'S2FB$ - String to five bite string

'FB2S$ - five bite string back to normal 8 bit string

'allowed characters: abcdefghijklmnopqrstuvwxyz+- '



'can be expanded, but this is not implanted in this version.









txt$ = "text to five byte binary text coder and decoder - first version"

'

t$ = S2FB$(txt$) 'string to five byte code (return binary string code)



Do

    u$ = FB2S$(t$) 'decode binary string t$ to normal text u$

    Print u$

    t$ = S2FB$(txt$) 'make 5 bit coded string from normal text string txt$

    _Limit 20

Loop













Function S2FB$ (S As String) 'returns a binary string encoded in the form of an index in the range 0 to 31, where each number is encoded in five bits according to the internal character table

    Stable$ = "abcdefghijklmnopqrstuvwxyz+- '"

    Dim InputTable(Len(S$)) As _Unsigned _Byte

    i = 0

    For test = 1 To Len(S$)

        ch1$ = Mid$(S$, test, 1)

        Allow = 0

        For compare = 1 To Len(Stable$)

            ch2$ = Mid$(Stable$, compare, 1)

            If ch2$ = ch1$ Then

                Allow = 1

                InputTable(i) = compare 'set indexes to characters in S string

                i = i + 1

            End If

        Next compare

        If Allow = 0 Then Print "Can not create B5$. Unexpected character: "; ch1$: _Display: Sleep 3: End

    Next test



    Dim prd As _Unsigned _Integer64

    Dim me As _MEM

    If Len(S$) > 32 Then me = _MemNew(Len(S$)) Else me = _MemNew(32)

    j = 0

    meStep = 0

    prd = 0



    Do Until j > i

        For t = 1 To 7

            If j > UBound(InputTable) Then Exit For

            prd = prd Or InputTable(j)

            prd = _ShL(prd, 5)

            j = j + 1

        Next t

        _MemPut me, me.OFFSET + meStep, prd

        meStep = meStep + 5

        prd = 0

    Loop

    prd = 0

    Dim V As _Unsigned _Byte

    V = 0



    Code5$ = Space$(meStep)

    _MemGet me, me.OFFSET, Code5$

    S2FB$ = Code5$

    _MemFree me

    Erase InputTable

End Function





Function FB2S$ (code As String) ' Function decode binary string coded in 5 bite and return it as normal 8bit text.

    Stable$ = "abcdefghijklmnopqrstuvwxyz+- '"

    Dim me As _MEM

    MSize = Len(code) * 1.6

    If MSize < 16 Then MSize = 16

    me = _MemNew(MSize)

    _MemFill me, me.OFFSET, me.SIZE, 0 As _UNSIGNED _BYTE 'this is VERY VERY NEED HERE.

    _MemPut me, me.OFFSET, code$



    Dim hodnota As _Unsigned _Integer64

    Dim Vse As _Offset

    Dim Var As _MEM

    Dim prd As _Unsigned _Integer64

    prd = 0

    Var = _Mem(prd)

    If MSize < 5 Then swp$ = Space$(MSize) Else swp$ = Space$(5)

    outb$ = ""



    Vse = 0

    Do Until Vse > me.SIZE - 5

        uu = uu + 1

        _MemGet me, me.OFFSET + Vse, swp$

        _MemPut Var, Var.OFFSET, swp$

        ReDim swp(1 To 8) As _Unsigned _Byte



        For pr = 1 To 8

            hodnota = prd And 31

            swp(9 - pr) = hodnota

            prd = _ShR(prd, 5)

        Next



        For dis = 1 To 8

            outb$ = outb$ + Mid$(Stable$, swp(dis), 1)

        Next



        ReDim swp(1 To 8) As _Unsigned _Byte

        Vse = Vse + 5

        prd = 0

    Loop



    swp$ = ""

    FB2S$ = outb$

    _MemFree me

    _MemFree Var

End Function