CSPICE_DLAFNS finds the segment following a specified segment in a
For important details concerning this module's function, please refer to
the CSPICE routine dlafns_c.
handle 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.
dladsc the descriptor of the a DLA segment in the file
associated with `handle'.
cspice_dlafns, handle, dladsc, nxtdsc, found
nxtdsc the descriptor of the next DLA segment following the
segment associated with the input argument `descr'.
`nxtdsc' is valid only if the output argument `found'
found a logical flag indicating whether the next segment was
found. `found' has the value true if the segment
was found; otherwise `found' is false.
Any numerical results shown for this example may differ between
platforms as the results depend on the SPICE kernels used as input
and the machine specific arithmetic implementation.
Open a DLA file for read access, traverse the segment
list from front to back, and display segment address
and size attributes.
PRO dlab_t, dla
SPICE_DLA_BWDIDX = 0
SPICE_DLA_FWDIDX = 1
SPICE_DLA_IBSIDX = 2
SPICE_DLA_ISZIDX = 3
SPICE_DLA_DBSIDX = 4
SPICE_DLA_DSZIDX = 5
SPICE_DLA_CBSIDX = 6
SPICE_DLA_CSZIDX = 7
;; Open the DSK file for read access.
;; We use the DAS-level interface for
;; this function.
cspice_dasopr, dla, handle
;; Begin a forward search through the
;; kernel, treating the file as a DLA.
;; In this example, it's a very short
segno = 1L
cspice_dlabfs, handle, dladsc, found
while found do begin
;; Display the contents of the current segment
print, 'Segment number = ', segno
print, ' Backward segment pointer = ', $
print, ' Forward segment pointer = ', $
print, ' Integer component base address = ', $
print, ' Integer component size = ', $
print, ' D.p. component base address = ', $
print, ' D.p. component size = ', $
print, ' Character component base address = ', $
print, ' Character component size = ', $
;; Find the next segment.
current = dladsc
segno = segno + 1
cspice_dlafns, handle, current, dladsc, found
;; Close file.
IDL> dlab_t, '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
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
This routine supports forward traversal of a DLA file's segment
list. A forward traversal may be started from any segment in
the file; it is not necessary to call cspice_dlabfs first. The role
of cspice_dlabfs is simply to return the descriptor of the first
segment in the file.
-Icy Version 1.0.0, 13-DEC-2016, ML (JPL), EDW (JPL)
find next segment in dla file