Mailing lists / fpc-pascal / 2011-04
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Hello list,
I'm trying to translate the following
union<https://github.com/ik5/sofia-sip/blob/master/src/lib/sui.inc#L199>to Pascal, but I do not understand it, and so does h2pas. How to translate it ?
Thanks,
Ido
LINESIP - Opening the source for communication
http://www.linesip.com
http://www.linesip.co.il
Can you post the original c code? You point to a file that seems to be a reworked output from h2pas. As it is now, it indeed doesn't make any sense. I would think the su_len,su_family,su_port should make up a record but they aren't.
I suggest you move the #defines inside the union declaration to somewhere before the union declaration. It'll double up the ifdef's but make the code so much more readable.
Actually it's my own code :) But here is the original header<http://sofia-sip.cvs.sourceforge.net/viewvc/sofia-sip/sofia-sip/libsofia-sip-ua/su/sofia-sip/su.h?revision=1.16&view=markup>, line 157. The question is how can I create this lines ?
Thanks,
Ido
Can you post the original c code? You point to a file that seems to be a reworked output…
Forget my previous reply. I found the original header file on sourceforge.
I have alse a better understanding now of what the code is supposed to do: in case DOCUMENTATION_ONLY is not defined, a reference to, for example, su_sockaddr_u.su_family will be subsstituted by
su_sockaddr_u.susa.sa_family.
You could use macros and do a {$define su_family:=susa.sa_family} with the following limitations:
- if you have variables or other record members named su_family, not part of the su_sockaddr_u record, they will be renamed also.
- it works only for the units that include your .inc file.
Using macros, the translation looks like
{$MACRO ON}
{$ifndef DOCUMENTATION_ONLY}
{$if SU_HAVE_SOCKADDR_SA_LEN 0}
{$define su_len:=su_sa.sa_len}
{$else}
{$define su_len:=su_array[0]}
{$endif}
{$define su_family:=su_sa.sa_family}
{$define su_port:=su_sin.sin_port}
{$define su_scope_id:=su_array32[6]}
{$endif}
type
su_sockaddr_u = record
case longint of
{$ifdef DOCUMENTATION_ONLY}
0 : ( su_len : byte );
1 : ( su_family : byte );
2 : ( su_port : word );
{$else}
3 : ( su_dummy : smallint );
{$endif}
4 : ( su_array : array[0..31] of char );
5 : ( su_array16 : array[0..15] of word );
6 : ( su_array32 : array[0..7] of longword );
7 : ( su_sa : sockaddr );
8 : ( su_sin : sockaddr_in );
{$if SU_HAVE_IN6 0}
9 : ( su_sin6 : sockaddr_in6 );
{$endif}
{$ifdef DOCUMENTATION_ONLY}
10 : ( su_scope_id : longword );
{$endif}
end;Question:
In case of DOCUMENTATION_ONLY not defined, does
su_sockaddr_u = record
(...)
1 : ( su_sa.sa_family : byte )
(...)
end;
really compile?
(From what I know about Pascal I would say: no)
Regards,
Sven
That is why it is conditional :
su_sockaddr_u = record
(...)
{$ifdef DOCUMENTATION_ONLY}
0 : ( su_len : byte );
1 : ( su_family : byte );
2 : ( su_port : word );
{$else}
3 : ( su_dummy : smallint );
{$endif}
(...)
end;Cheers, Ludo
Ahhh right... *bangs his head against the wall*
Regards,
Sven
Using macros, the translation looks like {$MACRO ON} {$ifndef DOCUMENTATION_ONLY} {$if…
I've done the following at the moment:
{$IFDEF SU_HAVE_SOCKADDR_SA_LEN}
// #define su_len su_sa.sa_len <- unsupported for now
{$ELSE}
// #define su_len su_array[0] <- unsupported for now
{$ENDIF}
// #define su_family su_sa.sa_family <- unsupported for
now
// #define su_port su_sin.sin_port <- unsupported for
now
// #define su_scope_id su_array32[6] <- unsupported for
now
su_sockaddr_u = record
case Byte of
0 : (su_dummy : cshort); //< Dummy
member to initialize
1 : (su_array : array[0..31] of char); //
Presented as chars
2 : (su_array16 : array[0..15] of cuint16); //
Presented as 16-bit ints
3 : (su_array32 : array[0..8] of cuint32); //
Presented as 32-bit ints
4 : (su_sa : sockaddr); //
Address in struct sockaddr format
5 : (su_sin : sockaddr_in); //
Address in IPv4 format
{$IFDEF SU_HAVE_IN6}
6 : (su_sin6 : sockaddr_in6); //
Address in IPv6 format
{$ENDIF}
end;As I understood by you and C developers that I talked to, the macro create a shortcut to be used.
Thanks,
Ido
OK . You have avoided using macros but are loosing the access to "pseudo" members su_len,su_family,su_port and su_scope_id. The DOCUMENTATION_ONLY suggests that these members are documented parts of the interface. Also it will be up to the user to figure out where to get su_len according to SU_HAVE_SOCKADDR_SA_LEN.
I can not find them in the preprocessor code (the define and the "document only" members), that's why I avoided them at this point. but if I'll find them required, I'll invest more time to add them.
I guess DOCUMENTATION_ONLY is defined in an external tool such as doxygen. Applications wouldn't define this. My point is that if the "pseudo" members are documented, someone will soon or later use them. If this header translation is for your personal
use only, then all is fine...