Index Page dlabfs_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 dlabfs_c ( SpiceInt          handle,
                       SpiceDLADescr   * descr,
                       SpiceBoolean    * found  )

#### Abstract

       Begin a forward segment search in a DLA file.

#### Required_Reading

       DAS
       DLA

#### Keywords

       DAS
       DLA
       FILES

#### Brief_I/O

       Variable  I/O  Description
       --------  ---  --------------------------------------------------
       handle     I   Handle of open DLA file.
       descr      O   Descriptor of first segment in DLA file.
       found      O   Flag indicating whether a segment was found.

#### Detailed_Input

       handle      is the DAS integer handle associated with the file to be
                   searched. This handle is used to identify the file in
                   subsequent calls to other DLA or DAS routines.

#### Detailed_Output

       descr       is the descriptor of the first DLA segment in the file
                   associated with `handle'. `descr' is valid only if the
                   output argument `found' is SPICETRUE.

       found       is a logical flag indicating whether a segment was
                   found.  `found' has the value SPICETRUE if a segment was
                   found; otherwise `found' is SPICEFALSE.

#### Parameters

       None.

#### Exceptions

       1) If the input file handle is invalid, the error will be
          diagnosed by routines in the call tree of this routine.

       2) If an error occurs while reading the DLA file, the error
          will be diagnosed by routines in the call tree of this
          routine.

#### Files

       See description of input argument `handle'.

#### Particulars

       DLA files are built using the DAS low-level format; DLA files are
       a specialized type of DAS file in which data are organized as a
       doubly linked list of segments.  Each segment's data belong to
       contiguous components of character, double precision, and integer
       type.

       This routine supports forward traversal of a DLA file's segment
       list.  Note that it is not necessary to call this routine to
       conduct a forward traversal; all that is necessary is to have
       access to the first descriptor in the file, which this routine
       provides.

#### Examples

       1)  Open a DLA file for read access, traverse the segment
           list from front to back, and display segment address
           and size attributes.

              #include "SpiceUsr.h"
              #include "SpiceDLA.h"
              #include <stdio.h>

              int main()
              {
                 /.
                 Local parameters
                 ./
                 #define FILSIZ           256

                 /.
                 Local variables
                 ./
                 SpiceBoolean            found;
                 SpiceChar               fname  [ FILSIZ ];
                 SpiceDLADescr           current;
                 SpiceDLADescr           descr;
                 SpiceInt                handle;
                 SpiceInt                segno;

                 /.
                 Prompt for the name of the file to search.
                 ./
                 prompt_c ( "Name of DLA file > ", FILSIZ, fname );

                 /.
                 Open the DLA file for read access.  Since DLA
                 files use the DAS architecture, we can use DAS
                 routines to open and close the file.
                 ./
                 dasopr_c ( fname, &handle );

                 /.
                 Begin a forward search.  Let `descr' contain
                 the descriptor of the first segment.
                 ./
                 segno = 0;

                 dlabfs_c ( handle, &descr, &found );

                 while ( found )
                 {
                    /.
                    Display the contents of the current segment
                    descriptor.
                    ./

                    ++segno;

                    printf ( "\n"
                             "\n"
                             "Segment number = %d\n"
                             "\n"
                             "   Backward segment pointer         = %d\n"
                             "   Forward segment pointer          = %d\n"
                             "   Integer component base address   = %d\n"
                             "   Integer component size           = %d\n"
                             "   D.p. component base address      = %d\n"
                             "   D.p. component size              = %d\n"
                             "   Character component base address = %d\n"
                             "   Character component size         = %d\n",
                             (int)(segno),
                             (int)(descr.bwdptr),
                             (int)(descr.fwdptr),
                             (int)(descr.ibase),
                             (int)(descr.isize),
                             (int)(descr.dbase),
                             (int)(descr.dsize),
                             (int)(descr.cbase),
                             (int)(descr.csize)                                  );

                    /.
                    Find the next segment.
                    ./
                    current = descr;

                    dlafns_c ( handle, &current, &descr, &found );
                 }

                 /.
                 Close the file using the DAS close routine.
                 ./
                 dascls_c ( handle );

                 return ( 0 );
              }

       The program outputs:

          Name of DLA file > /kernels/gen/dsk/phobos_3_3.bds

          Segment number = 1

             Backward segment pointer         = -1
             Forward segment pointer          = -1
             Integer component base address   = 11
             Integer component size           = 3311271
             D.p. component base address      = 0
             D.p. component size              = 494554
             Character component base address = 0
             Character component size         = 0

#### Restrictions

       None.

#### Literature_References

       None.

#### Author_and_Institution

       N.J. Bachman    (JPL)

#### Version

       -CSPICE Version 1.0.0, 09-JAN-2017 (EDW) (NJB)

           Edit to example program to use "%d" with explicit casts
           to int for printing SpiceInts with printf.

         23-JAN-2013 (NJB)

           Deleted third exception description from the Exceptions
           header section.

         17-NOV-2009 (NJB)

           First release.

#### Index_Entries

       begin forward search in dla file

#### Link to routine dlabfs_c source file dlabfs_c.c

    Wed Apr  5 17:54:31 2017