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Appendix: ottClient.cc

The C++ wrapper main program to the C functions is listed below. The functions performing the calculations are in ottFluxes.c.

/* File ottClient.cc, version 1.2, released  02/12/02 at 11:42:52 
   retrieved by SCCS 02/12/02 at 11:43:21     

C++ client code wrapper for C functions to calculate the Ott et al fluxes.

HISTORY 
021202 GIL remove un-used segments of the code.
021118 GIL add some comments
021115 GIL Initial version based on ex_client.cc
021114 GIL Removed support for complex functions
970803 JRF Initial version, well documented at 
             http://www.gb.nrao.edu/~rfisher/Glish/ex_client.html
DESCRIPTION
Rick Fisher created a very nice set of example code that allows an
observer to quickly create a interface from C to glish.
This function impliments the C++ wrapper to a simple C program to calculate
the Ott et al 1994 flux densities for a set of reference sources.

There are two steps in the process:  First is setting the source name
for which the values are calculated.  The second step is providing
an array of frequencies (Hz), for which the flux densities are required.
*/

#include <stdio.h>
#include <string.h>
#include <math.h>
#include "Glish/Client.h"

// Declare all of the C/C++ functions that you are going to use or put
// the main() function at the end.
void setFluxes(Client &c, GlishEvent *e);
void setSource(Client &c, GlishEvent *e);

extern "C" {
  char * setOttSourceName( char * source);
  char * setOttSourceFluxes( long n, double values[]);
} /* end of C declares */

int main (int argc, char **argv) {
    // This creates a required client object.
    Client c(argc, argv);
    // The client can be invoked with arguments, but we`ll bypass that
    // complication.
    if (argc > 1) {                     /* if any argument, explain usage */
        printf ("Usage: cl := client('ex_client')\n");
        return 1;
    } /* end if an argument */
    // Create a pointer to be assigned to a received glish event.
    GlishEvent *e;

    // Stay in this loop until the client is terminated.  The c.NextEvent()
    // function blocks until it receives an event from glish.  It then
    // returns an event pointer that is used to access the values passed
    // from glish.
    while ((e = c.NextEvent())) {
        // Search for an expected event name and execute the appropriate
        // function when found.
// vvvvvvvvvvvv Your code substituted below here. vvvvvvvvvvvv
        if (!strcmp(e->Name(), "ottSetSource")) {
	  setSource( c, e);
        } else if (!strcmp(e->Name(), "ottSetFlux")) {
          setFluxes( c, e);
// ^^^^^^^^^^^^ Your code substituted above here. ^^^^^^^^^^^^
        } else {
            // Report an error if an event name is not recognized.
            c.Unrecognized();
        }
    }
    return 0;
} /* end of client main() */

void setFluxes(Client &c, GlishEvent *e)
{
    // See do_int_squared() function for comments on statements which
    // are common to all functions.
    Value *val = e->Val();
    long array_length = val->Length(), i = 0;
    double *return_value = new double[array_length];

    for (i = 0; i < array_length; i++)     /* default value is 1. */
        return_value[i] = 1.0;

    if (val->Type() != TYPE_DOUBLE || array_length <= 1) {
        printf("Double type array expected from `setFluxes'\n");
    } else {
        double * dataValues = val->DoublePtr();
        double * freqFluxes = new double[array_length];
// vvvvvvvvvvvv Your code substituted below here. vvvvvvvvvvvv
        for (i = 0; i < array_length; i++) 
          freqFluxes[i] = dataValues[i];
        
        setOttSourceFluxes( array_length, freqFluxes);
        for (i = 0; i < array_length; i++)  /* transfer out */
          return_value[i] = freqFluxes[i];
// ^^^^^^^^^^^^ Your code substituted above here. ^^^^^^^^^^^^
        delete freqFluxes;
    } /* end else if data of expected type */
    Value *rep = new Value(return_value, array_length, COPY_ARRAY);
    c.Reply(rep);
    delete return_value;
    Unref(rep);
} /* end of setFluxes() */

#define MAXSIZE 100                   /* set string max size */
void setSource(Client &c, GlishEvent *e) {
    // setSource() takes the source name event and transfers the name to the C 
    // functions.
    Value *val = e->Val();
    char return_value[MAXSIZE] = "", sourceName[MAXSIZE] = "", * errMsg = '\0';

    if (val->Type() != TYPE_STRING) {
        printf("String type value expected from `reverse_string'\n");
    } else {
        char *received_value = val->StringVal();
        strncpy( sourceName, received_value, MAXSIZE);
        sourceName[MAXSIZE-1] = '\0';
        // The call of val->StringVal() implicitly allocates memory
        // for the string which must be deleted to avoid a memory leak.
        delete received_value;
// vvvvvvvvvvvv Your code substituted below here. vvvvvvvvvvvv
        errMsg = setOttSourceName( sourceName);
        if (errMsg != '\0')                /* check for error strings */
	  strcpy( return_value, "!!!! ");
	strcat( return_value, sourceName);
// ^^^^^^^^^^^^ Your code substituted above here. ^^^^^^^^^^^^
    }
    Value *rep = new Value(return_value);
    c.Reply(rep);
    Unref(rep);
} /* end of setSource() */