/* clone_graph:
* Create two copies of the argument graph
* One is a subgraph, the other is an actual copy since we will be
* adding edges to it.
*/
static Agraph_t*
clone_graph(Agraph_t* ing, Agraph_t** xg)
{
Agraph_t* clone;
Agraph_t* xclone;
Agnode_t* n;
Agnode_t* xn;
Agnode_t* xh;
Agedge_t* e;
Agedge_t* xe;
char gname[SMALLBUF];
static int id = 0;
sprintf (gname, "_clone_%d", id++);
clone = agsubg(ing, gname);
sprintf (gname, "_clone_%d", id++);
xclone = agopen(gname, ing->kind);
for(n = agfstnode(ing); n; n = agnxtnode(ing, n)) {
aginsert (clone, n);
xn = agnode (xclone, n->name);
CLONE(n) = xn;
}
for(n = agfstnode(ing); n; n = agnxtnode(ing, n)) {
xn = CLONE(n);
for(e = agfstout(ing, n); e; e = agnxtout(ing, e)) {
aginsert (clone, e);
xh = CLONE(e->head);
xe = agedge (xclone, xn, xh);
ORIGE(xe) = e;
DEGREE(xn) += 1;
DEGREE(xh) += 1;
}
}
*xg = xclone;
#ifdef OLD
clone = agopen("clone", root->kind);
for(n = agfstnode(root); n; n = agnxtnode(root, n)) {
cn = agnode(clone, n->name);
ND_alg(cn) = DATA(n);
BCDONE(cn) = 0;
}
for(n = agfstnode(root); n; n = agnxtnode(root, n)) {
Agnode_t *t = agnode(clone, n);
for(e = agfstout(root, n); e; e = agnxtout(root, e)) {
Agnode_t *h = agnode(clone, e->head->name);
agedge(clone, t, h);
}
}
#endif
return clone;
}
/* dfs:
*
* Current scheme adds articulation point to first non-trivial child
* block. If none exists, it will be added to its parent's block, if
* non-trivial, or else given its own block.
*
* FIX:
* This should be modified to:
* - allow user to specify which block gets a node, perhaps on per-node basis.
* - if an articulation point is not used in one of its non-trivial blocks,
* dummy edges should be added to preserve biconnectivity
* - turn on user-supplied blocks.
*
*/
static void dfs(Agraph_t * g, Agnode_t * n, circ_state * state, int isRoot)
{
Agedge_t *e;
Agnode_t *curtop;
LOWVAL(n) = VAL(n) = state->orderCount++;
stackPush(state->bcstack, n);
for (e = agfstedge(g, n); e; e = agnxtedge(g, e, n)) {
Agnode_t *neighbor = e->head;
if (neighbor == n)
neighbor = e->tail;
if (neighbor == PARENT(n))
continue;
if (VAL(neighbor)) {
LOWVAL(n) = min_value(LOWVAL(n), VAL(neighbor));
continue;
}
if (!stackCheck(state->bcstack, n)) {
stackPush(state->bcstack, n);
}
PARENT(neighbor) = n;
curtop = top(state->bcstack);
dfs(g, neighbor, state, 0);
LOWVAL(n) = min_value(LOWVAL(n), LOWVAL(neighbor));
if (LOWVAL(neighbor) >= VAL(n)) {
block_t *block = NULL;
Agnode_t *np;
if (top(state->bcstack) != curtop)
do {
np = stackPop(state->bcstack);
if (!BCDONE(np)) {
if (!block)
block = makeBlock(g, state);
addNode(block, np);
}
} while (np != n);
if (block) { /* If block != NULL, it's not empty */
if (isRoot && (BLOCK(n) == block))
insertBlock(&state->bl, block);
else
appendBlock(&state->bl, block);
}
if ((LOWVAL(n) < VAL(n)) && (!stackCheck(state->bcstack, n))) {
stackPush(state->bcstack, n);
}
}
}
if ((LOWVAL(n) == VAL(n)) && !BCDONE(n)) {
block_t *block = makeBlock(g, state);
stackPop(state->bcstack);
addNode(block, n);
if (isRoot)
insertBlock(&state->bl, block);
else
appendBlock(&state->bl, block);
}
}
/* find_blocks:
*/
static void find_blocks(Agraph_t * g, circ_state * state)
{
Agnode_t *n;
Agnode_t *root = NULL;
block_t *rootBlock = NULL;
blocklist_t ublks;
#ifdef USER_BLOCKS
graph_t *clust_subg;
graph_t *mg;
edge_t *me;
node_t *mm;
int isRoot;
#endif
initBlocklist(&ublks);
/* check to see if there is a node which is set to be the root
*/
if (state->rootname) {
root = agfindnode(g, state->rootname);
}
if (!root && state->N_root) {
for (n = agfstnode(g); n; n = agnxtnode(g, n)) {
if (late_bool(ORIGN(n), state->N_root, 0)) {
root = n;
break;
}
}
}
#ifdef USER_BLOCKS
/* process clusters first */
/* by construction, all subgraphs are blocks and are non-empty */
mm = g->meta_node;
mg = mm->graph;
for (me = agfstout(mg, mm); me; me = agnxtout(mg, me)) {
block_t *block;
clust_subg = agusergraph(me->head);
isRoot = 0;
block = mkBlock(clust_subg);
/* block = makeBlock(g, state); */
for (n = agfstnode(clust_subg); n; n = agnxtnode(clust_subg, n)) {
if (!BCDONE(n)) { /* test not necessary if blocks disjoint */
SET_BCDONE(n);
BLOCK(n) = block;
if (n == root)
isRoot = 1;
}
}
if (isRoot) {
/* Assume blocks are disjoint, so don't check if rootBlock is
* already assigned.
*/
rootBlock = block;
insertBlock(&state->bl, block);
} else {
appendBlock(&state->bl, block);
}
}
ublks.first = state->bl.first;
ublks.last = state->bl.last;
#endif
if (!root)
root = agfstnode(g);
dfs(g, root, state, !rootBlock);
#ifdef USER_BLOCKS
/* If g has user-supplied blocks, it may be disconnected.
* We then fall into the following ugly loop.
* We are guaranteed !VISITED(n) and PARENT(n) has been
* set to a visited node.
*/
if (ublks.first) {
while (n = findUnvisited(&ublks)) {
dfs(g, n, state, 0);
}
}
#endif
}
