X-Git-Url: http://git.ozlabs.org/?p=ccan;a=blobdiff_plain;f=ccan%2Fhtable%2Fhtable.c;h=b27d063f207000b65fbbdd14aed05f171c279d09;hp=48a734071fa93e1cca12a438c129c008ec0e72ee;hb=d615e534e870a911f11b7b88021242220ea053bf;hpb=6ceee26828dcb8bf1d607a8221f0d9f8261d448b diff --git a/ccan/htable/htable.c b/ccan/htable/htable.c index 48a73407..b27d063f 100644 --- a/ccan/htable/htable.c +++ b/ccan/htable/htable.c @@ -1,25 +1,39 @@ +/* Licensed under LGPLv2+ - see LICENSE file for details */ #include #include -#include #include +#include +#include #include #include - -/* This means a struct htable takes at least 512 bytes / 1k (32/64 bits). */ -#define HTABLE_BASE_BITS 7 +#include /* We use 0x1 as deleted marker. */ #define HTABLE_DELETED (0x1) -struct htable { - size_t (*rehash)(const void *elem, void *priv); - void *priv; - unsigned int bits; - 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 *table; -}; +static void *htable_default_alloc(struct htable *ht, size_t len) +{ + return calloc(len, 1); +} + +static void htable_default_free(struct htable *ht, void *p) +{ + free(p); +} + +static void *(*htable_alloc)(struct htable *, size_t) = htable_default_alloc; +static void (*htable_free)(struct htable *, void *) = htable_default_free; + +void htable_set_allocator(void *(*alloc)(struct htable *, size_t len), + void (*free)(struct htable *, void *p)) +{ + if (!alloc) + alloc = htable_default_alloc; + if (!free) + free = htable_default_free; + htable_alloc = alloc; + htable_free = free; +} /* We clear out the bits which are always the same, and put metadata there. */ static inline uintptr_t get_extra_ptr_bits(const struct htable *ht, @@ -44,43 +58,84 @@ static inline bool entry_is_valid(uintptr_t e) return e > HTABLE_DELETED; } +/* We use 0 to mean we don't have a perfect bit, otherwise it's + * bit n - 1 */ +static inline uintptr_t ht_perfect_mask(const struct htable *ht) +{ + if (ht->perfect_bitnum > 0) + return (uintptr_t)1 << (ht->perfect_bitnum - 1); + return 0; +} + static inline uintptr_t get_hash_ptr_bits(const struct htable *ht, size_t hash) { /* 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_mask(ht); } -struct htable *htable_new(size_t (*rehash)(const void *elem, void *priv), - void *priv) +void htable_init(struct htable *ht, + size_t (*rehash)(const void *elem, void *priv), void *priv) { - struct htable *ht = malloc(sizeof(struct htable)); - if (ht) { - ht->bits = HTABLE_BASE_BITS; - 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; - /* 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; - } + struct htable empty = HTABLE_INITIALIZER(empty, NULL, NULL); + *ht = empty; + ht->rehash = rehash; + ht->priv = priv; + ht->table = &ht->common_bits; +} + +static inline size_t ht_max(const struct htable *ht) +{ + return ((size_t)3 << ht->bits) / 4; +} + +static inline size_t ht_max_with_deleted(const struct htable *ht) +{ + return ((size_t)9 << ht->bits) / 10; +} + +bool htable_init_sized(struct htable *ht, + size_t (*rehash)(const void *, void *), + void *priv, size_t expect) +{ + htable_init(ht, rehash, priv); + + /* Don't go insane with sizing. */ + for (ht->bits = 1; ((size_t)3 << ht->bits) / 4 < expect; ht->bits++) { + if (ht->bits == 30) + break; } - return ht; + + ht->table = htable_alloc(ht, sizeof(size_t) << ht->bits); + if (!ht->table) { + ht->table = &ht->common_bits; + return false; + } + (void)htable_debug(ht, HTABLE_LOC); + return true; +} + +void htable_clear(struct htable *ht) +{ + if (ht->table != &ht->common_bits) + htable_free(ht, (void *)ht->table); + htable_init(ht, ht->rehash, ht->priv); } -void htable_free(const struct htable *ht) +bool htable_copy_(struct htable *dst, const struct htable *src) { - free((void *)ht->table); - free((void *)ht); + uintptr_t *htable = htable_alloc(dst, sizeof(size_t) << src->bits); + + if (!htable) + return false; + + *dst = *src; + dst->table = htable; + memcpy(dst->table, src->table, sizeof(size_t) << src->bits); + return true; } static size_t hash_bucket(const struct htable *ht, size_t h) @@ -89,9 +144,9 @@ static size_t hash_bucket(const struct htable *ht, size_t h) } 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) { @@ -99,25 +154,26 @@ static void *htable_val(const struct htable *ht, return get_raw_ptr(ht, ht->table[i->off]); } i->off = (i->off + 1) & ((1 << ht->bits)-1); + h2 &= ~perfect; } return NULL; } -void *htable_firstval(const struct htable *ht, - struct htable_iter *i, size_t hash) +void *htable_firstval_(const struct htable *ht, + 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_mask(ht)); } -void *htable_nextval(const struct htable *ht, - struct htable_iter *i, size_t hash) +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) +void *htable_first_(const struct htable *ht, struct htable_iter *i) { for (i->off = 0; i->off < (size_t)1 << ht->bits; i->off++) { if (entry_is_valid(ht->table[i->off])) @@ -126,7 +182,7 @@ void *htable_first(const struct htable *ht, struct htable_iter *i) return NULL; } -void *htable_next(const struct htable *ht, struct htable_iter *i) +void *htable_next_(const struct htable *ht, struct htable_iter *i) { for (i->off++; i->off < (size_t)1 << ht->bits; i->off++) { if (entry_is_valid(ht->table[i->off])) @@ -135,47 +191,72 @@ void *htable_next(const struct htable *ht, struct htable_iter *i) return NULL; } +void *htable_prev_(const struct htable *ht, struct htable_iter *i) +{ + for (;;) { + if (!i->off) + return NULL; + i->off --; + if (entry_is_valid(ht->table[i->off])) + return get_raw_ptr(ht, ht->table[i->off]); + } +} + /* This does not expand the hash table, that's up to caller. */ static void ht_add(struct htable *ht, const void *new, size_t h) { size_t i; + uintptr_t perfect = ht_perfect_mask(ht); 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; uintptr_t *oldtable, e; oldtable = ht->table; - ht->table = calloc(1 << (ht->bits+1), sizeof(size_t)); + ht->table = htable_alloc(ht, sizeof(size_t) << (ht->bits+1)); if (!ht->table) { ht->table = oldtable; return false; } ht->bits++; - ht->max *= 2; - ht->max_with_deleted *= 2; - 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 we lost our "perfect bit", get it back now. */ + if (ht->perfect_bitnum == 0 && ht->common_mask) { + for (i = 0; i < sizeof(ht->common_mask) * CHAR_BIT; i++) { + if (ht->common_mask & ((size_t)1 << i)) { + ht->perfect_bitnum = i + 1; + break; + } + } + } + + if (oldtable != &ht->common_bits) { + 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)); + } } + htable_free(ht, oldtable); } ht->deleted = 0; - free(oldtable); + + (void)htable_debug(ht, HTABLE_LOC); 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; @@ -188,24 +269,38 @@ static COLD_ATTRIBUTE void rehash_table(struct htable *ht) 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_mask(ht))) { void *p = get_raw_ptr(ht, e); + ht->table[h] = 0; ht_add(ht, p, ht->rehash(p, ht->priv)); } } ht->deleted = 0; + (void)htable_debug(ht, HTABLE_LOC); } /* 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; + /* 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_bitnum = 1; + (void)htable_debug(ht, HTABLE_LOC); return; } @@ -224,16 +319,19 @@ static COLD_ATTRIBUTE void update_common(struct htable *ht, const void *p) 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; + if (ht_perfect_mask(ht) & maskdiff) + ht->perfect_bitnum = 0; + (void)htable_debug(ht, HTABLE_LOC); } -bool htable_add(struct htable *ht, size_t hash, const void *p) +bool htable_add_(struct htable *ht, size_t hash, const void *p) { - if (ht->elems+1 > ht->max && !double_table(ht)) + if (ht->elems+1 > ht_max(ht) && !double_table(ht)) return false; - if (ht->elems+1 + ht->deleted > ht->max_with_deleted) + if (ht->elems+1 + ht->deleted > ht_max_with_deleted(ht)) rehash_table(ht); assert(p); if (((uintptr_t)p & ht->common_mask) != ht->common_bits) @@ -244,7 +342,7 @@ bool htable_add(struct htable *ht, size_t hash, const void *p) return true; } -bool htable_del(struct htable *ht, size_t h, const void *p) +bool htable_del_(struct htable *ht, size_t h, const void *p) { struct htable_iter i; void *c; @@ -258,7 +356,7 @@ bool htable_del(struct htable *ht, size_t h, const void *p) return false; } -void htable_delval(struct htable *ht, struct htable_iter *i) +void htable_delval_(struct htable *ht, struct htable_iter *i) { assert(i->off < (size_t)1 << ht->bits); assert(entry_is_valid(ht->table[i->off])); @@ -267,3 +365,53 @@ void htable_delval(struct htable *ht, struct htable_iter *i) ht->table[i->off] = HTABLE_DELETED; ht->deleted++; } + +struct htable *htable_check(const struct htable *ht, const char *abortstr) +{ + void *p; + struct htable_iter i; + size_t n = 0; + + /* Use non-DEBUG versions here, to avoid infinite recursion with + * CCAN_HTABLE_DEBUG! */ + for (p = htable_first_(ht, &i); p; p = htable_next_(ht, &i)) { + struct htable_iter i2; + void *c; + size_t h = ht->rehash(p, ht->priv); + bool found = false; + + n++; + + /* Open-code htable_get to avoid CCAN_HTABLE_DEBUG */ + for (c = htable_firstval_(ht, &i2, h); + c; + c = htable_nextval_(ht, &i2, h)) { + if (c == p) { + found = true; + break; + } + } + + if (!found) { + if (abortstr) { + fprintf(stderr, + "%s: element %p in position %zu" + " cannot find itself\n", + abortstr, p, i.off); + abort(); + } + return NULL; + } + } + if (n != ht->elems) { + if (abortstr) { + fprintf(stderr, + "%s: found %zu elems, expected %zu\n", + abortstr, n, ht->elems); + abort(); + } + return NULL; + } + + return (struct htable *)ht; +}