[Gtk-sharp-list] Marshaling question

[Paolo Molaro]

On 02/27/03 Charles Iliya Krempeaux wrote:
> I am creating C# a method with the following signature:
> 
>    public override int Read(byte[] buffer, int offset, int count);
> 
> Here, "buffer" (will eventually) contain the stuff that got read.  
> "offset" tells you where to start storing stuff in "buffer".
> ("offset" used a zero based index.)  And "count" is the maximun
> number of bytes to read from the current stream.  Also, it returns
> the total number of bytes read from the stream.
> 
> Now, I'm using this to wrap the GnomeVFS procedure:
> 
>   GnomeVFSResult gnome_vfs_read(GnomeVFSHandle   *handle      ,
>                                 gpointer          buffer      ,
>                                 GnomeVFSFileSize  bytes       ,
>                                 GnomeVFSFileSize *bytes_read );
> 
> The problem I am having is with "buffer" in "gnome_vfs_read".  I
> need to get a the get at the pointer for "Read"'s buffer.  In
> pseudo code, this is basically what I want to do...
> 
>     public override int Read(byte[] buffer, int offset, int count)
>     {
> 
>         byte * bufferptr = (byte * ) buffer;
> 
>         bufferptr = bufferptr + offset;
> 
>         // ...
> 
> Although, I am not sure how to do this.  Anyone here have any
> ideas?
> 
> (I.e., anyone know how to get a pointer to "buffer"'s memory
> buffer?)

Use:
	fixed (byte *ss = &buffer [offset]) {
		gnome_vfs_read (handle, ss, ...);
	}

Give or take the proper declaration for gnome_vfs_read.

lupus

-- 
-----------------------------------------------------------------
lupus@debian.org                                     debian/rules
lupus@ximian.com                             Monkeys do it better