StrContains.nsh

Var STR_HAYSTACK
Var STR_NEEDLE
Var STR_CONTAINS_VAR_1
Var STR_CONTAINS_VAR_2
Var STR_CONTAINS_VAR_3
Var STR_CONTAINS_VAR_4
Var STR_RETURN_VAR
 
Function StrContains
  Exch $STR_NEEDLE
  Exch 1
  Exch $STR_HAYSTACK
  ; Uncomment to debug
  ;MessageBox MB_OK 'STR_NEEDLE = $STR_NEEDLE STR_HAYSTACK = $STR_HAYSTACK '
    StrCpy $STR_RETURN_VAR ""
    StrCpy $STR_CONTAINS_VAR_1 -1
    StrLen $STR_CONTAINS_VAR_2 $STR_NEEDLE
    StrLen $STR_CONTAINS_VAR_4 $STR_HAYSTACK
    loop:
      IntOp $STR_CONTAINS_VAR_1 $STR_CONTAINS_VAR_1 + 1
      StrCpy $STR_CONTAINS_VAR_3 $STR_HAYSTACK $STR_CONTAINS_VAR_2 $STR_CONTAINS_VAR_1
      StrCmp $STR_CONTAINS_VAR_3 $STR_NEEDLE found
      StrCmp $STR_CONTAINS_VAR_1 $STR_CONTAINS_VAR_4 done
      Goto loop
    found:
      StrCpy $STR_RETURN_VAR $STR_NEEDLE
      Goto done
    done:
   Pop $STR_NEEDLE ;Prevent "invalid opcode" errors and keep the
   Exch $STR_RETURN_VAR  
FunctionEnd
 
!macro _StrContainsConstructor OUT NEEDLE HAYSTACK
  Push `${HAYSTACK}`
  Push `${NEEDLE}`
  Call StrContains
  Pop `${OUT}`
!macroend
 
!define StrContains '!insertmacro "_StrContainsConstructor"'