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343
src/hashmap.c
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343
src/hashmap.c
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#include <bh/internal/hashmap.h>
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#include <stdlib.h>
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#include <string.h>
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bh_hashmap_t *bh_hashmap_new(bh_equal_cb_t equal,
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bh_hash_cb_t hash)
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{
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bh_hashmap_t *result;
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result = malloc(sizeof(*result));
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if (result)
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bh_hashmap_init(result, equal, hash);
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return result;
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}
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void bh_hashmap_free(bh_hashmap_t *hashmap)
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{
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bh_hashmap_destroy(hashmap);
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free(hashmap);
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}
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void bh_hashmap_init(bh_hashmap_t *hashmap,
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bh_equal_cb_t equal,
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bh_hash_cb_t hash)
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{
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memset(hashmap, 0, sizeof(*hashmap));
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hashmap->factor = 0.75f;
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hashmap->equal = equal;
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hashmap->hash = hash;
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}
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void bh_hashmap_destroy(bh_hashmap_t *hashmap)
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{
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if (hashmap->capacity)
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{
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free(hashmap->data);
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free(hashmap->psls);
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}
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}
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void bh_hashmap_clear(bh_hashmap_t *hashmap)
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{
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if (hashmap->capacity)
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memset(hashmap->psls, 0, hashmap->capacity * sizeof(size_t));
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hashmap->size = 0;
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}
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int bh_hashmap_reserve(bh_hashmap_t *hashmap,
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size_t size)
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{
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bh_hashmap_t other;
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size_t capacity, max_capacity, threshold;
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/* Calculate hashmap max capacity and capacity threshold */
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capacity = hashmap->capacity;
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threshold = hashmap->capacity * hashmap->factor;
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max_capacity = ((size_t)-1) / sizeof(bh_hashmap_node_t);
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/* New capacity can't be smaller then current hashmap size */
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if (size < hashmap->size)
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size = hashmap->size;
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/* Find new hashmap capacity */
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if (!size)
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{
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/* No capacity needed */
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capacity = 0;
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threshold = 0;
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}
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else if (size > threshold)
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{
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/* Bigger capacity needed - grow the hashmap */
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while (size > threshold)
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{
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capacity = (capacity) ? (capacity * 2) : (16);
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threshold = capacity * hashmap->factor;
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/* Capacity can't be bigger than max capacity and overflow */
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if (capacity > max_capacity || capacity < 16)
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return -1;
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}
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}
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else
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{
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/* Smaller capacity needed - shrink the hashmap */
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while (size <= threshold / 2 && capacity > 16)
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{
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capacity /= 2;
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threshold = capacity * hashmap->factor;
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}
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}
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/* Prevent same size reallocation */
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if (capacity == hashmap->capacity)
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return 0;
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/* Initialize new hashmap */
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bh_hashmap_init(&other, hashmap->equal, hashmap->hash);
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other.factor = hashmap->factor;
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if (capacity)
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{
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void *iter;
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/* Allocate new memory for the hashmap */
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other.data = malloc(sizeof(*other.data) * capacity);
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other.psls = malloc(sizeof(size_t) * capacity);
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other.threshold = threshold;
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other.capacity = capacity;
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/* Check for allocations failure */
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if (!other.data || !other.psls)
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{
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if (other.data)
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free(other.data);
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if (other.psls)
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free(other.psls);
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return -1;
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}
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/* Reset probe sequence lengths */
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memset(other.psls, 0, sizeof(size_t) * other.capacity);
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/* Iterate and insert data into hashmap */
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iter = bh_hashmap_iter_next(hashmap, NULL);
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while (iter)
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{
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void *key, *value;
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key = bh_hashmap_iter_key(iter);
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value = bh_hashmap_iter_value(iter);
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bh_hashmap_insert(&other, key, value);
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iter = bh_hashmap_iter_next(hashmap, iter);
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}
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}
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/* Swap hashmaps */
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bh_hashmap_destroy(hashmap);
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*hashmap = other;
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return 0;
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}
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int bh_hashmap_insert(bh_hashmap_t *hashmap,
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void *key,
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void *value)
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{
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size_t bucket, psl, tmp_psl;
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bh_hashmap_node_t item, tmp;
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/* Try to stay below hashmap threshold */
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if (hashmap->size + 1 > hashmap->threshold)
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if (bh_hashmap_reserve(hashmap, hashmap->size + 1))
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if (hashmap->size >= hashmap->capacity)
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return -1;
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/* Prepare inserted data and set PSL to 1 */
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item.key = key;
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item.value = value;
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psl = 1;
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/* Calculate prefered bucket index */
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bucket = hashmap->hash(key) & (hashmap->capacity - 1);
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/* Find empty bucket */
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while (hashmap->psls[bucket])
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{
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/* Current bucket is richer then us - swap elements */
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if (psl > hashmap->psls[bucket])
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{
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tmp = hashmap->data[bucket];
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tmp_psl = hashmap->psls[bucket];
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hashmap->data[bucket] = item;
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hashmap->psls[bucket] = psl;
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item = tmp;
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psl = tmp_psl;
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}
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bucket = (bucket + 1) & (hashmap->capacity - 1);
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psl++;
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}
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/* Found empty bucket - place item here */
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hashmap->data[bucket] = item;
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hashmap->psls[bucket] = psl;
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hashmap->size++;
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return 0;
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}
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void bh_hashmap_remove(bh_hashmap_t *hashmap,
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void *key)
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{
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void *iter;
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iter = bh_hashmap_iter_at(hashmap, key);
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if (iter)
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bh_hashmap_iter_remove(hashmap, iter);
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}
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void *bh_hashmap_at(bh_hashmap_t *hashmap,
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void *key,
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int *exists)
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{
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void *iter;
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iter = bh_hashmap_iter_at(hashmap, key);
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if (iter)
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{
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/* If exists flag passed - set to 1 */
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if (exists)
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*exists = 1;
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return bh_hashmap_iter_value(iter);
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}
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/* If exists flag passed - set to 0 */
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if (exists)
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*exists = 0;
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return NULL;
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}
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int bh_hashmap_empty(bh_hashmap_t *hashmap)
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{
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return !hashmap->size;
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}
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size_t bh_hashmap_size(bh_hashmap_t *hashmap)
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{
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return hashmap->size;
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}
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size_t bh_hashmap_capacity(bh_hashmap_t *hashmap)
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{
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return hashmap->capacity;
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}
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float bh_hashmap_factor(bh_hashmap_t *hashmap)
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{
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return hashmap->factor;
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}
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void bh_hashmap_set_factor(bh_hashmap_t *hashmap,
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float factor)
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{
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factor = (factor > 1.0f) ? (1.0f) : (factor);
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factor = (factor < 0.15f) ? (0.15f) : (factor);
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hashmap->factor = factor;
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hashmap->threshold = hashmap->capacity * factor;
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}
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void *bh_hashmap_iter_at(bh_hashmap_t *hashmap,
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void *key)
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{
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size_t bucket, psl;
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/* Nothing can be in empty map */
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if (!hashmap->size)
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return NULL;
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/* Calculate prefered bucket index and set PSL to 1 */
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bucket = hashmap->hash(key) & (hashmap->capacity - 1);
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psl = 1;
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/* Iterate hashmap until we find element or find richer bucket */
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while (hashmap->psls[bucket] >= psl && hashmap->equal(hashmap->data[bucket].key, key))
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{
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bucket = (bucket + 1) & (hashmap->capacity - 1);
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psl++;
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}
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/* If bucket is poorer or equal to us - we found our element */
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if (hashmap->psls[bucket] >= psl)
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return hashmap->data + bucket;
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return NULL;
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}
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void *bh_hashmap_iter_next(bh_hashmap_t *hashmap,
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void *iter)
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{
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bh_hashmap_node_t *item;
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item = (bh_hashmap_node_t *)iter;
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while (1)
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{
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/* Advance or set iterator to the first element */
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if (item)
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item++;
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else
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item = hashmap->data;
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/* Check iterator for validity */
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if (item >= hashmap->data + hashmap->capacity)
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return NULL;
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/* Check iterator's item PSL */
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if (hashmap->psls[item - hashmap->data])
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return item;
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}
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}
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void bh_hashmap_iter_remove(bh_hashmap_t *hashmap,
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void *iter)
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{
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size_t bucket, next_bucket;
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/* Check if hashmap is empty or we are given NULL iterator */
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if (!iter || !hashmap->size)
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return;
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/* Adjust hashmap size, calculate current and next bucket index */
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hashmap->size--;
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bucket = (bh_hashmap_node_t *)iter - hashmap->data;
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next_bucket = (bucket + 1) & (hashmap->capacity - 1);
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/* Shift all elements toward their preffered place */
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while (hashmap->psls[next_bucket] > 1)
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{
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/* Copy item and adjust PSL */
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hashmap->data[bucket] = hashmap->data[next_bucket];
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hashmap->psls[bucket] = hashmap->psls[next_bucket] - 1;
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/* Calculate next bucket index */
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bucket = next_bucket;
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next_bucket = (bucket + 1) & (hashmap->capacity - 1);
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}
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/* Reset bucket's PSL (mark empty) */
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hashmap->psls[bucket] = 0;
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}
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void *bh_hashmap_iter_key(void *iter)
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{
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return ((bh_hashmap_node_t *)iter)->key;
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}
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void *bh_hashmap_iter_value(void *iter)
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{
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return ((bh_hashmap_node_t *)iter)->value;
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}
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