dafcs_c

Index Page dafcs_c
A B C D E F G H I J K L M N O P Q R S T U V W X
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 dafcs_c ( SpiceInt handle )
#### Abstract
       Select a DAF that already has a search in progress as the
       one to continue searching.
#### Required_Reading
       DAF
#### Keywords
       FILES
#### Brief_I/O
       Variable  I/O  Description
       --------  ---  --------------------------------------------------
       handle     I   Handle of DAF to continue searching.
#### Detailed_Input
       handle         is the handle of a DAF in which either a forward
                      or backward search has already been started by
                      dafbfs_c or dafbbs_c.  The DAF may be open for read
                      or write access.
#### Detailed_Output
       None.
#### Parameters
       None.
#### Exceptions
       1)  If the input handle is invalid, the error will be diagnosed
           by routines called by this routine.

       2)  If this routine is called when no search is in progress in the
           the current DAF, the error SPICE(DAFNOSEARCH) is signalled.
#### Files
       None.
#### Particulars
       dafcs_c supports simultaneous searching of multiple DAFs.  In
       applications that use this capability, dafcs_c should be called
       prior to each call to daffna_c, daffpa_c, dafgn_c, or dafgs_c to
       specify which DAF is to be acted upon.

       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
       None.
#### Author_and_Institution
       N.J. Bachman   (JPL)
       W.L. Taber     (JPL)
#### Version
       -CSPICE Version 1.0.0, 31-JUL-1999 (NJB) (WLT)
#### Index_Entries
       select a daf to continue searching
#### Link to routine dafcs_c source file dafcs_c.c

    Thu Apr 16 08:57:37 2009