
#include <grass/gis.h>
#include "globals.h"
#include "expression.h"
#include "func_proto.h"

/****************************************************************
mod(a,b) = a % b
****************************************************************/

int 
f_mod(int argc, const int *argt, void **args)
{
	int i;

	if (argc < 2)
		return E_ARG_LO;
	if (argc > 2)
		return E_ARG_HI;

	if (argt[1] != argt[0] || argt[2] != argt[0])
		return E_ARG_TYPE;

	switch (argt[0])
	{
	case CELL_TYPE:
	{
		CELL *res = args[0];
		CELL *arg1 = args[1];
		CELL *arg2 = args[2];
		for (i = 0; i < columns; i++)
		{
			if (IS_NULL_C(&arg1[i]) || IS_NULL_C(&arg2[i]))
				SET_NULL_C(&res[i]);
			else
				res[i] = arg1[i] % arg2[i];
		}
		return 0;
	}
	case FCELL_TYPE:
	{
		FCELL *res = args[0];
		FCELL *arg1 = args[1];
		FCELL *arg2 = args[2];
		for (i = 0; i < columns; i++)
		{
			if (IS_NULL_F(&arg1[i]) || IS_NULL_F(&arg2[i]))
				SET_NULL_F(&res[i]);
			else
			{
				int k;
				floating_point_exception = 0;
				k = (int) (arg1[i] / arg2[i]);
				if(floating_point_exception)
					SET_NULL_F(&res[i]);
				else
					res[i] = arg1[i] - k * arg2[i];
			}
		}
		return 0;
	}
	case DCELL_TYPE:
	{
		DCELL *res = args[0];
		DCELL *arg1 = args[1];
		DCELL *arg2 = args[2];
		for (i = 0; i < columns; i++)
		{
			if (IS_NULL_D(&arg1[i]) || IS_NULL_D(&arg2[i]))
				SET_NULL_D(&res[i]);
			else
			{
				int k;
				floating_point_exception = 0;
				k = (int) (arg1[i] / arg2[i]);
				if(floating_point_exception)
					SET_NULL_D(&res[i]);
				else
					res[i] = arg1[i] - k * arg2[i];
			}
		}
		return 0;
	}
	default:
		return E_INV_TYPE;
	}
}
