| dasadc_c |
|
Table of contents
Procedure
dasadc_c ( DAS, add data, character )
void dasadc_c ( SpiceInt handle,
SpiceInt n,
SpiceInt bpos,
SpiceInt epos,
SpiceInt datlen,
const void * data )
AbstractAdd character data to a DAS file. Required_ReadingDAS KeywordsARRAY ASSIGNMENT DAS FILES Brief_I/O
VARIABLE I/O DESCRIPTION
-------- --- --------------------------------------------------
handle I DAS file handle.
n I Number of characters to add to file.
bpos,
epos I Begin and end positions of substrings.
datlen I Common length of the character arrays in `data'.
data I Array providing the set of substrings to be added
to the character data in the DAS file.
Detailed_Input
handle is a file handle of a DAS file opened for writing.
n is the total number of characters to add to the specified
DAS file.
bpos,
epos are the begin and end character positions that define the
substrings in each of the elements of the input array.
This routine writes the first `n' characters from the
specified set of substrings to the specified DAS file.
data is a two-dimensional character array, some portion of whose
contents are to be added to the specified DAS file.
Specifically, the first `n' characters of the substrings
data[i][bpos:epos], i = 0, ...
are appended to the character data in the file.
`data' must be declared at least as
SpiceChar data [r][epos+1]
with the dimension `r' being at least
r = int( ( n + sublen - 1 ) / sublen )
and `sublen', the length of each of the substrings in
the array to be added to the DAS file, being
sublen = epos - bpos + 1
The order of characters in the input substrings is
considered to increase from left to right within each
element of `data', and to increase with the indices of the
elements of `data'.
datlen is the common length of the character arrays in `data'.
Detailed_OutputNone. See -Particulars for a description of the effect of this routine. ParametersNone. Exceptions
1) If the input file handle is invalid, an error is signaled
by a routine in the call tree of this routine.
2) If `epos' or `bpos' are outside of the range
[ 0, datlen - 1 ]
or if epos < bpos, the error SPICE(BADSUBSTRINGBOUNDS) is
signaled by a routine in the call tree of this routine.
3) If the input count `n' is less than 1, no data will be
added to the specified DAS file.
4) If an I/O error occurs during the data addition attempted
by this routine, the error is signaled by a routine in the
call tree of this routine.
5) If `n' is greater than the number of characters in the
specified set of input substrings, the results of calling
this routine are unpredictable. This routine cannot
detect this error.
6) If the `data' input string pointer is null, the error
SPICE(NULLPOINTER) is signaled.
7) If the `data' input string has length less than one character,
the error SPICE(NODATA) is signaled.
FilesSee the description of the argument `handle' in -Detailed_Input. Particulars
DAS is a low-level format meant to store and transmit data. As
such, character data in DAS files are not interpreted by SPICELIB
DAS input or output routines. There are no limits on which
character values may be placed in the virtual character array of a
DAS file.
This routine adds character data to a DAS file by "appending" them
after any character data already in the file. The sense in which
the data are "appended" is that the data will occupy a range of
logical addresses for character data that immediately follow the
last logical address of a character that is occupied at the time
this routine is called. The diagram below illustrates this
addition:
+-------------------------+
| (already in use) | Character logical address 1
+-------------------------+
.
.
.
+-------------------------+ last character logical address
| (already in use) | in use before call to dasadc_c
+-------------------------+
| data[0][bpos] | First added character
+-------------------------+
| data[0][bpos+1] |
+-------------------------+
.
.
.
+-------------------------+
| data[0][epos] |
+-------------------------+
| data[1][bpos] |
+-------------------------+
.
.
.
+-------------------------+
| data[r-1][c] | n'th added character---here `r' is
+-------------------------+
(SpiceInt)( (n+l-1)/l )
where l = epos - bpos + 1, and
`c' is
bpos + ( n - (r-1)*l ) - 1
The logical organization of the characters in the DAS file is
independent of the order of addition to the file or physical
location of any data of integer or double precision type.
The actual physical write operations that add the input array
`data' to the indicated DAS file may not take place before this
routine returns, since the DAS system buffers data that are
written as well as data that are read. In any case, the data
will be flushed to the file at the time the file is closed, if
not earlier. A physical write of all buffered records can be
forced by calling the CSPICE routine daswbr_c (DAS, write
buffered records).
In order to update character logical addresses that already
contain data, the CSPICE routine dasudc_c (DAS, update data,
character) should be used.
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) The following example demonstrates the capabilities of the
DAS character data routines. The reader should notice that
in these interfaces, the character data are treated not as
strings (or arrays of strings) but as a stream of single
characters: DAS character data are not limited to
human-readable text. For example, one can store images or
DEM data as DAS character data.
The example shows how to add a variable amount of character
data to a new DAS file, how to update some of the character
logical addresses within that file, and how to read that
data out to a different array.
Example code begins here.
/.
Program dasadc_ex1
./
#include <stdio.h>
#include <string.h>
#include "SpiceUsr.h"
int main( )
{
/.
Local parameters.
./
#define FNAME "dasadc_ex1.das"
#define TYPE "TEST"
/.
Local variables.
./
SpiceChar cdatin [3][22];
SpiceInt handle;
SpiceInt i;
SpiceChar cdastr [31];
SpiceChar cdatou [10][30] = {
"..............................",
"..............................",
"..............................",
"..............................",
"..............................",
"..............................",
"..............................",
"..............................",
" 1 2 3",
"123456789012345678901234567890" };
/.
Open a new DAS file. Use the file name as the internal
file name, and reserve no records for comments.
./
dasonw_c ( FNAME, TYPE, FNAME, 0, &handle );
/.
Set the input data. Note that these data will be
considered as a binary data stream: DAS character data
are not limited to human-readable text. For example,
one can store images or DEM data as DAS character data.
./
strncpy( cdatin[0], "--F-345678901234567890", 22 );
strncpy( cdatin[1], "--S-345678901234567890", 22 );
strncpy( cdatin[2], "--T-IRDxxxxxxxxxxxxxxx", 22 );
/.
Add the last 20 characters of the first two elements
of `cdatin', and the 3rd character from the third one.
./
dasadc_c ( handle, 41, 2, 21, 22, cdatin );
/.
Update the 10th, 20th and 30th character in the DAS
file with a vertical bar.
./
for ( i = 1; i < 4; i++ )
{
dasudc_c ( handle, i*10, i*10, 0, 0, 1, "|" );
}
/.
Close the file.
./
dascls_c ( handle );
/.
Now verify the addition of data by opening the
file for read access and retrieving the data.
./
dasopr_c ( FNAME, &handle );
/.
Read the 41 characters that we stored on the DAS
file. Update the data on the `cdatou' array, placing
6 characters on each element, starting from the
10th position.
./
dasrdc_c ( handle, 1, 41, 9, 14, 30, cdatou );
/.
Dump the data to the screen. Note that the last
three lines should remain unmodified, and that
only 5 characters will be written on the 7th line.
./
printf( "\n" );
printf( "Data from \"%s\":\n", FNAME );
printf( "\n" );
for ( i = 0; i < 10; i++ )
{
/.
Add null-terminating character to `cdatou[i]' in order to
print it to the screen.
./
strncpy( cdastr, cdatou[i], 30 );
cdastr[30] = '\0';
printf( "%s\n", cdastr );
}
/.
Close the file.
./
dascls_c ( handle );
return ( 0 );
}
When this program was executed on a Mac/Intel/cc/64-bit
platform, the output was:
Data from "dasadc_ex1.das":
.........F-3456...............
.........789|12...............
.........345678...............
.........9|S-34...............
.........56789|...............
.........123456...............
.........7890T................
..............................
1 2 3
123456789012345678901234567890
Note that after run completion, a new DAS file exists in the
output directory.
RestrictionsNone. Literature_ReferencesNone. Author_and_InstitutionJ. Diaz del Rio (ODC Space) Version-CSPICE Version 1.0.0, 19-MAY-2021 (JDR) Index_Entriesadd character data to a DAS file |
Fri Dec 31 18:41:03 2021