/* plussz.c - one of the simplest max objects you can make -rdd 2001
	(plussz is/was the name of a Hungarian vitamin C tablet-drink from the early 90s)
	
	this example is provided for musicians who want to learn to write their own Max externals but who only
	have rudimentary computer programming skills and feel somewhat overwhelmed by the other examples in the Max SDK
 
	this object has 2 inlets and one outlet
	it responds to ints in its inlets and the 'bang' message in the left inlet
	it responds to the 'assistance' message sent by Max when the mouse is positioned over an inlet or outlet
		(including an assistance method is optional, but strongly sugggested)
	it adds its input values together and outputs their sum

*/

#include "ext.h"  		// you must include this - it contains the external object's link to available Max functions

#define RES_ID 10102	// this is the resource ID used in the resource file plussz.rsrc

typedef struct plussz	// defines our object's internal variables for each instance in a patch
{
	t_object p_ob;		// object header - ALL objects MUST begin with this...
	long p_value0;		// int value - received from the left inlet and stored internally for each object instance
	long p_value1;		// int value - received from the right inlet and stored internally for each object instance
	void *p_outlet;		// outlet creation - inlets are automatic, but objects must "own" their own outlets
	
} t_plussz;

void *plussz_class;		// global pointer to the object class - so max can reference the object 

// these are prototypes for the methods that are defined below
void plussz_bang(t_plussz *x);
void plussz_int(t_plussz *x, long n);
void plussz_in1(t_plussz *x, long n);
void plussz_assist(t_plussz *x, void *b, long m, long a, char *s);
void *plussz_new(long n);

//--------------------------------------------------------------------------

void main(void)
{
	setup((t_messlist **)&plussz_class, (method)plussz_new, 0L, (short)sizeof(t_plussz), 0L, A_DEFLONG, 0); 
	// setup() loads our external into Max's memory so it can be used in a patch
	// plussz_new = object creation method defined below, A_DEFLONG = its (optional) arguement is a long (32-bit) int 
	
	addbang((method)plussz_bang);		// the method it uses when it gets a bang in the left inlet 
	addint((method)plussz_int);			// the method for an int in the left inlet (inlet 0) 
	addinx((method)plussz_in1, 1);		// the method for an int in the right inlet (inlet 1) 
	addmess((method)plussz_assist, "assist", A_CANT, 0); // (optional) assistance method needs to be declared like this
	
	rescopy('STR#', RES_ID);			// copy the 'STR#' resource from the resource file (used for assistance)
	
	post("plussz object loaded...",0);	// post any important info to the max window when our object is laoded
}

//--------------------------------------------------------------------------

void plussz_bang(t_plussz *x)		// x = reference to this instance of the object 
{
	long sum;						// local variable for this method
	
	sum = x->p_value0+x->p_value1;	// add left and right operands
	outlet_int(x->p_outlet, sum);	// send out the sum on bang 
}

//--------------------------------------------------------------------------

void plussz_int(t_plussz *x, long n)	// x = the instance of the object; n = the int received in the left inlet 
{
	long sum;							// local variable for this method
	
	x->p_value0 = n;					// store left operand value in instance's data structure
	sum = n + x->p_value1;				// add left and right operands

	outlet_int(x->p_outlet, sum);		// ... and send it out the outlet 
}

//--------------------------------------------------------------------------

void plussz_in1(t_plussz *x, long n)	// x = the instance of the object, n = the int received in the right inlet 
{
	x->p_value1 = n;					// just store right operand value in instance's data structure and do nothing else
}

//--------------------------------------------------------------------------

void plussz_assist(t_plussz *x, void *b, long m, long a, char *s) // 4 final arguments are always the same for the assistance method
{
	assist_string(RES_ID,m,a,1,3,s); 	// get text (character strings) from the 'STR#' resource we loaded
										// 1 = first text string for the inlets, 3 = first text string for the outlets
}

//--------------------------------------------------------------------------

void *plussz_new(long n)		// n = int argument typed into object box (A_DEFLONG) -- defaults to 0 if no args are typed
{
	t_plussz *x;				// local variable (pointer to a t_plussz data structure)

	x = (t_plussz *)newobject(plussz_class); // create a new instance of this object
	
	intin(x,1);					// create a second int inlet (leftmost inlet is automatic - all objects have one inlet by default)
	
	x->p_outlet = intout(x);	// create an int outlet and assign it to our outlet variable in the instance's data structure
	
	x->p_value0	= 0;			// set initial (default) left operand value in the instance's data structure
	x->p_value1	= n;			// set initial (default) right operand value (n = variable passed to plussz_new)
	
	post(" new plussz object instance added to patch...",0); // post important info to the max window when new instance is created
	
	return(x);					// return a reference to the object instance 
}