excel vba check if specific bits set in int32 code example

Example 1: excel vba check if specific bits set in int32

'Fast VBA function to test if specific bits are set 
'within a 32-bit Long integer. If ALL specified bits are set then 
'this function returns True. If ANY of the specified bits are
'not set then this function returns False.

'Bits are numbered from 0 to 31, so the first (least significant) bit
'is bit 0.

'Note: bits can be specified in any order.
'Note: any number of bits can be specified in one call.


Function LongBitsAreSet(theLong&, ParamArray bits()) As Boolean
    Static i&, b&()
    If UBound(bits) = -1 Then Exit Function
    If (Not Not b) = 0 Then
        ReDim b(0 To 30)
        For i = 0 To 30
            b(i) = 2 ^ i
        Next
    End If
    For i = 0 To UBound(bits)
        If bits(i) < 0 Then Exit Function
        If bits(i) > 30 Then Exit Function
        If (theLong And b(Int(bits(i)))) = 0 Then Exit Function
    Next
    LongBitsAreSet = True
End Function


'---------------------------------------------------------------------------------------------------------------------
MsgBox LongBitsAreSet(255, 7)                    '<--displays: True          255 = 00000000 00000000 00000000 11111111
MsgBox LongBitsAreSet(230, 0)                    '<--displays: False         230 = 00000000 00000000 00000000 11100110
MsgBox LongBitsAreSet(85, 0, 2, 6, 4)            '<--displays: True           85 = 00000000 00000000 00000000 01010101
MsgBox LongBitsAreSet(85, 0, 2, 5, 4)            '<--displays: False          85 = 00000000 00000000 00000000 01010101
MsgBox LongBitsAreSet(485, 2, 7, 5)              '<--displays: True          485 = 00000000 00000000 00000001 11100101
MsgBox LongBitsAreSet(24585, 14, 13, 3)          '<--displays: True        24585 = 00000000 00000000 01100000 00001001
MsgBox LongBitsAreSet(&H7D12EACB, 24, 26, 30, 7) '<--displays: True   2098391755 = 01111101 00010010 11101010 11001011 
'
'
'

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