| dlabns_c |
|
Table of contents
Proceduredlabns_c ( DLA, begin new segment ) void dlabns_c ( SpiceInt handle ) AbstractBegin a new segment in a DLA file. Required_ReadingDAS DLA KeywordsDAS DLA FILES Brief_I/OVARIABLE I/O DESCRIPTION -------- --- -------------------------------------------------- handle I Handle of open DLA file. Detailed_Input
handle is the integer handle associated with the DLA file to
be updated. This handle is used to identify the file
in subsequent calls to other DLA or DAS routines.
The DLA file must be open for write access. A new DLA
segment is started in the indicated file. The file
is left open, since normally data will be written to
the file following a call to this routine.
Detailed_OutputNone. See the -Particulars and -Examples header sections for a description of the actions performed by this routine. ParametersNone. Exceptions
1) If the input file handle does not refer to a DAS file that is
open for write access, an error is signaled by a routine
in the call tree of this routine.
2) If an error occurs while reading or writing to the DLA file,
the error is signaled by a routine in the call tree of
this routine.
FilesSee 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 creation of a DLA segment. DLA segments
are created by appending data to the DAS integer, double
precision, and character address spaces of a DLA file. The new
segment's descriptor is located immediately before the integer
component of the segment's data.
When a new segment is added to a DLA file, the segment is
inserted into the file's doubly linked segment list. If the new
segment is the first, the DLA file's first and last list entry
pointers are updated to point to the new segment; specifically,
these pointers point to the first integer of the new segment's
descriptor. The backward pointer of the new segment is set to
null in this case.
If the new segment is not the first, the DLA file's list end
pointer is updated to point to the new segment, and the forward
pointer of the previous segment also is updated to point to the
first integer of the new segment's descriptor. The backward
pointer of the new segment points to the first integer of the
previous segment's descriptor.
The normal sequence of operations required to create a DLA
segment is as follows:
Call dlaopn_c to create a new, empty DLA file.
For each segment to be created,
Call dlabns_c to begin a segment.
Use the DAS "add" and "update" routines to populate
the segment with data.
Call dlaens_c to end the segment.
Call dascls_c to segregate and close the DLA file.
Examples
The numerical results shown for this example 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) Create a DLA file containing one segment; the segment
contains character, double precision, and integer data.
After writing and closing the file, open the file for
read access; dump the data to standard output.
Example code begins here.
/.
Program dlabns_ex1
./
#include <stdio.h>
#include <string.h>
#include "SpiceUsr.h"
int main( )
{
/.
Local parameters
./
#define DLA "dlabns_ex1.dla"
#define LNSIZE 61
#define MAXC 5
#define MAXD 50
#define MAXI 100
/.
Local variables
./
SpiceChar buffer [2];
SpiceChar cvals [MAXC][LNSIZE];
SpiceChar cvals2 [MAXC][LNSIZE];
SpiceChar cvastr [LNSIZE+1];
SpiceChar * ifname;
SpiceDouble dvals [MAXD];
SpiceDouble dvals2 [MAXD];
SpiceDLADescr descr;
SpiceInt base;
SpiceInt handle;
SpiceInt i;
SpiceInt ivals [MAXI];
SpiceInt ivals2 [MAXI];
SpiceInt j;
SpiceInt k;
SpiceInt n;
SpiceInt ncomch;
SpiceBoolean found;
/.
Set the internal file name. Don't reserve characters in
the DAS comment area.
./
ifname = "Example DLA file for testing";
ncomch = 0;
/.
Open a new DLA file.
./
dlaopn_c ( DLA, "DLA", ifname, ncomch, &handle );
/.
Begin a new segment.
./
dlabns_c ( handle );
/.
Add character data to the segment.
./
for ( i = 0; i < MAXC; i++ )
{
for ( j = 0; j < LNSIZE; j++ )
{
/.
Remove null-terminating character added to `buffer' in order to
add it to the DLA file.
./
k = ( (j+i+1) % 10 );
snprintf(buffer, 2, "%d", k);
cvals[i][j] = buffer[0];
}
}
dasadc_c ( handle, MAXC*LNSIZE, 0, LNSIZE-1, LNSIZE, cvals );
/.
Add integer and double precision data to the segment.
./
for ( i = 0; i < MAXI; i++ )
{
ivals[i] = i+1;
}
dasadi_c ( handle, MAXI, ivals );
for ( i = 0; i < MAXD; i++ )
{
dvals[i] = (double)i+1;
}
dasadd_c ( handle, MAXD, dvals );
/.
End the segment.
./
dlaens_c ( handle );
/.
Close the file. The routine dascls_c flushes the DAS
buffers and segregates the file before closing it.
./
dascls_c ( handle );
/.
Now read the file and check the data.
./
dasopr_c ( DLA, &handle );
/.
Obtain the segment descriptor for the sole segment
in the file. We need not check the found flag
in this case because we know there is one segment
in the file.
./
dlabfs_c ( handle, &descr, &found );
/.
Fetch character data from the segment. Obtain the
base address of the character data and the
character count from the descriptor.
./
base = descr.cbase;
n = descr.csize;
dasrdc_c ( handle, base+1, base+n, 0, LNSIZE-1, LNSIZE, cvals2 );
/.
Display the character data.
./
printf( "\n" );
printf( "Character array:\n" );
for ( i = 0; i < n/LNSIZE; i++ )
{
/.
Add null-terminating character to `cvals2[i]' in order to
print it to the screen.
./
strncpy( cvastr, cvals2[i], LNSIZE );
cvastr[LNSIZE] = '\0';
printf( "%s\n", cvastr );
}
/.
Fetch and display the integer and double precision data.
./
base = descr.ibase;
n = descr.isize;
dasrdi_c ( handle, base+1, base+n, ivals2 );
printf( "\n" );
printf( "Integer array:\n" );
for ( i = 0; i < n/10; i++ )
{
for ( j = 0; j < 10; j++ )
{
printf( "%6d", ivals2[i*10+j] );
}
printf( "\n" );
}
base = descr.dbase;
n = descr.dsize;
dasrdd_c ( handle, base+1, base+n, dvals2 );
printf( "\n" );
printf( "Double precision array:\n" );
for ( i = 0; i < n/10; i++ )
{
for ( j = 0; j < 10; j++ )
{
printf( "%6.1f", dvals2[i*10+j] );
}
printf( "\n" );
}
/.
Close the file. This step is unnecessary in this
program, but is a good practice in general
because closing the file frees resources.
./
dascls_c ( handle );
return ( 0 );
}
When this program was executed on a Mac/Intel/cc/64-bit
platform, the output was:
Character array:
1234567890123456789012345678901234567890123456789012345678901
2345678901234567890123456789012345678901234567890123456789012
3456789012345678901234567890123456789012345678901234567890123
4567890123456789012345678901234567890123456789012345678901234
5678901234567890123456789012345678901234567890123456789012345
Integer array:
1 2 3 4 5 6 7 8 9 10
11 12 13 14 15 16 17 18 19 20
21 22 23 24 25 26 27 28 29 30
31 32 33 34 35 36 37 38 39 40
41 42 43 44 45 46 47 48 49 50
51 52 53 54 55 56 57 58 59 60
61 62 63 64 65 66 67 68 69 70
71 72 73 74 75 76 77 78 79 80
81 82 83 84 85 86 87 88 89 90
91 92 93 94 95 96 97 98 99 100
Double precision array:
1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 9.0 10.0
11.0 12.0 13.0 14.0 15.0 16.0 17.0 18.0 19.0 20.0
21.0 22.0 23.0 24.0 25.0 26.0 27.0 28.0 29.0 30.0
31.0 32.0 33.0 34.0 35.0 36.0 37.0 38.0 39.0 40.0
41.0 42.0 43.0 44.0 45.0 46.0 47.0 48.0 49.0 50.0
Note that after run completion, a new DLA file exists in the
output directory.
RestrictionsNone. Literature_ReferencesNone. Author_and_InstitutionJ. Diaz del Rio (ODC Space) Version-CSPICE Version 1.0.0, 14-JUN-2021 (JDR) Index_Entriesbegin new segment in DLA file |
Fri Dec 31 18:41:04 2021