uintptr_t maskdiff, bitsdiff;
if (ht->elems == 0) {
- ht->common_mask = -1;
- ht->common_bits = (uintptr_t)p;
+ /* Always reveal one bit of the pointer in the bucket,
+ * so it's not zero or HTABLE_DELETED (1), even if
+ * hash happens to be 0. Assumes (void *)1 is not a
+ * valid pointer. */
+ for (i = sizeof(uintptr_t)*CHAR_BIT - 1; i > 0; i--) {
+ if ((uintptr_t)p & ((uintptr_t)1 << i))
+ break;
+ }
+
+ ht->common_mask = ~((uintptr_t)1 << i);
+ ht->common_bits = ((uintptr_t)p & ht->common_mask);
ht->perfect_bit = 1;
return;
}
--- /dev/null
+#include <ccan/htable/htable.h>
+#include <ccan/htable/htable.c>
+#include <ccan/tap/tap.h>
+#include <stdbool.h>
+
+struct data {
+ size_t key;
+};
+
+/* Hash is simply key itself. */
+static size_t hash(const void *e, void *unused)
+{
+ struct data *d = (struct data *)e;
+
+ return d->key;
+}
+
+static bool eq(const void *e, void *k)
+{
+ struct data *d = (struct data *)e;
+ size_t *key = (size_t *)k;
+
+ return (d->key == *key);
+}
+
+int main(void)
+{
+ struct htable table;
+ struct data *d0, *d1;
+
+ plan_tests(6);
+
+ d1 = malloc(sizeof(struct data));
+ d1->key = 1;
+ d0 = malloc(sizeof(struct data));
+ d0->key = 0;
+
+ htable_init(&table, hash, NULL);
+
+ htable_add(&table, d0->key, d0);
+ htable_add(&table, d1->key, d1);
+
+ ok1(table.elems == 2);
+ ok1(htable_get(&table, 1, eq, &d1->key) == d1);
+ ok1(htable_get(&table, 0, eq, &d0->key) == d0);
+ htable_clear(&table);
+
+ /* Now add in reverse order, should still be OK. */
+ htable_add(&table, d1->key, d1);
+ htable_add(&table, d0->key, d0);
+
+ ok1(table.elems == 2);
+ ok1(htable_get(&table, 1, eq, &d1->key) == d1);
+ ok1(htable_get(&table, 0, eq, &d0->key) == d0);
+ htable_clear(&table);
+
+ free(d0);
+ free(d1);
+ return exit_status();
+}
+
int main(int argc, char *argv[])
{
- unsigned int i;
+ unsigned int i, weight;
uintptr_t perfect_bit;
struct htable ht;
uint64_t val[NUM_VALS];
add_vals(&ht, val, 0, 1);
ok1(ht.bits == 1);
ok1(ht.max == 1);
- ok1(ht.common_mask == -1);
+ weight = 0;
+ for (i = 0; i < sizeof(ht.common_mask) * CHAR_BIT; i++) {
+ if (ht.common_mask & ((uintptr_t)1 << i)) {
+ weight++;
+ }
+ }
+ /* Only one bit should be clear. */
+ ok1(weight == i-1);
/* Mask should be set. */
ok1(check_mask(&ht, val, 1));