Procedure

   size_c ( Size of a cell ) 

   SpiceInt size_c ( SpiceCell  * cell )

Abstract

   Return the size (maximum cardinality) of a SPICE cell of any
   data type.

Required_Reading

   CELLS
   SETS

Keywords

   CELLS
   SETS

Brief_I/O

   VARIABLE  I/O  DESCRIPTION
   --------  ---  --------------------------------------------------
   cell       I   Input cell.

   The function returns the size of the input cell.

Detailed_Input

   cell        is a SPICE cell of any data type.

               `cell' must be declared as a character, double precision or
               integer SpiceCell.

               CSPICE provides the following macros, which declare and
               initialize the cell

                  SPICECHAR_CELL          ( cell, CELLSZ, CELLMLEN );
                  SPICEDOUBLE_CELL        ( cell, CELLSZ );
                  SPICEINT_CELL           ( cell, CELLSZ );

               where CELLSZ is the maximum capacity of `cell' and CELLMLEN is
               the maximum length of any member in the character cell.

Detailed_Output

   The function returns the size of (maximum number of elements in)
   the input cell.

Parameters

   None.

Exceptions

   1)  If the input `cell' cell argument does not have a recognized data
       type, the error SPICE(NOTSUPPORTED) is signaled.

   2)  If the input `cell' has invalid cardinality, the error
       SPICE(INVALIDCARDINALITY) is signaled by a routine in the call
       tree of this routine. size_c returns an unspecified value in this
       case.

   3)  If the input `cell' has invalid size, the error
       SPICE(INVALIDSIZE) is signaled by a routine in the call tree of
       this routine. size_c returns an unspecified value in this case.

Files

   None.

Particulars

   None.

Examples

   The numerical results shown for this example may differ across
   platforms. The results depend on the SPICE kernels used as
   input, the compiler and supporting libraries, and the machine
   specific arithmetic implementation.

   1) The size_c function is typically used in conjunction
      with the card_c function to predict (and subsequently
      avoid) overflows when manipulating cells. In the following
      example, card_c and size_c are used to determine whether
      the union of two sets is safe.


      Example code begins here.


      /.
         Program size_ex1
      ./
      #include <stdio.h>
      #include "SpiceUsr.h"


      int main( )
      {

         /.
         Local constants.
         ./
         #define SETDIM       5

         /.
         Local variables.

         Declare two SPICE cells.
         ./
         SPICEINT_CELL      ( seta, SETDIM );
         SPICEINT_CELL      ( setb, SETDIM );
         SPICEINT_CELL      ( setc, SETDIM );

         SpiceInt             i;

         /.
         Create a list of items and even numbers.
         ./
         SpiceInt             even   [SETDIM] = {  0,  2,  4,  4,  8 };

         SpiceInt             items  [SETDIM] = {  0,  1,  1,  2,  8 };

         /.
         Initialize the empty sets.
         ./
         valid_c ( SETDIM, 0, &seta );
         valid_c ( SETDIM, 0, &setb );

         /.
         Insert `even' on `seta' and `items' on `setb'
         ./
         for ( i = 0; i < SETDIM; i++ )
         {
            insrti_c ( even[i],  &seta );
            insrti_c ( items[i], &setb );
         }

         /.
         Perform the union if possible.
         ./
         if ( card_c ( &seta ) + card_c ( &setb ) <= size_c ( &setc ) )
         {
            printf( "Union will not overflow the output set.\n" );
            union_c ( &seta, &setb, &setc );
         }
         else
         {
            printf( "Union may overflow...\n" );
            inter_c ( &seta, &setb, &setc );

            if ( card_c ( &seta ) + card_c ( &setb ) - card_c ( &setc ) <=
                 size_c ( &setc ) )
            {
               printf( "   ... but inter_c indicates it is safe!\n" );
               union_c ( &seta, &setb, &setc );
            }
            else
            {
               printf( "  ... and inter_c confirms it!\n" );
            }

         }

         return ( 0 );
      }


      When this program was executed on a Mac/Intel/cc/64-bit
      platform, the output was:


      Union may overflow...
         ... but inter_c indicates it is safe!

Restrictions

   None.

Literature_References

   None.

Author_and_Institution

   N.J. Bachman        (JPL)
   C.A. Curzon         (JPL)
   J. Diaz del Rio     (ODC Space)
   H.A. Neilan         (JPL)
   W.L. Taber          (JPL)
   I.M. Underwood      (JPL)

Version

   -CSPICE Version 1.0.1, 27-AUG-2021 (JDR)

       Edited the header to comply with NAIF standard. Added complete
       code example based on existing example fragments.

       Added SETS to the list of required readings and keywords.

       Extended description of argument "cell" in -Detailed_Input to include
       type and preferred declaration method.

       Added entry #1 in -Exceptions section.

   -CSPICE Version 1.0.0, 06-AUG-2002 (NJB) (CAC) (HAN) (WLT) (IMU)

Index_Entries

   size of a cell