[redland-dev] C# binding encoding problem

[Victor Lindesay]

Hi Edd,

Thanks for your replies.

I have made a little progress with my Redland problems.

> > 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.
> 
> Hmm, this is interesting but not necessarily wrong. The *Auto
> methods marshal to and from Unicode on Windows.  You can't 
> use strcmp against Unicode strings and expect it to work, 
> except with UTF-8 encoded strings that only contain ASCII characters.

I have solved the problem creating Storage and Parser objects with
changes to the function prototypes that have string params or return
values using MarshalAs attributes instead of InPtr:

For example:

Old example:

[DllImport ("librdf")]
static extern IntPtr librdf_new_parser (IntPtr world, IntPtr name,
IntPtr mime_type, IntPtr uri); private Parser (World  world, string
name, string mime_type, Uri uri) {
	IntPtr iname = Marshal.StringToHGlobalAuto (name);
	IntPtr imime_type = Marshal.StringToHGlobalAuto (mime_type);
	if (uri == (Uri) null)
		parser = librdf_new_parser (world.Handle, iname,
imime_type, IntPtr.Zero);
	else
		parser = librdf_new_parser (world.Handle, iname,
imime_type, uri.Handle);
	Marshal.FreeHGlobal (iname);
	Marshal.FreeHGlobal (imime_type);
}

New examples:

[DllImport ("librdf")]
static extern IntPtr librdf_new_parser (IntPtr world,
[MarshalAs(UnmanagedType.LPStr)] string name,
[MarshalAs(UnmanagedType.LPStr)] string mime_type, IntPtr uri);

private Parser (World  world, string name, string mime_type, Uri uri) {
	if (uri == (Uri) null)
		parser = librdf_new_parser (world.Handle, name,
mime_type, IntPtr.Zero);
	else
		parser = librdf_new_parser (world.Handle, name,
mime_type, uri.Handle); }

and

[DllImport ("librdf")]
[return: MarshalAs(UnmanagedType.LPStr)]
static extern string librdf_node_to_string (IntPtr node);

public override string ToString ()
{
	return librdf_node_to_string (node);
}

No luck yet with returned strings with latin-1 chars.
Or passing the RDF in as a string even with the above changes.

For López I am getting the following bytes from the above
Node.ToString() method: 
[76][195][131][194][179][112][101][122]
I presume that [195][131][194][179] is the ó char.

I am pressing on and trying to write a .Net function to convert the
Redland output strings.