Code example for encoding and decoding hexadecimal BBA hand number.

Imports System

'Imports System.Diagnostics.Eventing

'Imports System.Numerics

Module Program

    Public Const C_CLUBS As Integer = 0

    Public Const C_DIAMONDS As Integer = 1

    Public Const C_HEARTS As Integer = 2

    Public Const C_SPADES As Integer = 3

    Public Const C_NT As Integer = 4

    Public Const C_NORTH As Integer = 0

    Public Const C_EAST As Integer = 1

    Public Const C_SOUTH As Integer = 2

    Public Const C_WEST As Integer = 3

    Public Const C_NONE As Long = 0

    Public Const C_NS As Long = 2

    Public Const C_WE As Long = 1

    Public Const C_BOTH As Long = 3

    Public Const C_LONGER As String = "AKQJT98765432"

    Public board(0 To 3, 0 To 3) As Integer

    Public dealers(0 To 15) As Integer

    Public vulnerability(15) As Integer

    Private Structure TYPE_HAND

        Dim suit() As String

    End Structure

    Private Sub set_board()

        '---standard number of a board

        board(C_NORTH, C_NONE) = 1

        board(C_EAST, C_NS) = 2

        board(C_SOUTH, C_WE) = 3

        board(C_WEST, C_BOTH) = 4

        board(C_NORTH, C_NS) = 5

        board(C_EAST, C_WE) = 6

        board(C_SOUTH, C_BOTH) = 7

        board(C_WEST, C_NONE) = 8

        board(C_NORTH, C_WE) = 9

        board(C_EAST, C_BOTH) = 10

        board(C_SOUTH, C_NONE) = 11

        board(C_WEST, C_NS) = 12

        board(C_NORTH, C_BOTH) = 13

        board(C_EAST, C_NONE) = 14

        board(C_SOUTH, C_NS) = 15

        board(C_WEST, C_WE) = 16

    End Sub

    Private Sub set_dealers()

        Dim k As Integer

        For k = 0 To 12 Step 4

            dealers(0 + k) = C_NORTH

            dealers(1 + k) = C_EAST

            dealers(2 + k) = C_SOUTH

            dealers(3 + k) = C_WEST

        Next k

    End Sub

    Private Sub set_vulnerability()

        vulnerability(0) = C_NONE

        vulnerability(1) = C_NS

        vulnerability(2) = C_WE

        vulnerability(3) = C_BOTH

        vulnerability(4) = C_NS

        vulnerability(5) = C_WE

        vulnerability(6) = C_BOTH

        vulnerability(7) = C_NONE

        vulnerability(8) = C_WE

        vulnerability(9) = C_BOTH

        vulnerability(10) = C_NONE

        vulnerability(11) = C_NS

        vulnerability(12) = C_BOTH

        vulnerability(13) = C_NONE

        vulnerability(14) = C_NS

        vulnerability(15) = C_WE

    End Sub

    Sub Main(args As String())

        Dim i As Integer, j As Integer, k As Integer, encryption_byte As Integer, board_extension As Integer

        Dim deal As Integer, dealer As Integer, vulnerable As Integer, number As Integer

        Dim str_card As String, str_Deal As String, str_number As String

        Dim hand() As TYPE_HAND

        Dim lbloki(3) As Integer

        ReDim hand(3)

        For k = 0 To 3

            ReDim hand(k).suit(3)

        Next

        '---example deal

        hand(0).suit(C_CLUBS) = "987"

        hand(0).suit(C_DIAMONDS) = "KQJT7"

        hand(0).suit(C_HEARTS) = "A74"

        hand(0).suit(C_SPADES) = "A6"

        hand(1).suit(C_CLUBS) = "T652"

        hand(1).suit(C_DIAMONDS) = "3"

        hand(1).suit(C_HEARTS) = "QJ82"

        hand(1).suit(C_SPADES) = "J732"

        hand(2).suit(C_CLUBS) = "J3"

        hand(2).suit(C_DIAMONDS) = "A9842"

        hand(2).suit(C_HEARTS) = "K3"

        hand(2).suit(C_SPADES) = "T984"

        hand(3).suit(C_CLUBS) = "AKQ4"

        hand(3).suit(C_DIAMONDS) = "65"

        hand(3).suit(C_HEARTS) = "T965"

        hand(3).suit(C_SPADES) = "KQ5"

        set_board()

        set_dealers()

        set_vulnerability()

        '---coding max number = 256

        deal = 234

        j = (deal - 1) Mod 16

        dealer = dealers(j)

        vulnerable = vulnerability(j)

        Console.WriteLine("coding deal = " & deal)

        board_extension = ((deal - 1) \ 16) Mod 16

        str_Deal = Hex(board_extension) & Hex(dealer * 4 + vulnerable)

        encryption_byte = board(dealer, vulnerable)

            For j = 1 To 13

                number = 0

                str_card = Mid$(C_LONGER, j, 1)

                For i = 0 To 3

                    For k = 0 To 3

                        If InStr(1, hand(k).suit(i), str_card) > 0 Then

                            number = number + k * (4 ^ i)

                        End If

                    Next k

                Next i

                '---additional coding

                number = encryption_byte Xor number

                str_card = Hex(number)

                If Len(str_card) = 1 Then

                    str_card = "0" & str_card

                End If

                str_Deal = str_Deal & str_card

            Next j

         Console.WriteLine("str_deal = " & str_Deal)

        '---decoding

        For k = 0 To 3

                ReDim hand(k).suit(3)

Next

            str_number = Left$(str_Deal, 1)

            board_extension = CLng("&H" & str_number)

            str_number = Mid$(str_Deal, 2, 1)

            number = CLng("&H" & str_number)

            dealer = number \ 4

            vulnerable = number Mod 4

            deal = board_extension * 16 + board(dealer, vulnerable)

            encryption_byte = board(dealer, vulnerable)

        For j = 1 To 13

            str_card = Mid$(C_LONGER, j, 1)

            str_number = Mid$(str_Deal, 2 * j + 1, 2)

            '---0-15

            number = CLng("&H" & str_number)

            number = encryption_byte Xor number

            lbloki(0) = number Mod 4

            lbloki(1) = (number \ 4) Mod 4

            lbloki(2) = (number \ 16) Mod 4

            lbloki(3) = number \ 64

            For i = 0 To 3

                k = lbloki(i)

                hand(k).suit(i) = hand(k).suit(i) & str_card

            Next i

        Next j

        Console.WriteLine("decoding deal = " & deal)

        For k = 0 To 3

                For i = 3 To 0 Step -1

                    Console.Write(hand(k).suit(i))

                    If (i > 0) Then

                        Console.Write(".")

                    End If

                Next

                Console.WriteLine()

            Next

        End Sub

End Module