/*
 * Implement the ternary operator MAD (multiply-add)
 * mad(a, b, c) returns (a*b)+c
 */

PyObject *mad(PyObject *self, PyObject *args)
{
    int i, length = -1;
    float *arrays[3], f[3];
    int which = 0;
    extern void doMADvvv(), doMADvvs(), doMADvsv(), doMADvss(), doMADsvv(), doMADsvs(), doMADssv();
    utility funcs[7] = {
        doMADvvv,
        doMADvvs,
        doMADvsv,
        doMADvss,
        doMADsvv,
        doMADsvs,
        doMADssv
    };

    if (PyTuple_Size(args) != 3) {
        PyErr_SetString(PyExc_TypeError, "too few arguments");
        return NULL;
    }

    // decide if each argument is a scalar or a vector, compute 'which' and
    // set up 'arrays' 

    for (i = 0; i < 3; i++) {
        PyObject *it = PyTuple_GetItem(args, i);
        if (Vop_Check(it)) {
            // First vector: set the length.  For subsequent vectors,
            // want to check that they have matching length
            if (length == -1)
                length = Vop_truelength(it);
            else if (length != Vop_truelength(it)) {
                PyErr_SetString(PyExc_TypeError, "mismatching lengths");
                return NULL;
            }
            arrays[i] = ((Vop*)it)->data;
        } else if (PyFloat_Check(it)) {
            f[i] = PyFloat_AsDouble(it);
            arrays[i] = &f[i];
            which += (4 >> i);
        } else {
            PyErr_SetString(PyExc_TypeError, "expecting vector or float");
            return NULL;
        }
    }
    if (which < 7) {
        Vop *r = (Vop*)Vop_NEW(length);

        odometer += 3 * length;
        (funcs[which])(r->data, arrays, length);
        
        return (PyObject *)r;
    } else {
        // all scalar arguments, so just do the operation here
        return PyFloat_FromDouble(f[0] * f[1] + f[2]);
    }
}