Manipulate text file by line

here is two function i wrote both search for whole line of text in a text file if match was found (only the first line which match) either add one line after it or replace it with another I use this to configure some .ini file

;----------------------------------------
;cfini.nsh
;
;Functions for configurating ini files
;
; !include "cfini.nsh"
;-----------------------------------------
 
;-----------------------------------------
; Desc. add one line after the first instance
; of "something\r\n" is found
;-----------------------------------------
;how to use
;Push "line search"                #-- line to be found
;Push "line added"                #-- line to be added
;Push "C:\XXX\XXX.ini"     #-- file to be searched in
;
Function INIAddLine
 
  Exch $0    ;file to replace in
  Exch 
  Exch $1    ;line to be added
  Exch 
  Exch 2
  Exch $2    ;line to be search
  Exch 2
 
  Push $R0   ;save data,then use to open file
  Push $R1   ;save data,then use to temp file
  Push $R2   ;save data,then use to tmpstring
 
  ClearErrors
 
  FileOpen $R0 "$0" a
  FileOpen $R1 temp.ini w
 
    FileRead $R0 $R2
    IfErrors +11
;search for a string
    StrCmp "$2" $R2 +4 0
    StrCmp "$2$\r$\n" "$R2" +6 0
;not found yet
    Filewrite $R1 $R2
    GOTO -5
;add a line
    Filewrite $R1 $R2
    Filewrite $R1 "$\r$\n$1"
    GOTO -8
    Filewrite $R1 $R2
    Filewrite $R1 "$1$\r$\n"
    GOTO -11
;done
    FileClose $R0
    FileClose $R1
  ;use the temp to replace the original file
  Delete "$0"
  CopyFiles temp.ini "$0"
  Delete "$OUTDIR\temp.ini"
 
  POP $R2  ;restore
  POP $R1  ;restore
  POP $R0  ;restore
  POP $0   
  POP $1
  POP $2
 
FunctionEnd

;-----------------------------------------
; Desc. replace one line after the first instance
; of "something\r\n" is found
;-----------------------------------------
;how to use
;Push "line search"                #-- line to be found
;Push "line replacing"                #-- line to be added
;Push "C:\XXX\XXX.ini"     #-- file to be searched in
;
Function INIChgLine
 
  Exch $0    ;file to replace in
  Exch 
  Exch $1    ;line to be changed
  Exch 
  Exch 2
  Exch $2    ;line to be search
  Exch 2
 
  Push $R0   ;for open file
  Push $R1   ;for temp file
  Push $R2
 
  ClearErrors
 
  FileOpen $R0 "$0" a
  FileOpen $R1 temp.ini w
 
    FileRead $R0 $R2
    IfErrors +9
;search for a string
    StrCmp "$2" $R2 +4 0
    StrCmp "$2$\r$\n" $R2 +5 0
;not found yet
    Filewrite $R1 $R2
    GOTO -5
;change a line
    Filewrite $R1 "$1"
    GOTO -7
    Filewrite $R1 "$1$\r$\n"
    GOTO -9
;done
    FileClose $R0
    FileClose $R1
  ;use the temp to replace the original file
  Delete "$0"
  CopyFiles temp.ini "$0"
  Delete "$OUTDIR\temp.ini"
 
  POP $R2
  POP $R1
  pop $R0
  POP $0   
  POP $1
  POP $2
 
FunctionEnd