[redland-dev] C# binding encoding problem

[Victor Lindesay]

Hi Redlanders,

I have been taking my first steps into Redland using Chris Pointon's
VC++ project and Cesar Lopez Nataren's C# binding. I have got Redland to
compile and have made a simple C# app for loading RDF and making RDQL
queries. However I am having some problems with text encoding.

Firstly I had to make changes to the C# wrapper regarding passing
strings between managed and unmanaged code. I have had to change all
IntPtr pointer = Marshal.StringToHGlobalAuto(aString); lines to IntPtr
pointer = Marshal.StringToHGlobalAnsi(aString); and string aString =
Marshal.PtrToStringAuto(pointer); lines to string aString =
Marshal.PtrToStringAnsi(pointer);.
Otherwise any calls that pass strings to or return strings from librdf
do not work.

For example, without these changes, stepping through the C code I notice
that if I create a "rdfxml" parser, the line:
if(!strcmp(syntax_name, "rdfxml")) { ...
in
librdf_parser_raptor_constructor() fails.

However with the string marshalling changes I get various text encoding
problems. For example when I parse my FOAF file [1], loading from URL
with librdf_parser_parse_into_model(), and stream out the triples, all
my buddies with latin-1 characters come out wrong. Leandro Mariano López
comes out as Leandro Mariano López!

Also, if I pass my FOAF as a string to
librdf_parser_parse_string_into_model(), it loads all triples up to the
first with a latin-1 character then stops. This and all subsequent
triples are not parsed.

Am I doing something wrong compiling Redland? Or is it something on the
.Net side?

I am using .Net 1.1 on Windows 2003 and compiling Redland with VC++ 6.

[Please be gentle, I am a complete C newbie ;-)]

Regards,
Victor Lindesay

[1]
http://www.schemaweb.info/foaf/vlindesay.xml




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