BitAND for identifying file permissions

[joakim]

I made som code that will produce the right output, but I feel it is unnecessary long with BitAND and a bunch of If statements. So I was wondering if the same result could be achieved by BitOR? Here's what I've got;

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$input = 0x4001
$output = ""
$read_only = 0x0001
$hidden = 0x0002
$system = 0x0004
$archive = 0x0020
$device = 0x0040
$normal = 0x0080
$temporary = 0x0100
$sparse_file = 0x0200
$reparse_point = 0x0400
$compressed = 0x0800
$offline = 0x1000
$not_indexed = 0x2000
$encrypted = 0x4000

If BitAND($input,$read_only) Then
    $output &= 'read_only+'
EndIf
If BitAND($input,$hidden) Then
    $output &= 'hidden+'
EndIf
If BitAND($input,$system) Then
    $output &= 'system+'
EndIf
If BitAND($input,$archive) Then
    $output &= 'archive+'
EndIf
If BitAND($input,$device) Then
    $output &= 'device+'
EndIf
If BitAND($input,$normal) Then
    $output &= 'normal+'
EndIf
If BitAND($input,$temporary) Then
    $output &= 'temporary+'
EndIf
If BitAND($input,$sparse_file) Then
    $output &= 'sparse_file+'
EndIf
If BitAND($input,$reparse_point) Then
    $output &= 'reparse_point+'
EndIf
If BitAND($input,$compressed) Then
    $output &= 'compressed+'
EndIf
If BitAND($input,$offline) Then
    $output &= 'offline+'
EndIf
If BitAND($input,$not_indexed) Then
    $output &= 'not_indexed+'
EndIf
If BitAND($input,$encrypted) Then
    $output &= 'encrypted+'
EndIf

$output = StringMid($output,1,StringLen($output)-1)
ConsoleWrite("$output = " & $output & @crlf)

I want the result to be like; "read_only+encrypted".

Joakim

Edited August 5, 2011 by joakim

[Malkey]

Maybe like this.

Global $aFilePermissions[13][2] = [ _
        [0x0001, 'read_only'], _
        [0x0002, 'hidden'], _
        [0x0004, 'system'], _
        [0x0020, 'archive'], _
        [0x0040, 'device'], _
        [0x0080, 'normal'], _
        [0x0100, 'temporary'], _
        [0x0200, 'sparse_file'], _
        [0x0400, 'reparse_point'], _
        [0x0800, 'compressed'], _
        [0x1000, 'offline'], _
        [0x2000, 'not_indexed'], _
        [0x4000, 'encrypted']]
        
Global $input = 0x4001
Global $output = ""

For $i = 0 To UBound($aFilePermissions) - 1
    If BitAND($input, $aFilePermissions[$i][0]) Then $output &= $aFilePermissions[$i][1] & '+'
Next

$output = StringTrimRight($output, 1)
ConsoleWrite("$output = " & $output & @CRLF)

[hannes08]

How about running it in a loop?

$input = 0x4001
$output = ""

Dim $a_rights[15][2] = [ _
[14, 0], _
[0x0001, "read_only"], _
[0x0002, "hidden"], _
[0x0004, "system"], _
[0x0020, "archive"], _
[0x0040, "device"], _
[0x080, "normal"], _
[0x0100, "temporary"], _
[0x0200, "sparse_file"], _
[0x0400, "reparse_point"], _
[0x0800, "compressed"], _
[0x1000, "offline"], _
[0x2000, "not_indexed"], _
[0x4000, "encrypted"]]


For $i = 1 To $a_rights[0][0]
    If BitAND($input, $a_rights[$i][0]) Then $output &= $a_rights[$i][1] & " + "
Next
$output = StringTrimRight($output, 3)
ConsoleWrite("$output = " & $output & @crlf)

Edit: Well, somewhat too slow, eh?

Edited August 5, 2011 by Hannes123

[joakim]

Thanks guys.

It was very helpful to get examples of alternativ usage on this case. Unfortunately, for some strange reason, it seems like my sample performs faster.. Since the code will run in a huge loop about a 100.000 times (filesystem analysis), I must keep the fastest. But once again, thank you very much for the examples.

[hannes08]

Well, running 1.000.000 iterations it comes to a difference of 27s (our version) to 17s (your version).

This is another example of "AutoIT is not fast in loops".

But if you#re running over 100.000 of files the difference of 10 sec in difference wouldn't play a big role.

[joakim]

Yes the isolated diff on this particular code is not big at all, but in total with all calculations, the script will take about 10 minutes per 100 Mb of input, so I have to cut back on each part I can even though it's not much. Btw, it's an $MFT analyzer..

[BrewManNH]

Instead of using this style of statement:

If BitAND($input,$read_only) Then
    $output &= 'read_only+'
EndIf

Try it this way to see if the speed increases or not:

If BitAND($input,$read_only) Then $output &= 'read_only+'

It might be a slight bit faster this way, I seem to remember some timing tests that said an inline If statement was faster than a multi-line one. O it could have been the other way around, getting old has its drawbacks.

[ProgAndy]

If you want the fastest code, then you should stick to this: One-line Ifs are sligtly faster and each variable access needs time

$output = ""
If BitAND($input,1) Then $output &= 'read_only+'
If BitAND($input,2) Then $output &= 'hidden+'
If BitAND($input,4) Then $output &= 'system+'
If BitAND($input,0x20) Then $output &= 'archive+'
If BitAND($input,0x40) Then $output &= 'device+'
If BitAND($input,0x80) Then $output &= 'normal+'
If BitAND($input,0x100) Then $output &= 'temporary+'
If BitAND($input,0x200) Then $output &= 'sparse_file+'
If BitAND($input,0x400) Then $output &= 'reparse_point+'
If BitAND($input,0x800) Then $output &= 'compressed+'
If BitAND($input,0x1000) Then $output &= 'offline+'
If BitAND($input,0x2000) Then $output &= 'not_indexed+'
If BitAND($input,0x4000) Then $output &= 'encrypted+'
$output = StringTrimRight($output, 1)

Edited August 5, 2011 by ProgAndy

[joakim]

You are right about 1-line Ifs. It is a little bit faster. Just tested. Thanks.

[hannes08]

If you want to save time change the line where you cut the last char from the string from

$output = StringMid($output,1,StringLen($output)-1)

to

$output = StringtrimRight($output,1)

Edit: corrected what I really wanted to say (D'oh!)

Edited August 5, 2011 by Hannes123

[joakim]

I'm afraid I can't see any difference..

[joakim]

You are right. StringTrimRight seems slightly faster too. Thanks.