Initial commit

1 files changed, 343 insertions, 0 deletions

diff --git a/src/hashmap.c b/src/hashmap.c
new file mode 100644
index 0000000..c9fb315
--- /dev/null
+++ b/src/hashmap.c
@@ -0,0 +1,343 @@
+#include <bh/internal/hashmap.h>
+#include <stdlib.h>
+#include <string.h>
+
+bh_hashmap_t *bh_hashmap_new(bh_equal_cb_t equal,
+                             bh_hash_cb_t hash)
+{
+    bh_hashmap_t *result;
+
+    result = malloc(sizeof(*result));
+    if (result)
+        bh_hashmap_init(result, equal, hash);
+
+    return result;
+}
+
+void bh_hashmap_free(bh_hashmap_t *hashmap)
+{
+    bh_hashmap_destroy(hashmap);
+    free(hashmap);
+}
+
+void bh_hashmap_init(bh_hashmap_t *hashmap,
+                     bh_equal_cb_t equal,
+                     bh_hash_cb_t hash)
+{
+    memset(hashmap, 0, sizeof(*hashmap));
+    hashmap->factor = 0.75f;
+    hashmap->equal = equal;
+    hashmap->hash = hash;
+}
+
+void bh_hashmap_destroy(bh_hashmap_t *hashmap)
+{
+    if (hashmap->capacity)
+    {
+        free(hashmap->data);
+        free(hashmap->psls);
+    }
+}
+
+void bh_hashmap_clear(bh_hashmap_t *hashmap)
+{
+    if (hashmap->capacity)
+        memset(hashmap->psls, 0, hashmap->capacity * sizeof(size_t));
+    hashmap->size = 0;
+}
+
+int bh_hashmap_reserve(bh_hashmap_t *hashmap,
+                        size_t size)
+{
+    bh_hashmap_t other;
+    size_t capacity, max_capacity, threshold;
+
+    /* Calculate hashmap max capacity and capacity threshold */
+    capacity = hashmap->capacity;
+    threshold = hashmap->capacity * hashmap->factor;
+    max_capacity = ((size_t)-1) / sizeof(bh_hashmap_node_t);
+
+    /* New capacity can't be smaller then current hashmap size */
+    if (size < hashmap->size)
+        size = hashmap->size;
+
+    /* Find new hashmap capacity */
+    if (!size)
+    {
+        /* No capacity needed */
+        capacity = 0;
+        threshold = 0;
+    }
+    else if (size > threshold)
+    {
+        /* Bigger capacity needed - grow the hashmap */
+        while (size > threshold)
+        {
+            capacity = (capacity) ? (capacity * 2) : (16);
+            threshold = capacity * hashmap->factor;
+
+            /* Capacity can't be bigger than max capacity and overflow */
+            if (capacity > max_capacity || capacity < 16)
+                return -1;
+        }
+    }
+    else
+    {
+        /* Smaller capacity needed - shrink the hashmap */
+        while (size <= threshold / 2 && capacity > 16)
+        {
+            capacity /= 2;
+            threshold = capacity * hashmap->factor;
+        }
+    }
+
+    /* Prevent same size reallocation */
+    if (capacity == hashmap->capacity)
+        return 0;
+
+    /* Initialize new hashmap */
+    bh_hashmap_init(&other, hashmap->equal, hashmap->hash);
+    other.factor = hashmap->factor;
+
+    if (capacity)
+    {
+        void *iter;
+
+        /* Allocate new memory for the hashmap */
+        other.data = malloc(sizeof(*other.data) * capacity);
+
+        other.psls = malloc(sizeof(size_t) * capacity);
+        other.threshold = threshold;
+        other.capacity = capacity;
+
+        /* Check for allocations failure */
+        if (!other.data || !other.psls)
+        {
+            if (other.data)
+                free(other.data);
+            if (other.psls)
+                free(other.psls);
+            return -1;
+        }
+
+        /* Reset probe sequence lengths */
+        memset(other.psls, 0, sizeof(size_t) * other.capacity);
+
+        /* Iterate and insert data into hashmap */
+        iter = bh_hashmap_iter_next(hashmap, NULL);
+        while (iter)
+        {
+            void *key, *value;
+
+            key = bh_hashmap_iter_key(iter);
+            value = bh_hashmap_iter_value(iter);
+            bh_hashmap_insert(&other, key, value);
+
+            iter = bh_hashmap_iter_next(hashmap, iter);
+        }
+    }
+
+    /* Swap hashmaps */
+    bh_hashmap_destroy(hashmap);
+    *hashmap = other;
+    return 0;
+}
+
+int bh_hashmap_insert(bh_hashmap_t *hashmap,
+                      void *key,
+                      void *value)
+{
+    size_t bucket, psl, tmp_psl;
+    bh_hashmap_node_t item, tmp;
+
+    /* Try to stay below hashmap threshold */
+    if (hashmap->size + 1 > hashmap->threshold)
+        if (bh_hashmap_reserve(hashmap, hashmap->size + 1))
+            if (hashmap->size >= hashmap->capacity)
+                return -1;
+
+    /* Prepare inserted data and set PSL to 1 */
+    item.key = key;
+    item.value = value;
+    psl = 1;
+
+    /* Calculate prefered bucket index */
+    bucket = hashmap->hash(key) & (hashmap->capacity - 1);
+
+    /* Find empty bucket */
+    while (hashmap->psls[bucket])
+    {
+        /* Current bucket is richer then us - swap elements */
+        if (psl > hashmap->psls[bucket])
+        {
+            tmp = hashmap->data[bucket];
+            tmp_psl = hashmap->psls[bucket];
+            hashmap->data[bucket] = item;
+            hashmap->psls[bucket] = psl;
+            item = tmp;
+            psl = tmp_psl;
+        }
+
+        bucket = (bucket + 1) & (hashmap->capacity - 1);
+        psl++;
+    }
+
+    /* Found empty bucket - place item here */
+    hashmap->data[bucket] = item;
+    hashmap->psls[bucket] = psl;
+    hashmap->size++;
+
+    return 0;
+}
+
+void bh_hashmap_remove(bh_hashmap_t *hashmap,
+                       void *key)
+{
+    void *iter;
+
+    iter = bh_hashmap_iter_at(hashmap, key);
+    if (iter)
+        bh_hashmap_iter_remove(hashmap, iter);
+}
+
+void *bh_hashmap_at(bh_hashmap_t *hashmap,
+                    void *key,
+                    int *exists)
+{
+    void *iter;
+
+    iter = bh_hashmap_iter_at(hashmap, key);
+    if (iter)
+    {
+        /* If exists flag passed - set to 1 */
+        if (exists)
+            *exists = 1;
+        return bh_hashmap_iter_value(iter);
+    }
+
+    /* If exists flag passed - set to 0 */
+    if (exists)
+        *exists = 0;
+    return NULL;
+}
+
+int bh_hashmap_empty(bh_hashmap_t *hashmap)
+{
+    return !hashmap->size;
+}
+
+size_t bh_hashmap_size(bh_hashmap_t *hashmap)
+{
+    return hashmap->size;
+}
+
+size_t bh_hashmap_capacity(bh_hashmap_t *hashmap)
+{
+    return hashmap->capacity;
+}
+
+float bh_hashmap_factor(bh_hashmap_t *hashmap)
+{
+    return hashmap->factor;
+}
+
+void bh_hashmap_set_factor(bh_hashmap_t *hashmap,
+                           float factor)
+{
+    factor = (factor > 1.0f) ? (1.0f) : (factor);
+    factor = (factor < 0.15f) ? (0.15f) : (factor);
+
+    hashmap->factor = factor;
+    hashmap->threshold = hashmap->capacity * factor;
+}
+
+void *bh_hashmap_iter_at(bh_hashmap_t *hashmap,
+                         void *key)
+{
+    size_t bucket, psl;
+
+    /* Nothing can be in empty map */
+    if (!hashmap->size)
+        return NULL;
+
+    /* Calculate prefered bucket index and set PSL to 1 */
+    bucket = hashmap->hash(key) & (hashmap->capacity - 1);
+    psl = 1;
+
+    /* Iterate hashmap until we find element or find richer bucket */
+    while (hashmap->psls[bucket] >= psl && hashmap->equal(hashmap->data[bucket].key, key))
+    {
+        bucket = (bucket + 1) & (hashmap->capacity - 1);
+        psl++;
+    }
+
+    /* If bucket is poorer or equal to us - we found our element */
+    if (hashmap->psls[bucket] >= psl)
+        return hashmap->data + bucket;
+
+    return NULL;
+}
+
+void *bh_hashmap_iter_next(bh_hashmap_t *hashmap,
+                           void *iter)
+{
+    bh_hashmap_node_t *item;
+
+    item = (bh_hashmap_node_t *)iter;
+    while (1)
+    {
+        /* Advance or set iterator to the first element */
+        if (item)
+            item++;
+        else
+            item = hashmap->data;
+
+        /* Check iterator for validity */
+        if (item >= hashmap->data + hashmap->capacity)
+            return NULL;
+
+        /* Check iterator's item PSL */
+        if (hashmap->psls[item - hashmap->data])
+            return item;
+    }
+}
+
+void bh_hashmap_iter_remove(bh_hashmap_t *hashmap,
+                            void *iter)
+{
+    size_t bucket, next_bucket;
+
+    /* Check if hashmap is empty or we are given NULL iterator */
+    if (!iter || !hashmap->size)
+        return;
+
+    /* Adjust hashmap size, calculate current and next bucket index */
+    hashmap->size--;
+    bucket = (bh_hashmap_node_t *)iter - hashmap->data;
+    next_bucket = (bucket + 1) & (hashmap->capacity - 1);
+
+    /* Shift all elements toward their preffered place */
+    while (hashmap->psls[next_bucket] > 1)
+    {
+        /* Copy item and adjust PSL */
+        hashmap->data[bucket] = hashmap->data[next_bucket];
+        hashmap->psls[bucket] = hashmap->psls[next_bucket] - 1;
+
+        /* Calculate next bucket index */
+        bucket = next_bucket;
+        next_bucket = (bucket + 1) & (hashmap->capacity - 1);
+    }
+
+    /* Reset bucket's PSL (mark empty) */
+    hashmap->psls[bucket] = 0;
+}
+
+void *bh_hashmap_iter_key(void *iter)
+{
+    return ((bh_hashmap_node_t *)iter)->key;
+}
+
+void *bh_hashmap_iter_value(void *iter)
+{
+    return ((bh_hashmap_node_t *)iter)->value;
+}