| dafopw_c |
|
Table of contents
Procedure
dafopw_c ( DAF, open for write )
void dafopw_c ( ConstSpiceChar * fname,
SpiceInt * handle )
AbstractOpen a DAF for subsequent write requests. Required_ReadingDAF KeywordsDAF FILES Brief_I/OVARIABLE I/O DESCRIPTION -------- --- -------------------------------------------------- fname I Name of DAF to be opened. handle O Handle assigned to DAF. Detailed_Inputfname is the name of a DAF to be opened with write access. Detailed_Output
handle is the file handle associated with the file. This handle
is used to identify the file in subsequent calls to other
DAF routines.
ParametersNone. Exceptions
1) If the specified file has already been opened, either by the
DAF routines or by other code, an error is signaled by a
routine in the call tree of this routine. Note that this
response is not paralleled by dafopr_c, which allows you to open
a DAF for reading even if it is already open for reading.
2) If the specified file cannot be opened without exceeding the
maximum number of files, the error SPICE(DAFFTFULL) is
signaled by a routine in the call tree of this routine.
3) If the attempt to read the file's file record fails, the error
SPICE(FILEREADFAILED) is signaled by a routine in the call
tree of this routine.
4) If the specified file is not a DAF file, an error is signaled
by a routine in the call tree of this routine.
5) If no logical units are available, an error is signaled by a
routine in the call tree of this routine.
6) If the file does not exist, an error is signaled by a routine
in the call tree of this routine.
7) If an I/O error occurs in the process of opening the file, the
error is signaled by a routine in the call tree of this
routine.
8) If the file name is blank or otherwise inappropriate, an error
is signaled by a routine in the call tree of this routine.
9) If the file was transferred improperly via FTP, an error is
signaled by a routine in the call tree of this routine.
10) If the file utilizes a non-native binary file format, an error
is signaled by a routine in the call tree of this routine.
11) If the `fname' input string pointer is null, the error
SPICE(NULLPOINTER) is signaled.
12) If the `fname' input string has zero length, the error
SPICE(EMPTYSTRING) is signaled.
FilesSee argument `fname'. ParticularsMost DAFs require only read access. If you do not need to change the contents of a file, you should open it with dafopr_c. Use dafopw_c when you need to -- change (update) one or more summaries, names, or arrays within a file; or -- add new arrays to a file. Examples
The numerical results shown for these examples may differ across
platforms. The results depend on the SPICE kernels used as
input, the compiler and supporting libraries, and the machine
specific arithmetic implementation.
1) Delete the entire comment area of a DAF file. Note that this
action should only be performed if fresh new comments are to
be placed within the DAF file.
Use the SPK kernel below as input DAF file for the program.
earthstns_itrf93_201023.bsp
Example code begins here.
/.
Program dafopw_ex1
./
#include <stdio.h>
#include "SpiceUsr.h"
int main( )
{
/.
Local parameters
./
#define KERNEL "earthstns_itrf93_201023.bsp"
#define BUFFSZ 10
#define LINLEN 1000
/.
Local variables.
./
SpiceChar buffer [BUFFSZ][LINLEN];
SpiceInt handle;
SpiceInt i;
SpiceInt n;
SpiceBoolean done;
/.
Open a DAF for write. Return a `handle' referring to the
file.
./
dafopw_c ( KERNEL, &handle );
/.
Print the first 10 lines of comments from the DAF file.
./
printf( "Comment area of input DAF file (max. 10 lines): \n" );
printf( "--------------------------------"
"------------------------------\n" );
dafec_c ( handle, BUFFSZ, LINLEN, &n, buffer, &done );
for ( i = 0; i < n; i++ )
{
printf( "%s\n", buffer[i] );
}
printf( "--------------------------------"
"------------------------------\n" );
printf( " \n" );
printf( "Deleting entire comment area...\n" );
/.
Delete all the comments from the DAF file.
./
dafdc_c ( handle );
/.
Close the DAF file and re-open it for read
access to work around the dafec_c restriction
on comments not to be modified while they are
being extracted.
./
dafcls_c ( handle );
dafopr_c ( KERNEL, &handle );
/.
Check if the comments have indeed been deleted.
./
dafec_c ( handle, BUFFSZ, LINLEN, &n, buffer, &done );
if ( done && ( n == 0 ) )
{
printf( " \n" );
printf( " Successful operation.\n" );
}
else
{
printf( " \n" );
printf( " Operation failed.\n" );
}
/.
Safely close the DAF.
./
dafcls_c ( handle );
return ( 0 );
}
When this program was executed on a Mac/Intel/cc/64-bit
platform, the output was:
Comment area of input DAF file (max. 10 lines):
--------------------------------------------------------------
SPK for DSN Station Locations
=====================================================================
Original file name: earthstns_itrf93_201023.bsp
Creation date: 2020 October 28 12:30
Created by: Nat Bachman (NAIF/JPL)
Introduction
--------------------------------------------------------------
Deleting entire comment area...
Successful operation.
2) In the following code example, dafopw_c is used to open a
file, which is then searched for arrays containing data for
a particular object. The code for the object is then changed
(perhaps to reflect some new convention).
Example code begins here.
/.
Program dafopw_ex2
./
#include <stdio.h>
#include "SpiceUsr.h"
int main()
{
/.
Local parameters.
./
#define ARCHLN 4
#define DSCSIZ 5
#define FILSIZ 256
#define KTYPLN 5
#define LINSIZ 81
#define MAXOBJ 1000
#define ND 2
#define NI 6
/.
Local variables.
./
SPICEINT_CELL ( ids, MAXOBJ );
SpiceBoolean found;
SpiceChar arch [ ARCHLN ];
SpiceChar fname [ FILSIZ ];
SpiceChar ktype [ KTYPLN ];
SpiceChar line [ LINSIZ ];
SpiceDouble dc [ ND ];
SpiceDouble sum [ DSCSIZ ];
SpiceInt handle;
SpiceInt i;
SpiceInt ic [ NI ];
SpiceInt new_code;
SpiceInt obj;
SpiceInt old_code;
/.
Get the input data.
./
prompt_c ( "Enter name of existing DAF > ", FILSIZ, fname );
prompt_c ( "Enter ID code to change > ", LINSIZ, line );
prsint_c ( line, &old_code );
prompt_c ( "Enter replacement code > ", LINSIZ, line );
prsint_c ( line, &new_code );
/.
Open the existing DAF file for write access.
./
dafopw_c ( fname, &handle );
/.
Start a forward search through the file.
./
dafbfs_c ( handle );
/.
Find the first array (segment).
./
daffna_c ( &found );
while ( found )
{
/.
Read and unpack the current DAF array summary
(aka segment descriptor) sum:
./
dafgs_c ( sum );
dafus_c ( sum, ND, NI, dc, ic );
if ( ic[0] == old_code )
{
ic[0] = new_code;
/.
Re-pack the descriptor; replace the descriptor
in the file.
./
dafps_c ( ND, NI, dc, ic, sum );
dafrs_c ( sum );
}
/.
Find the next segment.
./
daffna_c ( &found );
}
/.
Close the DAF.
./
dafcls_c ( handle );
/.
Find the set of objects in the DAF file.
./
getfat_c ( fname, ARCHLN, KTYPLN, arch, ktype );
if ( eqstr_c ( ktype, "spk" ) )
{
spkobj_c ( fname, &ids );
}
else if ( eqstr_c ( ktype, "ck" ) )
{
ckobj_c ( fname, &ids );
}
else if ( eqstr_c ( ktype, "pck" ) )
{
pckfrm_c ( fname, &ids );
}
printf( "Objects in the DAF file:\n\n" );
for ( i = 0; i < card_c( &ids ); i++ )
{
obj = SPICE_CELL_ELEM_I( &ids, i );
printf( " %d", (int)obj );
}
printf( "\n" );
return ( 0 );
}
When this program was executed on a Mac/Intel/cc/64-bit
platform, using the SPK file named de430.bsp as input
DAF file and requesting to change the Moon ID code "301"
to another (fake) ID, "-999", the output was:
Enter name of existing DAF > de430.bsp
Enter ID code to change > 301
Enter replacement code > -999
Objects in the DAF file:
-999 1 2 3 4 5 6 7 8 9 10 199 299 399
Restrictions
1) Only files of the native binary file format may be opened
with this routine.
2) Files opened using this routine must be closed with dafcls_c.
Literature_ReferencesNone. Author_and_InstitutionN.J. Bachman (JPL) J. Diaz del Rio (ODC Space) K.R. Gehringer (JPL) J.M. Lynch (JPL) J.E. McLean (JPL) W.L. Taber (JPL) F.S. Turner (JPL) I.M. Underwood (JPL) Version
-CSPICE Version 1.0.1, 25-NOV-2021 (JDR)
Edited the header to comply with NAIF standard.
Extended code example to generate outputs, provide example's solution
and replaced f2c'ed functions by CSPICE wrappers. Moved DAF required
reading from -Literature_References to -Required_Reading section.
-CSPICE Version 1.0.0, 13-OCT-2004 (NJB) (KRG) (JML) (JEM) (WLT) (FST) (IMU)
Index_Entriesopen existing DAF for write |
Fri Dec 31 18:41:03 2021