> On 5 Sep 2019, at 17:41, Georg Hagn <georg.h...@gmail.com> wrote:
>
> I have to implemet following external structure (extrakt from the
> german api Doku):
>
> typedef struct {
> /**@brief MUST be always 2. */
> uint32_t version;
>
> /** @brief Pointer to KeyStore -- Verweis auf den KeyStore, see
> EricGetHandleToCertificate(). */
> EricZertifikatHandle zertifikatHandle;
>
> /** @brief PIN für den KeyStore.*/
> const char *pin;
>
> /**
> * @brief MUST be NULL in my context
> Dieser muss ...
> In allen anderen Fällen muss hier NULL übergeben
> werden. Der Parameter abrufCode
> besteht aus 2 x 5 Zeichen, die mit "-" verbunden sind.
> Beispiel: "K6FG5-RS32P"
> */
> const char *abrufCode;
>
> } eric_verschluesselungs_parameter_t;
>
> My Problem is, that i have to assign a NULL - value to the attribute
> abrufCode.
> I have tried varies possibilities but I get always the error, that the
> attribute abrufCode must have the value NULL.
>
> " Extract from log-file:
> 019-09-05 17:08:52,257709[0x00007fe036a2f050] ERROR: Für die
> übermittelte Datenart ist die Angabe eines Abrufcodes nicht zulässig,
> daher muss für den Abrufcode der Wert NULL übergeben werden.
> 610001029"
>
> How do I assign a NULL value to an attribute in a FFIExternalStructure?
The problem is not that is an structure but that is a char *, which is
converted to a String in Pharo.
Ideally, a nil should be mapped to NULL in this cases, but this is not working
(never implemented).
Easiest workaround, just map abrufCode to void * instead char * (pointers are
always same size).
So you can have:
myStryct abrufCode: ExternalAddress null.
But of course, that will change the way you put the value there when *it is
not* a NULL:
myStryct abrufCode: ‘hello’ utf8Encoded copyWith 0.
(The copyWith: 0 is to ensure the void * will receive something with proper \0
finalisation)
Esteban
>
> Following my last attempt (extracted from the Pharo Booklet Colletion
> "Calling Foreign Functions with Pharo May 31,2018")
> I assign values not directly with the generated attributes but with
> "api???" attributes.
>
> FFIExternalStructure subclass: #ERiCVerschluesselungsParameter
> instanceVariableNames: ''
> classVariableNames: 'OFFSET_ABRUFCODE OFFSET_PIN OFFSET_VERSION
> OFFSET_ZERTIFIKATHANDLE'
> package: 'Bajoras-ERiC'!
>
>
> ERiCVerschluesselungsParameter class >> fieldsDesc [
>
> "ERiCVerschluesselungsParameter rebuildFieldAccessors"
>
> ^ #(
> uint32 version;
> ERiCZertifikatHandle * zertifikatHandle;
> char * pin;
> char * abrufCode;
> )
> ]
>
> ERiCVerschluesselungsParameter >> initialize [
>
> self
> apiVersion: 2;
> apiAbrufCode: nil;
> apiPin: 'mySecret'.
> ]
>
> ERiCVerschluesselungsParameter >> accessorMethods for: pin, version,
> abrufCode, zertifikatHandle ("This method were automatically
> generated")
>
> ERiCVerschluesselungsParameter >> apiAbrufCode: aCode [
>
> | codeSize anAbrufCode |
>
> codeSize := 11.
> anAbrufCode := FFIExternalArray externalNewType: 'char' size: codeSize.
> 1 to: codeSize do: [ :idx | anAbrufCode at: idx put: Character null ] .
>
> aCode ifNotNil: [
> aCode doWithIndex: [ :char :i | anAbrufCode at: i put: char ].
> ].
>
> self abrufCode: anAbrufCode.
>
> ]
>
> ERiCVerschluesselungsParameter >> apiPin: aPin [
>
> | newPin |
>
> newPin := FFIExternalArray externalNewType: 'char' size: aPin size.
> aPin doWithIndex: [ :char :i | newPin at: i put: char ].
>
> self pin: newPin.
> ]
>
>
> ERiCVerschluesselungsParameter >> apiVersion: aVersion [
>
> | cryptoVersion |
>
> cryptoVersion := 2.
> self version: cryptoVersion.
>
> ]
>
> Thanks,
> Georg Hagn
>
