AIOStruct.au3 - DllStruct wrapper for AutoItObject UDF

[doudou]

I don't know if somebody else already had got this idea (I couldn't find anything similar in the forum). Anyway, I needed this functionality for another project and thought it would not hurt to share it.

This neat little UDF wraps DllStructs into an AutoItObject. This not only increases comfort and simplifies syntax when handling structs but also allows use structs as property or function parameter in objects.

Use it like this (more elaborate examples are attached):

#include <AIOStruct.au3>
_AutoItObject_Startup()
Dim $tagStruct = "int myInt; char myString[128]"
Dim $objStruct = AIOStruct_New($tagStruct)
$objStruct.myInt = 0
$objStruct.myString = "Blah"

Please note: wrapping structs into objects costs performance and memory, thus if some of it is important you'd be better off with the plain DllStruct.

Version 1.0.1

• AIOStruct: added StructSize property and ReadStruct() method
• AIOStruct_Usage: added example for ReadStruct()

Version 1.1.0

• AIOStructMgd: new wrapper with managed memory pointer
• AIOStructMgd_Usage: new example for AIOStructMgd

Version 1.1.1

• AIOStructMgd: GetPtr() is now possible for struct elements
• AIOStructMgd_Usage: example for GetPtr($element) added

Version 1.1.2

• AIOStruct: some missing type checks added
• AIOStructMgd: implemented dynamic memory allocation

AIOStruct_Usage.au3

AIOStructMgd_Usage.au3

AIOStruct.au3

AIOStructMgd.au3

Edited April 9, 2010 by doudou

[Kip]

How can I get get the pointer to the structure? (Besides copying the whole structure back to a regular DllStruct)

Edited April 7, 2010 by Kip

[doudou]

How can I get get the pointer to the structure? (Besides copying the whole structure back to a regular DllStruct)

There is no such pointer: the struct itself isn't (and cannot be) saved anywhere in the object, only data. This is due to limitations of AutotIt and - inherited wise - of AutoItObject, those limitations have driven me to writing this UDF in first place.

[trancexx]

You can do this when creating:

_AutoItObject_AddProperty($result, "__default__", $ELSCOPE_READONLY, Number(DllStructGetPtr($t)))

And get pointer (number) like this:

ConsoleWrite("---Address of structure (in form of number) = " & $objStruct() & @CRLF)

Right?

[ProgAndy]

The only problem is to save the DLLstruct somewhere... You'll have to use a global array I think.

[trancexx]

The only problem is to save the DLLstruct somewhere... You'll have to use a global array I think.

He can use _MemVirtualAlloc() if no pointer is passed and free it on destruction.

[doudou]

You can do this when creating:

_AutoItObject_AddProperty($result, "__default__", $ELSCOPE_READONLY, Number(DllStructGetPtr($t)))

And get pointer (number) like this:

ConsoleWrite("---Address of structure (in form of number) = " & $objStruct() & @CRLF)

Right?

Yeah.. but no... but yeah... but no (greetings from Viki Pollard)

This is dangerous thing to do as we have to ensure that that pointer is valid throughout the entire live cycle of the object, which we cannot. Besides this procedure would either bloat the UDF (additional property setter for each struct element are required) or we will end up with copying back the members to the struct again (only this time to the saved pointer).

[doudou]

The only problem is to save the DLLstruct somewhere... You'll have to use a global array I think.

I don't see this as a problem. Copying data at once in $obj.GetStruct() or reading DllStruct pointer and copying each member in an accessor - is there a significant difference? Only that the latter is much more complicated to maintain (access violations rising).

[ProgAndy]

I don't see this as a problem. Copying data at once in $obj.GetStruct() or reading DllStruct pointer and copying each member in an accessor - is there a significant difference? Only that the latter is much more complicated to maintain (access violations rising).

DLLStructs are not supported in AutoItObject. You can not return a struct from a function. If you return a pointer, the struct it is pointing to has to be saved at some place, too. A global variable is the only solution to do that in an Object-method for access from outside the function. Edited April 7, 2010 by ProgAndy

[doudou]

DLLStructs are not supported in AutoItObject. You can not return a struct from a function.

Exactly that was the motivation behind AIOStruct. I had a custom AIO that needed access to a struct internally, after fiddling with pointers and allocs for a while I decided to write AIOStruct, so I can do this:

Dim $objStruct = AIOStruct_New($tagStruct, $pointer)
Dim $obj = _AutoItObject_Create()
_AutoItObject_AddProperty($obj, "_Struct", $ELSCOPE_PRIVATE, $objStruct)

If you return a pointer, the struct it is pointing to has to be saved at some place, too. A global variable is the only solution to do that in an Object-method for access from outside the function.

I don't get it, WHY we need a solution? And for what? AIOStruct isn't intended to be a replacement for DllStruct, the original pointer isn't needed to achieve its goals. Period. Edited April 7, 2010 by doudou

[ProgAndy]

Alright. I misinterpreted your response, I thought you were thinking about a solution. Personally I don't see a reason to solve this, too.

[doudou]

I added 2 features missed in the 1st release (s. the top post).

[Kip]

How can I get get the pointer to the structure? (Besides copying the whole structure back to a regular DllStruct)

There is a reason why I asked that question...

I've tried to do this too. But because of that problem, suddenly all the pros (except cleaner syntax) just ran away.

[doudou]

There is a reason why I asked that question...

I've tried to do this too. But because of that problem, suddenly all the pros (except cleaner syntax) just ran away.

I'm sure there's a good reason for your question. But 1stly the idea behind the AIOStruct was not primarily to have cooler syntax but possibility using sturcts in object calls and properties without pointer mambo-jambo (s. my reply to ProgAndy) and 2ndly if you want to use AIOStruct like DLLStruct you still can do it - just some additional calls are needed (s. AIOStruct_Usage.au3).

And finally I think I gonna give in and create a second incarnation of AIOStruct which will make access to struct pointer easier (and will have some restrictions comparing to AIOStruct though).

[trancexx]

There is a sort of a "missing link" that would make creation of this kind of objects sensible. It's __name__ property for the object. It would be set to the name of the object function the code is currently running in.

You will see what I mean after consultations with others.

This would be valid syntax in that case:

$oTimeStruct = _AutoItObject_DllStructCreate($tagSYSTEMTIME)
DllCall("kernel32.dll", "none", "GetSystemTime", "ptr", $oTimeStruct())
$iYear = $oTimeStruct.Year ; reading
ConsoleWrite($iYear & @CRLF) ; print
$oTimeStruct.Year = 2011 ; setting
$iYear = $oTimeStruct.Year ; reading again
ConsoleWrite($iYear & @CRLF) ; print

And method dealing with setting or reading (for every 'element') would be something like this:

Func _MethodMain($oSelf, $vParam1 = 0, $vParam2 = 0)
    Local $sMethod = $oSelf.__name__
    Local $tStructure = DllStructCreate($oSelf.__tag__, $oSelf())
    Switch @NumParams
        Case 1
            Return Number(DllStructGetData($tStructure, $sMethod))
        Case 2
            If $oSelf.__propcall__ Then
                Return Number(DllStructSetData($tStructure, $sMethod, $vParam1))
            Else
                Return Number(DllStructGetData($tStructure, $sMethod, $vParam1))
            EndIf
        Case 3
            Return Number(DllStructSetData($tStructure, $sMethod, $vParam2, $vParam1))
    EndSwitch
EndFunc

edit: That's over-numbered lol

Edited April 8, 2010 by trancexx

[doudou]

There is a sort of a "missing link" that would make creation of these kind of objects sensible. It's __name__ property for the object. It would be set to the name of the object function the code is currently running in.

You will see what I mean after consultations with others.

This would be valid syntax in that case:

$oTimeStruct = _AutoItObject_DllStructCreate($tagSYSTEMTIME)
DllCall("kernel32.dll", "none", "GetSystemTime", "ptr", $oTimeStruct())
$iYear = $oTimeStruct.Year ; reading
ConsoleWrite($iYear & @CRLF) ; print
$oTimeStruct.Year = 2011 ; setting
$iYear = $oTimeStruct.Year ; reading again
ConsoleWrite($iYear & @CRLF) ; print

Ah? Did I miss an AutoItObject release? Where did this _AutoItObject_DllStructCreate come from? Edited April 8, 2010 by doudou

[trancexx]

Ah? Did I miss an AutoItObject release? Where did this _AutoItObject_DllStructCreate come from?

I made it up 10 minutes ago

edit: actually 15-20

Edited April 8, 2010 by trancexx

[doudou]

By (popular?) demand I added a subclass of AIOStruct with managed memory and GetPtr() method (s. top post).

This is the closest thing to DllStruct I see possible for now. Maybe if the fog around trancexx' comments clears a bit we can talk about default properties.

[doudou]

There is a sort of a "missing link" that would make creation of this kind of objects sensible. It's __name__ property for the object. It would be set to the name of the object function the code is currently running in.

Slowly I begin to follow...

Well, this is imagined future of AutoItObject we are talking about, isn't it? Even if AIO supported that (what would be super), I actually would want to avoid property getters for struct elements though a single default getter for a __name__ would certainly reduce memory footprint.

[trancexx]

Slowly I begin to follow...

Well, this is imagined future of AutoItObject we are talking about, isn't it? Even if AIO supported that (what would be super), I actually would want to avoid property getters for struct elements though a single default getter for a __name__ would certainly reduce memory footprint.

Actually, my part is over. To the others now...