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/* libmisc/map.c - A map/dict data structure
*
* Copyright (C) 2024-2025 Luke T. Shumaker <lukeshu@lukeshu.com>
* SPDX-License-Identifier: AGPL-3.0-or-later
*/
#include <stdlib.h>
#include <string.h>
#include <libmisc/hash.h>
#include <libmisc/assert.h>
#include <libmisc/map.h>
#define FLAG_ITER (UINT8_C(1)<<0)
#define FLAG_DEL (UINT8_C(1)<<1)
/* Internal utilities *********************************************************/
#define cast(n) lm_dll_node_cast(struct _map_kv, n)
static inline void *_map_kv_keyp(struct _map *m, struct _map_kv *kv) {
assert(m);
assert(kv);
return ((void*)kv)+m->offsetof_k;
}
static inline void *_map_kv_valp(struct _map *m, struct _map_kv *kv) {
assert(m);
assert(kv);
return ((void*)kv)+m->offsetof_v;
}
static inline void _map_lookup(struct _map *m, void *keyp,
hash_t *ret_hash,
lm_dll_root **ret_bucket,
struct _map_kv **ret_kv) {
assert(m);
assert(keyp);
assert(ret_hash);
assert(ret_bucket);
assert(ret_kv);
*ret_hash = hash(keyp, m->sizeof_k);
if (m->nbuckets == 0) {
*ret_bucket = NULL;
*ret_kv = NULL;
return;
}
*ret_bucket = &m->buckets[*ret_hash % m->nbuckets];
for (struct _map_kv *kv = cast((*ret_bucket)->front); kv; kv = cast(kv->rear)) {
if (!(kv->flags & FLAG_DEL) &&
memcmp(_map_kv_keyp(m, kv), keyp, m->sizeof_k) == 0) {
*ret_kv = kv;
return;
}
}
*ret_kv = NULL;
}
static inline void _map_resize(struct _map *m, size_t new_nbuckets) {
assert(m);
assert(new_nbuckets);
lm_dll_root *new_buckets = calloc(new_nbuckets, sizeof(lm_dll_root));
for (size_t i = 0; i < m->nbuckets; i++) {
while (m->buckets[i].front) {
struct _map_kv *kv = cast(m->buckets[i].front);
lm_dll_pop_from_front(&m->buckets[i]);
hash_t h = hash(_map_kv_keyp(m, kv), m->sizeof_k);
lm_dll_push_to_rear(&new_buckets[h % new_nbuckets], kv);
}
}
m->nbuckets = new_nbuckets;
free(m->buckets);
m->buckets = new_buckets;
}
static bool _map_autoresize(struct _map *m) {
assert(m);
if (m->len > (m->nbuckets * 8/10)) {
size_t nbuckets = 1;
while (m->len > (nbuckets * 8/10))
nbuckets <<= 1;
_map_resize(m, nbuckets);
return true;
}
return false;
}
/* Methods ********************************************************************/
void *_map_load(struct _map *m, void *keyp) {
assert(m);
assert(keyp);
hash_t h;
lm_dll_root *bucket;
struct _map_kv *kv;
_map_lookup(m, keyp, &h, &bucket, &kv);
if (!kv)
return NULL;
return _map_kv_valp(m, kv);
}
bool _map_del(struct _map *m, void *keyp) {
assert(m);
assert(keyp);
hash_t h;
lm_dll_root *bucket;
struct _map_kv *kv;
_map_lookup(m, keyp, &h, &bucket, &kv);
if (!kv)
return false;
if (kv->flags & FLAG_ITER) {
kv->flags |= FLAG_DEL;
} else {
lm_dll_remove(bucket, kv);
free(kv);
}
m->len--;
return true;
}
void *_map_store(struct _map *m, void *keyp, void *valp) {
assert(m);
assert(keyp);
assert(valp);
hash_t h;
lm_dll_root *bucket;
struct _map_kv *old;
_map_lookup(m, keyp, &h, &bucket, &old);
if (old) {
lm_dll_remove(bucket, old);
free(old);
m->len--;
}
m->len++;
if (!m->iterating && _map_autoresize(m)) {
h = hash(keyp, m->sizeof_k);
bucket = &m->buckets[h % m->nbuckets];
}
struct _map_kv *kv = calloc(1, m->sizeof_kv);
memcpy(_map_kv_keyp(m, kv), keyp, m->sizeof_k);
memcpy(_map_kv_valp(m, kv), valp, m->sizeof_v);
lm_dll_push_to_rear(bucket, kv);
return _map_kv_valp(m, kv);
}
void _map_free(struct _map *m) {
assert(m);
for (size_t i = 0; i < m->nbuckets; i++) {
while (m->buckets[i].front) {
struct _map_kv *kv = cast(m->buckets[i].front);
lm_dll_pop_from_front(&m->buckets[i]);
free(kv);
}
}
free(m->buckets);
m->len = 0;
m->nbuckets = 0;
m->buckets = NULL;
}
/* Iteration ******************************************************************/
struct _map_iter _map_iter_before(struct _map *m, void *keyp, void **valpp) {
assert(m);
assert(keyp);
assert(valpp);
struct _map_iter state = {
.m = m,
.keyp = keyp,
.valpp = valpp,
};
m->iterating++;
return state;
}
void _map_iter_after(struct _map_iter *state) {
assert(state);
assert(state->m);
state->m->iterating--;
if (!state->m->iterating)
_map_autoresize(state->m);
}
bool _map_iter_next(struct _map_iter *state) {
assert(state);
assert(state->m);
assert(state->valpp);
if (!state->kv) {
if (!state->m->len)
return false;
while (!state->m->buckets[state->i].front)
state->i++;
state->kv = cast(state->m->buckets[state->i].front);
} else {
struct _map_kv *old_kv = state->kv;
state->kv = cast(old_kv->rear);
old_kv->flags &= ~FLAG_ITER;
if (old_kv->flags & FLAG_DEL) {
lm_dll_remove(&state->m->buckets[state->i], old_kv);
free(old_kv);
}
while (!state->kv) {
state->i++;
if (state->i == state->m->nbuckets)
return false;
state->kv = cast(state->m->buckets[state->i].front);
}
}
state->kv->flags |= FLAG_ITER;
memcpy(state->keyp, _map_kv_keyp(state->m, state->kv), state->m->sizeof_k);
*(state->valpp) = _map_kv_valp(state->m, state->kv);
return true;
}
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