Questions ad marshalling multi-dimensional arrays

[rony]

Sorry, while changing the sample in the process of formulating the
questions the remaining sample data were posted wrongly in my last mail! :(

On 23.06.2011 12:13, rony wrote:
> Hi there,
>
> while contemplating the marshalling of multidimensional arrays I could
> not find definitive answers, hence turning to this list, requesting
> some answers (even as short as "yes" and "no"):
>
>     * given an array with two dimensions (signature: aas) and the
>       following set elements:
>
>           arr[0,0]="a"
>           arr[0,1]="b"
>           arr[0,2]="c"
>           arr[1,0]="A"  /* no values for:           arr[1,1], arr[1,2] */
>           arr[2,2]="3"  /* no values for: arr[2,0], arr[2,1]           */
>                   
>
Maybe a matrix form depicts the array better, where "-" indicates no
entry/empty:

    x/y |  0  1  2
    ----+----------
    0   |  a  b  c
    1   |  A  -  - 
    2   |  -  -  3
      

>    *
>
>     * Questions:
>           o Unassigned elements (like arr[1,0], which in some
>             languages could be marked explicitly as NULL/.nil) cannot
>             be dropped (left-out) ?
>
The above array should read: "... (like arr[1,1] ...".


>                 + If must be given, then short of an explicit
>                   NULL/.nil sentinel value one needs to use
>                       # An empty (0-length) string for string-like
>                         types (string, object_path, signature) ?
>                       # The value 0 for all simple types?
>
>           o Which would be the marshalling sequence in the above
>             example, assuming that unassigned elements are represented
>             by empty strings in this case?
>                1. [0,0], [0,1], [0,2], [1,0], [1,1], [1,2], [2,0],
>                   [2,1], [2,2], hence the element sequence: "a", "b",
>                   "c",  "A", "", "",  "", "", "3" ?
>                   or:
>                2. [0,0], [1,0], [2,0], [1,1], [2,1], [3,1], [1,2],
>                   [2,2], [2,3] hence the element sequence: "a", "A",
>                   "", "b", "", "", "c", "", "3" ?
>
The "2." above should read:

    2. [0,0], [1,0], [2,0], [0,1], [1,1], [2,1], [0,2], [1,2], [2,2]
    hence the element sequence: "a", "A", "", "b", "", "", "c", "", "3" ?


>           o Given the above example, would it be o.k. to leave out
>             "trailing empty elements of the array"?
>             E.g. in case 1. marshalling above, this would yield the
>             sequence (arr[1,1] and arr[1,2] are left out; the array's
>             dimension can still be defined by
>             open_container/close_container):
>                1. [0,0], [0,1], [0,2], [1,0], [1,1], [2,0], [2,1],
>                   [2,2], hence the element sequence: "a", "b", "c", 
>                   "A",  "", "", "3"
>
The above should read:

    [0,0], [0,1], [0,2], [1,0], [2,0], [2,1], [2,2], hence the element
    sequence: "a", "b", "c",  "A",  "", "", "3"


>           o Is it possible to marshall an empty array by merely using
>             a sequence of open_container(DBUS_TYPE_ARRAY) - no-content
>             - close_container?
>             (Thought that it was prohibited, but have not been able to
>             find references for this)?
>
Again, sorry for the confusing data in my initial mail.

What would be the answers?

---rony
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.freedesktop.org/archives/dbus/attachments/20110623/b3fb2597/attachment.html>