unicodeAllowed: Boolean,
  charset: Charset?,
) {
  var encodedCharBuffer: Buffer? = null // Lazily allocated.
  var codePoint: Int
  var i = pos
  while (i < limit) {
    codePoint = input.codePointAt(i)
    if (alreadyEncoded &&
      (
        codePoint == '\t'.code ||
          codePoint == '\n'.code ||
          codePoint == '\u000c'.code ||
          codePoint == '\r'.code
      )
    ) {

    // Ordinarily we'd use something like i += Character.charCount(string.codePointAt(i)) here. But
    // we can get away with i++ because the whole point of this method is to return false if we find
    // a code point that doesn't fit in a char.
    for (int i = 0; i < string.length(); i++) {
      if (string.codePointAt(i) > 0xffff) {
        return false;
      }
    }
    return true;
  }

        .isEqualTo("\0HELLO \uD800\uDC00 WORLD!\n");
  }

  public void testCodePointAt_indexOutOfBoundsException() {
    assertThrows(
        IndexOutOfBoundsException.class, () -> UnicodeEscaper.codePointAt("Testing...", 4, 2));
  }

  private static String escapeAsString(Escaper e, String s) {
    return e.escape(s);
  }

        // We can't use Character.isSurrogate(c) here and below because of GWT.
        if (MIN_SURROGATE <= c && c <= MAX_SURROGATE) {
          // Check that we have a well-formed surrogate pair.
          if (Character.codePointAt(sequence, i) == c) {
            throw new IllegalArgumentException(unpairedSurrogateMsg(i));
          }
          i++;
        }
      }
    }
    return utf8Length;
  }

  /**

        // We can't use Character.isSurrogate(c) here and below because of GWT.
        if (MIN_SURROGATE <= c && c <= MAX_SURROGATE) {
          // Check that we have a well-formed surrogate pair.
          if (Character.codePointAt(sequence, i) == c) {
            throw new IllegalArgumentException(unpairedSurrogateMsg(i));
          }
          i++;
        }
      }
    }
    return utf8Length;
  }

  /**

        fst.getFirstArc(scratchArc);
        BytesRef matchOutput = null;

        int index = 0;
        while (start + index < src.length) {
            final int codePoint = Character.codePointAt(src, start + index, src.length);
            if (fst.findTargetArc(ignoreCase ? Character.toLowerCase(codePoint) : codePoint, scratchArc, scratchArc, fstReader) == null) {
                return matchOutput;
            }

                try {
                    char low = version.charAt(i + 1);
                    char[] both = {character, low};
                    c = Character.codePointAt(both, 0);
                    i++;
                } catch (IndexOutOfBoundsException ex) {
                    // high surrogate without low surrogate. Not a lot we can do here except treat it as a regular

        if (ComponentUtil.getFessConfig().isQueryHighlightBoundaryPositionDetect()) {
            int pos = escaped.indexOf(escapedHighlightPre);
            while (pos >= 0) {
                final int c = escaped.codePointAt(pos);
                if (Character.isISOControl(c) || highlightTerminalCharSet.contains(c)) {
                    break;
                }
                pos--;
            }

                final int length = spaceStr.length();
                spaceChars = new int[length];
                for (int i = 0; i < length; i++) {
                    spaceChars[i] = spaceStr.codePointAt(i);
                }
            }
            propMap.put(key, spaceChars);
        }
        return spaceChars;
    }

    String getCrawlerDocumentFullstopChars();