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- /*
- This file is part of GNUnet
- (C) 2012 Christian Grothoff (and other contributing authors)
- GNUnet is free software; you can redistribute it and/or modify
- it under the terms of the GNU General Public License as published
- by the Free Software Foundation; either version 3, or (at your
- option) any later version.
- GNUnet is distributed in the hope that it will be useful, but
- WITHOUT ANY WARRANTY; without even the implied warranty of
- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
- General Public License for more details.
- You should have received a copy of the GNU General Public License
- along with GNUnet; see the file COPYING. If not, write to the
- Free Software Foundation, Inc., 59 Temple Place - Suite 330,
- Boston, MA 02111-1307, USA.
- */
- /**
- * @file src/regex/regex_internal.c
- * @brief library to create Deterministic Finite Automatons (DFAs) from regular
- * expressions (regexes).
- * @author Maximilian Szengel
- */
- #include "platform.h"
- #include "gnunet_util_lib.h"
- #include "gnunet_regex_service.h"
- #include "regex_internal_lib.h"
- #include "regex_internal.h"
- /**
- * Set this to GNUNET_YES to enable state naming. Used to debug NFA->DFA
- * creation. Disabled by default for better performance.
- */
- #define REGEX_DEBUG_DFA GNUNET_NO
- /**
- * Set of states using MDLL API.
- */
- struct REGEX_INTERNAL_StateSet_MDLL
- {
- /**
- * MDLL of states.
- */
- struct REGEX_INTERNAL_State *head;
- /**
- * MDLL of states.
- */
- struct REGEX_INTERNAL_State *tail;
- /**
- * Length of the MDLL.
- */
- unsigned int len;
- };
- /**
- * Append state to the given StateSet '
- *
- * @param set set to be modified
- * @param state state to be appended
- */
- static void
- state_set_append (struct REGEX_INTERNAL_StateSet *set,
- struct REGEX_INTERNAL_State *state)
- {
- if (set->off == set->size)
- GNUNET_array_grow (set->states, set->size, set->size * 2 + 4);
- set->states[set->off++] = state;
- }
- /**
- * Compare two strings for equality. If either is NULL they are not equal.
- *
- * @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 int
- nullstrcmp (const char *str1, const char *str2)
- {
- if ((NULL == str1) != (NULL == str2))
- return -1;
- if ((NULL == str1) && (NULL == str2))
- return 0;
- return strcmp (str1, str2);
- }
- /**
- * Adds a transition from one state to another on 'label'. Does not add
- * duplicate states.
- *
- * @param ctx context
- * @param from_state starting state for the transition
- * @param label transition label
- * @param to_state state to where the transition should point to
- */
- static void
- state_add_transition (struct REGEX_INTERNAL_Context *ctx,
- struct REGEX_INTERNAL_State *from_state, const char *label,
- struct REGEX_INTERNAL_State *to_state)
- {
- struct REGEX_INTERNAL_Transition *t;
- struct REGEX_INTERNAL_Transition *oth;
- if (NULL == from_state)
- {
- GNUNET_log (GNUNET_ERROR_TYPE_ERROR, "Could not create Transition.\n");
- return;
- }
- /* Do not add duplicate state transitions */
- for (t = from_state->transitions_head; NULL != t; t = t->next)
- {
- if (t->to_state == to_state && 0 == nullstrcmp (t->label, label) &&
- t->from_state == from_state)
- 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_new (struct REGEX_INTERNAL_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' */
- from_state->transition_count++;
- 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 REGEX_INTERNAL_State *state,
- struct REGEX_INTERNAL_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.
- *
- * @param a first state
- * @param b second state
- *
- * @return an integer less than, equal to, or greater than zero
- * if the first argument is considered to be respectively
- * less than, equal to, or greater than the second.
- */
- static int
- state_compare (const void *a, const void *b)
- {
- struct REGEX_INTERNAL_State **s1 = (struct REGEX_INTERNAL_State **) a;
- struct REGEX_INTERNAL_State **s2 = (struct REGEX_INTERNAL_State **) b;
- return (*s1)->id - (*s2)->id;
- }
- /**
- * Get all edges leaving state 's'.
- *
- * @param s state.
- * @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 REGEX_INTERNAL_State *s, struct REGEX_BLOCK_Edge *edges)
- {
- struct REGEX_INTERNAL_Transition *t;
- unsigned int count;
- if (NULL == s)
- return 0;
- count = 0;
- for (t = s->transitions_head; NULL != t; t = t->next)
- {
- if (NULL != t->to_state)
- {
- edges[count].label = t->label;
- edges[count].destination = t->to_state->hash;
- count++;
- }
- }
- return count;
- }
- /**
- * Compare to state sets by comparing the id's of the states that are contained
- * in each set. Both sets are expected to be sorted by id!
- *
- * @param sset1 first state set
- * @param sset2 second state set
- * @return 0 if the sets are equal, otherwise non-zero
- */
- static int
- state_set_compare (struct REGEX_INTERNAL_StateSet *sset1,
- struct REGEX_INTERNAL_StateSet *sset2)
- {
- int result;
- unsigned int i;
- if (NULL == sset1 || NULL == sset2)
- return 1;
- 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;
- return result;
- }
- /**
- * Clears the given StateSet 'set'
- *
- * @param set set to be cleared
- */
- static void
- state_set_clear (struct REGEX_INTERNAL_StateSet *set)
- {
- GNUNET_array_grow (set->states, set->size, 0);
- set->off = 0;
- }
- /**
- * Clears an automaton fragment. Does not destroy the states inside the
- * automaton.
- *
- * @param a automaton to be cleared
- */
- static void
- automaton_fragment_clear (struct REGEX_INTERNAL_Automaton *a)
- {
- if (NULL == a)
- return;
- a->start = NULL;
- a->end = NULL;
- a->states_head = NULL;
- a->states_tail = NULL;
- a->state_count = 0;
- GNUNET_free (a);
- }
- /**
- * Frees the memory used by State 's'
- *
- * @param s state that should be destroyed
- */
- static void
- automaton_destroy_state (struct REGEX_INTERNAL_State *s)
- {
- struct REGEX_INTERNAL_Transition *t;
- struct REGEX_INTERNAL_Transition *next_t;
- if (NULL == s)
- return;
- 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;
- state_remove_transition (s, t);
- }
- 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
- * to this state, before destroying it.
- *
- * @param a automaton
- * @param s state to remove
- */
- static void
- automaton_remove_state (struct REGEX_INTERNAL_Automaton *a,
- struct REGEX_INTERNAL_State *s)
- {
- struct REGEX_INTERNAL_State *s_check;
- struct REGEX_INTERNAL_Transition *t_check;
- struct REGEX_INTERNAL_Transition *t_check_next;
- if (NULL == a || NULL == s)
- return;
- /* 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_next = t_check->next;
- if (t_check->to_state == s)
- state_remove_transition (s_check, t_check);
- }
- }
- /* 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'. 's1' will contain all (non-duplicate) outgoing transitions of 's2'.
- *
- * @param ctx context
- * @param a automaton
- * @param s1 first state
- * @param s2 second state, will be destroyed
- */
- static void
- automaton_merge_states (struct REGEX_INTERNAL_Context *ctx,
- struct REGEX_INTERNAL_Automaton *a,
- struct REGEX_INTERNAL_State *s1,
- struct REGEX_INTERNAL_State *s2)
- {
- struct REGEX_INTERNAL_State *s_check;
- struct REGEX_INTERNAL_Transition *t_check;
- struct REGEX_INTERNAL_Transition *t;
- struct REGEX_INTERNAL_Transition *t_next;
- int is_dup;
- if (s1 == s2)
- return;
- /* 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_next)
- {
- t_next = t_check->next;
- if (s2 == t_check->to_state)
- {
- 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 */
- 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} */
- #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 */
- 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.
- *
- * @param a automaton to add the state to
- * @param s state that should be added
- */
- static void
- automaton_add_state (struct REGEX_INTERNAL_Automaton *a,
- struct REGEX_INTERNAL_State *s)
- {
- GNUNET_CONTAINER_DLL_insert (a->states_head, a->states_tail, s);
- a->state_count++;
- }
- /**
- * Depth-first traversal (DFS) of all states that are reachable from state
- * 's'. Performs 'action' on each visited state.
- *
- * @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 (struct REGEX_INTERNAL_State *s, int *marks,
- unsigned int *count,
- REGEX_INTERNAL_traverse_check check, void *check_cls,
- REGEX_INTERNAL_traverse_action action, void *action_cls)
- {
- struct REGEX_INTERNAL_Transition *t;
- if (GNUNET_YES == marks[s->traversal_id])
- return;
- 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)
- {
- if (NULL == check ||
- (NULL != check && GNUNET_YES == check (check_cls, s, t)))
- {
- automaton_state_traverse (t->to_state, marks, count, check, check_cls,
- action, action_cls);
- }
- }
- }
- /**
- * Traverses the given automaton 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
- REGEX_INTERNAL_automaton_traverse (const struct REGEX_INTERNAL_Automaton *a,
- struct REGEX_INTERNAL_State *start,
- REGEX_INTERNAL_traverse_check check,
- void *check_cls,
- REGEX_INTERNAL_traverse_action action,
- void *action_cls)
- {
- unsigned int count;
- struct REGEX_INTERNAL_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);
- }
- /**
- * String container for faster string operations.
- */
- struct StringBuffer
- {
- /**
- * Buffer holding the string (may start in the middle!);
- * NOT 0-terminated!
- */
- char *sbuf;
- /**
- * Allocated buffer.
- */
- char *abuf;
- /**
- * Length of the string in the buffer.
- */
- size_t slen;
- /**
- * Number of bytes allocated for 'sbuf'
- */
- unsigned int blen;
- /**
- * Buffer currently represents "NULL" (not the empty string!)
- */
- int16_t null_flag;
- /**
- * If this entry is part of the last/current generation array,
- * this flag is GNUNET_YES if the last and current generation are
- * identical (and thus copying is unnecessary if the value didn't
- * change). This is used in an optimization that improves
- * performance by about 1% --- if we use int16_t here. With just
- * "int" for both flags, performance drops (on my system) significantly,
- * most likely due to increased cache misses.
- */
- int16_t synced;
- };
- /**
- * Compare two strings for equality. If either is NULL they are not equal.
- *
- * @param s1 first string for comparison.
- * @param s2 second string for comparison.
- *
- * @return 0 if the strings are the same or both NULL, 1 or -1 if not.
- */
- static int
- sb_nullstrcmp (const struct StringBuffer *s1,
- const struct StringBuffer *s2)
- {
- if ( (GNUNET_YES == s1->null_flag) &&
- (GNUNET_YES == s2->null_flag) )
- return 0;
- if ( (GNUNET_YES == s1->null_flag) ||
- (GNUNET_YES == s2->null_flag) )
- return -1;
- if (s1->slen != s2->slen)
- return -1;
- return memcmp (s1->sbuf, s2->sbuf, s1->slen);
- }
-
- /**
- * Compare two strings for equality.
- *
- * @param s1 first string for comparison.
- * @param s2 second string for comparison.
- *
- * @return 0 if the strings are the same, 1 or -1 if not.
- */
- static int
- sb_strcmp (const struct StringBuffer *s1,
- const struct StringBuffer *s2)
- {
- if (s1->slen != s2->slen)
- return -1;
- return memcmp (s1->sbuf, s2->sbuf, s1->slen);
- }
-
- /**
- * Reallocate the buffer of 'ret' to fit 'nlen' characters;
- * move the existing string to the beginning of the new buffer.
- *
- * @param ret current buffer, to be updated
- * @param nlen target length for the buffer, must be at least ret->slen
- */
- static void
- sb_realloc (struct StringBuffer *ret,
- size_t nlen)
- {
- char *old;
- GNUNET_assert (nlen >= ret->slen);
- old = ret->abuf;
- ret->abuf = GNUNET_malloc (nlen);
- ret->blen = nlen;
- memcpy (ret->abuf,
- ret->sbuf,
- ret->slen);
- ret->sbuf = ret->abuf;
- GNUNET_free_non_null (old);
- }
- /**
- * Append a string.
- *
- * @param ret where to write the result
- * @param sarg string to append
- */
- static void
- sb_append (struct StringBuffer *ret,
- const struct StringBuffer *sarg)
- {
- if (GNUNET_YES == ret->null_flag)
- ret->slen = 0;
- ret->null_flag = GNUNET_NO;
- if (ret->blen < sarg->slen + ret->slen)
- sb_realloc (ret, ret->blen + sarg->slen + 128);
- memcpy (&ret->sbuf[ret->slen],
- sarg->sbuf,
- sarg->slen);
- ret->slen += sarg->slen;
- }
-
- /**
- * Append a C string.
- *
- * @param ret where to write the result
- * @param cstr string to append
- */
- static void
- sb_append_cstr (struct StringBuffer *ret,
- const char *cstr)
- {
- size_t cstr_len = strlen (cstr);
- if (GNUNET_YES == ret->null_flag)
- ret->slen = 0;
- ret->null_flag = GNUNET_NO;
- if (ret->blen < cstr_len + ret->slen)
- sb_realloc (ret, ret->blen + cstr_len + 128);
- memcpy (&ret->sbuf[ret->slen],
- cstr,
- cstr_len);
- ret->slen += cstr_len;
- }
-
- /**
- * Wrap a string buffer, that is, set ret to the format string
- * which contains an "%s" which is to be replaced with the original
- * content of 'ret'. Note that optimizing this function is not
- * really worth it, it is rarely called.
- *
- * @param ret where to write the result and take the input for %.*s from
- * @param format format string, fprintf-style, with exactly one "%.*s"
- * @param extra_chars how long will the result be, in addition to 'sarg' length
- */
- static void
- sb_wrap (struct StringBuffer *ret,
- const char *format,
- size_t extra_chars)
- {
- char *temp;
- if (GNUNET_YES == ret->null_flag)
- ret->slen = 0;
- ret->null_flag = GNUNET_NO;
- temp = GNUNET_malloc (ret->slen + extra_chars + 1);
- GNUNET_snprintf (temp,
- ret->slen + extra_chars + 1,
- format,
- (int) ret->slen,
- ret->sbuf);
- GNUNET_free_non_null (ret->abuf);
- ret->abuf = temp;
- ret->sbuf = temp;
- ret->blen = ret->slen + extra_chars + 1;
- ret->slen = ret->slen + extra_chars;
- }
- /**
- * Format a string buffer. Note that optimizing this function is not
- * really worth it, it is rarely called.
- *
- * @param ret where to write the result
- * @param format format string, fprintf-style, with exactly one "%.*s"
- * @param extra_chars how long will the result be, in addition to 'sarg' length
- * @param sarg string to print into the format
- */
- static void
- sb_printf1 (struct StringBuffer *ret,
- const char *format,
- size_t extra_chars,
- const struct StringBuffer *sarg)
- {
- if (ret->blen < sarg->slen + extra_chars + 1)
- sb_realloc (ret,
- sarg->slen + extra_chars + 1);
- ret->null_flag = GNUNET_NO;
- ret->sbuf = ret->abuf;
- ret->slen = sarg->slen + extra_chars;
- GNUNET_snprintf (ret->sbuf,
- ret->blen,
- format,
- (int) sarg->slen,
- sarg->sbuf);
- }
- /**
- * Format a string buffer.
- *
- * @param ret where to write the result
- * @param format format string, fprintf-style, with exactly two "%.*s"
- * @param extra_chars how long will the result be, in addition to 'sarg1/2' length
- * @param sarg1 first string to print into the format
- * @param sarg2 second string to print into the format
- */
- static void
- sb_printf2 (struct StringBuffer *ret,
- const char *format,
- size_t extra_chars,
- const struct StringBuffer *sarg1,
- const struct StringBuffer *sarg2)
- {
- if (ret->blen < sarg1->slen + sarg2->slen + extra_chars + 1)
- sb_realloc (ret,
- sarg1->slen + sarg2->slen + extra_chars + 1);
- ret->null_flag = GNUNET_NO;
- ret->slen = sarg1->slen + sarg2->slen + extra_chars;
- ret->sbuf = ret->abuf;
- GNUNET_snprintf (ret->sbuf,
- ret->blen,
- format,
- (int) sarg1->slen,
- sarg1->sbuf,
- (int) sarg2->slen,
- sarg2->sbuf);
- }
- /**
- * Format a string buffer. Note that optimizing this function is not
- * really worth it, it is rarely called.
- *
- * @param ret where to write the result
- * @param format format string, fprintf-style, with exactly three "%.*s"
- * @param extra_chars how long will the result be, in addition to 'sarg1/2/3' length
- * @param sarg1 first string to print into the format
- * @param sarg2 second string to print into the format
- * @param sarg3 third string to print into the format
- */
- static void
- sb_printf3 (struct StringBuffer *ret,
- const char *format,
- size_t extra_chars,
- const struct StringBuffer *sarg1,
- const struct StringBuffer *sarg2,
- const struct StringBuffer *sarg3)
- {
- if (ret->blen < sarg1->slen + sarg2->slen + sarg3->slen + extra_chars + 1)
- sb_realloc (ret,
- sarg1->slen + sarg2->slen + sarg3->slen + extra_chars + 1);
- ret->null_flag = GNUNET_NO;
- ret->slen = sarg1->slen + sarg2->slen + sarg3->slen + extra_chars;
- ret->sbuf = ret->abuf;
- GNUNET_snprintf (ret->sbuf,
- ret->blen,
- format,
- (int) sarg1->slen,
- sarg1->sbuf,
- (int) sarg2->slen,
- sarg2->sbuf,
- (int) sarg3->slen,
- sarg3->sbuf);
- }
- /**
- * Free resources of the given string buffer.
- *
- * @param sb buffer to free (actual pointer is not freed, as they
- * should not be individually allocated)
- */
- static void
- sb_free (struct StringBuffer *sb)
- {
- GNUNET_array_grow (sb->abuf,
- sb->blen,
- 0);
- sb->slen = 0;
- sb->sbuf = NULL;
- sb->null_flag= GNUNET_YES;
- }
- /**
- * Copy the given string buffer from 'in' to 'out'.
- *
- * @param in input string
- * @param out output string
- */
- static void
- sb_strdup (struct StringBuffer *out,
- const struct StringBuffer *in)
-
- {
- out->null_flag = in->null_flag;
- if (GNUNET_YES == out->null_flag)
- return;
- if (out->blen < in->slen)
- {
- GNUNET_array_grow (out->abuf,
- out->blen,
- in->slen);
- }
- out->sbuf = out->abuf;
- out->slen = in->slen;
- memcpy (out->sbuf, in->sbuf, out->slen);
- }
- /**
- * Copy the given string buffer from 'in' to 'out'.
- *
- * @param cstr input string
- * @param out output string
- */
- static void
- sb_strdup_cstr (struct StringBuffer *out,
- const char *cstr)
- {
- if (NULL == cstr)
- {
- out->null_flag = GNUNET_YES;
- return;
- }
- out->null_flag = GNUNET_NO;
- out->slen = strlen (cstr);
- if (out->blen < out->slen)
- {
- GNUNET_array_grow (out->abuf,
- out->blen,
- out->slen);
- }
- out->sbuf = out->abuf;
- memcpy (out->sbuf, cstr, out->slen);
- }
- /**
- * Check if the given string 'str' needs parentheses around it when
- * using it to generate a regex.
- *
- * @param str string
- *
- * @return GNUNET_YES if parentheses are needed, GNUNET_NO otherwise
- */
- static int
- needs_parentheses (const struct StringBuffer *str)
- {
- size_t slen;
- const char *op;
- const char *cl;
- const char *pos;
- const char *end;
- unsigned int cnt;
- if ((GNUNET_YES == str->null_flag) || ((slen = str->slen) < 2))
- return GNUNET_NO;
- pos = str->sbuf;
- if ('(' != pos[0])
- return GNUNET_YES;
- end = str->sbuf + slen;
- cnt = 1;
- pos++;
- while (cnt > 0)
- {
- cl = memchr (pos, ')', end - pos);
- if (NULL == cl)
- {
- GNUNET_break (0);
- return GNUNET_YES;
- }
- /* while '(' before ')', count opening parens */
- while ( (NULL != (op = memchr (pos, '(', end - pos))) &&
- (op < cl) )
- {
- cnt++;
- pos = op + 1;
- }
- /* got ')' first */
- cnt--;
- pos = cl + 1;
- }
- return (*pos == '\0') ? GNUNET_NO : GNUNET_YES;
- }
- /**
- * Remove parentheses surrounding string 'str'.
- * Example: "(a)" becomes "a", "(a|b)|(a|c)" stays the same.
- * You need to GNUNET_free the returned string.
- *
- * @param str string, modified to contain a
- * @return string without surrounding parentheses, string 'str' if no preceding
- * epsilon could be found, NULL if 'str' was NULL
- */
- static void
- remove_parentheses (struct StringBuffer *str)
- {
- size_t slen;
- const char *pos;
- const char *end;
- const char *sbuf;
- const char *op;
- const char *cp;
- unsigned int cnt;
- if (0)
- return;
- sbuf = str->sbuf;
- if ( (GNUNET_YES == str->null_flag) ||
- (1 >= (slen = str->slen)) ||
- ('(' != str->sbuf[0]) ||
- (')' != str->sbuf[slen - 1]) )
- return;
- cnt = 0;
- pos = &sbuf[1];
- end = &sbuf[slen - 1];
- op = memchr (pos, '(', end - pos);
- cp = memchr (pos, ')', end - pos);
- while (NULL != cp)
- {
- while ( (NULL != op) &&
- (op < cp) )
- {
- cnt++;
- pos = op + 1;
- op = memchr (pos, '(', end - pos);
- }
- while ( (NULL != cp) &&
- ( (NULL == op) ||
- (cp < op) ) )
- {
- if (0 == cnt)
- return; /* can't strip parens */
- cnt--;
- pos = cp + 1;
- cp = memchr (pos, ')', end - pos);
- }
- }
- if (0 != cnt)
- {
- GNUNET_break (0);
- return;
- }
- str->sbuf++;
- str->slen -= 2;
- }
- /**
- * Check if the string 'str' starts with an epsilon (empty string).
- * Example: "(|a)" is starting with an epsilon.
- *
- * @param str string to test
- *
- * @return 0 if str has no epsilon, 1 if str starts with '(|' and ends with ')'
- */
- static int
- has_epsilon (const struct StringBuffer *str)
- {
- return
- (GNUNET_YES != str->null_flag) &&
- (0 < str->slen) &&
- ('(' == str->sbuf[0]) &&
- ('|' == str->sbuf[1]) &&
- (')' == str->sbuf[str->slen - 1]);
- }
- /**
- * Remove an epsilon from the string str. Where epsilon is an empty string
- * Example: str = "(|a|b|c)", result: "a|b|c"
- * The returned string needs to be freed.
- *
- * @param str original string
- * @param ret where to return string without preceding epsilon, string 'str' if no preceding
- * epsilon could be found, NULL if 'str' was NULL
- */
- static void
- remove_epsilon (const struct StringBuffer *str,
- struct StringBuffer *ret)
- {
- if (GNUNET_YES == str->null_flag)
- {
- ret->null_flag = GNUNET_YES;
- return;
- }
- if ( (str->slen > 1) &&
- ('(' == str->sbuf[0]) &&
- ('|' == str->sbuf[1]) &&
- (')' == str->sbuf[str->slen - 1]) )
- {
- /* remove epsilon */
- if (ret->blen < str->slen - 3)
- {
- GNUNET_array_grow (ret->abuf,
- ret->blen,
- str->slen - 3);
- }
- ret->sbuf = ret->abuf;
- ret->slen = str->slen - 3;
- memcpy (ret->sbuf, &str->sbuf[2], ret->slen);
- return;
- }
- sb_strdup (ret, str);
- }
- /**
- * Compare n bytes of 'str1' and 'str2'
- *
- * @param str1 first string to compare
- * @param str2 second string for comparison
- * @param n number of bytes to compare
- *
- * @return -1 if any of the strings is NULL, 0 if equal, non 0 otherwise
- */
- static int
- sb_strncmp (const struct StringBuffer *str1,
- const struct StringBuffer *str2, size_t n)
- {
- size_t max;
- if ( (str1->slen != str2->slen) &&
- ( (str1->slen < n) ||
- (str2->slen < n) ) )
- return -1;
- max = GNUNET_MAX (str1->slen, str2->slen);
- if (max > n)
- max = n;
- return memcmp (str1->sbuf, str2->sbuf, max);
- }
- /**
- * Compare n bytes of 'str1' and 'str2'
- *
- * @param str1 first string to compare
- * @param str2 second C string for comparison
- * @param n number of bytes to compare (and length of str2)
- *
- * @return -1 if any of the strings is NULL, 0 if equal, non 0 otherwise
- */
- static int
- sb_strncmp_cstr (const struct StringBuffer *str1,
- const char *str2, size_t n)
- {
- if (str1->slen < n)
- return -1;
- return memcmp (str1->sbuf, str2, n);
- }
- /**
- * Initialize string buffer for storing strings of up to n
- * characters.
- *
- * @param sb buffer to initialize
- * @param n desired target length
- */
- static void
- sb_init (struct StringBuffer *sb,
- size_t n)
- {
- sb->null_flag = GNUNET_NO;
- sb->abuf = sb->sbuf = (0 == n) ? NULL : GNUNET_malloc (n);
- sb->blen = n;
- sb->slen = 0;
- }
- /**
- * Compare 'str1', starting from position 'k', with whole 'str2'
- *
- * @param str1 first string to compare, starting from position 'k'
- * @param str2 second string for comparison
- * @param k starting position in 'str1'
- *
- * @return -1 if any of the strings is NULL, 0 if equal, non 0 otherwise
- */
- static int
- sb_strkcmp (const struct StringBuffer *str1,
- const struct StringBuffer *str2, size_t k)
- {
- if ( (GNUNET_YES == str1->null_flag) ||
- (GNUNET_YES == str2->null_flag) ||
- (k > str1->slen) ||
- (str1->slen - k != str2->slen) )
- return -1;
- return memcmp (&str1->sbuf[k], str2->sbuf, str2->slen);
- }
- /**
- * Helper function used as 'action' in 'REGEX_INTERNAL_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 REGEX_INTERNAL_State *s)
- {
- struct REGEX_INTERNAL_State **states = cls;
- s->dfs_id = count;
- if (NULL != states)
- states[count] = s;
- }
- #define PRIS(a) \
- ((GNUNET_YES == a.null_flag) ? 6 : (int) a.slen), \
- ((GNUNET_YES == a.null_flag) ? "(null)" : a.sbuf)
- /**
- * Construct the regular expression given the inductive step,
- * $R^{(k)}_{ij} = R^{(k-1)}_{ij} | R^{(k-1)}_{ik} ( R^{(k-1)}_{kk} )^*
- * R^{(k-1)}_{kj}, and simplify the resulting expression saved in R_cur_ij.
- *
- * @param R_last_ij value of $R^{(k-1)_{ij}.
- * @param R_last_ik value of $R^{(k-1)_{ik}.
- * @param R_last_kk value of $R^{(k-1)_{kk}.
- * @param R_last_kj value of $R^{(k-1)_{kj}.
- * @param R_cur_ij result for this inductive step is saved in R_cur_ij, R_cur_ij
- * is expected to be NULL when called!
- * @param R_cur_l optimization -- kept between iterations to avoid realloc
- * @param R_cur_r optimization -- kept between iterations to avoid realloc
- */
- static void
- automaton_create_proofs_simplify (const struct StringBuffer *R_last_ij,
- const struct StringBuffer *R_last_ik,
- const struct StringBuffer *R_last_kk,
- const struct StringBuffer *R_last_kj,
- struct StringBuffer *R_cur_ij,
- struct StringBuffer *R_cur_l,
- struct StringBuffer *R_cur_r)
- {
- struct StringBuffer R_temp_ij;
- struct StringBuffer R_temp_ik;
- struct StringBuffer R_temp_kj;
- struct StringBuffer R_temp_kk;
- int eps_check;
- int ij_ik_cmp;
- int ij_kj_cmp;
- int ik_kk_cmp;
- int kk_kj_cmp;
- int clean_ik_kk_cmp;
- int clean_kk_kj_cmp;
- size_t length;
- size_t length_l;
- size_t length_r;
- /*
- * $R^{(k)}_{ij} = R^{(k-1)}_{ij} | R^{(k-1)}_{ik} ( R^{(k-1)}_{kk} )^* R^{(k-1)}_{kj}
- * R_last == R^{(k-1)}, R_cur == R^{(k)}
- * R_cur_ij = R_cur_l | R_cur_r
- * R_cur_l == R^{(k-1)}_{ij}
- * R_cur_r == R^{(k-1)}_{ik} ( R^{(k-1)}_{kk} )^* R^{(k-1)}_{kj}
- */
- if ( (GNUNET_YES == R_last_ij->null_flag) &&
- ( (GNUNET_YES == R_last_ik->null_flag) ||
- (GNUNET_YES == R_last_kj->null_flag)))
- {
- /* R^{(k)}_{ij} = N | N */
- R_cur_ij->null_flag = GNUNET_YES;
- R_cur_ij->synced = GNUNET_NO;
- return;
- }
- if ( (GNUNET_YES == R_last_ik->null_flag) ||
- (GNUNET_YES == R_last_kj->null_flag) )
- {
- /* R^{(k)}_{ij} = R^{(k-1)}_{ij} | N */
- if (GNUNET_YES == R_last_ij->synced)
- {
- R_cur_ij->synced = GNUNET_YES;
- R_cur_ij->null_flag = GNUNET_NO;
- return;
- }
- R_cur_ij->synced = GNUNET_YES;
- sb_strdup (R_cur_ij, R_last_ij);
- return;
- }
- R_cur_ij->synced = GNUNET_NO;
- /* $R^{(k)}_{ij} = N | R^{(k-1)}_{ik} ( R^{(k-1)}_{kk} )^* R^{(k-1)}_{kj} OR
- * $R^{(k)}_{ij} = R^{(k-1)}_{ij} | R^{(k-1)}_{ik} ( R^{(k-1)}_{kk} )^* R^{(k-1)}_{kj} */
- R_cur_r->null_flag = GNUNET_YES;
- R_cur_r->slen = 0;
- R_cur_l->null_flag = GNUNET_YES;
- R_cur_l->slen = 0;
- /* cache results from strcmp, we might need these many times */
- ij_kj_cmp = sb_nullstrcmp (R_last_ij, R_last_kj);
- ij_ik_cmp = sb_nullstrcmp (R_last_ij, R_last_ik);
- ik_kk_cmp = sb_nullstrcmp (R_last_ik, R_last_kk);
- kk_kj_cmp = sb_nullstrcmp (R_last_kk, R_last_kj);
- /* Assign R_temp_(ik|kk|kj) to R_last[][] and remove epsilon as well
- * as parentheses, so we can better compare the contents */
- memset (&R_temp_ij, 0, sizeof (struct StringBuffer));
- memset (&R_temp_ik, 0, sizeof (struct StringBuffer));
- memset (&R_temp_kk, 0, sizeof (struct StringBuffer));
- memset (&R_temp_kj, 0, sizeof (struct StringBuffer));
- remove_epsilon (R_last_ik, &R_temp_ik);
- remove_epsilon (R_last_kk, &R_temp_kk);
- remove_epsilon (R_last_kj, &R_temp_kj);
- remove_parentheses (&R_temp_ik);
- remove_parentheses (&R_temp_kk);
- remove_parentheses (&R_temp_kj);
- clean_ik_kk_cmp = sb_nullstrcmp (R_last_ik, &R_temp_kk);
- clean_kk_kj_cmp = sb_nullstrcmp (&R_temp_kk, R_last_kj);
- /* construct R_cur_l (and, if necessary R_cur_r) */
- if (GNUNET_YES != R_last_ij->null_flag)
- {
- /* Assign R_temp_ij to R_last_ij and remove epsilon as well
- * as parentheses, so we can better compare the contents */
- remove_epsilon (R_last_ij, &R_temp_ij);
- remove_parentheses (&R_temp_ij);
- if ( (0 == sb_strcmp (&R_temp_ij, &R_temp_ik)) &&
- (0 == sb_strcmp (&R_temp_ik, &R_temp_kk)) &&
- (0 == sb_strcmp (&R_temp_kk, &R_temp_kj)) )
- {
- if (0 == R_temp_ij.slen)
- {
- R_cur_r->null_flag = GNUNET_NO;
- }
- else if ((0 == sb_strncmp_cstr (R_last_ij, "(|", 2)) ||
- (0 == sb_strncmp_cstr (R_last_ik, "(|", 2) &&
- 0 == sb_strncmp_cstr (R_last_kj, "(|", 2)))
- {
- /*
- * a|(e|a)a*(e|a) = a*
- * a|(e|a)(e|a)*(e|a) = a*
- * (e|a)|aa*a = a*
- * (e|a)|aa*(e|a) = a*
- * (e|a)|(e|a)a*a = a*
- * (e|a)|(e|a)a*(e|a) = a*
- * (e|a)|(e|a)(e|a)*(e|a) = a*
- */
- if (GNUNET_YES == needs_parentheses (&R_temp_ij))
- sb_printf1 (R_cur_r, "(%.*s)*", 3, &R_temp_ij);
- else
- sb_printf1 (R_cur_r, "%.*s*", 1, &R_temp_ij);
- }
- else
- {
- /*
- * a|aa*a = a+
- * a|(e|a)a*a = a+
- * a|aa*(e|a) = a+
- * a|(e|a)(e|a)*a = a+
- * a|a(e|a)*(e|a) = a+
- */
- if (GNUNET_YES == needs_parentheses (&R_temp_ij))
- sb_printf1 (R_cur_r, "(%.*s)+", 3, &R_temp_ij);
- else
- sb_printf1 (R_cur_r, "%.*s+", 1, &R_temp_ij);
- }
- }
- else if ( (0 == ij_ik_cmp) && (0 == clean_kk_kj_cmp) && (0 != clean_ik_kk_cmp) )
- {
- /* a|ab*b = ab* */
- if (0 == R_last_kk->slen)
- sb_strdup (R_cur_r, R_last_ij);
- else if (GNUNET_YES == needs_parentheses (&R_temp_kk))
- sb_printf2 (R_cur_r, "%.*s(%.*s)*", 3, R_last_ij, &R_temp_kk);
- else
- sb_printf2 (R_cur_r, "%.*s%.*s*", 1, R_last_ij, R_last_kk);
- R_cur_l->null_flag = GNUNET_YES;
- }
- else if ( (0 == ij_kj_cmp) && (0 == clean_ik_kk_cmp) && (0 != clean_kk_kj_cmp))
- {
- /* a|bb*a = b*a */
- if (R_last_kk->slen < 1)
- {
- sb_strdup (R_cur_r, R_last_kj);
- }
- else if (GNUNET_YES == needs_parentheses (&R_temp_kk))
- sb_printf2 (R_cur_r, "(%.*s)*%.*s", 3, &R_temp_kk, R_last_kj);
- else
- sb_printf2 (R_cur_r, "%.*s*%.*s", 1, &R_temp_kk, R_last_kj);
- R_cur_l->null_flag = GNUNET_YES;
- }
- else if ( (0 == ij_ik_cmp) && (0 == kk_kj_cmp) && (! has_epsilon (R_last_ij)) &&
- has_epsilon (R_last_kk))
- {
- /* a|a(e|b)*(e|b) = a|ab* = a|a|ab|abb|abbb|... = ab* */
- if (needs_parentheses (&R_temp_kk))
- sb_printf2 (R_cur_r, "%.*s(%.*s)*", 3, R_last_ij, &R_temp_kk);
- else
- sb_printf2 (R_cur_r, "%.*s%.*s*", 1, R_last_ij, &R_temp_kk);
- R_cur_l->null_flag = GNUNET_YES;
- }
- else if ( (0 == ij_kj_cmp) && (0 == ik_kk_cmp) && (! has_epsilon (R_last_ij)) &&
- has_epsilon (R_last_kk))
- {
- /* a|(e|b)(e|b)*a = a|b*a = a|a|ba|bba|bbba|... = b*a */
- if (needs_parentheses (&R_temp_kk))
- sb_printf2 (R_cur_r, "(%.*s)*%.*s", 3, &R_temp_kk, R_last_ij);
- else
- sb_printf2 (R_cur_r, "%.*s*%.*s", 1, &R_temp_kk, R_last_ij);
- R_cur_l->null_flag = GNUNET_YES;
- }
- else
- {
- sb_strdup (R_cur_l, R_last_ij);
- remove_parentheses (R_cur_l);
- }
- }
- else
- {
- /* we have no left side */
- R_cur_l->null_flag = GNUNET_YES;
- }
- /* construct R_cur_r, if not already constructed */
- if (GNUNET_YES == R_cur_r->null_flag)
- {
- length = R_temp_kk.slen - R_last_ik->slen;
- /* a(ba)*bx = (ab)+x */
- if ( (length > 0) &&
- (GNUNET_YES != R_last_kk->null_flag) &&
- (0 < R_last_kk->slen) &&
- (GNUNET_YES != R_last_kj->null_flag) &&
- (0 < R_last_kj->slen) &&
- (GNUNET_YES != R_last_ik->null_flag) &&
- (0 < R_last_ik->slen) &&
- (0 == sb_strkcmp (&R_temp_kk, R_last_ik, length)) &&
- (0 == sb_strncmp (&R_temp_kk, R_last_kj, length)) )
- {
- struct StringBuffer temp_a;
- struct StringBuffer temp_b;
- sb_init (&temp_a, length);
- sb_init (&temp_b, R_last_kj->slen - length);
- length_l = length;
- temp_a.sbuf = temp_a.abuf;
- memcpy (temp_a.sbuf, R_last_kj->sbuf, length_l);
- temp_a.slen = length_l;
- length_r = R_last_kj->slen - length;
- temp_b.sbuf = temp_b.abuf;
- memcpy (temp_b.sbuf, &R_last_kj->sbuf[length], length_r);
- temp_b.slen = length_r;
- /* e|(ab)+ = (ab)* */
- if ( (GNUNET_YES != R_cur_l->null_flag) &&
- (0 == R_cur_l->slen) &&
- (0 == temp_b.slen) )
- {
- sb_printf2 (R_cur_r, "(%.*s%.*s)*", 3, R_last_ik, &temp_a);
- sb_free (R_cur_l);
- R_cur_l->null_flag = GNUNET_YES;
- }
- else
- {
- sb_printf3 (R_cur_r, "(%.*s%.*s)+%.*s", 3, R_last_ik, &temp_a, &temp_b);
- }
- sb_free (&temp_a);
- sb_free (&temp_b);
- }
- else if (0 == sb_strcmp (&R_temp_ik, &R_temp_kk) &&
- 0 == sb_strcmp (&R_temp_kk, &R_temp_kj))
- {
- /*
- * (e|a)a*(e|a) = a*
- * (e|a)(e|a)*(e|a) = a*
- */
- if (has_epsilon (R_last_ik) && has_epsilon (R_last_kj))
- {
- if (needs_parentheses (&R_temp_kk))
- sb_printf1 (R_cur_r, "(%.*s)*", 3, &R_temp_kk);
- else
- sb_printf1 (R_cur_r, "%.*s*", 1, &R_temp_kk);
- }
- /* aa*a = a+a */
- else if ( (0 == clean_ik_kk_cmp) &&
- (0 == clean_kk_kj_cmp) &&
- (! has_epsilon (R_last_ik)) )
- {
- if (needs_parentheses (&R_temp_kk))
- sb_printf2 (R_cur_r, "(%.*s)+%.*s", 3, &R_temp_kk, &R_temp_kk);
- else
- sb_printf2 (R_cur_r, "%.*s+%.*s", 1, &R_temp_kk, &R_temp_kk);
- }
- /*
- * (e|a)a*a = a+
- * aa*(e|a) = a+
- * a(e|a)*(e|a) = a+
- * (e|a)a*a = a+
- */
- else
- {
- eps_check =
- (has_epsilon (R_last_ik) + has_epsilon (R_last_kk) +
- has_epsilon (R_last_kj));
- if (1 == eps_check)
- {
- if (needs_parentheses (&R_temp_kk))
- sb_printf1 (R_cur_r, "(%.*s)+", 3, &R_temp_kk);
- else
- sb_printf1 (R_cur_r, "%.*s+", 1, &R_temp_kk);
- }
- }
- }
- /*
- * aa*b = a+b
- * (e|a)(e|a)*b = a*b
- */
- else if (0 == sb_strcmp (&R_temp_ik, &R_temp_kk))
- {
- if (has_epsilon (R_last_ik))
- {
- if (needs_parentheses (&R_temp_kk))
- sb_printf2 (R_cur_r, "(%.*s)*%.*s", 3, &R_temp_kk, R_last_kj);
- else
- sb_printf2 (R_cur_r, "%.*s*%.*s", 1, &R_temp_kk, R_last_kj);
- }
- else
- {
- if (needs_parentheses (&R_temp_kk))
- sb_printf2 (R_cur_r, "(%.*s)+%.*s", 3, &R_temp_kk, R_last_kj);
- else
- sb_printf2 (R_cur_r, "%.*s+%.*s", 1, &R_temp_kk, R_last_kj);
- }
- }
- /*
- * ba*a = ba+
- * b(e|a)*(e|a) = ba*
- */
- else if (0 == sb_strcmp (&R_temp_kk, &R_temp_kj))
- {
- if (has_epsilon (R_last_kj))
- {
- if (needs_parentheses (&R_temp_kk))
- sb_printf2 (R_cur_r, "%.*s(%.*s)*", 3, R_last_ik, &R_temp_kk);
- else
- sb_printf2 (R_cur_r, "%.*s%.*s*", 1, R_last_ik, &R_temp_kk);
- }
- else
- {
- if (needs_parentheses (&R_temp_kk))
- sb_printf2 (R_cur_r, "(%.*s)+%.*s", 3, R_last_ik, &R_temp_kk);
- else
- sb_printf2 (R_cur_r, "%.*s+%.*s", 1, R_last_ik, &R_temp_kk);
- }
- }
- else
- {
- if (0 < R_temp_kk.slen)
- {
- if (needs_parentheses (&R_temp_kk))
- {
- sb_printf3 (R_cur_r, "%.*s(%.*s)*%.*s", 3, R_last_ik, &R_temp_kk,
- R_last_kj);
- }
- else
- {
- sb_printf3 (R_cur_r, "%.*s%.*s*%.*s", 1, R_last_ik, &R_temp_kk,
- R_last_kj);
- }
- }
- else
- {
- sb_printf2 (R_cur_r, "%.*s%.*s", 0, R_last_ik, R_last_kj);
- }
- }
- }
- sb_free (&R_temp_ij);
- sb_free (&R_temp_ik);
- sb_free (&R_temp_kk);
- sb_free (&R_temp_kj);
- if ( (GNUNET_YES == R_cur_l->null_flag) &&
- (GNUNET_YES == R_cur_r->null_flag) )
- {
- R_cur_ij->null_flag = GNUNET_YES;
- return;
- }
- if ( (GNUNET_YES != R_cur_l->null_flag) &&
- (GNUNET_YES == R_cur_r->null_flag) )
- {
- struct StringBuffer tmp;
- tmp = *R_cur_ij;
- *R_cur_ij = *R_cur_l;
- *R_cur_l = tmp;
- return;
- }
- if ( (GNUNET_YES == R_cur_l->null_flag) &&
- (GNUNET_YES != R_cur_r->null_flag) )
- {
- struct StringBuffer tmp;
- tmp = *R_cur_ij;
- *R_cur_ij = *R_cur_r;
- *R_cur_r = tmp;
- return;
- }
- if (0 == sb_nullstrcmp (R_cur_l, R_cur_r))
- {
- struct StringBuffer tmp;
- tmp = *R_cur_ij;
- *R_cur_ij = *R_cur_l;
- *R_cur_l = tmp;
- return;
- }
- sb_printf2 (R_cur_ij, "(%.*s|%.*s)", 3, R_cur_l, R_cur_r);
- }
- /**
- * Create proofs for all states in the given automaton. Implementation of the
- * algorithm descriped in chapter 3.2.1 of "Automata Theory, Languages, and
- * Computation 3rd Edition" by Hopcroft, Motwani and Ullman.
- *
- * Each state in the automaton gets assigned 'proof' and 'hash' (hash of the
- * proof) fields. The starting state will only have a valid proof/hash if it has
- * any incoming transitions.
- *
- * @param a automaton for which to assign proofs and hashes, must not be NULL
- */
- static int
- automaton_create_proofs (struct REGEX_INTERNAL_Automaton *a)
- {
- unsigned int n = a->state_count;
- struct REGEX_INTERNAL_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 REGEX_INTERNAL_Transition *t;
- struct StringBuffer complete_regex;
- unsigned int i;
- unsigned int j;
- unsigned int k;
- R_last = GNUNET_malloc_large (sizeof (struct StringBuffer) * n * n);
- R_cur = GNUNET_malloc_large (sizeof (struct StringBuffer) * n * n);
- if ( (NULL == R_last) ||
- (NULL == R_cur) )
- {
- GNUNET_log_strerror (GNUNET_ERROR_TYPE_ERROR, "malloc");
- GNUNET_free_non_null (R_cur);
- GNUNET_free_non_null (R_last);
- return GNUNET_SYSERR;
- }
- /* create depth-first numbering of the states, initializes 'state' */
- REGEX_INTERNAL_automaton_traverse (a, a->start, NULL, NULL, &number_states,
- states);
- for (i = 0; i < n; i++)
- GNUNET_assert (NULL != states[i]);
- for (i = 0; i < n; i++)
- for (j = 0; j < n; j++)
- R_last[i *n + j].null_flag = GNUNET_YES;
- /* Compute regular expressions of length "1" between each pair of states */
- for (i = 0; i < n; i++)
- {
- for (t = states[i]->transitions_head; NULL != t; t = t->next)
- {
- j = t->to_state->dfs_id;
- if (GNUNET_YES == R_last[i * n + j].null_flag)
- {
- sb_strdup_cstr (&R_last[i * n + j], t->label);
- }
- else
- {
- sb_append_cstr (&R_last[i * n + j], "|");
- sb_append_cstr (&R_last[i * n + j], t->label);
- }
- }
- /* add self-loop: i is reachable from i via epsilon-transition */
- if (GNUNET_YES == R_last[i * n + i].null_flag)
- {
- R_last[i * n + i].slen = 0;
- R_last[i * n + i].null_flag = GNUNET_NO;
- }
- else
- {
- sb_wrap (&R_last[i * n + i], "(|%.*s)", 3);
- }
- }
- for (i = 0; i < n; i++)
- for (j = 0; j < n; j++)
- if (needs_parentheses (&R_last[i * n + j]))
- sb_wrap (&R_last[i * n + j], "(%.*s)", 2);
- /* Compute regular expressions of length "k" between each pair of states per
- * induction */
- memset (&R_cur_l, 0, sizeof (struct StringBuffer));
- memset (&R_cur_r, 0, sizeof (struct StringBuffer));
- for (k = 0; k < n; k++)
- {
- for (i = 0; i < n; i++)
- {
- for (j = 0; j < n; j++)
- {
- /* Basis for the recursion:
- * $R^{(k)}_{ij} = R^{(k-1)}_{ij} | R^{(k-1)}_{ik} ( R^{(k-1)}_{kk} )^* R^{(k-1)}_{kj}
- * R_last == R^{(k-1)}, R_cur == R^{(k)}
- */
- /* Create R_cur[i][j] and simplify the expression */
- automaton_create_proofs_simplify (&R_last[i * n + j], &R_last[i * n + k],
- &R_last[k * n + k], &R_last[k * n + j],
- &R_cur[i * n + j],
- &R_cur_l, &R_cur_r);
- }
- }
- /* set R_last = R_cur */
- R_swap = R_last;
- R_last = R_cur;
- R_cur = R_swap;
- /* clear 'R_cur' for next iteration */
- for (i = 0; i < n; i++)
- for (j = 0; j < n; j++)
- R_cur[i * n + j].null_flag = GNUNET_YES;
- }
- sb_free (&R_cur_l);
- sb_free (&R_cur_r);
- /* assign proofs and hashes */
- for (i = 0; i < n; i++)
- {
- if (GNUNET_YES != R_last[a->start->dfs_id * n + i].null_flag)
- {
- states[i]->proof = GNUNET_strndup (R_last[a->start->dfs_id * n + i].sbuf,
- R_last[a->start->dfs_id * n + i].slen);
- GNUNET_CRYPTO_hash (states[i]->proof, strlen (states[i]->proof),
- &states[i]->hash);
- }
- }
- /* complete regex for whole DFA: union of all pairs (start state/accepting
- * state(s)). */
- sb_init (&complete_regex, 16 * n);
- for (i = 0; i < n; i++)
- {
- if (states[i]->accepting)
- {
- if ( (0 == complete_regex.slen) &&
- (0 < R_last[a->start->dfs_id * n + i].slen) )
- {
- sb_append (&complete_regex,
- &R_last[a->start->dfs_id * n + i]);
- }
- else if ( (GNUNET_YES != R_last[a->start->dfs_id * n + i].null_flag) &&
- (0 < R_last[a->start->dfs_id * n + i].slen) )
- {
- sb_append_cstr (&complete_regex, "|");
- sb_append (&complete_regex,
- &R_last[a->start->dfs_id * n + i]);
- }
- }
- }
- a->canonical_regex = GNUNET_strndup (complete_regex.sbuf, complete_regex.slen);
- /* cleanup */
- sb_free (&complete_regex);
- for (i = 0; i < n; i++)
- for (j = 0; j < n; j++)
- {
- sb_free (&R_cur[i * n + j]);
- sb_free (&R_last[i * n + j]);
- }
- GNUNET_free (R_cur);
- GNUNET_free (R_last);
- return GNUNET_OK;
- }
- /**
- * Creates a new DFA state based on a set of NFA states. Needs to be freed using
- * automaton_destroy_state.
- *
- * @param ctx context
- * @param nfa_states set of NFA states on which the DFA should be based on
- *
- * @return new DFA state
- */
- static struct REGEX_INTERNAL_State *
- dfa_state_create (struct REGEX_INTERNAL_Context *ctx,
- struct REGEX_INTERNAL_StateSet *nfa_states)
- {
- struct REGEX_INTERNAL_State *s;
- char *pos;
- size_t len;
- struct REGEX_INTERNAL_State *cstate;
- struct REGEX_INTERNAL_Transition *ctran;
- unsigned int i;
- s = GNUNET_new (struct REGEX_INTERNAL_State);
- s->id = ctx->state_id++;
- s->index = -1;
- s->lowlink = -1;
- if (NULL == nfa_states)
- {
- GNUNET_asprintf (&s->name, "s%i", s->id);
- return s;
- }
- s->nfa_set = *nfa_states;
- if (nfa_states->off < 1)
- return s;
- /* Create a name based on 'nfa_states' */
- len = nfa_states->off * 14 + 4;
- s->name = GNUNET_malloc (len);
- strcat (s->name, "{");
- pos = s->name + 1;
- for (i = 0; i < nfa_states->off; i++)
- {
- cstate = nfa_states->states[i];
- GNUNET_snprintf (pos, pos - s->name + len,
- "%i,", cstate->id);
- pos += strlen (pos);
- /* 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 (cstate->accepting)
- s->accepting = 1;
- }
- pos[-1] = '}';
- s->name = GNUNET_realloc (s->name, strlen (s->name) + 1);
- memset (nfa_states, 0, sizeof (struct REGEX_INTERNAL_StateSet));
- return s;
- }
- /**
- * 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, will point to the next state or NULL (if no
- * transition possible)
- * @param str edge label to follow (will match longest common prefix)
- *
- * @return length of the substring comsumed from 'str'
- */
- static unsigned int
- dfa_move (struct REGEX_INTERNAL_State **s, const char *str)
- {
- struct REGEX_INTERNAL_Transition *t;
- struct REGEX_INTERNAL_State *new_s;
- unsigned int len;
- unsigned int max_len;
- if (NULL == s)
- return 0;
- new_s = NULL;
- max_len = 0;
- for (t = (*s)->transitions_head; NULL != t; t = t->next)
- {
- len = strlen (t->label);
- if (0 == strncmp (t->label, str, len))
- {
- if (len >= max_len)
- {
- max_len = len;
- new_s = t->to_state;
- }
- }
- }
- *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 REGEX_INTERNAL_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.
- *
- * @param a DFA automaton
- */
- static void
- dfa_remove_unreachable_states (struct REGEX_INTERNAL_Automaton *a)
- {
- struct REGEX_INTERNAL_State *s;
- struct REGEX_INTERNAL_State *s_next;
- /* 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 */
- REGEX_INTERNAL_automaton_traverse (a, a->start, NULL, NULL, &mark_states, NULL);
- /* 3. delete all states that were not visited */
- for (s = a->states_head; NULL != s; s = s_next)
- {
- s_next = s->next;
- if (GNUNET_NO == s->marked)
- automaton_remove_state (a, s);
- }
- }
- /**
- * Remove all dead states from the DFA 'a'. Dead states are those states that do
- * not transition to any other state but themselves.
- *
- * @param a DFA automaton
- */
- static void
- dfa_remove_dead_states (struct REGEX_INTERNAL_Automaton *a)
- {
- struct REGEX_INTERNAL_State *s;
- struct REGEX_INTERNAL_State *s_next;
- struct REGEX_INTERNAL_Transition *t;
- int dead;
- GNUNET_assert (DFA == a->type);
- for (s = a->states_head; NULL != s; s = s_next)
- {
- s_next = s->next;
- if (s->accepting)
- continue;
- dead = 1;
- for (t = s->transitions_head; NULL != t; t = t->next)
- {
- if (NULL != t->to_state && t->to_state != s)
- {
- dead = 0;
- break;
- }
- }
- if (0 == dead)
- continue;
- /* state s is dead, remove it */
- automaton_remove_state (a, s);
- }
- }
- /**
- * Merge all non distinguishable states in the DFA 'a'
- *
- * @param ctx context
- * @param a DFA automaton
- * @return GNUNET_OK on success
- */
- static int
- dfa_merge_nondistinguishable_states (struct REGEX_INTERNAL_Context *ctx,
- struct REGEX_INTERNAL_Automaton *a)
- {
- uint32_t *table;
- struct REGEX_INTERNAL_State *s1;
- struct REGEX_INTERNAL_State *s2;
- struct REGEX_INTERNAL_Transition *t1;
- struct REGEX_INTERNAL_Transition *t2;
- struct REGEX_INTERNAL_State *s1_next;
- struct REGEX_INTERNAL_State *s2_next;
- int change;
- unsigned int num_equal_edges;
- unsigned int i;
- unsigned int state_cnt;
- unsigned long long idx;
- unsigned long long idx1;
- if ( (NULL == a) || (0 == a->state_count) )
- {
- GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
- "Could not merge nondistinguishable states, automaton was NULL.\n");
- return GNUNET_SYSERR;
- }
- state_cnt = a->state_count;
- table = GNUNET_malloc_large ((sizeof (uint32_t) * state_cnt * state_cnt / 32) + sizeof (uint32_t));
- if (NULL == table)
- {
- GNUNET_log_strerror (GNUNET_ERROR_TYPE_ERROR, "malloc");
- return GNUNET_SYSERR;
- }
- for (i = 0, s1 = a->states_head; NULL != s1; s1 = s1->next)
- s1->marked = i++;
- /* Mark all pairs of accepting/!accepting states */
- for (s1 = a->states_head; NULL != s1; s1 = s1->next)
- for (s2 = a->states_head; NULL != s2; s2 = s2->next)
- if ( (s1->accepting && !s2->accepting) ||
- (!s1->accepting && s2->accepting) )
- {
- idx = s1->marked * state_cnt + s2->marked;
- table[idx / 32] |= (1 << (idx % 32));
- }
- /* Find all equal states */
- change = 1;
- while (0 != change)
- {
- change = 0;
- for (s1 = a->states_head; NULL != s1; s1 = s1->next)
- {
- for (s2 = a->states_head; NULL != s2 && s1 != s2; s2 = s2->next)
- {
- 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 (0 == strcmp (t1->label, t2->label))
- {
- num_equal_edges++;
- /* same edge, but targets definitively different, so we're different
- as well */
- if (t1->to_state->marked > t2->to_state->marked)
- idx1 = t1->to_state->marked * state_cnt + t2->to_state->marked;
- else
- idx1 = t2->to_state->marked * state_cnt + t1->to_state->marked;
- if (0 != (table[idx1 / 32] & (1 << (idx1 % 32))))
- {
- table[idx / 32] |= (1 << (idx % 32));
- change = 1; /* changed a marker, need to run again */
- }
- }
- }
- }
- if ( (num_equal_edges != s1->transition_count) ||
- (num_equal_edges != s2->transition_count) )
- {
- /* Make sure ALL edges of possible equal states are the same */
- table[idx / 32] |= (1 << (idx % 32));
- change = 1; /* changed a marker, need to run again */
- }
- }
- }
- }
- /* 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;
- 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 int
- dfa_minimize (struct REGEX_INTERNAL_Context *ctx,
- struct REGEX_INTERNAL_Automaton *a)
- {
- if (NULL == a)
- return GNUNET_SYSERR;
- GNUNET_assert (DFA == a->type);
- /* 1. remove unreachable states */
- dfa_remove_unreachable_states (a);
- /* 2. remove dead states */
- dfa_remove_dead_states (a);
- /* 3. Merge nondistinguishable states */
- if (GNUNET_OK != dfa_merge_nondistinguishable_states (ctx, a))
- return GNUNET_SYSERR;
- return GNUNET_OK;
- }
- /**
- * Context for adding strided transitions to a DFA.
- */
- struct REGEX_INTERNAL_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 REGEX_INTERNAL_Transition *transitions_head;
- /**
- * Strided transitions DLL.
- */
- struct REGEX_INTERNAL_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
- */
- static void
- dfa_add_multi_strides_helper (void *cls, const unsigned int depth, char *label,
- struct REGEX_INTERNAL_State *start,
- struct REGEX_INTERNAL_State *s)
- {
- struct REGEX_INTERNAL_Strided_Context *ctx = cls;
- struct REGEX_INTERNAL_Transition *t;
- char *new_label;
- if (depth == ctx->stride)
- {
- t = GNUNET_new (struct REGEX_INTERNAL_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.
- */
- static void
- dfa_add_multi_strides (void *cls, const unsigned int count,
- struct REGEX_INTERNAL_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
- REGEX_INTERNAL_dfa_add_multi_strides (struct REGEX_INTERNAL_Context *regex_ctx,
- struct REGEX_INTERNAL_Automaton *dfa,
- const unsigned int stride_len)
- {
- struct REGEX_INTERNAL_Strided_Context ctx = { stride_len, NULL, NULL };
- struct REGEX_INTERNAL_Transition *t;
- struct REGEX_INTERNAL_Transition *t_next;
- if (1 > stride_len || GNUNET_YES == dfa->is_multistrided)
- return;
- /* Compute the new transitions of given stride_len */
- REGEX_INTERNAL_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 REGEX_INTERNAL_Automaton *dfa,
- struct REGEX_INTERNAL_State *start,
- struct REGEX_INTERNAL_State *cur, char *label,
- unsigned int max_len,
- struct REGEX_INTERNAL_Transition **transitions_head,
- struct REGEX_INTERNAL_Transition **transitions_tail)
- {
- struct REGEX_INTERNAL_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_new (struct REGEX_INTERNAL_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 REGEX_INTERNAL_Context *regex_ctx,
- struct REGEX_INTERNAL_Automaton *dfa, unsigned int max_len)
- {
- struct REGEX_INTERNAL_State *s;
- struct REGEX_INTERNAL_State *s_next;
- struct REGEX_INTERNAL_Transition *t;
- struct REGEX_INTERNAL_Transition *t_next;
- struct REGEX_INTERNAL_Transition *transitions_head = NULL;
- struct REGEX_INTERNAL_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.
- *
- * @param start starting state
- * @param end end state
- *
- * @return new NFA fragment
- */
- static struct REGEX_INTERNAL_Automaton *
- nfa_fragment_create (struct REGEX_INTERNAL_State *start,
- struct REGEX_INTERNAL_State *end)
- {
- struct REGEX_INTERNAL_Automaton *n;
- n = GNUNET_new (struct REGEX_INTERNAL_Automaton);
- n->type = NFA;
- n->start = NULL;
- n->end = NULL;
- n->state_count = 0;
- 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'.
- *
- * @param n automaton to which the states should be added
- * @param states_head head of the DLL of states
- * @param states_tail tail of the DLL of states
- */
- static void
- nfa_add_states (struct REGEX_INTERNAL_Automaton *n,
- struct REGEX_INTERNAL_State *states_head,
- struct REGEX_INTERNAL_State *states_tail)
- {
- struct REGEX_INTERNAL_State *s;
- if (NULL == n || NULL == states_head)
- {
- GNUNET_log (GNUNET_ERROR_TYPE_ERROR, "Could not add states\n");
- return;
- }
- if (NULL == n->states_head)
- {
- n->states_head = states_head;
- n->states_tail = states_tail;
- return;
- }
- if (NULL != states_head)
- {
- n->states_tail->next = states_head;
- n->states_tail = states_tail;
- }
- for (s = states_head; NULL != s; s = s->next)
- n->state_count++;
- }
- /**
- * Creates a new NFA state. Needs to be freed using automaton_destroy_state.
- *
- * @param ctx context
- * @param accepting is it an accepting state or not
- *
- * @return new NFA state
- */
- static struct REGEX_INTERNAL_State *
- nfa_state_create (struct REGEX_INTERNAL_Context *ctx, int accepting)
- {
- struct REGEX_INTERNAL_State *s;
- s = GNUNET_new (struct REGEX_INTERNAL_State);
- s->id = ctx->state_id++;
- s->accepting = accepting;
- s->marked = GNUNET_NO;
- s->contained = 0;
- s->index = -1;
- s->lowlink = -1;
- s->scc_id = 0;
- s->name = NULL;
- GNUNET_asprintf (&s->name, "s%i", s->id);
- return s;
- }
- /**
- * 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 NULL for epsilon transition
- */
- static void
- nfa_closure_set_create (struct REGEX_INTERNAL_StateSet *ret,
- struct REGEX_INTERNAL_Automaton *nfa,
- struct REGEX_INTERNAL_StateSet *states, const char *label)
- {
- struct REGEX_INTERNAL_State *s;
- unsigned int i;
- struct REGEX_INTERNAL_StateSet_MDLL cls_stack;
- struct REGEX_INTERNAL_State *clsstate;
- struct REGEX_INTERNAL_State *currentstate;
- struct REGEX_INTERNAL_Transition *ctran;
- memset (ret, 0, sizeof (struct REGEX_INTERNAL_StateSet));
- if (NULL == states)
- return;
- for (i = 0; i < states->off; i++)
- {
- s = states->states[i];
- /* 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))
- {
- 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 (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;
- }
- }
- }
- for (i = 0; i < ret->off; i++)
- ret->states[i]->contained = 0;
- if (ret->off > 1)
- qsort (ret->states, ret->off, sizeof (struct REGEX_INTERNAL_State *),
- &state_compare);
- }
- /**
- * Pops two NFA fragments (a, b) from the stack and concatenates them (ab)
- *
- * @param ctx context
- */
- static void
- nfa_add_concatenation (struct REGEX_INTERNAL_Context *ctx)
- {
- struct REGEX_INTERNAL_Automaton *a;
- struct REGEX_INTERNAL_Automaton *b;
- struct REGEX_INTERNAL_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, NULL, b->start);
- a->end->accepting = 0;
- b->end->accepting = 1;
- 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_nfa);
- }
- /**
- * Pops a NFA fragment from the stack (a) and adds a new fragment (a*)
- *
- * @param ctx context
- */
- static void
- nfa_add_star_op (struct REGEX_INTERNAL_Context *ctx)
- {
- struct REGEX_INTERNAL_Automaton *a;
- struct REGEX_INTERNAL_Automaton *new_nfa;
- struct REGEX_INTERNAL_State *start;
- struct REGEX_INTERNAL_State *end;
- a = ctx->stack_tail;
- if (NULL == a)
- {
- GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
- "nfa_add_star_op failed, because there was no element on the stack");
- 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, 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 = 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_nfa);
- }
- /**
- * Pops an NFA fragment (a) from the stack and adds a new fragment (a+)
- *
- * @param ctx context
- */
- static void
- nfa_add_plus_op (struct REGEX_INTERNAL_Context *ctx)
- {
- struct REGEX_INTERNAL_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, 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?)
- *
- * @param ctx context
- */
- static void
- nfa_add_question_op (struct REGEX_INTERNAL_Context *ctx)
- {
- struct REGEX_INTERNAL_Automaton *a;
- struct REGEX_INTERNAL_Automaton *new_nfa;
- struct REGEX_INTERNAL_State *start;
- struct REGEX_INTERNAL_State *end;
- a = ctx->stack_tail;
- if (NULL == a)
- {
- GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
- "nfa_add_question_op failed, because there was no element on the stack");
- 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, NULL, a->start);
- state_add_transition (ctx, start, NULL, end);
- state_add_transition (ctx, a->end, NULL, end);
- a->end->accepting = 0;
- 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);
- }
- /**
- * Pops two NFA fragments (a, b) from the stack and adds a new NFA fragment that
- * alternates between a and b (a|b)
- *
- * @param ctx context
- */
- static void
- nfa_add_alternation (struct REGEX_INTERNAL_Context *ctx)
- {
- struct REGEX_INTERNAL_Automaton *a;
- struct REGEX_INTERNAL_Automaton *b;
- struct REGEX_INTERNAL_Automaton *new_nfa;
- struct REGEX_INTERNAL_State *start;
- struct REGEX_INTERNAL_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, NULL, a->start);
- state_add_transition (ctx, start, NULL, b->start);
- 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 = 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_nfa);
- }
- /**
- * Adds a new nfa fragment to the stack
- *
- * @param ctx context
- * @param label label for nfa transition
- */
- static void
- nfa_add_label (struct REGEX_INTERNAL_Context *ctx, const char *label)
- {
- struct REGEX_INTERNAL_Automaton *n;
- struct REGEX_INTERNAL_State *start;
- struct REGEX_INTERNAL_State *end;
- GNUNET_assert (NULL != ctx);
- start = nfa_state_create (ctx, 0);
- end = nfa_state_create (ctx, 1);
- 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
- *
- * @param ctx context
- */
- static void
- REGEX_INTERNAL_context_init (struct REGEX_INTERNAL_Context *ctx)
- {
- if (NULL == ctx)
- {
- GNUNET_log (GNUNET_ERROR_TYPE_ERROR, "Context was NULL!");
- return;
- }
- ctx->state_id = 0;
- ctx->transition_id = 0;
- ctx->stack_head = NULL;
- ctx->stack_tail = NULL;
- }
- /**
- * Construct an NFA by parsing the regex string of length 'len'.
- *
- * @param regex regular expression string
- * @param len length of the string
- *
- * @return NFA, needs to be freed using REGEX_INTERNAL_destroy_automaton
- */
- struct REGEX_INTERNAL_Automaton *
- REGEX_INTERNAL_construct_nfa (const char *regex, const size_t len)
- {
- struct REGEX_INTERNAL_Context ctx;
- struct REGEX_INTERNAL_Automaton *nfa;
- const char *regexp;
- char curlabel[2];
- char *error_msg;
- unsigned int count;
- unsigned int altcount;
- unsigned int atomcount;
- 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;
- }
- REGEX_INTERNAL_context_init (&ctx);
- regexp = regex;
- curlabel[1] = '\0';
- p = NULL;
- error_msg = NULL;
- altcount = 0;
- atomcount = 0;
- poff = 0;
- psize = 0;
- for (count = 0; count < len && *regexp; count++, regexp++)
- {
- switch (*regexp)
- {
- case '(':
- if (atomcount > 1)
- {
- --atomcount;
- nfa_add_concatenation (&ctx);
- }
- if (poff == psize)
- GNUNET_array_grow (p, psize, psize * 2 + 4); /* FIXME why *2 +4? */
- p[poff].altcount = altcount;
- p[poff].atomcount = atomcount;
- poff++;
- altcount = 0;
- atomcount = 0;
- break;
- case '|':
- if (0 == atomcount)
- {
- error_msg = "Cannot append '|' to nothing";
- goto error;
- }
- while (--atomcount > 0)
- nfa_add_concatenation (&ctx);
- altcount++;
- break;
- case ')':
- if (0 == poff)
- {
- error_msg = "Missing opening '('";
- goto error;
- }
- if (0 == 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);
- poff--;
- altcount = p[poff].altcount;
- atomcount = p[poff].atomcount;
- atomcount++;
- break;
- case '*':
- if (atomcount == 0)
- {
- error_msg = "Cannot append '*' to nothing";
- goto error;
- }
- nfa_add_star_op (&ctx);
- break;
- case '+':
- if (atomcount == 0)
- {
- error_msg = "Cannot append '+' to nothing";
- goto error;
- }
- nfa_add_plus_op (&ctx);
- break;
- case '?':
- if (atomcount == 0)
- {
- error_msg = "Cannot append '?' to nothing";
- goto error;
- }
- nfa_add_question_op (&ctx);
- break;
- default:
- if (atomcount > 1)
- {
- --atomcount;
- nfa_add_concatenation (&ctx);
- }
- curlabel[0] = *regexp;
- nfa_add_label (&ctx, curlabel);
- atomcount++;
- break;
- }
- }
- if (0 != poff)
- {
- error_msg = "Unbalanced parenthesis";
- goto error;
- }
- while (--atomcount > 0)
- nfa_add_concatenation (&ctx);
- for (; altcount > 0; altcount--)
- nfa_add_alternation (&ctx);
- GNUNET_array_grow (p, psize, 0);
- nfa = ctx.stack_tail;
- GNUNET_CONTAINER_DLL_remove (ctx.stack_head, ctx.stack_tail, nfa);
- if (NULL != ctx.stack_head)
- {
- error_msg = "Creating the NFA failed. NFA stack was not empty!";
- goto error;
- }
- /* Remember the regex that was used to generate this NFA */
- nfa->regex = GNUNET_strdup (regex);
- /* create depth-first numbering of the states for pretty printing */
- REGEX_INTERNAL_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: `%s'\n", regex);
- if (NULL != error_msg)
- GNUNET_log (GNUNET_ERROR_TYPE_ERROR, "%s\n", error_msg);
- GNUNET_free_non_null (p);
- while (NULL != (nfa = ctx.stack_head))
- {
- GNUNET_CONTAINER_DLL_remove (ctx.stack_head, ctx.stack_tail, nfa);
- REGEX_INTERNAL_automaton_destroy (nfa);
- }
- return NULL;
- }
- /**
- * Create DFA states based on given 'nfa' and starting with 'dfa_state'.
- *
- * @param ctx context.
- * @param nfa NFA automaton.
- * @param dfa DFA automaton.
- * @param dfa_state current dfa state, pass epsilon closure of first nfa state
- * for starting.
- */
- static void
- construct_dfa_states (struct REGEX_INTERNAL_Context *ctx,
- struct REGEX_INTERNAL_Automaton *nfa,
- struct REGEX_INTERNAL_Automaton *dfa,
- struct REGEX_INTERNAL_State *dfa_state)
- {
- struct REGEX_INTERNAL_Transition *ctran;
- struct REGEX_INTERNAL_State *new_dfa_state;
- struct REGEX_INTERNAL_State *state_contains;
- struct REGEX_INTERNAL_State *state_iter;
- struct REGEX_INTERNAL_StateSet tmp;
- struct REGEX_INTERNAL_StateSet nfa_set;
- for (ctran = dfa_state->transitions_head; NULL != ctran; ctran = ctran->next)
- {
- if (NULL == ctran->label || NULL != ctran->to_state)
- continue;
- 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, &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);
- }
- else
- {
- ctran->to_state = state_contains;
- state_set_clear (&nfa_set);
- }
- }
- }
- /**
- * 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 REGEX_INTERNAL_automaton_destroy.
- */
- struct REGEX_INTERNAL_Automaton *
- REGEX_INTERNAL_construct_dfa (const char *regex, const size_t len,
- unsigned int max_path_len)
- {
- struct REGEX_INTERNAL_Context ctx;
- struct REGEX_INTERNAL_Automaton *dfa;
- struct REGEX_INTERNAL_Automaton *nfa;
- struct REGEX_INTERNAL_StateSet nfa_start_eps_cls;
- struct REGEX_INTERNAL_StateSet singleton_set;
- REGEX_INTERNAL_context_init (&ctx);
- /* Create NFA */
- nfa = REGEX_INTERNAL_construct_nfa (regex, len);
- if (NULL == nfa)
- {
- GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
- "Could not create DFA, because NFA creation failed\n");
- return NULL;
- }
- dfa = GNUNET_new (struct REGEX_INTERNAL_Automaton);
- dfa->type = DFA;
- dfa->regex = GNUNET_strdup (regex);
- /* Create DFA start state from epsilon closure */
- memset (&singleton_set, 0, sizeof (struct REGEX_INTERNAL_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);
- construct_dfa_states (&ctx, nfa, dfa, dfa->start);
- REGEX_INTERNAL_automaton_destroy (nfa);
- /* Minimize DFA */
- if (GNUNET_OK != dfa_minimize (&ctx, dfa))
- {
- REGEX_INTERNAL_automaton_destroy (dfa);
- return NULL;
- }
- /* Create proofs and hashes for all states */
- if (GNUNET_OK != automaton_create_proofs (dfa))
- {
- REGEX_INTERNAL_automaton_destroy (dfa);
- return NULL;
- }
- /* Compress linear DFA paths */
- if (1 != max_path_len)
- dfa_compress_paths (&ctx, dfa, max_path_len);
- return dfa;
- }
- /**
- * Free the memory allocated by constructing the REGEX_INTERNAL_Automaton data
- * structure.
- *
- * @param a automaton to be destroyed
- */
- void
- REGEX_INTERNAL_automaton_destroy (struct REGEX_INTERNAL_Automaton *a)
- {
- struct REGEX_INTERNAL_State *s;
- struct REGEX_INTERNAL_State *next_state;
- if (NULL == a)
- return;
- 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);
- }
- GNUNET_free (a);
- }
- /**
- * Evaluates the given string using the given DFA automaton
- *
- * @param a automaton, type must be DFA
- * @param string string that should be evaluated
- *
- * @return 0 if string matches, non 0 otherwise
- */
- static int
- evaluate_dfa (struct REGEX_INTERNAL_Automaton *a, const char *string)
- {
- const char *strp;
- struct REGEX_INTERNAL_State *s;
- unsigned int step_len;
- if (DFA != a->type)
- {
- GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
- "Tried to evaluate DFA, but NFA automaton given");
- return -1;
- }
- s = a->start;
- /* 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)
- {
- step_len = dfa_move (&s, strp);
- if (NULL == s)
- break;
- }
- if (NULL != s && s->accepting)
- return 0;
- return 1;
- }
- /**
- * Evaluates the given string using the given NFA automaton
- *
- * @param a automaton, type must be NFA
- * @param string string that should be evaluated
- *
- * @return 0 if string matches, non 0 otherwise
- */
- static int
- evaluate_nfa (struct REGEX_INTERNAL_Automaton *a, const char *string)
- {
- const char *strp;
- char str[2];
- struct REGEX_INTERNAL_State *s;
- struct REGEX_INTERNAL_StateSet sset;
- struct REGEX_INTERNAL_StateSet new_sset;
- struct REGEX_INTERNAL_StateSet singleton_set;
- unsigned int i;
- int result;
- if (NFA != a->type)
- {
- GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
- "Tried to evaluate NFA, but DFA automaton given");
- 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;
- memset (&singleton_set, 0, sizeof (struct REGEX_INTERNAL_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++)
- {
- 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.off; i++)
- {
- s = sset.states[i];
- if ( (NULL != s) && (s->accepting) )
- {
- result = 0;
- break;
- }
- }
- state_set_clear (&sset);
- return result;
- }
- /**
- * Evaluates the given 'string' against the given compiled regex
- *
- * @param a automaton
- * @param string string to check
- *
- * @return 0 if string matches, non 0 otherwise
- */
- int
- REGEX_INTERNAL_eval (struct REGEX_INTERNAL_Automaton *a, const char *string)
- {
- int result;
- switch (a->type)
- {
- case DFA:
- result = evaluate_dfa (a, string);
- break;
- case NFA:
- result = evaluate_nfa (a, string);
- break;
- default:
- GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
- "Evaluating regex failed, automaton has no type!\n");
- result = GNUNET_SYSERR;
- break;
- }
- return result;
- }
- /**
- * 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 *
- REGEX_INTERNAL_get_canonical_regex (struct REGEX_INTERNAL_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
- REGEX_INTERNAL_get_transition_count (struct REGEX_INTERNAL_Automaton *a)
- {
- unsigned int t_count;
- struct REGEX_INTERNAL_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_string'.
- *
- * @param input_string string.
- * @param string_len length of the 'input_string'.
- * @param key pointer to where to write the hash code.
- *
- * @return number of bits of 'input_string' that have been consumed
- * to construct the key
- */
- size_t
- REGEX_INTERNAL_get_first_key (const char *input_string, size_t string_len,
- struct GNUNET_HashCode * key)
- {
- size_t size;
- size = string_len < GNUNET_REGEX_INITIAL_BYTES ? string_len :
- GNUNET_REGEX_INITIAL_BYTES;
- if (NULL == input_string)
- {
- GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
- "Given input string was NULL!\n");
- return 0;
- }
- GNUNET_CRYPTO_hash (input_string, size, key);
- return size;
- }
- /**
- * Recursive function that calls the iterator for each synthetic start 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 for the iterator function.
- */
- static void
- iterate_initial_edge (const unsigned int min_len, const unsigned int max_len,
- char *consumed_string, struct REGEX_INTERNAL_State *state,
- REGEX_INTERNAL_KeyIterator iterator, void *iterator_cls)
- {
- char *temp;
- struct REGEX_INTERNAL_Transition *t;
- unsigned int num_edges = state->transition_count;
- struct REGEX_BLOCK_Edge edges[num_edges];
- struct REGEX_BLOCK_Edge edge[1];
- struct GNUNET_HashCode hash;
- struct GNUNET_HashCode hash_new;
- unsigned int cur_len;
- if (NULL != consumed_string)
- cur_len = strlen (consumed_string);
- else
- cur_len = 0;
- if ((cur_len >= min_len || GNUNET_YES == state->accepting) && cur_len > 0 &&
- NULL != consumed_string)
- {
- if (cur_len <= max_len)
- {
- if (state->proof != NULL && 0 != strcmp (consumed_string, state->proof))
- {
- (void) state_get_edges (state, edges);
- GNUNET_CRYPTO_hash (consumed_string, strlen (consumed_string), &hash);
- iterator (iterator_cls, &hash, consumed_string, state->accepting,
- num_edges, 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 /* cur_len > max_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);
- }
- }
- 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);
- 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.
- *
- * @param a automaton.
- * @param iterator iterator called for each edge.
- * @param iterator_cls closure.
- */
- void
- REGEX_INTERNAL_iterate_all_edges (struct REGEX_INTERNAL_Automaton *a,
- REGEX_INTERNAL_KeyIterator iterator,
- void *iterator_cls)
- {
- struct REGEX_INTERNAL_State *s;
- for (s = a->states_head; NULL != s; s = s->next)
- {
- struct REGEX_BLOCK_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);
- }
- /**
- * Struct to hold all the relevant state information in the HashMap.
- *
- * Contains the same info as the Regex Iterator parametes except the key,
- * which comes directly from the HashMap iterator.
- */
- struct temporal_state_store {
- int reachable;
- char *proof;
- int accepting;
- int num_edges;
- struct REGEX_BLOCK_Edge *edges;
- };
- /**
- * Store regex iterator and cls in one place to pass to the hashmap iterator.
- */
- struct client_iterator {
- REGEX_INTERNAL_KeyIterator iterator;
- void *iterator_cls;
- };
- /**
- * Iterator over all edges of a dfa. Stores all of them in a HashMap
- * for later reachability marking.
- *
- * @param cls Closure (HashMap)
- * @param key hash for current state.
- * @param proof proof for current state
- * @param accepting GNUNET_YES if this is an accepting state, GNUNET_NO if not.
- * @param num_edges number of edges leaving current state.
- * @param edges edges leaving current state.
- */
- static void
- store_all_states (void *cls,
- const struct GNUNET_HashCode *key,
- const char *proof,
- int accepting,
- unsigned int num_edges,
- const struct REGEX_BLOCK_Edge *edges)
- {
- struct GNUNET_CONTAINER_MultiHashMap *hm = cls;
- struct temporal_state_store *tmp;
- size_t edges_size;
- tmp = GNUNET_new (struct temporal_state_store);
- tmp->reachable = GNUNET_NO;
- tmp->proof = GNUNET_strdup (proof);
- tmp->accepting = accepting;
- tmp->num_edges = num_edges;
- edges_size = sizeof (struct REGEX_BLOCK_Edge) * num_edges;
- tmp->edges = GNUNET_malloc (edges_size);
- memcpy(tmp->edges, edges, edges_size);
- GNUNET_CONTAINER_multihashmap_put (hm, key, tmp,
- GNUNET_CONTAINER_MULTIHASHMAPOPTION_UNIQUE_FAST);
- }
- /**
- * Mark state as reachable and call recursively on all its edges.
- *
- * If already marked as reachable, do nothing.
- *
- * @param state State to mark as reachable.
- * @param hm HashMap which stores all the states indexed by key.
- */
- static void
- mark_as_reachable (struct temporal_state_store *state,
- struct GNUNET_CONTAINER_MultiHashMap *hm)
- {
- struct temporal_state_store *child;
- unsigned int i;
- if (GNUNET_YES == state->reachable)
- /* visited */
- return;
- state->reachable = GNUNET_YES;
- for (i = 0; i < state->num_edges; i++)
- {
- child = GNUNET_CONTAINER_multihashmap_get (hm,
- &state->edges[i].destination);
- if (NULL == child)
- {
- GNUNET_break (0);
- continue;
- }
- mark_as_reachable (child, hm);
- }
- }
- /**
- * Iterator over hash map entries to mark the ones that are reachable.
- *
- * @param cls closure
- * @param key current key code
- * @param value value in the hash map
- * @return #GNUNET_YES if we should continue to iterate,
- * #GNUNET_NO if not.
- */
- static int
- reachability_iterator (void *cls,
- const struct GNUNET_HashCode *key,
- void *value)
- {
- struct GNUNET_CONTAINER_MultiHashMap *hm = cls;
- struct temporal_state_store *state = value;
- if (GNUNET_YES == state->reachable)
- /* already visited and marked */
- return GNUNET_YES;
- if (GNUNET_REGEX_INITIAL_BYTES > strlen (state->proof) &&
- GNUNET_NO == state->accepting)
- /* not directly reachable */
- return GNUNET_YES;
- mark_as_reachable (state, hm);
- return GNUNET_YES;
- }
- /**
- * Iterator over hash map entries.
- * Calling the callback on the ones marked as reachables.
- *
- * @param cls closure
- * @param key current key code
- * @param value value in the hash map
- * @return #GNUNET_YES if we should continue to iterate,
- * #GNUNET_NO if not.
- */
- static int
- iterate_reachables (void *cls,
- const struct GNUNET_HashCode *key,
- void *value)
- {
- struct client_iterator *ci = cls;
- struct temporal_state_store *state = value;
- if (GNUNET_YES == state->reachable)
- {
- ci->iterator (ci->iterator_cls, key,
- state->proof, state->accepting,
- state->num_edges, state->edges);
- }
- GNUNET_free (state->edges);
- GNUNET_free (state->proof);
- GNUNET_free (state);
- return GNUNET_YES;
- }
- /**
- * Iterate over all edges of automaton 'a' that are reachable from a state with
- * a proof of at least GNUNET_REGEX_INITIAL_BYTES characters.
- *
- * Call the iterator for each such edge.
- *
- * @param a automaton.
- * @param iterator iterator called for each reachable edge.
- * @param iterator_cls closure.
- */
- void
- REGEX_INTERNAL_iterate_reachable_edges (struct REGEX_INTERNAL_Automaton *a,
- REGEX_INTERNAL_KeyIterator iterator,
- void *iterator_cls)
- {
- struct GNUNET_CONTAINER_MultiHashMap *hm;
- struct client_iterator ci;
- hm = GNUNET_CONTAINER_multihashmap_create (a->state_count * 2, GNUNET_NO);
- ci.iterator = iterator;
- ci.iterator_cls = iterator_cls;
- REGEX_INTERNAL_iterate_all_edges (a, &store_all_states, hm);
- GNUNET_CONTAINER_multihashmap_iterate (hm, &reachability_iterator, hm);
- GNUNET_CONTAINER_multihashmap_iterate (hm, &iterate_reachables, &ci);
- GNUNET_CONTAINER_multihashmap_destroy (hm);
- }
- /* end of regex_internal.c */
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