1 /* Licensed under LGPLv2+ - see LICENSE file for details */
2 #include <ccan/htable/htable.h>
3 #include <ccan/compiler/compiler.h>
11 /* We use 0x1 as deleted marker. */
12 #define HTABLE_DELETED (0x1)
14 static void *htable_default_alloc(struct htable *ht, size_t len)
16 return calloc(len, 1);
19 static void htable_default_free(struct htable *ht, void *p)
24 static void *(*htable_alloc)(struct htable *, size_t) = htable_default_alloc;
25 static void (*htable_free)(struct htable *, void *) = htable_default_free;
27 void htable_set_allocator(void *(*alloc)(struct htable *, size_t len),
28 void (*free)(struct htable *, void *p))
31 alloc = htable_default_alloc;
33 free = htable_default_free;
38 /* We clear out the bits which are always the same, and put metadata there. */
39 static inline uintptr_t get_extra_ptr_bits(const struct htable *ht,
42 return e & ht->common_mask;
45 static inline void *get_raw_ptr(const struct htable *ht, uintptr_t e)
47 return (void *)((e & ~ht->common_mask) | ht->common_bits);
50 static inline uintptr_t make_hval(const struct htable *ht,
51 const void *p, uintptr_t bits)
53 return ((uintptr_t)p & ~ht->common_mask) | bits;
56 static inline bool entry_is_valid(uintptr_t e)
58 return e > HTABLE_DELETED;
61 /* We use 0 to mean we don't have a perfect bit, otherwise it's
63 static inline uintptr_t ht_perfect_mask(const struct htable *ht)
65 if (ht->perfect_bitnum > 0)
66 return (uintptr_t)1 << (ht->perfect_bitnum - 1);
70 static inline uintptr_t get_hash_ptr_bits(const struct htable *ht,
73 /* Shuffling the extra bits (as specified in mask) down the
74 * end is quite expensive. But the lower bits are redundant, so
75 * we fold the value first. */
76 return (hash ^ (hash >> ht->bits))
77 & ht->common_mask & ~ht_perfect_mask(ht);
80 void htable_init(struct htable *ht,
81 size_t (*rehash)(const void *elem, void *priv), void *priv)
83 struct htable empty = HTABLE_INITIALIZER(empty, NULL, NULL);
87 ht->table = &ht->common_bits;
90 static inline size_t ht_max(const struct htable *ht)
92 return ((size_t)3 << ht->bits) / 4;
95 static inline size_t ht_max_with_deleted(const struct htable *ht)
97 return ((size_t)9 << ht->bits) / 10;
100 bool htable_init_sized(struct htable *ht,
101 size_t (*rehash)(const void *, void *),
102 void *priv, size_t expect)
104 htable_init(ht, rehash, priv);
106 /* Don't go insane with sizing. */
107 for (ht->bits = 1; ((size_t)3 << ht->bits) / 4 < expect; ht->bits++) {
112 ht->table = htable_alloc(ht, sizeof(size_t) << ht->bits);
114 ht->table = &ht->common_bits;
117 (void)htable_debug(ht, HTABLE_LOC);
121 void htable_clear(struct htable *ht)
123 if (ht->table != &ht->common_bits)
124 htable_free(ht, (void *)ht->table);
125 htable_init(ht, ht->rehash, ht->priv);
128 bool htable_copy_(struct htable *dst, const struct htable *src)
130 uintptr_t *htable = htable_alloc(dst, sizeof(size_t) << src->bits);
137 memcpy(dst->table, src->table, sizeof(size_t) << src->bits);
141 static size_t hash_bucket(const struct htable *ht, size_t h)
143 return h & ((1 << ht->bits)-1);
146 static void *htable_val(const struct htable *ht,
147 struct htable_iter *i, size_t hash, uintptr_t perfect)
149 uintptr_t h2 = get_hash_ptr_bits(ht, hash) | perfect;
151 while (ht->table[i->off]) {
152 if (ht->table[i->off] != HTABLE_DELETED) {
153 if (get_extra_ptr_bits(ht, ht->table[i->off]) == h2)
154 return get_raw_ptr(ht, ht->table[i->off]);
156 i->off = (i->off + 1) & ((1 << ht->bits)-1);
162 void *htable_firstval_(const struct htable *ht,
163 struct htable_iter *i, size_t hash)
165 i->off = hash_bucket(ht, hash);
166 return htable_val(ht, i, hash, ht_perfect_mask(ht));
169 void *htable_nextval_(const struct htable *ht,
170 struct htable_iter *i, size_t hash)
172 i->off = (i->off + 1) & ((1 << ht->bits)-1);
173 return htable_val(ht, i, hash, 0);
176 void *htable_first_(const struct htable *ht, struct htable_iter *i)
178 for (i->off = 0; i->off < (size_t)1 << ht->bits; i->off++) {
179 if (entry_is_valid(ht->table[i->off]))
180 return get_raw_ptr(ht, ht->table[i->off]);
185 void *htable_next_(const struct htable *ht, struct htable_iter *i)
187 for (i->off++; i->off < (size_t)1 << ht->bits; i->off++) {
188 if (entry_is_valid(ht->table[i->off]))
189 return get_raw_ptr(ht, ht->table[i->off]);
194 void *htable_prev_(const struct htable *ht, struct htable_iter *i)
200 if (entry_is_valid(ht->table[i->off]))
201 return get_raw_ptr(ht, ht->table[i->off]);
205 /* This does not expand the hash table, that's up to caller. */
206 static void ht_add(struct htable *ht, const void *new, size_t h)
209 uintptr_t perfect = ht_perfect_mask(ht);
211 i = hash_bucket(ht, h);
213 while (entry_is_valid(ht->table[i])) {
215 i = (i + 1) & ((1 << ht->bits)-1);
217 ht->table[i] = make_hval(ht, new, get_hash_ptr_bits(ht, h)|perfect);
220 static COLD bool double_table(struct htable *ht)
223 size_t oldnum = (size_t)1 << ht->bits;
224 uintptr_t *oldtable, e;
226 oldtable = ht->table;
227 ht->table = htable_alloc(ht, sizeof(size_t) << (ht->bits+1));
229 ht->table = oldtable;
234 /* If we lost our "perfect bit", get it back now. */
235 if (ht->perfect_bitnum == 0 && ht->common_mask) {
236 for (i = 0; i < sizeof(ht->common_mask) * CHAR_BIT; i++) {
237 if (ht->common_mask & ((size_t)1 << i)) {
238 ht->perfect_bitnum = i + 1;
244 if (oldtable != &ht->common_bits) {
245 for (i = 0; i < oldnum; i++) {
246 if (entry_is_valid(e = oldtable[i])) {
247 void *p = get_raw_ptr(ht, e);
248 ht_add(ht, p, ht->rehash(p, ht->priv));
251 htable_free(ht, oldtable);
255 (void)htable_debug(ht, HTABLE_LOC);
259 static COLD void rehash_table(struct htable *ht)
264 /* Beware wrap cases: we need to start from first empty bucket. */
265 for (start = 0; ht->table[start]; start++);
267 for (i = 0; i < (size_t)1 << ht->bits; i++) {
268 size_t h = (i + start) & ((1 << ht->bits)-1);
272 if (e == HTABLE_DELETED)
274 else if (!(e & ht_perfect_mask(ht))) {
275 void *p = get_raw_ptr(ht, e);
277 ht_add(ht, p, ht->rehash(p, ht->priv));
281 (void)htable_debug(ht, HTABLE_LOC);
284 /* We stole some bits, now we need to put them back... */
285 static COLD void update_common(struct htable *ht, const void *p)
288 uintptr_t maskdiff, bitsdiff;
290 if (ht->elems == 0) {
291 /* Always reveal one bit of the pointer in the bucket,
292 * so it's not zero or HTABLE_DELETED (1), even if
293 * hash happens to be 0. Assumes (void *)1 is not a
295 for (i = sizeof(uintptr_t)*CHAR_BIT - 1; i > 0; i--) {
296 if ((uintptr_t)p & ((uintptr_t)1 << i))
300 ht->common_mask = ~((uintptr_t)1 << i);
301 ht->common_bits = ((uintptr_t)p & ht->common_mask);
302 ht->perfect_bitnum = 1;
303 (void)htable_debug(ht, HTABLE_LOC);
307 /* Find bits which are unequal to old common set. */
308 maskdiff = ht->common_bits ^ ((uintptr_t)p & ht->common_mask);
310 /* These are the bits which go there in existing entries. */
311 bitsdiff = ht->common_bits & maskdiff;
313 for (i = 0; i < (size_t)1 << ht->bits; i++) {
314 if (!entry_is_valid(ht->table[i]))
316 /* Clear the bits no longer in the mask, set them as
318 ht->table[i] &= ~maskdiff;
319 ht->table[i] |= bitsdiff;
322 /* Take away those bits from our mask, bits and perfect bit. */
323 ht->common_mask &= ~maskdiff;
324 ht->common_bits &= ~maskdiff;
325 if (ht_perfect_mask(ht) & maskdiff)
326 ht->perfect_bitnum = 0;
327 (void)htable_debug(ht, HTABLE_LOC);
330 bool htable_add_(struct htable *ht, size_t hash, const void *p)
332 if (ht->elems+1 > ht_max(ht) && !double_table(ht))
334 if (ht->elems+1 + ht->deleted > ht_max_with_deleted(ht))
337 if (((uintptr_t)p & ht->common_mask) != ht->common_bits)
338 update_common(ht, p);
345 bool htable_del_(struct htable *ht, size_t h, const void *p)
347 struct htable_iter i;
350 for (c = htable_firstval(ht,&i,h); c; c = htable_nextval(ht,&i,h)) {
352 htable_delval(ht, &i);
359 void htable_delval_(struct htable *ht, struct htable_iter *i)
361 assert(i->off < (size_t)1 << ht->bits);
362 assert(entry_is_valid(ht->table[i->off]));
365 ht->table[i->off] = HTABLE_DELETED;
369 struct htable *htable_check(const struct htable *ht, const char *abortstr)
372 struct htable_iter i;
375 /* Use non-DEBUG versions here, to avoid infinite recursion with
376 * CCAN_HTABLE_DEBUG! */
377 for (p = htable_first_(ht, &i); p; p = htable_next_(ht, &i)) {
378 struct htable_iter i2;
380 size_t h = ht->rehash(p, ht->priv);
385 /* Open-code htable_get to avoid CCAN_HTABLE_DEBUG */
386 for (c = htable_firstval_(ht, &i2, h);
388 c = htable_nextval_(ht, &i2, h)) {
398 "%s: element %p in position %zu"
399 " cannot find itself\n",
406 if (n != ht->elems) {
409 "%s: found %zu elems, expected %zu\n",
410 abortstr, n, ht->elems);
416 return (struct htable *)ht;