code: private void _comment() throws
        IOException,
        CssException
    {
      if (debug)
      {
        checkState(reader.curChar == '/' && reader.peek() == '*');
      }
      /*
         * badcomment1 \/\*[^*]*\*+([^/*][^*]*\*+)* badcomment2
         * \/\*[^*]*(\*+[^/*][^*]*)* comment \/\*[^*]*\*+([^/*][^*]*\*+)*\/
         *
         *
         * "comments can not nest" just close at first occurrence of comment
         * close and let the grammar level handle reporting
         */
  
      builder.type = Type.COMMENT;
  
      reader.next(); // '*'
  
      while (true)
      {
        Mark mark = reader.mark();
        int ch = reader.next();
        if (ch == -1)
        {
          builder.error(SCANNER_PREMATURE_EOF, reader);
          reader.unread(ch, mark);
          break;
        }
        else if (ch == '*' && reader.peek() == '/')
        {
          reader.next();
          break;
        }
        else
        {
          builder.append(ch);
        }
      }
  
      if (debug && builder.errors.size() < 1)
      {
        checkState('/' == reader.curChar && '*' == reader.prevChar);
      }
  
    }
docs: Builds a comment token, excluding the leading and trailing comment
  tokens.