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Diffstat (limited to 'src/basic/hashmap.c')
| -rw-r--r-- | src/basic/hashmap.c | 1854 |
1 files changed, 1854 insertions, 0 deletions
diff --git a/src/basic/hashmap.c b/src/basic/hashmap.c new file mode 100644 index 0000000000..20d599d04b --- /dev/null +++ b/src/basic/hashmap.c @@ -0,0 +1,1854 @@ +/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/ + +/*** + This file is part of systemd. + + Copyright 2010 Lennart Poettering + Copyright 2014 Michal Schmidt + + systemd is free software; you can redistribute it and/or modify it + under the terms of the GNU Lesser General Public License as published by + the Free Software Foundation; either version 2.1 of the License, or + (at your option) any later version. + + systemd is distributed in the hope that it will be useful, but + WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public License + along with systemd; If not, see <http://www.gnu.org/licenses/>. +***/ + +#include <stdlib.h> +#include <errno.h> + +#include "util.h" +#include "hashmap.h" +#include "set.h" +#include "macro.h" +#include "siphash24.h" +#include "strv.h" +#include "mempool.h" +#include "random-util.h" + +#ifdef ENABLE_DEBUG_HASHMAP +#include "list.h" +#endif + +/* + * Implementation of hashmaps. + * Addressing: open + * - uses less RAM compared to closed addressing (chaining), because + * our entries are small (especially in Sets, which tend to contain + * the majority of entries in systemd). + * Collision resolution: Robin Hood + * - tends to equalize displacement of entries from their optimal buckets. + * Probe sequence: linear + * - though theoretically worse than random probing/uniform hashing/double + * hashing, it is good for cache locality. + * + * References: + * Celis, P. 1986. Robin Hood Hashing. + * Ph.D. Dissertation. University of Waterloo, Waterloo, Ont., Canada, Canada. + * https://cs.uwaterloo.ca/research/tr/1986/CS-86-14.pdf + * - The results are derived for random probing. Suggests deletion with + * tombstones and two mean-centered search methods. None of that works + * well for linear probing. + * + * Janson, S. 2005. Individual displacements for linear probing hashing with different insertion policies. + * ACM Trans. Algorithms 1, 2 (October 2005), 177-213. + * DOI=10.1145/1103963.1103964 http://doi.acm.org/10.1145/1103963.1103964 + * http://www.math.uu.se/~svante/papers/sj157.pdf + * - Applies to Robin Hood with linear probing. Contains remarks on + * the unsuitability of mean-centered search with linear probing. + * + * Viola, A. 2005. Exact distribution of individual displacements in linear probing hashing. + * ACM Trans. Algorithms 1, 2 (October 2005), 214-242. + * DOI=10.1145/1103963.1103965 http://doi.acm.org/10.1145/1103963.1103965 + * - Similar to Janson. Note that Viola writes about C_{m,n} (number of probes + * in a successful search), and Janson writes about displacement. C = d + 1. + * + * Goossaert, E. 2013. Robin Hood hashing: backward shift deletion. + * http://codecapsule.com/2013/11/17/robin-hood-hashing-backward-shift-deletion/ + * - Explanation of backward shift deletion with pictures. + * + * Khuong, P. 2013. The Other Robin Hood Hashing. + * http://www.pvk.ca/Blog/2013/11/26/the-other-robin-hood-hashing/ + * - Short summary of random vs. linear probing, and tombstones vs. backward shift. + */ + +/* + * XXX Ideas for improvement: + * For unordered hashmaps, randomize iteration order, similarly to Perl: + * http://blog.booking.com/hardening-perls-hash-function.html + */ + +/* INV_KEEP_FREE = 1 / (1 - max_load_factor) + * e.g. 1 / (1 - 0.8) = 5 ... keep one fifth of the buckets free. */ +#define INV_KEEP_FREE 5U + +/* Fields common to entries of all hashmap/set types */ +struct hashmap_base_entry { + const void *key; +}; + +/* Entry types for specific hashmap/set types + * hashmap_base_entry must be at the beginning of each entry struct. */ + +struct plain_hashmap_entry { + struct hashmap_base_entry b; + void *value; +}; + +struct ordered_hashmap_entry { + struct plain_hashmap_entry p; + unsigned iterate_next, iterate_previous; +}; + +struct set_entry { + struct hashmap_base_entry b; +}; + +/* In several functions it is advantageous to have the hash table extended + * virtually by a couple of additional buckets. We reserve special index values + * for these "swap" buckets. */ +#define _IDX_SWAP_BEGIN (UINT_MAX - 3) +#define IDX_PUT (_IDX_SWAP_BEGIN + 0) +#define IDX_TMP (_IDX_SWAP_BEGIN + 1) +#define _IDX_SWAP_END (_IDX_SWAP_BEGIN + 2) + +#define IDX_FIRST (UINT_MAX - 1) /* special index for freshly initialized iterators */ +#define IDX_NIL UINT_MAX /* special index value meaning "none" or "end" */ + +assert_cc(IDX_FIRST == _IDX_SWAP_END); +assert_cc(IDX_FIRST == _IDX_ITERATOR_FIRST); + +/* Storage space for the "swap" buckets. + * All entry types can fit into a ordered_hashmap_entry. */ +struct swap_entries { + struct ordered_hashmap_entry e[_IDX_SWAP_END - _IDX_SWAP_BEGIN]; +}; + +/* Distance from Initial Bucket */ +typedef uint8_t dib_raw_t; +#define DIB_RAW_OVERFLOW ((dib_raw_t)0xfdU) /* indicates DIB value is greater than representable */ +#define DIB_RAW_REHASH ((dib_raw_t)0xfeU) /* entry yet to be rehashed during in-place resize */ +#define DIB_RAW_FREE ((dib_raw_t)0xffU) /* a free bucket */ +#define DIB_RAW_INIT ((char)DIB_RAW_FREE) /* a byte to memset a DIB store with when initializing */ + +#define DIB_FREE UINT_MAX + +#ifdef ENABLE_DEBUG_HASHMAP +struct hashmap_debug_info { + LIST_FIELDS(struct hashmap_debug_info, debug_list); + unsigned max_entries; /* high watermark of n_entries */ + + /* who allocated this hashmap */ + int line; + const char *file; + const char *func; + + /* fields to detect modification while iterating */ + unsigned put_count; /* counts puts into the hashmap */ + unsigned rem_count; /* counts removals from hashmap */ + unsigned last_rem_idx; /* remembers last removal index */ +}; + +/* Tracks all existing hashmaps. Get at it from gdb. See sd_dump_hashmaps.py */ +static LIST_HEAD(struct hashmap_debug_info, hashmap_debug_list); + +#define HASHMAP_DEBUG_FIELDS struct hashmap_debug_info debug; + +#else /* !ENABLE_DEBUG_HASHMAP */ +#define HASHMAP_DEBUG_FIELDS +#endif /* ENABLE_DEBUG_HASHMAP */ + +enum HashmapType { + HASHMAP_TYPE_PLAIN, + HASHMAP_TYPE_ORDERED, + HASHMAP_TYPE_SET, + _HASHMAP_TYPE_MAX +}; + +struct _packed_ indirect_storage { + char *storage; /* where buckets and DIBs are stored */ + uint8_t hash_key[HASH_KEY_SIZE]; /* hash key; changes during resize */ + + unsigned n_entries; /* number of stored entries */ + unsigned n_buckets; /* number of buckets */ + + unsigned idx_lowest_entry; /* Index below which all buckets are free. + Makes "while(hashmap_steal_first())" loops + O(n) instead of O(n^2) for unordered hashmaps. */ + uint8_t _pad[3]; /* padding for the whole HashmapBase */ + /* The bitfields in HashmapBase complete the alignment of the whole thing. */ +}; + +struct direct_storage { + /* This gives us 39 bytes on 64bit, or 35 bytes on 32bit. + * That's room for 4 set_entries + 4 DIB bytes + 3 unused bytes on 64bit, + * or 7 set_entries + 7 DIB bytes + 0 unused bytes on 32bit. */ + char storage[sizeof(struct indirect_storage)]; +}; + +#define DIRECT_BUCKETS(entry_t) \ + (sizeof(struct direct_storage) / (sizeof(entry_t) + sizeof(dib_raw_t))) + +/* We should be able to store at least one entry directly. */ +assert_cc(DIRECT_BUCKETS(struct ordered_hashmap_entry) >= 1); + +/* We have 3 bits for n_direct_entries. */ +assert_cc(DIRECT_BUCKETS(struct set_entry) < (1 << 3)); + +/* Hashmaps with directly stored entries all use this shared hash key. + * It's no big deal if the key is guessed, because there can be only + * a handful of directly stored entries in a hashmap. When a hashmap + * outgrows direct storage, it gets its own key for indirect storage. */ +static uint8_t shared_hash_key[HASH_KEY_SIZE]; +static bool shared_hash_key_initialized; + +/* Fields that all hashmap/set types must have */ +struct HashmapBase { + const struct hash_ops *hash_ops; /* hash and compare ops to use */ + + union _packed_ { + struct indirect_storage indirect; /* if has_indirect */ + struct direct_storage direct; /* if !has_indirect */ + }; + + enum HashmapType type:2; /* HASHMAP_TYPE_* */ + bool has_indirect:1; /* whether indirect storage is used */ + unsigned n_direct_entries:3; /* Number of entries in direct storage. + * Only valid if !has_indirect. */ + bool from_pool:1; /* whether was allocated from mempool */ + HASHMAP_DEBUG_FIELDS /* optional hashmap_debug_info */ +}; + +/* Specific hash types + * HashmapBase must be at the beginning of each hashmap struct. */ + +struct Hashmap { + struct HashmapBase b; +}; + +struct OrderedHashmap { + struct HashmapBase b; + unsigned iterate_list_head, iterate_list_tail; +}; + +struct Set { + struct HashmapBase b; +}; + +DEFINE_MEMPOOL(hashmap_pool, Hashmap, 8); +DEFINE_MEMPOOL(ordered_hashmap_pool, OrderedHashmap, 8); +/* No need for a separate Set pool */ +assert_cc(sizeof(Hashmap) == sizeof(Set)); + +struct hashmap_type_info { + size_t head_size; + size_t entry_size; + struct mempool *mempool; + unsigned n_direct_buckets; +}; + +static const struct hashmap_type_info hashmap_type_info[_HASHMAP_TYPE_MAX] = { + [HASHMAP_TYPE_PLAIN] = { + .head_size = sizeof(Hashmap), + .entry_size = sizeof(struct plain_hashmap_entry), + .mempool = &hashmap_pool, + .n_direct_buckets = DIRECT_BUCKETS(struct plain_hashmap_entry), + }, + [HASHMAP_TYPE_ORDERED] = { + .head_size = sizeof(OrderedHashmap), + .entry_size = sizeof(struct ordered_hashmap_entry), + .mempool = &ordered_hashmap_pool, + .n_direct_buckets = DIRECT_BUCKETS(struct ordered_hashmap_entry), + }, + [HASHMAP_TYPE_SET] = { + .head_size = sizeof(Set), + .entry_size = sizeof(struct set_entry), + .mempool = &hashmap_pool, + .n_direct_buckets = DIRECT_BUCKETS(struct set_entry), + }, +}; + +unsigned long string_hash_func(const void *p, const uint8_t hash_key[HASH_KEY_SIZE]) { + uint64_t u; + siphash24((uint8_t*) &u, p, strlen(p), hash_key); + return (unsigned long) u; +} + +int string_compare_func(const void *a, const void *b) { + return strcmp(a, b); +} + +const struct hash_ops string_hash_ops = { + .hash = string_hash_func, + .compare = string_compare_func +}; + +unsigned long trivial_hash_func(const void *p, const uint8_t hash_key[HASH_KEY_SIZE]) { + uint64_t u; + siphash24((uint8_t*) &u, &p, sizeof(p), hash_key); + return (unsigned long) u; +} + +int trivial_compare_func(const void *a, const void *b) { + return a < b ? -1 : (a > b ? 1 : 0); +} + +const struct hash_ops trivial_hash_ops = { + .hash = trivial_hash_func, + .compare = trivial_compare_func +}; + +unsigned long uint64_hash_func(const void *p, const uint8_t hash_key[HASH_KEY_SIZE]) { + uint64_t u; + siphash24((uint8_t*) &u, p, sizeof(uint64_t), hash_key); + return (unsigned long) u; +} + +int uint64_compare_func(const void *_a, const void *_b) { + uint64_t a, b; + a = *(const uint64_t*) _a; + b = *(const uint64_t*) _b; + return a < b ? -1 : (a > b ? 1 : 0); +} + +const struct hash_ops uint64_hash_ops = { + .hash = uint64_hash_func, + .compare = uint64_compare_func +}; + +#if SIZEOF_DEV_T != 8 +unsigned long devt_hash_func(const void *p, const uint8_t hash_key[HASH_KEY_SIZE]) { + uint64_t u; + siphash24((uint8_t*) &u, p, sizeof(dev_t), hash_key); + return (unsigned long) u; +} + +int devt_compare_func(const void *_a, const void *_b) { + dev_t a, b; + a = *(const dev_t*) _a; + b = *(const dev_t*) _b; + return a < b ? -1 : (a > b ? 1 : 0); +} + +const struct hash_ops devt_hash_ops = { + .hash = devt_hash_func, + .compare = devt_compare_func +}; +#endif + +static unsigned n_buckets(HashmapBase *h) { + return h->has_indirect ? h->indirect.n_buckets + : hashmap_type_info[h->type].n_direct_buckets; +} + +static unsigned n_entries(HashmapBase *h) { + return h->has_indirect ? h->indirect.n_entries + : h->n_direct_entries; +} + +static void n_entries_inc(HashmapBase *h) { + if (h->has_indirect) + h->indirect.n_entries++; + else + h->n_direct_entries++; +} + +static void n_entries_dec(HashmapBase *h) { + if (h->has_indirect) + h->indirect.n_entries--; + else + h->n_direct_entries--; +} + +static char *storage_ptr(HashmapBase *h) { + return h->has_indirect ? h->indirect.storage + : h->direct.storage; +} + +static uint8_t *hash_key(HashmapBase *h) { + return h->has_indirect ? h->indirect.hash_key + : shared_hash_key; +} + +static unsigned base_bucket_hash(HashmapBase *h, const void *p) { + return (unsigned) (h->hash_ops->hash(p, hash_key(h)) % n_buckets(h)); +} +#define bucket_hash(h, p) base_bucket_hash(HASHMAP_BASE(h), p) + +static void get_hash_key(uint8_t hash_key[HASH_KEY_SIZE], bool reuse_is_ok) { + static uint8_t current[HASH_KEY_SIZE]; + static bool current_initialized = false; + + /* Returns a hash function key to use. In order to keep things + * fast we will not generate a new key each time we allocate a + * new hash table. Instead, we'll just reuse the most recently + * generated one, except if we never generated one or when we + * are rehashing an entire hash table because we reached a + * fill level */ + + if (!current_initialized || !reuse_is_ok) { + random_bytes(current, sizeof(current)); + current_initialized = true; + } + + memcpy(hash_key, current, sizeof(current)); +} + +static struct hashmap_base_entry *bucket_at(HashmapBase *h, unsigned idx) { + return (struct hashmap_base_entry*) + (storage_ptr(h) + idx * hashmap_type_info[h->type].entry_size); +} + +static struct plain_hashmap_entry *plain_bucket_at(Hashmap *h, unsigned idx) { + return (struct plain_hashmap_entry*) bucket_at(HASHMAP_BASE(h), idx); +} + +static struct ordered_hashmap_entry *ordered_bucket_at(OrderedHashmap *h, unsigned idx) { + return (struct ordered_hashmap_entry*) bucket_at(HASHMAP_BASE(h), idx); +} + +static struct set_entry *set_bucket_at(Set *h, unsigned idx) { + return (struct set_entry*) bucket_at(HASHMAP_BASE(h), idx); +} + +static struct ordered_hashmap_entry *bucket_at_swap(struct swap_entries *swap, unsigned idx) { + return &swap->e[idx - _IDX_SWAP_BEGIN]; +} + +/* Returns a pointer to the bucket at index idx. + * Understands real indexes and swap indexes, hence "_virtual". */ +static struct hashmap_base_entry *bucket_at_virtual(HashmapBase *h, struct swap_entries *swap, + unsigned idx) { + if (idx < _IDX_SWAP_BEGIN) + return bucket_at(h, idx); + + if (idx < _IDX_SWAP_END) + return &bucket_at_swap(swap, idx)->p.b; + + assert_not_reached("Invalid index"); +} + +static dib_raw_t *dib_raw_ptr(HashmapBase *h) { + return (dib_raw_t*) + (storage_ptr(h) + hashmap_type_info[h->type].entry_size * n_buckets(h)); +} + +static unsigned bucket_distance(HashmapBase *h, unsigned idx, unsigned from) { + return idx >= from ? idx - from + : n_buckets(h) + idx - from; +} + +static unsigned bucket_calculate_dib(HashmapBase *h, unsigned idx, dib_raw_t raw_dib) { + unsigned initial_bucket; + + if (raw_dib == DIB_RAW_FREE) + return DIB_FREE; + + if (_likely_(raw_dib < DIB_RAW_OVERFLOW)) + return raw_dib; + + /* + * Having an overflow DIB value is very unlikely. The hash function + * would have to be bad. For example, in a table of size 2^24 filled + * to load factor 0.9 the maximum observed DIB is only about 60. + * In theory (assuming I used Maxima correctly), for an infinite size + * hash table with load factor 0.8 the probability of a given entry + * having DIB > 40 is 1.9e-8. + * This returns the correct DIB value by recomputing the hash value in + * the unlikely case. XXX Hitting this case could be a hint to rehash. + */ + initial_bucket = bucket_hash(h, bucket_at(h, idx)->key); + return bucket_distance(h, idx, initial_bucket); +} + +static void bucket_set_dib(HashmapBase *h, unsigned idx, unsigned dib) { + dib_raw_ptr(h)[idx] = dib != DIB_FREE ? MIN(dib, DIB_RAW_OVERFLOW) : DIB_RAW_FREE; +} + +static unsigned skip_free_buckets(HashmapBase *h, unsigned idx) { + dib_raw_t *dibs; + + dibs = dib_raw_ptr(h); + + for ( ; idx < n_buckets(h); idx++) + if (dibs[idx] != DIB_RAW_FREE) + return idx; + + return IDX_NIL; +} + +static void bucket_mark_free(HashmapBase *h, unsigned idx) { + memzero(bucket_at(h, idx), hashmap_type_info[h->type].entry_size); + bucket_set_dib(h, idx, DIB_FREE); +} + +static void bucket_move_entry(HashmapBase *h, struct swap_entries *swap, + unsigned from, unsigned to) { + struct hashmap_base_entry *e_from, *e_to; + + assert(from != to); + + e_from = bucket_at_virtual(h, swap, from); + e_to = bucket_at_virtual(h, swap, to); + + memcpy(e_to, e_from, hashmap_type_info[h->type].entry_size); + + if (h->type == HASHMAP_TYPE_ORDERED) { + OrderedHashmap *lh = (OrderedHashmap*) h; + struct ordered_hashmap_entry *le, *le_to; + + le_to = (struct ordered_hashmap_entry*) e_to; + + if (le_to->iterate_next != IDX_NIL) { + le = (struct ordered_hashmap_entry*) + bucket_at_virtual(h, swap, le_to->iterate_next); + le->iterate_previous = to; + } + + if (le_to->iterate_previous != IDX_NIL) { + le = (struct ordered_hashmap_entry*) + bucket_at_virtual(h, swap, le_to->iterate_previous); + le->iterate_next = to; + } + + if (lh->iterate_list_head == from) + lh->iterate_list_head = to; + if (lh->iterate_list_tail == from) + lh->iterate_list_tail = to; + } +} + +static unsigned next_idx(HashmapBase *h, unsigned idx) { + return (idx + 1U) % n_buckets(h); +} + +static unsigned prev_idx(HashmapBase *h, unsigned idx) { + return (n_buckets(h) + idx - 1U) % n_buckets(h); +} + +static void *entry_value(HashmapBase *h, struct hashmap_base_entry *e) { + switch (h->type) { + + case HASHMAP_TYPE_PLAIN: + case HASHMAP_TYPE_ORDERED: + return ((struct plain_hashmap_entry*)e)->value; + + case HASHMAP_TYPE_SET: + return (void*) e->key; + + default: + assert_not_reached("Unknown hashmap type"); + } +} + +static void base_remove_entry(HashmapBase *h, unsigned idx) { + unsigned left, right, prev, dib; + dib_raw_t raw_dib, *dibs; + + dibs = dib_raw_ptr(h); + assert(dibs[idx] != DIB_RAW_FREE); + +#ifdef ENABLE_DEBUG_HASHMAP + h->debug.rem_count++; + h->debug.last_rem_idx = idx; +#endif + + left = idx; + /* Find the stop bucket ("right"). It is either free or has DIB == 0. */ + for (right = next_idx(h, left); ; right = next_idx(h, right)) { + raw_dib = dibs[right]; + if (raw_dib == 0 || raw_dib == DIB_RAW_FREE) + break; + + /* The buckets are not supposed to be all occupied and with DIB > 0. + * That would mean we could make everyone better off by shifting them + * backward. This scenario is impossible. */ + assert(left != right); + } + + if (h->type == HASHMAP_TYPE_ORDERED) { + OrderedHashmap *lh = (OrderedHashmap*) h; + struct ordered_hashmap_entry *le = ordered_bucket_at(lh, idx); + + if (le->iterate_next != IDX_NIL) + ordered_bucket_at(lh, le->iterate_next)->iterate_previous = le->iterate_previous; + else + lh->iterate_list_tail = le->iterate_previous; + + if (le->iterate_previous != IDX_NIL) + ordered_bucket_at(lh, le->iterate_previous)->iterate_next = le->iterate_next; + else + lh->iterate_list_head = le->iterate_next; + } + + /* Now shift all buckets in the interval (left, right) one step backwards */ + for (prev = left, left = next_idx(h, left); left != right; + prev = left, left = next_idx(h, left)) { + dib = bucket_calculate_dib(h, left, dibs[left]); + assert(dib != 0); + bucket_move_entry(h, NULL, left, prev); + bucket_set_dib(h, prev, dib - 1); + } + + bucket_mark_free(h, prev); + n_entries_dec(h); +} +#define remove_entry(h, idx) base_remove_entry(HASHMAP_BASE(h), idx) + +static unsigned hashmap_iterate_in_insertion_order(OrderedHashmap *h, Iterator *i) { + struct ordered_hashmap_entry *e; + unsigned idx; + + assert(h); + assert(i); + + if (i->idx == IDX_NIL) + goto at_end; + + if (i->idx == IDX_FIRST && h->iterate_list_head == IDX_NIL) + goto at_end; + + if (i->idx == IDX_FIRST) { + idx = h->iterate_list_head; + e = ordered_bucket_at(h, idx); + } else { + idx = i->idx; + e = ordered_bucket_at(h, idx); + /* + * We allow removing the current entry while iterating, but removal may cause + * a backward shift. The next entry may thus move one bucket to the left. + * To detect when it happens, we remember the key pointer of the entry we were + * going to iterate next. If it does not match, there was a backward shift. + */ + if (e->p.b.key != i->next_key) { + idx = prev_idx(HASHMAP_BASE(h), idx); + e = ordered_bucket_at(h, idx); + } + assert(e->p.b.key == i->next_key); + } + +#ifdef ENABLE_DEBUG_HASHMAP + i->prev_idx = idx; +#endif + + if (e->iterate_next != IDX_NIL) { + struct ordered_hashmap_entry *n; + i->idx = e->iterate_next; + n = ordered_bucket_at(h, i->idx); + i->next_key = n->p.b.key; + } else + i->idx = IDX_NIL; + + return idx; + +at_end: + i->idx = IDX_NIL; + return IDX_NIL; +} + +static unsigned hashmap_iterate_in_internal_order(HashmapBase *h, Iterator *i) { + unsigned idx; + + assert(h); + assert(i); + + if (i->idx == IDX_NIL) + goto at_end; + + if (i->idx == IDX_FIRST) { + /* fast forward to the first occupied bucket */ + if (h->has_indirect) { + i->idx = skip_free_buckets(h, h->indirect.idx_lowest_entry); + h->indirect.idx_lowest_entry = i->idx; + } else + i->idx = skip_free_buckets(h, 0); + + if (i->idx == IDX_NIL) + goto at_end; + } else { + struct hashmap_base_entry *e; + + assert(i->idx > 0); + + e = bucket_at(h, i->idx); + /* + * We allow removing the current entry while iterating, but removal may cause + * a backward shift. The next entry may thus move one bucket to the left. + * To detect when it happens, we remember the key pointer of the entry we were + * going to iterate next. If it does not match, there was a backward shift. + */ + if (e->key != i->next_key) + e = bucket_at(h, --i->idx); + + assert(e->key == i->next_key); + } + + idx = i->idx; +#ifdef ENABLE_DEBUG_HASHMAP + i->prev_idx = idx; +#endif + + i->idx = skip_free_buckets(h, i->idx + 1); + if (i->idx != IDX_NIL) + i->next_key = bucket_at(h, i->idx)->key; + else + i->idx = IDX_NIL; + + return idx; + +at_end: + i->idx = IDX_NIL; + return IDX_NIL; +} + +static unsigned hashmap_iterate_entry(HashmapBase *h, Iterator *i) { + if (!h) { + i->idx = IDX_NIL; + return IDX_NIL; + } + +#ifdef ENABLE_DEBUG_HASHMAP + if (i->idx == IDX_FIRST) { + i->put_count = h->debug.put_count; + i->rem_count = h->debug.rem_count; + } else { + /* While iterating, must not add any new entries */ + assert(i->put_count == h->debug.put_count); + /* ... or remove entries other than the current one */ + assert(i->rem_count == h->debug.rem_count || + (i->rem_count == h->debug.rem_count - 1 && + i->prev_idx == h->debug.last_rem_idx)); + /* Reset our removals counter */ + i->rem_count = h->debug.rem_count; + } +#endif + + return h->type == HASHMAP_TYPE_ORDERED ? hashmap_iterate_in_insertion_order((OrderedHashmap*) h, i) + : hashmap_iterate_in_internal_order(h, i); +} + +void *internal_hashmap_iterate(HashmapBase *h, Iterator *i, const void **key) { + struct hashmap_base_entry *e; + void *data; + unsigned idx; + + idx = hashmap_iterate_entry(h, i); + if (idx == IDX_NIL) { + if (key) + *key = NULL; + + return NULL; + } + + e = bucket_at(h, idx); + data = entry_value(h, e); + if (key) + *key = e->key; + + return data; +} + +void *set_iterate(Set *s, Iterator *i) { + return internal_hashmap_iterate(HASHMAP_BASE(s), i, NULL); +} + +#define HASHMAP_FOREACH_IDX(idx, h, i) \ + for ((i) = ITERATOR_FIRST, (idx) = hashmap_iterate_entry((h), &(i)); \ + (idx != IDX_NIL); \ + (idx) = hashmap_iterate_entry((h), &(i))) + +static void reset_direct_storage(HashmapBase *h) { + const struct hashmap_type_info *hi = &hashmap_type_info[h->type]; + void *p; + + assert(!h->has_indirect); + + p = mempset(h->direct.storage, 0, hi->entry_size * hi->n_direct_buckets); + memset(p, DIB_RAW_INIT, sizeof(dib_raw_t) * hi->n_direct_buckets); +} + +static struct HashmapBase *hashmap_base_new(const struct hash_ops *hash_ops, enum HashmapType type HASHMAP_DEBUG_PARAMS) { + HashmapBase *h; + const struct hashmap_type_info *hi = &hashmap_type_info[type]; + bool use_pool; + + use_pool = is_main_thread(); + + h = use_pool ? mempool_alloc0_tile(hi->mempool) : malloc0(hi->head_size); + + if (!h) + return NULL; + + h->type = type; + h->from_pool = use_pool; + h->hash_ops = hash_ops ? hash_ops : &trivial_hash_ops; + + if (type == HASHMAP_TYPE_ORDERED) { + OrderedHashmap *lh = (OrderedHashmap*)h; + lh->iterate_list_head = lh->iterate_list_tail = IDX_NIL; + } + + reset_direct_storage(h); + + if (!shared_hash_key_initialized) { + random_bytes(shared_hash_key, sizeof(shared_hash_key)); + shared_hash_key_initialized= true; + } + +#ifdef ENABLE_DEBUG_HASHMAP + LIST_PREPEND(debug_list, hashmap_debug_list, &h->debug); + h->debug.func = func; + h->debug.file = file; + h->debug.line = line; +#endif + + return h; +} + +Hashmap *internal_hashmap_new(const struct hash_ops *hash_ops HASHMAP_DEBUG_PARAMS) { + return (Hashmap*) hashmap_base_new(hash_ops, HASHMAP_TYPE_PLAIN HASHMAP_DEBUG_PASS_ARGS); +} + +OrderedHashmap *internal_ordered_hashmap_new(const struct hash_ops *hash_ops HASHMAP_DEBUG_PARAMS) { + return (OrderedHashmap*) hashmap_base_new(hash_ops, HASHMAP_TYPE_ORDERED HASHMAP_DEBUG_PASS_ARGS); +} + +Set *internal_set_new(const struct hash_ops *hash_ops HASHMAP_DEBUG_PARAMS) { + return (Set*) hashmap_base_new(hash_ops, HASHMAP_TYPE_SET HASHMAP_DEBUG_PASS_ARGS); +} + +static int hashmap_base_ensure_allocated(HashmapBase **h, const struct hash_ops *hash_ops, + enum HashmapType type HASHMAP_DEBUG_PARAMS) { + HashmapBase *q; + + assert(h); + + if (*h) + return 0; + + q = hashmap_base_new(hash_ops, type HASHMAP_DEBUG_PASS_ARGS); + if (!q) + return -ENOMEM; + + *h = q; + return 0; +} + +int internal_hashmap_ensure_allocated(Hashmap **h, const struct hash_ops *hash_ops HASHMAP_DEBUG_PARAMS) { + return hashmap_base_ensure_allocated((HashmapBase**)h, hash_ops, HASHMAP_TYPE_PLAIN HASHMAP_DEBUG_PASS_ARGS); +} + +int internal_ordered_hashmap_ensure_allocated(OrderedHashmap **h, const struct hash_ops *hash_ops HASHMAP_DEBUG_PARAMS) { + return hashmap_base_ensure_allocated((HashmapBase**)h, hash_ops, HASHMAP_TYPE_ORDERED HASHMAP_DEBUG_PASS_ARGS); +} + +int internal_set_ensure_allocated(Set **s, const struct hash_ops *hash_ops HASHMAP_DEBUG_PARAMS) { + return hashmap_base_ensure_allocated((HashmapBase**)s, hash_ops, HASHMAP_TYPE_SET HASHMAP_DEBUG_PASS_ARGS); +} + +static void hashmap_free_no_clear(HashmapBase *h) { + assert(!h->has_indirect); + assert(!h->n_direct_entries); + +#ifdef ENABLE_DEBUG_HASHMAP + LIST_REMOVE(debug_list, hashmap_debug_list, &h->debug); +#endif + + if (h->from_pool) + mempool_free_tile(hashmap_type_info[h->type].mempool, h); + else + free(h); +} + +HashmapBase *internal_hashmap_free(HashmapBase *h) { + + /* Free the hashmap, but nothing in it */ + + if (h) { + internal_hashmap_clear(h); + hashmap_free_no_clear(h); + } + + return NULL; +} + +HashmapBase *internal_hashmap_free_free(HashmapBase *h) { + + /* Free the hashmap and all data objects in it, but not the + * keys */ + + if (h) { + internal_hashmap_clear_free(h); + hashmap_free_no_clear(h); + } + + return NULL; +} + +Hashmap *hashmap_free_free_free(Hashmap *h) { + + /* Free the hashmap and all data and key objects in it */ + + if (h) { + hashmap_clear_free_free(h); + hashmap_free_no_clear(HASHMAP_BASE(h)); + } + + return NULL; +} + +void internal_hashmap_clear(HashmapBase *h) { + if (!h) + return; + + if (h->has_indirect) { + free(h->indirect.storage); + h->has_indirect = false; + } + + h->n_direct_entries = 0; + reset_direct_storage(h); + + if (h->type == HASHMAP_TYPE_ORDERED) { + OrderedHashmap *lh = (OrderedHashmap*) h; + lh->iterate_list_head = lh->iterate_list_tail = IDX_NIL; + } +} + +void internal_hashmap_clear_free(HashmapBase *h) { + unsigned idx; + + if (!h) + return; + + for (idx = skip_free_buckets(h, 0); idx != IDX_NIL; + idx = skip_free_buckets(h, idx + 1)) + free(entry_value(h, bucket_at(h, idx))); + + internal_hashmap_clear(h); +} + +void hashmap_clear_free_free(Hashmap *h) { + unsigned idx; + + if (!h) + return; + + for (idx = skip_free_buckets(HASHMAP_BASE(h), 0); idx != IDX_NIL; + idx = skip_free_buckets(HASHMAP_BASE(h), idx + 1)) { + struct plain_hashmap_entry *e = plain_bucket_at(h, idx); + free((void*)e->b.key); + free(e->value); + } + + internal_hashmap_clear(HASHMAP_BASE(h)); +} + +static int resize_buckets(HashmapBase *h, unsigned entries_add); + +/* + * Finds an empty bucket to put an entry into, starting the scan at 'idx'. + * Performs Robin Hood swaps as it goes. The entry to put must be placed + * by the caller into swap slot IDX_PUT. + * If used for in-place resizing, may leave a displaced entry in swap slot + * IDX_PUT. Caller must rehash it next. + * Returns: true if it left a displaced entry to rehash next in IDX_PUT, + * false otherwise. + */ +static bool hashmap_put_robin_hood(HashmapBase *h, unsigned idx, + struct swap_entries *swap) { + dib_raw_t raw_dib, *dibs; + unsigned dib, distance; + +#ifdef ENABLE_DEBUG_HASHMAP + h->debug.put_count++; +#endif + + dibs = dib_raw_ptr(h); + + for (distance = 0; ; distance++) { + raw_dib = dibs[idx]; + if (raw_dib == DIB_RAW_FREE || raw_dib == DIB_RAW_REHASH) { + if (raw_dib == DIB_RAW_REHASH) + bucket_move_entry(h, swap, idx, IDX_TMP); + + if (h->has_indirect && h->indirect.idx_lowest_entry > idx) + h->indirect.idx_lowest_entry = idx; + + bucket_set_dib(h, idx, distance); + bucket_move_entry(h, swap, IDX_PUT, idx); + if (raw_dib == DIB_RAW_REHASH) { + bucket_move_entry(h, swap, IDX_TMP, IDX_PUT); + return true; + } + + return false; + } + + dib = bucket_calculate_dib(h, idx, raw_dib); + + if (dib < distance) { + /* Found a wealthier entry. Go Robin Hood! */ + bucket_set_dib(h, idx, distance); + + /* swap the entries */ + bucket_move_entry(h, swap, idx, IDX_TMP); + bucket_move_entry(h, swap, IDX_PUT, idx); + bucket_move_entry(h, swap, IDX_TMP, IDX_PUT); + + distance = dib; + } + + idx = next_idx(h, idx); + } +} + +/* + * Puts an entry into a hashmap, boldly - no check whether key already exists. + * The caller must place the entry (only its key and value, not link indexes) + * in swap slot IDX_PUT. + * Caller must ensure: the key does not exist yet in the hashmap. + * that resize is not needed if !may_resize. + * Returns: 1 if entry was put successfully. + * -ENOMEM if may_resize==true and resize failed with -ENOMEM. + * Cannot return -ENOMEM if !may_resize. + */ +static int hashmap_base_put_boldly(HashmapBase *h, unsigned idx, + struct swap_entries *swap, bool may_resize) { + struct ordered_hashmap_entry *new_entry; + int r; + + assert(idx < n_buckets(h)); + + new_entry = bucket_at_swap(swap, IDX_PUT); + + if (may_resize) { + r = resize_buckets(h, 1); + if (r < 0) + return r; + if (r > 0) + idx = bucket_hash(h, new_entry->p.b.key); + } + assert(n_entries(h) < n_buckets(h)); + + if (h->type == HASHMAP_TYPE_ORDERED) { + OrderedHashmap *lh = (OrderedHashmap*) h; + + new_entry->iterate_next = IDX_NIL; + new_entry->iterate_previous = lh->iterate_list_tail; + + if (lh->iterate_list_tail != IDX_NIL) { + struct ordered_hashmap_entry *old_tail; + + old_tail = ordered_bucket_at(lh, lh->iterate_list_tail); + assert(old_tail->iterate_next == IDX_NIL); + old_tail->iterate_next = IDX_PUT; + } + + lh->iterate_list_tail = IDX_PUT; + if (lh->iterate_list_head == IDX_NIL) + lh->iterate_list_head = IDX_PUT; + } + + assert_se(hashmap_put_robin_hood(h, idx, swap) == false); + + n_entries_inc(h); +#ifdef ENABLE_DEBUG_HASHMAP + h->debug.max_entries = MAX(h->debug.max_entries, n_entries(h)); +#endif + + return 1; +} +#define hashmap_put_boldly(h, idx, swap, may_resize) \ + hashmap_base_put_boldly(HASHMAP_BASE(h), idx, swap, may_resize) + +/* + * Returns 0 if resize is not needed. + * 1 if successfully resized. + * -ENOMEM on allocation failure. + */ +static int resize_buckets(HashmapBase *h, unsigned entries_add) { + struct swap_entries swap; + char *new_storage; + dib_raw_t *old_dibs, *new_dibs; + const struct hashmap_type_info *hi; + unsigned idx, optimal_idx; + unsigned old_n_buckets, new_n_buckets, n_rehashed, new_n_entries; + uint8_t new_shift; + bool rehash_next; + + assert(h); + + hi = &hashmap_type_info[h->type]; + new_n_entries = n_entries(h) + entries_add; + + /* overflow? */ + if (_unlikely_(new_n_entries < entries_add)) + return -ENOMEM; + + /* For direct storage we allow 100% load, because it's tiny. */ + if (!h->has_indirect && new_n_entries <= hi->n_direct_buckets) + return 0; + + /* + * Load factor = n/m = 1 - (1/INV_KEEP_FREE). + * From it follows: m = n + n/(INV_KEEP_FREE - 1) + */ + new_n_buckets = new_n_entries + new_n_entries / (INV_KEEP_FREE - 1); + /* overflow? */ + if (_unlikely_(new_n_buckets < new_n_entries)) + return -ENOMEM; + + if (_unlikely_(new_n_buckets > UINT_MAX / (hi->entry_size + sizeof(dib_raw_t)))) + return -ENOMEM; + + old_n_buckets = n_buckets(h); + + if (_likely_(new_n_buckets <= old_n_buckets)) + return 0; + + new_shift = log2u_round_up(MAX( + new_n_buckets * (hi->entry_size + sizeof(dib_raw_t)), + 2 * sizeof(struct direct_storage))); + + /* Realloc storage (buckets and DIB array). */ + new_storage = realloc(h->has_indirect ? h->indirect.storage : NULL, + 1U << new_shift); + if (!new_storage) + return -ENOMEM; + + /* Must upgrade direct to indirect storage. */ + if (!h->has_indirect) { + memcpy(new_storage, h->direct.storage, + old_n_buckets * (hi->entry_size + sizeof(dib_raw_t))); + h->indirect.n_entries = h->n_direct_entries; + h->indirect.idx_lowest_entry = 0; + h->n_direct_entries = 0; + } + + /* Get a new hash key. If we've just upgraded to indirect storage, + * allow reusing a previously generated key. It's still a different key + * from the shared one that we used for direct storage. */ + get_hash_key(h->indirect.hash_key, !h->has_indirect); + + h->has_indirect = true; + h->indirect.storage = new_storage; + h->indirect.n_buckets = (1U << new_shift) / + (hi->entry_size + sizeof(dib_raw_t)); + + old_dibs = (dib_raw_t*)(new_storage + hi->entry_size * old_n_buckets); + new_dibs = dib_raw_ptr(h); + + /* + * Move the DIB array to the new place, replacing valid DIB values with + * DIB_RAW_REHASH to indicate all of the used buckets need rehashing. + * Note: Overlap is not possible, because we have at least doubled the + * number of buckets and dib_raw_t is smaller than any entry type. + */ + for (idx = 0; idx < old_n_buckets; idx++) { + assert(old_dibs[idx] != DIB_RAW_REHASH); + new_dibs[idx] = old_dibs[idx] == DIB_RAW_FREE ? DIB_RAW_FREE + : DIB_RAW_REHASH; + } + + /* Zero the area of newly added entries (including the old DIB area) */ + memzero(bucket_at(h, old_n_buckets), + (n_buckets(h) - old_n_buckets) * hi->entry_size); + + /* The upper half of the new DIB array needs initialization */ + memset(&new_dibs[old_n_buckets], DIB_RAW_INIT, + (n_buckets(h) - old_n_buckets) * sizeof(dib_raw_t)); + + /* Rehash entries that need it */ + n_rehashed = 0; + for (idx = 0; idx < old_n_buckets; idx++) { + if (new_dibs[idx] != DIB_RAW_REHASH) + continue; + + optimal_idx = bucket_hash(h, bucket_at(h, idx)->key); + + /* + * Not much to do if by luck the entry hashes to its current + * location. Just set its DIB. + */ + if (optimal_idx == idx) { + new_dibs[idx] = 0; + n_rehashed++; + continue; + } + + new_dibs[idx] = DIB_RAW_FREE; + bucket_move_entry(h, &swap, idx, IDX_PUT); + /* bucket_move_entry does not clear the source */ + memzero(bucket_at(h, idx), hi->entry_size); + + do { + /* + * Find the new bucket for the current entry. This may make + * another entry homeless and load it into IDX_PUT. + */ + rehash_next = hashmap_put_robin_hood(h, optimal_idx, &swap); + n_rehashed++; + + /* Did the current entry displace another one? */ + if (rehash_next) + optimal_idx = bucket_hash(h, bucket_at_swap(&swap, IDX_PUT)->p.b.key); + } while (rehash_next); + } + + assert(n_rehashed == n_entries(h)); + + return 1; +} + +/* + * Finds an entry with a matching key + * Returns: index of the found entry, or IDX_NIL if not found. + */ +static unsigned base_bucket_scan(HashmapBase *h, unsigned idx, const void *key) { + struct hashmap_base_entry *e; + unsigned dib, distance; + dib_raw_t *dibs = dib_raw_ptr(h); + + assert(idx < n_buckets(h)); + + for (distance = 0; ; distance++) { + if (dibs[idx] == DIB_RAW_FREE) + return IDX_NIL; + + dib = bucket_calculate_dib(h, idx, dibs[idx]); + + if (dib < distance) + return IDX_NIL; + if (dib == distance) { + e = bucket_at(h, idx); + if (h->hash_ops->compare(e->key, key) == 0) + return idx; + } + + idx = next_idx(h, idx); + } +} +#define bucket_scan(h, idx, key) base_bucket_scan(HASHMAP_BASE(h), idx, key) + +int hashmap_put(Hashmap *h, const void *key, void *value) { + struct swap_entries swap; + struct plain_hashmap_entry *e; + unsigned hash, idx; + + assert(h); + + hash = bucket_hash(h, key); + idx = bucket_scan(h, hash, key); + if (idx != IDX_NIL) { + e = plain_bucket_at(h, idx); + if (e->value == value) + return 0; + return -EEXIST; + } + + e = &bucket_at_swap(&swap, IDX_PUT)->p; + e->b.key = key; + e->value = value; + return hashmap_put_boldly(h, hash, &swap, true); +} + +int set_put(Set *s, const void *key) { + struct swap_entries swap; + struct hashmap_base_entry *e; + unsigned hash, idx; + + assert(s); + + hash = bucket_hash(s, key); + idx = bucket_scan(s, hash, key); + if (idx != IDX_NIL) + return 0; + + e = &bucket_at_swap(&swap, IDX_PUT)->p.b; + e->key = key; + return hashmap_put_boldly(s, hash, &swap, true); +} + +int hashmap_replace(Hashmap *h, const void *key, void *value) { + struct swap_entries swap; + struct plain_hashmap_entry *e; + unsigned hash, idx; + + assert(h); + + hash = bucket_hash(h, key); + idx = bucket_scan(h, hash, key); + if (idx != IDX_NIL) { + e = plain_bucket_at(h, idx); +#ifdef ENABLE_DEBUG_HASHMAP + /* Although the key is equal, the key pointer may have changed, + * and this would break our assumption for iterating. So count + * this operation as incompatible with iteration. */ + if (e->b.key != key) { + h->b.debug.put_count++; + h->b.debug.rem_count++; + h->b.debug.last_rem_idx = idx; + } +#endif + e->b.key = key; + e->value = value; + return 0; + } + + e = &bucket_at_swap(&swap, IDX_PUT)->p; + e->b.key = key; + e->value = value; + return hashmap_put_boldly(h, hash, &swap, true); +} + +int hashmap_update(Hashmap *h, const void *key, void *value) { + struct plain_hashmap_entry *e; + unsigned hash, idx; + + assert(h); + + hash = bucket_hash(h, key); + idx = bucket_scan(h, hash, key); + if (idx == IDX_NIL) + return -ENOENT; + + e = plain_bucket_at(h, idx); + e->value = value; + return 0; +} + +void *internal_hashmap_get(HashmapBase *h, const void *key) { + struct hashmap_base_entry *e; + unsigned hash, idx; + + if (!h) + return NULL; + + hash = bucket_hash(h, key); + idx = bucket_scan(h, hash, key); + if (idx == IDX_NIL) + return NULL; + + e = bucket_at(h, idx); + return entry_value(h, e); +} + +void *hashmap_get2(Hashmap *h, const void *key, void **key2) { + struct plain_hashmap_entry *e; + unsigned hash, idx; + + if (!h) + return NULL; + + hash = bucket_hash(h, key); + idx = bucket_scan(h, hash, key); + if (idx == IDX_NIL) + return NULL; + + e = plain_bucket_at(h, idx); + if (key2) + *key2 = (void*) e->b.key; + + return e->value; +} + +bool internal_hashmap_contains(HashmapBase *h, const void *key) { + unsigned hash; + + if (!h) + return false; + + hash = bucket_hash(h, key); + return bucket_scan(h, hash, key) != IDX_NIL; +} + +void *internal_hashmap_remove(HashmapBase *h, const void *key) { + struct hashmap_base_entry *e; + unsigned hash, idx; + void *data; + + if (!h) + return NULL; + + hash = bucket_hash(h, key); + idx = bucket_scan(h, hash, key); + if (idx == IDX_NIL) + return NULL; + + e = bucket_at(h, idx); + data = entry_value(h, e); + remove_entry(h, idx); + + return data; +} + +void *hashmap_remove2(Hashmap *h, const void *key, void **rkey) { + struct plain_hashmap_entry *e; + unsigned hash, idx; + void *data; + + if (!h) { + if (rkey) + *rkey = NULL; + return NULL; + } + + hash = bucket_hash(h, key); + idx = bucket_scan(h, hash, key); + if (idx == IDX_NIL) { + if (rkey) + *rkey = NULL; + return NULL; + } + + e = plain_bucket_at(h, idx); + data = e->value; + if (rkey) + *rkey = (void*) e->b.key; + + remove_entry(h, idx); + + return data; +} + +int hashmap_remove_and_put(Hashmap *h, const void *old_key, const void *new_key, void *value) { + struct swap_entries swap; + struct plain_hashmap_entry *e; + unsigned old_hash, new_hash, idx; + + if (!h) + return -ENOENT; + + old_hash = bucket_hash(h, old_key); + idx = bucket_scan(h, old_hash, old_key); + if (idx == IDX_NIL) + return -ENOENT; + + new_hash = bucket_hash(h, new_key); + if (bucket_scan(h, new_hash, new_key) != IDX_NIL) + return -EEXIST; + + remove_entry(h, idx); + + e = &bucket_at_swap(&swap, IDX_PUT)->p; + e->b.key = new_key; + e->value = value; + assert_se(hashmap_put_boldly(h, new_hash, &swap, false) == 1); + + return 0; +} + +int set_remove_and_put(Set *s, const void *old_key, const void *new_key) { + struct swap_entries swap; + struct hashmap_base_entry *e; + unsigned old_hash, new_hash, idx; + + if (!s) + return -ENOENT; + + old_hash = bucket_hash(s, old_key); + idx = bucket_scan(s, old_hash, old_key); + if (idx == IDX_NIL) + return -ENOENT; + + new_hash = bucket_hash(s, new_key); + if (bucket_scan(s, new_hash, new_key) != IDX_NIL) + return -EEXIST; + + remove_entry(s, idx); + + e = &bucket_at_swap(&swap, IDX_PUT)->p.b; + e->key = new_key; + assert_se(hashmap_put_boldly(s, new_hash, &swap, false) == 1); + + return 0; +} + +int hashmap_remove_and_replace(Hashmap *h, const void *old_key, const void *new_key, void *value) { + struct swap_entries swap; + struct plain_hashmap_entry *e; + unsigned old_hash, new_hash, idx_old, idx_new; + + if (!h) + return -ENOENT; + + old_hash = bucket_hash(h, old_key); + idx_old = bucket_scan(h, old_hash, old_key); + if (idx_old == IDX_NIL) + return -ENOENT; + + old_key = bucket_at(HASHMAP_BASE(h), idx_old)->key; + + new_hash = bucket_hash(h, new_key); + idx_new = bucket_scan(h, new_hash, new_key); + if (idx_new != IDX_NIL) + if (idx_old != idx_new) { + remove_entry(h, idx_new); + /* Compensate for a possible backward shift. */ + if (old_key != bucket_at(HASHMAP_BASE(h), idx_old)->key) + idx_old = prev_idx(HASHMAP_BASE(h), idx_old); + assert(old_key == bucket_at(HASHMAP_BASE(h), idx_old)->key); + } + + remove_entry(h, idx_old); + + e = &bucket_at_swap(&swap, IDX_PUT)->p; + e->b.key = new_key; + e->value = value; + assert_se(hashmap_put_boldly(h, new_hash, &swap, false) == 1); + + return 0; +} + +void *hashmap_remove_value(Hashmap *h, const void *key, void *value) { + struct plain_hashmap_entry *e; + unsigned hash, idx; + + if (!h) + return NULL; + + hash = bucket_hash(h, key); + idx = bucket_scan(h, hash, key); + if (idx == IDX_NIL) + return NULL; + + e = plain_bucket_at(h, idx); + if (e->value != value) + return NULL; + + remove_entry(h, idx); + + return value; +} + +static unsigned find_first_entry(HashmapBase *h) { + Iterator i = ITERATOR_FIRST; + + if (!h || !n_entries(h)) + return IDX_NIL; + + return hashmap_iterate_entry(h, &i); +} + +void *internal_hashmap_first(HashmapBase *h) { + unsigned idx; + + idx = find_first_entry(h); + if (idx == IDX_NIL) + return NULL; + + return entry_value(h, bucket_at(h, idx)); +} + +void *internal_hashmap_first_key(HashmapBase *h) { + struct hashmap_base_entry *e; + unsigned idx; + + idx = find_first_entry(h); + if (idx == IDX_NIL) + return NULL; + + e = bucket_at(h, idx); + return (void*) e->key; +} + +void *internal_hashmap_steal_first(HashmapBase *h) { + struct hashmap_base_entry *e; + void *data; + unsigned idx; + + idx = find_first_entry(h); + if (idx == IDX_NIL) + return NULL; + + e = bucket_at(h, idx); + data = entry_value(h, e); + remove_entry(h, idx); + + return data; +} + +void *internal_hashmap_steal_first_key(HashmapBase *h) { + struct hashmap_base_entry *e; + void *key; + unsigned idx; + + idx = find_first_entry(h); + if (idx == IDX_NIL) + return NULL; + + e = bucket_at(h, idx); + key = (void*) e->key; + remove_entry(h, idx); + + return key; +} + +unsigned internal_hashmap_size(HashmapBase *h) { + + if (!h) + return 0; + + return n_entries(h); +} + +unsigned internal_hashmap_buckets(HashmapBase *h) { + + if (!h) + return 0; + + return n_buckets(h); +} + +int internal_hashmap_merge(Hashmap *h, Hashmap *other) { + Iterator i; + unsigned idx; + + assert(h); + + HASHMAP_FOREACH_IDX(idx, HASHMAP_BASE(other), i) { + struct plain_hashmap_entry *pe = plain_bucket_at(other, idx); + int r; + + r = hashmap_put(h, pe->b.key, pe->value); + if (r < 0 && r != -EEXIST) + return r; + } + + return 0; +} + +int set_merge(Set *s, Set *other) { + Iterator i; + unsigned idx; + + assert(s); + + HASHMAP_FOREACH_IDX(idx, HASHMAP_BASE(other), i) { + struct set_entry *se = set_bucket_at(other, idx); + int r; + + r = set_put(s, se->b.key); + if (r < 0) + return r; + } + + return 0; +} + +int internal_hashmap_reserve(HashmapBase *h, unsigned entries_add) { + int r; + + assert(h); + + r = resize_buckets(h, entries_add); + if (r < 0) + return r; + + return 0; +} + +/* + * The same as hashmap_merge(), but every new item from other is moved to h. + * Keys already in h are skipped and stay in other. + * Returns: 0 on success. + * -ENOMEM on alloc failure, in which case no move has been done. + */ +int internal_hashmap_move(HashmapBase *h, HashmapBase *other) { + struct swap_entries swap; + struct hashmap_base_entry *e, *n; + Iterator i; + unsigned idx; + int r; + + assert(h); + + if (!other) + return 0; + + assert(other->type == h->type); + + /* + * This reserves buckets for the worst case, where none of other's + * entries are yet present in h. This is preferable to risking + * an allocation failure in the middle of the moving and having to + * rollback or return a partial result. + */ + r = resize_buckets(h, n_entries(other)); + if (r < 0) + return r; + + HASHMAP_FOREACH_IDX(idx, other, i) { + unsigned h_hash; + + e = bucket_at(other, idx); + h_hash = bucket_hash(h, e->key); + if (bucket_scan(h, h_hash, e->key) != IDX_NIL) + continue; + + n = &bucket_at_swap(&swap, IDX_PUT)->p.b; + n->key = e->key; + if (h->type != HASHMAP_TYPE_SET) + ((struct plain_hashmap_entry*) n)->value = + ((struct plain_hashmap_entry*) e)->value; + assert_se(hashmap_put_boldly(h, h_hash, &swap, false) == 1); + + remove_entry(other, idx); + } + + return 0; +} + +int internal_hashmap_move_one(HashmapBase *h, HashmapBase *other, const void *key) { + struct swap_entries swap; + unsigned h_hash, other_hash, idx; + struct hashmap_base_entry *e, *n; + int r; + + assert(h); + + h_hash = bucket_hash(h, key); + if (bucket_scan(h, h_hash, key) != IDX_NIL) + return -EEXIST; + + if (!other) + return -ENOENT; + + assert(other->type == h->type); + + other_hash = bucket_hash(other, key); + idx = bucket_scan(other, other_hash, key); + if (idx == IDX_NIL) + return -ENOENT; + + e = bucket_at(other, idx); + + n = &bucket_at_swap(&swap, IDX_PUT)->p.b; + n->key = e->key; + if (h->type != HASHMAP_TYPE_SET) + ((struct plain_hashmap_entry*) n)->value = + ((struct plain_hashmap_entry*) e)->value; + r = hashmap_put_boldly(h, h_hash, &swap, true); + if (r < 0) + return r; + + remove_entry(other, idx); + return 0; +} + +HashmapBase *internal_hashmap_copy(HashmapBase *h) { + HashmapBase *copy; + int r; + + assert(h); + + copy = hashmap_base_new(h->hash_ops, h->type HASHMAP_DEBUG_SRC_ARGS); + if (!copy) + return NULL; + + switch (h->type) { + case HASHMAP_TYPE_PLAIN: + case HASHMAP_TYPE_ORDERED: + r = hashmap_merge((Hashmap*)copy, (Hashmap*)h); + break; + case HASHMAP_TYPE_SET: + r = set_merge((Set*)copy, (Set*)h); + break; + default: + assert_not_reached("Unknown hashmap type"); + } + + if (r < 0) { + internal_hashmap_free(copy); + return NULL; + } + + return copy; +} + +char **internal_hashmap_get_strv(HashmapBase *h) { + char **sv; + Iterator i; + unsigned idx, n; + + sv = new(char*, n_entries(h)+1); + if (!sv) + return NULL; + + n = 0; + HASHMAP_FOREACH_IDX(idx, h, i) + sv[n++] = entry_value(h, bucket_at(h, idx)); + sv[n] = NULL; + + return sv; +} + +void *ordered_hashmap_next(OrderedHashmap *h, const void *key) { + struct ordered_hashmap_entry *e; + unsigned hash, idx; + + assert(key); + + if (!h) + return NULL; + + hash = bucket_hash(h, key); + idx = bucket_scan(h, hash, key); + if (idx == IDX_NIL) + return NULL; + + e = ordered_bucket_at(h, idx); + if (e->iterate_next == IDX_NIL) + return NULL; + return ordered_bucket_at(h, e->iterate_next)->p.value; +} + +int set_consume(Set *s, void *value) { + int r; + + r = set_put(s, value); + if (r <= 0) + free(value); + + return r; +} + +int set_put_strdup(Set *s, const char *p) { + char *c; + int r; + + assert(s); + assert(p); + + c = strdup(p); + if (!c) + return -ENOMEM; + + r = set_consume(s, c); + if (r == -EEXIST) + return 0; + + return r; +} + +int set_put_strdupv(Set *s, char **l) { + int n = 0, r; + char **i; + + STRV_FOREACH(i, l) { + r = set_put_strdup(s, *i); + if (r < 0) + return r; + + n += r; + } + + return n; +} |