--- /dev/null
+#define CCAN_HTABLE_DEBUG
+#include <ccan/htable/htable.h>
+#include <ccan/htable/htable.c>
+#include <ccan/tap/tap.h>
+#include <stdbool.h>
+#include <string.h>
+
+#define NUM_BITS 7
+#define NUM_VALS (1 << NUM_BITS)
+
+static void *bad_pointer;
+
+/* We use the number divided by two as the hash (for lots of
+ collisions), plus set all the higher bits so we can detect if they
+ don't get masked out. */
+static size_t hash(const void *elem, void *unused UNNEEDED)
+{
+ size_t h;
+
+ /* With CCAN_HTABLE_DEBUG enabled, it will try to hash each element,
+ * including this one... */
+ if (elem == bad_pointer)
+ return 0;
+
+ h = *(uint64_t *)elem / 2;
+ h |= -1UL << NUM_BITS;
+ return h;
+}
+
+static bool objcmp(const void *htelem, void *cmpdata)
+{
+ return *(uint64_t *)htelem == *(uint64_t *)cmpdata;
+}
+
+static void add_vals(struct htable *ht,
+ const uint64_t val[],
+ unsigned int off, unsigned int num)
+{
+ uint64_t i;
+
+ for (i = off; i < off+num; i++) {
+ if (htable_get(ht, hash(&i, NULL), objcmp, &i)) {
+ fail("%llu already in hash", (long long)i);
+ return;
+ }
+ htable_add(ht, hash(&val[i], NULL), &val[i]);
+ if (htable_get(ht, hash(&i, NULL), objcmp, &i) != &val[i]) {
+ fail("%llu not added to hash", (long long)i);
+ return;
+ }
+ }
+ pass("Added %llu numbers to hash", (long long)i);
+}
+
+#if 0
+static void refill_vals(struct htable *ht,
+ const uint64_t val[], unsigned int num)
+{
+ uint64_t i;
+
+ for (i = 0; i < num; i++) {
+ if (htable_get(ht, hash(&i, NULL), objcmp, &i))
+ continue;
+ htable_add(ht, hash(&val[i], NULL), &val[i]);
+ }
+}
+#endif
+
+static void find_vals(struct htable *ht,
+ const uint64_t val[], unsigned int num)
+{
+ uint64_t i;
+
+ for (i = 0; i < num; i++) {
+ if (htable_get(ht, hash(&i, NULL), objcmp, &i) != &val[i]) {
+ fail("%llu not found in hash", (long long)i);
+ return;
+ }
+ }
+ pass("Found %llu numbers in hash", (long long)i);
+}
+
+static void del_vals(struct htable *ht,
+ const uint64_t val[], unsigned int num)
+{
+ uint64_t i;
+
+ for (i = 0; i < num; i++) {
+ if (!htable_del(ht, hash(&val[i], NULL), &val[i])) {
+ fail("%llu not deleted from hash", (long long)i);
+ return;
+ }
+ }
+ pass("Deleted %llu numbers in hash", (long long)i);
+}
+
+static bool check_mask(struct htable *ht, uint64_t val[], unsigned num)
+{
+ uint64_t i;
+
+ for (i = 0; i < num; i++) {
+ if (((uintptr_t)&val[i] & ht->common_mask) != ht->common_bits)
+ return false;
+ }
+ return true;
+}
+
+int main(void)
+{
+ unsigned int i, weight;
+ uintptr_t perfect_bit;
+ struct htable ht;
+ uint64_t val[NUM_VALS];
+ uint64_t dne;
+ void *p;
+ struct htable_iter iter;
+
+ plan_tests(36);
+ for (i = 0; i < NUM_VALS; i++)
+ val[i] = i;
+ dne = i;
+
+ htable_init(&ht, hash, NULL);
+ ok1(ht.max == 0);
+ ok1(ht.bits == 0);
+
+ /* We cannot find an entry which doesn't exist. */
+ ok1(!htable_get(&ht, hash(&dne, NULL), objcmp, &dne));
+
+ /* This should increase it once. */
+ add_vals(&ht, val, 0, 1);
+ ok1(ht.bits == 1);
+ ok1(ht.max == 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));
+
+ /* This should increase it again. */
+ add_vals(&ht, val, 1, 1);
+ ok1(ht.bits == 2);
+ ok1(ht.max == 3);
+
+ /* Mask should be set. */
+ ok1(ht.common_mask != 0);
+ ok1(ht.common_mask != -1);
+ ok1(check_mask(&ht, val, 2));
+
+ /* Now do the rest. */
+ add_vals(&ht, val, 2, NUM_VALS - 2);
+
+ /* Find all. */
+ find_vals(&ht, val, NUM_VALS);
+ ok1(!htable_get(&ht, hash(&dne, NULL), objcmp, &dne));
+
+ /* Walk once, should get them all. */
+ i = 0;
+ for (p = htable_first(&ht,&iter); p; p = htable_next(&ht, &iter))
+ i++;
+ ok1(i == NUM_VALS);
+
+ i = 0;
+ for (p = htable_prev(&ht, &iter); p; p = htable_prev(&ht, &iter))
+ i++;
+ ok1(i == NUM_VALS);
+
+ /* Delete all. */
+ del_vals(&ht, val, NUM_VALS);
+ ok1(!htable_get(&ht, hash(&val[0], NULL), objcmp, &val[0]));
+
+ /* Worst case, a "pointer" which doesn't have any matching bits. */
+ bad_pointer = (void *)~(uintptr_t)&val[NUM_VALS-1];
+ htable_add(&ht, 0, bad_pointer);
+ htable_add(&ht, hash(&val[NUM_VALS-1], NULL), &val[NUM_VALS-1]);
+ ok1(ht.common_mask == 0);
+ ok1(ht.common_bits == 0);
+ /* Get rid of bogus pointer before we trip over it! */
+ htable_del(&ht, 0, bad_pointer);
+
+ /* Add the rest. */
+ add_vals(&ht, val, 0, NUM_VALS-1);
+
+ /* Check we can find them all. */
+ find_vals(&ht, val, NUM_VALS);
+ ok1(!htable_get(&ht, hash(&dne, NULL), objcmp, &dne));
+
+ /* Corner cases: wipe out the perfect bit using bogus pointer. */
+ htable_clear(&ht);
+ htable_add(&ht, hash(&val[NUM_VALS-1], NULL), &val[NUM_VALS-1]);
+ ok1(ht.perfect_bit);
+ perfect_bit = ht.perfect_bit;
+ bad_pointer = (void *)((uintptr_t)&val[NUM_VALS-1] | perfect_bit);
+ htable_add(&ht, 0, bad_pointer);
+ ok1(ht.perfect_bit == 0);
+ htable_del(&ht, 0, bad_pointer);
+
+ /* Enlarging should restore it... */
+ add_vals(&ht, val, 0, NUM_VALS-1);
+
+ ok1(ht.perfect_bit != 0);
+ htable_clear(&ht);
+
+ ok1(htable_init_sized(&ht, hash, NULL, 1024));
+ ok1(ht.max >= 1024);
+ htable_clear(&ht);
+
+ ok1(htable_init_sized(&ht, hash, NULL, 1023));
+ ok1(ht.max >= 1023);
+ htable_clear(&ht);
+
+ ok1(htable_init_sized(&ht, hash, NULL, 1025));
+ ok1(ht.max >= 1025);
+ htable_clear(&ht);
+
+ return exit_status();
+}