| ekaclc_c |
|
Table of contents
Procedure
ekaclc_c ( EK, add character column to segment )
void ekaclc_c ( SpiceInt handle,
SpiceInt segno,
ConstSpiceChar * column,
SpiceInt vallen,
const void * cvals,
ConstSpiceInt * entszs,
ConstSpiceBoolean * nlflgs,
ConstSpiceInt * rcptrs,
SpiceInt * wkindx )
AbstractAdd an entire character column to an EK segment. Required_ReadingEK KeywordsEK Brief_I/OVARIABLE I/O DESCRIPTION -------- --- -------------------------------------------------- handle I EK file handle. segno I Number of segment to add column to. column I Column name. vallen I Length of character values. cvals I Character values to add to column. entszs I Array of sizes of column entries. nlflgs I Array of null flags for column entries. rcptrs I Record pointers for segment. wkindx I-O Work space for column index. Detailed_Input
handle is the handle of an EK file that is open for writing.
A "begin segment for fast write" operation must
have already been performed for the designated
segment.
segno is the number of the segment to which data is to be
added. Segments are numbered from 0 to nseg-1, where
nseg is the count of segments in the file.
column is the name of the column to be added. All of
the data for the named column will be added in
one shot.
vallen is the length of the strings in the cvals array.
The array should be declared with dimensions
[nrows][vallen]
where nrows is the number of rows in the column.
cvals is an array containing the entire set of column
entries for the specified column. The entries
are listed in row-order: the column entry for the
first row of the segment is first, followed by the
column entry for the second row, and so on. The
number of column entries must match the declared
number of rows in the segment. For columns having
fixed-size entries, a null entry must be allocated
the same amount of space occupied by a non-null
entry in the array cvals. For columns having
variable-size entries, null entries do not require
any space in the cvals* array, but in any case must
have their allocated space described correctly by
the corresponding element of the entszs array
(described below).
entszs is an array containing sizes of column entries.
The Ith element of entszs gives the size of the
Ith column entry. entszs is used only for columns
having variable-size entries. For such columns,
the dimension of entszs must be at least nrows.
The size of null entries should be set to zero.
For columns having fixed-size entries, the
dimension of this array may be any positive value.
nlflgs is an array of logical flags indicating whether
the corresponding entries are null. If the Ith
element of nlflgs is SPICEFALSE, the Ith column entry
defined by cvals and entszs is added to the
current segment in the specified kernel file.
If the Ith element of nlfgls is SPICETRUE, the
contents of the Ith column entry are undefined.
nlflgs is used only for columns that allow null
values; it's ignored for other columns.
rcptrs is an array of record pointers for the input
segment. This array is obtained as an output
from ekifld_c, the routine called to initiate a
fast write.
wkindx is a work space array used for building a column
index. If the column is indexed, the dimension of
wkindx_c must be at nrows, where nrows is the number
of rows in the column. If the column is not
indexed, this work space is not used, so the
dimension may be any positive value.
Detailed_OutputNone. See -Particulars for a description of the effect of this routine. ParametersNone. Exceptions
1) If `handle' is invalid, an error is signaled by a routine in the
call tree of this routine.
2) If `column' is not the name of a declared column, an error is
signaled by a routine in the call tree of this routine.
3) If `column' specifies a column of whose data type is not
integer, the error SPICE(WRONGDATATYPE) is signaled by a
routine in the call tree of this routine.
4) If the specified column already contains ANY entries, an error
is signaled by a routine in the call tree of this routine.
5) If an I/O error occurs while reading or writing the indicated
file, the error is signaled by a routine in the call tree of
this routine.
6) If the `column' input string pointer is null, the error
SPICE(NULLPOINTER) is signaled.
7) If the `column' input string has zero length, the error
SPICE(EMPTYSTRING) is signaled.
8) If the `cvals' input array pointer is null, the error
SPICE(NULLPOINTER) is signaled.
9) If the `cvals' input array strings have length less than two
characters, the error SPICE(STRINGTOOSHORT) is signaled.
10) If memory cannot be allocated to create the temporary
variables required for the execution of the underlying Fortran
routine, the error SPICE(MALLOCFAILED) is signaled.
FilesSee the EK Required Reading for a discussion of the EK file format. ParticularsThis routine operates by side effects: it modifies the named EK file by adding data to the specified column. This routine writes the entire contents of the specified column in one shot. This routine creates columns much more efficiently than can be done by sequential calls to ekacec_c, but has the drawback that the caller must use more memory for the routine's inputs. This routine cannot be used to add data to a partially completed column. 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) Suppose we want to create an Sequence Component E-kernel
named "ekaclc_ex1.bdb" which contains records of orders for
data products. The E-kernel has a table called DATAORDERS
that consists of the set of columns listed below:
DATAORDERS
Column Name Data Type
----------- ---------
ORDER_ID INTEGER
CUSTOMER_ID INTEGER
LAST_NAME CHARACTER*(*)
FIRST_NAME CHARACTER*(*)
ORDER_DATE TIME
COST DOUBLE PRECISION
The order database also has a table of items that have been
ordered. The columns of this table are shown below:
DATAITEMS
Column Name Data Type
----------- ---------
ITEM_ID INTEGER
ORDER_ID INTEGER
ITEM_NAME CHARACTER*(*)
DESCRIPTION CHARACTER*(*)
PRICE DOUBLE PRECISION
The file "ekaclc_ex1.bdb" will contain two segments, the first
containing the DATAORDERS table and the second containing the
DATAITEMS table.
This example demonstrates how to open a new EK file and create
the first of the segments described above.
Use the LSK kernel below to load the leap seconds and time
constants required for the conversions.
naif0012.tls
Example code begins here.
/.
Program ekaclc_ex1
./
#include <stdio.h>
#include <string.h>
#include "SpiceUsr.h"
int main()
{
/.
Constants
./
#define CNMLEN ( SPICE_EK_CNAMSZ + 1 )
#define DECLEN 201
#define EKNAME "ekaclc_ex1.bdb"
#define FNMLEN 50
#define IFNAME "Test EK/Created 03-JUL-2018"
#define LNMLEN 50
#define LSK "naif0012.tls"
#define NCOLS 6
#define NRESVC 0
#define NROWS 9
#define TABLE "DATAORDERS"
#define TNMLEN SPICE_EK_TNAMSZ
#define UTCLEN 30
/.
Local variables
./
SpiceBoolean nlflgs [ NROWS ];
SpiceChar cdecls [ NCOLS ] [ DECLEN ];
SpiceChar cnames [ NCOLS ] [ CNMLEN ];
SpiceChar fnames [ NROWS ] [ FNMLEN ];
SpiceChar lnames [ NROWS ] [ LNMLEN ];
SpiceChar dateStr[ UTCLEN ];
SpiceDouble costs [ NROWS ];
SpiceDouble ets [ NROWS ];
SpiceInt cstids [ NROWS ];
SpiceInt ordids [ NROWS ];
SpiceInt handle;
SpiceInt i;
SpiceInt rcptrs [ NROWS ];
SpiceInt segno;
SpiceInt sizes [ NROWS ];
SpiceInt wkindx [ NROWS ];
/.
Load a leapseconds kernel for UTC/ET conversion.
./
furnsh_c ( LSK );
/.
Open a new EK file. For simplicity, we will not
reserve any space for the comment area, so the
number of reserved comment characters is zero.
The constant IFNAME is the internal file name.
./
ekopn_c ( EKNAME, IFNAME, NRESVC, &handle );
/.
Set up the table and column names and declarations
for the DATAORDERS segment. We'll index all of
the columns. All columns are scalar, so we omit
the size declaration. Only the COST column may take
null values.
./
strcpy ( cnames[0], "ORDER_ID" );
strcpy ( cdecls[0], "DATATYPE = INTEGER, INDEXED = TRUE" );
strcpy ( cnames[1], "CUSTOMER_ID" );
strcpy ( cdecls[1], "DATATYPE = INTEGER, INDEXED = TRUE" );
strcpy ( cnames[2], "LAST_NAME" );
strcpy ( cdecls[2], "DATATYPE = CHARACTER*(*),"
"INDEXED = TRUE" );
strcpy ( cnames[3], "FIRST_NAME" );
strcpy ( cdecls[3], "DATATYPE = CHARACTER*(*),"
"INDEXED = TRUE" );
strcpy ( cnames[4], "ORDER_DATE" );
strcpy ( cdecls[4], "DATATYPE = TIME, INDEXED = TRUE" );
strcpy ( cnames[5], "COST" );
strcpy ( cdecls[5], "DATATYPE = DOUBLE PRECISION,"
"INDEXED = TRUE,"
"NULLS_OK = TRUE" );
/.
Start the segment. We presume the number of rows
of data is known in advance.
./
ekifld_c ( handle, TABLE, NCOLS, NROWS, CNMLEN,
cnames, DECLEN, cdecls, &segno, rcptrs );
/.
At this point, arrays containing data for the
segment's columns may be filled in. The names
of the data arrays are shown below.
Column Data array
"ORDER_ID" ordids
"CUSTOMER_ID" cstids
"LAST_NAME" lnames
"FIRST_NAME" fnames
"ORDER_DATE" ets
"COST" costs
The null flags array indicates which entries are null.
It is ignored for columns that don't allow null
values. In this case, only the COST column allows
nulls.
Fill in data arrays and null flag arrays here. This code
section would normally be replaced by calls to user functions
returning column values.
./
for ( i = 0; i < NROWS; i++ )
{
ordids[i] = i;
cstids[i] = i*100;
costs [i] = (SpiceDouble) 100*i;
sprintf ( fnames[i], "Order %d Customer first name", i );
sprintf ( lnames[i], "Order %d Customer last name", i );
sprintf ( dateStr, "1998 Mar %d", i );
utc2et_c ( dateStr, ets+i );
nlflgs[i] = SPICEFALSE;
}
nlflgs[1] = SPICETRUE;
/.
The sizes array shown below is ignored for scalar
and fixed-size array columns, so we need not
initialize it. For variable-size arrays, the
Ith element of the sizes array must contain the size
of the Ith column entry in the column being written.
Normally, the sizes array would be reset for each
variable-size column.
Add the columns of data to the segment. All of the
data for each column is written in one shot.
./
ekacli_c ( handle, segno, "order_id", ordids,
sizes, nlflgs, rcptrs, wkindx );
ekacli_c ( handle, segno, "customer_id", cstids,
sizes, nlflgs, rcptrs, wkindx );
ekaclc_c ( handle, segno, "last_name", LNMLEN,
lnames, sizes, nlflgs, rcptrs, wkindx );
ekaclc_c ( handle, segno, "first_name", FNMLEN,
fnames, sizes, nlflgs, rcptrs, wkindx );
ekacld_c ( handle, segno, "order_date", ets,
sizes, nlflgs, rcptrs, wkindx );
ekacld_c ( handle, segno, "cost", costs,
sizes, nlflgs, rcptrs, wkindx );
/.
Complete the segment. The `rcptrs' array is that
returned by ekifld_c.
./
ekffld_c ( handle, segno, rcptrs );
/.
At this point, the second segment could be
created by an analogous process. In fact, the
second segment could be created at any time; it is
not necessary to populate the first segment with
data before starting the second segment.
The file must be closed by a call to ekcls_c.
./
ekcls_c ( handle );
return ( 0 );
}
When this program is executed, no output is presented on
screen. After run completion, a new EK file exists in the
output directory.
Restrictions
1) Only one segment can be created at a time using the fast
write routines.
2) No other EK operation may interrupt a fast write. For
example, it is not valid to issue a query while a fast write
is in progress.
Literature_ReferencesNone. Author_and_InstitutionN.J. Bachman (JPL) J. Diaz del Rio (ODC Space) E.D. Wright (JPL) Version
-CSPICE Version 1.2.3, 10-AUG-2021 (JDR)
Edited the header to comply with NAIF standard.
Updated code example to include the string.h file, and to
update EK parameter names to "SPICE_EK_CNAMSZ" and
"SPICE_EK_TNAMSZ".
Added entry #10 to -Exceptions section.
-CSPICE Version 1.2.2, 14-AUG-2006 (EDW)
Replace mention of ldpool_c with furnsh_c.
-CSPICE Version 1.2.1, 09-JAN-2002 (NJB)
Documentation change: instances of the phrase "fast load"
were replaced with "fast write."
Const-qualified input array cvals.
-CSPICE Version 1.1.0, 12-JUL-1998 (NJB)
Bug fix: now counts elements rather than rows for vector-valued
columns.
Bug fix: now uses dynamically allocated array of type logical
to interface with underlying f2c'd function ekaclc_.
Now maps segno from C to Fortran range.
Added "undef" of masking macro. Changed input pointer types
to pointers to const objects.
Replaced eksdsc_ call with ekssum_c call. This removes unsightly
references to segment descriptor alignments.
Fixed some chkout_c calls which referenced ekifld_c.
-CSPICE Version 1.0.0, 25-FEB-1999 (NJB)
Based on SPICELIB Version 1.0.0, 08-NOV-1995 (NJB)
Index_Entrieswrite entire character column to EK segment |
Fri Dec 31 18:41:05 2021