X-Git-Url: http://info.iut-bm.univ-fcomte.fr/pub/gitweb/simgrid.git/blobdiff_plain/22f0a9f34379900e70aac6953273e71344d8ca0d..2376a01092173679830310f4d57b267445959f97:/src/mc/mc_visited.cpp

diff --git a/src/mc/mc_visited.cpp b/src/mc/mc_visited.cpp
index e8e6922f25..ee5d9ee4c4 100644
--- a/src/mc/mc_visited.cpp
+++ b/src/mc/mc_visited.cpp
@@ -7,489 +7,133 @@
 #include <unistd.h>
 #include <sys/wait.h>
 
-#include "mc_comm_pattern.h"
-#include "mc_safety.h"
-#include "mc_liveness.h"
-#include "mc_private.h"
-#include "mc/Process.hpp"
-#include "mc_smx.h"
+#include <memory>
+#include <algorithm>
 
-extern "C" {
+#include <xbt/log.h>
+#include <xbt/sysdep.h>
+#include <xbt/dynar.h>
+#include <xbt/dynar.hpp>
+#include <xbt/fifo.h>
+
+#include "src/mc/mc_comm_pattern.h"
+#include "src/mc/mc_safety.h"
+#include "src/mc/mc_private.h"
+#include "src/mc/Process.hpp"
+#include "src/mc/mc_smx.h"
 
 XBT_LOG_NEW_DEFAULT_SUBCATEGORY(mc_visited, mc,
                                 "Logging specific to state equaity detection mechanisms");
 
-xbt_dynar_t visited_pairs;
-xbt_dynar_t visited_states;
+namespace simgrid {
+namespace mc {
 
-static int is_exploration_stack_state(mc_visited_state_t state){
-  xbt_fifo_item_t item = xbt_fifo_get_first_item(mc_stack);
-  while (item) {
-    if (((mc_state_t)xbt_fifo_get_item_content(item))->num == state->num){
-      ((mc_state_t)xbt_fifo_get_item_content(item))->in_visited_states = 0;
-      return 1;
-    }
-    item = xbt_fifo_get_next_item(item);
-  }
-  return 0;
-}
-
-void visited_state_free(mc_visited_state_t state)
-{
-  if (state) {
-    if(!is_exploration_stack_state(state))
-      delete state->system_state;
-    xbt_free(state);
-  }
-}
-
-void visited_state_free_voidp(void *s)
-{
-  visited_state_free((mc_visited_state_t) * (void **) s);
-}
+std::vector<std::unique_ptr<simgrid::mc::VisitedState>> visited_states;
 
 /**
  * \brief Save the current state
  * \return Snapshot of the current state.
  */
-static mc_visited_state_t visited_state_new()
+VisitedState::VisitedState()
 {
   simgrid::mc::Process* process = &(mc_model_checker->process());
-  mc_visited_state_t new_state = xbt_new0(s_mc_visited_state_t, 1);
-  new_state->heap_bytes_used = mmalloc_get_bytes_used_remote(
+  this->heap_bytes_used = mmalloc_get_bytes_used_remote(
     process->get_heap()->heaplimit,
     process->get_malloc_info());
 
-  MC_process_smx_refresh(&mc_model_checker->process());
-  new_state->nb_processes = xbt_dynar_length(
-    mc_model_checker->process().smx_process_infos);
+  this->nb_processes =
+    mc_model_checker->process().simix_processes().size();
 
-  new_state->system_state = MC_take_snapshot(mc_stats->expanded_states);
-  new_state->num = mc_stats->expanded_states;
-  new_state->other_num = -1;
-  return new_state;
+  this->system_state = simgrid::mc::take_snapshot(mc_stats->expanded_states);
+  this->num = mc_stats->expanded_states;
+  this->other_num = -1;
 }
 
-mc_visited_pair_t MC_visited_pair_new(int pair_num, xbt_automaton_state_t automaton_state, xbt_dynar_t atomic_propositions, mc_state_t graph_state)
+VisitedState::~VisitedState()
 {
-  simgrid::mc::Process* process = &(mc_model_checker->process());
-  mc_visited_pair_t pair = NULL;
-  pair = xbt_new0(s_mc_visited_pair_t, 1);
-  pair->graph_state = graph_state;
-  if(pair->graph_state->system_state == NULL)
-    pair->graph_state->system_state = MC_take_snapshot(pair_num);
-  pair->heap_bytes_used = mmalloc_get_bytes_used_remote(
-    process->get_heap()->heaplimit,
-    process->get_malloc_info());
-
-  MC_process_smx_refresh(&mc_model_checker->process());
-  pair->nb_processes = xbt_dynar_length(
-    mc_model_checker->process().smx_process_infos);
-
-  pair->automaton_state = automaton_state;
-  pair->num = pair_num;
-  pair->other_num = -1;
-  pair->acceptance_removed = 0;
-  pair->visited_removed = 0;
-  pair->acceptance_pair = 0;
-  pair->atomic_propositions = xbt_dynar_new(sizeof(int), NULL);
-  unsigned int cursor = 0;
-  int value;
-  xbt_dynar_foreach(atomic_propositions, cursor, value)
-      xbt_dynar_push_as(pair->atomic_propositions, int, value);
-  return pair;
-}
-
-static int is_exploration_stack_pair(mc_visited_pair_t pair){
-  xbt_fifo_item_t item = xbt_fifo_get_first_item(mc_stack);
-  while (item) {
-    if (((mc_pair_t)xbt_fifo_get_item_content(item))->num == pair->num){
-      ((mc_pair_t)xbt_fifo_get_item_content(item))->visited_pair_removed = 1;
-      return 1;
-    }
-    item = xbt_fifo_get_next_item(item);
-  }
-  return 0;
 }
 
-void MC_visited_pair_delete(mc_visited_pair_t p)
+static void prune_visited_states()
 {
-  p->automaton_state = NULL;
-  if( !is_exploration_stack_pair(p))
-    MC_state_delete(p->graph_state, 1);
-  xbt_dynar_free(&(p->atomic_propositions));
-  xbt_free(p);
-  p = NULL;
-}
-
-/**
- *  \brief Find a suitable subrange of candidate duplicates for a given state
- *  \param list dynamic array of states/pairs with candidate duplicates of the current state;
- *  \param ref current state/pair;
- *  \param min (output) index of the beginning of the the subrange
- *  \param max (output) index of the enf of the subrange
- *
- *  Given a suitably ordered array of states/pairs, this function extracts a subrange
- *  (with index *min <= i <= *max) with candidate duplicates of the given state/pair.
- *  This function uses only fast discriminating criterions and does not use the
- *  full state/pair comparison algorithms.
- *
- *  The states/pairs in list MUST be ordered using a (given) weak order
- *  (based on nb_processes and heap_bytes_used).
- *  The subrange is the subrange of "equivalence" of the given state/pair.
- */
-int get_search_interval(xbt_dynar_t list, void *ref, int *min, int *max)
-{
-  int cursor = 0, previous_cursor;
-  int nb_processes, heap_bytes_used, nb_processes_test, heap_bytes_used_test;
-  void *ref_test;
-
-  if (_sg_mc_liveness) {
-    nb_processes = ((mc_visited_pair_t) ref)->nb_processes;
-    heap_bytes_used = ((mc_visited_pair_t) ref)->heap_bytes_used;
-  } else {
-    nb_processes = ((mc_visited_state_t) ref)->nb_processes;
-    heap_bytes_used = ((mc_visited_state_t) ref)->heap_bytes_used;
-  }
-
-  int start = 0;
-  int end = xbt_dynar_length(list) - 1;
-
-  while (start <= end) {
-    cursor = (start + end) / 2;
-    if (_sg_mc_liveness) {
-      ref_test = (mc_visited_pair_t) xbt_dynar_get_as(list, cursor, mc_visited_pair_t);
-      nb_processes_test = ((mc_visited_pair_t) ref_test)->nb_processes;
-      heap_bytes_used_test = ((mc_visited_pair_t) ref_test)->heap_bytes_used;
-    } else {
-      ref_test = (mc_visited_state_t) xbt_dynar_get_as(list, cursor, mc_visited_state_t);
-      nb_processes_test = ((mc_visited_state_t) ref_test)->nb_processes;
-      heap_bytes_used_test = ((mc_visited_state_t) ref_test)->heap_bytes_used;
-    }
-    if (nb_processes_test < nb_processes) {
-      start = cursor + 1;
-    } else if (nb_processes_test > nb_processes) {
-      end = cursor - 1;
-    } else {
-      if (heap_bytes_used_test < heap_bytes_used) {
-        start = cursor + 1;
-      } else if (heap_bytes_used_test > heap_bytes_used) {
-        end = cursor - 1;
-      } else {
-        *min = *max = cursor;
-        previous_cursor = cursor - 1;
-        while (previous_cursor >= 0) {
-          if (_sg_mc_liveness) {
-            ref_test = (mc_visited_pair_t) xbt_dynar_get_as(list, previous_cursor, mc_visited_pair_t);
-            nb_processes_test = ((mc_visited_pair_t) ref_test)->nb_processes;
-            heap_bytes_used_test = ((mc_visited_pair_t) ref_test)->heap_bytes_used;
-          } else {
-            ref_test = (mc_visited_state_t) xbt_dynar_get_as(list, previous_cursor, mc_visited_state_t);
-            nb_processes_test = ((mc_visited_state_t) ref_test)->nb_processes;
-            heap_bytes_used_test = ((mc_visited_state_t) ref_test)->heap_bytes_used;
-          }
-          if (nb_processes_test != nb_processes || heap_bytes_used_test != heap_bytes_used)
-            break;
-          *min = previous_cursor;
-          previous_cursor--;
-        }
-        size_t next_cursor = cursor + 1;
-        while (next_cursor < xbt_dynar_length(list)) {
-          if (_sg_mc_liveness) {
-            ref_test = (mc_visited_pair_t) xbt_dynar_get_as(list, next_cursor, mc_visited_pair_t);
-            nb_processes_test = ((mc_visited_pair_t) ref_test)->nb_processes;
-            heap_bytes_used_test = ((mc_visited_pair_t) ref_test)->heap_bytes_used;
-          } else {
-            ref_test = (mc_visited_state_t) xbt_dynar_get_as(list, next_cursor, mc_visited_state_t);
-            nb_processes_test = ((mc_visited_state_t) ref_test)->nb_processes;
-            heap_bytes_used_test = ((mc_visited_state_t) ref_test)->heap_bytes_used;
-          }
-          if (nb_processes_test != nb_processes || heap_bytes_used_test != heap_bytes_used)
-            break;
-          *max = next_cursor;
-          next_cursor++;
-        }
-        return -1;
-      }
-    }
+  while (visited_states.size() > (std::size_t) _sg_mc_visited) {
+    XBT_DEBUG("Try to remove visited state (maximum number of stored states reached)");
+    auto min_element = std::min_element(visited_states.begin(), visited_states.end(),
+      [](std::unique_ptr<simgrid::mc::VisitedState>& a, std::unique_ptr<simgrid::mc::VisitedState>& b) {
+        return a->num < b->num;
+      });
+    xbt_assert(min_element != visited_states.end());
+    // and drop it:
+    visited_states.erase(min_element);
+    XBT_DEBUG("Remove visited state (maximum number of stored states reached)");
   }
-  return cursor;
-}
-
-static
-void replace_state(
-  mc_visited_state_t state_test, mc_visited_state_t new_state, int cursor)
-{
-  if (state_test->other_num == -1)
-    new_state->other_num = state_test->num;
-  else
-    new_state->other_num = state_test->other_num;
-
-  if (dot_output == NULL)
-    XBT_DEBUG("State %d already visited ! (equal to state %d)",
-      new_state->num, state_test->num);
-  else
-    XBT_DEBUG(
-      "State %d already visited ! (equal to state %d (state %d in dot_output))",
-      new_state->num, state_test->num, new_state->other_num);
-
-  /* Replace the old state with the new one (with a bigger num)
-     (when the max number of visited states is reached,  the oldest
-     one is removed according to its number (= with the min number) */
-  xbt_dynar_remove_at(visited_states, cursor, NULL);
-  xbt_dynar_insert_at(visited_states, cursor, &new_state);
-  XBT_DEBUG("Replace visited state %d with the new visited state %d",
-    state_test->num, new_state->num);
 }
 
-static
-bool some_dommunications_are_not_finished()
+static int snapshot_compare(simgrid::mc::VisitedState* state1, simgrid::mc::VisitedState* state2)
 {
-  for (size_t current_process = 1; current_process < MC_smx_get_maxpid(); current_process++) {
-    xbt_dynar_t pattern = xbt_dynar_get_as(
-      incomplete_communications_pattern, current_process, xbt_dynar_t);
-    if (!xbt_dynar_is_empty(pattern)) {
-      XBT_DEBUG("Some communications are not finished, cannot stop the exploration ! State not visited.");
-      return true;
-    }
-  }
-  return false;
+  simgrid::mc::Snapshot* s1 = state1->system_state.get();
+  simgrid::mc::Snapshot* s2 = state2->system_state.get();
+  int num1 = state1->num;
+  int num2 = state2->num;
+  return snapshot_compare(num1, s1, num2, s2);
 }
 
 /**
  * \brief Checks whether a given state has already been visited by the algorithm.
  */
-
-mc_visited_state_t is_visited_state(mc_state_t graph_state)
+std::unique_ptr<simgrid::mc::VisitedState> is_visited_state(simgrid::mc::State* graph_state, bool compare_snpashots)
 {
 
-  if (_sg_mc_visited == 0)
-    return NULL;
 
-  /* If comm determinism verification, we cannot stop the exploration if some 
-     communications are not finished (at least, data are transfered). These communications 
-     are incomplete and they cannot be analyzed and compared with the initial pattern. */
-  int partial_comm = (_sg_mc_comms_determinism || _sg_mc_send_determinism) &&
-    some_dommunications_are_not_finished();
-
-  mc_visited_state_t new_state = visited_state_new();
+  std::unique_ptr<simgrid::mc::VisitedState> new_state =
+    std::unique_ptr<simgrid::mc::VisitedState>(new VisitedState());
   graph_state->system_state = new_state->system_state;
   graph_state->in_visited_states = 1;
-  XBT_DEBUG("Snapshot %p of visited state %d (exploration stack state %d)", new_state->system_state, new_state->num, graph_state->num);
-
-  if (xbt_dynar_is_empty(visited_states)) {
+  XBT_DEBUG("Snapshot %p of visited state %d (exploration stack state %d)",
+    new_state->system_state.get(), new_state->num, graph_state->num);
 
-    xbt_dynar_push(visited_states, &new_state);
-    return NULL;
+  auto range = std::equal_range(visited_states.begin(), visited_states.end(),
+    new_state.get(), simgrid::mc::DerefAndCompareByNbProcessesAndUsedHeap());
 
-  } else {
+      if (compare_snpashots) {
 
-    int min = -1, max = -1, index;
-
-    index = get_search_interval(visited_states, new_state, &min, &max);
-
-    if (min != -1 && max != -1) {
-
-      // Parallell implementation
-      /*res = xbt_parmap_mc_apply(parmap, snapshot_compare, xbt_dynar_get_ptr(visited_states, min), (max-min)+1, new_state);
-         if(res != -1){
-         mc_visited_state_t state_test = (mc_visited_state_t)xbt_dynar_get_as(visited_states, (min+res)-1, mc_visited_state_t);
-         if(state_test->other_num == -1)
-         new_state->other_num = state_test->num;
-         else
-         new_state->other_num = state_test->other_num;
-         if(dot_output == NULL)
-         XBT_DEBUG("State %d already visited ! (equal to state %d)", new_state->num, state_test->num);
-         else
-         XBT_DEBUG("State %d already visited ! (equal to state %d (state %d in dot_output))", new_state->num, state_test->num, new_state->other_num);
-         xbt_dynar_remove_at(visited_states, (min + res) - 1, NULL);
-         xbt_dynar_insert_at(visited_states, (min+res) - 1, &new_state);
-         return new_state->other_num;
-         } */
-
-      if (_sg_mc_safety || (!partial_comm
-        && initial_global_state->initial_communications_pattern_done)) {
-
-        int cursor = min;
-        while (cursor <= max) {
-          mc_visited_state_t state_test = (mc_visited_state_t) xbt_dynar_get_as(visited_states, cursor, mc_visited_state_t);
-          if (snapshot_compare(state_test, new_state) == 0) {
+        for (auto i = range.first; i != range.second; ++i) {
+          auto& visited_state = *i;
+          if (snapshot_compare(visited_state.get(), new_state.get()) == 0) {
             // The state has been visited:
 
-            replace_state(state_test, new_state, cursor);
-            return state_test;
+            std::unique_ptr<simgrid::mc::VisitedState> old_state =
+              std::move(visited_state);
+
+            if (old_state->other_num == -1)
+              new_state->other_num = old_state->num;
+            else
+              new_state->other_num = old_state->other_num;
+
+            if (dot_output == nullptr)
+              XBT_DEBUG("State %d already visited ! (equal to state %d)",
+                new_state->num, old_state->num);
+            else
+              XBT_DEBUG(
+                "State %d already visited ! (equal to state %d (state %d in dot_output))",
+                new_state->num, old_state->num, new_state->other_num);
+
+            /* Replace the old state with the new one (with a bigger num)
+               (when the max number of visited states is reached,  the oldest
+               one is removed according to its number (= with the min number) */
+            XBT_DEBUG("Replace visited state %d with the new visited state %d",
+              old_state->num, new_state->num);
+
+            visited_state = std::move(new_state);
+            return std::move(old_state);
           }
-          cursor++;
         }
       }
-      
-      xbt_dynar_insert_at(visited_states, min, &new_state);
-      XBT_DEBUG("Insert new visited state %d (total : %lu)", new_state->num, xbt_dynar_length(visited_states));
-      
-    } else {
-
-      // The state has not been visited: insert the state in the dynamic array.
-      mc_visited_state_t state_test = (mc_visited_state_t) xbt_dynar_get_as(visited_states, index, mc_visited_state_t);
-      if (state_test->nb_processes < new_state->nb_processes) {
-        xbt_dynar_insert_at(visited_states, index + 1, &new_state);
-      } else {
-        if (state_test->heap_bytes_used < new_state->heap_bytes_used)
-          xbt_dynar_insert_at(visited_states, index + 1, &new_state);
-        else
-          xbt_dynar_insert_at(visited_states, index, &new_state);
-      }
-
-       XBT_DEBUG("Insert new visited state %d (total : %lu)", new_state->num, xbt_dynar_length(visited_states));
-
-    }
-
-    // We have reached the maximum number of stored states;
-    if ((ssize_t) xbt_dynar_length(visited_states) > _sg_mc_visited) {
-
-      XBT_DEBUG("Try to remove visited state (maximum number of stored states reached)");
 
-      // Find the (index of the) older state (with the smallest num):
-      int min2 = mc_stats->expanded_states;
-      unsigned int cursor2 = 0;
-      unsigned int index2 = 0;
-
-      mc_visited_state_t state_test;
-      xbt_dynar_foreach(visited_states, cursor2, state_test){
-        if (!MC_important_snapshot(state_test->system_state) && state_test->num < min2) {
-          index2 = cursor2;
-          min2 = state_test->num;
-        }
-      }
-
-      // and drop it:
-      xbt_dynar_remove_at(visited_states, index2, NULL);
-      XBT_DEBUG("Remove visited state (maximum number of stored states reached)");
-    }
-
-    return NULL;
-  }
-}
-
-/**
- * \brief Checks whether a given pair has already been visited by the algorithm.
- */
-int is_visited_pair(mc_visited_pair_t visited_pair, mc_pair_t pair) {
-
-  if (_sg_mc_visited == 0)
-    return -1;
-
-  mc_visited_pair_t new_visited_pair = NULL;
-
-  if (visited_pair == NULL) {
-    new_visited_pair = MC_visited_pair_new(pair->num, pair->automaton_state, pair->atomic_propositions, pair->graph_state);
-  } else {
-    new_visited_pair = visited_pair;
-  }
-
-  if (xbt_dynar_is_empty(visited_pairs)) {
-
-    xbt_dynar_push(visited_pairs, &new_visited_pair);
-
-  } else {
-
-    int min = -1, max = -1, index;
-    //int res;
-    mc_visited_pair_t pair_test;
-    int cursor;
-
-    index = get_search_interval(visited_pairs, new_visited_pair, &min, &max);
-
-    if (min != -1 && max != -1) {       // Visited pair with same number of processes and same heap bytes used exists
-      /*res = xbt_parmap_mc_apply(parmap, snapshot_compare, xbt_dynar_get_ptr(visited_pairs, min), (max-min)+1, pair);
-         if(res != -1){
-         pair_test = (mc_pair_t)xbt_dynar_get_as(visited_pairs, (min+res)-1, mc_pair_t);
-         if(pair_test->other_num == -1)
-         pair->other_num = pair_test->num;
-         else
-         pair->other_num = pair_test->other_num;
-         if(dot_output == NULL)
-         XBT_DEBUG("Pair %d already visited ! (equal to pair %d)", pair->num, pair_test->num);
-         else
-         XBT_DEBUG("Pair %d already visited ! (equal to pair %d (pair %d in dot_output))", pair->num, pair_test->num, pair->other_num);
-         xbt_dynar_remove_at(visited_pairs, (min + res) - 1, NULL);
-         xbt_dynar_insert_at(visited_pairs, (min+res) - 1, &pair);
-         pair_test->visited_removed = 1;
-         if(pair_test->stack_removed && pair_test->visited_removed){
-         if((pair_test->automaton_state->type == 1) || (pair_test->automaton_state->type == 2)){
-         if(pair_test->acceptance_removed){
-         MC_pair_delete(pair_test);
-         }
-         }else{
-         MC_pair_delete(pair_test);
-         }
-         }
-         return pair->other_num;
-         } */
-      cursor = min;
-      while (cursor <= max) {
-        pair_test = (mc_visited_pair_t) xbt_dynar_get_as(visited_pairs, cursor, mc_visited_pair_t);
-        if (xbt_automaton_state_compare(pair_test->automaton_state, new_visited_pair->automaton_state) == 0) {
-          if (xbt_automaton_propositional_symbols_compare_value(pair_test->atomic_propositions, new_visited_pair->atomic_propositions) == 0) {
-            if (snapshot_compare(pair_test, new_visited_pair) == 0) {
-              if (pair_test->other_num == -1)
-                new_visited_pair->other_num = pair_test->num;
-              else
-                new_visited_pair->other_num = pair_test->other_num;
-              if (dot_output == NULL)
-                XBT_DEBUG("Pair %d already visited ! (equal to pair %d)", new_visited_pair->num, pair_test->num);
-              else
-                XBT_DEBUG("Pair %d already visited ! (equal to pair %d (pair %d in dot_output))", new_visited_pair->num, pair_test->num, new_visited_pair->other_num);
-              xbt_dynar_remove_at(visited_pairs, cursor, &pair_test);
-              xbt_dynar_insert_at(visited_pairs, cursor, &new_visited_pair);
-              pair_test->visited_removed = 1;
-              if (pair_test->acceptance_pair) {
-                if (pair_test->acceptance_removed == 1)
-                  MC_visited_pair_delete(pair_test);
-              } else {
-                MC_visited_pair_delete(pair_test);
-              }
-              return new_visited_pair->other_num;
-            }
-          }
-        }
-        cursor++;
-      }
-      xbt_dynar_insert_at(visited_pairs, min, &new_visited_pair);
-    } else {
-      pair_test = (mc_visited_pair_t) xbt_dynar_get_as(visited_pairs, index, mc_visited_pair_t);
-      if (pair_test->nb_processes < new_visited_pair->nb_processes) {
-        xbt_dynar_insert_at(visited_pairs, index + 1, &new_visited_pair);
-      } else {
-        if (pair_test->heap_bytes_used < new_visited_pair->heap_bytes_used)
-          xbt_dynar_insert_at(visited_pairs, index + 1, &new_visited_pair);
-        else
-          xbt_dynar_insert_at(visited_pairs, index, &new_visited_pair);
-      }
-    }
-
-    if ((ssize_t) xbt_dynar_length(visited_pairs) > _sg_mc_visited) {
-      int min2 = mc_stats->expanded_pairs;
-      unsigned int cursor2 = 0;
-      unsigned int index2 = 0;
-      xbt_dynar_foreach(visited_pairs, cursor2, pair_test) {
-        if (!MC_important_snapshot(pair_test->graph_state->system_state)
-            && pair_test->num < min2) {
-          index2 = cursor2;
-          min2 = pair_test->num;
-        }
-      }
-      xbt_dynar_remove_at(visited_pairs, index2, &pair_test);
-      pair_test->visited_removed = 1;
-      if (pair_test->acceptance_pair) {
-        if (pair_test->acceptance_removed)
-          MC_visited_pair_delete(pair_test);
-      } else {
-        MC_visited_pair_delete(pair_test);
-      }
-    }
-
-  }
-  return -1;
+  XBT_DEBUG("Insert new visited state %d (total : %lu)", new_state->num, (unsigned long) visited_states.size());
+  visited_states.insert(range.first, std::move(new_state));
+  prune_visited_states();
+  return nullptr;
 }
 
 }
+}
\ No newline at end of file