void dafus_c ( ConstSpiceDouble sum [],
SpiceInt nd,
SpiceInt ni,
SpiceDouble dc [],
SpiceInt ic [] )
Unpack an array summary into its double precision and integer
components.
DAF
CONVERSION
FILES
Variable I/O Description
-------- --- --------------------------------------------------
sum I Array summary.
nd I Number of double precision components.
ni I Number of integer components.
dc O Double precision components.
ic O Integer components.
sum is an array summary. This identifies the contents and
location of a single array within a DAF.
nd is the number of double precision components in
the summary.
ni is the number of integer components in the summary.
dc are the double precision components of the summary.
ic are the integer components of the summary.
None.
Error free.
1) If nd is zero or negative, no double precision components
are returned.
2) If ni is zero or negative, no integer components are returned.
3) If the total size of the summary is greater than 125 double
precision words, some components may not be returned.
None.
The components of array summaries are packed into double
precision arrays for reasons outlined in [1]. Two routines,
DAFPS (pack summary) and dafus_c (unpack summary) are provided
for packing and unpacking summaries.
The total size of the summary is
(ni - 1)
nd + -------- + 1
2
double precision words (where nd, ni are nonnegative).
Example (1):
In the following code fragment, dafopr_c is used to open a file,
which is then searched for DAFs containing data for a particular
object. dafus_c is used to unpack the summaries so the applicability
of the segments can be determined.
#include "SpiceUsr.h"
.
.
.
dafopr_c ( fname, &handle );
dafbfs_c ( handle );
daffna_c ( &found );
while ( found )
{
dafgs_c ( sum );
dafus_c ( sum, ND, NI, dc, ic );
if ( ic[0] == target_object )
{
.
.
.
}
daffna_c ( &found );
}
Example (2):
Use a simple routine to output the double precision and integer
values stored in an SPK's segments descriptors. This function
opens a DAF for read, performs a forwards search for the DAF
arrays, prints segments description for each array found, then
closes the DAF.
#include <stdio.h>
#include "SpiceUsr.h"
int main()
{
/.
Local constants
./
/.
Define the summary parameters appropriate
for an SPK file.
./
#define ND 2
#define NI 6
#define MAXSUM 125
SpiceInt ic [ NI ];
SpiceInt handle;
SpiceDouble dc [ ND ];
SpiceDouble sum [ MAXSUM ];
SpiceChar * kernel = "de421.bsp";
SpiceBoolean found;
/.
Open a DAF for read. Return a handle referring to the file.
./
dafopr_c ( kernel, &handle );
/.
Begin a forward search on the file.
./
dafbfs_c ( handle );
/.
Search until a DAF array is found.
./
daffna_c ( &found );
/.
Loop while the search finds subsequent DAF arrays.
./
while ( found )
{
dafgs_c ( sum );
dafus_c ( sum, ND, NI, dc, ic );
printf( " Doubles: %f %f \n", dc[0], dc[1] );
printf( "Integers: %ld %ld %ld %ld %ld %ld\n\n",
ic[0], ic[1], ic[2], ic[3], ic[4], ic[5] );
/.
Check for another segment.
./
daffna_c ( &found );
}
/.
Safely close the DAF.
./
dafcls_c ( handle );
return ( 0 );
}
The program outputs:
Doubles: -3169195200.0000000 1696852800.0000000
Integers: 1 0 1 2 641 310404
Doubles: -3169195200.0000000 1696852800.0000000
Integers: 2 0 1 2 310405 423048
Doubles: -3169195200.0000000 1696852800.0000000
Integers: 3 0 1 2 423049 567372
Doubles: -3169195200.0000000 1696852800.0000000
Integers: 4 0 1 2 567373 628976
Doubles: -3169195200.0000000 1696852800.0000000
Integers: 5 0 1 2 628977 674740
Doubles: -3169195200.0000000 1696852800.0000000
Integers: 6 0 1 2 674741 715224
Doubles: -3169195200.0000000 1696852800.0000000
Integers: 7 0 1 2 715225 750428
Doubles: -3169195200.0000000 1696852800.0000000
Integers: 8 0 1 2 750429 785632
Doubles: -3169195200.0000000 1696852800.0000000
Integers: 9 0 1 2 785633 820836
Doubles: -3169195200.0000000 1696852800.0000000
Integers: 10 0 1 2 820837 944040
Doubles: -3169195200.0000000 1696852800.0000000
Integers: 301 3 1 2 944041 1521324
Doubles: -3169195200.0000000 1696852800.0000000
Integers: 399 3 1 2 1521325 2098608
Doubles: -3169195200.0000000 1696852800.0000000
Integers: 199 1 1 2 2098609 2098620
Doubles: -3169195200.0000000 1696852800.0000000
Integers: 299 2 1 2 2098621 2098632
Doubles: -3169195200.0000000 1696852800.0000000
Integers: 499 4 1 2 2098633 2098644
Note, the final entries in the integer array contains the segment
start/end indexes. The output indicates the search proceeded
from the start of the file (low value index) towards the end
(high value index).
None.
None.
N.J. Bachman (JPL)
I.M. Underwood (JPL)
-CSPICE Version 1.0.1, 10-OCT-2012 (EDW)
Added a functional code example to the Examples section.
Removed the obsolete Reference citation to "NAIF
Document 167.0."
-CSPICE Version 1.0.0, 01-AUG-1999 (NJB), (IMU)
unpack daf summary
Link to routine dafus_c source file dafus_c.c
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