*/
/**
* @file src/regex/regex.c
- * @brief library to create automatons from regular expressions
+ * @brief library to create Deterministic Finite Automatons (DFAs) from regular
+ * expressions (regexes). Used by mesh for announcing regexes in the network and
+ * matching strings against published regexes.
* @author Maximilian Szengel
*/
#include "platform.h"
#include "gnunet_container_lib.h"
#include "gnunet_crypto_lib.h"
#include "gnunet_regex_lib.h"
-#include "regex.h"
-
-#define initial_bits 10
-
-/**
- * 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
-{
- /**
- * Unique state id.
- */
- unsigned int state_id;
-
- /**
- * Unique transition id.
- */
- unsigned int transition_id;
-
- /**
- * Unique SCC (Strongly Connected Component) id.
- */
- unsigned int scc_id;
-
- /**
- * DLL of GNUNET_REGEX_Automaton's used as a stack.
- */
- struct GNUNET_REGEX_Automaton *stack_head;
-
- /**
- * DLL of GNUNET_REGEX_Automaton's used as a stack.
- */
- struct GNUNET_REGEX_Automaton *stack_tail;
-};
-
-/**
- * Type of an automaton.
- */
-enum GNUNET_REGEX_automaton_type
-{
- NFA,
- DFA
-};
-
-/**
- * Automaton representation.
- */
-struct GNUNET_REGEX_Automaton
-{
- /**
- * 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 GNUNET_REGEX_State *start;
-
- /**
- * End state of the automaton.
- */
- struct GNUNET_REGEX_State *end;
-
- /**
- * Number of states in the automaton.
- */
- unsigned int state_count;
-
- /**
- * DLL of states.
- */
- struct GNUNET_REGEX_State *states_head;
-
- /**
- * DLL of states
- */
- struct GNUNET_REGEX_State *states_tail;
-
- /**
- * Type of the automaton.
- */
- enum GNUNET_REGEX_automaton_type type;
-};
+#include "regex_internal.h"
/**
- * A state. Can be used in DFA and NFA automatons.
+ * Set this to GNUNET_YES to enable state naming. Used to debug NFA->DFA
+ * creation. Disabled by default for better performance.
*/
-struct GNUNET_REGEX_State
-{
- /**
- * This is a linked list.
- */
- struct GNUNET_REGEX_State *prev;
-
- /**
- * This is a linked list.
- */
- struct GNUNET_REGEX_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;
-
- /**
- * Marking the state as contained. This is used for checking, if the state is
- * contained in a set in constant time
- */
- int contained;
-
- /**
- * Marking the state as part of an SCC (Strongly Connected Component). All
- * states with the same scc_id are part of the same SCC. scc_id is 0, if state
- * is not a part of any SCC.
- */
- unsigned int scc_id;
-
- /**
- * Used for SCC detection.
- */
- int index;
-
- /**
- * Used for SCC detection.
- */
- int lowlink;
-
- /**
- * Human readable name of the automaton. Used for debugging and graph
- * creation.
- */
- char *name;
-
- /**
- * Hash of the state.
- */
- GNUNET_HashCode hash;
-
- /**
- * Proof for this state.
- */
- char *proof;
-
- /**
- * 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 GNUNET_REGEX_StateSet *nfa_set;
-};
+#define REGEX_DEBUG_DFA GNUNET_NO
/**
- * Transition between two states. Each state can have 0-n transitions. If label
- * is 0, this is considered to be an epsilon transition.
+ * Set of states using MDLL API.
*/
-struct Transition
+struct GNUNET_REGEX_StateSet_MDLL
{
/**
- * This is a linked list.
- */
- struct Transition *prev;
-
- /**
- * This is a linked list.
- */
- struct Transition *next;
-
- /**
- * Unique id of this transition.
- */
- unsigned int id;
-
- /**
- * Label for this transition. This is basically the edge label for the graph.
- */
- char label;
-
- /**
- * State to which this transition leads.
+ * MDLL of states.
*/
- struct GNUNET_REGEX_State *to_state;
-
- /**
- * State from which this transition origins.
- */
- struct GNUNET_REGEX_State *from_state;
-};
+ struct GNUNET_REGEX_State *head;
-/**
- * Set of states.
- */
-struct GNUNET_REGEX_StateSet
-{
/**
- * Array of states.
+ * MDLL of states.
*/
- struct GNUNET_REGEX_State **states;
+ struct GNUNET_REGEX_State *tail;
/**
- * Length of the 'states' array.
+ * Length of the MDLL.
*/
unsigned int len;
};
-static void
-debug_print_state (struct GNUNET_REGEX_State *s)
-{
- GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
- "State %i: %s marked: %i accepting: %i scc_id: %i transitions: %i\n",
- s->id, s->name, s->marked, s->accepting, s->scc_id,
- s->transition_count);
-}
-
-static void
-debug_print_states (struct GNUNET_REGEX_StateSet *sset)
-{
- struct GNUNET_REGEX_State *s;
- int i;
-
- for (i = 0; i < sset->len; i++)
- {
- s = sset->states[i];
- debug_print_state (s);
- }
-}
-
-static void
-debug_print_transitions (struct GNUNET_REGEX_State *s)
-{
- struct Transition *t;
- char *state;
- char label;
-
- for (t = s->transitions_head; NULL != t; t = t->next)
- {
- if (0 == t->label)
- label = '0';
- else
- label = t->label;
-
- if (NULL == t->to_state)
- state = "NULL";
- else
- state = t->to_state->name;
-
- GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Transition %i: On %c to %s\n", t->id,
- label, state);
- }
-}
/**
- * Recursive function doing DFS with 'v' as a start, detecting all SCCs inside
- * the subgraph reachable from 'v'. Used with scc_tarjan function to detect all
- * SCCs inside an automaton.
+ * Append state to the given StateSet '
*
- * @param ctx context
- * @param v start vertex
- * @param index current index
- * @param stack stack for saving all SCCs
- * @param stack_size current size of the stack
+ * @param set set to be modified
+ * @param state state to be appended
*/
static void
-scc_tarjan_strongconnect (struct GNUNET_REGEX_Context *ctx,
- struct GNUNET_REGEX_State *v, int *index,
- struct GNUNET_REGEX_State **stack,
- unsigned int *stack_size)
+state_set_append (struct GNUNET_REGEX_StateSet *set,
+ struct GNUNET_REGEX_State *state)
{
- struct GNUNET_REGEX_State *w;
- struct Transition *t;
-
- v->index = *index;
- v->lowlink = *index;
- (*index)++;
- stack[(*stack_size)++] = v;
- v->contained = 1;
-
- for (t = v->transitions_head; NULL != t; t = t->next)
- {
- w = t->to_state;
- if (NULL != w && w->index < 0)
- {
- scc_tarjan_strongconnect (ctx, w, index, stack, stack_size);
- v->lowlink = (v->lowlink > w->lowlink) ? w->lowlink : v->lowlink;
- }
- else if (0 != w->contained)
- v->lowlink = (v->lowlink > w->index) ? w->index : v->lowlink;
- }
-
- if (v->lowlink == v->index)
- {
- w = stack[--(*stack_size)];
- w->contained = 0;
-
- if (v != w)
- {
- ctx->scc_id++;
- while (v != w)
- {
- w->scc_id = ctx->scc_id;
- w = stack[--(*stack_size)];
- w->contained = 0;
- }
- w->scc_id = ctx->scc_id;
- }
- }
+ if (set->off == set->size)
+ GNUNET_array_grow (set->states, set->size, set->size * 2 + 4);
+ set->states[set->off++] = state;
}
+
/**
- * Detect all SCCs (Strongly Connected Components) inside the given automaton.
- * SCCs will be marked using the scc_id on each state.
+ * Compare two strings for equality. If either is NULL they are not equal.
*
- * @param ctx context
- * @param a automaton
+ * @param str1 first string for comparison.
+ * @param str2 second string for comparison.
+ *
+ * @return 0 if the strings are the same or both NULL, 1 or -1 if not.
*/
-static void
-scc_tarjan (struct GNUNET_REGEX_Context *ctx, struct GNUNET_REGEX_Automaton *a)
+static int
+nullstrcmp (const char *str1, const char *str2)
{
- unsigned int i;
- int index;
- struct GNUNET_REGEX_State *v;
- struct GNUNET_REGEX_State *stack[a->state_count];
- unsigned int stack_size;
-
- for (v = a->states_head; NULL != v; v = v->next)
- {
- v->contained = 0;
- v->index = -1;
- v->lowlink = -1;
- }
-
- stack_size = 0;
- index = 0;
+ if ((NULL == str1) != (NULL == str2))
+ return -1;
+ if ((NULL == str1) && (NULL == str2))
+ return 0;
- for (i = 0, v = a->states_head; NULL != v; v = v->next)
- {
- if (v->index < 0)
- scc_tarjan_strongconnect (ctx, v, &index, stack, &stack_size);
- }
+ return strcmp (str1, str2);
}
+
/**
* Adds a transition from one state to another on 'label'. Does not add
* duplicate states.
*/
static void
state_add_transition (struct GNUNET_REGEX_Context *ctx,
- struct GNUNET_REGEX_State *from_state, const char label,
+ struct GNUNET_REGEX_State *from_state, const char *label,
struct GNUNET_REGEX_State *to_state)
{
- int is_dup;
- struct Transition *t;
+ struct GNUNET_REGEX_Transition *t;
+ struct GNUNET_REGEX_Transition *oth;
if (NULL == from_state)
{
return;
}
- // Do not add duplicate state transitions
- is_dup = GNUNET_NO;
+ /* Do not add duplicate state transitions */
for (t = from_state->transitions_head; NULL != t; t = t->next)
{
- if (t->to_state == to_state && t->label == label &&
+ if (t->to_state == to_state && 0 == nullstrcmp (t->label, label) &&
t->from_state == from_state)
- {
- is_dup = GNUNET_YES;
- break;
- }
+ return;
}
- if (is_dup)
- return;
+ /* sort transitions by label */
+ for (oth = from_state->transitions_head; NULL != oth; oth = oth->next)
+ {
+ if (0 < nullstrcmp (oth->label, label))
+ break;
+ }
- t = GNUNET_malloc (sizeof (struct Transition));
- t->id = ctx->transition_id++;
- t->label = label;
+ t = GNUNET_malloc (sizeof (struct GNUNET_REGEX_Transition));
+ if (NULL != ctx)
+ t->id = ctx->transition_id++;
+ if (NULL != label)
+ t->label = GNUNET_strdup (label);
+ else
+ t->label = NULL;
t->to_state = to_state;
t->from_state = from_state;
- // Add outgoing transition to 'from_state'
+ /* Add outgoing transition to 'from_state' */
from_state->transition_count++;
- GNUNET_CONTAINER_DLL_insert (from_state->transitions_head,
- from_state->transitions_tail, t);
+ GNUNET_CONTAINER_DLL_insert_before (from_state->transitions_head,
+ from_state->transitions_tail, oth, t);
+}
+
+
+/**
+ * Remove a 'transition' from 'state'.
+ *
+ * @param state state from which the to-be-removed transition originates.
+ * @param transition transition that should be removed from state 'state'.
+ */
+static void
+state_remove_transition (struct GNUNET_REGEX_State *state,
+ struct GNUNET_REGEX_Transition *transition)
+{
+ if (NULL == state || NULL == transition)
+ return;
+
+ if (transition->from_state != state)
+ return;
+
+ GNUNET_free_non_null (transition->label);
+
+ state->transition_count--;
+ GNUNET_CONTAINER_DLL_remove (state->transitions_head, state->transitions_tail,
+ transition);
+
+ GNUNET_free (transition);
}
+
/**
* Compare two states. Used for sorting.
*
static int
state_compare (const void *a, const void *b)
{
- struct GNUNET_REGEX_State **s1;
- struct GNUNET_REGEX_State **s2;
-
- s1 = (struct GNUNET_REGEX_State **) a;
- s2 = (struct GNUNET_REGEX_State **) b;
+ struct GNUNET_REGEX_State **s1 = (struct GNUNET_REGEX_State **) a;
+ struct GNUNET_REGEX_State **s2 = (struct GNUNET_REGEX_State **) b;
return (*s1)->id - (*s2)->id;
}
+
/**
* Get all edges leaving state 's'.
*
* @param s state.
- * @param edges all edges leaving 's'.
+ * @param edges all edges leaving 's', expected to be allocated and have enough
+ * space for s->transitions_count elements.
*
* @return number of edges.
*/
static unsigned int
state_get_edges (struct GNUNET_REGEX_State *s, struct GNUNET_REGEX_Edge *edges)
{
- struct Transition *t;
+ struct GNUNET_REGEX_Transition *t;
unsigned int count;
if (NULL == s)
{
if (NULL != t->to_state)
{
- edges[count].label = &t->label;
+ edges[count].label = t->label;
edges[count].destination = t->to_state->hash;
count++;
}
return count;
}
+
/**
* 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.
+ * @return 0 if the sets are equal, otherwise non-zero
*/
static int
state_set_compare (struct GNUNET_REGEX_StateSet *sset1,
struct GNUNET_REGEX_StateSet *sset2)
{
int result;
- int i;
+ unsigned int i;
if (NULL == sset1 || NULL == sset2)
return 1;
- result = sset1->len - sset2->len;
-
- for (i = 0; i < sset1->len; i++)
- {
- if (0 != result)
+ result = sset1->off - sset2->off;
+ if (result < 0)
+ return -1;
+ if (result > 0)
+ return 1;
+ for (i = 0; i < sset1->off; i++)
+ if (0 != (result = state_compare (&sset1->states[i], &sset2->states[i])))
break;
-
- result = state_compare (&sset1->states[i], &sset2->states[i]);
- }
return result;
}
+
/**
* Clears the given StateSet 'set'
*
static void
state_set_clear (struct GNUNET_REGEX_StateSet *set)
{
- if (NULL != set)
- {
- if (NULL != set->states)
- GNUNET_free (set->states);
- GNUNET_free (set);
- }
+ GNUNET_array_grow (set->states, set->size, 0);
+ set->off = 0;
}
+
/**
* Clears an automaton fragment. Does not destroy the states inside the
* automaton.
GNUNET_free (a);
}
+
/**
* Frees the memory used by State 's'
*
static void
automaton_destroy_state (struct GNUNET_REGEX_State *s)
{
- struct Transition *t;
- struct Transition *next_t;
+ struct GNUNET_REGEX_Transition *t;
+ struct GNUNET_REGEX_Transition *next_t;
if (NULL == s)
return;
- if (NULL != s->name)
- GNUNET_free (s->name);
-
+ GNUNET_free_non_null (s->name);
+ GNUNET_free_non_null (s->proof);
+ state_set_clear (&s->nfa_set);
for (t = s->transitions_head; NULL != t; t = next_t)
{
next_t = t->next;
- GNUNET_CONTAINER_DLL_remove (s->transitions_head, s->transitions_tail, t);
- GNUNET_free (t);
+ state_remove_transition (s, t);
}
- state_set_clear (s->nfa_set);
-
GNUNET_free (s);
}
+
/**
* 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
automaton_remove_state (struct GNUNET_REGEX_Automaton *a,
struct GNUNET_REGEX_State *s)
{
- struct GNUNET_REGEX_State *ss;
struct GNUNET_REGEX_State *s_check;
- struct Transition *t_check;
+ struct GNUNET_REGEX_Transition *t_check;
+ struct GNUNET_REGEX_Transition *t_check_next;
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
+ /* 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)
+ t_check = t_check_next)
{
- if (t_check->to_state == ss)
- {
- GNUNET_CONTAINER_DLL_remove (s_check->transitions_head,
- s_check->transitions_tail, t_check);
- s_check->transition_count--;
- }
+ t_check_next = t_check->next;
+ if (t_check->to_state == s)
+ state_remove_transition (s_check, t_check);
}
}
- automaton_destroy_state (ss);
+ /* remove state */
+ GNUNET_CONTAINER_DLL_remove (a->states_head, a->states_tail, s);
+ a->state_count--;
+
+ automaton_destroy_state (s);
}
+
/**
* Merge two states into one. Will merge 's1' and 's2' into 's1' and destroy
- * 's2'.
+ * 's2'. 's1' will contain all (non-duplicate) outgoing transitions of 's2'.
*
* @param ctx context
* @param a automaton
struct GNUNET_REGEX_State *s2)
{
struct GNUNET_REGEX_State *s_check;
- struct Transition *t_check;
- char *new_name;
+ struct GNUNET_REGEX_Transition *t_check;
+ struct GNUNET_REGEX_Transition *t;
+ struct GNUNET_REGEX_Transition *t_next;
+ int is_dup;
- GNUNET_assert (NULL != ctx && NULL != a && NULL != s1 && NULL != s2);
+ if (s1 == s2)
+ return;
- // 1. Make all transitions pointing to s2 point to s1
+ /* 1. Make all transitions pointing to s2 point to s1, unless this transition
+ * does not already exists, if it already exists remove transition. */
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)
+ for (t_check = s_check->transitions_head; NULL != t_check; t_check = t_next)
{
+ t_next = t_check->next;
+
if (s2 == t_check->to_state)
- t_check->to_state = s1;
+ {
+ is_dup = GNUNET_NO;
+ for (t = t_check->from_state->transitions_head; NULL != t; t = t->next)
+ {
+ if (t->to_state == s1 && 0 == strcmp (t_check->label, t->label))
+ is_dup = GNUNET_YES;
+ }
+ if (GNUNET_NO == is_dup)
+ t_check->to_state = s1;
+ else
+ state_remove_transition (t_check->from_state, t_check);
+ }
}
}
- // 2. Add all transitions from s2 to sX to s1
+ /* 2. Add all transitions from s2 to sX to s1 */
for (t_check = s2->transitions_head; NULL != t_check; t_check = t_check->next)
{
if (t_check->to_state != s1)
state_add_transition (ctx, s1, t_check->label, t_check->to_state);
}
- // 3. Rename s1 to {s1,s2}
- new_name = GNUNET_strdup (s1->name);
- if (NULL != s1->name)
- {
- GNUNET_free (s1->name);
- s1->name = NULL;
- }
+ /* 3. Rename s1 to {s1,s2} */
+#if REGEX_DEBUG_DFA
+ char *new_name;
+
+ new_name = s1->name;
GNUNET_asprintf (&s1->name, "{%s,%s}", new_name, s2->name);
GNUNET_free (new_name);
+#endif
- // remove state
+ /* remove state */
GNUNET_CONTAINER_DLL_remove (a->states_head, a->states_tail, s2);
a->state_count--;
automaton_destroy_state (s2);
}
+
/**
* Add a state to the automaton 'a', always use this function to alter the
* states DLL of the automaton.
a->state_count++;
}
-typedef void (*GNUNET_REGEX_traverse_action) (void *cls,
- struct GNUNET_REGEX_State * s);
-
-static void
-automaton_state_traverse_backward (void *cls, struct GNUNET_REGEX_State *s,
- GNUNET_REGEX_traverse_action action)
-{
-
- GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Traversing backwards...\n");
-
-}
/**
- * Traverses all states that are reachable from state 's'. Expects the states to
- * be unmarked (s->marked == GNUNET_NO). Performs 'action' on each visited
- * state.
+ * Depth-first traversal (DFS) of all states that are reachable from state
+ * 's'. Performs 'action' on each visited state.
*
- * @param cls closure.
* @param s start state.
+ * @param marks an array of size a->state_count to remember which state was
+ * already visited.
+ * @param count current count of the state.
+ * @param check function that is checked before advancing on each transition
+ * in the DFS.
+ * @param check_cls closure for check.
* @param action action to be performed on each state.
+ * @param action_cls closure for action.
*/
static void
-automaton_state_traverse (void *cls, struct GNUNET_REGEX_State *s,
- GNUNET_REGEX_traverse_action action)
+automaton_state_traverse (struct GNUNET_REGEX_State *s, int *marks,
+ unsigned int *count,
+ GNUNET_REGEX_traverse_check check, void *check_cls,
+ GNUNET_REGEX_traverse_action action, void *action_cls)
{
- struct Transition *t;
+ struct GNUNET_REGEX_Transition *t;
- if (GNUNET_NO == s->marked)
- {
- s->marked = GNUNET_YES;
+ if (GNUNET_YES == marks[s->traversal_id])
+ return;
- if (NULL != action)
- action (cls, s);
+ marks[s->traversal_id] = GNUNET_YES;
- for (t = s->transitions_head; NULL != t; t = t->next)
- automaton_state_traverse (cls, t->to_state, action);
+ if (NULL != action)
+ action (action_cls, *count, s);
+
+ (*count)++;
+
+ for (t = s->transitions_head; NULL != t; t = t->next)
+ {
+ if (NULL == check ||
+ (NULL != check && GNUNET_YES == check (check_cls, s, t)))
+ {
+ automaton_state_traverse (t->to_state, marks, count, check, check_cls,
+ action, action_cls);
+ }
}
}
+
/**
- * Traverses the given automaton from it's start state, visiting all reachable
- * states and calling 'action' on each one of them.
+ * Traverses the given automaton using depth-first-search (DFS) from it's start
+ * state, visiting all reachable states and calling 'action' on each one of
+ * them.
*
- * @param cls closure.
- * @param a automaton.
+ * @param a automaton to be traversed.
+ * @param start start state, pass a->start or NULL to traverse the whole automaton.
+ * @param check function that is checked before advancing on each transition
+ * in the DFS.
+ * @param check_cls closure for check.
* @param action action to be performed on each state.
+ * @param action_cls closure for action
*/
-static void
-automaton_traverse (void *cls, struct GNUNET_REGEX_Automaton *a,
- GNUNET_REGEX_traverse_action action)
+void
+GNUNET_REGEX_automaton_traverse (const struct GNUNET_REGEX_Automaton *a,
+ struct GNUNET_REGEX_State *start,
+ GNUNET_REGEX_traverse_check check,
+ void *check_cls,
+ GNUNET_REGEX_traverse_action action,
+ void *action_cls)
{
+ unsigned int count;
struct GNUNET_REGEX_State *s;
- for (s = a->start; NULL != s; s = s->next)
- s->marked = GNUNET_NO;
+ if (NULL == a || 0 == a->state_count)
+ return;
+
+ int marks[a->state_count];
+
+ for (count = 0, s = a->states_head; NULL != s && count < a->state_count;
+ s = s->next, count++)
+ {
+ s->traversal_id = count;
+ marks[s->traversal_id] = GNUNET_NO;
+ }
+
+ count = 0;
+
+ if (NULL == start)
+ s = a->start;
+ else
+ s = start;
+
+ automaton_state_traverse (s, marks, &count, check, check_cls, action,
+ action_cls);
+}
+
+
+/**
+ * String container for faster string operations.
+ */
+struct StringBuffer
+{
+ /**
+ * Buffer holding the string (may start in the middle!);
+ * NOT 0-terminated!
+ */
+ char *sbuf;
+
+ /**
+ * Allocated buffer.
+ */
+ char *abuf;
+
+ /**
+ * Length of the string in the buffer.
+ */
+ size_t slen;
+
+ /**
+ * Number of bytes allocated for 'sbuf'
+ */
+ unsigned int blen;
+
+ /**
+ * Buffer currently represents "NULL" (not the empty string!)
+ */
+ int16_t null_flag;
+
+ /**
+ * If this entry is part of the last/current generation array,
+ * this flag is GNUNET_YES if the last and current generation are
+ * identical (and thus copying is unnecessary if the value didn't
+ * change). This is used in an optimization that improves
+ * performance by about 1% --- if we use int16_t here. With just
+ * "int" for both flags, performance drops (on my system) significantly,
+ * most likely due to increased cache misses.
+ */
+ int16_t synced;
+
+};
+
+
+/**
+ * Compare two strings for equality. If either is NULL they are not equal.
+ *
+ * @param s1 first string for comparison.
+ * @param s2 second string for comparison.
+ *
+ * @return 0 if the strings are the same or both NULL, 1 or -1 if not.
+ */
+static int
+sb_nullstrcmp (const struct StringBuffer *s1,
+ const struct StringBuffer *s2)
+{
+ if ( (GNUNET_YES == s1->null_flag) &&
+ (GNUNET_YES == s2->null_flag) )
+ return 0;
+ if ( (GNUNET_YES == s1->null_flag) ||
+ (GNUNET_YES == s2->null_flag) )
+ return -1;
+ if (s1->slen != s2->slen)
+ return -1;
+ return memcmp (s1->sbuf, s2->sbuf, s1->slen);
+}
+
+
+/**
+ * Compare two strings for equality.
+ *
+ * @param s1 first string for comparison.
+ * @param s2 second string for comparison.
+ *
+ * @return 0 if the strings are the same, 1 or -1 if not.
+ */
+static int
+sb_strcmp (const struct StringBuffer *s1,
+ const struct StringBuffer *s2)
+{
+ if (s1->slen != s2->slen)
+ return -1;
+ return memcmp (s1->sbuf, s2->sbuf, s1->slen);
+}
+
+
+/**
+ * Reallocate the buffer of 'ret' to fit 'nlen' characters;
+ * move the existing string to the beginning of the new buffer.
+ *
+ * @param ret current buffer, to be updated
+ * @param nlen target length for the buffer, must be at least ret->slen
+ */
+static void
+sb_realloc (struct StringBuffer *ret,
+ size_t nlen)
+{
+ char *old;
+
+ GNUNET_assert (nlen >= ret->slen);
+ old = ret->abuf;
+ ret->abuf = GNUNET_malloc (nlen);
+ ret->blen = nlen;
+ memcpy (ret->abuf,
+ ret->sbuf,
+ ret->slen);
+ ret->sbuf = ret->abuf;
+ GNUNET_free_non_null (old);
+}
+
+
+/**
+ * Append a string.
+ *
+ * @param ret where to write the result
+ * @param sarg string to append
+ */
+static void
+sb_append (struct StringBuffer *ret,
+ const struct StringBuffer *sarg)
+{
+ if (GNUNET_YES == ret->null_flag)
+ ret->slen = 0;
+ ret->null_flag = GNUNET_NO;
+ if (ret->blen < sarg->slen + ret->slen)
+ sb_realloc (ret, ret->blen + sarg->slen + 128);
+ memcpy (&ret->sbuf[ret->slen],
+ sarg->sbuf,
+ sarg->slen);
+ ret->slen += sarg->slen;
+}
+
+
+/**
+ * Append a C string.
+ *
+ * @param ret where to write the result
+ * @param cstr string to append
+ */
+static void
+sb_append_cstr (struct StringBuffer *ret,
+ const char *cstr)
+{
+ size_t cstr_len = strlen (cstr);
+
+ if (GNUNET_YES == ret->null_flag)
+ ret->slen = 0;
+ ret->null_flag = GNUNET_NO;
+ if (ret->blen < cstr_len + ret->slen)
+ sb_realloc (ret, ret->blen + cstr_len + 128);
+ memcpy (&ret->sbuf[ret->slen],
+ cstr,
+ cstr_len);
+ ret->slen += cstr_len;
+}
+
+
+/**
+ * Wrap a string buffer, that is, set ret to the format string
+ * which contains an "%s" which is to be replaced with the original
+ * content of 'ret'. Note that optimizing this function is not
+ * really worth it, it is rarely called.
+ *
+ * @param ret where to write the result and take the input for %.*s from
+ * @param format format string, fprintf-style, with exactly one "%.*s"
+ * @param extra_chars how long will the result be, in addition to 'sarg' length
+ */
+static void
+sb_wrap (struct StringBuffer *ret,
+ const char *format,
+ size_t extra_chars)
+{
+ char *temp;
+
+ if (GNUNET_YES == ret->null_flag)
+ ret->slen = 0;
+ ret->null_flag = GNUNET_NO;
+ temp = GNUNET_malloc (ret->slen + extra_chars + 1);
+ GNUNET_snprintf (temp,
+ ret->slen + extra_chars + 1,
+ format,
+ (int) ret->slen,
+ ret->sbuf);
+ GNUNET_free_non_null (ret->abuf);
+ ret->abuf = temp;
+ ret->sbuf = temp;
+ ret->blen = ret->slen + extra_chars + 1;
+ ret->slen = ret->slen + extra_chars;
+}
+
+
+/**
+ * Format a string buffer. Note that optimizing this function is not
+ * really worth it, it is rarely called.
+ *
+ * @param ret where to write the result
+ * @param format format string, fprintf-style, with exactly one "%.*s"
+ * @param extra_chars how long will the result be, in addition to 'sarg' length
+ * @param sarg string to print into the format
+ */
+static void
+sb_printf1 (struct StringBuffer *ret,
+ const char *format,
+ size_t extra_chars,
+ const struct StringBuffer *sarg)
+{
+ if (ret->blen < sarg->slen + extra_chars + 1)
+ sb_realloc (ret,
+ sarg->slen + extra_chars + 1);
+ ret->null_flag = GNUNET_NO;
+ ret->sbuf = ret->abuf;
+ ret->slen = sarg->slen + extra_chars;
+ GNUNET_snprintf (ret->sbuf,
+ ret->blen,
+ format,
+ (int) sarg->slen,
+ sarg->sbuf);
+}
+
+
+/**
+ * Format a string buffer.
+ *
+ * @param ret where to write the result
+ * @param format format string, fprintf-style, with exactly two "%.*s"
+ * @param extra_chars how long will the result be, in addition to 'sarg1/2' length
+ * @param sarg1 first string to print into the format
+ * @param sarg2 second string to print into the format
+ */
+static void
+sb_printf2 (struct StringBuffer *ret,
+ const char *format,
+ size_t extra_chars,
+ const struct StringBuffer *sarg1,
+ const struct StringBuffer *sarg2)
+{
+ if (ret->blen < sarg1->slen + sarg2->slen + extra_chars + 1)
+ sb_realloc (ret,
+ sarg1->slen + sarg2->slen + extra_chars + 1);
+ ret->null_flag = GNUNET_NO;
+ ret->slen = sarg1->slen + sarg2->slen + extra_chars;
+ ret->sbuf = ret->abuf;
+ GNUNET_snprintf (ret->sbuf,
+ ret->blen,
+ format,
+ (int) sarg1->slen,
+ sarg1->sbuf,
+ (int) sarg2->slen,
+ sarg2->sbuf);
+}
- automaton_state_traverse (cls, a->start, action);
+
+/**
+ * Format a string buffer. Note that optimizing this function is not
+ * really worth it, it is rarely called.
+ *
+ * @param ret where to write the result
+ * @param format format string, fprintf-style, with exactly three "%.*s"
+ * @param extra_chars how long will the result be, in addition to 'sarg1/2/3' length
+ * @param sarg1 first string to print into the format
+ * @param sarg2 second string to print into the format
+ * @param sarg3 third string to print into the format
+ */
+static void
+sb_printf3 (struct StringBuffer *ret,
+ const char *format,
+ size_t extra_chars,
+ const struct StringBuffer *sarg1,
+ const struct StringBuffer *sarg2,
+ const struct StringBuffer *sarg3)
+{
+ if (ret->blen < sarg1->slen + sarg2->slen + sarg3->slen + extra_chars + 1)
+ sb_realloc (ret,
+ sarg1->slen + sarg2->slen + sarg3->slen + extra_chars + 1);
+ ret->null_flag = GNUNET_NO;
+ ret->slen = sarg1->slen + sarg2->slen + sarg3->slen + extra_chars;
+ ret->sbuf = ret->abuf;
+ GNUNET_snprintf (ret->sbuf,
+ ret->blen,
+ format,
+ (int) sarg1->slen,
+ sarg1->sbuf,
+ (int) sarg2->slen,
+ sarg2->sbuf,
+ (int) sarg3->slen,
+ sarg3->sbuf);
+}
+
+
+/**
+ * Free resources of the given string buffer.
+ *
+ * @param sb buffer to free (actual pointer is not freed, as they
+ * should not be individually allocated)
+ */
+static void
+sb_free (struct StringBuffer *sb)
+{
+ GNUNET_array_grow (sb->abuf,
+ sb->blen,
+ 0);
+ sb->slen = 0;
+ sb->sbuf = NULL;
+ sb->null_flag= GNUNET_YES;
+}
+
+
+/**
+ * Copy the given string buffer from 'in' to 'out'.
+ *
+ * @param in input string
+ * @param out output string
+ */
+static void
+sb_strdup (struct StringBuffer *out,
+ const struct StringBuffer *in)
+
+{
+ out->null_flag = in->null_flag;
+ if (GNUNET_YES == out->null_flag)
+ return;
+ if (out->blen < in->slen)
+ {
+ GNUNET_array_grow (out->abuf,
+ out->blen,
+ in->slen);
+ }
+ out->sbuf = out->abuf;
+ out->slen = in->slen;
+ memcpy (out->sbuf, in->sbuf, out->slen);
+}
+
+
+/**
+ * Copy the given string buffer from 'in' to 'out'.
+ *
+ * @param cstr input string
+ * @param out output string
+ */
+static void
+sb_strdup_cstr (struct StringBuffer *out,
+ const char *cstr)
+{
+ if (NULL == cstr)
+ {
+ out->null_flag = GNUNET_YES;
+ return;
+ }
+ out->null_flag = GNUNET_NO;
+ out->slen = strlen (cstr);
+ if (out->blen < out->slen)
+ {
+ GNUNET_array_grow (out->abuf,
+ out->blen,
+ out->slen);
+ }
+ out->sbuf = out->abuf;
+ memcpy (out->sbuf, cstr, out->slen);
+}
+
+
+/**
+ * Check if the given string 'str' needs parentheses around it when
+ * using it to generate a regex.
+ *
+ * @param str string
+ *
+ * @return GNUNET_YES if parentheses are needed, GNUNET_NO otherwise
+ */
+static int
+needs_parentheses (const struct StringBuffer *str)
+{
+ size_t slen;
+ const char *op;
+ const char *cl;
+ const char *pos;
+ const char *end;
+ unsigned int cnt;
+
+ if ((GNUNET_YES == str->null_flag) || ((slen = str->slen) < 2))
+ return GNUNET_NO;
+ pos = str->sbuf;
+ if ('(' != pos[0])
+ return GNUNET_YES;
+ end = str->sbuf + slen;
+ cnt = 1;
+ pos++;
+ while (cnt > 0)
+ {
+ cl = memchr (pos, ')', end - pos);
+ if (NULL == cl)
+ {
+ GNUNET_break (0);
+ return GNUNET_YES;
+ }
+ /* while '(' before ')', count opening parens */
+ while ( (NULL != (op = memchr (pos, '(', end - pos))) &&
+ (op < cl) )
+ {
+ cnt++;
+ pos = op + 1;
+ }
+ /* got ')' first */
+ cnt--;
+ pos = cl + 1;
+ }
+ return (*pos == '\0') ? GNUNET_NO : GNUNET_YES;
}
+
+/**
+ * Remove parentheses surrounding string 'str'.
+ * Example: "(a)" becomes "a", "(a|b)|(a|c)" stays the same.
+ * You need to GNUNET_free the returned string.
+ *
+ * @param str string, modified to contain a
+ * @return string without surrounding parentheses, string 'str' if no preceding
+ * epsilon could be found, NULL if 'str' was NULL
+ */
+static void
+remove_parentheses (struct StringBuffer *str)
+{
+ size_t slen;
+ const char *pos;
+ const char *end;
+ const char *sbuf;
+ const char *op;
+ const char *cp;
+ unsigned int cnt;
+
+ if (0)
+ return;
+ sbuf = str->sbuf;
+ if ( (GNUNET_YES == str->null_flag) ||
+ (1 >= (slen = str->slen)) ||
+ ('(' != str->sbuf[0]) ||
+ (')' != str->sbuf[slen - 1]) )
+ return;
+ cnt = 0;
+ pos = &sbuf[1];
+ end = &sbuf[slen - 1];
+ op = memchr (pos, '(', end - pos);
+ cp = memchr (pos, ')', end - pos);
+ while (NULL != cp)
+ {
+ while ( (NULL != op) &&
+ (op < cp) )
+ {
+ cnt++;
+ pos = op + 1;
+ op = memchr (pos, '(', end - pos);
+ }
+ while ( (NULL != cp) &&
+ ( (NULL == op) ||
+ (cp < op) ) )
+ {
+ if (0 == cnt)
+ return; /* can't strip parens */
+ cnt--;
+ pos = cp + 1;
+ cp = memchr (pos, ')', end - pos);
+ }
+ }
+ if (0 != cnt)
+ {
+ GNUNET_break (0);
+ return;
+ }
+ str->sbuf++;
+ str->slen -= 2;
+}
+
+
+/**
+ * Check if the string 'str' starts with an epsilon (empty string).
+ * Example: "(|a)" is starting with an epsilon.
+ *
+ * @param str string to test
+ *
+ * @return 0 if str has no epsilon, 1 if str starts with '(|' and ends with ')'
+ */
+static int
+has_epsilon (const struct StringBuffer *str)
+{
+ return
+ (GNUNET_YES != str->null_flag) &&
+ (0 < str->slen) &&
+ ('(' == str->sbuf[0]) &&
+ ('|' == str->sbuf[1]) &&
+ (')' == str->sbuf[str->slen - 1]);
+}
+
+
+/**
+ * Remove an epsilon from the string str. Where epsilon is an empty string
+ * Example: str = "(|a|b|c)", result: "a|b|c"
+ * The returned string needs to be freed.
+ *
+ * @param str original string
+ * @param ret where to return string without preceding epsilon, string 'str' if no preceding
+ * epsilon could be found, NULL if 'str' was NULL
+ */
+static void
+remove_epsilon (const struct StringBuffer *str,
+ struct StringBuffer *ret)
+{
+ if (GNUNET_YES == str->null_flag)
+ {
+ ret->null_flag = GNUNET_YES;
+ return;
+ }
+ if ( (str->slen > 1) &&
+ ('(' == str->sbuf[0]) &&
+ ('|' == str->sbuf[1]) &&
+ (')' == str->sbuf[str->slen - 1]) )
+ {
+ /* remove epsilon */
+ if (ret->blen < str->slen - 3)
+ {
+ GNUNET_array_grow (ret->abuf,
+ ret->blen,
+ str->slen - 3);
+ }
+ ret->sbuf = ret->abuf;
+ ret->slen = str->slen - 3;
+ memcpy (ret->sbuf, &str->sbuf[2], ret->slen);
+ return;
+ }
+ sb_strdup (ret, str);
+}
+
+
+/**
+ * Compare n bytes of 'str1' and 'str2'
+ *
+ * @param str1 first string to compare
+ * @param str2 second string for comparison
+ * @param n number of bytes to compare
+ *
+ * @return -1 if any of the strings is NULL, 0 if equal, non 0 otherwise
+ */
+static int
+sb_strncmp (const struct StringBuffer *str1,
+ const struct StringBuffer *str2, size_t n)
+{
+ size_t max;
+
+ if ( (str1->slen != str2->slen) &&
+ ( (str1->slen < n) ||
+ (str2->slen < n) ) )
+ return -1;
+ max = GNUNET_MAX (str1->slen, str2->slen);
+ if (max > n)
+ max = n;
+ return memcmp (str1->sbuf, str2->sbuf, max);
+}
+
+
+/**
+ * Compare n bytes of 'str1' and 'str2'
+ *
+ * @param str1 first string to compare
+ * @param str2 second C string for comparison
+ * @param n number of bytes to compare (and length of str2)
+ *
+ * @return -1 if any of the strings is NULL, 0 if equal, non 0 otherwise
+ */
+static int
+sb_strncmp_cstr (const struct StringBuffer *str1,
+ const char *str2, size_t n)
+{
+ if (str1->slen < n)
+ return -1;
+ return memcmp (str1->sbuf, str2, n);
+}
+
+
+/**
+ * Initialize string buffer for storing strings of up to n
+ * characters.
+ *
+ * @param sb buffer to initialize
+ * @param n desired target length
+ */
+static void
+sb_init (struct StringBuffer *sb,
+ size_t n)
+{
+ sb->null_flag = GNUNET_NO;
+ sb->abuf = sb->sbuf = (0 == n) ? NULL : GNUNET_malloc (n);
+ sb->blen = n;
+ sb->slen = 0;
+}
+
+
+/**
+ * Compare 'str1', starting from position 'k', with whole 'str2'
+ *
+ * @param str1 first string to compare, starting from position 'k'
+ * @param str2 second string for comparison
+ * @param k starting position in 'str1'
+ *
+ * @return -1 if any of the strings is NULL, 0 if equal, non 0 otherwise
+ */
+static int
+sb_strkcmp (const struct StringBuffer *str1,
+ const struct StringBuffer *str2, size_t k)
+{
+ if ( (GNUNET_YES == str1->null_flag) ||
+ (GNUNET_YES == str2->null_flag) ||
+ (k > str1->slen) ||
+ (str1->slen - k != str2->slen) )
+ return -1;
+ return memcmp (&str1->sbuf[k], str2->sbuf, str2->slen);
+}
+
+
+/**
+ * Helper function used as 'action' in 'GNUNET_REGEX_automaton_traverse'
+ * function to create the depth-first numbering of the states.
+ *
+ * @param cls states array.
+ * @param count current state counter.
+ * @param s current state.
+ */
+static void
+number_states (void *cls, const unsigned int count,
+ struct GNUNET_REGEX_State *s)
+{
+ struct GNUNET_REGEX_State **states = cls;
+
+ s->dfs_id = count;
+ if (NULL != states)
+ states[count] = s;
+}
+
+
+
+#define PRIS(a) \
+ ((GNUNET_YES == a.null_flag) ? 6 : (int) a.slen), \
+ ((GNUNET_YES == a.null_flag) ? "(null)" : a.sbuf)
+
+
+/**
+ * Construct the regular expression given the inductive step,
+ * $R^{(k)}_{ij} = R^{(k-1)}_{ij} | R^{(k-1)}_{ik} ( R^{(k-1)}_{kk} )^*
+ * R^{(k-1)}_{kj}, and simplify the resulting expression saved in R_cur_ij.
+ *
+ * @param R_last_ij value of $R^{(k-1)_{ij}.
+ * @param R_last_ik value of $R^{(k-1)_{ik}.
+ * @param R_last_kk value of $R^{(k-1)_{kk}.
+ * @param R_last_kj value of $R^{(k-1)_{kj}.
+ * @param R_cur_ij result for this inductive step is saved in R_cur_ij, R_cur_ij
+ * is expected to be NULL when called!
+ * @param R_cur_l optimization -- kept between iterations to avoid realloc
+ * @param R_cur_r optimization -- kept between iterations to avoid realloc
+ */
+static void
+automaton_create_proofs_simplify (const struct StringBuffer *R_last_ij,
+ const struct StringBuffer *R_last_ik,
+ const struct StringBuffer *R_last_kk,
+ const struct StringBuffer *R_last_kj,
+ struct StringBuffer *R_cur_ij,
+ struct StringBuffer *R_cur_l,
+ struct StringBuffer *R_cur_r)
+{
+ struct StringBuffer R_temp_ij;
+ struct StringBuffer R_temp_ik;
+ struct StringBuffer R_temp_kj;
+ struct StringBuffer R_temp_kk;
+ int eps_check;
+ int ij_ik_cmp;
+ int ij_kj_cmp;
+ int ik_kk_cmp;
+ int kk_kj_cmp;
+ int clean_ik_kk_cmp;
+ int clean_kk_kj_cmp;
+ size_t length;
+ size_t length_l;
+ size_t length_r;
+
+ /*
+ * $R^{(k)}_{ij} = R^{(k-1)}_{ij} | R^{(k-1)}_{ik} ( R^{(k-1)}_{kk} )^* R^{(k-1)}_{kj}
+ * R_last == R^{(k-1)}, R_cur == R^{(k)}
+ * R_cur_ij = R_cur_l | R_cur_r
+ * R_cur_l == R^{(k-1)}_{ij}
+ * R_cur_r == R^{(k-1)}_{ik} ( R^{(k-1)}_{kk} )^* R^{(k-1)}_{kj}
+ */
+
+ if ( (GNUNET_YES == R_last_ij->null_flag) &&
+ ( (GNUNET_YES == R_last_ik->null_flag) ||
+ (GNUNET_YES == R_last_kj->null_flag)))
+ {
+ /* R^{(k)}_{ij} = N | N */
+ R_cur_ij->null_flag = GNUNET_YES;
+ R_cur_ij->synced = GNUNET_NO;
+ return;
+ }
+
+ if ( (GNUNET_YES == R_last_ik->null_flag) ||
+ (GNUNET_YES == R_last_kj->null_flag) )
+ {
+ /* R^{(k)}_{ij} = R^{(k-1)}_{ij} | N */
+ if (GNUNET_YES == R_last_ij->synced)
+ {
+ R_cur_ij->synced = GNUNET_YES;
+ R_cur_ij->null_flag = GNUNET_NO;
+ return;
+ }
+ R_cur_ij->synced = GNUNET_YES;
+ sb_strdup (R_cur_ij, R_last_ij);
+ return;
+ }
+ R_cur_ij->synced = GNUNET_NO;
+
+ /* $R^{(k)}_{ij} = N | R^{(k-1)}_{ik} ( R^{(k-1)}_{kk} )^* R^{(k-1)}_{kj} OR
+ * $R^{(k)}_{ij} = R^{(k-1)}_{ij} | R^{(k-1)}_{ik} ( R^{(k-1)}_{kk} )^* R^{(k-1)}_{kj} */
+
+ R_cur_r->null_flag = GNUNET_YES;
+ R_cur_r->slen = 0;
+ R_cur_l->null_flag = GNUNET_YES;
+ R_cur_l->slen = 0;
+
+ /* cache results from strcmp, we might need these many times */
+ ij_kj_cmp = sb_nullstrcmp (R_last_ij, R_last_kj);
+ ij_ik_cmp = sb_nullstrcmp (R_last_ij, R_last_ik);
+ ik_kk_cmp = sb_nullstrcmp (R_last_ik, R_last_kk);
+ kk_kj_cmp = sb_nullstrcmp (R_last_kk, R_last_kj);
+
+ /* Assign R_temp_(ik|kk|kj) to R_last[][] and remove epsilon as well
+ * as parentheses, so we can better compare the contents */
+
+ memset (&R_temp_ij, 0, sizeof (struct StringBuffer));
+ memset (&R_temp_ik, 0, sizeof (struct StringBuffer));
+ memset (&R_temp_kk, 0, sizeof (struct StringBuffer));
+ memset (&R_temp_kj, 0, sizeof (struct StringBuffer));
+ remove_epsilon (R_last_ik, &R_temp_ik);
+ remove_epsilon (R_last_kk, &R_temp_kk);
+ remove_epsilon (R_last_kj, &R_temp_kj);
+ remove_parentheses (&R_temp_ik);
+ remove_parentheses (&R_temp_kk);
+ remove_parentheses (&R_temp_kj);
+ clean_ik_kk_cmp = sb_nullstrcmp (R_last_ik, &R_temp_kk);
+ clean_kk_kj_cmp = sb_nullstrcmp (&R_temp_kk, R_last_kj);
+
+ /* construct R_cur_l (and, if necessary R_cur_r) */
+ if (GNUNET_YES != R_last_ij->null_flag)
+ {
+ /* Assign R_temp_ij to R_last_ij and remove epsilon as well
+ * as parentheses, so we can better compare the contents */
+ remove_epsilon (R_last_ij, &R_temp_ij);
+ remove_parentheses (&R_temp_ij);
+
+ if ( (0 == sb_strcmp (&R_temp_ij, &R_temp_ik)) &&
+ (0 == sb_strcmp (&R_temp_ik, &R_temp_kk)) &&
+ (0 == sb_strcmp (&R_temp_kk, &R_temp_kj)) )
+ {
+ if (0 == R_temp_ij.slen)
+ {
+ R_cur_r->null_flag = GNUNET_NO;
+ }
+ else if ((0 == sb_strncmp_cstr (R_last_ij, "(|", 2)) ||
+ (0 == sb_strncmp_cstr (R_last_ik, "(|", 2) &&
+ 0 == sb_strncmp_cstr (R_last_kj, "(|", 2)))
+ {
+ /*
+ * a|(e|a)a*(e|a) = a*
+ * a|(e|a)(e|a)*(e|a) = a*
+ * (e|a)|aa*a = a*
+ * (e|a)|aa*(e|a) = a*
+ * (e|a)|(e|a)a*a = a*
+ * (e|a)|(e|a)a*(e|a) = a*
+ * (e|a)|(e|a)(e|a)*(e|a) = a*
+ */
+ if (GNUNET_YES == needs_parentheses (&R_temp_ij))
+ sb_printf1 (R_cur_r, "(%.*s)*", 3, &R_temp_ij);
+ else
+ sb_printf1 (R_cur_r, "%.*s*", 1, &R_temp_ij);
+ }
+ else
+ {
+ /*
+ * a|aa*a = a+
+ * a|(e|a)a*a = a+
+ * a|aa*(e|a) = a+
+ * a|(e|a)(e|a)*a = a+
+ * a|a(e|a)*(e|a) = a+
+ */
+ if (GNUNET_YES == needs_parentheses (&R_temp_ij))
+ sb_printf1 (R_cur_r, "(%.*s)+", 3, &R_temp_ij);
+ else
+ sb_printf1 (R_cur_r, "%.*s+", 1, &R_temp_ij);
+ }
+ }
+ else if ( (0 == ij_ik_cmp) && (0 == clean_kk_kj_cmp) && (0 != clean_ik_kk_cmp) )
+ {
+ /* a|ab*b = ab* */
+ if (0 == R_last_kk->slen)
+ sb_strdup (R_cur_r, R_last_ij);
+ else if (GNUNET_YES == needs_parentheses (&R_temp_kk))
+ sb_printf2 (R_cur_r, "%.*s(%.*s)*", 3, R_last_ij, &R_temp_kk);
+ else
+ sb_printf2 (R_cur_r, "%.*s%.*s*", 1, R_last_ij, R_last_kk);
+ R_cur_l->null_flag = GNUNET_YES;
+ }
+ else if ( (0 == ij_kj_cmp) && (0 == clean_ik_kk_cmp) && (0 != clean_kk_kj_cmp))
+ {
+ /* a|bb*a = b*a */
+ if (R_last_kk->slen < 1)
+ {
+ sb_strdup (R_cur_r, R_last_kj);
+ }
+ else if (GNUNET_YES == needs_parentheses (&R_temp_kk))
+ sb_printf2 (R_cur_r, "(%.*s)*%.*s", 3, &R_temp_kk, R_last_kj);
+ else
+ sb_printf2 (R_cur_r, "%.*s*%.*s", 1, &R_temp_kk, R_last_kj);
+
+ R_cur_l->null_flag = GNUNET_YES;
+ }
+ else if ( (0 == ij_ik_cmp) && (0 == kk_kj_cmp) && (! has_epsilon (R_last_ij)) &&
+ has_epsilon (R_last_kk))
+ {
+ /* a|a(e|b)*(e|b) = a|ab* = a|a|ab|abb|abbb|... = ab* */
+ if (needs_parentheses (&R_temp_kk))
+ sb_printf2 (R_cur_r, "%.*s(%.*s)*", 3, R_last_ij, &R_temp_kk);
+ else
+ sb_printf2 (R_cur_r, "%.*s%.*s*", 1, R_last_ij, &R_temp_kk);
+ R_cur_l->null_flag = GNUNET_YES;
+ }
+ else if ( (0 == ij_kj_cmp) && (0 == ik_kk_cmp) && (! has_epsilon (R_last_ij)) &&
+ has_epsilon (R_last_kk))
+ {
+ /* a|(e|b)(e|b)*a = a|b*a = a|a|ba|bba|bbba|... = b*a */
+ if (needs_parentheses (&R_temp_kk))
+ sb_printf2 (R_cur_r, "(%.*s)*%.*s", 3, &R_temp_kk, R_last_ij);
+ else
+ sb_printf2 (R_cur_r, "%.*s*%.*s", 1, &R_temp_kk, R_last_ij);
+ R_cur_l->null_flag = GNUNET_YES;
+ }
+ else
+ {
+ sb_strdup (R_cur_l, R_last_ij);
+ remove_parentheses (R_cur_l);
+ }
+ }
+ else
+ {
+ /* we have no left side */
+ R_cur_l->null_flag = GNUNET_YES;
+ }
+
+ /* construct R_cur_r, if not already constructed */
+ if (GNUNET_YES == R_cur_r->null_flag)
+ {
+ length = R_temp_kk.slen - R_last_ik->slen;
+
+ /* a(ba)*bx = (ab)+x */
+ if ( (length > 0) &&
+ (GNUNET_YES != R_last_kk->null_flag) &&
+ (0 < R_last_kk->slen) &&
+ (GNUNET_YES != R_last_kj->null_flag) &&
+ (0 < R_last_kj->slen) &&
+ (GNUNET_YES != R_last_ik->null_flag) &&
+ (0 < R_last_ik->slen) &&
+ (0 == sb_strkcmp (&R_temp_kk, R_last_ik, length)) &&
+ (0 == sb_strncmp (&R_temp_kk, R_last_kj, length)) )
+ {
+ struct StringBuffer temp_a;
+ struct StringBuffer temp_b;
+
+ sb_init (&temp_a, length);
+ sb_init (&temp_b, R_last_kj->slen - length);
+
+ length_l = length;
+ temp_a.sbuf = temp_a.abuf;
+ memcpy (temp_a.sbuf, R_last_kj->sbuf, length_l);
+ temp_a.slen = length_l;
+
+ length_r = R_last_kj->slen - length;
+ temp_b.sbuf = temp_b.abuf;
+ memcpy (temp_b.sbuf, &R_last_kj->sbuf[length], length_r);
+ temp_b.slen = length_r;
+
+ /* e|(ab)+ = (ab)* */
+ if ( (GNUNET_YES != R_cur_l->null_flag) &&
+ (0 == R_cur_l->slen) &&
+ (0 == temp_b.slen) )
+ {
+ sb_printf2 (R_cur_r, "(%.*s%.*s)*", 3, R_last_ik, &temp_a);
+ sb_free (R_cur_l);
+ R_cur_l->null_flag = GNUNET_YES;
+ }
+ else
+ {
+ sb_printf3 (R_cur_r, "(%.*s%.*s)+%.*s", 3, R_last_ik, &temp_a, &temp_b);
+ }
+ sb_free (&temp_a);
+ sb_free (&temp_b);
+ }
+ else if (0 == sb_strcmp (&R_temp_ik, &R_temp_kk) &&
+ 0 == sb_strcmp (&R_temp_kk, &R_temp_kj))
+ {
+ /*
+ * (e|a)a*(e|a) = a*
+ * (e|a)(e|a)*(e|a) = a*
+ */
+ if (has_epsilon (R_last_ik) && has_epsilon (R_last_kj))
+ {
+ if (needs_parentheses (&R_temp_kk))
+ sb_printf1 (R_cur_r, "(%.*s)*", 3, &R_temp_kk);
+ else
+ sb_printf1 (R_cur_r, "%.*s*", 1, &R_temp_kk);
+ }
+ /* aa*a = a+a */
+ else if ( (0 == clean_ik_kk_cmp) &&
+ (0 == clean_kk_kj_cmp) &&
+ (! has_epsilon (R_last_ik)) )
+ {
+ if (needs_parentheses (&R_temp_kk))
+ sb_printf2 (R_cur_r, "(%.*s)+%.*s", 3, &R_temp_kk, &R_temp_kk);
+ else
+ sb_printf2 (R_cur_r, "%.*s+%.*s", 1, &R_temp_kk, &R_temp_kk);
+ }
+ /*
+ * (e|a)a*a = a+
+ * aa*(e|a) = a+
+ * a(e|a)*(e|a) = a+
+ * (e|a)a*a = a+
+ */
+ else
+ {
+ eps_check =
+ (has_epsilon (R_last_ik) + has_epsilon (R_last_kk) +
+ has_epsilon (R_last_kj));
+
+ if (1 == eps_check)
+ {
+ if (needs_parentheses (&R_temp_kk))
+ sb_printf1 (R_cur_r, "(%.*s)+", 3, &R_temp_kk);
+ else
+ sb_printf1 (R_cur_r, "%.*s+", 1, &R_temp_kk);
+ }
+ }
+ }
+ /*
+ * aa*b = a+b
+ * (e|a)(e|a)*b = a*b
+ */
+ else if (0 == sb_strcmp (&R_temp_ik, &R_temp_kk))
+ {
+ if (has_epsilon (R_last_ik))
+ {
+ if (needs_parentheses (&R_temp_kk))
+ sb_printf2 (R_cur_r, "(%.*s)*%.*s", 3, &R_temp_kk, R_last_kj);
+ else
+ sb_printf2 (R_cur_r, "%.*s*%.*s", 1, &R_temp_kk, R_last_kj);
+ }
+ else
+ {
+ if (needs_parentheses (&R_temp_kk))
+ sb_printf2 (R_cur_r, "(%.*s)+%.*s", 3, &R_temp_kk, R_last_kj);
+ else
+ sb_printf2 (R_cur_r, "%.*s+%.*s", 1, &R_temp_kk, R_last_kj);
+ }
+ }
+ /*
+ * ba*a = ba+
+ * b(e|a)*(e|a) = ba*
+ */
+ else if (0 == sb_strcmp (&R_temp_kk, &R_temp_kj))
+ {
+ if (has_epsilon (R_last_kj))
+ {
+ if (needs_parentheses (&R_temp_kk))
+ sb_printf2 (R_cur_r, "%.*s(%.*s)*", 3, R_last_ik, &R_temp_kk);
+ else
+ sb_printf2 (R_cur_r, "%.*s%.*s*", 1, R_last_ik, &R_temp_kk);
+ }
+ else
+ {
+ if (needs_parentheses (&R_temp_kk))
+ sb_printf2 (R_cur_r, "(%.*s)+%.*s", 3, R_last_ik, &R_temp_kk);
+ else
+ sb_printf2 (R_cur_r, "%.*s+%.*s", 1, R_last_ik, &R_temp_kk);
+ }
+ }
+ else
+ {
+ if (0 < R_temp_kk.slen)
+ {
+ if (needs_parentheses (&R_temp_kk))
+ {
+ sb_printf3 (R_cur_r, "%.*s(%.*s)*%.*s", 3, R_last_ik, &R_temp_kk,
+ R_last_kj);
+ }
+ else
+ {
+ sb_printf3 (R_cur_r, "%.*s%.*s*%.*s", 1, R_last_ik, &R_temp_kk,
+ R_last_kj);
+ }
+ }
+ else
+ {
+ sb_printf2 (R_cur_r, "%.*s%.*s", 0, R_last_ik, R_last_kj);
+ }
+ }
+ }
+ sb_free (&R_temp_ij);
+ sb_free (&R_temp_ik);
+ sb_free (&R_temp_kk);
+ sb_free (&R_temp_kj);
+
+ if ( (GNUNET_YES == R_cur_l->null_flag) &&
+ (GNUNET_YES == R_cur_r->null_flag) )
+ {
+ R_cur_ij->null_flag = GNUNET_YES;
+ return;
+ }
+
+ if ( (GNUNET_YES != R_cur_l->null_flag) &&
+ (GNUNET_YES == R_cur_r->null_flag) )
+ {
+ struct StringBuffer tmp;
+
+ tmp = *R_cur_ij;
+ *R_cur_ij = *R_cur_l;
+ *R_cur_l = tmp;
+ return;
+ }
+
+ if ( (GNUNET_YES == R_cur_l->null_flag) &&
+ (GNUNET_YES != R_cur_r->null_flag) )
+ {
+ struct StringBuffer tmp;
+
+ tmp = *R_cur_ij;
+ *R_cur_ij = *R_cur_r;
+ *R_cur_r = tmp;
+ return;
+ }
+
+ if (0 == sb_nullstrcmp (R_cur_l, R_cur_r))
+ {
+ struct StringBuffer tmp;
+
+ tmp = *R_cur_ij;
+ *R_cur_ij = *R_cur_l;
+ *R_cur_l = tmp;
+ return;
+ }
+ sb_printf2 (R_cur_ij, "(%.*s|%.*s)", 3, R_cur_l, R_cur_r);
+}
+
+
+/**
+ * Create proofs for all states in the given automaton. Implementation of the
+ * algorithm descriped in chapter 3.2.1 of "Automata Theory, Languages, and
+ * Computation 3rd Edition" by Hopcroft, Motwani and Ullman.
+ *
+ * Each state in the automaton gets assigned 'proof' and 'hash' (hash of the
+ * proof) fields. The starting state will only have a valid proof/hash if it has
+ * any incoming transitions.
+ *
+ * @param a automaton for which to assign proofs and hashes, must not be NULL
+ */
+static int
+automaton_create_proofs (struct GNUNET_REGEX_Automaton *a)
+{
+ unsigned int n = a->state_count;
+ struct GNUNET_REGEX_State *states[n];
+ struct StringBuffer *R_last;
+ struct StringBuffer *R_cur;
+ struct StringBuffer R_cur_r;
+ struct StringBuffer R_cur_l;
+ struct StringBuffer *R_swap;
+ struct GNUNET_REGEX_Transition *t;
+ struct StringBuffer complete_regex;
+ unsigned int i;
+ unsigned int j;
+ unsigned int k;
+
+ R_last = GNUNET_malloc_large (sizeof (struct StringBuffer) * n * n);
+ R_cur = GNUNET_malloc_large (sizeof (struct StringBuffer) * n * n);
+ if ( (NULL == R_last) ||
+ (NULL == R_cur) )
+ {
+ GNUNET_log_strerror (GNUNET_ERROR_TYPE_ERROR, "malloc");
+ GNUNET_free_non_null (R_cur);
+ GNUNET_free_non_null (R_last);
+ return GNUNET_SYSERR;
+ }
+
+ /* create depth-first numbering of the states, initializes 'state' */
+ GNUNET_REGEX_automaton_traverse (a, a->start, NULL, NULL, &number_states,
+ states);
+
+ for (i = 0; i < n; i++)
+ GNUNET_assert (NULL != states[i]);
+ for (i = 0; i < n; i++)
+ for (j = 0; j < n; j++)
+ R_last[i *n + j].null_flag = GNUNET_YES;
+
+ /* Compute regular expressions of length "1" between each pair of states */
+ for (i = 0; i < n; i++)
+ {
+ for (t = states[i]->transitions_head; NULL != t; t = t->next)
+ {
+ j = t->to_state->dfs_id;
+ if (GNUNET_YES == R_last[i * n + j].null_flag)
+ {
+ sb_strdup_cstr (&R_last[i * n + j], t->label);
+ }
+ else
+ {
+ sb_append_cstr (&R_last[i * n + j], "|");
+ sb_append_cstr (&R_last[i * n + j], t->label);
+ }
+ }
+ /* add self-loop: i is reachable from i via epsilon-transition */
+ if (GNUNET_YES == R_last[i * n + i].null_flag)
+ {
+ R_last[i * n + i].slen = 0;
+ R_last[i * n + i].null_flag = GNUNET_NO;
+ }
+ else
+ {
+ sb_wrap (&R_last[i * n + i], "(|%.*s)", 3);
+ }
+ }
+ for (i = 0; i < n; i++)
+ for (j = 0; j < n; j++)
+ if (needs_parentheses (&R_last[i * n + j]))
+ sb_wrap (&R_last[i * n + j], "(%.*s)", 2);
+ /* Compute regular expressions of length "k" between each pair of states per
+ * induction */
+ memset (&R_cur_l, 0, sizeof (struct StringBuffer));
+ memset (&R_cur_r, 0, sizeof (struct StringBuffer));
+ for (k = 0; k < n; k++)
+ {
+ for (i = 0; i < n; i++)
+ {
+ for (j = 0; j < n; j++)
+ {
+ /* Basis for the recursion:
+ * $R^{(k)}_{ij} = R^{(k-1)}_{ij} | R^{(k-1)}_{ik} ( R^{(k-1)}_{kk} )^* R^{(k-1)}_{kj}
+ * R_last == R^{(k-1)}, R_cur == R^{(k)}
+ */
+
+ /* Create R_cur[i][j] and simplify the expression */
+ automaton_create_proofs_simplify (&R_last[i * n + j], &R_last[i * n + k],
+ &R_last[k * n + k], &R_last[k * n + j],
+ &R_cur[i * n + j],
+ &R_cur_l, &R_cur_r);
+ }
+ }
+ /* set R_last = R_cur */
+ R_swap = R_last;
+ R_last = R_cur;
+ R_cur = R_swap;
+ /* clear 'R_cur' for next iteration */
+ for (i = 0; i < n; i++)
+ for (j = 0; j < n; j++)
+ R_cur[i * n + j].null_flag = GNUNET_YES;
+ }
+ sb_free (&R_cur_l);
+ sb_free (&R_cur_r);
+ /* assign proofs and hashes */
+ for (i = 0; i < n; i++)
+ {
+ if (GNUNET_YES != R_last[a->start->dfs_id * n + i].null_flag)
+ {
+ states[i]->proof = GNUNET_strndup (R_last[a->start->dfs_id * n + i].sbuf,
+ R_last[a->start->dfs_id * n + i].slen);
+ GNUNET_CRYPTO_hash (states[i]->proof, strlen (states[i]->proof),
+ &states[i]->hash);
+ }
+ }
+
+ /* complete regex for whole DFA: union of all pairs (start state/accepting
+ * state(s)). */
+ sb_init (&complete_regex, 16 * n);
+ for (i = 0; i < n; i++)
+ {
+ if (states[i]->accepting)
+ {
+ if ( (0 == complete_regex.slen) &&
+ (0 < R_last[a->start->dfs_id * n + i].slen) )
+ {
+ sb_append (&complete_regex,
+ &R_last[a->start->dfs_id * n + i]);
+ }
+ else if ( (GNUNET_YES != R_last[a->start->dfs_id * n + i].null_flag) &&
+ (0 < R_last[a->start->dfs_id * n + i].slen) )
+ {
+ sb_append_cstr (&complete_regex, "|");
+ sb_append (&complete_regex,
+ &R_last[a->start->dfs_id * n + i]);
+ }
+ }
+ }
+ a->canonical_regex = GNUNET_strndup (complete_regex.sbuf, complete_regex.slen);
+
+ /* cleanup */
+ sb_free (&complete_regex);
+ for (i = 0; i < n; i++)
+ for (j = 0; j < n; j++)
+ {
+ sb_free (&R_cur[i * n + j]);
+ sb_free (&R_last[i * n + j]);
+ }
+ GNUNET_free (R_cur);
+ GNUNET_free (R_last);
+ return GNUNET_OK;
+}
+
+
/**
* Creates a new DFA state based on a set of NFA states. Needs to be freed using
* automaton_destroy_state.
struct GNUNET_REGEX_StateSet *nfa_states)
{
struct GNUNET_REGEX_State *s;
- char *name;
- int len = 0;
+ char *pos;
+ size_t len;
struct GNUNET_REGEX_State *cstate;
- struct Transition *ctran;
- int insert = 1;
- struct Transition *t;
- int i;
+ struct GNUNET_REGEX_Transition *ctran;
+ unsigned int i;
s = GNUNET_malloc (sizeof (struct GNUNET_REGEX_State));
s->id = ctx->state_id++;
- s->accepting = 0;
- s->marked = 0;
- s->name = NULL;
- s->scc_id = 0;
s->index = -1;
s->lowlink = -1;
- s->contained = 0;
if (NULL == nfa_states)
{
return s;
}
- s->nfa_set = nfa_states;
+ s->nfa_set = *nfa_states;
- if (nfa_states->len < 1)
+ if (nfa_states->off < 1)
return s;
- // Create a name based on 'sset'
- s->name = GNUNET_malloc (sizeof (char) * 2);
- strcat (s->name, "{");
- name = NULL;
-
- for (i = 0; i < nfa_states->len; i++)
- {
- cstate = nfa_states->states[i];
- GNUNET_asprintf (&name, "%i,", cstate->id);
-
- if (NULL != name)
- {
- len = strlen (s->name) + strlen (name) + 1;
- s->name = GNUNET_realloc (s->name, len);
- strcat (s->name, name);
- GNUNET_free (name);
- name = NULL;
- }
-
- // Add a transition for each distinct label to NULL state
- for (ctran = cstate->transitions_head; NULL != ctran; ctran = ctran->next)
- {
- if (0 != ctran->label)
- {
- insert = 1;
+ /* Create a name based on 'nfa_states' */
+ len = nfa_states->off * 14 + 4;
+ s->name = GNUNET_malloc (len);
+ strcat (s->name, "{");
+ pos = s->name + 1;
- for (t = s->transitions_head; NULL != t; t = t->next)
- {
- if (t->label == ctran->label)
- {
- insert = 0;
- break;
- }
- }
+ for (i = 0; i < nfa_states->off; i++)
+ {
+ cstate = nfa_states->states[i];
+ GNUNET_snprintf (pos, pos - s->name + len,
+ "%i,", cstate->id);
+ pos += strlen (pos);
- if (insert)
- state_add_transition (ctx, s, ctran->label, NULL);
- }
- }
+ /* Add a transition for each distinct label to NULL state */
+ for (ctran = cstate->transitions_head; NULL != ctran; ctran = ctran->next)
+ if (NULL != ctran->label)
+ state_add_transition (ctx, s, ctran->label, NULL);
- // If the nfa_states contain an accepting state, the new dfa state is also
- // accepting
+ /* If the nfa_states contain an accepting state, the new dfa state is also
+ * accepting. */
if (cstate->accepting)
s->accepting = 1;
- }
-
- s->name[strlen (s->name) - 1] = '}';
+ }
+ pos[-1] = '}';
+ s->name = GNUNET_realloc (s->name, strlen (s->name) + 1);
+ memset (nfa_states, 0, sizeof (struct GNUNET_REGEX_StateSet));
return s;
}
+
/**
- * Move from the given state 's' to the next state on transition 'label'
+ * Move from the given state 's' to the next state on transition 'str'. Consumes
+ * as much of the given 'str' as possible (usefull for strided DFAs). On return
+ * 's' will point to the next state, and the length of the substring used for
+ * this transition will be returned. If no transition possible 0 is returned and
+ * 's' points to NULL.
*
- * @param s starting state
- * @param label edge label to follow
+ * @param s starting state, will point to the next state or NULL (if no
+ * transition possible)
+ * @param str edge label to follow (will match longest common prefix)
*
- * @return new state or NULL, if transition on label not possible
+ * @return length of the substring comsumed from 'str'
*/
-static struct GNUNET_REGEX_State *
-dfa_move (struct GNUNET_REGEX_State *s, const char label)
+static unsigned int
+dfa_move (struct GNUNET_REGEX_State **s, const char *str)
{
- struct Transition *t;
+ struct GNUNET_REGEX_Transition *t;
struct GNUNET_REGEX_State *new_s;
+ unsigned int len;
+ unsigned int max_len;
if (NULL == s)
- return NULL;
+ return 0;
new_s = NULL;
-
- for (t = s->transitions_head; NULL != t; t = t->next)
+ max_len = 0;
+ for (t = (*s)->transitions_head; NULL != t; t = t->next)
{
- if (label == t->label)
+ len = strlen (t->label);
+
+ if (0 == strncmp (t->label, str, len))
{
- new_s = t->to_state;
- break;
+ if (len >= max_len)
+ {
+ max_len = len;
+ new_s = t->to_state;
+ }
}
}
- return new_s;
+ *s = new_s;
+ return max_len;
+}
+
+
+/**
+ * Set the given state 'marked' to GNUNET_YES. Used by the
+ * 'dfa_remove_unreachable_states' function to detect unreachable states in the
+ * automaton.
+ *
+ * @param cls closure, not used.
+ * @param count count, not used.
+ * @param s state where the marked attribute will be set to GNUNET_YES.
+ */
+static void
+mark_states (void *cls, const unsigned int count, struct GNUNET_REGEX_State *s)
+{
+ s->marked = GNUNET_YES;
}
struct GNUNET_REGEX_State *s;
struct GNUNET_REGEX_State *s_next;
- // 1. unmark all states
+ /* 1. unmark all states */
for (s = a->states_head; NULL != s; s = s->next)
s->marked = GNUNET_NO;
- // 2. traverse dfa from start state and mark all visited states
- automaton_traverse (NULL, a, NULL);
+ /* 2. traverse dfa from start state and mark all visited states */
+ GNUNET_REGEX_automaton_traverse (a, a->start, NULL, NULL, &mark_states, NULL);
- // 3. delete all states that were not visited
+ /* 3. delete all states that were not visited */
for (s = a->states_head; NULL != s; s = s_next)
{
s_next = s->next;
if (GNUNET_NO == s->marked)
- {
- GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Removed state %s\n", s->name);
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.
+ * not transition to any other state but themselves.
*
* @param a DFA automaton
*/
dfa_remove_dead_states (struct GNUNET_REGEX_Automaton *a)
{
struct GNUNET_REGEX_State *s;
- struct Transition *t;
+ struct GNUNET_REGEX_State *s_next;
+ struct GNUNET_REGEX_Transition *t;
int dead;
GNUNET_assert (DFA == a->type);
- for (s = a->states_head; NULL != s; s = s->next)
+ for (s = a->states_head; NULL != s; s = s_next)
{
+ s_next = s->next;
+
if (s->accepting)
continue;
if (0 == dead)
continue;
- // state s is dead, remove it
+ /* 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
+ * @return GNUNET_OK on success
*/
-static void
+static int
dfa_merge_nondistinguishable_states (struct GNUNET_REGEX_Context *ctx,
struct GNUNET_REGEX_Automaton *a)
{
- int i;
- int table[a->state_count][a->state_count];
+ uint32_t *table;
struct GNUNET_REGEX_State *s1;
struct GNUNET_REGEX_State *s2;
- struct Transition *t1;
- struct Transition *t2;
+ struct GNUNET_REGEX_Transition *t1;
+ struct GNUNET_REGEX_Transition *t2;
+ struct GNUNET_REGEX_State *s1_next;
+ struct GNUNET_REGEX_State *s2_next;
int change;
- int common_labels;
+ unsigned int num_equal_edges;
+ unsigned int i;
+ unsigned int state_cnt;
+ unsigned long long idx;
+ unsigned long long idx1;
- for (i = 0, s1 = a->states_head; i < a->state_count && NULL != s1;
- i++, s1 = s1->next)
+ if ( (NULL == a) || (0 == a->state_count) )
{
- s1->marked = i;
+ GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
+ "Could not merge nondistinguishable states, automaton was NULL.\n");
+ return GNUNET_SYSERR;
}
- // Mark all pairs of accepting/!accepting states
- for (s1 = a->states_head; NULL != s1; s1 = s1->next)
+ state_cnt = a->state_count;
+ table = GNUNET_malloc_large ((sizeof (uint32_t) * state_cnt * state_cnt / 32) + sizeof (uint32_t));
+ if (NULL == table)
{
- for (s2 = a->states_head; NULL != s2 && s1 != s2; s2 = s2->next)
- {
- if ((s1->accepting && !s2->accepting) ||
- (!s1->accepting && s2->accepting))
+ GNUNET_log_strerror (GNUNET_ERROR_TYPE_ERROR, "malloc");
+ return GNUNET_SYSERR;
+ }
+
+ for (i = 0, s1 = a->states_head; NULL != s1; 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; s2 = s2->next)
+ if ( (s1->accepting && !s2->accepting) ||
+ (!s1->accepting && s2->accepting) )
{
- table[s1->marked][s2->marked] = 1;
+ idx = s1->marked * state_cnt + s2->marked;
+ table[idx / 32] |= (1 << (idx % 32));
}
- else
- table[s1->marked][s2->marked] = 0;
- }
- }
+ /* Find all equal states */
change = 1;
while (0 != change)
{
{
for (s2 = a->states_head; NULL != s2 && s1 != s2; s2 = s2->next)
{
- if (0 != table[s1->marked][s2->marked])
+ idx = s1->marked * state_cnt + s2->marked;
+ if (0 != (table[idx / 32] & (1 << (idx % 32))))
continue;
-
- common_labels = GNUNET_NO;
+ num_equal_edges = 0;
for (t1 = s1->transitions_head; NULL != t1; t1 = t1->next)
{
for (t2 = s2->transitions_head; NULL != t2; t2 = t2->next)
{
- if (t1->label == t2->label)
- {
- common_labels = GNUNET_YES;
-
- if (0 != table[t1->to_state->marked][t2->to_state->marked] ||
- 0 != table[t2->to_state->marked][t1->to_state->marked])
- {
- table[s1->marked][s2->marked] = t1->label != 0 ? t1->label : 1;
- change = 1;
- }
- }
- }
+ if (0 == strcmp (t1->label, t2->label))
+ {
+ num_equal_edges++;
+ /* same edge, but targets definitively different, so we're different
+ as well */
+ if (t1->to_state->marked > t2->to_state->marked)
+ idx1 = t1->to_state->marked * state_cnt + t2->to_state->marked;
+ else
+ idx1 = t2->to_state->marked * state_cnt + t1->to_state->marked;
+ if (0 != (table[idx1 / 32] & (1 << (idx1 % 32))))
+ {
+ table[idx / 32] |= (1 << (idx % 32));
+ change = 1; /* changed a marker, need to run again */
+ }
+ }
+ }
+ }
+ if ( (num_equal_edges != s1->transition_count) ||
+ (num_equal_edges != s2->transition_count) )
+ {
+ /* Make sure ALL edges of possible equal states are the same */
+ table[idx / 32] |= (1 << (idx % 32));
+ change = 1; /* changed a marker, need to run again */
}
- if (GNUNET_NO == common_labels)
- table[s1->marked][s2->marked] = -2;
}
}
}
- struct GNUNET_REGEX_State *s2_next;
-
- for (s1 = a->states_head; NULL != s1; s1 = s1->next)
+ /* Merge states that are equal */
+ for (s1 = a->states_head; NULL != s1; s1 = s1_next)
{
+ s1_next = s1->next;
for (s2 = a->states_head; NULL != s2 && s1 != s2; s2 = s2_next)
{
s2_next = s2->next;
- if (table[s1->marked][s2->marked] == 0)
+ idx = s1->marked * state_cnt + s2->marked;
+ if (0 == (table[idx / 32] & (1 << (idx % 32))))
automaton_merge_states (ctx, a, s1, s2);
}
}
+
+ GNUNET_free (table);
+ return GNUNET_OK;
}
+
/**
* 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
+ * @return GNUNET_OK on success
*/
-static void
+static int
dfa_minimize (struct GNUNET_REGEX_Context *ctx,
struct GNUNET_REGEX_Automaton *a)
{
if (NULL == a)
- return;
+ return GNUNET_SYSERR;
GNUNET_assert (DFA == a->type);
- // 1. remove unreachable states
+ /* 1. remove unreachable states */
dfa_remove_unreachable_states (a);
- // 2. remove dead states
+ /* 2. remove dead states */
dfa_remove_dead_states (a);
- // 3. Merge nondistinguishable states
- dfa_merge_nondistinguishable_states (ctx, a);
+ /* 3. Merge nondistinguishable states */
+ if (GNUNET_OK != dfa_merge_nondistinguishable_states (ctx, a))
+ return GNUNET_SYSERR;
+ return GNUNET_OK;
+}
+
+
+/**
+ * Context for adding strided transitions to a DFA.
+ */
+struct GNUNET_REGEX_Strided_Context
+{
+ /**
+ * Length of the strides.
+ */
+ const unsigned int stride;
+
+ /**
+ * Strided transitions DLL. New strided transitions will be stored in this DLL
+ * and afterwards added to the DFA.
+ */
+ struct GNUNET_REGEX_Transition *transitions_head;
+
+ /**
+ * Strided transitions DLL.
+ */
+ struct GNUNET_REGEX_Transition *transitions_tail;
+};
+
+
+/**
+ * Recursive helper function to add strides to a DFA.
+ *
+ * @param cls context, contains stride length and strided transitions DLL.
+ * @param depth current depth of the depth-first traversal of the graph.
+ * @param label current label, string that contains all labels on the path from
+ * 'start' to 's'.
+ * @param start start state for the depth-first traversal of the graph.
+ * @param s current state in the depth-first traversal
+ */
+void
+dfa_add_multi_strides_helper (void *cls, const unsigned int depth, char *label,
+ struct GNUNET_REGEX_State *start,
+ struct GNUNET_REGEX_State *s)
+{
+ struct GNUNET_REGEX_Strided_Context *ctx = cls;
+ struct GNUNET_REGEX_Transition *t;
+ char *new_label;
+
+ if (depth == ctx->stride)
+ {
+ t = GNUNET_malloc (sizeof (struct GNUNET_REGEX_Transition));
+ t->label = GNUNET_strdup (label);
+ t->to_state = s;
+ t->from_state = start;
+ GNUNET_CONTAINER_DLL_insert (ctx->transitions_head, ctx->transitions_tail,
+ t);
+ }
+ else
+ {
+ for (t = s->transitions_head; NULL != t; t = t->next)
+ {
+ /* Do not consider self-loops, because it end's up in too many
+ * transitions */
+ if (t->to_state == t->from_state)
+ continue;
+
+ if (NULL != label)
+ {
+ GNUNET_asprintf (&new_label, "%s%s", label, t->label);
+ }
+ else
+ new_label = GNUNET_strdup (t->label);
+
+ dfa_add_multi_strides_helper (cls, (depth + 1), new_label, start,
+ t->to_state);
+ }
+ }
+ GNUNET_free_non_null (label);
+}
+
+
+/**
+ * Function called for each state in the DFA. Starts a traversal of depth set in
+ * context starting from state 's'.
+ *
+ * @param cls context.
+ * @param count not used.
+ * @param s current state.
+ */
+void
+dfa_add_multi_strides (void *cls, const unsigned int count,
+ struct GNUNET_REGEX_State *s)
+{
+ dfa_add_multi_strides_helper (cls, 0, NULL, s, s);
+}
+
+
+/**
+ * Adds multi-strided transitions to the given 'dfa'.
+ *
+ * @param regex_ctx regex context needed to add transitions to the automaton.
+ * @param dfa DFA to which the multi strided transitions should be added.
+ * @param stride_len length of the strides.
+ */
+void
+GNUNET_REGEX_dfa_add_multi_strides (struct GNUNET_REGEX_Context *regex_ctx,
+ struct GNUNET_REGEX_Automaton *dfa,
+ const unsigned int stride_len)
+{
+ struct GNUNET_REGEX_Strided_Context ctx = { stride_len, NULL, NULL };
+ struct GNUNET_REGEX_Transition *t;
+ struct GNUNET_REGEX_Transition *t_next;
+
+ if (1 > stride_len || GNUNET_YES == dfa->is_multistrided)
+ return;
+
+ /* Compute the new transitions of given stride_len */
+ GNUNET_REGEX_automaton_traverse (dfa, dfa->start, NULL, NULL,
+ &dfa_add_multi_strides, &ctx);
+
+ /* Add all the new transitions to the automaton. */
+ for (t = ctx.transitions_head; NULL != t; t = t_next)
+ {
+ t_next = t->next;
+ state_add_transition (regex_ctx, t->from_state, t->label, t->to_state);
+ GNUNET_CONTAINER_DLL_remove (ctx.transitions_head, ctx.transitions_tail, t);
+ GNUNET_free_non_null (t->label);
+ GNUNET_free (t);
+ }
+
+ /* Mark this automaton as multistrided */
+ dfa->is_multistrided = GNUNET_YES;
}
+/**
+ * Recursive Helper function for DFA path compression. Does DFS on the DFA graph
+ * and adds new transitions to the given transitions DLL and marks states that
+ * should be removed by setting state->contained to GNUNET_YES.
+ *
+ * @param dfa DFA for which the paths should be compressed.
+ * @param start starting state for linear path search.
+ * @param cur current state in the recursive DFS.
+ * @param label current label (string of traversed labels).
+ * @param max_len maximal path compression length.
+ * @param transitions_head transitions DLL.
+ * @param transitions_tail transitions DLL.
+ */
+void
+dfa_compress_paths_helper (struct GNUNET_REGEX_Automaton *dfa,
+ struct GNUNET_REGEX_State *start,
+ struct GNUNET_REGEX_State *cur, char *label,
+ unsigned int max_len,
+ struct GNUNET_REGEX_Transition **transitions_head,
+ struct GNUNET_REGEX_Transition **transitions_tail)
+{
+ struct GNUNET_REGEX_Transition *t;
+ char *new_label;
+
+
+ if (NULL != label &&
+ ((cur->incoming_transition_count > 1 || GNUNET_YES == cur->accepting ||
+ GNUNET_YES == cur->marked) || (start != dfa->start && max_len > 0 &&
+ max_len == strlen (label)) ||
+ (start == dfa->start && GNUNET_REGEX_INITIAL_BYTES == strlen (label))))
+ {
+ t = GNUNET_malloc (sizeof (struct GNUNET_REGEX_Transition));
+ t->label = GNUNET_strdup (label);
+ t->to_state = cur;
+ t->from_state = start;
+ GNUNET_CONTAINER_DLL_insert (*transitions_head, *transitions_tail, t);
+
+ if (GNUNET_NO == cur->marked)
+ {
+ dfa_compress_paths_helper (dfa, cur, cur, NULL, max_len, transitions_head,
+ transitions_tail);
+ }
+ return;
+ }
+ else if (cur != start)
+ cur->contained = GNUNET_YES;
+
+ if (GNUNET_YES == cur->marked && cur != start)
+ return;
+
+ cur->marked = GNUNET_YES;
+
+
+ for (t = cur->transitions_head; NULL != t; t = t->next)
+ {
+ if (NULL != label)
+ GNUNET_asprintf (&new_label, "%s%s", label, t->label);
+ else
+ new_label = GNUNET_strdup (t->label);
+
+ if (t->to_state != cur)
+ {
+ dfa_compress_paths_helper (dfa, start, t->to_state, new_label, max_len,
+ transitions_head, transitions_tail);
+ }
+ GNUNET_free (new_label);
+ }
+}
+
+
+/**
+ * Compress paths in the given 'dfa'. Linear paths like 0->1->2->3 will be
+ * compressed to 0->3 by combining transitions.
+ *
+ * @param regex_ctx context for adding new transitions.
+ * @param dfa DFA representation, will directly modify the given DFA.
+ * @param max_len maximal length of the compressed paths.
+ */
+static void
+dfa_compress_paths (struct GNUNET_REGEX_Context *regex_ctx,
+ struct GNUNET_REGEX_Automaton *dfa, unsigned int max_len)
+{
+ struct GNUNET_REGEX_State *s;
+ struct GNUNET_REGEX_State *s_next;
+ struct GNUNET_REGEX_Transition *t;
+ struct GNUNET_REGEX_Transition *t_next;
+ struct GNUNET_REGEX_Transition *transitions_head = NULL;
+ struct GNUNET_REGEX_Transition *transitions_tail = NULL;
+
+ if (NULL == dfa)
+ return;
+
+ /* Count the incoming transitions on each state. */
+ for (s = dfa->states_head; NULL != s; s = s->next)
+ {
+ for (t = s->transitions_head; NULL != t; t = t->next)
+ {
+ if (NULL != t->to_state)
+ t->to_state->incoming_transition_count++;
+ }
+ }
+
+ /* Unmark all states. */
+ for (s = dfa->states_head; NULL != s; s = s->next)
+ {
+ s->marked = GNUNET_NO;
+ s->contained = GNUNET_NO;
+ }
+
+ /* Add strides and mark states that can be deleted. */
+ dfa_compress_paths_helper (dfa, dfa->start, dfa->start, NULL, max_len,
+ &transitions_head, &transitions_tail);
+
+ /* Add all the new transitions to the automaton. */
+ for (t = transitions_head; NULL != t; t = t_next)
+ {
+ t_next = t->next;
+ state_add_transition (regex_ctx, t->from_state, t->label, t->to_state);
+ GNUNET_CONTAINER_DLL_remove (transitions_head, transitions_tail, t);
+ GNUNET_free_non_null (t->label);
+ GNUNET_free (t);
+ }
+
+ /* Remove marked states (including their incoming and outgoing transitions). */
+ for (s = dfa->states_head; NULL != s; s = s_next)
+ {
+ s_next = s->next;
+ if (GNUNET_YES == s->contained)
+ automaton_remove_state (dfa, s);
+ }
+}
+
+
/**
* Creates a new NFA fragment. Needs to be cleared using
* automaton_fragment_clear.
n->type = NFA;
n->start = NULL;
n->end = NULL;
+ n->state_count = 0;
- if (NULL == start && NULL == end)
+ if (NULL == start || NULL == end)
return n;
automaton_add_state (n, end);
automaton_add_state (n, start);
+ n->state_count = 2;
+
n->start = start;
n->end = end;
return n;
}
+
/**
* Adds a list of states to the given automaton 'n'.
*
n->state_count++;
}
+
/**
* Creates a new NFA state. Needs to be freed using automaton_destroy_state.
*
s = GNUNET_malloc (sizeof (struct GNUNET_REGEX_State));
s->id = ctx->state_id++;
s->accepting = accepting;
- s->marked = 0;
+ s->marked = GNUNET_NO;
s->contained = 0;
s->index = -1;
s->lowlink = -1;
return s;
}
-/**
- * Calculates the NFA closure set for the given state.
- *
- * @param nfa the NFA containing 's'
- * @param s starting point state
- * @param label transitioning label on which to base the closure on,
- * pass 0 for epsilon transition
- *
- * @return sorted nfa closure on 'label' (epsilon closure if 'label' is 0)
- */
-static struct GNUNET_REGEX_StateSet *
-nfa_closure_create (struct GNUNET_REGEX_Automaton *nfa,
- struct GNUNET_REGEX_State *s, const char label)
-{
- struct GNUNET_REGEX_StateSet *cls;
- struct GNUNET_REGEX_StateSet *cls_check;
- struct GNUNET_REGEX_State *clsstate;
- struct GNUNET_REGEX_State *currentstate;
- struct Transition *ctran;
-
- if (NULL == s)
- return NULL;
-
- cls = GNUNET_malloc (sizeof (struct GNUNET_REGEX_StateSet));
- cls_check = GNUNET_malloc (sizeof (struct GNUNET_REGEX_StateSet));
-
- for (clsstate = nfa->states_head; NULL != clsstate; clsstate = clsstate->next)
- clsstate->contained = 0;
-
- // Add start state to closure only for epsilon closure
- if (0 == label)
- 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->to_state && label == ctran->label)
- {
- clsstate = ctran->to_state;
-
- if (NULL != clsstate && 0 == clsstate->contained)
- {
- GNUNET_array_append (cls->states, cls->len, clsstate);
- GNUNET_array_append (cls_check->states, cls_check->len, clsstate);
- clsstate->contained = 1;
- }
- }
- }
- }
- GNUNET_assert (0 == cls_check->len);
- GNUNET_free (cls_check);
-
- if (cls->len > 1)
- qsort (cls->states, cls->len, sizeof (struct GNUNET_REGEX_State *),
- state_compare);
-
- return cls;
-}
/**
* Calculates the closure set for the given set of states.
*
+ * @param ret set to sorted nfa closure on 'label' (epsilon closure if 'label' is NULL)
* @param nfa the NFA containing 's'
* @param states list of states on which to base the closure on
* @param label transitioning label for which to base the closure on,
- * pass 0 for epsilon transition
- *
- * @return sorted nfa closure on 'label' (epsilon closure if 'label' is 0)
+ * pass NULL for epsilon transition
*/
-static struct GNUNET_REGEX_StateSet *
-nfa_closure_set_create (struct GNUNET_REGEX_Automaton *nfa,
- struct GNUNET_REGEX_StateSet *states, const char label)
+static void
+nfa_closure_set_create (struct GNUNET_REGEX_StateSet *ret,
+ struct GNUNET_REGEX_Automaton *nfa,
+ struct GNUNET_REGEX_StateSet *states, const char *label)
{
struct GNUNET_REGEX_State *s;
- struct GNUNET_REGEX_StateSet *sset;
- struct GNUNET_REGEX_StateSet *cls;
- int i;
- int j;
- int k;
- int contains;
+ unsigned int i;
+ struct GNUNET_REGEX_StateSet_MDLL cls_stack;
+ struct GNUNET_REGEX_State *clsstate;
+ struct GNUNET_REGEX_State *currentstate;
+ struct GNUNET_REGEX_Transition *ctran;
+ memset (ret, 0, sizeof (struct GNUNET_REGEX_StateSet));
if (NULL == states)
- return NULL;
-
- cls = GNUNET_malloc (sizeof (struct GNUNET_REGEX_StateSet));
+ return;
- for (i = 0; i < states->len; i++)
+ for (i = 0; i < states->off; i++)
{
s = states->states[i];
- sset = nfa_closure_create (nfa, s, label);
- for (j = 0; j < sset->len; j++)
+ /* Add start state to closure only for epsilon closure */
+ if (NULL == label)
+ state_set_append (ret, s);
+
+ /* initialize work stack */
+ cls_stack.head = NULL;
+ cls_stack.tail = NULL;
+ GNUNET_CONTAINER_MDLL_insert (ST, cls_stack.head, cls_stack.tail, s);
+ cls_stack.len = 1;
+
+ while (NULL != (currentstate = cls_stack.tail))
{
- contains = 0;
- for (k = 0; k < cls->len; k++)
+ GNUNET_CONTAINER_MDLL_remove (ST, cls_stack.head, cls_stack.tail,
+ currentstate);
+ cls_stack.len--;
+ for (ctran = currentstate->transitions_head; NULL != ctran;
+ ctran = ctran->next)
{
- if (sset->states[j]->id == cls->states[k]->id)
- {
- contains = 1;
- break;
- }
- }
- if (!contains)
- GNUNET_array_append (cls->states, cls->len, sset->states[j]);
+ if (NULL == (clsstate = ctran->to_state))
+ continue;
+ if (0 != clsstate->contained)
+ continue;
+ if (0 != nullstrcmp (label, ctran->label))
+ continue;
+ state_set_append (ret, clsstate);
+ GNUNET_CONTAINER_MDLL_insert_tail (ST, cls_stack.head, cls_stack.tail,
+ clsstate);
+ cls_stack.len++;
+ clsstate->contained = 1;
+ }
}
- state_set_clear (sset);
}
+ for (i = 0; i < ret->off; i++)
+ ret->states[i]->contained = 0;
- if (cls->len > 1)
- qsort (cls->states, cls->len, sizeof (struct GNUNET_REGEX_State *),
- state_compare);
-
- return cls;
+ if (ret->off > 1)
+ qsort (ret->states, ret->off, sizeof (struct GNUNET_REGEX_State *),
+ &state_compare);
}
+
/**
* Pops two NFA fragments (a, b) from the stack and concatenates them (ab)
*
{
struct GNUNET_REGEX_Automaton *a;
struct GNUNET_REGEX_Automaton *b;
- struct GNUNET_REGEX_Automaton *new;
+ struct GNUNET_REGEX_Automaton *new_nfa;
b = ctx->stack_tail;
+ GNUNET_assert (NULL != b);
GNUNET_CONTAINER_DLL_remove (ctx->stack_head, ctx->stack_tail, b);
a = ctx->stack_tail;
+ GNUNET_assert (NULL != a);
GNUNET_CONTAINER_DLL_remove (ctx->stack_head, ctx->stack_tail, a);
- state_add_transition (ctx, a->end, 0, b->start);
+ state_add_transition (ctx, a->end, NULL, b->start);
a->end->accepting = 0;
b->end->accepting = 1;
- 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;
+ new_nfa = nfa_fragment_create (NULL, NULL);
+ nfa_add_states (new_nfa, a->states_head, a->states_tail);
+ nfa_add_states (new_nfa, b->states_head, b->states_tail);
+ new_nfa->start = a->start;
+ new_nfa->end = b->end;
+ new_nfa->state_count += a->state_count + b->state_count;
automaton_fragment_clear (a);
automaton_fragment_clear (b);
- GNUNET_CONTAINER_DLL_insert_tail (ctx->stack_head, ctx->stack_tail, new);
+ GNUNET_CONTAINER_DLL_insert_tail (ctx->stack_head, ctx->stack_tail, new_nfa);
}
+
/**
* Pops a NFA fragment from the stack (a) and adds a new fragment (a*)
*
nfa_add_star_op (struct GNUNET_REGEX_Context *ctx)
{
struct GNUNET_REGEX_Automaton *a;
- struct GNUNET_REGEX_Automaton *new;
+ struct GNUNET_REGEX_Automaton *new_nfa;
struct GNUNET_REGEX_State *start;
struct GNUNET_REGEX_State *end;
a = ctx->stack_tail;
- GNUNET_CONTAINER_DLL_remove (ctx->stack_head, ctx->stack_tail, a);
if (NULL == a)
{
return;
}
+ GNUNET_CONTAINER_DLL_remove (ctx->stack_head, ctx->stack_tail, a);
+
start = nfa_state_create (ctx, 0);
end = nfa_state_create (ctx, 1);
- state_add_transition (ctx, start, 0, a->start);
- state_add_transition (ctx, start, 0, end);
- state_add_transition (ctx, a->end, 0, a->start);
- state_add_transition (ctx, a->end, 0, end);
+ state_add_transition (ctx, start, NULL, a->start);
+ state_add_transition (ctx, start, NULL, end);
+ state_add_transition (ctx, a->end, NULL, a->start);
+ state_add_transition (ctx, a->end, NULL, end);
a->end->accepting = 0;
end->accepting = 1;
- new = nfa_fragment_create (start, end);
- nfa_add_states (new, a->states_head, a->states_tail);
+ new_nfa = nfa_fragment_create (start, end);
+ nfa_add_states (new_nfa, a->states_head, a->states_tail);
automaton_fragment_clear (a);
- GNUNET_CONTAINER_DLL_insert_tail (ctx->stack_head, ctx->stack_tail, new);
+ GNUNET_CONTAINER_DLL_insert_tail (ctx->stack_head, ctx->stack_tail, new_nfa);
}
+
/**
* Pops an NFA fragment (a) from the stack and adds a new fragment (a+)
*
struct GNUNET_REGEX_Automaton *a;
a = ctx->stack_tail;
+
+ if (NULL == a)
+ {
+ GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
+ "nfa_add_plus_op failed, because there was no element on the stack");
+ return;
+ }
+
GNUNET_CONTAINER_DLL_remove (ctx->stack_head, ctx->stack_tail, a);
- state_add_transition (ctx, a->end, 0, a->start);
+ state_add_transition (ctx, a->end, NULL, a->start);
GNUNET_CONTAINER_DLL_insert_tail (ctx->stack_head, ctx->stack_tail, a);
}
+
/**
* Pops an NFA fragment (a) from the stack and adds a new fragment (a?)
*
nfa_add_question_op (struct GNUNET_REGEX_Context *ctx)
{
struct GNUNET_REGEX_Automaton *a;
- struct GNUNET_REGEX_Automaton *new;
+ struct GNUNET_REGEX_Automaton *new_nfa;
struct GNUNET_REGEX_State *start;
struct GNUNET_REGEX_State *end;
a = ctx->stack_tail;
- GNUNET_CONTAINER_DLL_remove (ctx->stack_head, ctx->stack_tail, a);
if (NULL == a)
{
return;
}
+ GNUNET_CONTAINER_DLL_remove (ctx->stack_head, ctx->stack_tail, a);
+
start = nfa_state_create (ctx, 0);
end = nfa_state_create (ctx, 1);
- state_add_transition (ctx, start, 0, a->start);
- state_add_transition (ctx, start, 0, end);
- state_add_transition (ctx, a->end, 0, end);
+ state_add_transition (ctx, start, NULL, a->start);
+ state_add_transition (ctx, start, NULL, end);
+ state_add_transition (ctx, a->end, NULL, end);
a->end->accepting = 0;
- new = nfa_fragment_create (start, end);
- nfa_add_states (new, a->states_head, a->states_tail);
+ new_nfa = nfa_fragment_create (start, end);
+ nfa_add_states (new_nfa, a->states_head, a->states_tail);
+ GNUNET_CONTAINER_DLL_insert_tail (ctx->stack_head, ctx->stack_tail, new_nfa);
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)
{
struct GNUNET_REGEX_Automaton *a;
struct GNUNET_REGEX_Automaton *b;
- struct GNUNET_REGEX_Automaton *new;
+ struct GNUNET_REGEX_Automaton *new_nfa;
struct GNUNET_REGEX_State *start;
struct GNUNET_REGEX_State *end;
b = ctx->stack_tail;
+ GNUNET_assert (NULL != b);
GNUNET_CONTAINER_DLL_remove (ctx->stack_head, ctx->stack_tail, b);
a = ctx->stack_tail;
+ GNUNET_assert (NULL != a);
GNUNET_CONTAINER_DLL_remove (ctx->stack_head, ctx->stack_tail, a);
start = nfa_state_create (ctx, 0);
end = nfa_state_create (ctx, 1);
- state_add_transition (ctx, start, 0, a->start);
- state_add_transition (ctx, start, 0, b->start);
+ state_add_transition (ctx, start, NULL, a->start);
+ state_add_transition (ctx, start, NULL, b->start);
- state_add_transition (ctx, a->end, 0, end);
- state_add_transition (ctx, b->end, 0, end);
+ state_add_transition (ctx, a->end, NULL, end);
+ state_add_transition (ctx, b->end, NULL, end);
a->end->accepting = 0;
b->end->accepting = 0;
end->accepting = 1;
- 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);
+ new_nfa = nfa_fragment_create (start, end);
+ nfa_add_states (new_nfa, a->states_head, a->states_tail);
+ nfa_add_states (new_nfa, b->states_head, b->states_tail);
automaton_fragment_clear (a);
automaton_fragment_clear (b);
- GNUNET_CONTAINER_DLL_insert_tail (ctx->stack_head, ctx->stack_tail, new);
+ GNUNET_CONTAINER_DLL_insert_tail (ctx->stack_head, ctx->stack_tail, new_nfa);
}
+
/**
* Adds a new nfa fragment to the stack
*
* @param ctx context
- * @param lit label for nfa transition
+ * @param label label for nfa transition
*/
static void
-nfa_add_label (struct GNUNET_REGEX_Context *ctx, const char lit)
+nfa_add_label (struct GNUNET_REGEX_Context *ctx, const char *label)
{
struct GNUNET_REGEX_Automaton *n;
struct GNUNET_REGEX_State *start;
start = nfa_state_create (ctx, 0);
end = nfa_state_create (ctx, 1);
- state_add_transition (ctx, start, lit, end);
+ state_add_transition (ctx, start, label, end);
n = nfa_fragment_create (start, end);
GNUNET_assert (NULL != n);
GNUNET_CONTAINER_DLL_insert_tail (ctx->stack_head, ctx->stack_tail, n);
}
+
/**
* Initialize a new context
*
}
ctx->state_id = 0;
ctx->transition_id = 0;
- ctx->scc_id = 0;
ctx->stack_head = NULL;
ctx->stack_tail = NULL;
}
+
/**
* Construct an NFA by parsing the regex string of length 'len'.
*
struct GNUNET_REGEX_Context ctx;
struct GNUNET_REGEX_Automaton *nfa;
const char *regexp;
+ char curlabel[2];
char *error_msg;
unsigned int count;
unsigned int altcount;
unsigned int atomcount;
- unsigned int pcount;
+ unsigned int poff;
+ unsigned int psize;
struct
{
int altcount;
int atomcount;
} *p;
+ if (NULL == regex || 0 == strlen (regex) || 0 == len)
+ {
+ GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
+ "Could not parse regex. Empty regex string provided.\n");
+
+ return NULL;
+ }
GNUNET_REGEX_context_init (&ctx);
regexp = regex;
+ curlabel[1] = '\0';
p = NULL;
error_msg = NULL;
altcount = 0;
atomcount = 0;
- pcount = 0;
+ poff = 0;
+ psize = 0;
for (count = 0; count < len && *regexp; count++, regexp++)
{
--atomcount;
nfa_add_concatenation (&ctx);
}
- GNUNET_array_grow (p, pcount, pcount + 1);
- p[pcount - 1].altcount = altcount;
- p[pcount - 1].atomcount = atomcount;
+ if (poff == psize)
+ GNUNET_array_grow (p, psize, psize * 2 + 4);
+ p[poff].altcount = altcount;
+ p[poff].atomcount = atomcount;
+ poff++;
altcount = 0;
atomcount = 0;
break;
altcount++;
break;
case ')':
- if (0 == pcount)
+ if (0 == poff)
{
error_msg = "Missing opening '('";
goto error;
}
if (0 == atomcount)
{
- // Ignore this: "()"
- pcount--;
- altcount = p[pcount].altcount;
- atomcount = p[pcount].atomcount;
+ /* Ignore this: "()" */
+ poff--;
+ altcount = p[poff].altcount;
+ atomcount = p[poff].atomcount;
break;
}
while (--atomcount > 0)
nfa_add_concatenation (&ctx);
for (; altcount > 0; altcount--)
nfa_add_alternation (&ctx);
- pcount--;
- altcount = p[pcount].altcount;
- atomcount = p[pcount].atomcount;
+ poff--;
+ altcount = p[poff].altcount;
+ atomcount = p[poff].atomcount;
atomcount++;
break;
case '*':
if (atomcount == 0)
{
- error_msg = "Cannot append '+' to nothing";
+ error_msg = "Cannot append '*' to nothing";
goto error;
}
nfa_add_star_op (&ctx);
}
nfa_add_question_op (&ctx);
break;
- case 92: /* escape: \ */
- regexp++;
- count++;
default:
if (atomcount > 1)
{
--atomcount;
nfa_add_concatenation (&ctx);
}
- nfa_add_label (&ctx, *regexp);
+ curlabel[0] = *regexp;
+ nfa_add_label (&ctx, curlabel);
atomcount++;
break;
}
}
- if (0 != pcount)
+ if (0 != poff)
{
error_msg = "Unbalanced parenthesis";
goto error;
for (; altcount > 0; altcount--)
nfa_add_alternation (&ctx);
- if (NULL != p)
- GNUNET_free (p);
+ GNUNET_array_grow (p, psize, 0);
nfa = ctx.stack_tail;
GNUNET_CONTAINER_DLL_remove (ctx.stack_head, ctx.stack_tail, nfa);
-
if (NULL != ctx.stack_head)
{
error_msg = "Creating the NFA failed. NFA stack was not empty!";
goto error;
}
+ /* Remember the regex that was used to generate this NFA */
+ nfa->regex = GNUNET_strdup (regex);
+
+ /* create depth-first numbering of the states for pretty printing */
+ GNUNET_REGEX_automaton_traverse (nfa, NULL, NULL, NULL, &number_states, NULL);
+
+ /* No multistriding added so far */
+ nfa->is_multistrided = GNUNET_NO;
+
return nfa;
error:
- GNUNET_log (GNUNET_ERROR_TYPE_ERROR, "Could not parse regex\n");
+ GNUNET_log (GNUNET_ERROR_TYPE_ERROR, "Could not parse regex: `%s'\n", regex);
if (NULL != error_msg)
GNUNET_log (GNUNET_ERROR_TYPE_ERROR, "%s\n", error_msg);
- if (NULL != p)
- GNUNET_free (p);
- while (NULL != ctx.stack_tail)
+
+ GNUNET_free_non_null (p);
+
+ while (NULL != (nfa = ctx.stack_head))
{
- GNUNET_REGEX_automaton_destroy (ctx.stack_tail);
- GNUNET_CONTAINER_DLL_remove (ctx.stack_head, ctx.stack_tail,
- ctx.stack_tail);
+ GNUNET_CONTAINER_DLL_remove (ctx.stack_head, ctx.stack_tail, nfa);
+ GNUNET_REGEX_automaton_destroy (nfa);
}
+
return NULL;
}
+
/**
* Create DFA states based on given 'nfa' and starting with 'dfa_state'.
*
struct GNUNET_REGEX_Automaton *dfa,
struct GNUNET_REGEX_State *dfa_state)
{
- struct Transition *ctran;
- struct GNUNET_REGEX_State *state_iter;
+ struct GNUNET_REGEX_Transition *ctran;
struct GNUNET_REGEX_State *new_dfa_state;
struct GNUNET_REGEX_State *state_contains;
- struct GNUNET_REGEX_StateSet *tmp;
- struct GNUNET_REGEX_StateSet *nfa_set;
+ struct GNUNET_REGEX_State *state_iter;
+ struct GNUNET_REGEX_StateSet tmp;
+ struct GNUNET_REGEX_StateSet nfa_set;
for (ctran = dfa_state->transitions_head; NULL != ctran; ctran = ctran->next)
{
- if (0 == ctran->label || NULL != ctran->to_state)
+ if (NULL == ctran->label || NULL != ctran->to_state)
continue;
- tmp = nfa_closure_set_create (nfa, dfa_state->nfa_set, ctran->label);
- nfa_set = nfa_closure_set_create (nfa, tmp, 0);
- state_set_clear (tmp);
- new_dfa_state = dfa_state_create (ctx, nfa_set);
+ nfa_closure_set_create (&tmp, nfa, &dfa_state->nfa_set, ctran->label);
+ nfa_closure_set_create (&nfa_set, nfa, &tmp, NULL);
+ state_set_clear (&tmp);
+
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))
+ if (0 == state_set_compare (&state_iter->nfa_set, &nfa_set))
+ {
state_contains = state_iter;
+ break;
+ }
}
-
if (NULL == state_contains)
{
+ new_dfa_state = dfa_state_create (ctx, &nfa_set);
automaton_add_state (dfa, new_dfa_state);
- construct_dfa_states (ctx, nfa, dfa, new_dfa_state);
ctran->to_state = new_dfa_state;
+ construct_dfa_states (ctx, nfa, dfa, new_dfa_state);
}
else
{
ctran->to_state = state_contains;
- automaton_destroy_state (new_dfa_state);
+ state_set_clear (&nfa_set);
}
}
}
+
/**
- * Construct DFA for the given 'regex' of length 'len'
+ * Construct DFA for the given 'regex' of length 'len'.
*
- * @param regex regular expression string
- * @param len length of the regular expression
+ * Path compression means, that for example a DFA o -> a -> b -> c -> o will be
+ * compressed to o -> abc -> o. Note that this parameter influences the
+ * non-determinism of states of the resulting NFA in the DHT (number of outgoing
+ * edges with the same label). For example for an application that stores IPv4
+ * addresses as bitstrings it could make sense to limit the path compression to
+ * 4 or 8.
*
- * @return DFA, needs to be freed using GNUNET_REGEX_destroy_automaton
+ * @param regex regular expression string.
+ * @param len length of the regular expression.
+ * @param max_path_len limit the path compression length to the
+ * given value. If set to 1, no path compression is applied. Set to 0 for
+ * maximal possible path compression (generally not desireable).
+ * @return DFA, needs to be freed using GNUNET_REGEX_automaton_destroy.
*/
struct GNUNET_REGEX_Automaton *
-GNUNET_REGEX_construct_dfa (const char *regex, const size_t len)
+GNUNET_REGEX_construct_dfa (const char *regex, const size_t len,
+ unsigned int max_path_len)
{
struct GNUNET_REGEX_Context ctx;
struct GNUNET_REGEX_Automaton *dfa;
struct GNUNET_REGEX_Automaton *nfa;
- struct GNUNET_REGEX_StateSet *nfa_set;
+ struct GNUNET_REGEX_StateSet nfa_start_eps_cls;
+ struct GNUNET_REGEX_StateSet singleton_set;
GNUNET_REGEX_context_init (&ctx);
- // Create NFA
+ /* Create NFA */
+ // fprintf (stderr, "N");
nfa = GNUNET_REGEX_construct_nfa (regex, len);
if (NULL == nfa)
dfa = GNUNET_malloc (sizeof (struct GNUNET_REGEX_Automaton));
dfa->type = DFA;
-
- // Create DFA start state from epsilon closure
- nfa_set = nfa_closure_create (nfa, nfa->start, 0);
- dfa->start = dfa_state_create (&ctx, nfa_set);
+ dfa->regex = GNUNET_strdup (regex);
+
+ /* Create DFA start state from epsilon closure */
+ memset (&singleton_set, 0, sizeof (struct GNUNET_REGEX_StateSet));
+ state_set_append (&singleton_set, nfa->start);
+ nfa_closure_set_create (&nfa_start_eps_cls, nfa, &singleton_set, NULL);
+ state_set_clear (&singleton_set);
+ dfa->start = dfa_state_create (&ctx, &nfa_start_eps_cls);
automaton_add_state (dfa, dfa->start);
+ // fprintf (stderr, "D");
construct_dfa_states (&ctx, nfa, dfa, dfa->start);
-
GNUNET_REGEX_automaton_destroy (nfa);
- dfa_minimize (&ctx, dfa);
- scc_tarjan (&ctx, dfa);
+ /* Minimize DFA */
+ // fprintf (stderr, "M");
+ if (GNUNET_OK != dfa_minimize (&ctx, dfa))
+ {
+ GNUNET_REGEX_automaton_destroy (dfa);
+ return NULL;
+ }
+
+ /* Create proofs and hashes for all states */
+ if (GNUNET_OK != automaton_create_proofs (dfa))
+ {
+ GNUNET_REGEX_automaton_destroy (dfa);
+ return NULL;
+ }
+
+ /* Compress linear DFA paths */
+ if (1 != max_path_len)
+ dfa_compress_paths (&ctx, dfa, max_path_len);
return dfa;
}
+
/**
* Free the memory allocated by constructing the GNUNET_REGEX_Automaton data
* structure.
if (NULL == a)
return;
- for (s = a->states_head; NULL != s;)
+ GNUNET_free_non_null (a->regex);
+ GNUNET_free_non_null (a->canonical_regex);
+
+ for (s = a->states_head; NULL != s; s = next_state)
{
next_state = s->next;
+ GNUNET_CONTAINER_DLL_remove (a->states_head, a->states_tail, s);
automaton_destroy_state (s);
- s = next_state;
}
GNUNET_free (a);
}
-/**
- * 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_automaton_save_graph (struct GNUNET_REGEX_Automaton *a,
- const char *filename)
-{
- struct GNUNET_REGEX_State *s;
- struct Transition *ctran;
- char *s_acc = NULL;
- char *s_tran = NULL;
- char *start;
- char *end;
- FILE *p;
-
- if (NULL == a)
- {
- GNUNET_log (GNUNET_ERROR_TYPE_ERROR, "Could not print NFA, was NULL!");
- return;
- }
-
- if (NULL == filename || strlen (filename) < 1)
- {
- GNUNET_log (GNUNET_ERROR_TYPE_ERROR, "No Filename given!");
- return;
- }
-
- p = fopen (filename, "w");
-
- if (NULL == p)
- {
- GNUNET_log (GNUNET_ERROR_TYPE_ERROR, "Could not open file for writing: %s",
- filename);
- return;
- }
-
- start = "digraph G {\nrankdir=LR\n";
- fwrite (start, strlen (start), 1, p);
-
- for (s = a->states_head; NULL != s; s = s->next)
- {
- if (s->accepting)
- {
- GNUNET_asprintf (&s_acc,
- "\"%s\" [shape=doublecircle, color=\"0.%i 0.8 0.95\"];\n",
- s->name, s->scc_id);
- }
- else
- {
- GNUNET_asprintf (&s_acc, "\"%s\" [color=\"0.%i 0.8 0.95\"];\n", s->name,
- s->scc_id);
- }
-
- if (NULL == s_acc)
- {
- GNUNET_log (GNUNET_ERROR_TYPE_ERROR, "Could not print state %s\n",
- s->name);
- return;
- }
- fwrite (s_acc, strlen (s_acc), 1, p);
- GNUNET_free (s_acc);
- s_acc = NULL;
-
- for (ctran = s->transitions_head; NULL != ctran; ctran = ctran->next)
- {
- if (NULL == ctran->to_state)
- {
- GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
- "Transition from State %i has has no state for transitioning\n",
- s->id);
- continue;
- }
-
- if (ctran->label == 0)
- {
- GNUNET_asprintf (&s_tran,
- "\"%s\" -> \"%s\" [label = \"epsilon\", color=\"0.%i 0.8 0.95\"];\n",
- s->name, ctran->to_state->name, s->scc_id);
- }
- else
- {
- GNUNET_asprintf (&s_tran,
- "\"%s\" -> \"%s\" [label = \"%c\", color=\"0.%i 0.8 0.95\"];\n",
- s->name, ctran->to_state->name, ctran->label,
- s->scc_id);
- }
-
- if (NULL == s_tran)
- {
- GNUNET_log (GNUNET_ERROR_TYPE_ERROR, "Could not print state %s\n",
- s->name);
- return;
- }
-
- fwrite (s_tran, strlen (s_tran), 1, p);
- GNUNET_free (s_tran);
- s_tran = NULL;
- }
- }
-
- end = "\n}\n";
- fwrite (end, strlen (end), 1, p);
- fclose (p);
-}
/**
* Evaluates the given string using the given DFA automaton
{
const char *strp;
struct GNUNET_REGEX_State *s;
+ unsigned int step_len;
if (DFA != a->type)
{
s = a->start;
- for (strp = string; NULL != strp && *strp; strp++)
+ /* If the string is empty but the starting state is accepting, we accept. */
+ if ((NULL == string || 0 == strlen (string)) && s->accepting)
+ return 0;
+
+ for (strp = string; NULL != strp && *strp; strp += step_len)
{
- s = dfa_move (s, *strp);
+ step_len = dfa_move (&s, strp);
+
if (NULL == s)
break;
}
return 1;
}
+
/**
* Evaluates the given string using the given NFA automaton
*
evaluate_nfa (struct GNUNET_REGEX_Automaton *a, const char *string)
{
const char *strp;
+ char str[2];
struct GNUNET_REGEX_State *s;
- struct GNUNET_REGEX_StateSet *sset;
- struct GNUNET_REGEX_StateSet *new_sset;
- int i;
+ struct GNUNET_REGEX_StateSet sset;
+ struct GNUNET_REGEX_StateSet new_sset;
+ struct GNUNET_REGEX_StateSet singleton_set;
+ unsigned int i;
int result;
if (NFA != a->type)
return -1;
}
+ /* If the string is empty but the starting state is accepting, we accept. */
+ if ((NULL == string || 0 == strlen (string)) && a->start->accepting)
+ return 0;
+
result = 1;
- strp = string;
- sset = nfa_closure_create (a, a->start, 0);
+ memset (&singleton_set, 0, sizeof (struct GNUNET_REGEX_StateSet));
+ state_set_append (&singleton_set, a->start);
+ nfa_closure_set_create (&sset, a, &singleton_set, NULL);
+ state_set_clear (&singleton_set);
+ str[1] = '\0';
for (strp = string; NULL != strp && *strp; strp++)
{
- new_sset = nfa_closure_set_create (a, sset, *strp);
- state_set_clear (sset);
- sset = nfa_closure_set_create (a, new_sset, 0);
- state_set_clear (new_sset);
+ str[0] = *strp;
+ nfa_closure_set_create (&new_sset, a, &sset, str);
+ state_set_clear (&sset);
+ nfa_closure_set_create (&sset, a, &new_sset, 0);
+ state_set_clear (&new_sset);
}
- for (i = 0; i < sset->len; i++)
+ for (i = 0; i < sset.off; i++)
{
- s = sset->states[i];
- if (NULL != s && s->accepting)
+ s = sset.states[i];
+ if ( (NULL != s) && (s->accepting) )
{
result = 0;
break;
}
}
- state_set_clear (sset);
+ state_set_clear (&sset);
return result;
}
+
/**
* Evaluates the given 'string' against the given compiled regex
*
return result;
}
+
+/**
+ * Get the canonical regex of the given automaton.
+ * When constructing the automaton a proof is computed for each state,
+ * consisting of the regular expression leading to this state. A complete
+ * regex for the automaton can be computed by combining these proofs.
+ * As of now this function is only useful for testing.
+ *
+ * @param a automaton for which the canonical regex should be returned.
+ *
+ * @return
+ */
+const char *
+GNUNET_REGEX_get_canonical_regex (struct GNUNET_REGEX_Automaton *a)
+{
+ if (NULL == a)
+ return NULL;
+
+ return a->canonical_regex;
+}
+
+
+/**
+ * Get the number of transitions that are contained in the given automaton.
+ *
+ * @param a automaton for which the number of transitions should be returned.
+ *
+ * @return number of transitions in the given automaton.
+ */
+unsigned int
+GNUNET_REGEX_get_transition_count (struct GNUNET_REGEX_Automaton *a)
+{
+ unsigned int t_count;
+ struct GNUNET_REGEX_State *s;
+
+ if (NULL == a)
+ return 0;
+
+ t_count = 0;
+ for (s = a->states_head; NULL != s; s = s->next)
+ t_count += s->transition_count;
+
+ return t_count;
+}
+
+
/**
* Get the first key for the given 'input_string'. This hashes the first x bits
- * of the 'input_strings'.
+ * of the 'input_string'.
*
* @param input_string string.
* @param string_len length of the 'input_string'.
* @return number of bits of 'input_string' that have been consumed
* to construct the key
*/
-unsigned int
-GNUNET_REGEX_get_first_key (const char *input_string, unsigned int string_len,
- GNUNET_HashCode * key)
+size_t
+GNUNET_REGEX_get_first_key (const char *input_string, size_t string_len,
+ struct GNUNET_HashCode * key)
{
unsigned int size;
- size = string_len < initial_bits ? string_len : initial_bits;
+ size =
+ string_len <
+ GNUNET_REGEX_INITIAL_BYTES ? string_len : GNUNET_REGEX_INITIAL_BYTES;
if (NULL == input_string)
{
return size;
}
+
/**
* Check if the given 'proof' matches the given 'key'.
*
- * @param proof partial regex
- * @param key hash
+ * @param proof partial regex of a state.
+ * @param key hash of a state.
*
- * @return GNUNET_OK if the proof is valid for the given key
+ * @return GNUNET_OK if the proof is valid for the given key.
*/
int
-GNUNET_REGEX_check_proof (const char *proof, const GNUNET_HashCode * key)
+GNUNET_REGEX_check_proof (const char *proof, const struct GNUNET_HashCode *key)
{
- return GNUNET_OK;
+ struct GNUNET_HashCode key_check;
+
+ if (NULL == proof || NULL == key)
+ {
+ GNUNET_log (GNUNET_ERROR_TYPE_ERROR, "Proof check failed, was NULL.\n");
+ return GNUNET_NO;
+ }
+
+ GNUNET_CRYPTO_hash (proof, strlen (proof), &key_check);
+ return (0 ==
+ GNUNET_CRYPTO_hash_cmp (key, &key_check)) ? GNUNET_OK : GNUNET_NO;
}
/**
- * Iterate over all edges helper function starting from state 's', calling
- * iterator on for each edge.
+ * Recursive function that calls the iterator for each synthetic start state.
*
- * @param s state.
+ * @param min_len minimum length of the path in the graph.
+ * @param max_len maximum length of the path in the graph.
+ * @param consumed_string string consumed by traversing the graph till this state.
+ * @param state current state of the automaton.
* @param iterator iterator function called for each edge.
- * @param iterator_cls closure.
+ * @param iterator_cls closure for the iterator function.
*/
static void
-iterate_edge (struct GNUNET_REGEX_State *s, GNUNET_REGEX_KeyIterator iterator,
- void *iterator_cls)
+iterate_initial_edge (const unsigned int min_len, const unsigned int max_len,
+ char *consumed_string, struct GNUNET_REGEX_State *state,
+ GNUNET_REGEX_KeyIterator iterator, void *iterator_cls)
{
- struct Transition *t;
- struct GNUNET_REGEX_Edge edges[s->transition_count];
- unsigned int num_edges;
-
- if (GNUNET_YES != s->marked)
+ unsigned int i;
+ char *temp;
+ struct GNUNET_REGEX_Transition *t;
+ unsigned int num_edges = state->transition_count;
+ struct GNUNET_REGEX_Edge edges[num_edges];
+ struct GNUNET_REGEX_Edge edge[1];
+ struct GNUNET_HashCode hash;
+ struct GNUNET_HashCode hash_new;
+
+ unsigned int cur_len;
+
+ if (NULL != consumed_string)
+ cur_len = strlen (consumed_string);
+ else
+ cur_len = 0;
+
+ if ((cur_len >= min_len || GNUNET_YES == state->accepting) && cur_len > 0 &&
+ NULL != consumed_string)
{
- s->marked = GNUNET_YES;
+ if (cur_len <= max_len)
+ {
+ if (state->proof != NULL && 0 != strcmp (consumed_string, state->proof))
+ {
+ for (i = 0, t = state->transitions_head; NULL != t && i < num_edges;
+ t = t->next, i++)
+ {
+ edges[i].label = t->label;
+ edges[i].destination = t->to_state->hash;
+ }
+ GNUNET_CRYPTO_hash (consumed_string, strlen (consumed_string), &hash);
+ iterator (iterator_cls, &hash, consumed_string, state->accepting,
+ num_edges, edges);
+ }
- num_edges = state_get_edges (s, edges);
+ if (GNUNET_YES == state->accepting && cur_len > 1 &&
+ state->transition_count < 1 && cur_len < max_len)
+ {
+ /* Special case for regex consisting of just a string that is shorter than
+ * max_len */
+ edge[0].label = &consumed_string[cur_len - 1];
+ edge[0].destination = state->hash;
+ temp = GNUNET_strdup (consumed_string);
+ temp[cur_len - 1] = '\0';
+ GNUNET_CRYPTO_hash (temp, cur_len - 1, &hash_new);
+ iterator (iterator_cls, &hash_new, temp, GNUNET_NO, 1, edge);
+ GNUNET_free (temp);
+ }
+ }
+ else if (max_len < cur_len)
+ {
+ /* Case where the concatenated labels are longer than max_len, then split. */
+ edge[0].label = &consumed_string[max_len];
+ edge[0].destination = state->hash;
+ temp = GNUNET_strdup (consumed_string);
+ temp[max_len] = '\0';
+ GNUNET_CRYPTO_hash (temp, max_len, &hash);
+ iterator (iterator_cls, &hash, temp, GNUNET_NO, 1, edge);
+ GNUNET_free (temp);
+ }
+ }
- iterator (iterator_cls, &s->hash, NULL, s->accepting, num_edges, edges);
+ if (cur_len < max_len)
+ {
+ for (t = state->transitions_head; NULL != t; t = t->next)
+ {
+ if (NULL != consumed_string)
+ GNUNET_asprintf (&temp, "%s%s", consumed_string, t->label);
+ else
+ GNUNET_asprintf (&temp, "%s", t->label);
- for (t = s->transitions_head; NULL != t; t = t->next)
- iterate_edge (t->to_state, iterator, iterator_cls);
+ iterate_initial_edge (min_len, max_len, temp, t->to_state, iterator,
+ iterator_cls);
+ GNUNET_free (temp);
+ }
}
}
+
/**
* Iterate over all edges starting from start state of automaton 'a'. Calling
* iterator for each edge.
struct GNUNET_REGEX_State *s;
for (s = a->states_head; NULL != s; s = s->next)
+ {
+ struct GNUNET_REGEX_Edge edges[s->transition_count];
+ unsigned int num_edges;
+
+ num_edges = state_get_edges (s, edges);
+
+ if ((NULL != s->proof && 0 < strlen (s->proof)) || s->accepting)
+ iterator (iterator_cls, &s->hash, s->proof, s->accepting, num_edges,
+ edges);
+
s->marked = GNUNET_NO;
+ }
+
+ iterate_initial_edge (GNUNET_REGEX_INITIAL_BYTES, GNUNET_REGEX_INITIAL_BYTES,
+ NULL, a->start, iterator, iterator_cls);
+}
+
+
+/**
+ * Create a string with binary IP notation for the given 'addr' in 'str'.
+ *
+ * @param af address family of the given 'addr'.
+ * @param addr address that should be converted to a string.
+ * struct in_addr * for IPv4 and struct in6_addr * for IPv6.
+ * @param str string that will contain binary notation of 'addr'. Expected
+ * to be at least 33 bytes long for IPv4 and 129 bytes long for IPv6.
+ */
+static void
+iptobinstr (const int af, const void *addr, char *str)
+{
+ int i;
+
+ switch (af)
+ {
+ case AF_INET:
+ {
+ uint32_t b = htonl (((struct in_addr *) addr)->s_addr);
+
+ str[32] = '\0';
+ str += 31;
+ for (i = 31; i >= 0; i--)
+ {
+ *str = (b & 1) + '0';
+ str--;
+ b >>= 1;
+ }
+ break;
+ }
+ case AF_INET6:
+ {
+ struct in6_addr b = *(const struct in6_addr *) addr;
+
+ str[128] = '\0';
+ str += 127;
+ for (i = 127; i >= 0; i--)
+ {
+ *str = (b.s6_addr[i / 8] & 1) + '0';
+ str--;
+ b.s6_addr[i / 8] >>= 1;
+ }
+ break;
+ }
+ }
+}
+
+
+/**
+ * Get the ipv4 network prefix from the given 'netmask'.
+ *
+ * @param netmask netmask for which to get the prefix len.
+ *
+ * @return length of ipv4 prefix for 'netmask'.
+ */
+static unsigned int
+ipv4netmasktoprefixlen (const char *netmask)
+{
+ struct in_addr a;
+ unsigned int len;
+ uint32_t t;
+
+ if (1 != inet_pton (AF_INET, netmask, &a))
+ return 0;
+ len = 32;
+ for (t = htonl (~a.s_addr); 0 != t; t >>= 1)
+ len--;
+ return len;
+}
+
+
+/**
+ * Create a regex in 'rxstr' from the given 'ip' and 'netmask'.
+ *
+ * @param ip IPv4 representation.
+ * @param netmask netmask for the ip.
+ * @param rxstr generated regex, must be at least GNUNET_REGEX_IPV4_REGEXLEN
+ * bytes long.
+ */
+void
+GNUNET_REGEX_ipv4toregex (const struct in_addr *ip, const char *netmask,
+ char *rxstr)
+{
+ unsigned int pfxlen;
+
+ pfxlen = ipv4netmasktoprefixlen (netmask);
+ iptobinstr (AF_INET, ip, rxstr);
+ rxstr[pfxlen] = '\0';
+ if (pfxlen < 32)
+ strcat (rxstr, "(0|1)+");
+}
+
+
+/**
+ * Create a regex in 'rxstr' from the given 'ipv6' and 'prefixlen'.
+ *
+ * @param ipv6 IPv6 representation.
+ * @param prefixlen length of the ipv6 prefix.
+ * @param rxstr generated regex, must be at least GNUNET_REGEX_IPV6_REGEXLEN
+ * bytes long.
+ */
+void
+GNUNET_REGEX_ipv6toregex (const struct in6_addr *ipv6, unsigned int prefixlen,
+ char *rxstr)
+{
+ iptobinstr (AF_INET6, ipv6, rxstr);
+ rxstr[prefixlen] = '\0';
+ if (prefixlen < 128)
+ strcat (rxstr, "(0|1)+");
+}
+
+
+struct RegexCombineCtx {
+ struct RegexCombineCtx *next;
+ struct RegexCombineCtx *prev;
+
+ struct RegexCombineCtx *head;
+ struct RegexCombineCtx *tail;
+
+ char *s;
+};
+
+
+static char *
+regex_combine (struct RegexCombineCtx *ctx)
+{
+ struct RegexCombineCtx *p;
+ size_t len;
+ char *regex;
+ char *tmp;
+ char *s;
+
+ if (NULL != ctx->s)
+ GNUNET_asprintf (®ex, "%s(", ctx->s);
+ else
+ regex = GNUNET_strdup ("(");
+ GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "prefix: %s\n", regex);
+
+ for (p = ctx->head; NULL != p; p = p->next)
+ {
+ s = regex_combine (p);
+ GNUNET_asprintf (&tmp, "%s%s|", regex, s);
+ GNUNET_free_non_null (s);
+ GNUNET_free_non_null (regex);
+ regex = tmp;
+ }
+ len = strlen (regex);
+ if (1 == len)
+ return GNUNET_strdup ("");
+
+ GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "pre-partial: %s\n", regex);
+ if ('|' == regex[len - 1])
+ regex[len - 1] = ')';
+ if ('(' == regex[len - 1])
+ regex[len - 1] = '\0';
+
+ GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "partial: %s\n", regex);
+ return regex;
+}
+
+static void
+regex_add (struct RegexCombineCtx *ctx, const char *regex)
+{
+ struct RegexCombineCtx *p;
+ const char *rest;
+
+ rest = ®ex[1];
+ for (p = ctx->head; NULL != p; p = p->next)
+ {
+ if (p->s[0] == regex[0])
+ {
+ if (1 == strlen(p->s))
+ {
+ GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "common char %s\n", p->s);
+ GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "adding %s\n", rest);
+ regex_add (p, rest);
+ }
+ else
+ {
+ struct RegexCombineCtx *new;
+ new = GNUNET_malloc (sizeof (struct RegexCombineCtx));
+ new->s = GNUNET_strdup (&p->s[1]);
+ GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, " p has now %s\n", p->s);
+ GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, " p will have %.1s\n", p->s);
+ GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, " regex is %s\n", regex);
+ GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, " new has now %s\n", new->s);
+ GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, " rest is now %s\n", rest);
+ p->s[1] = '\0'; /* dont realloc */
+ GNUNET_CONTAINER_DLL_insert (p->head, p->tail, new);
+ regex_add (p, rest);
+ }
+ return;
+ }
+ }
+ GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, " no match\n");
+ GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, " new state %s\n", regex);
+ GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, " under %s\n", ctx->s);
+ p = GNUNET_malloc (sizeof (struct RegexCombineCtx));
+ p->s = GNUNET_strdup (regex);
+ GNUNET_CONTAINER_DLL_insert (ctx->head, ctx->tail, p);
+}
+/*
+static void
+debug (struct RegexCombineCtx *ctx, int lvl)
+{
+ struct RegexCombineCtx *p;
+ unsigned int i;
+
+ for (i = 0; i < lvl; i++) fprintf (stderr, " ");
+ fprintf (stderr, "%s\n", ctx->s);
+
+ for (p = ctx->head; NULL != p; p = p->next)
+ {
+ debug (p, lvl + 2);
+ }
+}*/
- iterate_edge (a->start, iterator, iterator_cls);
+char *
+GNUNET_REGEX_combine (char * const regexes[])
+{
+ unsigned int i;
+ char *combined;
+ const char *current;
+ struct RegexCombineCtx ctx;
+
+ memset (&ctx, 0, sizeof (struct RegexCombineCtx));
+ for (i = 0; regexes[i]; i++)
+ {
+ current = regexes[i];
+ GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Regex %u: %s\n", i, current);
+ regex_add (&ctx, current);
+ }
+ GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "\nCombining...\n");
+
+ combined = regex_combine (&ctx);
+
+ return combined;
}
+
+/* end of regex.c */
projects / oweals / gnunet.git / blobdiff