Use hash.h for the state hash table.

* src/LR0.c (STATE_HASH_SIZE, state_hash): Remove.
(allocate_storage): Use state_hash_new.
(free_storage): Use state_hash_free.
(new_state, get_state): Adjust.
* src/lalr.h, src/lalr.c (states): Move to...
* src/states.h (state_t): Remove the `link' member, no longer
used.
* src/states.h, src/states.c: here.
(state_hash_new, state_hash_free, state_hash_lookup)
(state_hash_insert, states_free): New.
* src/states.c (state_table, state_compare, state_hash): New.
* src/output.c (output_actions): Do not free states now, since we
still need to know the final_state number in `prepare', called
afterwards.  Do it...
* src/main.c (main): here: call states_free after `output'.

ChangeLog

@@ -1,3 +1,24 @@
+2002-06-30  Akim Demaille  <akim@epita.fr>
+
+	Use hash.h for the state hash table.
+
+	* src/LR0.c (STATE_HASH_SIZE, state_hash): Remove.
+	(allocate_storage): Use state_hash_new.
+	(free_storage): Use state_hash_free.
+	(new_state, get_state): Adjust.
+	* src/lalr.h, src/lalr.c (states): Move to...
+	* src/states.h (state_t): Remove the `link' member, no longer
+	used.
+	* src/states.h, src/states.c: here.
+	(state_hash_new, state_hash_free, state_hash_lookup)
+	(state_hash_insert, states_free): New.
+	* src/states.c (state_table, state_compare, state_hash): New.
+	* src/output.c (output_actions): Do not free states now, since we
+	still need to know the final_state number in `prepare', called
+	afterwards.  Do it...
+	* src/main.c (main): here: call states_free after `output'.
+
+	
 2002-06-30  Akim Demaille  <akim@epita.fr>
 
 	* src/state.h, src/state.c (state_new): New, extracted from...

src/LR0.c

@@ -52,11 +52,6 @@ static item_number_t **kernel_base = NULL;
 static int *kernel_size = NULL;
 static item_number_t *kernel_items = NULL;
 
-/* hash table for states, to recognize equivalent ones.  */
-
-#define	STATE_HASH_SIZE	1009
-static state_t **state_hash = NULL;
-
 
 static void
 allocate_itemsets (void)
@@ -107,7 +102,7 @@ allocate_storage (void)
 
   shiftset = XCALLOC (state_number_t, nsyms);
   redset = XCALLOC (short, nrules + 1);
-  state_hash = XCALLOC (state_t *, STATE_HASH_SIZE);
+  state_hash_new ();
   shift_symbol = XCALLOC (symbol_number_t, nsyms);
 }
 
@@ -121,7 +116,7 @@ free_storage (void)
   free (kernel_base);
   free (kernel_size);
   XFREE (kernel_items);
-  free (state_hash);
+  state_hash_free ();
 }
 
 
@@ -185,6 +180,7 @@ new_state (symbol_number_t symbol, size_t core_size, item_number_t *core)
 	     nstates, symbol, symbol_tag_get (symbols[symbol]));
 
   res = state_new (symbol, core_size, core);
+  state_hash_insert (res);
 
   /* If this is the eoftoken, and this is not the initial state, then
      this is the final state.  */
@@ -210,8 +206,6 @@ new_state (symbol_number_t symbol, size_t core_size, item_number_t *core)
 static state_number_t
 get_state (symbol_number_t symbol, size_t core_size, item_number_t *core)
 {
-  int key;
-  size_t i;
   state_t *sp;
 
   if (trace_flag)
@@ -219,45 +213,9 @@ get_state (symbol_number_t symbol, size_t core_size, item_number_t *core)
 	     this_state->number, symbol,
 	     symbol_tag_get (symbols[symbol]));
 
-  /* Add up the target state's active item numbers to get a hash key.
-     */
-  key = 0;
-  for (i = 0; i < core_size; ++i)
-    key += core[i];
-  key = key % STATE_HASH_SIZE;
-  sp = state_hash[key];
-
-  if (sp)
-    {
-      int found = 0;
-      while (!found)
-	{
-	  if (sp->nitems == core_size)
-	    {
-	      found = 1;
-	      for (i = 0; i < core_size; ++i)
-		if (core[i] != sp->items[i])
-		  found = 0;
-	    }
-
-	  if (!found)
-	    {
-	      if (sp->link)
-		{
-		  sp = sp->link;
-		}
-	      else		/* bucket exhausted and no match */
-		{
-		  sp = sp->link = new_state (symbol, core_size, core);
-		  found = 1;
-		}
-	    }
-	}
-    }
-  else				/* bucket is empty */
-    {
-      state_hash[key] = sp = new_state (symbol, core_size, core);
-    }
+  sp = state_hash_lookup (core_size, core);
+  if (!sp)
+    sp = new_state (symbol, core_size, core);
 
   if (trace_flag)
     fprintf (stderr, "Exiting get_state => %d\n", sp->number);
@@ -386,6 +344,7 @@ set_states (void)
     }
 }
 
+
 /*-------------------------------------------------------------------.
 | Compute the nondeterministic finite state machine (see state.h for |
 | details) from the grammar.                                         |

src/lalr.c

@@ -39,9 +39,6 @@
 #include "derives.h"
 #include "getargs.h"
 
-/* All the decorated states, indexed by the state number.  */
-state_t **states = NULL;
-
 rule_t **LArule = NULL;
 bitsetv LA = NULL;
 size_t nLA;

src/lalr.h

@@ -71,7 +71,4 @@ extern rule_t **LArule;
 extern bitsetv LA;
 
 
-/* All the states, indexed by the state number.  */
-extern state_t **states;
-
 #endif /* !LALR_H_ */

src/main.c

@@ -105,6 +105,7 @@ main (int argc, char *argv[])
   /* Output the tables and the parser to ftable.  In file output.  */
   output ();
 
+  states_free ();
   reduce_free ();
   conflicts_free ();
   free_nullable ();

src/output.c

@@ -1132,8 +1132,6 @@ output_check (void)
 static void
 output_actions (void)
 {
-  state_number_t i;
-
   /* That's a poor way to make sure the sizes are properly corelated,
      in particular the signedness is not taking into account, but it's
      not useless.  */
@@ -1165,15 +1163,6 @@ output_actions (void)
   output_conflicts ();
 
   output_check ();
-
-  for (i = 0; i < nstates; ++i)
-    {
-      free (states[i]->shifts);
-      XFREE (states[i]->reductions);
-      free (states[i]->errs);
-      free (states[i]);
-    }
-  XFREE (states);
 }
 
 

src/state.c

@@ -20,6 +20,7 @@
 
 
 #include "system.h"
+#include "hash.h"
 #include "complain.h"
 #include "gram.h"
 #include "state.h"
@@ -30,9 +31,9 @@
 			`-------------------*/
 
 
-/*---------------------------------.
-| Create a new array of N shitfs.  |
-`---------------------------------*/
+/*---------------------------------------.
+| Create a new array of N shifts/gotos.  |
+`---------------------------------------*/
 
 #define SHIFTS_ALLOC(Nshifts)						\
   (shifts *) xcalloc ((unsigned) (sizeof (shifts) 			\
@@ -116,6 +117,10 @@ state_number_t nstates = 0;
    accessing symbol: EOF.  */
 state_t *final_state = NULL;
 
+#define STATE_ALLOC(Nitems)						\
+  (state_t *) xcalloc ((unsigned) (sizeof (state_t) 			\
+                                  + (Nitems - 1) * sizeof (item_number_t)), 1)
+
 /*------------------------------------------------------------.
 | Create a new state with ACCESSING_SYMBOL, for those items.  |
 `------------------------------------------------------------*/
@@ -129,10 +134,6 @@ state_new (symbol_number_t accessing_symbol,
   if (nstates >= STATE_NUMBER_MAX)
     fatal (_("too many states (max %d)"), STATE_NUMBER_MAX);
 
-#define STATE_ALLOC(Nitems)						\
-  (state_t *) xcalloc ((unsigned) (sizeof (state_t) 			\
-                                  + (Nitems - 1) * sizeof (item_number_t)), 1)
-
   res = STATE_ALLOC (core_size);
   res->accessing_symbol = accessing_symbol;
   res->number = nstates;
@@ -177,3 +178,119 @@ state_rule_lookaheads_print (state_t *state, rule_t *rule, FILE *out)
       fprintf (out, "]");
     }
 }
+
+
+/*----------------------.
+| A state hash table.  |
+`----------------------*/
+
+/* Initial capacity of states hash table.  */
+#define HT_INITIAL_CAPACITY 257
+
+static struct hash_table *state_table = NULL;
+
+/* Two states are equal if they have the same core items.  */
+static bool
+state_compare (const state_t *s1, const state_t *s2)
+{
+  int i;
+
+  if (s1->nitems != s2->nitems)
+    return FALSE;
+
+  for (i = 0; i < s1->nitems; ++i)
+    if (s1->items[i] != s2->items[i])
+      return FALSE;
+
+  return TRUE;
+}
+
+static unsigned int
+state_hash (const state_t *state, unsigned int tablesize)
+{
+  /* Add up the state's item numbers to get a hash key.  */
+  int key = 0;
+  int i;
+  for (i = 0; i < state->nitems; ++i)
+    key += state->items[i];
+  return key % tablesize;
+}
+
+
+/*-------------------------------.
+| Create the states hash table.  |
+`-------------------------------*/
+
+void
+state_hash_new (void)
+{
+  state_table = hash_initialize (HT_INITIAL_CAPACITY,
+				 NULL,
+				 (Hash_hasher) state_hash,
+				 (Hash_comparator) state_compare,
+				 (Hash_data_freer) NULL);
+}
+
+
+/*---------------------------------------------.
+| Free the states hash table, not the states.  |
+`---------------------------------------------*/
+
+void
+state_hash_free (void)
+{
+  hash_free (state_table);
+}
+
+
+/*---------------------------------------.
+| Insert STATE in the state hash table.  |
+`---------------------------------------*/
+
+void
+state_hash_insert (state_t *state)
+{
+  hash_insert (state_table, state);
+}
+
+
+/*------------------------------------------------------------------.
+| Find the state associated to the CORE, and return it.  If it does |
+| not exist yet, return NULL.                                       |
+`------------------------------------------------------------------*/
+
+state_t *
+state_hash_lookup (size_t core_size, item_number_t *core)
+{
+  state_t *probe = STATE_ALLOC (core_size);
+  state_t *entry;
+
+  probe->nitems = core_size;
+  memcpy (probe->items, core, core_size * sizeof (core[0]));
+  entry = hash_lookup (state_table, probe);
+  free (probe);
+  return entry;
+}
+
+/* All the decorated states, indexed by the state number.  */
+state_t **states = NULL;
+
+
+/*----------------------.
+| Free all the states.  |
+`----------------------*/
+
+void
+states_free (void)
+{
+  state_number_t i;
+
+  for (i = 0; i < nstates; ++i)
+    {
+      free (states[i]->shifts);
+      XFREE (states[i]->reductions);
+      free (states[i]->errs);
+      free (states[i]);
+    }
+  XFREE (states);
+}

src/state.h

@@ -44,10 +44,6 @@
    Each core contains a vector of NITEMS items which are the indices
    in the RITEMS vector of the items that are selected in this state.
 
-   The link field is used for chaining symbols that hash states by
-   their itemsets.  This is for recognizing equivalent states and
-   combining them when the states are generated.
-
    The two types of transitions are shifts (push the lookahead token
    and read another) and reductions (combine the last n things on the
    stack via a rule, replace them with the symbol that the rule
@@ -180,7 +176,6 @@ reductions *reductions_new PARAMS ((int n));
 typedef struct state_s
 {
   struct state_s *next;
-  struct state_s *link;
 
   state_number_t number;
   symbol_number_t accessing_symbol;
@@ -220,4 +215,20 @@ state_t *state_new PARAMS ((symbol_number_t accessing_symbol,
 void state_rule_lookaheads_print PARAMS ((state_t *state, rule_t *rule,
 					  FILE *out));
 
+/* Create/destroy the states hash table.  */
+void state_hash_new PARAMS ((void));
+void state_hash_free PARAMS ((void));
+
+/* Find the state associated to the CORE, and return it.  If it does
+   not exist yet, return NULL.  */
+state_t *state_hash_lookup PARAMS ((size_t core_size, item_number_t *core));
+
+/* Insert STATE in the state hash table.  */
+void state_hash_insert PARAMS ((state_t *state));
+
+/* All the states, indexed by the state number.  */
+extern state_t **states;
+
+/* Free all the states.  */
+void states_free PARAMS ((void));
 #endif /* !STATE_H_ */