Function to return consumed space in regular and compressed values, for windows deduplication

Get-ConsumedSpace.ps1

function Get-ConsumedSpace
{
        #.Synopsis
        # Get folders, and space consumed by each
    [cmdletbinding()]
    param(
            # Target Location
            [Parameter(Mandatory=$True)]
            [string]$folder,
            [switch]$inGB

        )

    try 
    {
        [Win32Functions.ExtendedFileInfo] | Out-Null
    }
    catch
    {
     # Gleefully lifted from https://stackoverflow.com/questions/554010/how-to-get-the-actual-size-on-disk-of-a-file-from-powershell
     
     add-type -type  @'
        using System;
        using System.Runtime.InteropServices;
        using System.ComponentModel;

        namespace Win32Functions
        {
            public class ExtendedFileInfo
            {
                [DllImport("kernel32.dll", SetLastError=true, EntryPoint="GetCompressedFileSize")]
                static extern uint GetCompressedFileSizeAPI(string lpFileName, out uint lpFileSizeHigh);

                public static ulong GetCompressedFileSize(string filename)
                {
                    uint high;
                    uint low;
                    low = GetCompressedFileSizeAPI(filename, out high);
                    int error = Marshal.GetLastWin32Error();
                    if (high == 0 && low == 0xFFFFFFFF && error != 0)
                    throw new Win32Exception(error);
                    else
                    return ((ulong)high << 32) + low;
                }
            }
        }
'@
}
    function Get-CFS
    {
        Param($path)
        [Win32Functions.ExtendedFileInfo]::GetCompressedFileSize((Get-Item $path).FullName)
    }


    
    New-PSDrive -Name "space" -PSProvider FileSystem -Root $folder | Out-Null # Dodging Char Limits 101    
	$filelist = Get-ChildItem -force -recurse space:\ | select Length, @{Name='CompressedLength';e={ [Win32Functions.ExtendedFileInfo]::GetCompressedFileSize($_.FullName) }}
    $Size = $filelist | Measure-Object -property length -sum
    $CFSize = $filelist | Measure-Object -Property CompressedLength -sum
    
    

    if ($inGB -eq $false)
    {
        $thisObject = "derp" | Select-Object @{Name="UFSize";e={$Size.sum}},`
                                    @{Name="CFSize";e={$CFSize.sum}},`
                                    @{Name="Count";e={$size.count}}
        Return $thisObject
    }
    else
    {
        ######### Make the size number human readable GB
        $thisObject = "derp" | Select-Object @{Name="UFSize";e={"{0:N2}" -f ($Size.sum / 1GB)}},`
                                            @{Name="CFSize";e={"{0:N2}" -f ($CFSize.sum / 1GB)}},`
                                            @{Name="Count";e={$size.count}}
        Return $thisObject
    }
}