+ struct GNUNET_HashCode key_check;
+
+ GNUNET_CRYPTO_hash (proof, strlen (proof), &key_check);
+ return (0 ==
+ GNUNET_CRYPTO_hash_cmp (key, &key_check)) ? GNUNET_OK : GNUNET_NO;
+}
+
+
+/**
+ * Recursive helper function for iterate_initial_edges. Will call iterator
+ * function for each initial state.
+ *
+ * @param min_len minimum length of the path in the graph.
+ * @param max_len maximum length of the path in the graph.
+ * @param cur_len current length of the path already traversed.
+ * @param consumed_string string consumed by traversing the graph till this state.
+ * @param state current state of the automaton.
+ * @param iterator iterator function called for each edge.
+ * @param iterator_cls closure for the iterator function.
+ */
+static void
+iterate_initial_edge (const unsigned int min_len, const unsigned int max_len,
+ unsigned int cur_len, char *consumed_string,
+ struct GNUNET_REGEX_State *state,
+ GNUNET_REGEX_KeyIterator iterator, void *iterator_cls)
+{
+ unsigned int i;
+ char label[state->transition_count][2];
+ char *temp;
+ struct GNUNET_REGEX_Transition *t;
+ unsigned int num_edges = state->transition_count;
+ struct GNUNET_REGEX_Edge edges[num_edges];
+ struct GNUNET_HashCode hash;
+
+ if (cur_len > min_len && NULL != consumed_string && cur_len <= max_len)
+ {
+ for (i = 0, t = state->transitions_head; NULL != t; t = t->next, i++)
+ {
+ label[i][0] = t->label;
+ label[i][1] = '\0';
+ edges[i].label = label[i];
+ edges[i].destination = t->to_state->hash;
+ }
+
+ GNUNET_CRYPTO_hash (consumed_string, strlen (consumed_string), &hash);
+ iterator (iterator_cls, &hash, consumed_string, state->accepting, num_edges,
+ edges);
+ }
+
+ if (cur_len < max_len)
+ {
+ cur_len++;
+ for (t = state->transitions_head; NULL != t; t = t->next)
+ {
+ if (NULL != consumed_string)
+ GNUNET_asprintf (&temp, "%s%c", consumed_string, t->label);
+ else
+ GNUNET_asprintf (&temp, "%c", t->label);
+
+ iterate_initial_edge (min_len, max_len, cur_len, temp, t->to_state,
+ iterator, iterator_cls);
+ GNUNET_free (temp);
+ }
+ }
+}
+
+
+/**
+ * Iterate over all initial edges that aren't actually part of the automaton.
+ * This is needed to find the initial states returned by
+ * GNUNET_REGEX_get_first_key. Iteration will start at the first branch state (a
+ * state that has more than one outgoing edge, can be the first state), because
+ * all previous states will have the same proof and be iterated over in
+ * iterate_all_edges.
+ *
+ * @param a the automaton for which the initial states should be computed.
+ * @param initial_len length of the initial state string.
+ * @param iterator iterator function called for each edge.
+ * @param iterator_cls closure for the iterator function.
+ */
+void
+iterate_initial_edges (struct GNUNET_REGEX_Automaton *a,
+ const unsigned int initial_len,
+ GNUNET_REGEX_KeyIterator iterator, void *iterator_cls)
+{
+ char *consumed_string;
+ char *temp;
+ struct GNUNET_REGEX_State *s;
+ unsigned int cur_len;
+
+ if (1 > initial_len)
+ return;
+
+ consumed_string = NULL;
+ s = a->start;
+ cur_len = 0;
+
+ if (1 == s->transition_count)
+ {
+ do
+ {
+ if (NULL != consumed_string)
+ {
+ temp = consumed_string;
+ GNUNET_asprintf (&consumed_string, "%s%c", consumed_string,
+ s->transitions_head->label);
+ GNUNET_free (temp);
+ }
+ else
+ GNUNET_asprintf (&consumed_string, "%c", s->transitions_head->label);
+
+ s = s->transitions_head->to_state;
+ cur_len++;
+ }
+ while (cur_len < initial_len && 1 == s->transition_count);
+ }
+
+ iterate_initial_edge (cur_len, initial_len, cur_len, consumed_string, s,
+ iterator, iterator_cls);
+
+ GNUNET_free_non_null (consumed_string);