Function proceed_next_node

compat/regex/regexec.c:1249–1347

/* Compute the next node to which "NFA" transit from NODE("NFA" is a NFA
   corresponding to the DFA).
   Return the destination node, and update EPS_VIA_NODES, return -1 in case
   of errors.  */

static int
internal_function
proceed_next_node (const re_match_context_t *mctx, int nregs, regmatch_t *regs,
		   int *pidx, int node, re_node_set *eps_via_nodes,
		   struct re_fail_stack_t *fs)
{
  const re_dfa_t *const dfa = mctx->dfa;
  int i, err;
  if (IS_EPSILON_NODE (dfa->nodes[node].type))
    {
      re_node_set *cur_nodes = &mctx->state_log[*pidx]->nodes;
      re_node_set *edests = &dfa->edests[node];
      int dest_node;
      err = re_node_set_insert (eps_via_nodes, node);
      if (BE (err < 0, 0))
	return -2;
      /* Pick up a valid destination, or return -1 if none is found.  */
      for (dest_node = -1, i = 0; i < edests->nelem; ++i)
	{
	  int candidate = edests->elems[i];
	  if (!re_node_set_contains (cur_nodes, candidate))
	    continue;
	  if (dest_node == -1)
	    dest_node = candidate;

	  else
	    {
	      /* In order to avoid infinite loop like "(a*)*", return the second
		 epsilon-transition if the first was already considered.  */
	      if (re_node_set_contains (eps_via_nodes, dest_node))
		return candidate;

	      /* Otherwise, push the second epsilon-transition on the fail stack.  */
	      else if (fs != NULL
		       && push_fail_stack (fs, *pidx, candidate, nregs, regs,
					   eps_via_nodes))
		return -2;

	      /* We know we are going to exit.  */
	      break;
	    }
	}
      return dest_node;
    }
  else
    {
      int naccepted = 0;
      re_token_type_t type = dfa->nodes[node].type;

#ifdef RE_ENABLE_I18N
      if (dfa->nodes[node].accept_mb)
	naccepted = check_node_accept_bytes (dfa, node, &mctx->input, *pidx);
      else
#endif /* RE_ENABLE_I18N */
      if (type == OP_BACK_REF)