excelvba check integer bit code example

Example 1: excel vba long to bits

Function LongToBits$(ByVal n&)
    Dim i&
    LongToBits = "00000000000000000000000000000000"
    If n And &H80000000 Then
        Mid$(LongToBits, 1, 1) = "1"
        n = n And Not &H80000000
    End If
    For i = 32 To 2 Step -1
        If n And 1 Then Mid$(LongToBits, i, 1) = "1"
        n = n \ 2
    Next
End Function

'------------------------------------------------------------------------------

MsgBox ByteToBits(0)			'<--displays: 00000000000000000000000000000000
MsgBox LongToBits(293781237)	'<--displays: 00010001100000101011111011110101
MsgBox ByteToBits(-1)			'<--displays: 11111111111111111111111111111111

Example 2: excel vba check if bit is set in integer

'Extremely fast VBA function to test if a specified bit is set 
'within a 16-bit Integer.

'Bits are numbered from 0 to 15, so the first (least significant) bit
'is bit 0.

'Note: we do not inspect bit 15, the sign bit.


Function IntegerBitIsSet(theInteger%, bit As Byte) As Boolean
    Static i&, b%()
    If (Not Not b) = 0 Then
        ReDim b(0 To 14)
        For i = 0 To 14
            b(i) = 2 ^ i
        Next
    End If
    If bit < 15 Then IntegerBitIsSet = theInteger And b(bit)
End Function

'------------------------------------------------------------------
MsgBox IntegerBitIsSet(255, 7)      '<--displays: True
MsgBox IntegerBitIsSet(230, 0)      '<--displays: False
MsgBox IntegerBitIsSet(16384, 14)   '<--displays: True
MsgBox IntegerBitIsSet(-16383, 0)   '<--displays: True

Example 3: excel vba set bit in byte

'Extremely fast VBA function to test if a specified bit is set 
'within a Byte.

'Bits are numbered from 0 to 7, so the first (least significant) bit
'is bit 0.

Function ByteBitIsSet(theByte As Byte, bit As Byte) As Boolean
    Static i&, b() As Byte
    If (Not Not b) = 0 Then
        ReDim b(0 To 7)
        For i = 0 To 7
            b(i) = 2 ^ i
        Next
    End If
    If bit < 8 Then ByteBitIsSet = theByte And b(bit)
End Function

'------------------------------------------------------------------
MsgBox ByteBitIsSet(255, 7)      '<--displays: True
MsgBox ByteBitIsSet(230, 0)      '<--displays: False