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#include <gran/mesh/node.h>
struct reg {
struct packet pkt;
bool busy;
};
struct node {
struct component component;
uint16_t x, y;
uint64_t timestamp;
struct component *n, *s, *e, *w, *l;
struct reg n_in, s_in, e_in, w_in, l_in;
};
enum order {
N, S, E, W, L
};
static inline void maybe_pick(struct reg *output[5], enum order d, struct reg *r)
{
if (output[d] && output[d]->pkt.timestamp < r->pkt.timestamp)
return;
output[d] = r;
}
static stat node_clock(struct node *node)
{
node->timestamp++;
struct reg *output[5] = {NULL, NULL, NULL, NULL, NULL};
struct reg *input[5] = {
&node->n_in,
&node->s_in,
&node->e_in,
&node->w_in,
&node->l_in
};
uint8_t X = node->x, Y = node->y;
for (size_t i = 0; i < 5; ++i) {
struct reg *r = input[i];
if (!r->busy)
continue;
uint16_t x, y;
addr_mesh(r->pkt.to, &x, &y, NULL);
if (x < X) {
maybe_pick(output, W, r);
continue;
}
if (x > X) {
maybe_pick(output, E, r);
continue;
}
if (y < Y) {
maybe_pick(output, S, r);
continue;
}
if (y > Y) {
maybe_pick(output, N, r);
continue;
}
maybe_pick(output, L, r);
}
struct component *target[7] = {
node->n,
node->s,
node->e,
node->w,
node->l
};
for (size_t i = 0; i < 5; ++i) {
if (!output[i])
continue;
if (!target[i]) {
/* for now, should send packet back with an error or something */
abort();
}
stat ret = SEND(node, target[i], output[i]->pkt);
if (ret == EBUSY)
continue;
assert(ret == OK);
output[i]->busy = false;
}
return OK;
}
static stat reg_receive(struct reg *r, struct packet pkt)
{
if (r->busy)
return EBUSY;
r->pkt = pkt;
r->busy = true;
return OK;
}
static stat node_receive(struct node *node, struct component *from, struct packet pkt)
{
if (from == node->l) {
/* add time when packet entered network */
pkt.timestamp = node->timestamp;
return reg_receive(&node->l_in, pkt);
}
if (from == node->n)
return reg_receive(&node->n_in, pkt);
if (from == node->s)
return reg_receive(&node->s_in, pkt);
if (from == node->e)
return reg_receive(&node->e_in, pkt);
if (from == node->w)
return reg_receive(&node->w_in, pkt);
abort();
return OK;
}
struct component *create_mesh_node(uint16_t x, uint16_t y)
{
struct node *node = calloc(1, sizeof(struct node));
if (!node)
return NULL;
node->component.receive = (receive_callback)node_receive;
node->component.clock = (clock_callback)node_clock;
node->x = x;
node->y = y;
return (struct component *)node;
}
stat mesh_node_connect(struct component *node,
struct component *n,
struct component *s,
struct component *e,
struct component *w,
struct component *l)
{
struct node *nod = (struct node *)node;
nod->n = n;
nod->s = s;
nod->e = e;
nod->w = w;
nod->l = l;
return OK;
}
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