doc: merge HACKING and README-hacking.

[bison.git] / lib / ebitset.c

diff --git a/lib/ebitset.c b/lib/ebitset.c
index 0a6cbd41ccb288c8b5d0ce0e15ca5479692df557..cdbbe2de95771c7d149229178cba89e317b94bd1 100644 (file)
--- a/lib/ebitset.c
+++ b/lib/ebitset.c
@@ -1,43 +1,32 @@
-/* Functions to support efficient bitsets.
-   Copyright (C) 2002 Free Software Foundation, Inc.
+/* Functions to support expandable bitsets.
+   Copyright (C) 2002, 2003, 2004, 2005, 2006 Free Software Foundation, Inc.

    Contributed by Michael Hayes (m.hayes@elec.canterbury.ac.nz).
 
    Contributed by Michael Hayes (m.hayes@elec.canterbury.ac.nz).
 

-This program 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 2 of the License, or
-(at your option) any later version.
+   This program 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 of the License, or
+   (at your option) any later version.

 
 

-This program 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.
+   This program 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 this program; if not, write to the Free Software
-Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */

 
 

-#ifdef HAVE_CONFIG_H
-#include "config.h"
-#endif
+#include <config.h>
+
+#include "ebitset.h"

 
 

-#include "bitset.h"

 #include "obstack.h"
 #include <stdlib.h>
 #include "obstack.h"
 #include <stdlib.h>

+#include <string.h>

 
 

-# if WITH_DMALLOC
-#  define DMALLOC_FUNC_CHECK
-#  include <dmalloc.h>
-# endif /* WITH_DMALLOC */
-
-/* This file implements linked-list bitsets.  These bitsets can be of
+/* This file implements expandable bitsets.  These bitsets can be of

    arbitrary length and are more efficient than arrays of bits for
    large sparse sets.
 
    arbitrary length and are more efficient than arrays of bits for
    large sparse sets.
 

-   Usually if all the bits in an element are zero we remove the element
-   from the list.  However, a side effect of the bit caching is that we
-   do not always notice when an element becomes zero.  Hence the
-   ebitset_weed function which removes zero elements.
-

    Empty elements are represented by a NULL pointer in the table of
    element pointers.  An alternative is to point to a special zero
    element.  Similarly, we could represent an all 1's element with
    Empty elements are represented by a NULL pointer in the table of
    element pointers.  An alternative is to point to a special zero
    element.  Similarly, we could represent an all 1's element with


@@ -49,113 +38,145 @@ Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
    be zero.
 
    The bitset cache can be disabled either by setting cindex to
    be zero.
 
    The bitset cache can be disabled either by setting cindex to

-   some large number or by setting csize to 0.  Here
+   BITSET_WINDEX_MAX or by setting csize to 0.  Here

    we use the former approach since cindex needs to be updated whenever
    cdata is changed.
 */
 
    we use the former approach since cindex needs to be updated whenever
    cdata is changed.
 */
 

+
+/* Number of words to use for each element.  */
+#define EBITSET_ELT_WORDS 2
+
+/* Number of bits stored in each element.  */
+#define EBITSET_ELT_BITS \
+  ((unsigned int) (EBITSET_ELT_WORDS * BITSET_WORD_BITS))
+
+/* Ebitset element.  We use an array of bits.  */
+typedef struct ebitset_elt_struct
+{
+  union
+  {
+    bitset_word words[EBITSET_ELT_WORDS];      /* Bits that are set.  */
+    struct ebitset_elt_struct *next;
+  }
+  u;
+}
+ebitset_elt;
+
+
+typedef ebitset_elt *ebitset_elts;
+
+

 /* Number of elements to initially allocate.  */
 /* Number of elements to initially allocate.  */

+

 #ifndef EBITSET_INITIAL_SIZE
 #define EBITSET_INITIAL_SIZE 2
 #endif
 
 #ifndef EBITSET_INITIAL_SIZE
 #define EBITSET_INITIAL_SIZE 2
 #endif
 

-/* Minimum number of elements to grow table.  */
-#ifndef EBITSET_GROW_SIZE
-#define EBITSET_GROW_SIZE 4
-#endif
-

 
 

-enum ebitset_find_mode {EBITSET_FIND, EBITSET_CREATE, EBITSET_SUBST};
+enum ebitset_find_mode
+  { EBITSET_FIND, EBITSET_CREATE, EBITSET_SUBST };

 
 static ebitset_elt ebitset_zero_elts[1]; /* Elements of all zero bits.  */
 
 /* Obstack to allocate bitset elements from.  */
 static struct obstack ebitset_obstack;
 
 static ebitset_elt ebitset_zero_elts[1]; /* Elements of all zero bits.  */
 
 /* Obstack to allocate bitset elements from.  */
 static struct obstack ebitset_obstack;

-static int ebitset_obstack_init = 0;
-static ebitset_elt *ebitset_free_list; /* Free list of bitset elements.  */
-
-static void ebitset_elts_grow PARAMS ((bitset, unsigned int));
-static ebitset_elt *ebitset_elt_alloc PARAMS ((void));
-static ebitset_elt *ebitset_elt_calloc PARAMS ((void));
-static void ebitset_elt_add PARAMS ((bitset, ebitset_elt *, unsigned int));
-static void ebitset_elt_remove PARAMS ((bitset, unsigned int));
-static void ebitset_elt_free PARAMS ((ebitset_elt *));
-static ebitset_elt *ebitset_elt_find PARAMS ((bitset, bitset_windex,
-                                             enum ebitset_find_mode));
-static ebitset_elt *ebitset_elt_last PARAMS ((bitset));
-static int ebitset_elt_zero_p PARAMS ((ebitset_elt *));
-
-static int ebitset_weed PARAMS ((bitset));
-static void ebitset_zero PARAMS((bitset));
-static int ebitset_equal_p PARAMS((bitset, bitset));
-static void ebitset_copy PARAMS((bitset, bitset));
-static int ebitset_copy_compare PARAMS((bitset, bitset));
-static void ebitset_set PARAMS((bitset, bitset_bindex));
-static void ebitset_reset PARAMS((bitset, bitset_bindex));
-static int ebitset_test PARAMS((bitset, bitset_bindex));
-static int ebitset_size PARAMS((bitset));
-static int ebitset_op1 PARAMS((bitset, enum bitset_ops));
-static int ebitset_op2 PARAMS((bitset, bitset, enum bitset_ops));
-static int ebitset_op3 PARAMS((bitset, bitset, bitset, enum bitset_ops));
-static int ebitset_op4 PARAMS((bitset, bitset, bitset, bitset,
-                              enum bitset_ops));
-static int ebitset_list PARAMS((bitset, bitset_bindex *, bitset_bindex,
-                               bitset_bindex *));
-static int ebitset_reverse_list PARAMS((bitset, bitset_bindex *, bitset_bindex,
-                                       bitset_bindex *));
-static void ebitset_free PARAMS((bitset));
-
-
-#define EBITSET_ELTS(BSET) ((BSET)->u.e.elts)
-#define EBITSET_SIZE(BSET) ((BSET)->u.e.size)
+static bool ebitset_obstack_init = false;
+static ebitset_elt *ebitset_free_list; /* Free list of bitset elements.  */
+
+#define EBITSET_N_ELTS(N) (((N) + EBITSET_ELT_BITS - 1) / EBITSET_ELT_BITS)
+#define EBITSET_ELTS(BSET) ((BSET)->e.elts)
+#define EBITSET_SIZE(BSET) EBITSET_N_ELTS (BITSET_NBITS_ (BSET))
+#define EBITSET_ASIZE(BSET) ((BSET)->e.size)

 
 #define EBITSET_NEXT(ELT) ((ELT)->u.next)
 #define EBITSET_WORDS(ELT) ((ELT)->u.words)
 
 /* Disable bitset cache and mark BSET as being zero.  */
 
 #define EBITSET_NEXT(ELT) ((ELT)->u.next)
 #define EBITSET_WORDS(ELT) ((ELT)->u.words)
 
 /* Disable bitset cache and mark BSET as being zero.  */

-#define EBITSET_ZERO_SET(BSET) ((BSET)->cindex = BITSET_INDEX_MAX, \
-        (BSET)->cdata = 0)
+#define EBITSET_ZERO_SET(BSET) ((BSET)->b.cindex = BITSET_WINDEX_MAX, \
+       (BSET)->b.cdata = 0)

 
 

-#define EBITSET_CACHE_DISABLE(BSET)  ((BSET)->cindex = BITSET_INDEX_MAX)
+#define EBITSET_CACHE_DISABLE(BSET)  ((BSET)->b.cindex = BITSET_WINDEX_MAX)

 
 /* Disable bitset cache and mark BSET as being possibly non-zero.  */
 #define EBITSET_NONZERO_SET(BSET) \
 
 /* Disable bitset cache and mark BSET as being possibly non-zero.  */
 #define EBITSET_NONZERO_SET(BSET) \

- (EBITSET_CACHE_DISABLE (BSET), (BSET)->cdata = (bitset_word *)~0)
+ (EBITSET_CACHE_DISABLE (BSET), (BSET)->b.cdata = (bitset_word *)~0)

 
 /* A conservative estimate of whether the bitset is zero.
    This is non-zero only if we know for sure that the bitset is zero.  */
 
 /* A conservative estimate of whether the bitset is zero.
    This is non-zero only if we know for sure that the bitset is zero.  */

-#define EBITSET_ZERO_P(BSET) ((BSET)->cdata == 0)
+#define EBITSET_ZERO_P(BSET) ((BSET)->b.cdata == 0)

 
 /* Enable cache to point to element with table index EINDEX.
    The element must exist.  */
 #define EBITSET_CACHE_SET(BSET, EINDEX) \
 
 /* Enable cache to point to element with table index EINDEX.
    The element must exist.  */
 #define EBITSET_CACHE_SET(BSET, EINDEX) \

- ((BSET)->cindex = (EINDEX) * EBITSET_ELT_WORDS, \
-  (BSET)->cdata = EBITSET_WORDS (EBITSET_ELTS (BSET) [EINDEX]))
+ ((BSET)->b.cindex = (EINDEX) * EBITSET_ELT_WORDS, \
+  (BSET)->b.cdata = EBITSET_WORDS (EBITSET_ELTS (BSET) [EINDEX]))

 
 

+#undef min
+#undef max
+#define min(a, b) ((a) > (b) ? (b) : (a))
+#define max(a, b) ((a) > (b) ? (a) : (b))

 
 

-/* Grow the expandable table for BSET by SIZE elements.  */
-static void
-ebitset_elts_grow (bset, size)
-    bitset bset;
-    unsigned int size;
+static bitset_bindex
+ebitset_resize (bitset src, bitset_bindex n_bits)

 {
 {

-  unsigned int oldsize;
-  unsigned int newsize;
+  bitset_windex oldsize;
+  bitset_windex newsize;
+
+  if (n_bits == BITSET_NBITS_ (src))
+    return n_bits;

 
 

-  oldsize = EBITSET_SIZE (bset);
-  newsize = oldsize + size;
+  oldsize = EBITSET_SIZE (src);
+  newsize = EBITSET_N_ELTS (n_bits);

 
 

-  EBITSET_ELTS (bset) = xrealloc (EBITSET_ELTS (bset),
-                                  newsize * sizeof (ebitset_elt *));
-  EBITSET_SIZE (bset) = newsize;
+  if (oldsize < newsize)
+    {
+      bitset_windex size;
+
+      /* The bitset needs to grow.  If we already have enough memory
+        allocated, then just zero what we need.  */
+      if (newsize > EBITSET_ASIZE (src))
+       {
+         /* We need to allocate more memory.  When oldsize is
+            non-zero this means that we are changing the size, so
+            grow the bitset 25% larger than requested to reduce
+            number of reallocations.  */
+
+         if (oldsize == 0)
+           size = newsize;
+         else
+           size = newsize + newsize / 4;
+
+         EBITSET_ELTS (src)
+           = realloc (EBITSET_ELTS (src), size * sizeof (ebitset_elt *));
+         EBITSET_ASIZE (src) = size;
+       }
+
+      memset (EBITSET_ELTS (src) + oldsize, 0,
+             (newsize - oldsize) * sizeof (ebitset_elt *));
+    }
+  else
+    {
+      /* The bitset needs to shrink.  There's no point deallocating
+        the memory unless it is shrinking by a reasonable amount.  */
+      if ((oldsize - newsize) >= oldsize / 2)
+       {
+         EBITSET_ELTS (src)
+           = realloc (EBITSET_ELTS (src), newsize * sizeof (ebitset_elt *));
+         EBITSET_ASIZE (src) = newsize;
+       }

 
 

-  memset (EBITSET_ELTS (bset) + oldsize, 0, size * sizeof (ebitset_elt *));
+      /* Need to prune any excess bits.  FIXME.  */
+    }
+
+  BITSET_NBITS_ (src) = n_bits;
+  return n_bits;

 }
 
 
 /* Allocate a ebitset element.  The bits are not cleared.  */
 static inline ebitset_elt *
 }
 
 
 /* Allocate a ebitset element.  The bits are not cleared.  */
 static inline ebitset_elt *

-ebitset_elt_alloc ()
+ebitset_elt_alloc (void)

 {
   ebitset_elt *elt;
 
 {
   ebitset_elt *elt;
 


@@ -166,37 +187,38 @@ ebitset_elt_alloc ()
     }
   else
     {
     }
   else
     {

-      /* We can't use gcc_obstack_init to initialize the obstack since
-        print-rtl.c now calls bitset functions, and bitset is linked
-        into the gen* functions.  */

       if (!ebitset_obstack_init)
        {
       if (!ebitset_obstack_init)
        {

-         ebitset_obstack_init = 1;
+         ebitset_obstack_init = true;

 
          /* Let particular systems override the size of a chunk.  */
 
          /* Let particular systems override the size of a chunk.  */

+

 #ifndef OBSTACK_CHUNK_SIZE
 #define OBSTACK_CHUNK_SIZE 0
 #endif
 #ifndef OBSTACK_CHUNK_SIZE
 #define OBSTACK_CHUNK_SIZE 0
 #endif

+

          /* Let them override the alloc and free routines too.  */
          /* Let them override the alloc and free routines too.  */

+

 #ifndef OBSTACK_CHUNK_ALLOC
 #define OBSTACK_CHUNK_ALLOC xmalloc
 #endif
 #ifndef OBSTACK_CHUNK_ALLOC
 #define OBSTACK_CHUNK_ALLOC xmalloc
 #endif

+

 #ifndef OBSTACK_CHUNK_FREE
 #define OBSTACK_CHUNK_FREE free
 #endif
 
 #ifndef OBSTACK_CHUNK_FREE
 #define OBSTACK_CHUNK_FREE free
 #endif
 

-#if !defined(__GNUC__) || (__GNUC__ < 2)
+#if ! defined __GNUC__ || __GNUC__ < 2

 #define __alignof__(type) 0
 #endif
 
          obstack_specify_allocation (&ebitset_obstack, OBSTACK_CHUNK_SIZE,
                                      __alignof__ (ebitset_elt),
 #define __alignof__(type) 0
 #endif
 
          obstack_specify_allocation (&ebitset_obstack, OBSTACK_CHUNK_SIZE,
                                      __alignof__ (ebitset_elt),

-                                     (void *(*) PARAMS ((long))) OBSTACK_CHUNK_ALLOC,
-                                     (void (*) PARAMS ((void *))) OBSTACK_CHUNK_FREE);
+                                     OBSTACK_CHUNK_ALLOC,
+                                     OBSTACK_CHUNK_FREE);

        }
 
       /* Perhaps we should add a number of new elements to the free
        }
 
       /* Perhaps we should add a number of new elements to the free

-         list.  */
+        list.  */

       elt = (ebitset_elt *) obstack_alloc (&ebitset_obstack,
                                           sizeof (ebitset_elt));
     }
       elt = (ebitset_elt *) obstack_alloc (&ebitset_obstack,
                                           sizeof (ebitset_elt));
     }


@@ -205,9 +227,9 @@ ebitset_elt_alloc ()
 }
 
 
 }
 
 

-/* Allocate a ebitset element.  The bits are not cleared.  */
+/* Allocate a ebitset element.  The bits are cleared.  */

 static inline ebitset_elt *
 static inline ebitset_elt *

-ebitset_elt_calloc ()
+ebitset_elt_calloc (void)

 {
   ebitset_elt *elt;
 
 {
   ebitset_elt *elt;
 


@@ -218,8 +240,7 @@ ebitset_elt_calloc ()
 
 
 static inline void
 
 
 static inline void

-ebitset_elt_free (elt)
-     ebitset_elt *elt;
+ebitset_elt_free (ebitset_elt *elt)

 {
   EBITSET_NEXT (elt) = ebitset_free_list;
   ebitset_free_list = elt;
 {
   EBITSET_NEXT (elt) = ebitset_free_list;
   ebitset_free_list = elt;


@@ -228,9 +249,7 @@ ebitset_elt_free (elt)
 
 /* Remove element with index EINDEX from bitset BSET.  */
 static inline void
 
 /* Remove element with index EINDEX from bitset BSET.  */
 static inline void

-ebitset_elt_remove (bset, eindex)
-     bitset bset;
-     unsigned int eindex;
+ebitset_elt_remove (bitset bset, bitset_windex eindex)

 {
   ebitset_elts *elts;
   ebitset_elt *elt;
 {
   ebitset_elts *elts;
   ebitset_elt *elt;


@@ -246,10 +265,7 @@ ebitset_elt_remove (bset, eindex)
 
 /* Add ELT into elts at index EINDEX of bitset BSET.  */
 static inline void
 
 /* Add ELT into elts at index EINDEX of bitset BSET.  */
 static inline void

-ebitset_elt_add (bset, elt, eindex)
-     bitset bset;
-     ebitset_elt *elt;
-     unsigned int eindex;
+ebitset_elt_add (bitset bset, ebitset_elt *elt, bitset_windex eindex)

 {
   ebitset_elts *elts;
 
 {
   ebitset_elts *elts;
 


@@ -259,44 +275,39 @@ ebitset_elt_add (bset, elt, eindex)
 }
 
 
 }
 
 

-/* Return nonzero if all bits in an element are zero.  */
-static inline int
-ebitset_elt_zero_p (elt)
-     ebitset_elt *elt;
+/* Are all bits in an element zero?  */
+static inline bool
+ebitset_elt_zero_p (ebitset_elt *elt)

 {
   int i;
 
   for (i = 0; i < EBITSET_ELT_WORDS; i++)
     if (EBITSET_WORDS (elt)[i])
 {
   int i;
 
   for (i = 0; i < EBITSET_ELT_WORDS; i++)
     if (EBITSET_WORDS (elt)[i])

-      return 0;
+      return false;

 
 

-  return 1;
+  return true;

 }
 
 
 static ebitset_elt *
 }
 
 
 static ebitset_elt *

-ebitset_elt_find (bset, index, mode)
-     bitset bset;
-     bitset_windex index;
-     enum ebitset_find_mode mode;
+ebitset_elt_find (bitset bset, bitset_bindex bindex,
+                 enum ebitset_find_mode mode)

 {
   ebitset_elt *elt;
   bitset_windex size;
 {
   ebitset_elt *elt;
   bitset_windex size;

-  unsigned int eindex;
+  bitset_windex eindex;

   ebitset_elts *elts;
 
   ebitset_elts *elts;
 

-  eindex = index / EBITSET_ELT_WORDS;
+  eindex = bindex / EBITSET_ELT_BITS;

 
   elts = EBITSET_ELTS (bset);
   size = EBITSET_SIZE (bset);
 
   if (eindex < size)
     {
 
   elts = EBITSET_ELTS (bset);
   size = EBITSET_SIZE (bset);
 
   if (eindex < size)
     {

-      ebitset_elt *elt;
-

       if ((elt = elts[eindex]))
        {
       if ((elt = elts[eindex]))
        {

-         if (EBITSET_WORDS (elt) == bset->cdata)
+         if (EBITSET_WORDS (elt) == bset->b.cdata)

            return elt;
 
          EBITSET_CACHE_SET (bset, eindex);
            return elt;
 
          EBITSET_CACHE_SET (bset, eindex);


@@ -308,26 +319,15 @@ ebitset_elt_find (bset, index, mode)
 
   switch (mode)
     {
 
   switch (mode)
     {

+    default:
+      abort ();
+

     case EBITSET_FIND:
       return 0;
 
     case EBITSET_CREATE:
       if (eindex >= size)
     case EBITSET_FIND:
       return 0;
 
     case EBITSET_CREATE:
       if (eindex >= size)

-       {
-         unsigned int extra;
-
-         extra = eindex - size + 1;
-
-         /* We need to expand the table by EXTRA elements.  It may be
-            better with large bitsets to grow the number of
-            elements by some fraction of the current size otherwise
-            we can spend a lot of time slowly increasing the size of the
-            bitset.  */
-         if (extra < EBITSET_GROW_SIZE)
-           extra = EBITSET_GROW_SIZE;
-
-         ebitset_elts_grow (bset, extra);
-       }
+       ebitset_resize (bset, bindex);

 
       /* Create a new element.  */
       elt = ebitset_elt_calloc ();
 
       /* Create a new element.  */
       elt = ebitset_elt_calloc ();


@@ -337,34 +337,17 @@ ebitset_elt_find (bset, index, mode)
 
     case EBITSET_SUBST:
       return &ebitset_zero_elts[0];
 
     case EBITSET_SUBST:
       return &ebitset_zero_elts[0];

-
-    default:
-      abort ();

     }
 }
 
 
     }
 }
 
 

-static inline ebitset_elt *
-ebitset_elt_last (bset)
-     bitset bset;
-{
-  ebitset_elts *elts;
-
-  elts = EBITSET_ELTS (bset);
-
-  /* Assume that have at least one element in elts.  */
-  return elts[EBITSET_SIZE (bset) - 1];
-}
-
-

 /* Weed out the zero elements from the elts.  */
 /* Weed out the zero elements from the elts.  */

-static inline int
-ebitset_weed (bset)
-     bitset bset;
+static inline bitset_windex
+ebitset_weed (bitset bset)

 {
   ebitset_elts *elts;
   bitset_windex j;
 {
   ebitset_elts *elts;
   bitset_windex j;

-  int count;
+  bitset_windex count;

 
   if (EBITSET_ZERO_P (bset))
     return 0;
 
   if (EBITSET_ZERO_P (bset))
     return 0;


@@ -377,7 +360,7 @@ ebitset_weed (bset)
 
       if (elt)
        {
 
       if (elt)
        {

-         if (elt && ebitset_elt_zero_p (elt))
+         if (ebitset_elt_zero_p (elt))

            {
              ebitset_elt_remove (bset, j);
              count++;
            {
              ebitset_elt_remove (bset, j);
              count++;


@@ -397,14 +380,13 @@ ebitset_weed (bset)
   else
     EBITSET_NONZERO_SET (bset);
 
   else
     EBITSET_NONZERO_SET (bset);
 

-  return  count;
+  return count;

 }
 
 
 /* Set all bits in the bitset to zero.  */
 static inline void
 }
 
 
 /* Set all bits in the bitset to zero.  */
 static inline void

-ebitset_zero (bset)
-     bitset bset;
+ebitset_zero (bitset bset)

 {
   ebitset_elts *elts;
   bitset_windex j;
 {
   ebitset_elts *elts;
   bitset_windex j;


@@ -427,23 +409,21 @@ ebitset_zero (bset)
 }
 
 
 }
 
 

-static inline int
-ebitset_equal_p (dst, src)
-     bitset dst;
-     bitset src;
+static inline bool
+ebitset_equal_p (bitset dst, bitset src)

 {
   ebitset_elts *selts;
   ebitset_elts *delts;
   bitset_windex j;
 
   if (src == dst)
 {
   ebitset_elts *selts;
   ebitset_elts *delts;
   bitset_windex j;
 
   if (src == dst)

-    return 1;
+    return true;

 
   ebitset_weed (dst);
   ebitset_weed (src);
 
   if (EBITSET_SIZE (src) != EBITSET_SIZE (dst))
 
   ebitset_weed (dst);
   ebitset_weed (src);
 
   if (EBITSET_SIZE (src) != EBITSET_SIZE (dst))

-    return 0;
+    return false;

 
   selts = EBITSET_ELTS (src);
   delts = EBITSET_ELTS (dst);
 
   selts = EBITSET_ELTS (src);
   delts = EBITSET_ELTS (dst);


@@ -454,24 +434,22 @@ ebitset_equal_p (dst, src)
       ebitset_elt *selt = selts[j];
       ebitset_elt *delt = delts[j];
 
       ebitset_elt *selt = selts[j];
       ebitset_elt *delt = delts[j];
 

-      if (! selt && ! delt)
+      if (!selt && !delt)

        continue;
        continue;

-      if ((selt && ! delt) || (!selt && delt))
-       return 0;
+      if ((selt && !delt) || (!selt && delt))
+       return false;

 
       for (i = 0; i < EBITSET_ELT_WORDS; i++)
        if (EBITSET_WORDS (selt)[i] != EBITSET_WORDS (delt)[i])
 
       for (i = 0; i < EBITSET_ELT_WORDS; i++)
        if (EBITSET_WORDS (selt)[i] != EBITSET_WORDS (delt)[i])

-         return 0;
+         return false;

     }
     }

-  return 1;
+  return true;

 }
 
 
 /* Copy bits from bitset SRC to bitset DST.  */
 static inline void
 }
 
 
 /* Copy bits from bitset SRC to bitset DST.  */
 static inline void

-ebitset_copy (dst, src)
-     bitset dst;
-     bitset src;
+ebitset_copy_ (bitset dst, bitset src)

 {
   ebitset_elts *selts;
   ebitset_elts *delts;
 {
   ebitset_elts *selts;
   ebitset_elts *delts;


@@ -482,8 +460,8 @@ ebitset_copy (dst, src)
 
   ebitset_zero (dst);
 
 
   ebitset_zero (dst);
 

-  if (EBITSET_SIZE (dst) < EBITSET_SIZE (src))
-    ebitset_elts_grow (dst, EBITSET_SIZE (src) - EBITSET_SIZE (dst));
+  if (BITSET_NBITS_ (dst) != BITSET_NBITS_ (src))
+    ebitset_resize (dst, BITSET_NBITS_ (src));

 
   selts = EBITSET_ELTS (src);
   delts = EBITSET_ELTS (dst);
 
   selts = EBITSET_ELTS (src);
   delts = EBITSET_ELTS (dst);


@@ -505,91 +483,74 @@ ebitset_copy (dst, src)
 }
 
 
 }
 
 

-/* Copy bits from bitset SRC to bitset DST.  Return non-zero if
+/* Copy bits from bitset SRC to bitset DST.  Return true if

    bitsets different.  */
    bitsets different.  */

-static inline int
-ebitset_copy_compare (dst, src)
-     bitset dst;
-     bitset src;
+static inline bool
+ebitset_copy_cmp (bitset dst, bitset src)

 {
   if (src == dst)
 {
   if (src == dst)

-    return 0;
+    return false;

 
   if (EBITSET_ZERO_P (dst))
     {
 
   if (EBITSET_ZERO_P (dst))
     {

-      ebitset_copy (dst, src);
-      return ! EBITSET_ZERO_P (src);
+      ebitset_copy_ (dst, src);
+      return !EBITSET_ZERO_P (src);

     }
 
   if (ebitset_equal_p (dst, src))
     }
 
   if (ebitset_equal_p (dst, src))

-    return 0;
-
-  ebitset_copy (dst, src);
-  return 1;
-}
+    return false;

 
 

-
-/* Return size in bits of bitset SRC.  */
-static int
-ebitset_size (src)
-     bitset src;
-{
-  /* Return current size of bitset in bits.  */
-  return EBITSET_SIZE (src) * EBITSET_ELT_BITS;
+  ebitset_copy_ (dst, src);
+  return true;

 }
 
 
 /* Set bit BITNO in bitset DST.  */
 static void
 }
 
 
 /* Set bit BITNO in bitset DST.  */
 static void

-ebitset_set (dst, bitno)
-     bitset dst;
-     bitset_bindex bitno;
+ebitset_set (bitset dst, bitset_bindex bitno)

 {
 {

-  bitset_windex index = bitno / BITSET_WORD_BITS;
+  bitset_windex windex = bitno / BITSET_WORD_BITS;

 
 

-  ebitset_elt_find (dst, index, EBITSET_CREATE);
+  ebitset_elt_find (dst, bitno, EBITSET_CREATE);

 
 

-  dst->cdata[index - dst->cindex] |= (1 << (bitno % BITSET_WORD_BITS));
+  dst->b.cdata[windex - dst->b.cindex] |=
+    (bitset_word) 1 << (bitno % BITSET_WORD_BITS);

 }
 
 
 /* Reset bit BITNO in bitset DST.  */
 static void
 }
 
 
 /* Reset bit BITNO in bitset DST.  */
 static void

-ebitset_reset (dst, bitno)
-     bitset dst;
-     bitset_bindex bitno;
+ebitset_reset (bitset dst, bitset_bindex bitno)

 {
 {

-  bitset_windex index = bitno / BITSET_WORD_BITS;
+  bitset_windex windex = bitno / BITSET_WORD_BITS;

 
 

-  if (!ebitset_elt_find (dst, index, EBITSET_FIND))
-      return;
+  if (!ebitset_elt_find (dst, bitno, EBITSET_FIND))
+    return;

 
 

-  dst->cdata[index - dst->cindex] &= ~(1 << (bitno % BITSET_WORD_BITS));
+  dst->b.cdata[windex - dst->b.cindex] &=
+    ~((bitset_word) 1 << (bitno % BITSET_WORD_BITS));

 
   /* If all the data is zero, perhaps we should remove it now...
 
   /* If all the data is zero, perhaps we should remove it now...

-     However, there could be a good chance that the element will be needed
+     However, there is a good chance that the element will be needed

      again soon.  */
 }
 
 
 /* Test bit BITNO in bitset SRC.  */
      again soon.  */
 }
 
 
 /* Test bit BITNO in bitset SRC.  */

-static int
-ebitset_test (src, bitno)
-     bitset src;
-     bitset_bindex bitno;
+static bool
+ebitset_test (bitset src, bitset_bindex bitno)

 {
 {

-  bitset_windex index = bitno / BITSET_WORD_BITS;
-
-  if (!ebitset_elt_find (src, index, EBITSET_FIND))
-    return 0;
+  bitset_windex windex = bitno / BITSET_WORD_BITS;

 
 

-  return (src->cdata[index - src->cindex] >> (bitno % BITSET_WORD_BITS)) & 1;
+  return (ebitset_elt_find (src, bitno, EBITSET_FIND)
+         && ((src->b.cdata[windex - src->b.cindex]
+              >> (bitno % BITSET_WORD_BITS))
+             & 1));

 }
 
 
 static void
 }
 
 
 static void

-ebitset_free (bset)
-     bitset bset;
+ebitset_free (bitset bset)

 {
   ebitset_zero (bset);
   free (EBITSET_ELTS (bset));
 {
   ebitset_zero (bset);
   free (EBITSET_ELTS (bset));


@@ -597,26 +558,22 @@ ebitset_free (bset)
 
 
 /* Find list of up to NUM bits set in BSET starting from and including
 
 
 /* Find list of up to NUM bits set in BSET starting from and including

-   *NEXT and store in array LIST.  Return with actual number of bits
-   found and with *NEXT indicating where search stopped.  */
-static int
-ebitset_reverse_list (bset, list, num, next)
-     bitset bset;
-     bitset_bindex *list;
-     bitset_bindex num;
-     bitset_bindex *next;
+ *NEXT and store in array LIST.  Return with actual number of bits
+ found and with *NEXT indicating where search stopped.  */
+static bitset_bindex
+ebitset_list_reverse (bitset bset, bitset_bindex *list,
+                     bitset_bindex num, bitset_bindex *next)

 {
   bitset_bindex n_bits;
   bitset_bindex bitno;
   bitset_bindex rbitno;
 {
   bitset_bindex n_bits;
   bitset_bindex bitno;
   bitset_bindex rbitno;

-  unsigned int bitcnt;
-  bitset_bindex bitoff;
-  bitset_windex index;
-  unsigned int eindex;
+  unsigned int bcount;
+  bitset_bindex boffset;

   bitset_windex windex;
   bitset_windex windex;

+  bitset_windex eindex;
+  bitset_windex woffset;

   bitset_bindex count;
   bitset_windex size;
   bitset_bindex count;
   bitset_windex size;

-  bitset_word word;

   ebitset_elts *elts;
 
   if (EBITSET_ZERO_P (bset))
   ebitset_elts *elts;
 
   if (EBITSET_ZERO_P (bset))


@@ -627,75 +584,78 @@ ebitset_reverse_list (bset, list, num, next)
   rbitno = *next;
 
   if (rbitno >= n_bits)
   rbitno = *next;
 
   if (rbitno >= n_bits)

-      return 0;
+    return 0;

 
   elts = EBITSET_ELTS (bset);
 
   bitno = n_bits - (rbitno + 1);
 
 
   elts = EBITSET_ELTS (bset);
 
   bitno = n_bits - (rbitno + 1);
 

-  index = bitno /  BITSET_WORD_BITS;
+  windex = bitno / BITSET_WORD_BITS;

   eindex = bitno / EBITSET_ELT_BITS;
   eindex = bitno / EBITSET_ELT_BITS;

-  windex = index - eindex * EBITSET_ELT_WORDS;
+  woffset = windex - eindex * EBITSET_ELT_WORDS;

 
   /* If num is 1, we could speed things up with a binary search
      of the word of interest.  */
 
   count = 0;
 
   /* If num is 1, we could speed things up with a binary search
      of the word of interest.  */
 
   count = 0;

-  bitcnt = bitno % BITSET_WORD_BITS;
-  bitoff = index * BITSET_WORD_BITS;
+  bcount = bitno % BITSET_WORD_BITS;
+  boffset = windex * BITSET_WORD_BITS;

 
 

-  for (; eindex != ~0U; eindex--)
+  do

     {
       ebitset_elt *elt;
       bitset_word *srcp;
 
       elt = elts[eindex];
     {
       ebitset_elt *elt;
       bitset_word *srcp;
 
       elt = elts[eindex];

-      if (!elt)
-       continue;
-
-      srcp = EBITSET_WORDS (elt);
-
-      for (; windex != ~0U; windex--, bitoff -= BITSET_WORD_BITS,
-            bitcnt = BITSET_WORD_BITS - 1)
+      if (elt)

        {
        {

-         word = srcp[windex] << (BITSET_WORD_BITS - 1 - bitcnt);
+         srcp = EBITSET_WORDS (elt);

 
 

-         for (; word; bitcnt--)
+         do

            {
            {

-             if (word & BITSET_MSB)
+             bitset_word word;
+
+             word = srcp[woffset] << (BITSET_WORD_BITS - 1 - bcount);
+
+             for (; word; bcount--)

                {
                {

-                 list[count++] = bitoff + bitcnt;
-                 if (count >= num)
+                 if (word & BITSET_MSB)

                    {
                    {

-                     *next = n_bits - (bitoff + bitcnt);
-                     return count;
+                     list[count++] = boffset + bcount;
+                     if (count >= num)
+                       {
+                         *next = n_bits - (boffset + bcount);
+                         return count;
+                       }

                    }
                    }

+                 word <<= 1;

                }
                }

-             word <<= 1;
+             boffset -= BITSET_WORD_BITS;
+             bcount = BITSET_WORD_BITS - 1;

            }
            }

+         while (woffset--);

        }
 
        }
 

-      windex = EBITSET_ELT_WORDS;
+      woffset = EBITSET_ELT_WORDS - 1;
+      boffset = eindex * EBITSET_ELT_BITS - BITSET_WORD_BITS;

     }
     }

+  while (eindex--);

 
 

-  *next = n_bits - (bitoff + 1);
+  *next = n_bits - (boffset + 1);

   return count;
 }
 
 
 /* Find list of up to NUM bits set in BSET starting from and including
   return count;
 }
 
 
 /* Find list of up to NUM bits set in BSET starting from and including

-   *NEXT and store in array LIST.  Return with actual number of bits
-   found and with *NEXT indicating where search stopped.  */
-static int
-ebitset_list (bset, list, num, next)
-     bitset bset;
-     bitset_bindex *list;
-     bitset_bindex num;
-     bitset_bindex *next;
+ *NEXT and store in array LIST.  Return with actual number of bits
+ found and with *NEXT indicating where search stopped.  */
+static bitset_bindex
+ebitset_list (bitset bset, bitset_bindex *list,
+             bitset_bindex num, bitset_bindex *next)

 {
   bitset_bindex bitno;
 {
   bitset_bindex bitno;

-  bitset_windex index;
-  unsigned int eindex;
+  bitset_windex windex;
+  bitset_windex eindex;

   bitset_bindex count;
   bitset_windex size;
   ebitset_elt *elt;
   bitset_bindex count;
   bitset_windex size;
   ebitset_elt *elt;


@@ -719,15 +679,15 @@ ebitset_list (bset, list, num, next)
       elt = elts[eindex];
       if (elt)
        {
       elt = elts[eindex];
       if (elt)
        {

-         bitset_windex windex;
+         bitset_windex woffset;

          bitset_word *srcp = EBITSET_WORDS (elt);
 
          bitset_word *srcp = EBITSET_WORDS (elt);
 

-         index = bitno / BITSET_WORD_BITS;
-         windex = eindex / EBITSET_ELT_WORDS;
+         windex = bitno / BITSET_WORD_BITS;
+         woffset = eindex * EBITSET_ELT_WORDS;

 
 

-         for (; (index - windex) < EBITSET_ELT_WORDS; index++)
+         for (; (windex - woffset) < EBITSET_ELT_WORDS; windex++)

            {
            {

-             word = srcp[index - windex] >> (bitno % BITSET_WORD_BITS);
+             word = srcp[windex - woffset] >> (bitno % BITSET_WORD_BITS);

 
              for (; word; bitno++)
                {
 
              for (; word; bitno++)
                {


@@ -742,7 +702,7 @@ ebitset_list (bset, list, num, next)
                    }
                  word >>= 1;
                }
                    }
                  word >>= 1;
                }

-             bitno = (index + 1) * BITSET_WORD_BITS;
+             bitno = (windex + 1) * BITSET_WORD_BITS;

            }
        }
 
            }
        }
 


@@ -756,7 +716,6 @@ ebitset_list (bset, list, num, next)
   for (; eindex < size; eindex++)
     {
       int i;
   for (; eindex < size; eindex++)
     {
       int i;

-      ebitset_elt *elt;

       bitset_word *srcp;
 
       elt = elts[eindex];
       bitset_word *srcp;
 
       elt = elts[eindex];


@@ -764,25 +723,67 @@ ebitset_list (bset, list, num, next)
        continue;
 
       srcp = EBITSET_WORDS (elt);
        continue;
 
       srcp = EBITSET_WORDS (elt);

-      index = eindex * EBITSET_ELT_WORDS;
+      windex = eindex * EBITSET_ELT_WORDS;

 
       if ((count + EBITSET_ELT_BITS) < num)
        {
          /* The coast is clear, plant boot!  */
 
 
       if ((count + EBITSET_ELT_BITS) < num)
        {
          /* The coast is clear, plant boot!  */
 

-         for (i = 0; i < EBITSET_ELT_WORDS; i++, index++)
+#if EBITSET_ELT_WORDS == 2
+         word = srcp[0];
+         if (word)
+           {
+             if (!(word & 0xffff))
+               {
+                 word >>= 16;
+                 bitno += 16;
+               }
+             if (!(word & 0xff))
+               {
+                 word >>= 8;
+                 bitno += 8;
+               }
+             for (; word; bitno++)
+               {
+                 if (word & 1)
+                   list[count++] = bitno;
+                 word >>= 1;
+               }
+           }
+         windex++;
+         bitno = windex * BITSET_WORD_BITS;
+
+         word = srcp[1];
+         if (word)
+           {
+             if (!(word & 0xffff))
+               {
+                 word >>= 16;
+                 bitno += 16;
+               }
+             for (; word; bitno++)
+               {
+                 if (word & 1)
+                   list[count++] = bitno;
+                 word >>= 1;
+               }
+           }
+         windex++;
+         bitno = windex * BITSET_WORD_BITS;
+#else
+         for (i = 0; i < EBITSET_ELT_WORDS; i++, windex++)

            {
            {

-             bitno = index * BITSET_WORD_BITS;
+             bitno = windex * BITSET_WORD_BITS;

 
              word = srcp[i];
              if (word)
                {
 
              word = srcp[i];
              if (word)
                {

-                 if (! (word & 0xffff))
+                 if (!(word & 0xffff))

                    {
                      word >>= 16;
                      bitno += 16;
                    }
                    {
                      word >>= 16;
                      bitno += 16;
                    }

-                 if (! (word & 0xff))
+                 if (!(word & 0xff))

                    {
                      word >>= 8;
                      bitno += 8;
                    {
                      word >>= 8;
                      bitno += 8;


@@ -795,15 +796,16 @@ ebitset_list (bset, list, num, next)
                    }
                }
            }
                    }
                }
            }

+#endif

        }
       else
        {
          /* Tread more carefully since we need to check
             if array overflows.  */
 
        }
       else
        {
          /* Tread more carefully since we need to check
             if array overflows.  */
 

-         for (i = 0; i < EBITSET_ELT_WORDS; i++, index++)
+         for (i = 0; i < EBITSET_ELT_WORDS; i++, windex++)

            {
            {

-             bitno = index * BITSET_WORD_BITS;
+             bitno = windex * BITSET_WORD_BITS;

 
              for (word = srcp[i]; word; bitno++)
                {
 
              for (word = srcp[i]; word; bitno++)
                {


@@ -827,129 +829,202 @@ ebitset_list (bset, list, num, next)
 }
 
 
 }
 
 

-static int
-ebitset_op1 (dst, op)
-     bitset dst;
-     enum bitset_ops op;
+/* Ensure that any unused bits within the last element are clear.  */
+static inline void
+ebitset_unused_clear (bitset dst)

 {
 {

-  bitset_windex j;
-  ebitset_elt *elt;
+  unsigned int last_bit;
+  bitset_bindex n_bits;
+
+  n_bits = BITSET_NBITS_ (dst);
+  last_bit = n_bits % EBITSET_ELT_BITS;

 
 

-  switch (op)
+  if (last_bit)

     {
     {

-    case BITSET_ZERO:
-      ebitset_zero (dst);
-      return 1;
+      bitset_windex eindex;
+      ebitset_elts *elts;
+      ebitset_elt *elt;
+
+      elts = EBITSET_ELTS (dst);

 
 

-    case BITSET_ONES:
-      for (j = 0; j < EBITSET_SIZE (dst); j++)
+      eindex = n_bits / EBITSET_ELT_BITS;
+
+      elt = elts[eindex];
+      if (elt)

        {
        {

-         /* Create new elements if they cannot be found.  Perhaps
-          we should just add pointers to a ones element.  */
-         elt = ebitset_elt_find (dst, j * EBITSET_ELT_WORDS, EBITSET_CREATE);
-         memset (EBITSET_WORDS (elt), ~0, sizeof (EBITSET_WORDS (elt)));
-       }
-      break;
+         bitset_windex windex;
+         bitset_windex woffset;
+         bitset_word *srcp = EBITSET_WORDS (elt);

 
 

-    case BITSET_EMPTY_P:
-      return ! ebitset_weed (dst);
+         windex = n_bits / BITSET_WORD_BITS;
+         woffset = eindex * EBITSET_ELT_WORDS;

 
 

-    default:
-      abort ();
+         srcp[windex - woffset] &= ((bitset_word) 1 << last_bit) - 1;
+         windex++;
+         for (; (windex - woffset) < EBITSET_ELT_WORDS; windex++)
+           srcp[windex - woffset] = 0;
+       }

     }
     }

+}
+
+
+static void
+ebitset_ones (bitset dst)
+{
+  bitset_windex j;
+  ebitset_elt *elt;

 
 

+  for (j = 0; j < EBITSET_SIZE (dst); j++)
+    {
+      /* Create new elements if they cannot be found.  Perhaps
+        we should just add pointers to a ones element?  */
+      elt =
+       ebitset_elt_find (dst, j * EBITSET_ELT_BITS, EBITSET_CREATE);
+      memset (EBITSET_WORDS (elt), -1, sizeof (EBITSET_WORDS (elt)));
+    }

   EBITSET_NONZERO_SET (dst);
   EBITSET_NONZERO_SET (dst);

+  ebitset_unused_clear (dst);
+}
+
+
+static bool
+ebitset_empty_p (bitset dst)
+{
+  ebitset_elts *elts;
+  bitset_windex j;
+
+  if (EBITSET_ZERO_P (dst))
+    return 1;
+
+  elts = EBITSET_ELTS (dst);
+  for (j = 0; j < EBITSET_SIZE (dst); j++)
+    {
+      ebitset_elt *elt = elts[j];
+
+      if (elt)
+       {
+         if (!ebitset_elt_zero_p (elt))
+           return 0;
+         /* Do some weeding as we go.  */
+         ebitset_elt_remove (dst, j);
+       }
+    }
+
+  /* All the bits are zero.  We could shrink the elts.
+     For now just mark DST as known to be zero.  */
+  EBITSET_ZERO_SET (dst);

   return 1;
 }
 
 
   return 1;
 }
 
 

-static int
-ebitset_op2 (dst, src, op)
-     bitset dst;
-     bitset src;
-     enum bitset_ops op;
+static void
+ebitset_not (bitset dst, bitset src)

 {
 {

+  unsigned int i;

   ebitset_elt *selt;
   ebitset_elt *delt;
   ebitset_elt *selt;
   ebitset_elt *delt;

-  unsigned int i;

   bitset_windex j;
 
   bitset_windex j;
 

-  switch (op)
+  ebitset_resize (dst, BITSET_NBITS_ (src));
+
+  for (j = 0; j < EBITSET_SIZE (src); j++)

     {
     {

-    case BITSET_COPY:
-      ebitset_copy (dst, src);
-      break;
+      /* Create new elements for dst if they cannot be found
+        or substitute zero elements if src elements not found.  */
+      selt =
+       ebitset_elt_find (dst, j * EBITSET_ELT_BITS, EBITSET_SUBST);
+      delt =
+       ebitset_elt_find (dst, j * EBITSET_ELT_BITS, EBITSET_CREATE);

 
 

-    case BITSET_NOT:
-      for (j = 0; j < EBITSET_SIZE (src); j++)
-       {
-         /* Create new elements for dst if they cannot be found
-            or substitute zero elements if src elements not found.  */
-         selt = ebitset_elt_find (dst, j * EBITSET_ELT_WORDS, EBITSET_SUBST);
-         delt = ebitset_elt_find (dst, j * EBITSET_ELT_WORDS, EBITSET_CREATE);
+      for (i = 0; i < EBITSET_ELT_WORDS; i++)
+       EBITSET_WORDS (delt)[i] = ~EBITSET_WORDS (selt)[i];
+    }
+  EBITSET_NONZERO_SET (dst);
+  ebitset_unused_clear (dst);
+}

 
 

-         for (i = 0; i < EBITSET_ELT_WORDS; i++)
-           EBITSET_WORDS (delt)[i] = ~EBITSET_WORDS (selt)[i];
-       }
-      break;
-
-    case BITSET_EQUAL_P:
-      return ebitset_equal_p (dst, src);
-
-      /* Return 1 if DST == DST | SRC.  */
-    case BITSET_SUBSET_P:
-      {
-       ebitset_elts *selts;
-       ebitset_elts *delts;
-       bitset_windex ssize;
-       bitset_windex dsize;
-
-       selts = EBITSET_ELTS (src);
-       delts = EBITSET_ELTS (dst);
-
-       ssize = EBITSET_SIZE (src);
-       dsize = EBITSET_SIZE (dst);
-
-       for (j = 0; j < ssize; j++)
-         {
-           ebitset_elt *selt;
-           ebitset_elt *delt;
-
-           selt = j < ssize ? selts[j] : 0;
-           delt = j < dsize ? delts[j] : 0;
-
-           if (! selt && ! delt)
-             continue;
-
-           if (!selt)
-             selt = &ebitset_zero_elts[0];
-           if (!delt)
-             delt = &ebitset_zero_elts[0];
-
-           for (i = 0; i < EBITSET_ELT_WORDS; i++)
-             if (EBITSET_WORDS (delt)[i]
-                 != (EBITSET_WORDS (selt)[i] | EBITSET_WORDS (delt)[i]))
-               return 0;
-         }
-       return 1;
-      }
-      break;

 
 

-    default:
-      abort ();
+/* Is DST == DST | SRC?  */
+static bool
+ebitset_subset_p (bitset dst, bitset src)
+{
+  bitset_windex j;
+  ebitset_elts *selts;
+  ebitset_elts *delts;
+  bitset_windex ssize;
+  bitset_windex dsize;
+
+  selts = EBITSET_ELTS (src);
+  delts = EBITSET_ELTS (dst);
+
+  ssize = EBITSET_SIZE (src);
+  dsize = EBITSET_SIZE (dst);
+
+  for (j = 0; j < ssize; j++)
+    {
+      unsigned int i;
+      ebitset_elt *selt;
+      ebitset_elt *delt;
+
+      selt = j < ssize ? selts[j] : 0;
+      delt = j < dsize ? delts[j] : 0;
+
+      if (!selt && !delt)
+       continue;
+
+      if (!selt)
+       selt = &ebitset_zero_elts[0];
+      if (!delt)
+       delt = &ebitset_zero_elts[0];
+
+      for (i = 0; i < EBITSET_ELT_WORDS; i++)
+       if (EBITSET_WORDS (delt)[i]
+           != (EBITSET_WORDS (selt)[i] | EBITSET_WORDS (delt)[i]))
+         return false;

     }
     }

+  return true;
+}

 
 

-  EBITSET_NONZERO_SET (dst);
-  return 1;
+
+/* Is DST & SRC == 0?  */
+static bool
+ebitset_disjoint_p (bitset dst, bitset src)
+{
+  bitset_windex j;
+  ebitset_elts *selts;
+  ebitset_elts *delts;
+  bitset_windex ssize;
+  bitset_windex dsize;
+
+  selts = EBITSET_ELTS (src);
+  delts = EBITSET_ELTS (dst);
+
+  ssize = EBITSET_SIZE (src);
+  dsize = EBITSET_SIZE (dst);
+
+  for (j = 0; j < ssize; j++)
+    {
+      unsigned int i;
+      ebitset_elt *selt;
+      ebitset_elt *delt;
+
+      selt = j < ssize ? selts[j] : 0;
+      delt = j < dsize ? delts[j] : 0;
+
+      if (!selt || !delt)
+       continue;
+
+      for (i = 0; i < EBITSET_ELT_WORDS; i++)
+       if ((EBITSET_WORDS (selt)[i] & EBITSET_WORDS (delt)[i]))
+         return false;
+    }
+  return true;

 }
 
 
 }
 
 

-static int
-ebitset_op3 (dst, src1, src2, op)
-     bitset dst;
-     bitset src1;
-     bitset src2;
-     enum bitset_ops op;
+
+static bool
+ebitset_op3_cmp (bitset dst, bitset src1, bitset src2, enum bitset_ops op)

 {
   bitset_windex ssize1;
   bitset_windex ssize2;
 {
   bitset_windex ssize1;
   bitset_windex ssize2;


@@ -961,39 +1036,11 @@ ebitset_op3 (dst, src1, src2, op)
   bitset_word *srcp1;
   bitset_word *srcp2;
   bitset_word *dstp;
   bitset_word *srcp1;
   bitset_word *srcp2;
   bitset_word *dstp;

-  int changed = 0;
+  bool changed = false;

   unsigned int i;
   bitset_windex j;
 
   unsigned int i;
   bitset_windex j;
 

-  /* Fast track common, simple cases.  */
-  if (EBITSET_ZERO_P (src2))
-    {
-      if (op == BITSET_AND)
-       {
-         ebitset_weed (dst);
-         changed = EBITSET_ZERO_P (dst);
-         ebitset_zero (dst);
-         return changed;
-       }
-      else if (op == BITSET_ANDN || op == BITSET_OR || op == BITSET_XOR)
-       {
-         return ebitset_copy_compare (dst, src1);
-       }
-    }
-  else if (EBITSET_ZERO_P (src1))
-    {
-      if (op == BITSET_AND || op == BITSET_ANDN)
-       {
-         ebitset_weed (dst);
-         changed = EBITSET_ZERO_P (dst);
-         ebitset_zero (dst);
-         return changed;
-       }
-      else if (op == BITSET_OR || op == BITSET_XOR)
-       {
-         return ebitset_copy_compare (dst, src2);
-       }
-    }
+  ebitset_resize (dst, max (BITSET_NBITS_ (src1), BITSET_NBITS_ (src2)));

 
   ssize1 = EBITSET_SIZE (src1);
   ssize2 = EBITSET_SIZE (src2);
 
   ssize1 = EBITSET_SIZE (src1);
   ssize2 = EBITSET_SIZE (src2);


@@ -1002,9 +1049,6 @@ ebitset_op3 (dst, src1, src2, op)
   if (size < ssize2)
     size = ssize2;
 
   if (size < ssize2)
     size = ssize2;
 

-  if (size > dsize)
-      ebitset_elts_grow (dst, size - dsize);
-

   selts1 = EBITSET_ELTS (src1);
   selts2 = EBITSET_ELTS (src2);
   delts = EBITSET_ELTS (dst);
   selts1 = EBITSET_ELTS (src1);
   selts2 = EBITSET_ELTS (src2);
   delts = EBITSET_ELTS (dst);


@@ -1019,11 +1063,11 @@ ebitset_op3 (dst, src1, src2, op)
       selt2 = j < ssize2 ? selts2[j] : 0;
       delt = j < dsize ? delts[j] : 0;
 
       selt2 = j < ssize2 ? selts2[j] : 0;
       delt = j < dsize ? delts[j] : 0;
 

-      if (! selt1 && ! selt2)
+      if (!selt1 && !selt2)

        {
          if (delt)
            {
        {
          if (delt)
            {

-             changed = 1;
+             changed = true;

              ebitset_elt_remove (dst, j);
            }
          continue;
              ebitset_elt_remove (dst, j);
            }
          continue;


@@ -1043,76 +1087,63 @@ ebitset_op3 (dst, src1, src2, op)
       dstp = EBITSET_WORDS (delt);
       switch (op)
        {
       dstp = EBITSET_WORDS (delt);
       switch (op)
        {

-       case BITSET_OR:
+       default:
+         abort ();
+
+       case BITSET_OP_OR:

          for (i = 0; i < EBITSET_ELT_WORDS; i++, dstp++)
            {
              bitset_word tmp = *srcp1++ | *srcp2++;
 
              if (*dstp != tmp)
                {
          for (i = 0; i < EBITSET_ELT_WORDS; i++, dstp++)
            {
              bitset_word tmp = *srcp1++ | *srcp2++;
 
              if (*dstp != tmp)
                {

-                 changed = 1;
+                 changed = true;

                  *dstp = tmp;
                }
            }
          break;
 
                  *dstp = tmp;
                }
            }
          break;
 

-       case BITSET_AND:
+       case BITSET_OP_AND:

          for (i = 0; i < EBITSET_ELT_WORDS; i++, dstp++)
            {
              bitset_word tmp = *srcp1++ & *srcp2++;
 
              if (*dstp != tmp)
                {
          for (i = 0; i < EBITSET_ELT_WORDS; i++, dstp++)
            {
              bitset_word tmp = *srcp1++ & *srcp2++;
 
              if (*dstp != tmp)
                {

-                 changed = 1;
+                 changed = true;

                  *dstp = tmp;
                }
            }
          break;
 
                  *dstp = tmp;
                }
            }
          break;
 

-       case BITSET_XOR:
+       case BITSET_OP_XOR:

          for (i = 0; i < EBITSET_ELT_WORDS; i++, dstp++)
            {
              bitset_word tmp = *srcp1++ ^ *srcp2++;
 
              if (*dstp != tmp)
                {
          for (i = 0; i < EBITSET_ELT_WORDS; i++, dstp++)
            {
              bitset_word tmp = *srcp1++ ^ *srcp2++;
 
              if (*dstp != tmp)
                {

-                 changed = 1;
+                 changed = true;

                  *dstp = tmp;
                }
            }
          break;
 
                  *dstp = tmp;
                }
            }
          break;
 

-       case BITSET_ANDN:
+       case BITSET_OP_ANDN:

          for (i = 0; i < EBITSET_ELT_WORDS; i++, dstp++)
            {
              bitset_word tmp = *srcp1++ & ~(*srcp2++);
 
              if (*dstp != tmp)
                {
          for (i = 0; i < EBITSET_ELT_WORDS; i++, dstp++)
            {
              bitset_word tmp = *srcp1++ & ~(*srcp2++);
 
              if (*dstp != tmp)
                {

-                 changed = 1;
-                 *dstp = tmp;
-               }
-           }
-         break;
-
-       case BITSET_ORN:
-         for (i = 0; i < EBITSET_ELT_WORDS; i++, dstp++)
-           {
-             bitset_word tmp = *srcp1++ | ~(*srcp2++);
-
-             if (*dstp != tmp)
-               {
-                 changed = 1;
+                 changed = true;

                  *dstp = tmp;
                }
            }
          break;
                  *dstp = tmp;
                }
            }
          break;

-
-       default:
-         abort ();

        }
 
        }
 

-      if (! ebitset_elt_zero_p (delt))
+      if (!ebitset_elt_zero_p (delt))

        {
          ebitset_elt_add (dst, delt, j);
        }
        {
          ebitset_elt_add (dst, delt, j);
        }


@@ -1127,7 +1158,7 @@ ebitset_op3 (dst, src1, src2, op)
     {
       ebitset_elt *delt;
 
     {
       ebitset_elt *delt;
 

-      changed = 1;
+      changed = true;

 
       delt = delts[j];
 
 
       delt = delts[j];
 


@@ -1140,106 +1171,194 @@ ebitset_op3 (dst, src1, src2, op)
 }
 
 
 }
 
 

-static int
-ebitset_op4 (dst, src1, src2, src3, op)
-     bitset dst;
-     bitset src1;
-     bitset src2;
-     bitset src3;
-     enum bitset_ops op;
+static bool
+ebitset_and_cmp (bitset dst, bitset src1, bitset src2)
+{
+  bool changed;
+
+  if (EBITSET_ZERO_P (src2))
+    {
+      ebitset_weed (dst);
+      changed = EBITSET_ZERO_P (dst);
+      ebitset_zero (dst);
+      return changed;
+    }
+  else if (EBITSET_ZERO_P (src1))
+    {
+      ebitset_weed (dst);
+      changed = EBITSET_ZERO_P (dst);
+      ebitset_zero (dst);
+      return changed;
+    }
+  return ebitset_op3_cmp (dst, src1, src2, BITSET_OP_AND);
+}
+
+
+static void
+ebitset_and (bitset dst, bitset src1, bitset src2)

 {
 {

-  int changed = 0;
-  bitset tmp;
+  ebitset_and_cmp (dst, src1, src2);
+}
+

 
 

-  tmp = bitset_create (BITSET_LIST, 0);
+static bool
+ebitset_andn_cmp (bitset dst, bitset src1, bitset src2)
+{
+  bool changed;

 
 

-  switch (op)
+  if (EBITSET_ZERO_P (src2))
+    {
+      return ebitset_copy_cmp (dst, src1);
+    }
+  else if (EBITSET_ZERO_P (src1))

     {
     {

-    case BITSET_OR_AND:
-      bitset_or (tmp, src1, src2);
-      changed = bitset_and (dst, src3, tmp);
-      break;
+      ebitset_weed (dst);
+      changed = EBITSET_ZERO_P (dst);
+      ebitset_zero (dst);
+      return changed;
+    }
+  return ebitset_op3_cmp (dst, src1, src2, BITSET_OP_ANDN);
+}

 
 

-    case BITSET_AND_OR:
-      bitset_and (tmp, src1, src2);
-      changed = bitset_or (dst, src3, tmp);
-      break;

 
 

-    case BITSET_ANDN_OR:
-      bitset_andn (tmp, src1, src2);
-      changed = bitset_or (dst, src3, tmp);
-      break;
+static void
+ebitset_andn (bitset dst, bitset src1, bitset src2)
+{
+  ebitset_andn_cmp (dst, src1, src2);
+}

 
 

-    default:
-      abort ();
+
+static bool
+ebitset_or_cmp (bitset dst, bitset src1, bitset src2)
+{
+  if (EBITSET_ZERO_P (src2))
+    {
+      return ebitset_copy_cmp (dst, src1);
+    }
+  else if (EBITSET_ZERO_P (src1))
+    {
+      return ebitset_copy_cmp (dst, src2);

     }
     }

+  return ebitset_op3_cmp (dst, src1, src2, BITSET_OP_OR);
+}

 
 

-  bitset_free (tmp);
-  EBITSET_NONZERO_SET (dst);
-  return changed;
+
+static void
+ebitset_or (bitset dst, bitset src1, bitset src2)
+{
+  ebitset_or_cmp (dst, src1, src2);
+}
+
+
+static bool
+ebitset_xor_cmp (bitset dst, bitset src1, bitset src2)
+{
+  if (EBITSET_ZERO_P (src2))
+    {
+      return ebitset_copy_cmp (dst, src1);
+    }
+  else if (EBITSET_ZERO_P (src1))
+    {
+      return ebitset_copy_cmp (dst, src2);
+    }
+  return ebitset_op3_cmp (dst, src1, src2, BITSET_OP_XOR);
+}
+
+
+static void
+ebitset_xor (bitset dst, bitset src1, bitset src2)
+{
+  ebitset_xor_cmp (dst, src1, src2);
+}
+
+
+static void
+ebitset_copy (bitset dst, bitset src)
+{
+  if (BITSET_COMPATIBLE_ (dst, src))
+      ebitset_copy_ (dst, src);
+  else
+      bitset_copy_ (dst, src);

 }
 
 
 /* Vector of operations for linked-list bitsets.  */
 }
 
 
 /* Vector of operations for linked-list bitsets.  */

-struct bitset_ops_struct ebitset_ops =
-  {
-    ebitset_set,
-    ebitset_reset,
-    ebitset_test,
-    ebitset_size,
-    ebitset_op1,
-    ebitset_op2,
-    ebitset_op3,
-    ebitset_op4,
-    ebitset_list,
-    ebitset_reverse_list,
-    ebitset_free,
-    BITSET_TABLE
-  };
+struct bitset_vtable ebitset_vtable = {
+  ebitset_set,
+  ebitset_reset,
+  bitset_toggle_,
+  ebitset_test,
+  ebitset_resize,
+  bitset_size_,
+  bitset_count_,
+  ebitset_empty_p,
+  ebitset_ones,
+  ebitset_zero,
+  ebitset_copy,
+  ebitset_disjoint_p,
+  ebitset_equal_p,
+  ebitset_not,
+  ebitset_subset_p,
+  ebitset_and,
+  ebitset_and_cmp,
+  ebitset_andn,
+  ebitset_andn_cmp,
+  ebitset_or,
+  ebitset_or_cmp,
+  ebitset_xor,
+  ebitset_xor_cmp,
+  bitset_and_or_,
+  bitset_and_or_cmp_,
+  bitset_andn_or_,
+  bitset_andn_or_cmp_,
+  bitset_or_and_,
+  bitset_or_and_cmp_,
+  ebitset_list,
+  ebitset_list_reverse,
+  ebitset_free,
+  BITSET_TABLE
+};

 
 
 /* Return size of initial structure.  */
 
 
 /* Return size of initial structure.  */

-int
-ebitset_bytes (n_bits)
-     bitset_bindex n_bits ATTRIBUTE_UNUSED;
+size_t
+ebitset_bytes (bitset_bindex n_bits ATTRIBUTE_UNUSED)

 {
 {

-  return sizeof (struct bitset_struct);
+  return sizeof (struct ebitset_struct);

 }
 
 
 /* Initialize a bitset.  */
 
 bitset
 }
 
 
 /* Initialize a bitset.  */
 
 bitset

-ebitset_init (bset, n_bits)
-     bitset bset;
-     bitset_bindex n_bits;
+ebitset_init (bitset bset, bitset_bindex n_bits)

 {
 {

-  unsigned int size;
+  bitset_windex size;

 
 

-  bset->ops = &ebitset_ops;
+  bset->b.vtable = &ebitset_vtable;

 
 

-  bset->csize = EBITSET_ELT_WORDS;
+  bset->b.csize = EBITSET_ELT_WORDS;

 
   EBITSET_ZERO_SET (bset);
 
   size = n_bits ? (n_bits + EBITSET_ELT_BITS - 1) / EBITSET_ELT_BITS
     : EBITSET_INITIAL_SIZE;
 
 
   EBITSET_ZERO_SET (bset);
 
   size = n_bits ? (n_bits + EBITSET_ELT_BITS - 1) / EBITSET_ELT_BITS
     : EBITSET_INITIAL_SIZE;
 

-  EBITSET_SIZE (bset) = 0;
+  EBITSET_ASIZE (bset) = 0;

   EBITSET_ELTS (bset) = 0;
   EBITSET_ELTS (bset) = 0;

-  ebitset_elts_grow (bset, size);
+  ebitset_resize (bset, n_bits);

 
   return bset;
 }
 
 
 void
 
   return bset;
 }
 
 
 void

-ebitset_release_memory ()
+ebitset_release_memory (void)

 {
   ebitset_free_list = 0;
   if (ebitset_obstack_init)
     {
 {
   ebitset_free_list = 0;
   if (ebitset_obstack_init)
     {

-      ebitset_obstack_init = 0;
+      ebitset_obstack_init = false;

       obstack_free (&ebitset_obstack, NULL);
     }
 }
       obstack_free (&ebitset_obstack, NULL);
     }
 }