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21 * @file src/regex/regex.c
22 * @brief library to create automatons from regular expressions
23 * @author Maximilian Szengel
26 #include "gnunet_container_lib.h"
27 #include "gnunet_crypto_lib.h"
28 #include "gnunet_regex_lib.h"
31 #define initial_bits 10
34 * Context that contains an id counter for states and transitions as well as a
35 * DLL of automatons used as a stack for NFA construction.
37 struct GNUNET_REGEX_Context
42 unsigned int state_id;
45 * Unique transition id.
47 unsigned int transition_id;
50 * Unique SCC (Strongly Connected Component) id.
55 * DLL of GNUNET_REGEX_Automaton's used as a stack.
57 struct GNUNET_REGEX_Automaton *stack_head;
60 * DLL of GNUNET_REGEX_Automaton's used as a stack.
62 struct GNUNET_REGEX_Automaton *stack_tail;
66 * Type of an automaton.
68 enum GNUNET_REGEX_automaton_type
75 * Automaton representation.
77 struct GNUNET_REGEX_Automaton
80 * This is a linked list.
82 struct GNUNET_REGEX_Automaton *prev;
85 * This is a linked list.
87 struct GNUNET_REGEX_Automaton *next;
90 * First state of the automaton. This is mainly used for constructing an NFA,
91 * where each NFA itself consists of one or more NFAs linked together.
93 struct GNUNET_REGEX_State *start;
96 * End state of the automaton.
98 struct GNUNET_REGEX_State *end;
101 * Number of states in the automaton.
103 unsigned int state_count;
108 struct GNUNET_REGEX_State *states_head;
113 struct GNUNET_REGEX_State *states_tail;
116 * Type of the automaton.
118 enum GNUNET_REGEX_automaton_type type;
122 * A state. Can be used in DFA and NFA automatons.
124 struct GNUNET_REGEX_State
127 * This is a linked list.
129 struct GNUNET_REGEX_State *prev;
132 * This is a linked list.
134 struct GNUNET_REGEX_State *next;
142 * If this is an accepting state or not.
147 * Marking of the state. This is used for marking all visited states when
148 * traversing all states of an automaton and for cases where the state id
149 * cannot be used (dfa minimization).
154 * Marking the state as contained. This is used for checking, if the state is
155 * contained in a set in constant time
160 * Marking the state as part of an SCC (Strongly Connected Component). All
161 * states with the same scc_id are part of the same SCC. scc_id is 0, if state
162 * is not a part of any SCC.
167 * Used for SCC detection.
172 * Used for SCC detection.
177 * Human readable name of the automaton. Used for debugging and graph
185 GNUNET_HashCode hash;
188 * Proof for this state.
193 * Number of transitions from this state to other states.
195 unsigned int transition_count;
198 * DLL of transitions.
200 struct Transition *transitions_head;
203 * DLL of transitions.
205 struct Transition *transitions_tail;
208 * Set of states on which this state is based on. Used when creating a DFA out
209 * of several NFA states.
211 struct GNUNET_REGEX_StateSet *nfa_set;
215 * Transition between two states. Each state can have 0-n transitions. If label
216 * is 0, this is considered to be an epsilon transition.
221 * This is a linked list.
223 struct Transition *prev;
226 * This is a linked list.
228 struct Transition *next;
231 * Unique id of this transition.
236 * Label for this transition. This is basically the edge label for the graph.
241 * State to which this transition leads.
243 struct GNUNET_REGEX_State *to_state;
246 * State from which this transition origins.
248 struct GNUNET_REGEX_State *from_state;
251 * Mark this transition. For example when reversing the automaton.
259 struct GNUNET_REGEX_StateSet
264 struct GNUNET_REGEX_State **states;
267 * Length of the 'states' array.
273 * Debug helper functions
276 debug_print_transitions (struct GNUNET_REGEX_State *);
279 debug_print_state (struct GNUNET_REGEX_State *s)
283 if (NULL == s->proof)
288 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
289 "State %i: %s marked: %i accepting: %i scc_id: %i transitions: %i proof: %s\n",
290 s->id, s->name, s->marked, s->accepting, s->scc_id,
291 s->transition_count, proof);
293 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Transitions:\n");
294 debug_print_transitions (s);
298 debug_print_states (struct GNUNET_REGEX_Automaton *a)
300 struct GNUNET_REGEX_State *s;
302 for (s = a->states_head; NULL != s; s = s->next)
303 debug_print_state (s);
307 debug_print_transition (struct Transition *t)
321 if (NULL == t->to_state)
324 to_state = t->to_state->name;
326 if (NULL == t->from_state)
329 from_state = t->from_state->name;
331 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Transition %i: From %s on %c to %s\n",
332 t->id, from_state, label, to_state);
336 debug_print_transitions (struct GNUNET_REGEX_State *s)
338 struct Transition *t;
340 for (t = s->transitions_head; NULL != t; t = t->next)
341 debug_print_transition (t);
345 * Recursive function doing DFS with 'v' as a start, detecting all SCCs inside
346 * the subgraph reachable from 'v'. Used with scc_tarjan function to detect all
347 * SCCs inside an automaton.
350 * @param v start vertex
351 * @param index current index
352 * @param stack stack for saving all SCCs
353 * @param stack_size current size of the stack
356 scc_tarjan_strongconnect (struct GNUNET_REGEX_Context *ctx,
357 struct GNUNET_REGEX_State *v, int *index,
358 struct GNUNET_REGEX_State **stack,
359 unsigned int *stack_size)
361 struct GNUNET_REGEX_State *w;
362 struct Transition *t;
367 stack[(*stack_size)++] = v;
370 for (t = v->transitions_head; NULL != t; t = t->next)
373 if (NULL != w && w->index < 0)
375 scc_tarjan_strongconnect (ctx, w, index, stack, stack_size);
376 v->lowlink = (v->lowlink > w->lowlink) ? w->lowlink : v->lowlink;
378 else if (0 != w->contained)
379 v->lowlink = (v->lowlink > w->index) ? w->index : v->lowlink;
382 if (v->lowlink == v->index)
384 w = stack[--(*stack_size)];
392 w->scc_id = ctx->scc_id;
393 w = stack[--(*stack_size)];
396 w->scc_id = ctx->scc_id;
402 * Detect all SCCs (Strongly Connected Components) inside the given automaton.
403 * SCCs will be marked using the scc_id on each state.
409 scc_tarjan (struct GNUNET_REGEX_Context *ctx, struct GNUNET_REGEX_Automaton *a)
412 struct GNUNET_REGEX_State *v;
413 struct GNUNET_REGEX_State *stack[a->state_count];
414 unsigned int stack_size;
416 for (v = a->states_head; NULL != v; v = v->next)
426 for (v = a->states_head; NULL != v; v = v->next)
429 scc_tarjan_strongconnect (ctx, v, &index, stack, &stack_size);
434 * Adds a transition from one state to another on 'label'. Does not add
438 * @param from_state starting state for the transition
439 * @param label transition label
440 * @param to_state state to where the transition should point to
443 state_add_transition (struct GNUNET_REGEX_Context *ctx,
444 struct GNUNET_REGEX_State *from_state, const char label,
445 struct GNUNET_REGEX_State *to_state)
448 struct Transition *t;
450 if (NULL == from_state)
452 GNUNET_log (GNUNET_ERROR_TYPE_ERROR, "Could not create Transition.\n");
456 // Do not add duplicate state transitions
458 for (t = from_state->transitions_head; NULL != t; t = t->next)
460 if (t->to_state == to_state && t->label == label &&
461 t->from_state == from_state)
471 t = GNUNET_malloc (sizeof (struct Transition));
472 t->id = ctx->transition_id++;
474 t->to_state = to_state;
475 t->from_state = from_state;
477 // Add outgoing transition to 'from_state'
478 from_state->transition_count++;
479 GNUNET_CONTAINER_DLL_insert (from_state->transitions_head,
480 from_state->transitions_tail, t);
484 * Compare two states. Used for sorting.
486 * @param a first state
487 * @param b second state
489 * @return an integer less than, equal to, or greater than zero
490 * if the first argument is considered to be respectively
491 * less than, equal to, or greater than the second.
494 state_compare (const void *a, const void *b)
496 struct GNUNET_REGEX_State **s1;
497 struct GNUNET_REGEX_State **s2;
499 s1 = (struct GNUNET_REGEX_State **) a;
500 s2 = (struct GNUNET_REGEX_State **) b;
502 return (*s1)->id - (*s2)->id;
506 * Get all edges leaving state 's'.
509 * @param edges all edges leaving 's'.
511 * @return number of edges.
514 state_get_edges (struct GNUNET_REGEX_State *s, struct GNUNET_REGEX_Edge *edges)
516 struct Transition *t;
524 for (t = s->transitions_head; NULL != t; t = t->next)
526 if (NULL != t->to_state)
528 edges[count].label = &t->label;
529 edges[count].destination = t->to_state->hash;
537 * Compare to state sets by comparing the id's of the states that are contained
538 * in each set. Both sets are expected to be sorted by id!
540 * @param sset1 first state set
541 * @param sset2 second state set
543 * @return an integer less than, equal to, or greater than zero
544 * if the first argument is considered to be respectively
545 * less than, equal to, or greater than the second.
548 state_set_compare (struct GNUNET_REGEX_StateSet *sset1,
549 struct GNUNET_REGEX_StateSet *sset2)
554 if (NULL == sset1 || NULL == sset2)
557 result = sset1->len - sset2->len;
559 for (i = 0; i < sset1->len; i++)
564 result = state_compare (&sset1->states[i], &sset2->states[i]);
570 * Clears the given StateSet 'set'
572 * @param set set to be cleared
575 state_set_clear (struct GNUNET_REGEX_StateSet *set)
579 if (NULL != set->states)
580 GNUNET_free (set->states);
586 * Clears an automaton fragment. Does not destroy the states inside the
589 * @param a automaton to be cleared
592 automaton_fragment_clear (struct GNUNET_REGEX_Automaton *a)
599 a->states_head = NULL;
600 a->states_tail = NULL;
606 * Frees the memory used by State 's'
608 * @param s state that should be destroyed
611 automaton_destroy_state (struct GNUNET_REGEX_State *s)
613 struct Transition *t;
614 struct Transition *next_t;
620 GNUNET_free (s->name);
622 if (NULL != s->proof)
623 GNUNET_free (s->proof);
625 for (t = s->transitions_head; NULL != t; t = next_t)
628 GNUNET_CONTAINER_DLL_remove (s->transitions_head, s->transitions_tail, t);
632 state_set_clear (s->nfa_set);
638 * Remove a state from the given automaton 'a'. Always use this function when
639 * altering the states of an automaton. Will also remove all transitions leading
640 * to this state, before destroying it.
643 * @param s state to remove
646 automaton_remove_state (struct GNUNET_REGEX_Automaton *a,
647 struct GNUNET_REGEX_State *s)
649 struct GNUNET_REGEX_State *ss;
650 struct GNUNET_REGEX_State *s_check;
651 struct Transition *t_check;
653 if (NULL == a || NULL == s)
658 GNUNET_CONTAINER_DLL_remove (a->states_head, a->states_tail, s);
661 // remove all transitions leading to this state
662 for (s_check = a->states_head; NULL != s_check; s_check = s_check->next)
664 for (t_check = s_check->transitions_head; NULL != t_check;
665 t_check = t_check->next)
667 if (t_check->to_state == ss)
669 GNUNET_CONTAINER_DLL_remove (s_check->transitions_head,
670 s_check->transitions_tail, t_check);
671 s_check->transition_count--;
676 automaton_destroy_state (ss);
680 * Merge two states into one. Will merge 's1' and 's2' into 's1' and destroy
685 * @param s1 first state
686 * @param s2 second state, will be destroyed
689 automaton_merge_states (struct GNUNET_REGEX_Context *ctx,
690 struct GNUNET_REGEX_Automaton *a,
691 struct GNUNET_REGEX_State *s1,
692 struct GNUNET_REGEX_State *s2)
694 struct GNUNET_REGEX_State *s_check;
695 struct Transition *t_check;
698 GNUNET_assert (NULL != ctx && NULL != a && NULL != s1 && NULL != s2);
703 // 1. Make all transitions pointing to s2 point to s1
704 for (s_check = a->states_head; NULL != s_check; s_check = s_check->next)
706 for (t_check = s_check->transitions_head; NULL != t_check;
707 t_check = t_check->next)
709 if (s2 == t_check->to_state)
710 t_check->to_state = s1;
714 // 2. Add all transitions from s2 to sX to s1
715 for (t_check = s2->transitions_head; NULL != t_check; t_check = t_check->next)
717 if (t_check->to_state != s1)
718 state_add_transition (ctx, s1, t_check->label, t_check->to_state);
721 // 3. Rename s1 to {s1,s2}
722 new_name = GNUNET_strdup (s1->name);
723 if (NULL != s1->name)
725 GNUNET_free (s1->name);
728 GNUNET_asprintf (&s1->name, "{%s,%s}", new_name, s2->name);
729 GNUNET_free (new_name);
732 GNUNET_CONTAINER_DLL_remove (a->states_head, a->states_tail, s2);
734 automaton_destroy_state (s2);
738 * Add a state to the automaton 'a', always use this function to alter the
739 * states DLL of the automaton.
741 * @param a automaton to add the state to
742 * @param s state that should be added
745 automaton_add_state (struct GNUNET_REGEX_Automaton *a,
746 struct GNUNET_REGEX_State *s)
748 GNUNET_CONTAINER_DLL_insert (a->states_head, a->states_tail, s);
753 * Function that is called with each state, when traversing an automaton.
758 typedef void (*GNUNET_REGEX_traverse_action) (void *cls,
759 struct GNUNET_REGEX_State * s);
762 * Traverses all states that are reachable from state 's'. Expects the states to
763 * be unmarked (s->marked == GNUNET_NO). Performs 'action' on each visited
766 * @param cls closure.
767 * @param s start state.
768 * @param action action to be performed on each state.
771 automaton_state_traverse (void *cls, struct GNUNET_REGEX_State *s,
772 GNUNET_REGEX_traverse_action action)
774 struct Transition *t;
776 if (GNUNET_NO == s->marked)
778 s->marked = GNUNET_YES;
783 for (t = s->transitions_head; NULL != t; t = t->next)
784 automaton_state_traverse (cls, t->to_state, action);
789 * Traverses the given automaton from it's start state, visiting all reachable
790 * states and calling 'action' on each one of them.
792 * @param cls closure.
793 * @param a automaton.
794 * @param action action to be performed on each state.
797 automaton_traverse (void *cls, struct GNUNET_REGEX_Automaton *a,
798 GNUNET_REGEX_traverse_action action)
800 struct GNUNET_REGEX_State *s;
802 for (s = a->states_head; NULL != s; s = s->next)
803 s->marked = GNUNET_NO;
805 automaton_state_traverse (cls, a->start, action);
809 * Reverses all transitions of the given automaton.
811 * @param a automaton.
814 automaton_reverse (struct GNUNET_REGEX_Automaton *a)
816 struct GNUNET_REGEX_State *s;
817 struct Transition *t;
818 struct Transition *t_next;
819 struct GNUNET_REGEX_State *s_swp;
821 for (s = a->states_head; NULL != s; s = s->next)
822 for (t = s->transitions_head; NULL != t; t = t->next)
825 for (s = a->states_head; NULL != s; s = s->next)
827 for (t = s->transitions_head; NULL != t; t = t_next)
831 if (GNUNET_YES == t->mark || t->from_state == t->to_state)
834 t->mark = GNUNET_YES;
836 GNUNET_CONTAINER_DLL_remove (t->from_state->transitions_head,
837 t->from_state->transitions_tail, t);
838 t->from_state->transition_count--;
839 GNUNET_CONTAINER_DLL_insert (t->to_state->transitions_head,
840 t->to_state->transitions_tail, t);
841 t->to_state->transition_count++;
843 s_swp = t->from_state;
844 t->from_state = t->to_state;
851 * Create proof for the given state.
853 * @param cls closure.
857 automaton_create_proofs_step (void *cls, struct GNUNET_REGEX_State *s)
859 struct Transition *t;
863 for (i = 0, t = s->transitions_head; NULL != t; t = t->next, i++)
865 if (t->to_state == s)
866 GNUNET_asprintf (&tmp, "%c*", t->label);
867 else if (i != s->transition_count - 1)
868 GNUNET_asprintf (&tmp, "%c|", t->label);
870 GNUNET_asprintf (&tmp, "%c", t->label);
872 if (NULL != s->proof)
874 GNUNET_realloc (s->proof, strlen (s->proof) + strlen (tmp) + 1);
876 s->proof = GNUNET_malloc (strlen (tmp) + 1);
877 strcat (s->proof, tmp);
883 * Create proofs for all states in the given automaton.
885 * @param a automaton.
888 automaton_create_proofs (struct GNUNET_REGEX_Automaton *a)
890 struct GNUNET_REGEX_State *s;
892 automaton_reverse (a);
894 for (s = a->states_head; NULL != s; s = s->next)
895 automaton_create_proofs_step (NULL, s);
897 automaton_reverse (a);
901 * Creates a new DFA state based on a set of NFA states. Needs to be freed using
902 * automaton_destroy_state.
905 * @param nfa_states set of NFA states on which the DFA should be based on
907 * @return new DFA state
909 static struct GNUNET_REGEX_State *
910 dfa_state_create (struct GNUNET_REGEX_Context *ctx,
911 struct GNUNET_REGEX_StateSet *nfa_states)
913 struct GNUNET_REGEX_State *s;
916 struct GNUNET_REGEX_State *cstate;
917 struct Transition *ctran;
919 struct Transition *t;
922 s = GNUNET_malloc (sizeof (struct GNUNET_REGEX_State));
923 s->id = ctx->state_id++;
933 if (NULL == nfa_states)
935 GNUNET_asprintf (&s->name, "s%i", s->id);
939 s->nfa_set = nfa_states;
941 if (nfa_states->len < 1)
944 // Create a name based on 'sset'
945 s->name = GNUNET_malloc (sizeof (char) * 2);
946 strcat (s->name, "{");
949 for (i = 0; i < nfa_states->len; i++)
951 cstate = nfa_states->states[i];
952 GNUNET_asprintf (&name, "%i,", cstate->id);
956 len = strlen (s->name) + strlen (name) + 1;
957 s->name = GNUNET_realloc (s->name, len);
958 strcat (s->name, name);
963 // Add a transition for each distinct label to NULL state
964 for (ctran = cstate->transitions_head; NULL != ctran; ctran = ctran->next)
966 if (0 != ctran->label)
970 for (t = s->transitions_head; NULL != t; t = t->next)
972 if (t->label == ctran->label)
980 state_add_transition (ctx, s, ctran->label, NULL);
984 // If the nfa_states contain an accepting state, the new dfa state is also
986 if (cstate->accepting)
990 s->name[strlen (s->name) - 1] = '}';
996 * Move from the given state 's' to the next state on transition 'label'
998 * @param s starting state
999 * @param label edge label to follow
1001 * @return new state or NULL, if transition on label not possible
1003 static struct GNUNET_REGEX_State *
1004 dfa_move (struct GNUNET_REGEX_State *s, const char label)
1006 struct Transition *t;
1007 struct GNUNET_REGEX_State *new_s;
1014 for (t = s->transitions_head; NULL != t; t = t->next)
1016 if (label == t->label)
1018 new_s = t->to_state;
1027 * Remove all unreachable states from DFA 'a'. Unreachable states are those
1028 * states that are not reachable from the starting state.
1030 * @param a DFA automaton
1033 dfa_remove_unreachable_states (struct GNUNET_REGEX_Automaton *a)
1035 struct GNUNET_REGEX_State *s;
1036 struct GNUNET_REGEX_State *s_next;
1038 // 1. unmark all states
1039 for (s = a->states_head; NULL != s; s = s->next)
1040 s->marked = GNUNET_NO;
1042 // 2. traverse dfa from start state and mark all visited states
1043 automaton_traverse (NULL, a, NULL);
1045 // 3. delete all states that were not visited
1046 for (s = a->states_head; NULL != s; s = s_next)
1049 if (GNUNET_NO == s->marked)
1050 automaton_remove_state (a, s);
1055 * Remove all dead states from the DFA 'a'. Dead states are those states that do
1056 * not transition to any other state but themselfes.
1058 * @param a DFA automaton
1061 dfa_remove_dead_states (struct GNUNET_REGEX_Automaton *a)
1063 struct GNUNET_REGEX_State *s;
1064 struct Transition *t;
1067 GNUNET_assert (DFA == a->type);
1069 for (s = a->states_head; NULL != s; s = s->next)
1075 for (t = s->transitions_head; NULL != t; t = t->next)
1077 if (NULL != t->to_state && t->to_state != s)
1087 // state s is dead, remove it
1088 automaton_remove_state (a, s);
1093 * Merge all non distinguishable states in the DFA 'a'
1095 * @param ctx context
1096 * @param a DFA automaton
1099 dfa_merge_nondistinguishable_states (struct GNUNET_REGEX_Context *ctx,
1100 struct GNUNET_REGEX_Automaton *a)
1103 int table[a->state_count][a->state_count];
1104 struct GNUNET_REGEX_State *s1;
1105 struct GNUNET_REGEX_State *s2;
1106 struct Transition *t1;
1107 struct Transition *t2;
1108 struct GNUNET_REGEX_State *s1_next;
1109 struct GNUNET_REGEX_State *s2_next;
1111 int num_equal_edges;
1113 for (i = 0, s1 = a->states_head; i < a->state_count && NULL != s1;
1119 // Mark all pairs of accepting/!accepting states
1120 for (s1 = a->states_head; NULL != s1; s1 = s1->next)
1122 for (s2 = a->states_head; NULL != s2; s2 = s2->next)
1124 table[s1->marked][s2->marked] = 0;
1126 if ((s1->accepting && !s2->accepting) ||
1127 (!s1->accepting && s2->accepting))
1129 table[s1->marked][s2->marked] = 1;
1134 // Find all equal states
1139 for (s1 = a->states_head; NULL != s1; s1 = s1->next)
1141 for (s2 = a->states_head; NULL != s2 && s1 != s2; s2 = s2->next)
1143 if (0 != table[s1->marked][s2->marked])
1146 num_equal_edges = 0;
1147 for (t1 = s1->transitions_head; NULL != t1; t1 = t1->next)
1149 for (t2 = s2->transitions_head; NULL != t2; t2 = t2->next)
1151 if (t1->label == t2->label)
1154 if (0 != table[t1->to_state->marked][t2->to_state->marked] ||
1155 0 != table[t2->to_state->marked][t1->to_state->marked])
1157 table[s1->marked][s2->marked] = t1->label != 0 ? t1->label : 1;
1163 if (num_equal_edges != s1->transition_count ||
1164 num_equal_edges != s2->transition_count)
1166 // Make sure ALL edges of possible equal states are the same
1167 table[s1->marked][s2->marked] = -2;
1173 // Merge states that are equal
1174 for (s1 = a->states_head; NULL != s1; s1 = s1_next)
1177 for (s2 = a->states_head; NULL != s2 && s1 != s2; s2 = s2_next)
1180 if (table[s1->marked][s2->marked] == 0)
1181 automaton_merge_states (ctx, a, s1, s2);
1187 * Minimize the given DFA 'a' by removing all unreachable states, removing all
1188 * dead states and merging all non distinguishable states
1190 * @param ctx context
1191 * @param a DFA automaton
1194 dfa_minimize (struct GNUNET_REGEX_Context *ctx,
1195 struct GNUNET_REGEX_Automaton *a)
1200 GNUNET_assert (DFA == a->type);
1202 // 1. remove unreachable states
1203 dfa_remove_unreachable_states (a);
1205 // 2. remove dead states
1206 dfa_remove_dead_states (a);
1208 // 3. Merge nondistinguishable states
1209 dfa_merge_nondistinguishable_states (ctx, a);
1213 * Creates a new NFA fragment. Needs to be cleared using
1214 * automaton_fragment_clear.
1216 * @param start starting state
1217 * @param end end state
1219 * @return new NFA fragment
1221 static struct GNUNET_REGEX_Automaton *
1222 nfa_fragment_create (struct GNUNET_REGEX_State *start,
1223 struct GNUNET_REGEX_State *end)
1225 struct GNUNET_REGEX_Automaton *n;
1227 n = GNUNET_malloc (sizeof (struct GNUNET_REGEX_Automaton));
1233 if (NULL == start && NULL == end)
1236 automaton_add_state (n, end);
1237 automaton_add_state (n, start);
1246 * Adds a list of states to the given automaton 'n'.
1248 * @param n automaton to which the states should be added
1249 * @param states_head head of the DLL of states
1250 * @param states_tail tail of the DLL of states
1253 nfa_add_states (struct GNUNET_REGEX_Automaton *n,
1254 struct GNUNET_REGEX_State *states_head,
1255 struct GNUNET_REGEX_State *states_tail)
1257 struct GNUNET_REGEX_State *s;
1259 if (NULL == n || NULL == states_head)
1261 GNUNET_log (GNUNET_ERROR_TYPE_ERROR, "Could not add states\n");
1265 if (NULL == n->states_head)
1267 n->states_head = states_head;
1268 n->states_tail = states_tail;
1272 if (NULL != states_head)
1274 n->states_tail->next = states_head;
1275 n->states_tail = states_tail;
1278 for (s = states_head; NULL != s; s = s->next)
1283 * Creates a new NFA state. Needs to be freed using automaton_destroy_state.
1285 * @param ctx context
1286 * @param accepting is it an accepting state or not
1288 * @return new NFA state
1290 static struct GNUNET_REGEX_State *
1291 nfa_state_create (struct GNUNET_REGEX_Context *ctx, int accepting)
1293 struct GNUNET_REGEX_State *s;
1295 s = GNUNET_malloc (sizeof (struct GNUNET_REGEX_State));
1296 s->id = ctx->state_id++;
1297 s->accepting = accepting;
1304 GNUNET_asprintf (&s->name, "s%i", s->id);
1310 * Calculates the NFA closure set for the given state.
1312 * @param nfa the NFA containing 's'
1313 * @param s starting point state
1314 * @param label transitioning label on which to base the closure on,
1315 * pass 0 for epsilon transition
1317 * @return sorted nfa closure on 'label' (epsilon closure if 'label' is 0)
1319 static struct GNUNET_REGEX_StateSet *
1320 nfa_closure_create (struct GNUNET_REGEX_Automaton *nfa,
1321 struct GNUNET_REGEX_State *s, const char label)
1323 struct GNUNET_REGEX_StateSet *cls;
1324 struct GNUNET_REGEX_StateSet *cls_check;
1325 struct GNUNET_REGEX_State *clsstate;
1326 struct GNUNET_REGEX_State *currentstate;
1327 struct Transition *ctran;
1332 cls = GNUNET_malloc (sizeof (struct GNUNET_REGEX_StateSet));
1333 cls_check = GNUNET_malloc (sizeof (struct GNUNET_REGEX_StateSet));
1335 for (clsstate = nfa->states_head; NULL != clsstate; clsstate = clsstate->next)
1336 clsstate->contained = 0;
1338 // Add start state to closure only for epsilon closure
1340 GNUNET_array_append (cls->states, cls->len, s);
1342 GNUNET_array_append (cls_check->states, cls_check->len, s);
1343 while (cls_check->len > 0)
1345 currentstate = cls_check->states[cls_check->len - 1];
1346 GNUNET_array_grow (cls_check->states, cls_check->len, cls_check->len - 1);
1348 for (ctran = currentstate->transitions_head; NULL != ctran;
1349 ctran = ctran->next)
1351 if (NULL != ctran->to_state && label == ctran->label)
1353 clsstate = ctran->to_state;
1355 if (NULL != clsstate && 0 == clsstate->contained)
1357 GNUNET_array_append (cls->states, cls->len, clsstate);
1358 GNUNET_array_append (cls_check->states, cls_check->len, clsstate);
1359 clsstate->contained = 1;
1364 GNUNET_assert (0 == cls_check->len);
1365 GNUNET_free (cls_check);
1368 qsort (cls->states, cls->len, sizeof (struct GNUNET_REGEX_State *),
1375 * Calculates the closure set for the given set of states.
1377 * @param nfa the NFA containing 's'
1378 * @param states list of states on which to base the closure on
1379 * @param label transitioning label for which to base the closure on,
1380 * pass 0 for epsilon transition
1382 * @return sorted nfa closure on 'label' (epsilon closure if 'label' is 0)
1384 static struct GNUNET_REGEX_StateSet *
1385 nfa_closure_set_create (struct GNUNET_REGEX_Automaton *nfa,
1386 struct GNUNET_REGEX_StateSet *states, const char label)
1388 struct GNUNET_REGEX_State *s;
1389 struct GNUNET_REGEX_StateSet *sset;
1390 struct GNUNET_REGEX_StateSet *cls;
1399 cls = GNUNET_malloc (sizeof (struct GNUNET_REGEX_StateSet));
1401 for (i = 0; i < states->len; i++)
1403 s = states->states[i];
1404 sset = nfa_closure_create (nfa, s, label);
1406 for (j = 0; j < sset->len; j++)
1409 for (k = 0; k < cls->len; k++)
1411 if (sset->states[j]->id == cls->states[k]->id)
1418 GNUNET_array_append (cls->states, cls->len, sset->states[j]);
1420 state_set_clear (sset);
1424 qsort (cls->states, cls->len, sizeof (struct GNUNET_REGEX_State *),
1431 * Pops two NFA fragments (a, b) from the stack and concatenates them (ab)
1433 * @param ctx context
1436 nfa_add_concatenation (struct GNUNET_REGEX_Context *ctx)
1438 struct GNUNET_REGEX_Automaton *a;
1439 struct GNUNET_REGEX_Automaton *b;
1440 struct GNUNET_REGEX_Automaton *new;
1442 b = ctx->stack_tail;
1443 GNUNET_CONTAINER_DLL_remove (ctx->stack_head, ctx->stack_tail, b);
1444 a = ctx->stack_tail;
1445 GNUNET_CONTAINER_DLL_remove (ctx->stack_head, ctx->stack_tail, a);
1447 state_add_transition (ctx, a->end, 0, b->start);
1448 a->end->accepting = 0;
1449 b->end->accepting = 1;
1451 new = nfa_fragment_create (NULL, NULL);
1452 nfa_add_states (new, a->states_head, a->states_tail);
1453 nfa_add_states (new, b->states_head, b->states_tail);
1454 new->start = a->start;
1456 automaton_fragment_clear (a);
1457 automaton_fragment_clear (b);
1459 GNUNET_CONTAINER_DLL_insert_tail (ctx->stack_head, ctx->stack_tail, new);
1463 * Pops a NFA fragment from the stack (a) and adds a new fragment (a*)
1465 * @param ctx context
1468 nfa_add_star_op (struct GNUNET_REGEX_Context *ctx)
1470 struct GNUNET_REGEX_Automaton *a;
1471 struct GNUNET_REGEX_Automaton *new;
1472 struct GNUNET_REGEX_State *start;
1473 struct GNUNET_REGEX_State *end;
1475 a = ctx->stack_tail;
1476 GNUNET_CONTAINER_DLL_remove (ctx->stack_head, ctx->stack_tail, a);
1480 GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
1481 "nfa_add_star_op failed, because there was no element on the stack");
1485 start = nfa_state_create (ctx, 0);
1486 end = nfa_state_create (ctx, 1);
1488 state_add_transition (ctx, start, 0, a->start);
1489 state_add_transition (ctx, start, 0, end);
1490 state_add_transition (ctx, a->end, 0, a->start);
1491 state_add_transition (ctx, a->end, 0, end);
1493 a->end->accepting = 0;
1496 new = nfa_fragment_create (start, end);
1497 nfa_add_states (new, a->states_head, a->states_tail);
1498 automaton_fragment_clear (a);
1500 GNUNET_CONTAINER_DLL_insert_tail (ctx->stack_head, ctx->stack_tail, new);
1504 * Pops an NFA fragment (a) from the stack and adds a new fragment (a+)
1506 * @param ctx context
1509 nfa_add_plus_op (struct GNUNET_REGEX_Context *ctx)
1511 struct GNUNET_REGEX_Automaton *a;
1513 a = ctx->stack_tail;
1514 GNUNET_CONTAINER_DLL_remove (ctx->stack_head, ctx->stack_tail, a);
1516 state_add_transition (ctx, a->end, 0, a->start);
1518 GNUNET_CONTAINER_DLL_insert_tail (ctx->stack_head, ctx->stack_tail, a);
1522 * Pops an NFA fragment (a) from the stack and adds a new fragment (a?)
1524 * @param ctx context
1527 nfa_add_question_op (struct GNUNET_REGEX_Context *ctx)
1529 struct GNUNET_REGEX_Automaton *a;
1530 struct GNUNET_REGEX_Automaton *new;
1531 struct GNUNET_REGEX_State *start;
1532 struct GNUNET_REGEX_State *end;
1534 a = ctx->stack_tail;
1535 GNUNET_CONTAINER_DLL_remove (ctx->stack_head, ctx->stack_tail, a);
1539 GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
1540 "nfa_add_question_op failed, because there was no element on the stack");
1544 start = nfa_state_create (ctx, 0);
1545 end = nfa_state_create (ctx, 1);
1547 state_add_transition (ctx, start, 0, a->start);
1548 state_add_transition (ctx, start, 0, end);
1549 state_add_transition (ctx, a->end, 0, end);
1551 a->end->accepting = 0;
1553 new = nfa_fragment_create (start, end);
1554 nfa_add_states (new, a->states_head, a->states_tail);
1555 automaton_fragment_clear (a);
1557 GNUNET_CONTAINER_DLL_insert_tail (ctx->stack_head, ctx->stack_tail, new);
1561 * Pops two NFA fragments (a, b) from the stack and adds a new NFA fragment that
1562 * alternates between a and b (a|b)
1564 * @param ctx context
1567 nfa_add_alternation (struct GNUNET_REGEX_Context *ctx)
1569 struct GNUNET_REGEX_Automaton *a;
1570 struct GNUNET_REGEX_Automaton *b;
1571 struct GNUNET_REGEX_Automaton *new;
1572 struct GNUNET_REGEX_State *start;
1573 struct GNUNET_REGEX_State *end;
1575 b = ctx->stack_tail;
1576 GNUNET_CONTAINER_DLL_remove (ctx->stack_head, ctx->stack_tail, b);
1577 a = ctx->stack_tail;
1578 GNUNET_CONTAINER_DLL_remove (ctx->stack_head, ctx->stack_tail, a);
1580 start = nfa_state_create (ctx, 0);
1581 end = nfa_state_create (ctx, 1);
1582 state_add_transition (ctx, start, 0, a->start);
1583 state_add_transition (ctx, start, 0, b->start);
1585 state_add_transition (ctx, a->end, 0, end);
1586 state_add_transition (ctx, b->end, 0, end);
1588 a->end->accepting = 0;
1589 b->end->accepting = 0;
1592 new = nfa_fragment_create (start, end);
1593 nfa_add_states (new, a->states_head, a->states_tail);
1594 nfa_add_states (new, b->states_head, b->states_tail);
1595 automaton_fragment_clear (a);
1596 automaton_fragment_clear (b);
1598 GNUNET_CONTAINER_DLL_insert_tail (ctx->stack_head, ctx->stack_tail, new);
1602 * Adds a new nfa fragment to the stack
1604 * @param ctx context
1605 * @param lit label for nfa transition
1608 nfa_add_label (struct GNUNET_REGEX_Context *ctx, const char lit)
1610 struct GNUNET_REGEX_Automaton *n;
1611 struct GNUNET_REGEX_State *start;
1612 struct GNUNET_REGEX_State *end;
1614 GNUNET_assert (NULL != ctx);
1616 start = nfa_state_create (ctx, 0);
1617 end = nfa_state_create (ctx, 1);
1618 state_add_transition (ctx, start, lit, end);
1619 n = nfa_fragment_create (start, end);
1620 GNUNET_assert (NULL != n);
1621 GNUNET_CONTAINER_DLL_insert_tail (ctx->stack_head, ctx->stack_tail, n);
1625 * Initialize a new context
1627 * @param ctx context
1630 GNUNET_REGEX_context_init (struct GNUNET_REGEX_Context *ctx)
1634 GNUNET_log (GNUNET_ERROR_TYPE_ERROR, "Context was NULL!");
1638 ctx->transition_id = 0;
1640 ctx->stack_head = NULL;
1641 ctx->stack_tail = NULL;
1645 * Construct an NFA by parsing the regex string of length 'len'.
1647 * @param regex regular expression string
1648 * @param len length of the string
1650 * @return NFA, needs to be freed using GNUNET_REGEX_destroy_automaton
1652 struct GNUNET_REGEX_Automaton *
1653 GNUNET_REGEX_construct_nfa (const char *regex, const size_t len)
1655 struct GNUNET_REGEX_Context ctx;
1656 struct GNUNET_REGEX_Automaton *nfa;
1660 unsigned int altcount;
1661 unsigned int atomcount;
1662 unsigned int pcount;
1669 GNUNET_REGEX_context_init (&ctx);
1678 for (count = 0; count < len && *regexp; count++, regexp++)
1686 nfa_add_concatenation (&ctx);
1688 GNUNET_array_grow (p, pcount, pcount + 1);
1689 p[pcount - 1].altcount = altcount;
1690 p[pcount - 1].atomcount = atomcount;
1697 error_msg = "Cannot append '|' to nothing";
1700 while (--atomcount > 0)
1701 nfa_add_concatenation (&ctx);
1707 error_msg = "Missing opening '('";
1712 // Ignore this: "()"
1714 altcount = p[pcount].altcount;
1715 atomcount = p[pcount].atomcount;
1718 while (--atomcount > 0)
1719 nfa_add_concatenation (&ctx);
1720 for (; altcount > 0; altcount--)
1721 nfa_add_alternation (&ctx);
1723 altcount = p[pcount].altcount;
1724 atomcount = p[pcount].atomcount;
1730 error_msg = "Cannot append '*' to nothing";
1733 nfa_add_star_op (&ctx);
1738 error_msg = "Cannot append '+' to nothing";
1741 nfa_add_plus_op (&ctx);
1746 error_msg = "Cannot append '?' to nothing";
1749 nfa_add_question_op (&ctx);
1751 case 92: /* escape: \ */
1758 nfa_add_concatenation (&ctx);
1760 nfa_add_label (&ctx, *regexp);
1767 error_msg = "Unbalanced parenthesis";
1770 while (--atomcount > 0)
1771 nfa_add_concatenation (&ctx);
1772 for (; altcount > 0; altcount--)
1773 nfa_add_alternation (&ctx);
1778 nfa = ctx.stack_tail;
1779 GNUNET_CONTAINER_DLL_remove (ctx.stack_head, ctx.stack_tail, nfa);
1781 if (NULL != ctx.stack_head)
1783 error_msg = "Creating the NFA failed. NFA stack was not empty!";
1790 GNUNET_log (GNUNET_ERROR_TYPE_ERROR, "Could not parse regex\n");
1791 if (NULL != error_msg)
1792 GNUNET_log (GNUNET_ERROR_TYPE_ERROR, "%s\n", error_msg);
1795 while (NULL != ctx.stack_tail)
1797 GNUNET_REGEX_automaton_destroy (ctx.stack_tail);
1798 GNUNET_CONTAINER_DLL_remove (ctx.stack_head, ctx.stack_tail,
1805 * Create DFA states based on given 'nfa' and starting with 'dfa_state'.
1807 * @param ctx context.
1808 * @param nfa NFA automaton.
1809 * @param dfa DFA automaton.
1810 * @param dfa_state current dfa state, pass epsilon closure of first nfa state
1814 construct_dfa_states (struct GNUNET_REGEX_Context *ctx,
1815 struct GNUNET_REGEX_Automaton *nfa,
1816 struct GNUNET_REGEX_Automaton *dfa,
1817 struct GNUNET_REGEX_State *dfa_state)
1819 struct Transition *ctran;
1820 struct GNUNET_REGEX_State *state_iter;
1821 struct GNUNET_REGEX_State *new_dfa_state;
1822 struct GNUNET_REGEX_State *state_contains;
1823 struct GNUNET_REGEX_StateSet *tmp;
1824 struct GNUNET_REGEX_StateSet *nfa_set;
1826 for (ctran = dfa_state->transitions_head; NULL != ctran; ctran = ctran->next)
1828 if (0 == ctran->label || NULL != ctran->to_state)
1831 tmp = nfa_closure_set_create (nfa, dfa_state->nfa_set, ctran->label);
1832 nfa_set = nfa_closure_set_create (nfa, tmp, 0);
1833 state_set_clear (tmp);
1834 new_dfa_state = dfa_state_create (ctx, nfa_set);
1835 state_contains = NULL;
1836 for (state_iter = dfa->states_head; NULL != state_iter;
1837 state_iter = state_iter->next)
1839 if (0 == state_set_compare (state_iter->nfa_set, new_dfa_state->nfa_set))
1840 state_contains = state_iter;
1843 if (NULL == state_contains)
1845 automaton_add_state (dfa, new_dfa_state);
1846 ctran->to_state = new_dfa_state;
1847 construct_dfa_states (ctx, nfa, dfa, new_dfa_state);
1851 ctran->to_state = state_contains;
1852 automaton_destroy_state (new_dfa_state);
1858 * Construct DFA for the given 'regex' of length 'len'
1860 * @param regex regular expression string
1861 * @param len length of the regular expression
1863 * @return DFA, needs to be freed using GNUNET_REGEX_destroy_automaton
1865 struct GNUNET_REGEX_Automaton *
1866 GNUNET_REGEX_construct_dfa (const char *regex, const size_t len)
1868 struct GNUNET_REGEX_Context ctx;
1869 struct GNUNET_REGEX_Automaton *dfa;
1870 struct GNUNET_REGEX_Automaton *nfa;
1871 struct GNUNET_REGEX_StateSet *nfa_set;
1873 GNUNET_REGEX_context_init (&ctx);
1876 nfa = GNUNET_REGEX_construct_nfa (regex, len);
1880 GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
1881 "Could not create DFA, because NFA creation failed\n");
1885 dfa = GNUNET_malloc (sizeof (struct GNUNET_REGEX_Automaton));
1888 // Create DFA start state from epsilon closure
1889 nfa_set = nfa_closure_create (nfa, nfa->start, 0);
1890 dfa->start = dfa_state_create (&ctx, nfa_set);
1891 automaton_add_state (dfa, dfa->start);
1893 construct_dfa_states (&ctx, nfa, dfa, dfa->start);
1895 GNUNET_REGEX_automaton_destroy (nfa);
1898 dfa_minimize (&ctx, dfa);
1901 scc_tarjan (&ctx, dfa);
1903 // Create proofs for all states
1904 automaton_create_proofs (dfa);
1910 * Free the memory allocated by constructing the GNUNET_REGEX_Automaton data
1913 * @param a automaton to be destroyed
1916 GNUNET_REGEX_automaton_destroy (struct GNUNET_REGEX_Automaton *a)
1918 struct GNUNET_REGEX_State *s;
1919 struct GNUNET_REGEX_State *next_state;
1924 for (s = a->states_head; NULL != s;)
1926 next_state = s->next;
1927 automaton_destroy_state (s);
1935 * Save the given automaton as a GraphViz dot file
1937 * @param a the automaton to be saved
1938 * @param filename where to save the file
1941 GNUNET_REGEX_automaton_save_graph (struct GNUNET_REGEX_Automaton *a,
1942 const char *filename)
1944 struct GNUNET_REGEX_State *s;
1945 struct Transition *ctran;
1947 char *s_tran = NULL;
1954 GNUNET_log (GNUNET_ERROR_TYPE_ERROR, "Could not print NFA, was NULL!");
1958 if (NULL == filename || strlen (filename) < 1)
1960 GNUNET_log (GNUNET_ERROR_TYPE_ERROR, "No Filename given!");
1964 p = fopen (filename, "w");
1968 GNUNET_log (GNUNET_ERROR_TYPE_ERROR, "Could not open file for writing: %s",
1973 start = "digraph G {\nrankdir=LR\n";
1974 fwrite (start, strlen (start), 1, p);
1976 for (s = a->states_head; NULL != s; s = s->next)
1980 GNUNET_asprintf (&s_acc,
1981 "\"%s\" [shape=doublecircle, color=\"0.%i 0.8 0.95\"];\n",
1982 s->name, s->scc_id);
1986 GNUNET_asprintf (&s_acc, "\"%s\" [color=\"0.%i 0.8 0.95\"];\n", s->name,
1992 GNUNET_log (GNUNET_ERROR_TYPE_ERROR, "Could not print state %s\n",
1996 fwrite (s_acc, strlen (s_acc), 1, p);
1997 GNUNET_free (s_acc);
2000 for (ctran = s->transitions_head; NULL != ctran; ctran = ctran->next)
2002 if (NULL == ctran->to_state)
2004 GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
2005 "Transition from State %i has has no state for transitioning\n",
2010 if (ctran->label == 0)
2012 GNUNET_asprintf (&s_tran,
2013 "\"%s\" -> \"%s\" [label = \"epsilon\", color=\"0.%i 0.8 0.95\"];\n",
2014 s->name, ctran->to_state->name, s->scc_id);
2018 GNUNET_asprintf (&s_tran,
2019 "\"%s\" -> \"%s\" [label = \"%c\", color=\"0.%i 0.8 0.95\"];\n",
2020 s->name, ctran->to_state->name, ctran->label,
2026 GNUNET_log (GNUNET_ERROR_TYPE_ERROR, "Could not print state %s\n",
2031 fwrite (s_tran, strlen (s_tran), 1, p);
2032 GNUNET_free (s_tran);
2038 fwrite (end, strlen (end), 1, p);
2043 * Evaluates the given string using the given DFA automaton
2045 * @param a automaton, type must be DFA
2046 * @param string string that should be evaluated
2048 * @return 0 if string matches, non 0 otherwise
2051 evaluate_dfa (struct GNUNET_REGEX_Automaton *a, const char *string)
2054 struct GNUNET_REGEX_State *s;
2058 GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
2059 "Tried to evaluate DFA, but NFA automaton given");
2065 for (strp = string; NULL != strp && *strp; strp++)
2067 s = dfa_move (s, *strp);
2072 if (NULL != s && s->accepting)
2079 * Evaluates the given string using the given NFA automaton
2081 * @param a automaton, type must be NFA
2082 * @param string string that should be evaluated
2084 * @return 0 if string matches, non 0 otherwise
2087 evaluate_nfa (struct GNUNET_REGEX_Automaton *a, const char *string)
2090 struct GNUNET_REGEX_State *s;
2091 struct GNUNET_REGEX_StateSet *sset;
2092 struct GNUNET_REGEX_StateSet *new_sset;
2098 GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
2099 "Tried to evaluate NFA, but DFA automaton given");
2105 sset = nfa_closure_create (a, a->start, 0);
2107 for (strp = string; NULL != strp && *strp; strp++)
2109 new_sset = nfa_closure_set_create (a, sset, *strp);
2110 state_set_clear (sset);
2111 sset = nfa_closure_set_create (a, new_sset, 0);
2112 state_set_clear (new_sset);
2115 for (i = 0; i < sset->len; i++)
2117 s = sset->states[i];
2118 if (NULL != s && s->accepting)
2125 state_set_clear (sset);
2130 * Evaluates the given 'string' against the given compiled regex
2132 * @param a automaton
2133 * @param string string to check
2135 * @return 0 if string matches, non 0 otherwise
2138 GNUNET_REGEX_eval (struct GNUNET_REGEX_Automaton *a, const char *string)
2145 result = evaluate_dfa (a, string);
2148 result = evaluate_nfa (a, string);
2151 GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
2152 "Evaluating regex failed, automaton has no type!\n");
2153 result = GNUNET_SYSERR;
2161 * Get the first key for the given 'input_string'. This hashes the first x bits
2162 * of the 'input_strings'.
2164 * @param input_string string.
2165 * @param string_len length of the 'input_string'.
2166 * @param key pointer to where to write the hash code.
2168 * @return number of bits of 'input_string' that have been consumed
2169 * to construct the key
2172 GNUNET_REGEX_get_first_key (const char *input_string, unsigned int string_len,
2173 GNUNET_HashCode * key)
2177 size = string_len < initial_bits ? string_len : initial_bits;
2179 if (NULL == input_string)
2181 GNUNET_log (GNUNET_ERROR_TYPE_ERROR, "Given input string was NULL!\n");
2185 GNUNET_CRYPTO_hash (input_string, size, key);
2191 * Check if the given 'proof' matches the given 'key'.
2193 * @param proof partial regex
2196 * @return GNUNET_OK if the proof is valid for the given key
2199 GNUNET_REGEX_check_proof (const char *proof, const GNUNET_HashCode * key)
2205 * Iterate over all edges helper function starting from state 's', calling
2206 * iterator on for each edge.
2209 * @param iterator iterator function called for each edge.
2210 * @param iterator_cls closure.
2213 iterate_edge (struct GNUNET_REGEX_State *s, GNUNET_REGEX_KeyIterator iterator,
2216 struct Transition *t;
2217 struct GNUNET_REGEX_Edge edges[s->transition_count];
2218 unsigned int num_edges;
2220 if (GNUNET_YES != s->marked)
2222 s->marked = GNUNET_YES;
2224 num_edges = state_get_edges (s, edges);
2226 iterator (iterator_cls, &s->hash, s->proof, s->accepting, num_edges, edges);
2228 for (t = s->transitions_head; NULL != t; t = t->next)
2229 iterate_edge (t->to_state, iterator, iterator_cls);
2234 * Iterate over all edges starting from start state of automaton 'a'. Calling
2235 * iterator for each edge.
2237 * @param a automaton.
2238 * @param iterator iterator called for each edge.
2239 * @param iterator_cls closure.
2242 GNUNET_REGEX_iterate_all_edges (struct GNUNET_REGEX_Automaton *a,
2243 GNUNET_REGEX_KeyIterator iterator,
2246 struct GNUNET_REGEX_State *s;
2248 for (s = a->states_head; NULL != s; s = s->next)
2249 s->marked = GNUNET_NO;
2251 iterate_edge (a->start, iterator, iterator_cls);