Temporary interface: Add fsm_determinise_with_config.

include/fsm/fsm.h

@@ -385,6 +385,21 @@ fsm_remove_epsilons(struct fsm *fsm);
 int
 fsm_determinise(struct fsm *fsm);
 
+/* Determinise, with a passed in configuration
+ * and a distinct return value for reaching
+ * the state limit. */
+struct fsm_determinise_config {
+ size_t state_limit; /* 0: no limit */
+};
+enum fsm_determinise_with_config_res {
+ FSM_DETERMINISE_WITH_CONFIG_OK,
+ FSM_DETERMINISE_WITH_CONFIG_STATE_LIMIT_REACHED,
+ FSM_DETERMINISE_WITH_CONFIG_ERRNO,
+};
+enum fsm_determinise_with_config_res
+fsm_determinise_with_config(struct fsm *fsm,
+ const struct fsm_determinise_config *config);
+
 /*
  * Make a DFA complete, as per fsm_iscomplete.
  */

src/libfsm/determinise.c

@@ -17,16 +17,20 @@ dump_labels(FILE *f, const uint64_t labels[4])
  }
 }
 
-int
-fsm_determinise(struct fsm *nfa)
+enum fsm_determinise_with_config_res
+fsm_determinise_with_config(struct fsm *nfa,
+ const struct fsm_determinise_config *config)
 {
- int res = 0;
+ enum fsm_determinise_with_config_res res = FSM_DETERMINISE_WITH_CONFIG_ERRNO;
  struct mappingstack *stack = NULL;
 
  struct interned_state_set_pool *issp = NULL;
  struct map map = { NULL, 0, 0, NULL };
  struct mapping *curr = NULL;
  size_t dfacount = 0;
+ const size_t state_limit = config == NULL
+ ? 0
+ : config->state_limit;
 
  struct analyze_closures_env ac_env = { 0 };
 
@@ -40,7 +44,7 @@ fsm_determinise(struct fsm *nfa)
  */
  if (fsm_has(nfa, fsm_hasepsilons)) {
  if (!fsm_remove_epsilons(nfa)) {
- return 0;
+ return FSM_DETERMINISE_WITH_CONFIG_ERRNO;
  }
  }
 
@@ -52,7 +56,12 @@ fsm_determinise(struct fsm *nfa)
 
  issp = interned_state_set_pool_alloc(nfa->alloc);
  if (issp == NULL) {
- return 0;
+ return FSM_DETERMINISE_WITH_CONFIG_ERRNO;
+ }
+
+ if (state_limit != 0 && fsm_countstates(nfa) > state_limit) {
+ res = FSM_DETERMINISE_WITH_CONFIG_STATE_LIMIT_REACHED;
+ goto cleanup;
  }
 
  {
@@ -74,7 +83,7 @@ fsm_determinise(struct fsm *nfa)
  */
 
  if (!fsm_getstart(nfa, &start)) {
- res = 1;
+ res = FSM_DETERMINISE_WITH_CONFIG_OK;
  goto cleanup;
  }
 
@@ -150,6 +159,11 @@ fsm_determinise(struct fsm *nfa)
  assert(m->dfastate < dfacount);
  } else {
  /* not found -- add a new one and push it to the stack for processing */
+
+ if (state_limit != 0 && dfacount > state_limit) {
+ res = FSM_DETERMINISE_WITH_CONFIG_STATE_LIMIT_REACHED;
+ goto cleanup;
+ }
  if (!map_add(&map, dfacount, iss, &m)) {
  goto cleanup;
  }
@@ -260,7 +274,7 @@ fsm_determinise(struct fsm *nfa)
  assert(fsm_all(nfa, fsm_isdfa));
 #endif
 
- res = 1;
+ res = FSM_DETERMINISE_WITH_CONFIG_OK;
 
 cleanup:
  map_free(&map);
@@ -311,6 +325,21 @@ fsm_determinise(struct fsm *nfa)
  return res;
 }
 
+int
+fsm_determinise(struct fsm *nfa)
+{
+ enum fsm_determinise_with_config_res res = fsm_determinise_with_config(nfa, NULL);
+ switch (res) {
+ case FSM_DETERMINISE_WITH_CONFIG_OK:
+ return 1;
+ case FSM_DETERMINISE_WITH_CONFIG_STATE_LIMIT_REACHED:
+ /* unreachable */
+ return 0;
+ case FSM_DETERMINISE_WITH_CONFIG_ERRNO:
+ return 0;
+ }
+}
+
 /* Add DFA_state to the list for NFA_state. */
 static int
 add_reverse_mapping(const struct fsm_alloc *alloc,

src/libfsm/libfsm.syms

@@ -101,6 +101,7 @@ fsm_countstates
 fsm_trim
 fsm_reverse
 fsm_determinise
+fsm_determinise_with_config
 fsm_remove_epsilons
 fsm_complete
 fsm_minimise