Include <stddef.h>, for offsetof.

(abitset_bytes): Return a size that is aligned
properly for vectors of objects.  Do not assume that adding a
header size to a multiple of a word size yields a value that is
properly aligned for the whole union.

(abitset_ones, abitset_zero, abitset_empty_p, abitset_copy1,
abitset_not, abitset_equal_p, abitset_subset_p, abitset_disjoint_p,
abitset_and, abitset_and_cmp, abitset_andn, abitset_andn_cmp,
abitset_or, abitset_or_cmp, abitset_xor, abitset_xor_cmp,
abitset_and_or, abitset_and_or_cmp, abitset_andn_or,
abitset_andn_or_cmp, abitset_or_and, abitset_or_and_cmp,
abitset_copy): Supply prototype decls, to improve the type-checking
that GCC can do.

(struct abitset_struct, abitset, struct bitset_struct): Remove.

diff --git a/lib/abitset.c b/lib/abitset.c
index c9052f9..05f3717 100644 (file)
--- a/lib/abitset.c
+++ b/lib/abitset.c
@@ -22,27 +22,37 @@
 #endif
 
 #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
-{
-  bitset_bindex 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 void abitset_ones PARAMS ((bitset));
+static void abitset_zero PARAMS ((bitset));
+static int abitset_empty_p PARAMS ((bitset));
+static void abitset_copy1 PARAMS ((bitset, bitset));
+static void abitset_not PARAMS ((bitset, bitset));
+static int abitset_equal_p PARAMS ((bitset, bitset));
+static int abitset_subset_p PARAMS ((bitset, bitset));
+static int abitset_disjoint_p PARAMS ((bitset, bitset));
+static void abitset_and PARAMS ((bitset, bitset, bitset));
+static int abitset_and_cmp PARAMS ((bitset, bitset, bitset));
+static void abitset_andn PARAMS ((bitset, bitset, bitset));
+static int abitset_andn_cmp PARAMS ((bitset, bitset, bitset));
+static void abitset_or PARAMS ((bitset, bitset, bitset));
+static int abitset_or_cmp PARAMS ((bitset, bitset, bitset));
+static void abitset_xor PARAMS ((bitset, bitset, bitset));
+static int abitset_xor_cmp PARAMS ((bitset, bitset, bitset));
+static void abitset_and_or PARAMS ((bitset, bitset, bitset, bitset));
+static int abitset_and_or_cmp PARAMS ((bitset, bitset, bitset, bitset));
+static void abitset_andn_or PARAMS ((bitset, bitset, bitset, bitset));
+static int abitset_andn_or_cmp PARAMS ((bitset, bitset, bitset, bitset));
+static void abitset_or_and PARAMS ((bitset, bitset, bitset, bitset));
+static int abitset_or_and_cmp PARAMS ((bitset, bitset, bitset, bitset));
+static void abitset_copy PARAMS ((bitset, bitset));
 
 static bitset_bindex abitset_small_list PARAMS ((bitset, bitset_bindex *,
                                                 bitset_bindex,
@@ -799,7 +809,7 @@ abitset_or_and_cmp (dst, src1, src2, src3)
 }
 
 
-void
+static void
 abitset_copy (dst, src)
      bitset dst;
      bitset src;
@@ -891,10 +901,22 @@ abitset_bytes (n_bits)
 {
   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;
 }