| dlaopn_c |
|
Table of contents
Procedure
dlaopn_c ( DLA, open new file )
void dlaopn_c ( ConstSpiceChar * fname,
ConstSpiceChar * ftype,
ConstSpiceChar * ifname,
SpiceInt ncomch,
SpiceInt * handle )
AbstractOpen a new DLA file and set the file type. Required_ReadingDAS DLA KeywordsDAS DLA FILES Brief_I/OVARIABLE I/O DESCRIPTION -------- --- -------------------------------------------------- fname I Name of a DLA file to be opened. ftype I Mnemonic code for type of data in the DLA file. ifname I Internal file name. ncomch I Number of comment characters to allocate. handle O Handle assigned to the opened DLA file. Detailed_Input
fname is the name of a new DLA file to be created. The file
will be left opened for write access.
ftype is a code for type of data placed into a DLA file. The
non-blank part of `ftype' is used as the "file type"
portion of the ID word in the DLA file.
The first nonblank character and the three, or fewer,
characters immediately following it, giving four
characters, are used to represent the type of the data
placed in the DLA file. This is provided as a convenience
for higher level software. It is an error if this string
is blank. Also, the file type may not contain any
nonprinting characters. When written to the DLA file, the
value for the type IS case sensitive.
NAIF has reserved for its own use file types consisting
of the upper case letters (A-Z) and the digits 0-9. NAIF
recommends lower case or mixed case file types be used by
all others in order to avoid any conflicts with NAIF file
types.
ifname is the internal file name for the new file. The name may
contain as many as 60 characters. This name should
uniquely identify the file.
ncomch is the number of comment characters to allocate.
`ncomch' is used to establish the number of comment records
that will be allocated to the new DLA file. The number of
comment records allocated is the minimum required to
store the specified number of comment characters.
Allocating comment records at file creation time may
reduce the likelihood of having to expand the
comment area later.
Detailed_Output
handle is the file handle associated with the file. This handle
is used to identify the file in subsequent calls to other
DLA routines.
ParametersNone. Exceptions
1) If the input filename is blank, an error is signaled by a
routine in the call tree of this routine. No file will be
created.
2) If the specified file cannot be opened without exceeding the
maximum allowed number of open DAS files, an error is signaled
by a routine in the call tree of this routine. No file will be
created.
3) If the file cannot be opened properly, an error is signaled by
a routine in the call tree of this routine. No file will be
created.
4) If the initial records in the file cannot be written, an error
is signaled by a routine in the call tree of this routine. No
file will be created.
5) If no logical units are available, an error is signaled by a
routine in the call tree of this routine. No file will be
created.
6) If the file type is blank, an error is signaled by a routine
in the call tree of this routine. No file will be created.
7) If the file type contains nonprinting characters, decimal 0-31
and 127-255, an error is signaled by a routine in the call
tree of this routine. No file will be created.
8) If the number of comment characters allocated to be allocated,
`ncomch', is negative, the error SPICE(BADRECORDCOUNT) is
signaled by a routine in the call tree of this routine. No
file will be created.
9) If any of the `fname', `ftype' or `ifname' input string
pointers is null, the error SPICE(NULLPOINTER) is signaled.
10) If any of the `fname', `ftype' or `ifname' input strings has
zero length, the error SPICE(EMPTYSTRING) is signaled.
FilesSee argument `fname'. 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 creates a new DLA file and sets the type of the
file to the mnemonic code passed to it.
DLA files created by this routine have initialized file records.
The ID word in a DLA file record has the form
DAS/xxxx
where the characters following the slash are supplied by the
caller of this routine.
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 dlaopn_ex1
./
#include <stdio.h>
#include <string.h>
#include "SpiceUsr.h"
int main( )
{
/.
Local parameters
./
#define DLA "dlaopn_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, 19-OCT-2021 (JDR) Index_Entriesopen a new DLA file open a new DLA file with write access |
Fri Dec 31 18:41:04 2021