+/* Licensed under LGPLv2+ - see LICENSE file for details */
#include <ccan/htable/htable.h>
#include <ccan/compiler/compiler.h>
#include <stdint.h>
#include <stdlib.h>
+#include <limits.h>
#include <stdbool.h>
#include <assert.h>
-/* This means a struct htable takes at least 512 bytes / 1k (32/64 bits). */
-#define HTABLE_BASE_BITS 7
-
/* We use 0x1 as deleted marker. */
#define HTABLE_DELETED (0x1)
size_t elems, deleted, max, max_with_deleted;
/* These are the bits which are the same in all pointers. */
uintptr_t common_mask, common_bits;
+ uintptr_t perfect_bit;
uintptr_t *table;
};
/* Shuffling the extra bits (as specified in mask) down the
* end is quite expensive. But the lower bits are redundant, so
* we fold the value first. */
- return (hash ^ (hash >> ht->bits)) & ht->common_mask;
+ return (hash ^ (hash >> ht->bits))
+ & ht->common_mask & ~ht->perfect_bit;
}
struct htable *htable_new(size_t (*rehash)(const void *elem, void *priv),
{
struct htable *ht = malloc(sizeof(struct htable));
if (ht) {
- ht->bits = HTABLE_BASE_BITS;
+ ht->bits = 0;
ht->rehash = rehash;
ht->priv = priv;
ht->elems = 0;
ht->deleted = 0;
- ht->max = (1 << ht->bits) * 2 / 3;
- ht->max_with_deleted = (1 << ht->bits) * 4 / 5;
+ ht->max = 0;
+ ht->max_with_deleted = 0;
/* This guarantees we enter update_common first add. */
ht->common_mask = -1;
ht->common_bits = 0;
- ht->table = calloc(1 << ht->bits, sizeof(uintptr_t));
- if (!ht->table) {
- free(ht);
- ht = NULL;
- }
+ ht->perfect_bit = 0;
+ /* Dummy table until first insert. */
+ ht->table = &ht->perfect_bit;
}
return ht;
}
void htable_free(const struct htable *ht)
{
- free((void *)ht->table);
+ if (ht->table != &ht->perfect_bit)
+ free((void *)ht->table);
free((void *)ht);
}
}
static void *htable_val(const struct htable *ht,
- struct htable_iter *i, size_t hash)
+ struct htable_iter *i, size_t hash, uintptr_t perfect)
{
- uintptr_t h2 = get_hash_ptr_bits(ht, hash);
+ uintptr_t h2 = get_hash_ptr_bits(ht, hash) | perfect;
while (ht->table[i->off]) {
if (ht->table[i->off] != HTABLE_DELETED) {
return get_raw_ptr(ht, ht->table[i->off]);
}
i->off = (i->off + 1) & ((1 << ht->bits)-1);
+ h2 &= ~perfect;
}
return NULL;
}
struct htable_iter *i, size_t hash)
{
i->off = hash_bucket(ht, hash);
- return htable_val(ht, i, hash);
+ return htable_val(ht, i, hash, ht->perfect_bit);
}
void *htable_nextval(const struct htable *ht,
struct htable_iter *i, size_t hash)
{
i->off = (i->off + 1) & ((1 << ht->bits)-1);
- return htable_val(ht, i, hash);
+ return htable_val(ht, i, hash, 0);
}
void *htable_first(const struct htable *ht, struct htable_iter *i)
static void ht_add(struct htable *ht, const void *new, size_t h)
{
size_t i;
+ uintptr_t perfect = ht->perfect_bit;
i = hash_bucket(ht, h);
- while (entry_is_valid(ht->table[i]))
+ while (entry_is_valid(ht->table[i])) {
+ perfect = 0;
i = (i + 1) & ((1 << ht->bits)-1);
-
- ht->table[i] = make_hval(ht, new, get_hash_ptr_bits(ht, h));
+ }
+ ht->table[i] = make_hval(ht, new, get_hash_ptr_bits(ht, h)|perfect);
}
-static COLD_ATTRIBUTE bool double_table(struct htable *ht)
+static COLD bool double_table(struct htable *ht)
{
unsigned int i;
size_t oldnum = (size_t)1 << ht->bits;
return false;
}
ht->bits++;
- ht->max *= 2;
- ht->max_with_deleted *= 2;
+ ht->max = ((size_t)3 << ht->bits) / 4;
+ ht->max_with_deleted = ((size_t)9 << ht->bits) / 10;
+
+ /* If we lost our "perfect bit", get it back now. */
+ if (!ht->perfect_bit && ht->common_mask) {
+ for (i = 0; i < sizeof(ht->common_mask) * CHAR_BIT; i++) {
+ if (ht->common_mask & ((size_t)1 << i)) {
+ ht->perfect_bit = (size_t)1 << i;
+ break;
+ }
+ }
+ }
- for (i = 0; i < oldnum; i++) {
- if (entry_is_valid(e = oldtable[i])) {
- void *p = get_raw_ptr(ht, e);
- ht_add(ht, p, ht->rehash(p, ht->priv));
+ if (oldtable != &ht->perfect_bit) {
+ for (i = 0; i < oldnum; i++) {
+ if (entry_is_valid(e = oldtable[i])) {
+ void *p = get_raw_ptr(ht, e);
+ ht_add(ht, p, ht->rehash(p, ht->priv));
+ }
}
+ free(oldtable);
}
ht->deleted = 0;
- free(oldtable);
return true;
}
-static COLD_ATTRIBUTE void rehash_table(struct htable *ht)
+static COLD void rehash_table(struct htable *ht)
{
size_t start, i;
uintptr_t e;
e = ht->table[h];
if (!e)
continue;
- ht->table[h] = 0;
- if (e != HTABLE_DELETED) {
+ if (e == HTABLE_DELETED)
+ ht->table[h] = 0;
+ else if (!(e & ht->perfect_bit)) {
void *p = get_raw_ptr(ht, e);
+ ht->table[h] = 0;
ht_add(ht, p, ht->rehash(p, ht->priv));
}
}
}
/* We stole some bits, now we need to put them back... */
-static COLD_ATTRIBUTE void update_common(struct htable *ht, const void *p)
+static COLD void update_common(struct htable *ht, const void *p)
{
unsigned int i;
uintptr_t maskdiff, bitsdiff;
if (ht->elems == 0) {
ht->common_mask = -1;
ht->common_bits = (uintptr_t)p;
+ ht->perfect_bit = 1;
return;
}
ht->table[i] |= bitsdiff;
}
- /* Take away those bits from our mask and set. */
+ /* Take away those bits from our mask, bits and perfect bit. */
ht->common_mask &= ~maskdiff;
ht->common_bits &= ~maskdiff;
+ ht->perfect_bit &= ~maskdiff;
}
bool htable_add(struct htable *ht, size_t hash, const void *p)
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