CODEWITHSUNDEEP
powershellbit-manipulationpowershell-2.0bit-shift
mcu
mcu

Reputation: 3512

Bit Shifting in PowerShell 2.0

Shift left (-shl) and shift right (-shr) operators are only available with PowerShell 3.0 and higher.

How can I shift in PowerShell 2.0?

This is what I have so far. Is there a better way?

>>>$x = 1
>>>$shift = 3
>>>$x * [math]::pow(2, $shift)
8
>>>$x = 32
>>>$shift = -3
>>>$x * [math]::pow(2, $shift)
4

Upvotes: 2

Views: 5094

Answers (2)

karliwson
karliwson

Reputation: 3485

I stumbled upon the same problem, and I'd like to include some useful information:

PoSh2.0-BitShifting creates a $Global:Bitwise object that provides most of the bitwise operations.

Example of use (from its own readme):

PS C:\> Enable-BitShift
PS C:\> $Bitwise

IsPublic IsSerial Name                                     BaseType
-------- -------- ----                                     --------
True     False    PoShBitwiseBuilder                       System.Object


PS C:\> $Bitwise::Lsh(32,2)
128
PS C:\> $Bitwise::Rsh(128,2)
32

Upvotes: 1

Mathias R. Jessen
Mathias R. Jessen

Reputation: 174900

Unfortunately you can't implement new operators in PowerShell (afaik), but you could wrap the operation inside a function:

function bitshift {
    param(
        [Parameter(Mandatory,Position=0)]
        [int]$x,

        [Parameter(ParameterSetName='Left')]
        [ValidateRange(0,[int]::MaxValue)]
        [int]$Left,

        [Parameter(ParameterSetName='Right')]
        [ValidateRange(0,[int]::MaxValue)]
        [int]$Right
    ) 

    $shift = if($PSCmdlet.ParameterSetName -eq 'Left')
    { 
        $Left
    }
    else
    {
        -$Right
    }

    return [math]::Floor($x * [math]::Pow(2,$shift))
}

That makes use a little more readable:

PS> bitshift 32 -right 3
4
PS> bitshift 1 -left 3
8

Upvotes: 3

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