* Lepton EDA 1.9.14 announce and misc questions
@ 2021-04-20 9:29 Vladimir Zhbanov
2021-04-20 12:47 ` Matt Wette
0 siblings, 1 reply; 6+ messages in thread
From: Vladimir Zhbanov @ 2021-04-20 9:29 UTC (permalink / raw)
To: guile-user
Hi Guile users and devs,
I'm the current maintainer of Lepton EDA suite, an about five year
old fork of geda-gaf with accent to moving more functionality to
Scheme code. I'm not sure if it is acceptable to advertise it
here, please let me know if not. I just know several Guix
packagers are reading this mailing list and would like to announce
a new version of Lepton, 1.9.14 has been released on April, 7:
https://github.com/lepton-eda/lepton-eda/releases/tag/1.9.14-20210407
Lepton supports Guile 2.0, 2.2, and 3.0. There are lots of C code
involved and one of our current goals is untangling it and moving
our Scheme functionality to FFI as much as possible. Hence, the
issue I recently stumbled upon.
Having the following code:
(define-public (sys-data-dirs)
"Returns a list of search directories for system data."
(let ((pointer (eda_get_system_data_dirs)))
(let loop ((num 0)
(ls '()))
(let ((string-pointer
(dereference-pointer
(make-pointer (+ (pointer-address pointer)
(* num (alignof '*)))))))
(if (null-pointer? string-pointer)
(reverse ls)
(loop (1+ num)
(cons (pointer->string string-pointer)
ls)))))))
is it permissible to use 'alignof' (or 'sizeof') this way here, if
at all? Or some pitfalls may exist?
The function gets the C array of strings and translates them into
a Scheme list. I just don't want to write an additional C layer
to process the array, but I'm in doubt if it could shoot me in the
foot on some OS/arch combinations.
Thanks in advance,
Vladimir
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: Lepton EDA 1.9.14 announce and misc questions
2021-04-20 9:29 Lepton EDA 1.9.14 announce and misc questions Vladimir Zhbanov
@ 2021-04-20 12:47 ` Matt Wette
2021-04-20 13:46 ` Matt Wette
0 siblings, 1 reply; 6+ messages in thread
From: Matt Wette @ 2021-04-20 12:47 UTC (permalink / raw)
To: guile-user
On 4/20/21 2:29 AM, Vladimir Zhbanov wrote:
> Hi Guile users and devs,
>
> I'm the current maintainer of Lepton EDA suite, an about five year
> old fork of geda-gaf with accent to moving more functionality to
> Scheme code. I'm not sure if it is acceptable to advertise it
> here, please let me know if not. I just know several Guix
> packagers are reading this mailing list and would like to announce
> a new version of Lepton, 1.9.14 has been released on April, 7:
>
> https://github.com/lepton-eda/lepton-eda/releases/tag/1.9.14-20210407
>
>
Sweet. Thanks for posting this. I will take a look at your problem.
It'll require digging into the eda_..._dirs function.
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: Lepton EDA 1.9.14 announce and misc questions
2021-04-20 12:47 ` Matt Wette
@ 2021-04-20 13:46 ` Matt Wette
2021-04-20 23:36 ` Vladimir Zhbanov
0 siblings, 1 reply; 6+ messages in thread
From: Matt Wette @ 2021-04-20 13:46 UTC (permalink / raw)
To: guile-user
On 4/20/21 5:47 AM, Matt Wette wrote:
>
>
> On 4/20/21 2:29 AM, Vladimir Zhbanov wrote:
>> Hi Guile users and devs,
>>
>> I'm the current maintainer of Lepton EDA suite, an about five year
>> old fork of geda-gaf with accent to moving more functionality to
>> Scheme code. I'm not sure if it is acceptable to advertise it
>> here, please let me know if not. I just know several Guix
>> packagers are reading this mailing list and would like to announce
>> a new version of Lepton, 1.9.14 has been released on April, 7:
>>
>> https://github.com/lepton-eda/lepton-eda/releases/tag/1.9.14-20210407
>>
>>
>
> Sweet. Thanks for posting this. I will take a look at your problem.
> It'll require digging into the eda_..._dirs function.
>
>
>
The following should work as a complete program on a system w/ glib.
You need to first convert the result to a bytevector and then access the
elements (pointers) one at a time. Note that we don't know how big the
array returned from the C function is. I pick an oversized value of 100.
(use-modules (system foreign))
(use-modules (rnrs bytevectors))
(define glib (dynamic-link "libglib-2.0"))
(define g-get-system-data-dirs
(let ((f (pointer->procedure
'* (dynamic-func "g_get_system_data_dirs" glib) (list)))
(bv-pointer-ref (cond
((= (sizeof '*) 8) bytevector-u64-native-ref )
((= (sizeof '*) 4) bytevector-u32-native-ref )
(else (error "hmmm"))))
(BIG 100))
(lambda ()
(let* ((r (f))
(p (pointer->bytevector r (* BIG (sizeof '*)))))
(let loop ((ix 0))
(let* ((ad (bv-pointer-ref p ix))
(sp (make-pointer ad)))
(if (equal? %null-pointer sp)
'()
(cons (pointer->string sp) (loop (+ ix (sizeof '*)))))))))))
(simple-format #t "~S" (g-get-system-data-dirs))
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: Lepton EDA 1.9.14 announce and misc questions
2021-04-20 13:46 ` Matt Wette
@ 2021-04-20 23:36 ` Vladimir Zhbanov
2021-04-21 0:34 ` Matt Wette
0 siblings, 1 reply; 6+ messages in thread
From: Vladimir Zhbanov @ 2021-04-20 23:36 UTC (permalink / raw)
To: guile-user
Hi Matt,
On Tue, Apr 20, 2021 at 06:46:27AM -0700, Matt Wette wrote:
>
>
> On 4/20/21 5:47 AM, Matt Wette wrote:
> >
> >
> > On 4/20/21 2:29 AM, Vladimir Zhbanov wrote:
> > > Hi Guile users and devs,
> > >
> > > I'm the current maintainer of Lepton EDA suite, an about five year
> > > old fork of geda-gaf with accent to moving more functionality to
> > > Scheme code. I'm not sure if it is acceptable to advertise it
> > > here, please let me know if not. I just know several Guix
> > > packagers are reading this mailing list and would like to announce
> > > a new version of Lepton, 1.9.14 has been released on April, 7:
> > >
> > > https://github.com/lepton-eda/lepton-eda/releases/tag/1.9.14-20210407
> > >
> > >
> >
> > Sweet. Thanks for posting this. I will take a look at your problem.
> > It'll require digging into the eda_..._dirs function.
> >
> >
> >
> The following should work as a complete program on a system w/ glib.
> You need to first convert the result to a bytevector and then access the
> elements (pointers) one at a time. Note that we don't know how big the
> array returned from the C function is. I pick an oversized value of 100.
>
> (use-modules (system foreign))
> (use-modules (rnrs bytevectors))
>
> (define glib (dynamic-link "libglib-2.0"))
>
> (define g-get-system-data-dirs
> (let ((f (pointer->procedure
> '* (dynamic-func "g_get_system_data_dirs" glib) (list)))
> (bv-pointer-ref (cond
> ((= (sizeof '*) 8) bytevector-u64-native-ref )
> ((= (sizeof '*) 4) bytevector-u32-native-ref )
> (else (error "hmmm"))))
> (BIG 100))
> (lambda ()
> (let* ((r (f))
> (p (pointer->bytevector r (* BIG (sizeof '*)))))
> (let loop ((ix 0))
> (let* ((ad (bv-pointer-ref p ix))
> (sp (make-pointer ad)))
> (if (equal? %null-pointer sp)
> '()
> (cons (pointer->string sp) (loop (+ ix (sizeof '*)))))))))))
>
> (simple-format #t "~S" (g-get-system-data-dirs))
Thank you for your replies!
Probably, I missed something here, so I'll try to elaborate a bit
on my initial question. The function eda_get_system_data_dirs()
mentioned in my first message has the same type, is defined the
same way using dynamic-func though in liblepton instead of glib,
and works on mostly the same array as glib's
g_get_system_data_dirs(). The function I've shown works well and
outputs the same results as yours. It simply uses a bit more
upper level interface, IIUC. So the first question is: I wonder,
if using bytevectors directly adds something here?
Another issue is a little more confusing for me. I read in
several places that even on the same system different compilators,
say gcc and g++, may use different alignment even for basic C
types like, say, double. What will they do on different platforms
then? May it be that (alignof '*) will be twice greater than
(sizeof '*)? In such a case using multiplied sizeof of pointer
for searching the location of a pointer in memory would be just
dangerous. I used sizeof in the first version of my code but
started to doubt if it is correct and how portable it is.
Thanks,
Vladimir
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: Lepton EDA 1.9.14 announce and misc questions
2021-04-20 23:36 ` Vladimir Zhbanov
@ 2021-04-21 0:34 ` Matt Wette
2021-04-21 7:53 ` Vladimir Zhbanov
0 siblings, 1 reply; 6+ messages in thread
From: Matt Wette @ 2021-04-21 0:34 UTC (permalink / raw)
To: guile-user
On 4/20/21 4:36 PM, Vladimir Zhbanov wrote:
> Hi Matt,
>
> On Tue, Apr 20, 2021 at 06:46:27AM -0700, Matt Wette wrote:
>>
>> On 4/20/21 5:47 AM, Matt Wette wrote:
>>>
>>> On 4/20/21 2:29 AM, Vladimir Zhbanov wrote:
>>>> Hi Guile users and devs,
>>>>
>>>> I'm the current maintainer of Lepton EDA suite, an about five year
>>>> old fork of geda-gaf with accent to moving more functionality to
>>>> Scheme code. I'm not sure if it is acceptable to advertise it
>>>> here, please let me know if not. I just know several Guix
>>>> packagers are reading this mailing list and would like to announce
>>>> a new version of Lepton, 1.9.14 has been released on April, 7:
>>>>
>>>> https://github.com/lepton-eda/lepton-eda/releases/tag/1.9.14-20210407
>>>>
>>>>
>>> Sweet. Thanks for posting this. I will take a look at your problem.
>>> It'll require digging into the eda_..._dirs function.
>>>
>>>
>>>
>> The following should work as a complete program on a system w/ glib.
>> You need to first convert the result to a bytevector and then access the
>> elements (pointers) one at a time. Note that we don't know how big the
>> array returned from the C function is. I pick an oversized value of 100.
>>
>> (use-modules (system foreign))
>> (use-modules (rnrs bytevectors))
>>
>> (define glib (dynamic-link "libglib-2.0"))
>>
>> (define g-get-system-data-dirs
>> (let ((f (pointer->procedure
>> '* (dynamic-func "g_get_system_data_dirs" glib) (list)))
>> (bv-pointer-ref (cond
>> ((= (sizeof '*) 8) bytevector-u64-native-ref )
>> ((= (sizeof '*) 4) bytevector-u32-native-ref )
>> (else (error "hmmm"))))
>> (BIG 100))
>> (lambda ()
>> (let* ((r (f))
>> (p (pointer->bytevector r (* BIG (sizeof '*)))))
>> (let loop ((ix 0))
>> (let* ((ad (bv-pointer-ref p ix))
>> (sp (make-pointer ad)))
>> (if (equal? %null-pointer sp)
>> '()
>> (cons (pointer->string sp) (loop (+ ix (sizeof '*)))))))))))
>>
>> (simple-format #t "~S" (g-get-system-data-dirs))
> Thank you for your replies!
>
> Probably, I missed something here, so I'll try to elaborate a bit
> on my initial question. The function eda_get_system_data_dirs()
> mentioned in my first message has the same type, is defined the
> same way using dynamic-func though in liblepton instead of glib,
> and works on mostly the same array as glib's
> g_get_system_data_dirs(). The function I've shown works well and
> outputs the same results as yours. It simply uses a bit more
> upper level interface, IIUC. So the first question is: I wonder,
> if using bytevectors directly adds something here?
>
> Another issue is a little more confusing for me. I read in
> several places that even on the same system different compilators,
> say gcc and g++, may use different alignment even for basic C
> types like, say, double. What will they do on different platforms
> then? May it be that (alignof '*) will be twice greater than
> (sizeof '*)? In such a case using multiplied sizeof of pointer
> for searching the location of a pointer in memory would be just
> dangerous. I used sizeof in the first version of my code but
> started to doubt if it is correct and how portable it is.
>
> Thanks,
> Vladimir
>
Hey. I used the glib routine because it returns the same form,
if I read correctly. The return value is a pointer to a sequence
of (C) pointers. On my machine they are 8 bytes each. So, if
the function is returning three strings, say, the first 8 bytes will
be a pointer to the first string and last 8 bytes (of a total of 32
= 4 * 8) will be zero. You need to access the three 8-byte
pointer values as numbers and convert to guile pointers to
access the strings. I don't see a way around that.
I don't see this being a problem with gcc vs g++. Maybe in
structs with mixed types, but not here, IMO.
Matt
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: Lepton EDA 1.9.14 announce and misc questions
2021-04-21 0:34 ` Matt Wette
@ 2021-04-21 7:53 ` Vladimir Zhbanov
0 siblings, 0 replies; 6+ messages in thread
From: Vladimir Zhbanov @ 2021-04-21 7:53 UTC (permalink / raw)
To: guile-user
On Tue, Apr 20, 2021 at 05:34:59PM -0700, Matt Wette wrote:
...
> Hey. I used the glib routine because it returns the same form,
> if I read correctly. The return value is a pointer to a sequence
> of (C) pointers. On my machine they are 8 bytes each. So, if
> the function is returning three strings, say, the first 8 bytes will
> be a pointer to the first string and last 8 bytes (of a total of 32
> = 4 * 8) will be zero. You need to access the three 8-byte
> pointer values as numbers and convert to guile pointers to
> access the strings. I don't see a way around that.
>
> I don't see this being a problem with gcc vs g++. Maybe in
> structs with mixed types, but not here, IMO.
I'm much relieved to hear it, thank you for your time.
Vladimir
^ permalink raw reply [flat|nested] 6+ messages in thread
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2021-04-20 9:29 Lepton EDA 1.9.14 announce and misc questions Vladimir Zhbanov
2021-04-20 12:47 ` Matt Wette
2021-04-20 13:46 ` Matt Wette
2021-04-20 23:36 ` Vladimir Zhbanov
2021-04-21 0:34 ` Matt Wette
2021-04-21 7:53 ` Vladimir Zhbanov
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