/* NAME
 *     math_func.c
 *
 * DESCRIPTION
 *
 *     Sample function that links the sin() function into Illustra:
 *          -  checks for NULL input parameters 
 *          -  initializes return value to NULL
 *          -  allocates the return value only once
 *          -  overloads the function with a debug option
 *             NOTE: Debug messages also get output to 
 *                   $MI_HOME/data/miserver.log
 *
 *     If anybody knows how to handle numeric errors, send email to 
 *     jta@postgres.berkeley.edu.
 *
 * SAMPLE USAGE
 *
 *     return sin(.12345);
 *     return sin(.12345, 1); -- outputs debug messages
 *
 * BUILD INSTRUCTIONS
 *
 *     OSF1:
 *          cc -I$MI_HOME/h -c math_func.c
 *          ld -shared -expect_unresolved '*' -o math_func.so math_func.o
 *
 *     Solaris:
 *          cc -I$MI_HOME/h -c -K PIC math_func.c
 *          ld -dy -G -o math_func.so math_func.o
 *
 *     SUN OS:
 *          cc -I$MI_HOME/h -c -PIC math_func.c
 *          ld -o math_func.so math_func.o
 *
 *     chmod a+x math_func.so
 *
 * DATABASE CREATE
 *
 *     drop function sin (double precision);
 *     create function sin (double precision) returns double precision
 *        as external name '/FULL_PATH/math_func.so(osf1_sin_n)'
 *        language C;
 *
 *     drop function sin (double precision, integer);
 *     create function sin (double precision, integer) returns double precision
 *        as external name '/FULL_PATH/math_func.so(osf1_sin)'
 *        language C;
 *
 * MODS
 *     4/11/94 jta   works with Montage 2.0.9, libmontage '3.0.1 M'
 *     6/07/94 jta   upgraded to Illustra 2.0.12
 *     7/22/94 jta   works with 2.1
 *
 * $Header: /usr/local/devel/montage/samples/functions/RCS/math_func.c,v 1.3 1994/07/22 23:12:44 jta Exp $
 */

#include <math.h>
#include <errno.h>
#include "mi.h"

mi_double_precision * 
     osf1_sin_n ARGS((mi_double_precision *x, MI_FPARAM *fParam));
mi_double_precision * 
     osf1_sin   ARGS((mi_double_precision *x, int debug, MI_FPARAM *fParam));

mi_double_precision *
osf1_sin_n(x, fParam)
mi_double_precision *x;
MI_FPARAM           *fParam;
{
     return ( osf1_sin (x, 0, fParam) );
}

mi_double_precision *
osf1_sin(x, debug, fParam)
mi_double_precision   *x;
int                   debug;
MI_FPARAM             *fParam;
{
     char                 msg_buf[100];
     mi_double_precision  *retval;
     MI_CONNECTION        *conn;

     MI_FP_SETRETURNISNULL(fParam, MI_TRUE); /* initialize to return null */

     if (MI_FP_ARGISNULL(fParam, 0))         /* return if x is NULL */
          return(NULL);

     if ((conn = mi_open(NULL, NULL, NULL)) == (MI_CONNECTION *) NULL)
          mi_db_error_raise(conn, MI_EXCEPTION, 
               "osf1_sin: couldn't get a libmi connection");

     /* mi_alloc retval once and reuse rather than mi_alloc each return. */

     if((retval = (mi_double_precision *) MI_FP_FUNCSTATE(fParam)) == 0) 
     {
          retval = (mi_double_precision *) mi_alloc(sizeof(mi_double_precision));
          mi_set_mem_duration ((void *) retval, PER_COMMAND);
          MI_FP_SETFUNCSTATE (fParam, (void *) retval);
     }

     *retval = HUGE_VAL;           /* initialize to infinity */

     errno = 0;

     *retval = sin(*x);

     if (errno != 0) {
         strncpy(msg_buf, strerror(errno), sizeof(msg_buf) - 1);
         mi_db_error_raise(conn, MI_NOTICE, msg_buf);
     }
     else
          MI_FP_SETRETURNISNULL(fParam, MI_FALSE);

     if(debug) {
         sprintf(msg_buf, "osf1_sin: The sin of %g is %g", *x, *retval);
         mi_db_error_raise(conn, MI_NOTICE, msg_buf);
     }

     return (retval);
}