Problem description

For DIET to match the client problem with a service, servers and clients must “speak the same language”, i.e., they must use the same problem description. A unified way to describe problems is to use a name and define its profile with the type diet_profile_t:

typedef struct {
  char*       pb_name;
  int         last_in, last_inout, last_out;
  diet_arg_t *parameters;
} diet_profile_t;

The field parameters consists of a diet_arg_t array of size . Arguments can be:

IN: The data are sent to the server. The memory is allocated by the user.

INOUT: The data are allocated by the user as for the IN arguments, then sent to the server and brought back into the same memory zone after the computation has completed, without any copy. Thus freeing this memory on the client side while the computation is performed on the server would result in a segmentation fault when the data are brought back onto the client.

OUT: The data are created on the server and brought back into a newly allocated memory zone on the client. This allocation is performed by DIET. After the call has returned, the user can find the result in the zone pointed at by the value field. Of course, DIET cannot guess how long the user will need these data, so the user must free the memory him/herself with diet_free_data.

The fields last_in, last_inout and last_out of the diet_profile_t structure respectively point at the indexes in the parameters array of the last IN, INOUT and OUT arguments.

Functions to create and destroy such profiles are defined with the prototypes below:

diet_profile_t *diet_profile_alloc(char* pb_name, int last_in, int last_inout, int last_out);
int diet_profile_free(diet_profile_t *profile);

The values of last_in, last_inout and last_out are respectively:

last_in: + number of input data.

last_inout: last_in number of inout data.

last_out: last_inout number of out data.