#include "gnunet_regex_lib.h"
#include "regex.h"
-void
-stack_push (struct GNUNET_CONTAINER_SList *stack, const void *buf, size_t len)
+/**
+ * Context that contains an id counter for states and transitions
+ * as well as a DLL of automatons used as a stack for NFA construction.
+ */
+struct GNUNET_REGEX_Context
{
- GNUNET_CONTAINER_slist_add (stack, GNUNET_CONTAINER_SLIST_DISPOSITION_STATIC,
- buf, len);
-}
+ /**
+ * Unique state id.
+ */
+ unsigned int state_id;
-int
-stack_empty (struct GNUNET_CONTAINER_SList *stack)
-{
- return 0 == GNUNET_CONTAINER_slist_count (stack);
-}
+ /**
+ * Unique transition id.
+ */
+ unsigned int transition_id;
-void *
-stack_pop (struct GNUNET_CONTAINER_SList *stack, size_t length)
-{
- struct GNUNET_CONTAINER_SList_Iterator it;
- void *val;
- size_t len;
+ /**
+ * DLL of GNUNET_REGEX_Automaton's used as a stack.
+ */
+ struct GNUNET_REGEX_Automaton *stack_head;
- it = GNUNET_CONTAINER_slist_begin (stack);
- val = GNUNET_CONTAINER_slist_get (&it, &len);
- GNUNET_assert (length == len);
- GNUNET_CONTAINER_slist_erase (&it);
- GNUNET_CONTAINER_slist_iter_destroy (&it);
+ /**
+ * DLL of GNUNET_REGEX_Automaton's used as a stack.
+ */
+ struct GNUNET_REGEX_Automaton *stack_tail;
+};
- return val;
-}
+/**
+ * Type of an automaton.
+ */
+enum GNUNET_REGEX_automaton_type
+{
+ NFA,
+ DFA
+};
-void *
-stack_top (struct GNUNET_CONTAINER_SList *stack, size_t *len)
+/**
+ * Automaton representation.
+ */
+struct GNUNET_REGEX_Automaton
{
- struct GNUNET_CONTAINER_SList_Iterator it;
+ /**
+ * This is a linked list.
+ */
+ struct GNUNET_REGEX_Automaton *prev;
+
+ /**
+ * This is a linked list.
+ */
+ struct GNUNET_REGEX_Automaton *next;
+
+ /**
+ * First state of the automaton. This is mainly
+ * used for constructing an NFA, where each NFA
+ * itself consists of one or more NFAs linked
+ * together.
+ */
+ struct State *start;
- if (stack_empty (stack))
- return NULL;
+ /**
+ * End state of the automaton.
+ */
+ struct State *end;
- return GNUNET_CONTAINER_slist_get (&it, len);
-}
+ /**
+ * Number of states in the automaton.
+ */
+ unsigned int state_count;
+
+ /**
+ * DLL of states.
+ */
+ struct State *states_head;
+
+ /**
+ * DLL of states
+ */
+ struct State *states_tail;
+
+ /**
+ * Type of the automaton.
+ */
+ enum GNUNET_REGEX_automaton_type type;
+};
+/**
+ * A state. Can be used in DFA and NFA automatons.
+ */
struct State
{
+ /**
+ * This is a linked list.
+ */
+ struct State *prev;
+
+ /**
+ * This is a linked list.
+ */
+ struct State *next;
+
+ /**
+ * Unique state id.
+ */
unsigned int id;
+
+ /**
+ * If this is an accepting state or not.
+ */
int accepting;
+
+ /**
+ * Marking of the state. This is used for marking all visited
+ * states when traversing all states of an automaton and for
+ * cases where the state id cannot be used (dfa minimization).
+ */
int marked;
+
+ /**
+ * Human readable name of the automaton. Used for debugging
+ * and graph creation.
+ */
char *name;
- struct GNUNET_CONTAINER_SList *transitions;
- struct GNUNET_CONTAINER_SList *nfa_set;
-};
-struct GNUNET_REGEX_Automaton
-{
- struct State *start;
- struct State *end;
- struct GNUNET_CONTAINER_SList *states;
+ /**
+ * Number of transitions from this state to other states.
+ */
+ unsigned int transition_count;
+
+ /**
+ * DLL of transitions.
+ */
+ struct Transition *transitions_head;
+
+ /**
+ * DLL of transitions.
+ */
+ struct Transition *transitions_tail;
+
+ /**
+ * Set of states on which this state is based on. Used when
+ * creating a DFA out of several NFA states.
+ */
+ struct StateSet *nfa_set;
};
+/**
+ * Transition between two states. Each state can have 0-n transitions.
+ * If literal is 0, this is considered to be an epsilon transition.
+ */
struct Transition
{
+ /**
+ * This is a linked list.
+ */
+ struct Transition *prev;
+
+ /**
+ * This is a linked list.
+ */
+ struct Transition *next;
+
+ /**
+ * Unique id of this transition.
+ */
unsigned int id;
+
+ /**
+ * Literal for this transition. This is basically the edge label for
+ * the graph.
+ */
char literal;
+
+ /**
+ * State to which this transition leads.
+ */
struct State *state;
};
-struct GNUNET_REGEX_Context
+/**
+ * Set of states.
+ */
+struct StateSet
{
- unsigned int state_id;
- unsigned int transition_id;
- struct GNUNET_CONTAINER_SList *stack;
+ /**
+ * Array of states.
+ */
+ struct State **states;
+
+ /**
+ * Length of the 'states' array.
+ */
+ unsigned int len;
};
-void
+/**
+ * Initialize a new context
+ *
+ * @param ctx context
+ */
+static void
GNUNET_REGEX_context_init (struct GNUNET_REGEX_Context *ctx)
{
if (NULL == ctx)
}
ctx->state_id = 0;
ctx->transition_id = 0;
- ctx->stack = GNUNET_CONTAINER_slist_create();
-}
-
-void
-GNUNET_REGEX_context_destroy (struct GNUNET_REGEX_Context *ctx)
-{
- if (NULL != ctx->stack)
- GNUNET_CONTAINER_slist_destroy(ctx->stack);
+ ctx->stack_head = NULL;
+ ctx->stack_tail = NULL;
}
-void
+static void
debug_print_state (struct State *s)
{
- GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "State %i: %s marked: %i accepting: %i\n",
- s->id, s->name, s->marked, s->accepting);
+ GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+ "State %i: %s marked: %i accepting: %i\n", s->id, s->name,
+ s->marked, s->accepting);
}
-void
-debug_print_states (struct GNUNET_CONTAINER_SList *states)
+static void
+debug_print_states (struct StateSet *sset)
{
- struct GNUNET_CONTAINER_SList_Iterator it;
struct State *s;
+ int i;
- for (it = GNUNET_CONTAINER_slist_begin (states);
- GNUNET_YES != GNUNET_CONTAINER_slist_end (&it);
- GNUNET_CONTAINER_slist_next (&it))
+ for (i = 0; i < sset->len; i++)
{
- s = GNUNET_CONTAINER_slist_get (&it, NULL);
+ s = sset->states[i];
debug_print_state (s);
}
- GNUNET_CONTAINER_slist_iter_destroy (&it);
}
-void
+static void
debug_print_transitions (struct State *s)
{
- struct GNUNET_CONTAINER_SList_Iterator it;
struct Transition *t;
char *state;
char literal;
- for (it = GNUNET_CONTAINER_slist_begin (s->transitions);
- GNUNET_YES != GNUNET_CONTAINER_slist_end (&it);
- GNUNET_CONTAINER_slist_next (&it))
+ for (t = s->transitions_head; NULL != t; t = t->next)
{
- t = GNUNET_CONTAINER_slist_get(&it, NULL);
-
if (0 == t->literal)
literal = '0';
else
else
state = t->state->name;
- GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Transition %i: On %c to %s\n", t->id, literal, state);
+ GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Transition %i: On %c to %s\n", t->id,
+ literal, state);
}
+}
- GNUNET_CONTAINER_slist_iter_destroy (&it);
+/**
+ * Compare two states. Used for sorting.
+ *
+ * @param a first state
+ * @param b second state
+ *
+ * @return an integer less than, equal to, or greater than zero
+ * if the first argument is considered to be respectively
+ * less than, equal to, or greater than the second.
+ */
+static int
+state_compare (const void *a, const void *b)
+{
+ struct State **s1;
+ struct State **s2;
+
+ s1 = (struct State **) a;
+ s2 = (struct State **) b;
+
+ return (*s1)->id - (*s2)->id;
}
-int
-set_compare (const void *buf1, const size_t len1, const void *buf2, const size_t len2)
+/**
+ * Compare to state sets by comparing the id's of the states that are
+ * contained in each set. Both sets are expected to be sorted by id!
+ *
+ * @param sset1 first state set
+ * @param sset2 second state set
+ *
+ * @return an integer less than, equal to, or greater than zero
+ * if the first argument is considered to be respectively
+ * less than, equal to, or greater than the second.
+ */
+static int
+state_set_compare (struct StateSet *sset1, struct StateSet *sset2)
{
- int c1;
- int c2;
- struct GNUNET_CONTAINER_SList_Iterator it1;
- struct GNUNET_CONTAINER_SList_Iterator it2;
- struct State *s1;
- struct State *s2;
- struct GNUNET_CONTAINER_SList *l1;
- struct GNUNET_CONTAINER_SList *l2;
- const void *el1;
- const void *el2;
- size_t length1;
- size_t length2;
- int rslt;
- int contains;
+ int result;
+ int i;
- if (len1 != len2
- && len1 != sizeof (struct State)
- && len2 != sizeof (struct State))
+ if (NULL == sset1 || NULL == sset2)
return 1;
- s1 = (struct State *)buf1;
- s2 = (struct State *)buf2;
-
- l1 = s1->nfa_set;
- l2 = s2->nfa_set;
+ result = sset1->len - sset2->len;
- c1 = GNUNET_CONTAINER_slist_count (l1);
- c2 = GNUNET_CONTAINER_slist_count (l2);
+ for (i = 0; i < sset1->len; i++)
+ {
+ if (0 != result)
+ break;
- if (c1 != c2)
- return ((c1 > c2) ? 1 : -1);
+ result = state_compare (&sset1->states[i], &sset2->states[i]);
+ }
+ return result;
+}
- rslt = 0;
+/**
+ * Checks if 'elem' is contained in 'set'
+ *
+ * @param set set of states
+ * @param elem state
+ *
+ * @return GNUNET_YES if 'set' contains 'elem, GNUNET_NO otherwise
+ */
+static int
+state_set_contains (struct StateSet *set, struct State *elem)
+{
+ struct State *s;
+ int i;
- for (it1 = GNUNET_CONTAINER_slist_begin (l1);
- GNUNET_YES != GNUNET_CONTAINER_slist_end (&it1);
- GNUNET_CONTAINER_slist_next (&it1))
+ for (i = 0; i < set->len; i++)
{
- el1 = GNUNET_CONTAINER_slist_get (&it1, &length1);
- contains = 0;
+ s = set->states[i];
+ if (0 == memcmp (s, elem, sizeof (struct State)))
+ return GNUNET_YES;
+ }
+ return GNUNET_NO;
+}
- for (it2 = GNUNET_CONTAINER_slist_begin (l2);
- GNUNET_YES != GNUNET_CONTAINER_slist_end (&it2);
- GNUNET_CONTAINER_slist_next (&it2))
- {
- el2 = GNUNET_CONTAINER_slist_get (&it2, &length2);
+/**
+ * Clears the given StateSet 'set'
+ *
+ * @param set set to be cleared
+ */
+static void
+state_set_clear (struct StateSet *set)
+{
+ if (NULL != set)
+ {
+ if (NULL != set->states)
+ GNUNET_free (set->states);
+ GNUNET_free (set);
+ }
+}
- if (length1 != length2)
- {
- GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Comparing lists failed, element size mismatch\n");
- break;
- }
- if (((struct State*)el1)->id == ((struct State*)el2)->id)
- {
- contains = 1;
- break;
- }
- }
- GNUNET_CONTAINER_slist_iter_destroy (&it2);
+/**
+ * Adds a transition from one state to another on 'literal'
+ *
+ * @param ctx context
+ * @param from_state starting state for the transition
+ * @param literal transition label
+ * @param to_state state to where the transition should point to
+ */
+static void
+add_transition (struct GNUNET_REGEX_Context *ctx, struct State *from_state,
+ const char literal, struct State *to_state)
+{
+ struct Transition *t;
- if (0 == contains)
- {
- rslt = 1;
- break;
- }
+ if (NULL == from_state)
+ {
+ GNUNET_log (GNUNET_ERROR_TYPE_ERROR, "Could not create Transition.\n");
+ return;
}
- GNUNET_CONTAINER_slist_iter_destroy (&it1);
- return rslt;
+ t = GNUNET_malloc (sizeof (struct Transition));
+
+ t->id = ctx->transition_id++;
+ t->literal = literal;
+ t->state = to_state;
+
+ GNUNET_CONTAINER_DLL_insert (from_state->transitions_head,
+ from_state->transitions_tail, t);
}
-int
-transition_literal_compare (const void *buf1, const size_t len1, const void *buf2, const size_t len2)
+/**
+ * Clears an automaton fragment. Does not destroy the states inside
+ * the automaton.
+ *
+ * @param a automaton to be cleared
+ */
+static void
+automaton_fragment_clear (struct GNUNET_REGEX_Automaton *a)
{
- struct Transition *t1;
- struct Transition *t2;
+ if (NULL == a)
+ return;
+
+ a->start = NULL;
+ a->end = NULL;
+ a->states_head = NULL;
+ a->states_tail = NULL;
+ a->state_count = 0;
+ GNUNET_free (a);
+}
+
+/**
+ * Frees the memory used by State 's'
+ *
+ * @param s state that should be destroyed
+ */
+static void
+automaton_destroy_state (struct State *s)
+{
+ struct Transition *t;
+ struct Transition *next_t;
+
+ if (NULL == s)
+ return;
- if (len1 != len2
- && len1 != sizeof (struct Transition)
- && len2 != sizeof (struct Transition))
+ if (NULL != s->name)
+ GNUNET_free (s->name);
+
+ for (t = s->transitions_head; NULL != t;)
{
- return 1;
+ next_t = t->next;
+ GNUNET_CONTAINER_DLL_remove (s->transitions_head, s->transitions_tail, t);
+ GNUNET_free (t);
+ t = next_t;
}
- t1 = (struct Transition *)buf1;
- t2 = (struct Transition *)buf2;
+ state_set_clear (s->nfa_set);
- if (t1->literal == t2->literal)
- return 0;
- else if (t1->literal > t2->literal)
- return 1;
- else
- return -1;
+ GNUNET_free (s);
}
-void
-add_transition (struct GNUNET_REGEX_Context *ctx, struct State *from_state, const char literal,
- struct State *to_state)
+/**
+ * Remove a state from the given automaton 'a'. Always use this function
+ * when altering the states of an automaton. Will also remove all transitions
+ * leading to this state, before destroying it.
+ *
+ * @param a automaton
+ * @param s state to remove
+ */
+static void
+automaton_remove_state (struct GNUNET_REGEX_Automaton *a, struct State *s)
{
- struct Transition t;
+ struct State *ss;
+ struct State *s_check;
+ struct Transition *t_check;
- if (NULL == from_state)
- {
- GNUNET_log (GNUNET_ERROR_TYPE_ERROR, "Could not create Transition.\n");
+ if (NULL == a || NULL == s)
return;
+
+ // remove state
+ ss = s;
+ GNUNET_CONTAINER_DLL_remove (a->states_head, a->states_tail, s);
+ a->state_count--;
+
+ // remove all transitions leading to this state
+ for (s_check = a->states_head; NULL != s_check; s_check = s_check->next)
+ {
+ for (t_check = s_check->transitions_head; NULL != t_check;
+ t_check = t_check->next)
+ {
+ if (t_check->state == ss)
+ {
+ GNUNET_CONTAINER_DLL_remove (s_check->transitions_head,
+ s_check->transitions_tail, t_check);
+ s_check->transition_count--;
+ }
+ }
+ }
+
+ automaton_destroy_state (ss);
+}
+
+/**
+ * Merge two states into one. Will merge 's1' and 's2' into 's1' and destroy 's2'.
+ *
+ * @param ctx context
+ * @param a automaton
+ * @param s1 first state
+ * @param s2 second state, will be destroyed
+ */
+static void
+automaton_merge_states (struct GNUNET_REGEX_Context *ctx,
+ struct GNUNET_REGEX_Automaton *a, struct State *s1,
+ struct State *s2)
+{
+ struct State *s_check;
+ struct Transition *t_check;
+ struct Transition *t;
+ char *new_name;
+
+ GNUNET_assert (NULL != ctx && NULL != a && NULL != s1 && NULL != s2);
+
+ // 1. Make all transitions pointing to s2 point to s1
+ for (s_check = a->states_head; NULL != s_check; s_check = s_check->next)
+ {
+ for (t_check = s_check->transitions_head; NULL != t_check;
+ t_check = t_check->next)
+ {
+ if (s_check != s1 && s2 == t_check->state)
+ t_check->state = s1;
+ }
}
- t.id = ctx->transition_id++;
- t.literal = literal;
- t.state = to_state;
+ // 2. Add all transitions from s2 to sX to s1
+ for (t_check = s2->transitions_head; NULL != t_check; t_check = t_check->next)
+ {
+ for (t = s1->transitions_head; NULL != t; t = t->next)
+ {
+ if (t_check->literal != t->literal && NULL != t_check->state &&
+ t_check->state != t->state && t_check->state != s2)
+ {
+ add_transition (ctx, s1, t_check->literal, t_check->state);
+ }
+ }
+ }
- GNUNET_CONTAINER_slist_add (from_state->transitions,
- GNUNET_CONTAINER_SLIST_DISPOSITION_TRANSIENT,
- &t, sizeof t);
+ // 3. Rename s1 to {s1,s2}
+ new_name = GNUNET_malloc (strlen (s1->name) + strlen (s2->name) + 1);
+ strncat (new_name, s1->name, strlen (s1->name));
+ strncat (new_name, s2->name, strlen (s2->name));
+ if (NULL != s1->name)
+ GNUNET_free (s1->name);
+ s1->name = new_name;
+
+ // remove state
+ s_check = s2;
+ GNUNET_CONTAINER_DLL_remove (a->states_head, a->states_tail, s_check);
+ a->state_count--;
+ automaton_destroy_state (s_check);
}
-struct State *
-dfa_create_state (struct GNUNET_REGEX_Context *ctx, struct GNUNET_CONTAINER_SList *states)
+/**
+ * Add a state to the automaton 'a', always use this function to
+ * alter the states DLL of the automaton.
+ *
+ * @param a automaton to add the state to
+ * @param s state that should be added
+ */
+static void
+automaton_add_state (struct GNUNET_REGEX_Automaton *a, struct State *s)
+{
+ GNUNET_CONTAINER_DLL_insert (a->states_head, a->states_tail, s);
+ a->state_count++;
+}
+
+/**
+ * Creates a new DFA state based on a set of NFA states. Needs to be freed
+ * using automaton_destroy_state.
+ *
+ * @param ctx context
+ * @param nfa_states set of NFA states on which the DFA should be based on
+ *
+ * @return new DFA state
+ */
+static struct State *
+dfa_state_create (struct GNUNET_REGEX_Context *ctx, struct StateSet *nfa_states)
{
struct State *s;
char *name;
- struct GNUNET_CONTAINER_SList_Iterator stateit;
- struct GNUNET_CONTAINER_SList_Iterator tranit;
int len = 0;
struct State *cstate;
struct Transition *ctran;
+ int insert = 1;
+ struct Transition *t;
+ int i;
s = GNUNET_malloc (sizeof (struct State));
s->id = ctx->state_id++;
s->accepting = 0;
- s->transitions = GNUNET_CONTAINER_slist_create();
s->marked = 0;
s->name = NULL;
- if (NULL == states)
+ if (NULL == nfa_states)
+ {
+ GNUNET_asprintf (&s->name, "s%i", s->id);
return s;
+ }
- s->nfa_set = states;
+ s->nfa_set = nfa_states;
- if (0 == GNUNET_CONTAINER_slist_count (states))
+ if (nfa_states->len < 1)
return s;
-
// Create a name based on 'sset'
s->name = GNUNET_malloc (sizeof (char) * 2);
strcat (s->name, "{");
name = NULL;
- for (stateit = GNUNET_CONTAINER_slist_begin(states);
- GNUNET_NO == GNUNET_CONTAINER_slist_end (&stateit);
- GNUNET_CONTAINER_slist_next (&stateit))
+ for (i = 0; i < nfa_states->len; i++)
{
- cstate = GNUNET_CONTAINER_slist_get (&stateit, NULL);
- GNUNET_CONTAINER_slist_iter_destroy (&tranit);
+ cstate = nfa_states->states[i];
GNUNET_asprintf (&name, "%i,", cstate->id);
if (NULL != name)
}
// Add a transition for each distinct literal to NULL state
- for (tranit = GNUNET_CONTAINER_slist_begin(cstate->transitions);
- GNUNET_NO == GNUNET_CONTAINER_slist_end (&tranit);
- GNUNET_CONTAINER_slist_next (&tranit))
+ for (ctran = cstate->transitions_head; NULL != ctran; ctran = ctran->next)
{
- ctran = GNUNET_CONTAINER_slist_get(&tranit, NULL);
- if (0 != ctran->literal
- && NULL == GNUNET_CONTAINER_slist_contains2 (s->transitions, ctran, sizeof *ctran, &transition_literal_compare))
+ if (0 != ctran->literal)
{
- add_transition (ctx, s, ctran->literal, NULL);
+ insert = 1;
+
+ for (t = s->transitions_head; NULL != t; t = t->next)
+ {
+ if (t->literal == ctran->literal)
+ {
+ insert = 0;
+ break;
+ }
+ }
+
+ if (insert)
+ add_transition (ctx, s, ctran->literal, NULL);
}
}
+ // If the nfa_states contain an accepting state, the new dfa state is also accepting
if (cstate->accepting)
s->accepting = 1;
}
- GNUNET_CONTAINER_slist_iter_destroy (&stateit);
- s->name[strlen (s->name)-1] = '}';
+ s->name[strlen (s->name) - 1] = '}';
return s;
}
-struct GNUNET_REGEX_Automaton *
-nfa_create (struct State *start, struct State *end)
+/**
+ * Move from the given state 's' to the next state on
+ * transition 'literal'
+ *
+ * @param s starting state
+ * @param literal edge label to follow
+ *
+ * @return new state or NULL, if transition on literal not possible
+ */
+static struct State *
+dfa_move (struct State *s, const char literal)
+{
+ struct Transition *t;
+ struct State *new_s;
+
+ if (NULL == s)
+ return NULL;
+
+ new_s = NULL;
+
+ for (t = s->transitions_head; NULL != t; t = t->next)
+ {
+ if (literal == t->literal)
+ {
+ new_s = t->state;
+ break;
+ }
+ }
+
+ return new_s;
+}
+
+/**
+ * Remove all unreachable states from DFA 'a'. Unreachable states
+ * are those states that are not reachable from the starting state.
+ *
+ * @param a DFA automaton
+ */
+static void
+dfa_remove_unreachable_states (struct GNUNET_REGEX_Automaton *a)
+{
+ struct State *stack[a->state_count];
+ int stack_len;
+ struct State *s;
+ struct Transition *t;
+
+ stack_len = 0;
+
+ // 1. unmark all states
+ for (s = a->states_head; NULL != s; s = s->next)
+ {
+ s->marked = 0;
+ }
+
+ // 2. traverse dfa from start state and mark all visited states
+ stack[stack_len] = a->start;
+ stack_len++;
+ while (stack_len > 0)
+ {
+ s = stack[stack_len - 1];
+ stack_len--;
+ s->marked = 1; // mark s as visited
+ for (t = s->transitions_head; NULL != t; t = t->next)
+ {
+ // add next states to stack
+ if (NULL != t->state && 0 == t->state->marked)
+ stack[++stack_len] = t->state;
+ }
+ }
+
+ // 3. delete all states that were not visited
+ for (s = a->states_head; NULL != s; s = s->next)
+ {
+ if (0 == s->marked)
+ automaton_remove_state (a, s);
+ }
+}
+
+/**
+ * Remove all dead states from the DFA 'a'. Dead states are those
+ * states that do not transition to any other state but themselfes.
+ *
+ * @param a DFA automaton
+ */
+static void
+dfa_remove_dead_states (struct GNUNET_REGEX_Automaton *a)
+{
+ struct State *s;
+ struct Transition *t;
+ int dead;
+
+ GNUNET_assert (DFA == a->type);
+
+ for (s = a->states_head; NULL != s; s = s->next)
+ {
+ if (s->accepting)
+ continue;
+
+ dead = 1;
+ for (t = s->transitions_head; NULL != t; t = t->next)
+ {
+ if (NULL != t->state && t->state != s)
+ {
+ dead = 0;
+ break;
+ }
+ }
+
+ if (0 == dead)
+ continue;
+
+ // state s is dead, remove it
+ automaton_remove_state (a, s);
+ }
+}
+
+/**
+ * Merge all non distinguishable states in the DFA 'a'
+ *
+ * @param ctx context
+ * @param a DFA automaton
+ */
+static void
+dfa_merge_nondistinguishable_states (struct GNUNET_REGEX_Context *ctx,
+ struct GNUNET_REGEX_Automaton *a)
+{
+ int i;
+ int table[a->state_count][a->state_count];
+ struct State *s1;
+ struct State *s2;
+ struct Transition *t1;
+ struct Transition *t2;
+ int change;
+
+ change = 1;
+ for (i = 0, s1 = a->states_head; i < a->state_count && NULL != s1;
+ i++, s1 = s1->next)
+ s1->marked = i;
+
+ // Mark all pairs of accepting/!accepting states
+ for (s1 = a->states_head; NULL != s1; s1 = s1->next)
+ {
+ for (s2 = a->states_head; NULL != s2 && s1 != s2; s2 = s2->next)
+ {
+ if ((s1->accepting && !s2->accepting) ||
+ (!s1->accepting && s2->accepting))
+ {
+ table[s1->marked][s2->marked] = 1;
+ }
+ else
+ table[s1->marked][s2->marked] = 0;
+ }
+ }
+
+ while (0 != change)
+ {
+ change = 0;
+ for (s1 = a->states_head; NULL != s1; s1 = s1->next)
+ {
+ for (s2 = a->states_head; NULL != s2 && s1 != s2; s2 = s2->next)
+ {
+ if (0 != table[s1->marked][s2->marked])
+ continue;
+
+ for (t1 = s1->transitions_head; NULL != t1; t1 = t1->next)
+ {
+ for (t2 = s2->transitions_head; NULL != t2; t2 = t2->next)
+ {
+ if (t1->literal == t2->literal && t1->state == t2->state &&
+ (0 != table[t1->state->marked][t2->state->marked] ||
+ 0 != table[t2->state->marked][t1->state->marked]))
+ {
+ table[s1->marked][s2->marked] = t1->literal;
+ change = 1;
+ }
+ else if (t1->literal != t2->literal && t1->state != t2->state)
+ {
+ table[s1->marked][s2->marked] = -1;
+ change = 1;
+ }
+ }
+ }
+ }
+ }
+ }
+
+ struct State *s2_next;
+
+ for (i = 0, s1 = a->states_head; NULL != s1; s1 = s1->next)
+ {
+ for (s2 = a->states_head; NULL != s2 && s1 != s2; s2 = s2_next)
+ {
+ s2_next = s2->next;
+ if (s1 != s2 && table[s1->marked][s2->marked] == 0)
+ automaton_merge_states (ctx, a, s1, s2);
+ }
+ }
+}
+
+/**
+ * Minimize the given DFA 'a' by removing all unreachable states,
+ * removing all dead states and merging all non distinguishable states
+ *
+ * @param ctx context
+ * @param a DFA automaton
+ */
+static void
+dfa_minimize (struct GNUNET_REGEX_Context *ctx,
+ struct GNUNET_REGEX_Automaton *a)
+{
+ if (NULL == a)
+ return;
+
+ GNUNET_assert (DFA == a->type);
+
+ // 1. remove unreachable states
+ dfa_remove_unreachable_states (a);
+
+ // 2. remove dead states
+ dfa_remove_dead_states (a);
+
+ // 3. Merge nondistinguishable states
+ dfa_merge_nondistinguishable_states (ctx, a);
+}
+
+/**
+ * Creates a new NFA fragment. Needs to be cleared using automaton_fragment_clear.
+ *
+ * @param start starting state
+ * @param end end state
+ *
+ * @return new NFA fragment
+ */
+static struct GNUNET_REGEX_Automaton *
+nfa_fragment_create (struct State *start, struct State *end)
{
struct GNUNET_REGEX_Automaton *n;
n = GNUNET_malloc (sizeof (struct GNUNET_REGEX_Automaton));
+ n->type = NFA;
n->start = NULL;
n->end = NULL;
- n->states = GNUNET_CONTAINER_slist_create ();
if (NULL == start && NULL == end)
return n;
- GNUNET_CONTAINER_slist_add (n->states,
- GNUNET_CONTAINER_SLIST_DISPOSITION_STATIC,
- end,
- sizeof *end);
-
- GNUNET_CONTAINER_slist_add (n->states,
- GNUNET_CONTAINER_SLIST_DISPOSITION_STATIC,
- start,
- sizeof *start);
+ automaton_add_state (n, end);
+ automaton_add_state (n, start);
n->start = start;
n->end = end;
return n;
}
-void
-nfa_add_states (struct GNUNET_REGEX_Automaton *n, struct GNUNET_CONTAINER_SList *states)
+/**
+ * Adds a list of states to the given automaton 'n'.
+ *
+ * @param n automaton to which the states should be added
+ * @param states_head head of the DLL of states
+ * @param states_tail tail of the DLL of states
+ */
+static void
+nfa_add_states (struct GNUNET_REGEX_Automaton *n, struct State *states_head,
+ struct State *states_tail)
{
- // This isn't very pretty. Would be better to use GNUNET_CONTAINER_slist_append, but
- // this function adds to the beginning of dst, which currently breaks "pretty"
- // printing of the graph...
- struct GNUNET_CONTAINER_SList_Iterator i;
struct State *s;
- for (i = GNUNET_CONTAINER_slist_begin (states);
- GNUNET_CONTAINER_slist_end (&i) != GNUNET_YES;
- GNUNET_CONTAINER_slist_next (&i))
+ if (NULL == n || NULL == states_head)
+ {
+ GNUNET_log (GNUNET_ERROR_TYPE_ERROR, "Could not add states\n");
+ return;
+ }
+
+ if (NULL == n->states_head)
+ {
+ n->states_head = states_head;
+ n->states_tail = states_tail;
+ return;
+ }
+ if (NULL != states_head)
{
- s = GNUNET_CONTAINER_slist_get (&i, NULL);
- GNUNET_CONTAINER_slist_add_end (n->states,
- GNUNET_CONTAINER_SLIST_DISPOSITION_STATIC,
- s, sizeof *s);
+ n->states_tail->next = states_head;
+ n->states_tail = states_tail;
}
- GNUNET_CONTAINER_slist_iter_destroy (&i);
+
+ for (s = states_head; NULL != s; s = s->next)
+ n->state_count++;
}
-struct State *
-nfa_create_state (struct GNUNET_REGEX_Context *ctx, int accepting)
+/**
+ * Creates a new NFA state. Needs to be freed using automaton_destroy_state.
+ *
+ * @param ctx context
+ * @param accepting is it an accepting state or not
+ *
+ * @return new NFA state
+ */
+static struct State *
+nfa_state_create (struct GNUNET_REGEX_Context *ctx, int accepting)
{
struct State *s;
s = GNUNET_malloc (sizeof (struct State));
s->id = ctx->state_id++;
s->accepting = accepting;
- s->transitions = GNUNET_CONTAINER_slist_create();
s->marked = 0;
s->name = NULL;
GNUNET_asprintf (&s->name, "s%i", s->id);
return s;
}
-void
-automaton_fragment_clear (struct GNUNET_REGEX_Automaton *a)
+/**
+ * Calculates the NFA closure set for the given state.
+ *
+ * @param s starting point state
+ * @param literal transitioning literal on which to base the closure on,
+ * pass 0 for epsilon transition
+ *
+ * @return sorted nfa closure on 'literal' (epsilon closure if 'literal' is 0)
+ */
+static struct StateSet *
+nfa_closure_create (struct State *s, const char literal)
{
- GNUNET_CONTAINER_slist_destroy (a->states);
- a->start = NULL;
- a->end = NULL;
- GNUNET_free (a);
-}
+ struct StateSet *cls;
+ struct StateSet *cls_check;
+ struct State *clsstate;
+ struct State *currentstate;
+ struct Transition *ctran;
-void
-automaton_destroy_state (struct State *s)
-{
- if (NULL != s->transitions)
- GNUNET_CONTAINER_slist_destroy (s->transitions);
- if (NULL != s->name)
- GNUNET_free (s->name);
- if (NULL != s->nfa_set)
- GNUNET_CONTAINER_slist_destroy(s->nfa_set);
- GNUNET_free (s);
+ if (NULL == s)
+ return NULL;
+
+ cls = GNUNET_malloc (sizeof (struct StateSet));
+ cls_check = GNUNET_malloc (sizeof (struct StateSet));
+
+ // Add start state to closure only for epsilon closure
+ if (0 == literal)
+ GNUNET_array_append (cls->states, cls->len, s);
+
+ GNUNET_array_append (cls_check->states, cls_check->len, s);
+ while (cls_check->len > 0)
+ {
+ currentstate = cls_check->states[cls_check->len - 1];
+ GNUNET_array_grow (cls_check->states, cls_check->len, cls_check->len - 1);
+
+ for (ctran = currentstate->transitions_head; NULL != ctran;
+ ctran = ctran->next)
+ {
+ if (NULL != ctran->state && literal == ctran->literal)
+ {
+ clsstate = ctran->state;
+
+ if (NULL != clsstate &&
+ GNUNET_YES != state_set_contains (cls, clsstate))
+ {
+ GNUNET_array_append (cls->states, cls->len, clsstate);
+ GNUNET_array_append (cls_check->states, cls_check->len, clsstate);
+ }
+ }
+ }
+ }
+ GNUNET_assert (0 == cls_check->len);
+ GNUNET_free (cls_check);
+
+ if (cls->len > 1)
+ qsort (cls->states, cls->len, sizeof (struct State *), state_compare);
+
+ return cls;
}
-void
-mark_all_states (struct GNUNET_REGEX_Automaton *n, int marked)
+/**
+ * Calculates the closure set for the given set of states.
+ *
+ * @param states list of states on which to base the closure on
+ * @param literal transitioning literal for which to base the closure on,
+ * pass 0 for epsilon transition
+ *
+ * @return sorted nfa closure on 'literal' (epsilon closure if 'literal' is 0)
+ */
+static struct StateSet *
+nfa_closure_set_create (struct StateSet *states, const char literal)
{
- struct GNUNET_CONTAINER_SList_Iterator it;
struct State *s;
+ struct StateSet *sset;
+ struct StateSet *cls;
+ int i;
+ int j;
+ int k;
+ int contains;
+
+ if (NULL == states)
+ return NULL;
- for (it = GNUNET_CONTAINER_slist_begin (n->states);
- GNUNET_YES != GNUNET_CONTAINER_slist_end (&it);
- GNUNET_CONTAINER_slist_next (&it))
+ cls = GNUNET_malloc (sizeof (struct StateSet));
+
+ for (i = 0; i < states->len; i++)
{
- s = GNUNET_CONTAINER_slist_get (&it, NULL);
- s->marked = marked;
+ s = states->states[i];
+ sset = nfa_closure_create (s, literal);
+
+ for (j = 0; j < sset->len; j++)
+ {
+ contains = 0;
+ for (k = 0; k < cls->len; k++)
+ {
+ if (sset->states[j]->id == cls->states[k]->id)
+ {
+ contains = 1;
+ break;
+ }
+ }
+ if (!contains)
+ GNUNET_array_append (cls->states, cls->len, sset->states[j]);
+ }
+ state_set_clear (sset);
}
- GNUNET_CONTAINER_slist_iter_destroy (&it);
+ if (cls->len > 1)
+ qsort (cls->states, cls->len, sizeof (struct State *), state_compare);
+
+ return cls;
}
-void
+/**
+ * Pops two NFA fragments (a, b) from the stack and concatenates them (ab)
+ *
+ * @param ctx context
+ */
+static void
nfa_add_concatenation (struct GNUNET_REGEX_Context *ctx)
{
struct GNUNET_REGEX_Automaton *a;
struct GNUNET_REGEX_Automaton *b;
struct GNUNET_REGEX_Automaton *new;
- b = stack_pop (ctx->stack, sizeof (struct GNUNET_REGEX_Automaton));
- a = stack_pop (ctx->stack, sizeof (struct GNUNET_REGEX_Automaton));
+ b = ctx->stack_tail;
+ GNUNET_CONTAINER_DLL_remove (ctx->stack_head, ctx->stack_tail, b);
+ a = ctx->stack_tail;
+ GNUNET_CONTAINER_DLL_remove (ctx->stack_head, ctx->stack_tail, a);
add_transition (ctx, a->end, 0, b->start);
a->end->accepting = 0;
b->end->accepting = 1;
- new = nfa_create (NULL, NULL);
- nfa_add_states (new, a->states);
- nfa_add_states (new, b->states);
+ new = nfa_fragment_create (NULL, NULL);
+ nfa_add_states (new, a->states_head, a->states_tail);
+ nfa_add_states (new, b->states_head, b->states_tail);
new->start = a->start;
new->end = b->end;
automaton_fragment_clear (a);
automaton_fragment_clear (b);
- stack_push (ctx->stack, new, sizeof *new);
+ GNUNET_CONTAINER_DLL_insert_tail (ctx->stack_head, ctx->stack_tail, new);
}
-void
+/**
+ * Pops a NFA fragment from the stack (a) and adds a new fragment (a*)
+ *
+ * @param ctx context
+ */
+static void
nfa_add_star_op (struct GNUNET_REGEX_Context *ctx)
{
struct GNUNET_REGEX_Automaton *a;
struct State *start;
struct State *end;
- a = stack_pop (ctx->stack, sizeof (struct GNUNET_REGEX_Automaton));
+ a = ctx->stack_tail;
+ GNUNET_CONTAINER_DLL_remove (ctx->stack_head, ctx->stack_tail, a);
if (NULL == a)
{
return;
}
- start = nfa_create_state (ctx, 0);
- end = nfa_create_state (ctx, 1);
+ start = nfa_state_create (ctx, 0);
+ end = nfa_state_create (ctx, 1);
add_transition (ctx, start, 0, a->start);
add_transition (ctx, start, 0, end);
a->end->accepting = 0;
end->accepting = 1;
- new = nfa_create (start, end);
- nfa_add_states (new, a->states);
+ new = nfa_fragment_create (start, end);
+ nfa_add_states (new, a->states_head, a->states_tail);
automaton_fragment_clear (a);
- stack_push (ctx->stack, new, sizeof *new);
+ GNUNET_CONTAINER_DLL_insert_tail (ctx->stack_head, ctx->stack_tail, new);
}
-void
+/**
+ * Pops an NFA fragment (a) from the stack and adds a new fragment (a+)
+ *
+ * @param ctx context
+ */
+static void
nfa_add_plus_op (struct GNUNET_REGEX_Context *ctx)
{
struct GNUNET_REGEX_Automaton *a;
- a = stack_pop (ctx->stack, sizeof (struct GNUNET_REGEX_Automaton));
+ a = ctx->stack_tail;
+ GNUNET_CONTAINER_DLL_remove (ctx->stack_head, ctx->stack_tail, a);
add_transition (ctx, a->end, 0, a->start);
- stack_push (ctx->stack, a, sizeof *a);
+ GNUNET_CONTAINER_DLL_insert_tail (ctx->stack_head, ctx->stack_tail, a);
}
-void
+/**
+ * Pops an NFA fragment (a) from the stack and adds a new fragment (a?)
+ *
+ * @param ctx context
+ */
+static void
+nfa_add_question_op (struct GNUNET_REGEX_Context *ctx)
+{
+ struct GNUNET_REGEX_Automaton *a;
+ struct GNUNET_REGEX_Automaton *new;
+ struct State *start;
+ struct State *end;
+
+ a = ctx->stack_tail;
+ GNUNET_CONTAINER_DLL_remove (ctx->stack_head, ctx->stack_tail, a);
+
+ if (NULL == a)
+ {
+ GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
+ "nfa_add_question_op failed, because there was no element on the stack");
+ return;
+ }
+
+ start = nfa_state_create (ctx, 0);
+ end = nfa_state_create (ctx, 1);
+
+ add_transition (ctx, start, 0, a->start);
+ add_transition (ctx, start, 0, end);
+ add_transition (ctx, a->end, 0, end);
+
+ a->end->accepting = 0;
+
+ new = nfa_fragment_create (start, end);
+ nfa_add_states (new, a->states_head, a->states_tail);
+ automaton_fragment_clear (a);
+
+ GNUNET_CONTAINER_DLL_insert_tail (ctx->stack_head, ctx->stack_tail, new);
+}
+
+/**
+ * Pops two NFA fragments (a, b) from the stack and adds a new NFA fragment
+ * that alternates between a and b (a|b)
+ *
+ * @param ctx context
+ */
+static void
nfa_add_alternation (struct GNUNET_REGEX_Context *ctx)
{
struct GNUNET_REGEX_Automaton *a;
struct State *start;
struct State *end;
- b = stack_pop (ctx->stack, sizeof (struct GNUNET_REGEX_Automaton));
- a = stack_pop (ctx->stack, sizeof (struct GNUNET_REGEX_Automaton));
+ b = ctx->stack_tail;
+ GNUNET_CONTAINER_DLL_remove (ctx->stack_head, ctx->stack_tail, b);
+ a = ctx->stack_tail;
+ GNUNET_CONTAINER_DLL_remove (ctx->stack_head, ctx->stack_tail, a);
- start = nfa_create_state (ctx, 0);
- end = nfa_create_state (ctx, 1);
+ start = nfa_state_create (ctx, 0);
+ end = nfa_state_create (ctx, 1);
add_transition (ctx, start, 0, a->start);
add_transition (ctx, start, 0, b->start);
b->end->accepting = 0;
end->accepting = 1;
- new = nfa_create (start, end);
- nfa_add_states (new, a->states);
- nfa_add_states (new, b->states);
+ new = nfa_fragment_create (start, end);
+ nfa_add_states (new, a->states_head, a->states_tail);
+ nfa_add_states (new, b->states_head, b->states_tail);
automaton_fragment_clear (a);
automaton_fragment_clear (b);
- stack_push (ctx->stack, new, sizeof *new);
+ GNUNET_CONTAINER_DLL_insert_tail (ctx->stack_head, ctx->stack_tail, new);
}
-void
+/**
+ * Adds a new nfa fragment to the stack
+ *
+ * @param ctx context
+ * @param lit literal for nfa transition
+ */
+static void
nfa_add_literal (struct GNUNET_REGEX_Context *ctx, const char lit)
{
struct GNUNET_REGEX_Automaton *n;
struct State *start;
struct State *end;
- start = nfa_create_state (ctx, 0);
- end = nfa_create_state (ctx, 1);
+ GNUNET_assert (NULL != ctx);
+
+ start = nfa_state_create (ctx, 0);
+ end = nfa_state_create (ctx, 1);
add_transition (ctx, start, lit, end);
- n = nfa_create (start, end);
- stack_push (ctx->stack, n, sizeof *n);
+ n = nfa_fragment_create (start, end);
+ GNUNET_assert (NULL != n);
+ GNUNET_CONTAINER_DLL_insert_tail (ctx->stack_head, ctx->stack_tail, n);
}
/**
- * Calculates the closure set for the given set of states.
+ * Construct an NFA by parsing the regex string of length 'len'.
*
- * @param states set of states for which to calculate the closure
- * @param count number of states in 'states'
- * @param literal for the transition
+ * @param regex regular expression string
+ * @param len length of the string
*
- * @return set of states that can be reached from the given 'states' when
- * using only 'literal' transitions
+ * @return NFA, needs to be freed using GNUNET_REGEX_destroy_automaton
*/
-struct GNUNET_CONTAINER_SList *
-create_nfa_closure (struct GNUNET_CONTAINER_SList *states, const char literal)
-{
- struct GNUNET_CONTAINER_SList_Iterator stateit;
- struct GNUNET_CONTAINER_SList_Iterator tranit;
- struct GNUNET_CONTAINER_SList *cls;
- struct GNUNET_CONTAINER_SList *cls_check;
- struct State *s;
- struct State *currentstate;
- struct Transition *currenttransition;
- struct State *clsstate;
-
- cls = GNUNET_CONTAINER_slist_create ();
-
- for (stateit = GNUNET_CONTAINER_slist_begin (states);
- GNUNET_YES != GNUNET_CONTAINER_slist_end (&stateit);
- GNUNET_CONTAINER_slist_next (&stateit))
- {
- s = GNUNET_CONTAINER_slist_get (&stateit, NULL);
- cls_check = GNUNET_CONTAINER_slist_create ();
-
- // Add start state to closure only for epsilon closure
- if (0 == literal)
- {
- GNUNET_CONTAINER_slist_add (cls,
- GNUNET_CONTAINER_SLIST_DISPOSITION_STATIC,
- s, sizeof *s);
- }
-
- stack_push (cls_check, s, sizeof *s);
-
- while (!stack_empty(cls_check))
- {
- currentstate = stack_pop(cls_check, sizeof (struct State));
-
- for (tranit = GNUNET_CONTAINER_slist_begin (currentstate->transitions);
- GNUNET_CONTAINER_slist_end (&tranit) != GNUNET_YES;
- GNUNET_CONTAINER_slist_next (&tranit))
- {
- currenttransition = GNUNET_CONTAINER_slist_get (&tranit, NULL);
-
- if (NULL != currenttransition->state
- && literal == currenttransition->literal)
- {
- clsstate = currenttransition->state;
-
- if (NULL == clsstate)
- break;
-
- if (GNUNET_YES != GNUNET_CONTAINER_slist_contains (cls, clsstate, sizeof *clsstate))
- {
- GNUNET_CONTAINER_slist_add (cls,
- GNUNET_CONTAINER_SLIST_DISPOSITION_STATIC,
- clsstate, sizeof *clsstate);
- stack_push (cls_check, clsstate, sizeof *clsstate);
- }
- }
- }
- GNUNET_CONTAINER_slist_iter_destroy (&tranit);
- }
-
- GNUNET_assert (stack_empty (cls_check));
- GNUNET_CONTAINER_slist_destroy (cls_check);
- }
- GNUNET_CONTAINER_slist_iter_destroy (&stateit);
-
- return cls;
-}
-
-struct GNUNET_CONTAINER_SList *
-GNUNET_REGEX_move (struct GNUNET_REGEX_Automaton *a, struct State *s, const char literal)
-{
- struct GNUNET_CONTAINER_SList *l;
- struct GNUNET_CONTAINER_SList_Iterator it;
- struct Transition *ctran;
-
- if (!GNUNET_CONTAINER_slist_contains (a->states, s, sizeof *s))
- {
- GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
- "State %s is not part of the given automaton", s->name);
- return NULL;
- }
-
- l = GNUNET_CONTAINER_slist_create ();
-
- for (it = GNUNET_CONTAINER_slist_begin (s->transitions);
- GNUNET_YES != GNUNET_CONTAINER_slist_end (&it);
- GNUNET_CONTAINER_slist_next (&it))
- {
- ctran = GNUNET_CONTAINER_slist_get (&it, NULL);
- if (literal == ctran->literal)
- GNUNET_CONTAINER_slist_add (l, GNUNET_CONTAINER_SLIST_DISPOSITION_STATIC,
- ctran->state, sizeof *(ctran->state));
- }
- GNUNET_CONTAINER_slist_iter_destroy (&it);
-
- return l;
-}
-
struct GNUNET_REGEX_Automaton *
GNUNET_REGEX_construct_nfa (const char *regex, const size_t len)
{
struct GNUNET_REGEX_Context ctx;
struct GNUNET_REGEX_Automaton *nfa;
+ const char *regexp;
char *error_msg;
unsigned int count;
unsigned int altcount;
{
int altcount;
int atomcount;
- }*p;
+ } *p;
GNUNET_REGEX_context_init (&ctx);
+ regexp = regex;
p = NULL;
error_msg = NULL;
altcount = 0;
atomcount = 0;
pcount = 0;
- for (count = 0; count < len && *regex; count++, regex++)
+ for (count = 0; count < len && *regexp; count++, regexp++)
{
- switch (*regex)
+ switch (*regexp)
{
case '(':
if (atomcount > 1)
}
nfa_add_plus_op (&ctx);
break;
+ case '?':
+ if (atomcount == 0)
+ {
+ error_msg = "Cannot append '?' to nothing";
+ goto error;
+ }
+ nfa_add_question_op (&ctx);
+ break;
case 92: /* escape: \ */
- regex++;
+ regexp++;
count++;
default:
if (atomcount > 1)
--atomcount;
nfa_add_concatenation (&ctx);
}
- nfa_add_literal (&ctx, *regex);
+ nfa_add_literal (&ctx, *regexp);
atomcount++;
break;
}
if (NULL != p)
GNUNET_free (p);
- nfa = stack_pop (ctx.stack, sizeof (struct GNUNET_REGEX_Automaton));
+ nfa = ctx.stack_tail;
+ GNUNET_CONTAINER_DLL_remove (ctx.stack_head, ctx.stack_tail, nfa);
- if (!stack_empty (ctx.stack))
+
+ if (NULL != ctx.stack_head)
{
error_msg = "Creating the NFA failed. NFA stack was not empty!";
goto error;
}
- GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
- "Created NFA with %i States and a total of %i Transitions\n",
- GNUNET_CONTAINER_slist_count (nfa->states),
- ctx.transition_id);
-
- GNUNET_REGEX_context_destroy (&ctx);
-
return nfa;
error:
GNUNET_log (GNUNET_ERROR_TYPE_ERROR, "Could not parse regex\n");
if (NULL != error_msg)
GNUNET_log (GNUNET_ERROR_TYPE_ERROR, "%s\n", error_msg);
- GNUNET_free (p);
- while (!stack_empty (ctx.stack))
- GNUNET_REGEX_destroy_automaton (stack_pop (ctx.stack, sizeof (struct GNUNET_REGEX_Automaton)));
- GNUNET_REGEX_context_destroy (&ctx);
+ if (NULL != p)
+ GNUNET_free (p);
+ while (NULL != ctx.stack_tail)
+ {
+ GNUNET_REGEX_automaton_destroy (ctx.stack_tail);
+ GNUNET_CONTAINER_DLL_remove (ctx.stack_head, ctx.stack_tail,
+ ctx.stack_tail);
+ }
return NULL;
}
+/**
+ * Free the memory allocated by constructing the GNUNET_REGEX_Automaton
+ * data structure.
+ *
+ * @param a automaton to be destroyed
+ */
void
-GNUNET_REGEX_destroy_automaton (struct GNUNET_REGEX_Automaton *a)
+GNUNET_REGEX_automaton_destroy (struct GNUNET_REGEX_Automaton *a)
{
- struct GNUNET_CONTAINER_SList_Iterator it;
+ struct State *s;
+ struct State *next_state;
if (NULL == a)
return;
- for (it = GNUNET_CONTAINER_slist_begin (a->states);
- GNUNET_YES != GNUNET_CONTAINER_slist_end (&it);
- GNUNET_CONTAINER_slist_next (&it))
+ for (s = a->states_head; NULL != s;)
{
- automaton_destroy_state (GNUNET_CONTAINER_slist_get (&it, NULL));
+ next_state = s->next;
+ automaton_destroy_state (s);
+ s = next_state;
}
- GNUNET_CONTAINER_slist_iter_destroy (&it);
- GNUNET_CONTAINER_slist_destroy (a->states);
+
GNUNET_free (a);
}
-
+/**
+ * Construct DFA for the given 'regex' of length 'len'
+ *
+ * @param regex regular expression string
+ * @param len length of the regular expression
+ *
+ * @return DFA, needs to be freed using GNUNET_REGEX_destroy_automaton
+ */
struct GNUNET_REGEX_Automaton *
GNUNET_REGEX_construct_dfa (const char *regex, const size_t len)
{
struct GNUNET_REGEX_Context ctx;
struct GNUNET_REGEX_Automaton *dfa;
struct GNUNET_REGEX_Automaton *nfa;
- struct GNUNET_CONTAINER_SList *tmp;
- struct GNUNET_CONTAINER_SList *nfa_set;
- struct GNUNET_CONTAINER_SList *sset;
- struct GNUNET_CONTAINER_SList *dfa_stack;
- struct GNUNET_CONTAINER_SList_Iterator tranit;
- struct Transition *currenttransition;
+ struct StateSet *tmp;
+ struct StateSet *nfa_set;
+ struct StateSet *dfa_stack;
+ struct Transition *ctran;
struct State *dfa_state;
struct State *new_dfa_state;
struct State *state_contains;
+ struct State *state_iter;
GNUNET_REGEX_context_init (&ctx);
// Create NFA
nfa = GNUNET_REGEX_construct_nfa (regex, len);
- dfa_stack = GNUNET_CONTAINER_slist_create ();
+ if (NULL == nfa)
+ {
+ GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
+ "Could not create DFA, because NFA creation failed\n");
+ return NULL;
+ }
- // Initialize new dfa
dfa = GNUNET_malloc (sizeof (struct GNUNET_REGEX_Automaton));
- dfa->states = GNUNET_CONTAINER_slist_create ();
+ dfa->type = DFA;
// Create DFA start state from epsilon closure
- sset = GNUNET_CONTAINER_slist_create ();
- GNUNET_CONTAINER_slist_add (sset, GNUNET_CONTAINER_SLIST_DISPOSITION_STATIC,
- nfa->start, sizeof *(nfa->start));
- nfa_set = create_nfa_closure (sset, 0);
- GNUNET_CONTAINER_slist_destroy (sset);
- dfa->start = dfa_create_state (&ctx, nfa_set);
- GNUNET_CONTAINER_slist_add (dfa->states, GNUNET_CONTAINER_SLIST_DISPOSITION_STATIC,
- dfa->start, sizeof *(dfa->start));
- stack_push (dfa_stack, dfa->start, sizeof *(dfa->start));
-
- while (!stack_empty(dfa_stack))
+ dfa_stack = GNUNET_malloc (sizeof (struct StateSet));
+ nfa_set = nfa_closure_create (nfa->start, 0);
+ dfa->start = dfa_state_create (&ctx, nfa_set);
+ automaton_add_state (dfa, dfa->start);
+ GNUNET_array_append (dfa_stack->states, dfa_stack->len, dfa->start);
+
+ // Create dfa states by combining nfa states
+ while (dfa_stack->len > 0)
{
- dfa_state = stack_pop (dfa_stack, sizeof (struct State));
+ dfa_state = dfa_stack->states[dfa_stack->len - 1];
+ GNUNET_array_grow (dfa_stack->states, dfa_stack->len, dfa_stack->len - 1);
- for (tranit = GNUNET_CONTAINER_slist_begin(dfa_state->transitions);
- GNUNET_YES != GNUNET_CONTAINER_slist_end (&tranit);
- GNUNET_CONTAINER_slist_next (&tranit))
+ for (ctran = dfa_state->transitions_head; NULL != ctran;
+ ctran = ctran->next)
{
- currenttransition = GNUNET_CONTAINER_slist_get (&tranit, NULL);
-
- if (0 != currenttransition->literal
- && NULL == currenttransition->state)
+ if (0 != ctran->literal && NULL == ctran->state)
{
- tmp = create_nfa_closure (dfa_state->nfa_set, currenttransition->literal);
- nfa_set = create_nfa_closure (tmp, 0);
- new_dfa_state = dfa_create_state (&ctx, nfa_set);
- GNUNET_CONTAINER_slist_destroy (tmp);
-
- state_contains = GNUNET_CONTAINER_slist_contains2 (dfa->states,
- new_dfa_state,
- sizeof *new_dfa_state,
- &set_compare);
+ tmp = nfa_closure_set_create (dfa_state->nfa_set, ctran->literal);
+ nfa_set = nfa_closure_set_create (tmp, 0);
+ state_set_clear (tmp);
+ new_dfa_state = dfa_state_create (&ctx, nfa_set);
+ state_contains = NULL;
+ for (state_iter = dfa->states_head; NULL != state_iter;
+ state_iter = state_iter->next)
+ {
+ if (0 ==
+ state_set_compare (state_iter->nfa_set, new_dfa_state->nfa_set))
+ state_contains = state_iter;
+ }
+
if (NULL == state_contains)
{
- GNUNET_CONTAINER_slist_add_end (dfa->states, GNUNET_CONTAINER_SLIST_DISPOSITION_STATIC,
- new_dfa_state, sizeof *new_dfa_state);
- stack_push (dfa_stack, new_dfa_state, sizeof *new_dfa_state);
- currenttransition->state = new_dfa_state;
+ automaton_add_state (dfa, new_dfa_state);
+ GNUNET_array_append (dfa_stack->states, dfa_stack->len,
+ new_dfa_state);
+ ctran->state = new_dfa_state;
}
else
- currenttransition->state = state_contains;
+ {
+ ctran->state = state_contains;
+ automaton_destroy_state (new_dfa_state);
+ }
}
}
-
- GNUNET_CONTAINER_slist_iter_destroy (&tranit);
}
- GNUNET_CONTAINER_slist_destroy (dfa_stack);
- GNUNET_REGEX_destroy_automaton (nfa);
- GNUNET_REGEX_context_destroy (&ctx);
- GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
- "Created DFA with %i States\n",
- GNUNET_CONTAINER_slist_count (dfa->states));
+ GNUNET_free (dfa_stack);
+ GNUNET_REGEX_automaton_destroy (nfa);
+
+ dfa_minimize (&ctx, dfa);
return dfa;
}
+/**
+ * Save the given automaton as a GraphViz dot file
+ *
+ * @param a the automaton to be saved
+ * @param filename where to save the file
+ */
void
-GNUNET_REGEX_save_nfa_graph (struct GNUNET_REGEX_Automaton *n, const char *filename)
+GNUNET_REGEX_automaton_save_graph (struct GNUNET_REGEX_Automaton *a,
+ const char *filename)
{
- struct GNUNET_CONTAINER_SList_Iterator stateit;
- struct GNUNET_CONTAINER_SList_Iterator tranit;
struct State *s;
struct Transition *ctran;
char *s_acc = NULL;
char *end;
FILE *p;
- if (NULL == n)
+ if (NULL == a)
{
GNUNET_log (GNUNET_ERROR_TYPE_ERROR, "Could not print NFA, was NULL!");
return;
start = "digraph G {\nrankdir=LR\n";
fwrite (start, strlen (start), 1, p);
- for (stateit = GNUNET_CONTAINER_slist_begin (n->states);
- GNUNET_YES != GNUNET_CONTAINER_slist_end (&stateit);
- GNUNET_CONTAINER_slist_next (&stateit))
+ for (s = a->states_head; NULL != s; s = s->next)
{
-
- s = GNUNET_CONTAINER_slist_get (&stateit, NULL);
-
if (s->accepting)
{
GNUNET_asprintf (&s_acc, "\"%s\" [shape=doublecircle];\n", s->name);
s->marked = 1;
- for (tranit = GNUNET_CONTAINER_slist_begin(s->transitions);
- GNUNET_YES != GNUNET_CONTAINER_slist_end (&tranit);
- GNUNET_CONTAINER_slist_next (&tranit))
+ for (ctran = s->transitions_head; NULL != ctran; ctran = ctran->next)
{
- ctran = GNUNET_CONTAINER_slist_get (&tranit, NULL);
-
if (NULL == ctran->state)
{
GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
if (ctran->literal == 0)
{
- GNUNET_asprintf (&s_tran, "\"%s\" -> \"%s\" [label = \"epsilon\"];\n", s->name,
- ctran->state->name);
+ GNUNET_asprintf (&s_tran, "\"%s\" -> \"%s\" [label = \"epsilon\"];\n",
+ s->name, ctran->state->name);
}
else
{
- GNUNET_asprintf (&s_tran, "\"%s\" -> \"%s\" [label = \"%c\"];\n", s->name,
- ctran->state->name, ctran->literal);
+ GNUNET_asprintf (&s_tran, "\"%s\" -> \"%s\" [label = \"%c\"];\n",
+ s->name, ctran->state->name, ctran->literal);
}
fwrite (s_tran, strlen (s_tran), 1, p);
GNUNET_free (s_tran);
}
- GNUNET_CONTAINER_slist_iter_destroy (&tranit);
}
- GNUNET_CONTAINER_slist_iter_destroy (&stateit);
end = "\n}\n";
fwrite (end, strlen (end), 1, p);
fclose (p);
}
+
+/**
+ * Evaluates the given string using the given DFA automaton
+ *
+ * @param a automaton, type must be DFA
+ * @param string string that should be evaluated
+ *
+ * @return 0 if string matches, non 0 otherwise
+ */
+static int
+evaluate_dfa (struct GNUNET_REGEX_Automaton *a, const char *string)
+{
+ const char *strp;
+ struct State *s;
+
+ if (DFA != a->type)
+ {
+ GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
+ "Tried to evaluate DFA, but NFA automaton given");
+ return -1;
+ }
+
+ s = a->start;
+
+ for (strp = string; NULL != strp && *strp; strp++)
+ {
+ s = dfa_move (s, *strp);
+ if (NULL == s)
+ break;
+ }
+
+ if (NULL != s && s->accepting)
+ return 0;
+
+ return 1;
+}
+
+/**
+ * Evaluates the given string using the given NFA automaton
+ *
+ * @param a automaton, type must be NFA
+ * @param string string that should be evaluated
+ *
+ * @return 0 if string matches, non 0 otherwise
+ */
+static int
+evaluate_nfa (struct GNUNET_REGEX_Automaton *a, const char *string)
+{
+ const char *strp;
+ struct State *s;
+ struct StateSet *sset;
+ struct StateSet *new_sset;
+ int i;
+ int result;
+
+ if (NFA != a->type)
+ {
+ GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
+ "Tried to evaluate NFA, but DFA automaton given");
+ return -1;
+ }
+
+ result = 1;
+ strp = string;
+ sset = nfa_closure_create (a->start, 0);
+
+ for (strp = string; NULL != strp && *strp; strp++)
+ {
+ new_sset = nfa_closure_set_create (sset, *strp);
+ state_set_clear (sset);
+ sset = nfa_closure_set_create (new_sset, 0);
+ state_set_clear (new_sset);
+ }
+
+ for (i = 0; i < sset->len; i++)
+ {
+ s = sset->states[i];
+ if (NULL != s && s->accepting)
+ {
+ result = 0;
+ break;
+ }
+ }
+
+ state_set_clear (sset);
+ return result;
+}
+
+/**
+ * Evaluates the given 'string' against the given compiled regex
+ *
+ * @param a automaton
+ * @param string string to check
+ *
+ * @return 0 if string matches, non 0 otherwise
+ */
+int
+GNUNET_REGEX_eval (struct GNUNET_REGEX_Automaton *a, const char *string)
+{
+ int result;
+
+ switch (a->type)
+ {
+ case DFA:
+ result = evaluate_dfa (a, string);
+ break;
+ case NFA:
+ result = evaluate_nfa (a, string);
+ break;
+ default:
+ GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
+ "Evaluating regex failed, automaton has no type!\n");
+ result = GNUNET_SYSERR;
+ break;
+ }
+
+ return result;
+}
projects / oweals / gnunet.git / blobdiff