diff options
Diffstat (limited to 'src/regex/regex.c')
| -rw-r--r-- | src/regex/regex.c | 3373 |
1 files changed, 2357 insertions, 1016 deletions
diff --git a/src/regex/regex.c b/src/regex/regex.c index 5244c26..ad8e56b 100644 --- a/src/regex/regex.c +++ b/src/regex/regex.c @@ -19,417 +19,80 @@ */ /** * @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). * @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; -}; +#include "regex_internal.h" /** - * Type of an automaton. + * Set this to GNUNET_YES to enable state naming. Used to debug NFA->DFA + * creation. Disabled by default for better performance. */ -enum GNUNET_REGEX_automaton_type -{ - NFA, - DFA -}; +#define REGEX_DEBUG_DFA GNUNET_NO /** - * Automaton representation. + * Set of states using MDLL API. */ -struct GNUNET_REGEX_Automaton +struct GNUNET_REGEX_StateSet_MDLL { /** - * 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. + * MDLL of states. */ - unsigned int state_count; + struct GNUNET_REGEX_State *head; /** - * DLL of states. + * MDLL of states. */ - struct GNUNET_REGEX_State *states_head; + struct GNUNET_REGEX_State *tail; /** - * DLL of states - */ - struct GNUNET_REGEX_State *states_tail; - - /** - * Type of the automaton. - */ - enum GNUNET_REGEX_automaton_type type; -}; - -/** - * A state. Can be used in DFA and NFA automatons. - */ -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; -}; - -/** - * Transition between two states. Each state can have 0-n transitions. If label - * is 0, this is considered to be an epsilon transition. - */ -struct Transition -{ - /** - * This is a linked list. - */ - struct Transition *prev; - - /** - * This is a linked list. - */ - struct Transition *next; - - /** - * Unique id of this transition. - */ - unsigned int id; - - /** - * Label for this transition. This is basically the edge label for the graph. - */ - char label; - - /** - * State to which this transition leads. - */ - struct GNUNET_REGEX_State *to_state; - - /** - * State from which this transition origins. - */ - struct GNUNET_REGEX_State *from_state; - - /** - * Mark this transition. For example when reversing the automaton. - */ - int mark; -}; - -/** - * Set of states. - */ -struct GNUNET_REGEX_StateSet -{ - /** - * Array of states. - */ - struct GNUNET_REGEX_State **states; - - /** - * Length of the 'states' array. + * Length of the MDLL. */ unsigned int len; }; -/* - * Debug helper functions - */ -void -debug_print_transitions (struct GNUNET_REGEX_State *); - -void -debug_print_state (struct GNUNET_REGEX_State *s) -{ - char *proof; - - if (NULL == s->proof) - proof = "NULL"; - else - proof = s->proof; - - GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, - "State %i: %s marked: %i accepting: %i scc_id: %i transitions: %i proof: %s\n", - s->id, s->name, s->marked, s->accepting, s->scc_id, - s->transition_count, proof); - - GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Transitions:\n"); - debug_print_transitions (s); -} - -void -debug_print_states (struct GNUNET_REGEX_Automaton *a) -{ - struct GNUNET_REGEX_State *s; - - for (s = a->states_head; NULL != s; s = s->next) - debug_print_state (s); -} - -void -debug_print_transition (struct Transition *t) -{ - char *to_state; - char *from_state; - char label; - - if (NULL == t) - return; - - if (0 == t->label) - label = '0'; - else - label = t->label; - - if (NULL == t->to_state) - to_state = "NULL"; - else - to_state = t->to_state->name; - - if (NULL == t->from_state) - from_state = "NULL"; - else - from_state = t->from_state->name; - - GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Transition %i: From %s on %c to %s\n", - t->id, from_state, label, to_state); -} - -void -debug_print_transitions (struct GNUNET_REGEX_State *s) -{ - struct Transition *t; - - for (t = s->transitions_head; NULL != t; t = t->next) - debug_print_transition (t); -} /** - * 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) { - 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 (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. @@ -441,11 +104,11 @@ scc_tarjan (struct GNUNET_REGEX_Context *ctx, struct GNUNET_REGEX_Automaton *a) */ 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) { @@ -453,33 +116,64 @@ state_add_transition (struct GNUNET_REGEX_Context *ctx, 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. * @@ -493,27 +187,26 @@ state_add_transition (struct GNUNET_REGEX_Context *ctx, 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) @@ -525,7 +218,7 @@ state_get_edges (struct GNUNET_REGEX_State *s, struct GNUNET_REGEX_Edge *edges) { if (NULL != t->to_state) { - edges[count].label = &t->label; + edges[count].label = t->label; edges[count].destination = t->to_state->hash; count++; } @@ -533,39 +226,37 @@ state_get_edges (struct GNUNET_REGEX_State *s, struct GNUNET_REGEX_Edge *edges) 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' * @@ -574,14 +265,11 @@ state_set_compare (struct GNUNET_REGEX_StateSet *sset1, 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. @@ -602,6 +290,7 @@ automaton_fragment_clear (struct GNUNET_REGEX_Automaton *a) GNUNET_free (a); } + /** * Frees the memory used by State 's' * @@ -610,30 +299,25 @@ automaton_fragment_clear (struct GNUNET_REGEX_Automaton *a) 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); - - if (NULL != s->proof) - GNUNET_free (s->proof); - + 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 @@ -646,39 +330,36 @@ static void 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 @@ -692,48 +373,61 @@ automaton_merge_states (struct GNUNET_REGEX_Context *ctx, struct GNUNET_REGEX_State *s2) { struct GNUNET_REGEX_State *s_check; - struct Transition *t_check; - char *new_name; - - GNUNET_assert (NULL != ctx && NULL != a && NULL != s1 && NULL != s2); + struct GNUNET_REGEX_Transition *t_check; + struct GNUNET_REGEX_Transition *t; + struct GNUNET_REGEX_Transition *t_next; + int is_dup; 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. @@ -749,154 +443,1316 @@ automaton_add_state (struct GNUNET_REGEX_Automaton *a, a->state_count++; } -/** - * Function that is called with each state, when traversing an automaton. - * - * @param cls closure - * @param s state - */ -typedef void (*GNUNET_REGEX_traverse_action) (void *cls, - struct GNUNET_REGEX_State * s); /** - * 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_YES == marks[s->traversal_id]) + return; - if (GNUNET_NO == s->marked) + marks[s->traversal_id] = GNUNET_YES; + + if (NULL != action) + action (action_cls, *count, s); + + (*count)++; + + for (t = s->transitions_head; NULL != t; t = t->next) { - s->marked = GNUNET_YES; + 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); + } + } +} - if (action > 0) - action (cls, s); - for (t = s->transitions_head; NULL != t; t = t->next) - automaton_state_traverse (cls, t->to_state, action); +/** + * 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 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 + */ +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; + + 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); } + /** - * Traverses the given automaton from it's start state, visiting all reachable - * states and calling 'action' on each one of them. + * 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 cls closure. - * @param a automaton. - * @param action action to be performed on each state. + * @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 -automaton_traverse (void *cls, struct GNUNET_REGEX_Automaton *a, - GNUNET_REGEX_traverse_action action) +sb_realloc (struct StringBuffer *ret, + size_t nlen) { - struct GNUNET_REGEX_State *s; + 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); +} + - for (s = a->states_head; NULL != s; s = s->next) - s->marked = GNUNET_NO; +/** + * 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; +} + - automaton_state_traverse (cls, a->start, action); +/** + * 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; } + /** - * Reverses all transitions of the given automaton. + * Format a string buffer. Note that optimizing this function is not + * really worth it, it is rarely called. * - * @param a automaton. + * @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 -automaton_reverse (struct GNUNET_REGEX_Automaton *a) +sb_printf1 (struct StringBuffer *ret, + const char *format, + size_t extra_chars, + const struct StringBuffer *sarg) { - struct GNUNET_REGEX_State *s; - struct Transition *t; - struct Transition *t_next; - struct GNUNET_REGEX_State *s_swp; + 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); +} - for (s = a->states_head; NULL != s; s = s->next) - for (t = s->transitions_head; NULL != t; t = t->next) - t->mark = GNUNET_NO; - for (s = a->states_head; NULL != s; s = s->next) +/** + * 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); +} + + +/** + * 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) { - for (t = s->transitions_head; NULL != t; t = t_next) + 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) { - t_next = t->next; + 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; +} - if (GNUNET_YES == t->mark || t->from_state == t->to_state) - continue; - t->mark = 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; +} - GNUNET_CONTAINER_DLL_remove (t->from_state->transitions_head, - t->from_state->transitions_tail, t); - t->from_state->transition_count--; - GNUNET_CONTAINER_DLL_insert (t->to_state->transitions_head, - t->to_state->transitions_tail, t); - t->to_state->transition_count++; - s_swp = t->from_state; - t->from_state = t->to_state; - t->to_state = s_swp; +/** + * 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); } + /** - * Create proof for the given state. + * Compare n bytes of 'str1' and 'str2' * - * @param cls closure. - * @param s state. + * @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 -automaton_create_proofs_step (void *cls, struct GNUNET_REGEX_State *s) +sb_init (struct StringBuffer *sb, + size_t n) { - struct Transition *t; - int i; - char *tmp; + 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) + - for (i = 0, t = s->transitions_head; NULL != t; t = t->next, i++) +/** + * 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))) { - if (t->to_state == s) - GNUNET_asprintf (&tmp, "%c*", t->label); - else if (i != s->transition_count - 1) - GNUNET_asprintf (&tmp, "%c|", t->label); + /* 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 - GNUNET_asprintf (&tmp, "%c", t->label); + { + 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 (NULL != s->proof) - s->proof = - GNUNET_realloc (s->proof, strlen (s->proof) + strlen (tmp) + 1); + 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 - s->proof = GNUNET_malloc (strlen (tmp) + 1); - strcat (s->proof, tmp); - GNUNET_free (tmp); + { + 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. + * 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. * - * @param a automaton. + * 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 void +static int automaton_create_proofs (struct GNUNET_REGEX_Automaton *a) { - struct GNUNET_REGEX_State *s; + 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; + } - automaton_reverse (a); + /* create depth-first numbering of the states, initializes 'state' */ + GNUNET_REGEX_automaton_traverse (a, a->start, NULL, NULL, &number_states, + states); - for (s = a->states_head; NULL != s; s = s->next) - automaton_create_proofs_step (NULL, s); + 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; - automaton_reverse (a); + /* 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. @@ -911,24 +1767,16 @@ dfa_state_create (struct GNUNET_REGEX_Context *ctx, 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; - s->proof = NULL; if (NULL == nfa_states) { @@ -936,93 +1784,103 @@ dfa_state_create (struct GNUNET_REGEX_Context *ctx, 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); + /* Create a name based on 'nfa_states' */ + len = nfa_states->off * 14 + 4; + s->name = GNUNET_malloc (len); strcat (s->name, "{"); - name = NULL; + pos = s->name + 1; - for (i = 0; i < nfa_states->len; i++) + for (i = 0; i < nfa_states->off; 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; - - for (t = s->transitions_head; NULL != t; t = t->next) - { - if (t->label == ctran->label) - { - insert = 0; - break; - } - } + 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; } + /** * Remove all unreachable states from DFA 'a'. Unreachable states are those * states that are not reachable from the starting state. @@ -1035,14 +1893,14 @@ dfa_remove_unreachable_states (struct GNUNET_REGEX_Automaton *a) 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; @@ -1051,9 +1909,10 @@ dfa_remove_unreachable_states (struct GNUNET_REGEX_Automaton *a) } } + /** * 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 */ @@ -1061,13 +1920,16 @@ static void 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; @@ -1084,54 +1946,66 @@ dfa_remove_dead_states (struct GNUNET_REGEX_Automaton *a) 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 num_equal_edges; + 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; s2 = s2->next) - { - table[s1->marked][s2->marked] = 0; + 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++; - if ((s1->accepting && !s2->accepting) || - (!s1->accepting && s2->accepting)) + /* 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)); } - } - } - // Find all equal states + /* Find all equal states */ change = 1; while (0 != change) { @@ -1140,75 +2014,351 @@ dfa_merge_nondistinguishable_states (struct GNUNET_REGEX_Context *ctx, { 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; - 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) - { - num_equal_edges++; - 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) + 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[s1->marked][s2->marked] = -2; + /* 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 */ } } } } - // Merge states that are equal + /* 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. @@ -1229,19 +2379,23 @@ nfa_fragment_create (struct GNUNET_REGEX_State *start, 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'. * @@ -1279,6 +2433,7 @@ nfa_add_states (struct GNUNET_REGEX_Automaton *n, n->state_count++; } + /** * Creates a new NFA state. Needs to be freed using automaton_destroy_state. * @@ -1295,7 +2450,7 @@ nfa_state_create (struct GNUNET_REGEX_Context *ctx, int accepting) 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; @@ -1306,127 +2461,77 @@ nfa_state_create (struct GNUNET_REGEX_Context *ctx, int accepting) 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) * @@ -1437,28 +2542,32 @@ nfa_add_concatenation (struct GNUNET_REGEX_Context *ctx) { 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*) * @@ -1468,12 +2577,11 @@ static void 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) { @@ -1482,24 +2590,27 @@ nfa_add_star_op (struct GNUNET_REGEX_Context *ctx) 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+) * @@ -1511,13 +2622,22 @@ nfa_add_plus_op (struct GNUNET_REGEX_Context *ctx) 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?) * @@ -1527,12 +2647,11 @@ static void 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) { @@ -1541,22 +2660,24 @@ nfa_add_question_op (struct GNUNET_REGEX_Context *ctx) 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) @@ -1568,44 +2689,47 @@ nfa_add_alternation (struct GNUNET_REGEX_Context *ctx) { 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; @@ -1615,12 +2739,13 @@ nfa_add_label (struct GNUNET_REGEX_Context *ctx, const char lit) 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 * @@ -1636,11 +2761,11 @@ GNUNET_REGEX_context_init (struct GNUNET_REGEX_Context *ctx) } 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'. * @@ -1655,25 +2780,36 @@ GNUNET_REGEX_construct_nfa (const char *regex, const size_t len) struct GNUNET_REGEX_Context ctx; struct GNUNET_REGEX_Automaton *nfa; const char *regexp; + char 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++) { @@ -1685,9 +2821,11 @@ GNUNET_REGEX_construct_nfa (const char *regex, const size_t len) --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; @@ -1702,26 +2840,26 @@ GNUNET_REGEX_construct_nfa (const char *regex, const size_t len) 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 '*': @@ -1748,21 +2886,19 @@ GNUNET_REGEX_construct_nfa (const char *regex, const size_t len) } 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; @@ -1772,8 +2908,7 @@ GNUNET_REGEX_construct_nfa (const char *regex, const size_t len) 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); @@ -1784,23 +2919,34 @@ GNUNET_REGEX_construct_nfa (const char *regex, const size_t len) 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'. * @@ -1816,32 +2962,35 @@ construct_dfa_states (struct GNUNET_REGEX_Context *ctx, 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); ctran->to_state = new_dfa_state; construct_dfa_states (ctx, nfa, dfa, new_dfa_state); @@ -1849,30 +2998,43 @@ construct_dfa_states (struct GNUNET_REGEX_Context *ctx, 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' - * - * @param regex regular expression string - * @param len length of the regular expression - * - * @return DFA, needs to be freed using GNUNET_REGEX_destroy_automaton + * Construct DFA for the given 'regex' of length 'len'. + * + * 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. + * + * @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) @@ -1884,28 +3046,43 @@ GNUNET_REGEX_construct_dfa (const char *regex, const size_t len) 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); - // Minimize DFA - dfa_minimize (&ctx, dfa); + /* Minimize DFA */ + // fprintf (stderr, "M"); + if (GNUNET_OK != dfa_minimize (&ctx, dfa)) + { + GNUNET_REGEX_automaton_destroy (dfa); + return NULL; + } - // Calculate SCCs - scc_tarjan (&ctx, dfa); + /* Create proofs and hashes for all states */ + if (GNUNET_OK != automaton_create_proofs (dfa)) + { + GNUNET_REGEX_automaton_destroy (dfa); + return NULL; + } - // Create proofs for all states - automaton_create_proofs (dfa); + /* 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. @@ -1921,123 +3098,19 @@ GNUNET_REGEX_automaton_destroy (struct GNUNET_REGEX_Automaton *a) 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 @@ -2052,6 +3125,7 @@ evaluate_dfa (struct GNUNET_REGEX_Automaton *a, const char *string) { const char *strp; struct GNUNET_REGEX_State *s; + unsigned int step_len; if (DFA != a->type) { @@ -2062,9 +3136,14 @@ evaluate_dfa (struct GNUNET_REGEX_Automaton *a, const char *string) 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; } @@ -2075,6 +3154,7 @@ evaluate_dfa (struct GNUNET_REGEX_Automaton *a, const char *string) return 1; } + /** * Evaluates the given string using the given NFA automaton * @@ -2087,10 +3167,12 @@ static int 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) @@ -2100,32 +3182,41 @@ evaluate_nfa (struct GNUNET_REGEX_Automaton *a, const char *string) 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 * @@ -2157,9 +3248,55 @@ GNUNET_REGEX_eval (struct GNUNET_REGEX_Automaton *a, const char *string) 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'. @@ -2168,13 +3305,15 @@ GNUNET_REGEX_eval (struct GNUNET_REGEX_Automaton *a, const char *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) { @@ -2187,49 +3326,125 @@ GNUNET_REGEX_get_first_key (const char *input_string, unsigned int string_len, 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; + 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 (GNUNET_YES != s->marked) + 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, s->proof, 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. @@ -2246,7 +3461,133 @@ GNUNET_REGEX_iterate_all_edges (struct GNUNET_REGEX_Automaton *a, 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; + } + } +} + - iterate_edge (a->start, iterator, iterator_cls); +/** + * 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)+"); +} + + +/* end of regex.c */ |