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dafgn_c
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Procedure
Abstract
Required_Reading
Keywords
Brief_I/O
Detailed_Input
Detailed_Output
Parameters
Exceptions
Files
Particulars
Examples
Restrictions
Literature_References
Author_and_Institution
Version
Index_Entries

Procedure

   void dafgn_c ( SpiceInt     lenout,
                  SpiceChar  * name   ) 

Abstract

 
   Return (get) the name for the current array in the current DAF. 
 

Required_Reading

 
   DAF 
 

Keywords

 
   FILES 
 

Brief_I/O

 
   Variable  I/O  Description 
   --------  ---  -------------------------------------------------- 
   lenout     I   Length of array name string.
   name       O   Name of current array. 
 

Detailed_Input

 
   lenout         is the length of the name string, including room for
                  the null terminator. For a DAF with summary
                  parameters ND and NI, the maximum length of an array 
                  name is
 
                                        (NI + 1)
                     NC  =   8 * ( ND + -------- ) (Note that this is
                                            2       integer division.)
                                            
                  Given NC, lenout should be set equal to NC+1.

Detailed_Output

 
   name        is the name for the current array (the array found by
               the latest call to daffna_c or daffpa_c).
 

Parameters

 
   None. 
 

Exceptions

 
   1)  If this routine is called when no search is in progress in the 
       the current DAF, the error SPICE(DAFNOSEARCH) is signalled. 
 
   2)  If the DAF for which the "current" array's name is to be 
       returned has actually been closed, the error will be diagnosed 
       by routines called by this routine. 
 
   3)  If no array is current in the current DAF, the error 
       SPICE(NOCURRENTARRAY) is signalled.  There is no current 
       array when a search is started by dafbfs_c or dafbbs_c, but no 
       calls to daffna_c or dafbna_c have been made yet, or whenever 
       daffna_c or daffpa_c return the value SPICEFALSE in the found 
       argument. 

   4)  The error SPICE(NULLPOINTER) is signaled if the input string
       pointer is null.

   5) The caller must pass a value indicating the length of the output
      string.  If this value is not at least 2, the error
      SPICE(STRINGTOOSHORT) is signaled.
 

Files

 
   None. 
 

Particulars

 
   The DAF search routines are:

      dafbfs_c       Begin forward search.
      daffna         Find next array.

      dafbbs_c       Begin backward search.
      daffpa_c       Find previous array.

      dafgs_c        Get summary.
      dafgn_c        Get name.
      dafgh_c        Get handle.

      dafcs_c        Continue search.

   The main function of these entry points is to allow the
   contents of any DAF to be examined on an array-by-array
   basis.

   Conceptually, the arrays in a DAF form a doubly linked list,
   which can be searched in either of two directions: forward or
   backward. It is possible to search multiple DAFs simultaneously.

   dafbfs_c (begin forward search) and daffna are used to search the
   arrays in a DAF in forward order.  In applications that search a
   single DAF at a time, the normal usage is

      dafbfs_c ( handle );
      daffna_c ( &found );

      while ( found )
      {
         dafgs_c ( sum  );
         dafgn_c ( name );
          .
          .

         daffna_c ( &found );
      }


   dafbbs_c (begin backward search) and daffpa_c are used to search the
   arrays in a DAF in backward order.  In applications that search
   a single DAF at a time, the normal usage is

      dafbbs_c ( handle );
      daffpa_c ( &found );

      while ( found )
      {
         dafgs_c ( sum  );
         dafgn_c ( name );
          .
          .

         daffpa_c ( &found );
      }


   In applications that conduct multiple searches simultaneously,
   the above usage must be modified to specify the handle of the
   file to operate on, in any case where the file may not be the
   last one specified by dafbfs_c or dafbbs_c.  The routine dafcs_c
   (DAF, continue search) is used for this purpose.  Below, we
   give an example of an interleaved search of two files specified
   by the handles handl1 and handl2.  The directions of searches
   in different DAFs are independent; here we conduct a forward
   search on one file and a backward search on the other.
   Throughout, we use dafcs to specify which file to operate on,
   before calling daffna_c, daffpa_c, dafgs_c, or dafgn_c.


      dafbfs_c ( handl1 );
      dafbbs_c ( handl2 );

      dafcs_c  ( handl1  );
      daffna_c ( &found1 );

      dafcs_c  ( handl2  );
      daffpa_c ( &found2 );

      while ( found1 || found2 )
      {
         if ( found1 )  
         {
            dafcs_c ( handl1 );
            dafgs_c ( sum    );
            dafgn_c ( name   );
             .
             .
            dafcs_c  ( &handl1 );
            daffna_c ( &found1 );
         }

         if ( found2 )  
         {
            dafcs_c ( handl2 );
            dafgs_c ( sum    );
            dafgn_c ( name   );
             .
             .
            dafcs_c  ( handl2  );
            daffpa_c ( &found2 );
         }
      }


   At any time, the latest array found (whether by daffna_c or daffpa_c)
   is regarded as the "current" array for the file in which the
   array was found.  The last DAF in which a search was started,
   executed, or continued by any of dafbfs_c, dafbbs_c, daffna_c, 
   daffpa_c or dafcs_c is regarded as the "current" DAF.  The summary 
   and name for the current array in the current DAF can be obtained
   separately, as shown above, by calls to DAFGS (get summary) and
   dafgn_c (get name).  The handle of the current DAF can also be
   obtained by calling dafgh_c (get handle).

   Once a search has been begun, it may be continued in either
   direction. That is, daffpa_c may be used to back up during a
   forward search, and daffna_c may be used to advance during a
   backward search.
 

Examples

 
   1) See Particulars. 
 

Restrictions

 
   None. 
 

Literature_References

 
   NAIF Document 167.0, "Double Precision Array Files (DAF) 
   Specification and User's Guide" 
 

Author_and_Institution

 
   N.J. Bachman    (JPL) 
   W.L. Taber      (JPL) 
   I.M. Underwood  (JPL) 
 

Version

 
   -CSPICE Version 1.0.0, 01-AUG-1999 (NJB) (WLT) (IMU)

Index_Entries

 
   get daf array name 
 
Wed Apr  5 17:54:30 2017