* Sherlock Library -- Universal Hash Table
*
* (c) 2002 Martin Mares <mj@ucw.cz>
+ * (c) 2002 Robert Spalek <robert@ucw.cz>
+ *
+ * This software may be freely distributed and used according to the terms
+ * of the GNU Lesser General Public License.
*/
/*
*
* <always defined> init() -- initialize the hash table.
* HASH_WANT_CLEANUP cleanup() -- deallocate the hash table.
- * HASH_WANT_FIND node *find(key) -- find node with the specified
+ * HASH_WANT_FIND node *find(key) -- find first node with the specified
* key, return NULL if no such node exists.
+ * HASH_WANT_FIND_NEXT node *find(node *start) -- find next node with the
+ * specified key, return NULL if no such node exists.
* HASH_WANT_NEW node *new(key) -- create new node with given key.
* Doesn't check whether it already exists.
* HASH_WANT_LOOKUP node *lookup(key) -- find node with given key,
* ... and a couple of extra parameters:
*
* HASH_NOCASE string comparisons should be case-insensitive.
- * HASH_DEFAULT_SIZE=n initially, use hash table of `n' entries.
- * The `n' has to be a power of two.
+ * HASH_DEFAULT_SIZE=n initially, use hash table of approx. `n' entries.
* HASH_CONSERVE_SPACE use as little space as possible.
* HASH_FN_BITS=n The hash function gives only `n' significant bits.
* HASH_ATOMIC_TYPE=t Atomic values are of type `t' instead of int.
struct P(table) {
uns hash_size;
- uns hash_count, hash_max, hash_min, hash_hard_max, hash_mask;
+ uns hash_count, hash_max, hash_min, hash_hard_max;
P(bucket) **ht;
} P(table);
static void P(alloc_table) (void)
{
+ T.hash_size = nextprime(T.hash_size);
T.ht = xmalloc(sizeof(void *) * T.hash_size);
bzero(T.ht, sizeof(void *) * T.hash_size);
- T.hash_max = T.hash_size * 2;
- if (T.hash_max > T.hash_hard_max)
- T.hash_max = T.hash_hard_max;
- T.hash_min = T.hash_size / 4;
- T.hash_mask = T.hash_size - 1;
+ if (2*T.hash_size < T.hash_hard_max)
+ T.hash_max = 2*T.hash_size;
+ else
+ T.hash_max = ~0U;
+ if (T.hash_size/2 > HASH_DEFAULT_SIZE)
+ T.hash_min = T.hash_size/4;
+ else
+ T.hash_min = 0;
}
static void P(init) (void)
while (b)
{
nb = b->next;
- h = P(bucket_hash)(b) & T.hash_mask;
+ h = P(bucket_hash)(b) % T.hash_size;
b->next = newt[h];
newt[h] = b;
b = nb;
static P(node) * P(find) (HASH_KEY_DECL)
{
uns h0 = P(hash) (HASH_KEY( ));
- uns h = h0 & T.hash_mask;
+ uns h = h0 % T.hash_size;
P(bucket) *b;
for (b=T.ht[h]; b; b=b->next)
}
#endif
+#ifdef HASH_WANT_FIND_NEXT
+static P(node) * P(find_next) (P(node) *start)
+{
+#ifndef HASH_CONSERVE_SPACE
+ uns h0 = P(hash) (HASH_KEY(start->));
+#endif
+ P(bucket) *b = SKIP_BACK(P(bucket), n, start);
+
+ for (b=b->next; b; b=b->next)
+ {
+ if (
+#ifndef HASH_CONSERVE_SPACE
+ b->hash == h0 &&
+#endif
+ P(eq)(HASH_KEY(start->), HASH_KEY(b->n.)))
+ return &b->n;
+ }
+ return NULL;
+}
+#endif
+
#ifdef HASH_WANT_NEW
static P(node) * P(new) (HASH_KEY_DECL)
{
P(bucket) *b;
h0 = P(hash) (HASH_KEY( ));
- h = h0 & T.hash_mask;
+ h = h0 % T.hash_size;
b = P(alloc) (sizeof(struct P(bucket)) + HASH_EXTRA_SIZE(HASH_KEY( )));
b->next = T.ht[h];
T.ht[h] = b;
static P(node) * P(lookup) (HASH_KEY_DECL)
{
uns h0 = P(hash) (HASH_KEY( ));
- uns h = h0 & T.hash_mask;
+ uns h = h0 % T.hash_size;
P(bucket) *b;
for (b=T.ht[h]; b; b=b->next)
static int P(delete) (HASH_KEY_DECL)
{
uns h0 = P(hash) (HASH_KEY( ));
- uns h = h0 & T.hash_mask;
+ uns h = h0 % T.hash_size;
P(bucket) *b, **bb;
for (bb=&T.ht[h]; b=*bb; bb=&b->next)
{
P(bucket) *x = SKIP_BACK(struct P(bucket), n, n);
uns h0 = P(bucket_hash)(x);
- uns h = h0 & T.hash_mask;
+ uns h = h0 % T.hash_size;
P(bucket) *b, **bb;
for (bb=&T.ht[h]; (b=*bb) && b != x; bb=&b->next)
#undef HASH_WANT_CLEANUP
#undef HASH_WANT_DELETE
#undef HASH_WANT_FIND
+#undef HASH_WANT_FIND_NEXT
#undef HASH_WANT_LOOKUP
#undef HASH_WANT_NEW
#undef HASH_WANT_REMOVE