NAME

       rq_query - RaptorQ Query Functions

SYNOPSIS

       #include <lcrq.h>

       uint8_t rq_Al(const rq_t * const rq);
       uint64_t rq_F(const rq_t * const rq);
       uint16_t rq_K(const rq_t * const rq);
       uint16_t rq_KP(const rq_t * const rq);
       uint16_t rq_T(const rq_t * const rq);
       uint16_t rq_N(const rq_t * const rq);
       uint8_t rq_Z(const rq_t * const rq);

       Compile and link with -llcrq.

DESCRIPTION

       The RaptorQ query functions return the value of their respective RaptorQ parameters.

       F  Transfer  Length  (F): 40-bit unsigned integer.  A non-negative integer that is at most
       946270874880.  This is the transfer length of the object in units of octets.

       T Symbol Size (T): 16-bit unsigned integer.  A positive integer that is less  than  2^^16.
       This is the size of a symbol in units of octets. This MUST be a multiple of Al.

       Al A symbol alignment parameter (Al): 8-bit unsigned integer.

       Z The number of source blocks (Z): 16-bit unsigned integer.

       K The number of source symbols.

       KP (K') The number of source and padding symbols.

       The parameter rq must be a pointer to RaptorQ context initialized with rq_init(3)

RETURN VALUE

       These functions return the RQ parameters as unsigned integers.

ERRORS

       These functions do not return errors.

EXAMPLE

   Program source

       /* params - example program to create RaptorQ context and print derived parameters */

       #include <lcrq.h>
       #include <stdio.h>
       #include <stdlib.h>

       int usage(const char *progname)
       {
               fprintf(stderr, "usage: `%s F T`  (F = object size, T = symbol size)0, progname);
       }

       int main(int argc, char *argv[])
       {
               rq_t *rq;
               uint64_t F;
               uint16_t T, K, KP, N, Z;
               uint8_t Al;

               if (argc != 3) return usage(argv[0]);
               F = atoll(argv[1]);
               T = atoll(argv[2]);

               /* initialize RaptorQ context */
               rq = rq_init(F, T);

               /* Query parameters */
               K = rq_K(rq);
               KP = rq_KP(rq);
               N = rq_N(rq);
               Z = rq_Z(rq);

               /* free RaptorQ context */
               rq_free(rq);

               printf("F  %12lusize of object to encode (40 bits)0, F);
               printf("T  %12usymbol (payload) size0, T);
               printf("K  %12unumber of original symbols0, K);
               printf("K' %12unumber of symbols, including padding symbols0, KP);
               printf("N  %12unumber of sub-blocks0, N);
               printf("Z  %12unumber of blocks0, Z);

               return 0;
       }

       rq_free(rq); /* free context when done */

SEE ALSO

       rq_init(3), rq_free(3), rq_decode(3), rq_encode(3), rq_symbol(3), lcrq(7)