Remove Invalid Characters in Unicode

 data:  length type i,
        off TYPE i,
        HEXSTRING(4) TYPE C,
        lv_value(40) type c.

  FIELD-SYMBOLS: <INCHAR>.

  lv_value = 'asdasdasdasd '. " input string

  length = STRLEN( lv_value ).

  REPLACE ALL OCCURRENCES OF cl_abap_char_utilities=>newline IN lv_value WITH ' '.

  REPLACE ALL OCCURRENCES OF cl_abap_char_utilities=>HORIZONTAL_TAB IN lv_value WITH ' '.

  REPLACE ALL OCCURRENCES OF cl_abap_char_utilities=>VERTICAL_TAB IN lv_value WITH ' '.

  REPLACE ALL OCCURRENCES OF cl_abap_char_utilities=>CR_LF IN lv_value WITH ' '.

  do length times.

    off = sy-index - 1.
    ASSIGN lv_value+off(1) to <INCHAR>.
    CALL FUNCTION 'YY_CHAR_HEX_CONV'
      EXPORTING
        INPUT     = <INCHAR>
      IMPORTING
        HEXSTRING = HEXSTRING.

* replace with a blank character if any of the following is met

    IF HEXSTRING = '0009'.                       " Horizontal tab
      lv_value+off(1) = ' '.
    elseif hexstring = '000A'.                   " Line feed, new line
      lv_value+off(1) = ' '.
    elseif hexstring = '0023'.
      lv_value+off(1) = ' '.                     " device control 3
    ENDIF.
  enddo.
  RESULT = lv_value.

" Code for YY_CHAR_HEX_CONV
FIELD-SYMBOLS: <DUMMY>.
ASSIGN INPUT TO <DUMMY> TYPE 'X'.
hexstring = <dummy>.