X-Git-Url: https://git.saurik.com/bison.git/blobdiff_plain/6aa452a643c65a8df244013e05d41854531ec762..deef2a0a4d97b580fe45a02da328b94ce32538b1:/lib/abitset.c

diff --git a/lib/abitset.c b/lib/abitset.c
index 9eb2eeb9..b03ff120 100644
--- a/lib/abitset.c
+++ b/lib/abitset.c
@@ -1,10 +1,10 @@
 /* Array bitsets.
-   Copyright (C) 2002 Free Software Foundation, Inc.
+   Copyright (C) 2002, 2003, 2006 Free Software Foundation, Inc.
    Contributed by Michael Hayes (m.hayes@elec.canterbury.ac.nz).
 
-   This program is free software; you can redistribute it and/or modify
+   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
+   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,
@@ -13,72 +13,38 @@
    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. 
-*/
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
 
-#ifdef HAVE_CONFIG_H
-#include "config.h"
-#endif
+#include <config.h>
 
 #include "abitset.h"
+#include <stddef.h>
 #include <stdlib.h>
 #include <string.h>
 
 /* This file implements fixed size bitsets stored as an array
    of words.  Any unused bits in the last word must be zero.  */
 
-typedef struct abitset_struct
-{
-  unsigned int n_bits;	/* Number of bits.  */
-  bitset_word words[1];	/* The array of bits.  */
-}
-*abitset;
-
-
-struct bitset_struct
-{
-  struct bbitset_struct b;
-  struct abitset_struct a;
-};
-
-static void abitset_unused_clear PARAMS ((bitset));
-
-static int abitset_small_list PARAMS ((bitset, bitset_bindex *, bitset_bindex,
-				       bitset_bindex *));
-
-static void abitset_set PARAMS ((bitset, bitset_bindex));
-static void abitset_reset PARAMS ((bitset, bitset_bindex));
-static int abitset_test PARAMS ((bitset, bitset_bindex));
-static int abitset_size PARAMS ((bitset));
-static int abitset_list PARAMS ((bitset, bitset_bindex *, bitset_bindex,
-				 bitset_bindex *));
-static int abitset_list_reverse
-PARAMS ((bitset, bitset_bindex *, bitset_bindex, bitset_bindex *));
-
 #define ABITSET_N_WORDS(N) (((N) + BITSET_WORD_BITS - 1) / BITSET_WORD_BITS)
 #define ABITSET_WORDS(X) ((X)->a.words)
-#define ABITSET_N_BITS(X) ((X)->a.n_bits)
 
 
-/* Return size in bits of bitset SRC.  */
-static int
-abitset_size (src)
-     bitset src;
+static bitset_bindex
+abitset_resize (bitset src, bitset_bindex size)
 {
-  return ABITSET_N_BITS (src);
-}
+    /* These bitsets have a fixed size.  */
+    if (BITSET_SIZE_ (src) != size)
+      abort ();
 
+    return size;
+}
 
 /* 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
-abitset_small_list (src, list, num, next)
-     bitset src;
-     bitset_bindex *list;
-     bitset_bindex num;
-     bitset_bindex *next;
+static bitset_bindex
+abitset_small_list (bitset src, bitset_bindex *list,
+		    bitset_bindex num, bitset_bindex *next)
 {
   bitset_bindex bitno;
   bitset_bindex count;
@@ -91,7 +57,7 @@ abitset_small_list (src, list, num, next)
   if (!word)
     return 0;
 
-  size = ABITSET_N_BITS (src);
+  size = BITSET_SIZE_ (src);
   bitno = *next;
   if (bitno >= size)
     return 0;
@@ -134,38 +100,34 @@ abitset_small_list (src, list, num, next)
 
 /* Set bit BITNO in bitset DST.  */
 static void
-abitset_set (dst, bitno)
-     bitset dst ATTRIBUTE_UNUSED;
-     bitset_bindex bitno ATTRIBUTE_UNUSED;
+abitset_set (bitset dst ATTRIBUTE_UNUSED, bitset_bindex bitno ATTRIBUTE_UNUSED)
 {
-  /* This should never occur for abitsets since we should always
-     hit the cache.  */
+  /* This should never occur for abitsets since we should always hit
+     the cache.  It is likely someone is trying to access outside the
+     bounds of the bitset.  */
   abort ();
 }
 
 
 /* Reset bit BITNO in bitset DST.  */
 static void
-abitset_reset (dst, bitno)
-     bitset dst ATTRIBUTE_UNUSED;
-     bitset_bindex bitno ATTRIBUTE_UNUSED;
+abitset_reset (bitset dst ATTRIBUTE_UNUSED,
+	       bitset_bindex bitno ATTRIBUTE_UNUSED)
 {
-  /* This should never occur for abitsets since we should always
-     hit the cache.  */
-  abort ();
+  /* This should never occur for abitsets since we should always hit
+     the cache.  It is likely someone is trying to access outside the
+     bounds of the bitset.  Since the bit is zero anyway, let it pass.  */
 }
 
 
 /* Test bit BITNO in bitset SRC.  */
-static int
-abitset_test (src, bitno)
-     bitset src ATTRIBUTE_UNUSED;
-     bitset_bindex bitno ATTRIBUTE_UNUSED;
+static bool
+abitset_test (bitset src ATTRIBUTE_UNUSED,
+	      bitset_bindex bitno ATTRIBUTE_UNUSED)
 {
   /* This should never occur for abitsets since we should always
      hit the cache.  */
-  abort ();
-  return 0;
+  return false;
 }
 
 
@@ -173,12 +135,9 @@ abitset_test (src, bitno)
    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
-abitset_list_reverse (src, list, num, next)
-     bitset src;
-     bitset_bindex *list;
-     bitset_bindex num;
-     bitset_bindex *next;
+static bitset_bindex
+abitset_list_reverse (bitset src, bitset_bindex *list,
+		      bitset_bindex num, bitset_bindex *next)
 {
   bitset_bindex bitno;
   bitset_bindex rbitno;
@@ -187,7 +146,7 @@ abitset_list_reverse (src, list, num, next)
   unsigned int bitcnt;
   bitset_bindex bitoff;
   bitset_word *srcp = ABITSET_WORDS (src);
-  bitset_bindex n_bits = ABITSET_N_BITS (src);
+  bitset_bindex n_bits = BITSET_SIZE_ (src);
 
   rbitno = *next;
 
@@ -236,12 +195,9 @@ abitset_list_reverse (src, list, num, next)
 /* 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
-abitset_list (src, list, num, next)
-     bitset src;
-     bitset_bindex *list;
-     bitset_bindex num;
-     bitset_bindex *next;
+static bitset_bindex
+abitset_list (bitset src, bitset_bindex *list,
+	      bitset_bindex num, bitset_bindex *next)
 {
   bitset_bindex bitno;
   bitset_bindex count;
@@ -269,7 +225,7 @@ abitset_list (src, list, num, next)
     }
   else
     {
-      if (bitno >= ABITSET_N_BITS (src))
+      if (bitno >= BITSET_SIZE_ (src))
 	return 0;
 
       windex = bitno / BITSET_WORD_BITS;
@@ -341,12 +297,11 @@ abitset_list (src, list, num, next)
 
 /* Ensure that any unused bits within the last word are clear.  */
 static inline void
-abitset_unused_clear (dst)
-     bitset dst;
+abitset_unused_clear (bitset dst)
 {
   unsigned int last_bit;
 
-  last_bit = ABITSET_N_BITS (dst) % BITSET_WORD_BITS;
+  last_bit = BITSET_SIZE_ (dst) % BITSET_WORD_BITS;
   if (last_bit)
     ABITSET_WORDS (dst)[dst->b.csize - 1] &=
       ((bitset_word) 1 << last_bit) - 1;
@@ -354,11 +309,10 @@ abitset_unused_clear (dst)
 
 
 static void
-abitset_ones (dst)
-     bitset dst;
+abitset_ones (bitset dst)
 {
   bitset_word *dstp = ABITSET_WORDS (dst);
-  unsigned int bytes;
+  size_t bytes;
 
   bytes = sizeof (bitset_word) * dst->b.csize;
 
@@ -368,11 +322,10 @@ abitset_ones (dst)
 
 
 static void
-abitset_zero (dst)
-     bitset dst;
+abitset_zero (bitset dst)
 {
   bitset_word *dstp = ABITSET_WORDS (dst);
-  unsigned int bytes;
+  size_t bytes;
 
   bytes = sizeof (bitset_word) * dst->b.csize;
 
@@ -380,25 +333,22 @@ abitset_zero (dst)
 }
 
 
-static int
-abitset_empty_p (dst)
-     bitset dst;
+static bool
+abitset_empty_p (bitset dst)
 {
-  unsigned int i;
+  bitset_windex i;
   bitset_word *dstp = ABITSET_WORDS (dst);
 
   for (i = 0; i < dst->b.csize; i++)
     if (dstp[i])
-      return 0;
+      return false;
 
-  return 1;
+  return true;
 }
 
 
 static void
-abitset_copy1 (dst, src)
-     bitset dst;
-     bitset src;
+abitset_copy1 (bitset dst, bitset src)
 {
   bitset_word *srcp = ABITSET_WORDS (src);
   bitset_word *dstp = ABITSET_WORDS (dst);
@@ -411,11 +361,9 @@ abitset_copy1 (dst, src)
 
 
 static void
-abitset_not (dst, src)
-     bitset dst;
-     bitset src;
+abitset_not (bitset dst, bitset src)
 {
-  unsigned int i;
+  bitset_windex i;
   bitset_word *srcp = ABITSET_WORDS (src);
   bitset_word *dstp = ABITSET_WORDS (dst);
   bitset_windex size = dst->b.csize;
@@ -425,66 +373,57 @@ abitset_not (dst, src)
   abitset_unused_clear (dst);
 }
 
- 
-static int
-abitset_equal_p (dst, src)
-     bitset dst;
-     bitset src;
+
+static bool
+abitset_equal_p (bitset dst, bitset src)
 {
-  unsigned int i;
+  bitset_windex i;
   bitset_word *srcp = ABITSET_WORDS (src);
   bitset_word *dstp = ABITSET_WORDS (dst);
   bitset_windex size = dst->b.csize;
 
   for (i = 0; i < size; i++)
       if (*srcp++ != *dstp++)
-	  return 0;
-  return 1;
+	  return false;
+  return true;
 }
 
 
-static int
-abitset_subset_p (dst, src)
-     bitset dst;
-     bitset src;
+static bool
+abitset_subset_p (bitset dst, bitset src)
 {
-  unsigned int i;
+  bitset_windex i;
   bitset_word *srcp = ABITSET_WORDS (src);
   bitset_word *dstp = ABITSET_WORDS (dst);
   bitset_windex size = dst->b.csize;
-  
+
   for (i = 0; i < size; i++, dstp++, srcp++)
       if (*dstp != (*srcp | *dstp))
-	  return 0;
-  return 1;
+	  return false;
+  return true;
 }
 
 
-static int
-abitset_disjoint_p (dst, src)
-     bitset dst;
-     bitset src;
+static bool
+abitset_disjoint_p (bitset dst, bitset src)
 {
-  unsigned int i;
+  bitset_windex i;
   bitset_word *srcp = ABITSET_WORDS (src);
   bitset_word *dstp = ABITSET_WORDS (dst);
   bitset_windex size = dst->b.csize;
 
   for (i = 0; i < size; i++)
       if (*srcp++ & *dstp++)
-	  return 0;
+	  return false;
 
-  return 1;
+  return true;
 }
 
 
 static void
-abitset_and (dst, src1, src2)
-     bitset dst;
-     bitset src1;
-     bitset src2;
+abitset_and (bitset dst, bitset src1, bitset src2)
 {
-  unsigned int i;
+  bitset_windex i;
   bitset_word *src1p = ABITSET_WORDS (src1);
   bitset_word *src2p = ABITSET_WORDS (src2);
   bitset_word *dstp = ABITSET_WORDS (dst);
@@ -495,14 +434,11 @@ abitset_and (dst, src1, src2)
 }
 
 
-static int
-abitset_and_cmp (dst, src1, src2)
-     bitset dst;
-     bitset src1;
-     bitset src2;
+static bool
+abitset_and_cmp (bitset dst, bitset src1, bitset src2)
 {
-  unsigned int i;
-  int changed = 0;
+  bitset_windex i;
+  bool changed = false;
   bitset_word *src1p = ABITSET_WORDS (src1);
   bitset_word *src2p = ABITSET_WORDS (src2);
   bitset_word *dstp = ABITSET_WORDS (dst);
@@ -511,10 +447,10 @@ abitset_and_cmp (dst, src1, src2)
   for (i = 0; i < size; i++, dstp++)
     {
       bitset_word tmp = *src1p++ & *src2p++;
-      
+
       if (*dstp != tmp)
 	{
-	  changed = 1;
+	  changed = true;
 	  *dstp = tmp;
 	}
     }
@@ -523,12 +459,9 @@ abitset_and_cmp (dst, src1, src2)
 
 
 static void
-abitset_andn (dst, src1, src2)
-     bitset dst;
-     bitset src1;
-     bitset src2;
+abitset_andn (bitset dst, bitset src1, bitset src2)
 {
-  unsigned int i;
+  bitset_windex i;
   bitset_word *src1p = ABITSET_WORDS (src1);
   bitset_word *src2p = ABITSET_WORDS (src2);
   bitset_word *dstp = ABITSET_WORDS (dst);
@@ -539,26 +472,23 @@ abitset_andn (dst, src1, src2)
 }
 
 
-static int
-abitset_andn_cmp (dst, src1, src2)
-     bitset dst;
-     bitset src1;
-     bitset src2;
+static bool
+abitset_andn_cmp (bitset dst, bitset src1, bitset src2)
 {
-  unsigned int i;
-  int changed = 0;
+  bitset_windex i;
+  bool changed = false;
   bitset_word *src1p = ABITSET_WORDS (src1);
   bitset_word *src2p = ABITSET_WORDS (src2);
   bitset_word *dstp = ABITSET_WORDS (dst);
   bitset_windex size = dst->b.csize;
-  
+
   for (i = 0; i < size; i++, dstp++)
     {
       bitset_word tmp = *src1p++ & ~(*src2p++);
-      
+
       if (*dstp != tmp)
 	{
-	  changed = 1;
+	  changed = true;
 	  *dstp = tmp;
 	}
     }
@@ -567,12 +497,9 @@ abitset_andn_cmp (dst, src1, src2)
 
 
 static void
-abitset_or (dst, src1, src2)
-     bitset dst;
-     bitset src1;
-     bitset src2;
+abitset_or (bitset dst, bitset src1, bitset src2)
 {
-  unsigned int i;
+  bitset_windex i;
   bitset_word *src1p = ABITSET_WORDS (src1);
   bitset_word *src2p = ABITSET_WORDS (src2);
   bitset_word *dstp = ABITSET_WORDS (dst);
@@ -583,14 +510,11 @@ abitset_or (dst, src1, src2)
 }
 
 
-static int
-abitset_or_cmp (dst, src1, src2)
-     bitset dst;
-     bitset src1;
-     bitset src2;
+static bool
+abitset_or_cmp (bitset dst, bitset src1, bitset src2)
 {
-  unsigned int i;
-  int changed = 0;
+  bitset_windex i;
+  bool changed = false;
   bitset_word *src1p = ABITSET_WORDS (src1);
   bitset_word *src2p = ABITSET_WORDS (src2);
   bitset_word *dstp = ABITSET_WORDS (dst);
@@ -599,10 +523,10 @@ abitset_or_cmp (dst, src1, src2)
   for (i = 0; i < size; i++, dstp++)
     {
       bitset_word tmp = *src1p++ | *src2p++;
-      
+
       if (*dstp != tmp)
 	{
-	  changed = 1;
+	  changed = true;
 	  *dstp = tmp;
 	}
     }
@@ -611,12 +535,9 @@ abitset_or_cmp (dst, src1, src2)
 
 
 static void
-abitset_xor (dst, src1, src2)
-     bitset dst;
-     bitset src1;
-     bitset src2;
+abitset_xor (bitset dst, bitset src1, bitset src2)
 {
-  unsigned int i;
+  bitset_windex i;
   bitset_word *src1p = ABITSET_WORDS (src1);
   bitset_word *src2p = ABITSET_WORDS (src2);
   bitset_word *dstp = ABITSET_WORDS (dst);
@@ -627,14 +548,11 @@ abitset_xor (dst, src1, src2)
 }
 
 
-static int
-abitset_xor_cmp (dst, src1, src2)
-     bitset dst;
-     bitset src1;
-     bitset src2;
+static bool
+abitset_xor_cmp (bitset dst, bitset src1, bitset src2)
 {
-  unsigned int i;
-  int changed = 0;
+  bitset_windex i;
+  bool changed = false;
   bitset_word *src1p = ABITSET_WORDS (src1);
   bitset_word *src2p = ABITSET_WORDS (src2);
   bitset_word *dstp = ABITSET_WORDS (dst);
@@ -643,10 +561,10 @@ abitset_xor_cmp (dst, src1, src2)
   for (i = 0; i < size; i++, dstp++)
     {
       bitset_word tmp = *src1p++ ^ *src2p++;
-      
+
       if (*dstp != tmp)
 	{
-	  changed = 1;
+	  changed = true;
 	  *dstp = tmp;
 	}
     }
@@ -655,46 +573,38 @@ abitset_xor_cmp (dst, src1, src2)
 
 
 static void
-abitset_and_or (dst, src1, src2, src3)
-     bitset dst;
-     bitset src1;
-     bitset src2;
-     bitset src3;
+abitset_and_or (bitset dst, bitset src1, bitset src2, bitset src3)
 {
-  unsigned int i;
+  bitset_windex i;
   bitset_word *src1p = ABITSET_WORDS (src1);
   bitset_word *src2p = ABITSET_WORDS (src2);
   bitset_word *src3p = ABITSET_WORDS (src3);
   bitset_word *dstp = ABITSET_WORDS (dst);
   bitset_windex size = dst->b.csize;
-  
+
   for (i = 0; i < size; i++)
       *dstp++ = (*src1p++ & *src2p++) | *src3p++;
 }
 
 
-static int
-abitset_and_or_cmp (dst, src1, src2, src3)
-     bitset dst;
-     bitset src1;
-     bitset src2;
-     bitset src3;
+static bool
+abitset_and_or_cmp (bitset dst, bitset src1, bitset src2, bitset src3)
 {
-  unsigned int i;
-  int changed = 0;
+  bitset_windex i;
+  bool changed = false;
   bitset_word *src1p = ABITSET_WORDS (src1);
   bitset_word *src2p = ABITSET_WORDS (src2);
   bitset_word *src3p = ABITSET_WORDS (src3);
   bitset_word *dstp = ABITSET_WORDS (dst);
   bitset_windex size = dst->b.csize;
-  
+
   for (i = 0; i < size; i++, dstp++)
     {
       bitset_word tmp = (*src1p++ & *src2p++) | *src3p++;
-      
+
       if (*dstp != tmp)
 	{
-	  changed = 1;
+	  changed = true;
 	  *dstp = tmp;
 	}
     }
@@ -703,46 +613,38 @@ abitset_and_or_cmp (dst, src1, src2, src3)
 
 
 static void
-abitset_andn_or (dst, src1, src2, src3)
-     bitset dst;
-     bitset src1;
-     bitset src2;
-     bitset src3;
+abitset_andn_or (bitset dst, bitset src1, bitset src2, bitset src3)
 {
-  unsigned int i;
+  bitset_windex i;
   bitset_word *src1p = ABITSET_WORDS (src1);
   bitset_word *src2p = ABITSET_WORDS (src2);
   bitset_word *src3p = ABITSET_WORDS (src3);
   bitset_word *dstp = ABITSET_WORDS (dst);
   bitset_windex size = dst->b.csize;
-  
+
   for (i = 0; i < size; i++)
       *dstp++ = (*src1p++ & ~(*src2p++)) | *src3p++;
 }
 
 
-static int
-abitset_andn_or_cmp (dst, src1, src2, src3)
-     bitset dst;
-     bitset src1;
-     bitset src2;
-     bitset src3;
+static bool
+abitset_andn_or_cmp (bitset dst, bitset src1, bitset src2, bitset src3)
 {
-  unsigned int i;
-  int changed = 0;
+  bitset_windex i;
+  bool changed = false;
   bitset_word *src1p = ABITSET_WORDS (src1);
   bitset_word *src2p = ABITSET_WORDS (src2);
   bitset_word *src3p = ABITSET_WORDS (src3);
   bitset_word *dstp = ABITSET_WORDS (dst);
   bitset_windex size = dst->b.csize;
-  
+
   for (i = 0; i < size; i++, dstp++)
     {
       bitset_word tmp = (*src1p++ & ~(*src2p++)) | *src3p++;
-      
+
       if (*dstp != tmp)
 	{
-	  changed = 1;
+	  changed = true;
 	  *dstp = tmp;
 	}
     }
@@ -751,46 +653,38 @@ abitset_andn_or_cmp (dst, src1, src2, src3)
 
 
 static void
-abitset_or_and (dst, src1, src2, src3)
-     bitset dst;
-     bitset src1;
-     bitset src2;
-     bitset src3;
+abitset_or_and (bitset dst, bitset src1, bitset src2, bitset src3)
 {
-  unsigned int i;
+  bitset_windex i;
   bitset_word *src1p = ABITSET_WORDS (src1);
   bitset_word *src2p = ABITSET_WORDS (src2);
   bitset_word *src3p = ABITSET_WORDS (src3);
   bitset_word *dstp = ABITSET_WORDS (dst);
   bitset_windex size = dst->b.csize;
-  
+
   for (i = 0; i < size; i++)
       *dstp++ = (*src1p++ | *src2p++) & *src3p++;
 }
 
 
-static int
-abitset_or_and_cmp (dst, src1, src2, src3)
-     bitset dst;
-     bitset src1;
-     bitset src2;
-     bitset src3;
+static bool
+abitset_or_and_cmp (bitset dst, bitset src1, bitset src2, bitset src3)
 {
-  unsigned int i;
-  int changed = 0;
+  bitset_windex i;
+  bool changed = false;
   bitset_word *src1p = ABITSET_WORDS (src1);
   bitset_word *src2p = ABITSET_WORDS (src2);
   bitset_word *src3p = ABITSET_WORDS (src3);
   bitset_word *dstp = ABITSET_WORDS (dst);
   bitset_windex size = dst->b.csize;
-  
+
   for (i = 0; i < size; i++, dstp++)
     {
       bitset_word tmp = (*src1p++ | *src2p++) & *src3p++;
-      
+
       if (*dstp != tmp)
 	{
-	  changed = 1;
+	  changed = true;
 	  *dstp = tmp;
 	}
     }
@@ -798,10 +692,8 @@ abitset_or_and_cmp (dst, src1, src2, src3)
 }
 
 
-void
-abitset_copy (dst, src)
-     bitset dst;
-     bitset src;
+static void
+abitset_copy (bitset dst, bitset src)
 {
   if (BITSET_COMPATIBLE_ (dst, src))
       abitset_copy1 (dst, src);
@@ -816,7 +708,8 @@ struct bitset_vtable abitset_small_vtable = {
   abitset_reset,
   bitset_toggle_,
   abitset_test,
-  abitset_size,
+  abitset_resize,
+  bitset_size_,
   bitset_count_,
   abitset_empty_p,
   abitset_ones,
@@ -853,7 +746,8 @@ struct bitset_vtable abitset_vtable = {
   abitset_reset,
   bitset_toggle_,
   abitset_test,
-  abitset_size,
+  abitset_resize,
+  bitset_size_,
   bitset_count_,
   abitset_empty_p,
   abitset_ones,
@@ -884,27 +778,37 @@ struct bitset_vtable abitset_vtable = {
 };
 
 
-int
-abitset_bytes (n_bits)
-     bitset_bindex n_bits;
+size_t
+abitset_bytes (bitset_bindex n_bits)
 {
-  unsigned int bytes, size;
+  bitset_windex size;
+  size_t bytes;
+  size_t header_size = offsetof (union bitset_union, a.words);
+  struct bitset_align_struct { char a; union bitset_union b; };
+  size_t bitset_alignment = offsetof (struct bitset_align_struct, b);
 
   size = ABITSET_N_WORDS (n_bits);
-  bytes = size * sizeof (bitset_word);
-  return sizeof (struct bitset_struct) + bytes - sizeof (bitset_word);
+  bytes = header_size + size * sizeof (bitset_word);
+
+  /* Align the size properly for a vector of abitset objects.  */
+  if (header_size % bitset_alignment != 0
+      || sizeof (bitset_word) % bitset_alignment != 0)
+    {
+      bytes += bitset_alignment - 1;
+      bytes -= bytes % bitset_alignment;
+    }
+
+  return bytes;
 }
 
 
 bitset
-abitset_init (bset, n_bits)
-     bitset bset;
-     bitset_bindex n_bits;
+abitset_init (bitset bset, bitset_bindex n_bits)
 {
   bitset_windex size;
 
   size = ABITSET_N_WORDS (n_bits);
-  ABITSET_N_BITS (bset) = n_bits;
+  BITSET_NBITS_ (bset) = n_bits;
 
   /* Use optimized routines if bitset fits within a single word.
      There is probably little merit if using caching since