Metheny
11th August 2010 23:45 UTC

Luhn validation algorithm
Hello, I needed a modified version of Luhn Algorithm into one installer and I didn't see anything similar on the wiki/forum, so here's the validation algorithm, it might be useful for someone.
The example needs NSISArray and PassDialog to work.
My 2 cents...

Name    "Luhn_Algorithm"
OutFile "Luhn_Algorithm.exe"

## Include headers
!include MUI.nsh
!include NSISArray.nsh

## Pages
Page Custom NumberPageShow NumberPageLeave
!insertmacro MUI_PAGE_COMPONENTS
!insertmacro MUI_PAGE_INSTFILES

## Languages
!insertmacro MUI_LANGUAGE English

Var Checksum
Var Numbers

Function NumberPageShow
 !insertmacro MUI_HEADER_TEXT "Luhn algorithm validation" ""

 PassDialog::Dialog Serial           \
                    /HEADINGTEXT "Enter the number that you want to check." \
                    /CENTER             \
                    /BOXDASH 62  70 4 '' \
                    /BOXDASH 142 70 4 ''  \
                    /BOXDASH 222 70 4 ''   \
                    /BOX     302 70 4 ''

 Pop $R0 
FunctionEnd 

Function NumberPageLeave
        Pop $R0
        Pop $R1
        Pop $R2
        Pop $R3         
                                             
        StrCpy $Numbers $R0$R1$R2$R3         
        Goto checkKey
        
        checkKey:
        ${Array} array 9 3
        ${ArrayFunc} WriteList
        ${ArrayFunc} Read
        ${array->Init}       
        StrCpy $Checksum "0"  
        ${array->WriteList} '"0" "1" "2" "3" "4" "-4" "-3" "-2" "-1" "0"' 
        StrCpy $R6 15   # Numbers length - 1
        ${Do}                                                              
          StrCpy $0 "$R0$R1$R2$R3" 1 $R6                                                                                 
          IntOp $Checksum $Checksum + $0                                   
          Math::script "a = $R6; b = 16; c = 2; r9 = a; r1 = b; r2 = c; z = ((a - b) % c); r4 = #[z == 0, 'Valid', 'Invalid']"
          ${If} $4 == 'Valid'                                              
            ${array->Read} $R7 $0
                IntOp $Checksum $Checksum + $R7                                
          ${EndIf}
          IntOp $R6 $R6 - 1
        ${LoopUntil} $R6 = -1           
        ${array->Delete}
        Math::script "a = $Checksum; b = 10; r0 = a; r1 = b; z = a % b; r2 = #[z == 0, 'Valid', 'Invalid']"
        
        ${If} $2 == 'Valid'
                Goto success
    ${Else}
                Goto returnError
        ${EndIf}
        
        returnError:
        MessageBox MB_OK|MB_ICONEXCLAMATION "Wrong number"
    Abort

        success:
FunctionEnd

Section "dummy"

SectionEnd

I'll try to write Verhoeff now.

See you.