;------------------------------------------------------------------------------
; NAME: CLEAN
;     
; PURPOSE: To remove all unprintable characters from the given string
; 
; CALLING SEQUENCE: Result = CLEAN (text, [/SPACE])
; 
; INPUTS:
;    Text: Scalar string of characters to be cleaned
; OUTPUTS:
;    Result: Scalar string of characters removed of all unprintable characters
;
; OPTIONAL INPUTS:
;    SPACE: removes all unprintable characters including all space chars.
;
; EXAMPLE:
;    To remove all unprintable chars except space
;       IDL> word = CLEAN ('the [tab]file is [lf][cr]')
;       IDL> print, word
;            the file is
;    To remove all unprintable chars including space
;       IDL> word = CLEAN ('the [tab]file is [lf][cr]',/SPACE)
;       IDL> print, word
;            thefileis
;
; PROCEDURES USED: none
;
; MODIFICATION HISTORY:
;    Written by:     P. Khetarpal [Jan 15, 2003]
;    Last modified:  Unknown      [< Jan 22, 2013]
;    
;    For a complete list of modifications, see changelog.txt file.
;
;------------------------------------------------------------------------------

function clean, text, SPACE = space
    ; error protection:
    on_error, 2

    ; check for SPACE keyword specification:
    space = keyword_set(space)

    ; process the text only if string is not NULL:
    status = size(text, /type)
    if (status ne 7) then text = string(text)
    if (strlen(text) ne 0) then begin
        btext = byte(text)

        ; find the wanted chars ommitting or including the space char:
        pos = (space) ? where (btext gt 32B and btext lt 127B) : $
                        where (btext ge 32B and btext lt 127B)

        ; assign processed value of text:
        text = (pos[0] ne -1) ? string(btext[pos]) : ""
    endif
    return, text   
end