| daswbr_c |
|
Table of contents
Proceduredaswbr_c ( DAS, write buffered records ) void daswbr_c ( SpiceInt handle ) AbstractWrite out all buffered records of a specified DAS file. Required_ReadingDAS KeywordsASSIGNMENT DAS FILES Brief_I/OVARIABLE I/O DESCRIPTION -------- --- -------------------------------------------------- handle I Handle of DAS file. Detailed_Inputhandle is the handle of a DAS file opened for writing. Detailed_OutputNone. See -Particulars for a description of the action 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. The indicated
file will not be modified.
2) If a write operation attempted by this routine fails, an
error is signaled by a routine in the call tree of this
routine. The status of the DAS file written to is uncertain
in this case.
FilesSee the description of the argument `handle' in -Detailed_Input. ParticularsThis routine writes buffered records out to the DAS file to which they correspond. Because the DAS system buffers records that are written as well as those that are read, data supplied to the DAS add data (dasadc_c, dasadd_c, dasadi_c) and DAS update data (dasudc_c, dasudd_c, dasudi_c) routines on input has not necessarily been physically written to the DAS file specified by the caller of those routines, at the time those routines return. Before closing a DAS file that has been opened for writing, the DAS system must write out to the file any updated records present in the DAS buffers. The CSPICE routine dascls_c uses this routine to perform this function. The routines dasac_c and dasdc_c, through the use of the SPICELIB routines DASACR and DASRCR, which respectively add comment records to or delete comment records from a DAS file, use this routine to ensure that the SPICELIB routine DASRWR record buffers don't become out of sync with the file they operate upon. In addition, this routine can be used by application programs that create or update DAS files. The reason for calling this routine directly would be to provide a measure of safety when writing a very large file: if the file creation or update were interrupted, the amount of work lost due to the loss of buffered, unwritten records could be reduced. However, routines outside of CSPICE will generally not need to call this routine directly. 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) Write a DAS file by adding data to it over multiple passes.
Avoid spending time on file segregation between writes.
Each pass opens the file, adds character, double precision,
and integer data to the file, writes out buffered data by
calling daswbr_c, and closes the file without segregating the
data by calling dasllc_c.
The program also checks the file: after the final write,
the program reads the data and compares it to expected values.
Note that most user-oriented applications should segregate a
DAS file after writing it, since this greatly enhances file
reading efficiency. The technique demonstrated here may be
useful for cases in which a file will be written via many
small data additions, and in which the file is read between
write operations.
Example code begins here.
/.
Program daswbr_ex1
./
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "SpiceUsr.h"
int main( )
{
/.
Local parameters
./
#define CHRLEN 50
#define IBUFSZ 20
#define DBUFSZ 30
/.
Local variables
./
SpiceChar chrbuf [CHRLEN];
SpiceChar chrstr [CHRLEN+1];
SpiceChar xchrbf [CHRLEN+1];
SpiceDouble dpbuf [DBUFSZ];
SpiceDouble xdpbuf [DBUFSZ];
SpiceInt firstc;
SpiceInt firstd;
SpiceInt firsti;
SpiceInt handle;
SpiceInt i;
SpiceInt intbuf [IBUFSZ];
SpiceInt j;
SpiceInt lastc;
SpiceInt lastd;
SpiceInt lasti;
SpiceInt passno;
SpiceInt xintbf [IBUFSZ];
/.
Initial values
./
ConstSpiceChar * fname = "daswbr_ex1.das";
ConstSpiceChar * ftype = "ANG";
SpiceInt ncall = 1000;
SpiceInt ncomr = 10;
SpiceInt npass = 3;
/.
Open a new DAS file. We'll allocate `ncomr' records
for comments. The file type is not one of the standard
types recognized by SPICE; however it can be used to
ensure the database file is of the correct type.
We'll use the file name as the internal file name.
./
dasonw_c ( fname, ftype, fname, ncomr, &handle );
/.
Add data of character, integer, and double precision
types to the file in interleaved fashion. We'll add to
the file over `npass' "passes," in each of which we close
the file after writing.
./
for ( passno = 1; passno <= npass; passno++ )
{
if ( passno > 1 )
{
printf( "Opening file for write access...\n" );
dasopw_c ( fname, &handle );
}
for ( i = 1; i <= ncall; i++ )
{
/.
Add string data to the file.
./
strncpy( chrbuf, "Character value #", 18 );
repmi_c ( chrbuf, "#", i, CHRLEN, chrbuf );
dasadc_c ( handle, CHRLEN, 0, CHRLEN-1, CHRLEN, chrbuf );
/.
Add double precision data to the file.
./
for ( j = 1; j <= DBUFSZ; j++ )
{
dpbuf[j-1] = (SpiceDouble)( 100000000*passno + 100*i + j );
}
dasadd_c ( handle, DBUFSZ, dpbuf );
/.
Add integer data to the file.
./
for ( j = 1; j <= IBUFSZ; j++ )
{
intbuf[j-1] = 100000000*passno + 100 * i + j;
}
dasadi_c ( handle, IBUFSZ, intbuf );
}
/.
Write buffered data to the file.
./
printf( "Writing buffered data...\n" );
daswbr_c ( handle );
/.
Close the file without segregating it.
./
printf( "Closing DAS file...\n" );
dasllc_c ( handle );
}
printf( "File write is done.\n" );
/.
Check file contents.
./
dasopr_c ( fname, &handle );
/.
Read data from the file; compare to expected values.
Initialize end addresses.
./
lastc = 0;
lastd = 0;
lasti = 0;
for ( passno = 1; passno <= npass; passno++ )
{
for ( i = 1; i <= ncall; i++ )
{
/.
Check string data.
./
strncpy( xchrbf, "Character value #", 18 );
repmi_c ( xchrbf, "#", i, CHRLEN+1, xchrbf );
firstc = lastc + 1;
lastc = lastc + CHRLEN;
dasrdc_c ( handle, firstc, lastc, 0,
CHRLEN-1, CHRLEN, chrbuf );
if ( strncmp( chrbuf, xchrbf, CHRLEN ) )
{
/.
Add null-terminating character to `chrbuf' in order to
print it to the screen.
./
strncpy( chrstr, chrbuf, CHRLEN );
chrstr[CHRLEN] = '\0';
printf( "Character data mismatch:\n" );
printf( "PASS = %d\n", (int)passno );
printf( "I = %d\n", (int)i );
printf( "Expected = %s\n", xchrbf );
printf( "Actual = %s\n", chrstr );
exit( EXIT_FAILURE );
}
/.
Check double precision data.
./
for ( j = 1; j <= DBUFSZ; j++ )
{
xdpbuf[j-1] = (SpiceDouble)( 100000000*passno + 100*i + j );
}
firstd = lastd + 1;
lastd = lastd + DBUFSZ;
dasrdd_c ( handle, firstd, lastd, dpbuf );
for ( j = 0; j < DBUFSZ; j++ )
{
if ( dpbuf[j] != xdpbuf[j] )
{
printf( "Double precision data mismatch:\n" );
printf( "PASS = %d\n", (int)passno );
printf( "I = %d\n", (int)i );
printf( "J = %d\n", (int)j );
printf( "Expected = %f\n", xdpbuf[j] );
printf( "Actual = %f\n", dpbuf[j] );
exit( EXIT_FAILURE );
}
}
/.
Check integer data.
./
for ( j = 1; j <= IBUFSZ; j++ )
{
xintbf[j-1] = 100000000*passno + 100 * i + j;
}
firsti = lasti + 1;
lasti = lasti + IBUFSZ;
dasrdi_c ( handle, firsti, lasti, intbuf );
for ( j = 0; j < IBUFSZ; j++ )
{
if ( intbuf[j] != xintbf[j] )
{
printf( "Integer data mismatch:\n" );
printf( "PASS = %d\n", (int)passno );
printf( "I = %d\n", (int)i );
printf( "J = %d\n", (int)j );
printf( "Expected = %d\n", xintbf[j] );
printf( "Actual = %d\n", intbuf[j] );
exit( EXIT_FAILURE );
}
}
}
}
printf( "File check is done.\n" );
/.
Close the file.
./
dascls_c ( handle );
return ( 0 );
}
When this program was executed on a Mac/Intel/cc/64-bit
platform, the output was:
Writing buffered data...
Closing DAS file...
Opening file for write access...
Writing buffered data...
Closing DAS file...
Opening file for write access...
Writing buffered data...
Closing DAS file...
File write is done.
File check is done.
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_Entrieswrite buffered records to a DAS file |
Fri Dec 31 18:41:04 2021