[Libburn] Patch to enable arbitrary input fd (updated 2nd submission)

[scdbackup at gmx.net]

Hi,

i finally grasped what you meant with putting the size into .data .
Sorry for not knowing what my new constructor does exactly.


Yes, struct burn_source_file in file.h is a good place to
put (type_to_find) fixed_size .
Provided it is your intention to restrict fixed size setting to
sources of type  burn_source_file .

In that case, what about this : 

struct burn_source_file
{
        int datafd;
        type_to_find fixed_data_size;
        int subfd;
};

Then i would propose something like:

static int file_size(struct burn_source *source)
{
        struct stat buf;
        struct burn_source_file *fs = source->data;
        type_to_find size;

        if(fs->fixed_data_size > 0) {
                 size = fs->fixed_data_size;
        } else {
                 fstat(fs->datafd, &buf);
                 size = buf.st_size;
        }
        /* ??? what to do in case of size >= 2 GB ? */
        /* ??? return -1 , return 0 ? */
        return (int) size;
}

Unless the type of file_size() is changed to the type_to_find
there will be the need to invent an error return and a need to
interpret it by the callers.
Alternatively one could abort, but as application programmer
i would perceive this as somewhat rough.

This need is independent of my patch proposals.
Files of >= 2 GB are common.


Have a nice day :)

Thomas