StrLoc

From NSIS Wiki

Author: deguix (talk, contrib)


Description

Requires: LogicLib header file.

Version: 2.0.

This function outputs the relative index position from the start or end of a string, where a substring is located. (Case insensitive)

How To Use

Syntax

${StrLoc} "ResultVar" "String" "SubString" "StartPoint"

or

Push "String"
Push "SubString"
Push "StartPoint"
Call StrLoc
Pop "ResultVar"

Parameters

ResultVar
Variable where the relative position index of SubString inside String is returned, according to StartPoint. This value is always smaller or equal than String's length. If SubString is not found, an empty value is returned.
String
String where to search for SubString.
SubString
String to search in String.
StartPoint(>|<)
Start position where the search begins and the counter starts. > = String's start, < = String's end. Default is >.

Example

${StrLoc} $0 "This is just an example" "just" "<"
;$0 = "11"

Function Code

!define StrLoc "!insertmacro StrLoc"
 
!macro StrLoc ResultVar String SubString StartPoint
  Push "${String}"
  Push "${SubString}"
  Push "${StartPoint}"
  Call StrLoc
  Pop "${ResultVar}"
!macroend
 
Function StrLoc
/*After this point:
  ------------------------------------------
   $R0 = StartPoint (input)
   $R1 = SubString (input)
   $R2 = String (input)
   $R3 = SubStringLen (temp)
   $R4 = StrLen (temp)
   $R5 = StartCharPos (temp)
   $R6 = TempStr (temp)*/
 
  ;Get input from user
  Exch $R0
  Exch
  Exch $R1
  Exch 2
  Exch $R2
  Push $R3
  Push $R4
  Push $R5
  Push $R6
 
  ;Get "String" and "SubString" length
  StrLen $R3 $R1
  StrLen $R4 $R2
  ;Start "StartCharPos" counter
  StrCpy $R5 0
 
  ;Loop until "SubString" is found or "String" reaches its end
  ${Do}
    ;Remove everything before and after the searched part ("TempStr")
    StrCpy $R6 $R2 $R3 $R5
 
    ;Compare "TempStr" with "SubString"
    ${If} $R6 == $R1
      ${If} $R0 == `<`
        IntOp $R6 $R3 + $R5
        IntOp $R0 $R4 - $R6
      ${Else}
        StrCpy $R0 $R5
      ${EndIf}
      ${ExitDo}
    ${EndIf}
    ;If not "SubString", this could be "String"'s end
    ${If} $R5 >= $R4
      StrCpy $R0 ``
      ${ExitDo}
    ${EndIf}
    ;If not, continue the loop
    IntOp $R5 $R5 + 1
  ${Loop}
 
  ;Return output to user
  Pop $R6
  Pop $R5
  Pop $R4
  Pop $R3
  Pop $R2
  Exch
  Pop $R1
  Exch $R0
FunctionEnd

Credits

Author: Diego Pedroso (deguix).
Based on StrStr function.

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