| dasudc_c |
|
Table of contents
Procedure
dasudc_c ( DAS, update data, character )
void dasudc_c ( SpiceInt handle,
SpiceInt first,
SpiceInt last,
SpiceInt bpos,
SpiceInt epos,
SpiceInt datlen,
const void * data )
AbstractUpdate character data in a specified range of DAS logical addresses with substrings of a character array. Required_ReadingDAS KeywordsASSIGNMENT DAS FILES Brief_I/OVARIABLE I/O DESCRIPTION -------- --- -------------------------------------------------- handle I DAS file handle. first, last I Range of DAS character logical addresses. bpos, epos I Begin and end positions of substrings. datlen I Common length of the character arrays in `data'. data I Data having addresses `first' through `last'. Detailed_Input
handle is a file handle of a DAS file opened for writing.
first,
last are the first and last of a range of DAS logical
addresses of characters. These addresses satisfy
the inequality
1 <= first <= last <= lastc
where `lastc' is the last character logical address
in use in the DAS file designated by `handle'.
bpos,
epos are the begin and end character positions that define the
substrings in each of the elements of the input array
that are to replace the data in the range of DAS
character addresses given by `first' and `last'.
data is a two-dimensional character array. The contents of the
specified substrings of the elements of the array `data' will be
written to the indicated DAS file in order: data[0][bpos] will
be written to character logical address `first'; data[0][bpos+1]
will be written to the character logical address first+1, and so
on; in this ordering scheme, character [bpos] of data[i] is the
successor of character [epos] of data[i-1].
`data' must be declared at least as
SpiceChar data [r][epos+1]
with the dimension `r' being at least
r = int( ( last - first + sublen ) / sublen )
and `sublen', the length of each of the substrings in
the array to be written to the DAS file, being
sublen = epos - bpos + 1
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) Only logical addresses that already contain data may be
updated: if either `first' or `last' are outside the range
[ 1, lastc ]
where `lastc' is the last character logical address that currently
contains data in the indicated DAS file, the error
SPICE(INVALIDADDRESS) is signaled by a routine in the call tree of
this routine. The DAS file will not be modified.
3) If `epos' or `bpos' are outside of the range
[ 0, datlen-1 ]
the error SPICE(INVALIDINDEX) is signaled by a routine in the call
tree of this routine.
4) If `bpos' is greater than `epos', the error SPICE(INDICESOUTOFORDER)
is signaled by a routine in the call tree of this routine.
5) If first > last but both addresses are valid, this routine
will not modify the indicated DAS file. No error will be
signaled.
6) If an I/O error occurs during the data update attempted
by this routine, the error is signaled by a routine in the
call tree of this routine. `first' and `last' will not be
modified.
7) If the `data' input string pointer is null, the error
SPICE(NULLPOINTER) is signaled.
8) 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. ParticularsDAS is a low-level format meant to store and transmit data. As such, character data in DAS files are not interpreted by CSPICE 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 replaces the character data in the specified range of logical addresses within a DAS file with the contents of the specified substrings of the input array `data'. The actual physical write operations that update the indicated DAS file with the contents of the input array `data' 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 append character data to a DAS file, filling in a range of character logical addresses that starts immediately after the last character logical address currently in use, the CSPICE routine dasadc_c (DAS add 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 dasudc_ex1
./
#include <stdio.h>
#include <string.h>
#include "SpiceUsr.h"
int main( )
{
/.
Local parameters.
./
#define FNAME "dasudc_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 "dasudc_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_Entriesupdate a range of DAS logical addresses using substrings write substrings to a range of DAS logical addresses |
Fri Dec 31 18:41:04 2021