CBitArray – a class for dealing with large arrays of Boolean

CBitArray – a class for dealing with large arrays of Boolean

' ------------------------------------------------------------------------'  The CBITARRAY class''  simiulates an array of Boolean values'  saves memory by packing one element in one bit'' IMPORTANT: you make make ITEM the default member for this class'            do this from inside the Tools | Procedure Attributes dialog box'' Usage:'    Dim bitArr As New CBitArray'    bitArr.Init(10000)         ' 10,000 boolean elements'    ' assign a value'    bitArr(10) = True'    ' read it back'    Print bitArr(10)'' ------------------------------------------------------------------------Option ExplicitDim mask(0 To 7) As IntegerDim values() As BytePublic Sub Init(ByVal numEls As Long)    ' redimension the internal array    ' MUST BE THE FIRST METHOD CALLED FOR THIS CLASS    ReDim values(numEls  8) As ByteEnd SubPrivate Sub Class_Initialize()    ' initialize the mask() array    Dim i As Integer    mask(0) = 1    For i = 1 To 7        mask(i) = mask(i - 1) * 2    NextEnd Sub' for smoother syntax, you should make ITEM the default member for this classProperty Get Item(ByVal index As Long) As Boolean    ' retrieve an array item    Item = values(index  8) And mask(index And 7)End PropertyProperty Let Item(ByVal index As Long, ByVal new_Item As Boolean)    Dim ndx As Long, m As Byte    ' cache the mask into a local variable    m = mask(index And 7)    ndx = index  8    ' set or reset only the relevant bit    values(ndx) = (values(ndx) And Not m) Or (new_Item And m)End Property


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