/* NAME
 *     fib_times_two.c
 *
 *     From the Illustra User Guide, p. 10-13.
 *
 * BUILD INSTRUCTIONS
 *
 *     OSF1:    cc -I$MI_HOME/h -c fib_times_two.c
 *              ld -shared -expect_unresolved '*' -o fib_times_two.so \
 *              fib_times_two.o
 *
 *     Solaris: cc -I$MI_HOME/h -c -K PIC fib_times_two.c
 *              ld -dy -G -o fib_times_two.so fib_times_two.o
 *
 *     SUN OS:  cc -I$MI_HOME/h -c -PIC fib_times_two.c
 *              ld -o fib_times_two.so fib_times_two.o
 *
 *     chmod a+x fib_times_two.so
 *
 * DATABASE CREATE
 *     create function fib_times_two (setof(integer)) returns setof(integer)
 *     as external name '/FULL_PATH/fib_times_two.so' language c;
 *
 * SAMPLE USAGE
 *     * begin transaction;
 *     + return (fib_times_two(fib(71169))) as fib;
 *     ---------------
 *     |fib          |
 *     ---------------
 *     |fib_1_12_0   |
 *     ---------------
 *     one row selected
 *     + fetch from fib_1_12_0 all;
 *     ---------------
 *     |integer      |
 *     ---------------
 *     |0            |
 *     |2            |
 *     |2            |
 *     |4            |
 *     |6            |
 *     |10           |
 *     |16           |
 *     |26           |
 *     |42           |
 *     |68           |
 *     .....
 *     ---------------
 *     25 rows fetched
 *     + end transaction;
 *
 * $Header: /usr/local/devel/montage/samples/functions/RCS/fib_times_two.c,v 1.1 1994/10/06 16:31:29 jta Exp $
 */

#include "mi.h"

int
fib_times_two(fibset, fParam)
    void      *fibset;
    MI_FPARAM *fParam;
{
    mi_boolean isNull, isDone;
    int next;

    switch(MI_FP_REQUEST(fParam)) {
        case SET_INIT:
            MI_FP_SETFUNCSTATE(fParam, (void *)fibset);
            break;
        case SET_RETONE:
            next = SetGetNext(MI_FP_FUNCSTATE(fParam), &isNull, &isDone);
            if (isDone) {
                MI_FP_SETISDONE(fParam, MI_TRUE);
                return 0;
            }
            if (isNull) {
                MI_FP_SETRETURNISNULL(fParam, MI_TRUE);
                return 0;
            }
            return (2*next);
        case SET_END:
            break;
    }
}