && c <= '０') {

    Set<Character> positive = Sets.newHashSetWithExpectedSize(chars.length);
    for (char c : chars) {
      positive.add(c);
    }
    for (int c = 0; c <= Character.MAX_VALUE; c++) {
      assertFalse(positive.contains(Character.valueOf((char) c)) ^ m.matches((char) c));
    }
  }

  static char[] randomChars(Random rand, int size) {
    Set<Character> chars = new HashSet<>(size);

  private static final class AnyOf extends CharMatcher {

    private final char[] chars;

    public AnyOf(CharSequence chars) {
      this.chars = chars.toString().toCharArray();
      Arrays.sort(this.chars);
    }

    @Override
    public boolean matches(char c) {
      return Arrays.binarySearch(chars, c) >= 0;
    }

    @Override

    if (chars instanceof String) {
      return toLowerCase((String) chars);
    }
    char[] newChars = new char[chars.length()];
    for (int i = 0; i < newChars.length; i++) {
      newChars[i] = toLowerCase(chars.charAt(i));
    }
    return String.valueOf(newChars);
  }

  /**
   * If the argument is an {@linkplain #isUpperCase(char) uppercase ASCII character}, returns the

   *
   * @return the replacement characters, or {@code null} if no escaping was required
   */
  @Override
  @CheckForNull
  protected final char[] escape(int cp) {
    if (cp < replacementsLength) {
      char[] chars = replacements[cp];
      if (chars != null) {
        return chars;
      }
    }
    if (cp >= safeMin && cp <= safeMax) {
      return null;
    }
    return escapeUnsafe(cp);
  }

        if (isEmpty(name)) {
            return name;
        }
        final char[] chars = name.toCharArray();
        if (chars.length >= 2 && Character.isUpperCase(chars[0]) && Character.isUpperCase(chars[1])) {
            return name;
        }
        chars[0] = Character.toLowerCase(chars[0]);
        return new String(chars);
    }

    /**

    Set<Character> positive = Sets.newHashSetWithExpectedSize(chars.length);
    for (char c : chars) {
      positive.add(c);
    }
    for (int c = 0; c <= Character.MAX_VALUE; c++) {
      assertFalse(positive.contains(Character.valueOf((char) c)) ^ m.matches((char) c));
    }
  }

  static char[] randomChars(Random rand, int size) {
    Set<Character> chars = new HashSet<>(size);

    final String allMatchingChars = allMatchingChars(bitSet);
    final char[] result = new char[STRING_LENGTH];
    // Fill with matching chars.
    for (int i = 0; i < result.length; i++) {
      result[i] = allMatchingChars.charAt(random.nextInt(allMatchingChars.length()));
    }
    // Replace some of chars by non-matching.
    int remaining = (int) ((100 - percentMatching) * result.length / 100.0 + 0.5);