removing unreachable states

diff --git a/src/regex/regex.c b/src/regex/regex.c
index fc9de529c7531591682579e26fe53b95ff5c7511..080e5d31e26f3c80f210b017b17ede0c209583d8 100644 (file)
--- a/src/regex/regex.c
+++ b/src/regex/regex.c
@@ -298,6 +298,7 @@ automaton_fragment_clear (struct GNUNET_REGEX_Automaton *a)
   a->end = NULL;
   a->states_head = NULL;
   a->states_tail = NULL;
+  a->state_count = 0;
   GNUNET_free (a);
 }
 
@@ -328,6 +329,23 @@ automaton_destroy_state (struct State *s)
   GNUNET_free (s);
 }
 
+static void
+automaton_remove_state (struct GNUNET_REGEX_Automaton *a, struct State *s)
+{
+  struct State *ss;
+  ss = s;
+  GNUNET_CONTAINER_DLL_remove (a->states_head, a->states_tail, s);
+  a->state_count--;
+  automaton_destroy_state (ss);
+}
+
+static void
+automaton_add_state (struct GNUNET_REGEX_Automaton *a, struct State *s)
+{
+  GNUNET_CONTAINER_DLL_insert (a->states_head, a->states_tail, s);
+  a->state_count++;
+}
+
 /**
  * Creates a new DFA state based on a set of NFA states. Needs to be freed
  * using automaton_destroy_state.
@@ -457,34 +475,44 @@ dfa_move (struct State *s, const char literal)
 static void
 dfa_remove_unreachable_states (struct GNUNET_REGEX_Automaton *a)
 {
-  /*
-   * struct StateSet *unreachable;
-   * struct State *stack[a->size];
-   * struct State *s;
-   *
-   * unreachable = GNUNET_malloc (sizeof (struct StateSet));
-   *
-   * // 1. add all states to unreachable set
-   * for (s = a->states_head; NULL != s; s = s->next)
-   * {
-   * GNUNET_array_append (unreachable->states, unreachable->len; s);
-   * }
-   *
-   * // 2. traverse dfa from start state and remove every visited state from unreachable set
-   * s = a->start;
-   * // push a->start
-   * while (stack->len > 0)
-   * {
-   * s = stack->states[stack->len - 1];
-   * GNUNET_array_grow (stack->states; stack->len; stack->len-1);
-   * GNUNET_array_
-   * for (t = s->transitions_head; NULL != t; t = t->next)
-   * {
-   *
-   * }
-   * }
-   * // 3. delete all states that are still in the unreachable set
-   */
+  struct State *stack[a->state_count];
+  int stack_len;
+  struct State *s;
+  struct Transition *t;
+
+  stack_len = 0;
+
+  // 1. unmark all states
+  for (s = a->states_head; NULL != s; s = s->next)
+  {
+    s->marked = 0;
+  }
+
+  // 2. traverse dfa from start state and mark all visited states
+  stack[stack_len] = a->start;
+  stack_len++;
+  while (stack_len > 0)
+  {
+    s = stack[stack_len-1];
+    stack_len--;
+    s->marked = 1; // mark s as visited
+    for (t = s->transitions_head; NULL != t; t = t->next)
+    {
+      if (NULL != t->state && 0 == t->state->marked)
+      {
+        // add next states to stack
+        stack[stack_len] = t->state;
+        stack_len++;
+      }
+    }
+  }
+
+  // 3. delete all states that were not visited
+  for (s = a->states_head; NULL != s; s = s->next)
+  {
+    if (0 == s->marked)
+      automaton_remove_state (a, s);
+  }
 }
 
 /**
@@ -537,7 +565,7 @@ dfa_remove_dead_states (struct GNUNET_REGEX_Automaton *a)
       }
     }
     // 2. remove state
-    GNUNET_CONTAINER_DLL_remove (a->states_head, a->states_tail, s);
+    automaton_remove_state (a, s);
   }
 }
 
@@ -595,8 +623,8 @@ nfa_fragment_create (struct State *start, struct State *end)
   if (NULL == start && NULL == end)
     return n;
 
-  GNUNET_CONTAINER_DLL_insert (n->states_head, n->states_tail, end);
-  GNUNET_CONTAINER_DLL_insert (n->states_head, n->states_tail, start);
+  automaton_add_state (n, end);
+  automaton_add_state (n, start);
 
   n->start = start;
   n->end = end;
@@ -615,6 +643,8 @@ static void
 nfa_add_states (struct GNUNET_REGEX_Automaton *n, struct State *states_head,
                 struct State *states_tail)
 {
+  struct State *s;
+
   if (NULL == n || NULL == states_head)
   {
     GNUNET_log (GNUNET_ERROR_TYPE_ERROR, "Could not add states\n");
@@ -633,6 +663,9 @@ nfa_add_states (struct GNUNET_REGEX_Automaton *n, struct State *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++;
 }
 
 /**
@@ -1137,7 +1170,7 @@ GNUNET_REGEX_construct_dfa (const char *regex, const size_t len)
   dfa_stack = GNUNET_malloc (sizeof (struct StateSet));
   nfa_set = nfa_closure_create (nfa->start, 0);
   dfa->start = dfa_state_create (&ctx, nfa_set);
-  GNUNET_CONTAINER_DLL_insert (dfa->states_head, dfa->states_tail, dfa->start);
+  automaton_add_state (dfa, dfa->start);
   GNUNET_array_append (dfa_stack->states, dfa_stack->len, dfa->start);
   while (dfa_stack->len > 0)
   {
@@ -1164,8 +1197,7 @@ GNUNET_REGEX_construct_dfa (const char *regex, const size_t len)
 
         if (NULL == state_contains)
         {
-          GNUNET_CONTAINER_DLL_insert_tail (dfa->states_head, dfa->states_tail,
-                                            new_dfa_state);
+          automaton_add_state (dfa, new_dfa_state);
           GNUNET_array_append (dfa_stack->states, dfa_stack->len,
                                new_dfa_state);
           ctran->state = new_dfa_state;

diff --git a/src/regex/test_regex.c b/src/regex/test_regex.c
index d4e4e1ec56edd01ac3b04c06d8c845f8fa2bc8d0..4c08c7c53a6254ca638df7fa8212176233349ec6 100644 (file)
--- a/src/regex/test_regex.c
+++ b/src/regex/test_regex.c
@@ -156,6 +156,7 @@ test_random (unsigned int rx_length, unsigned int max_str_len, unsigned int str_
     }
 
     eval_check = regexec (&rx, matching_str[i], 1, matchptr, 0);
+    regfree (&rx);
 
     // We only want to match the whole string, because that's what our DFA does, too.
     if (eval_check == 0 && (matchptr[0].rm_so != 0 || matchptr[0].rm_eo != strlen (matching_str[i])))
@@ -210,8 +211,10 @@ test_automaton (struct GNUNET_REGEX_Automaton *a, regex_t *rx, struct Regex_Stri
         result = 1;
         regerror (eval_check, rx, error, sizeof error);
         GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
-                    "Unexpected result:\nregex: %s\nstring: %s\nexpected result: %i\ngnunet regex: %i\nglibc regex: %i\nglibc error: %s\nrm_so: %i\nrm_eo: %i\n\n",
-                    rxstr->regex, rxstr->strings[i], rxstr->expected_results[i], eval, eval_check, error, matchptr[0].rm_so, matchptr[0].rm_eo);
+                    "Unexpected result:\nregex: %s\nstring: %s\nexpected result: %i\n"
+                    "gnunet regex: %i\nglibc regex: %i\nglibc error: %s\nrm_so: %i\nrm_eo: %i\n\n",
+                    rxstr->regex, rxstr->strings[i], rxstr->expected_results[i],
+                    eval, eval_check, error, matchptr[0].rm_so, matchptr[0].rm_eo);
     }
   }
   return result;
@@ -228,6 +231,9 @@ main (int argc, char *argv[])
 #endif
                     NULL);
 
+  struct GNUNET_REGEX_Automaton *a;
+  regex_t rx;
+  int i;
   int check_nfa;
   int check_dfa;
   int check_rand;
@@ -238,9 +244,6 @@ main (int argc, char *argv[])
     {"ab+c*(a(bx|c)d)+", 5, 
      {"abcdcdcdcdddddabd", "abcd", "abcddddddccccccccccccccccccccccccabdacdabd", "abccccca", "abcdcdcdccdabdabd"}, 
      {nomatch, nomatch, nomatch, nomatch, nomatch}}};
-  struct GNUNET_REGEX_Automaton *a;
-  regex_t rx;
-  int i;
 
   check_nfa = 0;
   check_dfa = 0;
@@ -269,7 +272,7 @@ main (int argc, char *argv[])
 
   srand (time(NULL));
   for (i=0; i< 100; i++)
-    check_rand += test_random (100, 100, 10);
+    check_rand += test_random (100, 150, 10);
 
   return check_nfa + check_dfa + check_rand;
 }