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[FFI] moving large memory

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Nicolas Cellier-3

[FFI] moving large memory

I want to transfer some memory between an ExternalAdress holding an array of
anything and Smalltalk memory (ByteArray for example).

I did figure well how to do it element by element, but didn't find anything
really efficient as a memcopy for example...

Does anyone have a clue, a package, a howto or something for me?
Thanks

Nicolas

Alan Grimes-2

Re: [FFI] moving large memory

nicolas cellier wrote:
> I want to transfer some memory between an ExternalAdress holding an array of
> anything and Smalltalk memory (ByteArray for example).
>
> I did figure well how to do it element by element, but didn't find anything
> really efficient as a memcopy for example...
>
> Does anyone have a clue, a package, a howto or something for me?
> Thanks

Common practice is to use BitBlt from the graphics system. I don't like
that solution for obvious reasons but I'm sure you can find some example
code...

--
Don't let your schoolwork get in the way of your learning.

### NEW E-MAIL: [hidden email] ###

Andreas.Raab

Re: [FFI] moving large memory

In reply to this post by Nicolas Cellier-3

Hi Nicolas -

Currently, there isn't any such method. The best thing you can do is to
call memcpy directly from your libc or so (assuming you're on a system
that gives you access to it - on windows you might have to use
MoveMemory or somesuch).

Cheers,
- Andreas

nicolas cellier wrote:

> I want to transfer some memory between an ExternalAdress holding an array of
> anything and Smalltalk memory (ByteArray for example).
>
> I did figure well how to do it element by element, but didn't find anything
> really efficient as a memcopy for example...
>
> Does anyone have a clue, a package, a howto or something for me?
> Thanks
>
> Nicolas
>
>
>

Nicolas Cellier-3

Re: [FFI] moving large memory

In reply to this post by Alan Grimes-2

Le Mercredi 17 Mai 2006 02:21, Alan Grimes a écrit :
> Common practice is to use BitBlt from the graphics system. I don't like
> that solution for obvious reasons but I'm sure you can find some example
> code...

Alan, thanks,
it seems convenient to move memory from Smalltalk to Smalltalk,
but i did not see any example using an ExternalAddress.
Since ExternalAddress are ByteArray with four bytes containing the address,
i'am afraid it won't be interpreted as a pointer, but an array of 32bits...
Or maybe i am wrong?

Le Mercredi 17 Mai 2006 05:46, Andreas Raab a écrit :
> Hi Nicolas -
>
> Currently, there isn't any such method. The best thing you can do is to
> call memcpy directly from your libc or so (assuming you're on a system
> that gives you access to it - on windows you might have to use
> MoveMemory or somesuch).
>
> Cheers,
> - Andreas

Andreas, thanks
but then how do i gain pointer access to data through smalltalk oop?
Is there another way but writing a plugin?
If i must write a plugin, i suggest this kind of basic service being included
in future FFI releases.

Nicolas

johnmci

Re: [FFI] moving large memory

On 17-May-06, at 4:47 AM, nicolas cellier wrote:

>
> Alan, thanks,
> it seems convenient to move memory from Smalltalk to Smalltalk,
> but i did not see any example using an ExternalAddress.
> Since ExternalAddress are ByteArray with four bytes containing the
> address,
> i'am afraid it won't be interpreted as a pointer, but an array of
> 32bits...
> Or maybe i am wrong?

In Sophie before using a Quicktime call to write bits into an
external display surface we moved data from a a quicktime GWorld into
a instance of Form
using the original mac os blockmovedata call which btw resolves to
bcopy.

fields
"MacPixMapHandle defineFields"
^#((nil 'long'))

updateOffscreenForm
| src dataSize |
src := self pixMapHandle getPixBaseAddr. "This returns a a memory
address"

dataSize := (self offscreenForm width * 4) * self offscreenForm height.
SophieQuickTimeInterface apiBlockMoveData: src dest: (self
offscreenForm bits) size: dataSize

"self offscreenForm bits points to the ByteArray of the Form"

apiBlockMoveData: srcPtr dest:destPtr size:size
<cdecl: void 'BlockMoveData' (long long* long )
module:'Carbon.framework'>
^ self externalCallFailed

"void BlockMoveData (
const void * srcPtr,
void * destPtr,
Size byteCount
); "

--
========================================================================
===
John M. McIntosh <[hidden email]> 1-800-477-2659
Corporate Smalltalk Consulting Ltd. http://www.smalltalkconsulting.com
========================================================================
===

Nicolas Cellier-3

Re: [FFI] moving large memory

Thanks John,

I hadn't understood that the ByteArray can be simply passed as char* and
WordArray as long* in FFI, so your tip helped me a lot.

Le Mercredi 17 Mai 2006 13:47, nicolas cellier a écrit :
> Andreas, thanks
> but then how do i gain pointer access to data through smalltalk oop?
> Is there another way but writing a plugin?
>
> Nicolas

Yes, i understand at last FFI do that for us.
Apologies to Andreas for my being a little slow-brained, his solution was
good.

Nicolas

Le Mercredi 17 Mai 2006 18:55, John M McIntosh a écrit :

> On 17-May-06, at 4:47 AM, nicolas cellier wrote:
> > Alan, thanks,
> > it seems convenient to move memory from Smalltalk to Smalltalk,
> > but i did not see any example using an ExternalAddress.
> > Since ExternalAddress are ByteArray with four bytes containing the
> > address,
> > i'am afraid it won't be interpreted as a pointer, but an array of
> > 32bits...
> > Or maybe i am wrong?
>
> In Sophie before using a Quicktime call to write bits into an
> external display surface we moved data from a a quicktime GWorld into
> a instance of Form
> using the original mac os blockmovedata call which btw resolves to
> bcopy.
>
> fields
> "MacPixMapHandle defineFields"
> ^#((nil 'long'))
>
>
> updateOffscreenForm
>
> | src dataSize |
>
> src := self pixMapHandle getPixBaseAddr. "This returns a a memory
> address"
>
> dataSize := (self offscreenForm width * 4) * self offscreenForm height.
> SophieQuickTimeInterface apiBlockMoveData: src dest: (self
> offscreenForm bits) size: dataSize
>
> "self offscreenForm bits points to the ByteArray of the Form"
>
>
> apiBlockMoveData: srcPtr dest:destPtr size:size
> <cdecl: void 'BlockMoveData' (long long* long )
> module:'Carbon.framework'>
> ^ self externalCallFailed
>
>
>
> "void BlockMoveData (
> const void * srcPtr,
> void * destPtr,
> Size byteCount
> ); "
>
>
>
> --
> ========================================================================
> ===
> John M. McIntosh <[hidden email]> 1-800-477-2659
> Corporate Smalltalk Consulting Ltd. http://www.smalltalkconsulting.com
> ========================================================================
> ===