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ekffld_c

Table of contents
Procedure
Abstract
Required_Reading
Keywords
Brief_I/O
Detailed_Input
Detailed_Output
Parameters
Exceptions
Files
Particulars
Examples
Restrictions
Literature_References
Author_and_Institution
Version
Index_Entries

Procedure

   ekffld_c ( EK, finish fast write ) 

   void ekffld_c ( SpiceInt     handle,
                   SpiceInt     segno,
                   SpiceInt   * rcptrs )

Abstract

   Complete a fast write operation on a new E-kernel segment.

Required_Reading

   EK

Keywords

   EK


Brief_I/O

   VARIABLE  I/O  DESCRIPTION
   --------  ---  --------------------------------------------------
   handle     I   File handle.
   segno      I   Segment number.
   rcptrs     I   Record pointers.

Detailed_Input

   handle      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.

   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.

Detailed_Output

   None.

   See the -Particulars section for a description of the
   effects of this routine.

Parameters

   None.

Exceptions

   1)  If `handle' is invalid, an error is signaled by a routine in the
       call tree of this routine.

   2)  If an attempt is made to finish a segment other than the one
       last initialized by ekifld_c, an error is signaled by a routine
       in the call tree of this routine.

   3)  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.

Files

   See the EK Required Reading for a discussion of the EK file
   format.

Particulars

   This routine completes an EK segment after the data has been
   written via the fast column writer routines. The segment must
   have been created by a call to ekifld_c. The fast column
   writer routines are:

      ekaclc_c {EK, add column, character}
      ekacld_c {EK, add column, double precision}
      ekacli_c {EK, add column, integer}

   The segment is not guaranteed to be readable until all columns
   have been added. After the columns have been added, the segment
   may be extended by inserting more records and filling in those
   records using the ekaceX_c routines.

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 "ekffld_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 "ekffld_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 ekffld_ex1
      ./
      #include <stdio.h>
      #include <string.h>
      #include "SpiceUsr.h"

      int main()
      {
         /.
         Constants
         ./
         #define  CNMLEN      ( SPICE_EK_CNAMSZ + 1 )
         #define  DECLEN        201
         #define  EKNAME        "ekffld_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_References

   None.

Author_and_Institution

   N.J. Bachman        (JPL)
   J. Diaz del Rio     (ODC Space)
   E.D. Wright         (JPL)

Version

   -CSPICE Version 2.1.0, 24-NOV-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".

   -CSPICE Version 2.0.2, 14-AUG-2006 (EDW)

       Replace mention of ldpool_c with furnsh_c.

   -CSPICE Version 2.0.1, 09-JAN-2002 (NJB)

       Documentation change: instances of the phrase "fast load"
       were replaced with "fast write."

   -CSPICE Version 2.0.0, 07-JUL-1998 (NJB)

       Segment number is now mapped from C to Fortran range.

   -CSPICE Version 1.0.0, 01-APR-1998 (NJB)

       Based on SPICELIB Version 1.0.1, 31-MAR-1998 (NJB)

Index_Entries

   finish a fast EK segment write
Fri Dec 31 18:41:05 2021