;-------------------------------------------------------------
;+
; NAME:
;       REPCHR
; PURPOSE:
;       Replace all occurrences of one character with another in a text string.
; CATEGORY:
; CALLING SEQUENCE:
;       new = repchr(old, c1, [c2])
; INPUTS:
;       old = original text string.          in
;       c1 = character to replace.           in
;       c2 = character to replace it with.   in
;            default is space.
; KEYWORD PARAMETERS:
; OUTPUTS:
;       new = edited string.                 out
; COMMON BLOCKS:
; NOTES:
; MODIFICATION HISTORY:
;       R. Sterner.  28 Oct, 1986.
;       Johns Hopkins Applied Physics Lab.
;       RES 1 Sep, 1989 --- converted to SUN.
;
; Copyright (C) 1986, Johns Hopkins University/Applied Physics Laboratory
; This software may be used, copied, or redistributed as long as it is not
; sold and this copyright notice is reproduced on each copy made.  This
; routine is provided as is without any express or implied warranties
; whatsoever.  Other limitations apply as described in the file disclaimer.txt.
;-
;-------------------------------------------------------------

        FUNCTION REPCHR, OLD, C1, C2, help=hlp

        if (n_params(0) lt 2) or keyword_set(help) then begin
          print,' Replace all occurrences of one character with another '+$
            'in a text string.'
          print,' new = repchr(old, c1, [c2])'
          print,'   old = original text string.          in'
          print,'   c1 = character to replace.           in'
          print,'   c2 = character to replace it with.   in'
          print,'        default is space.'
          print,'   new = edited string.                 out'
          return, -1
        endif

        B = BYTE(OLD)                      ; convert string to a byte array.
        CB1 = BYTE(C1)                     ; convert char 1 to byte.
        W = WHERE(B EQ CB1(0))             ; find occurrences of char 1.
        IF W(0) EQ -1 THEN RETURN, OLD     ; if none, return old string.
        IF N_PARAMS(0) LT 3 THEN C2 = ' '  ; default char 2 is space.
        CB2 = BYTE(C2)                     ; convert char 2 to byte.
        B(W) = CB2(0)                      ; replace char 1 by char 2.
        RETURN, STRING(B)                  ; return new string.
        END