1 files changed, 390 insertions, 0 deletions

diff --git a/src/Hashmap.c b/src/Hashmap.c
new file mode 100755
index 0000000..ad8e7bd
--- /dev/null
+++ b/src/Hashmap.c
@@ -0,0 +1,390 @@
+#include <BH/Hashmap.h>
+#include <stdlib.h>
+#include <string.h>
+
+
+typedef struct BH_HashmapNode
+{
+    void *key;
+    void *value;
+} BH_HashmapNode;
+
+
+struct BH_Hashmap
+{
+    BH_HashmapNode *data;
+    size_t *psls;
+    size_t size;
+    size_t capacity;
+    size_t threshold;
+    BH_EqualCallback equal;
+    BH_HashCallback hash;
+    float factor;
+};
+
+
+static void BH_HashmapInit(BH_Hashmap *hashmap,
+                           BH_EqualCallback equal,
+                           BH_HashCallback hash)
+{
+    memset(hashmap, 0, sizeof(*hashmap));
+    hashmap->factor = 0.75f;
+    hashmap->equal = equal;
+    hashmap->hash = hash;
+}
+
+
+static void BH_HashmapDestroy(BH_Hashmap *hashmap)
+{
+    if (hashmap->capacity)
+    {
+        free(hashmap->data);
+        free(hashmap->psls);
+    }
+}
+
+
+static int BH_CalcCapacity(size_t size,
+                           float factor,
+                           size_t *capacity,
+                           size_t *threshold)
+{
+    /* Check if we need any capacity at all */
+    if (!size)
+    {
+        *capacity = 0;
+        *threshold = 0;
+        return BH_OK;
+    }
+
+    /* Calculate nearest power of 2 capacity */
+    *capacity = 16;
+    *threshold = *capacity * factor;
+    while (size > *threshold)
+    {
+        *capacity *= 2;
+        *threshold = *capacity * factor;
+
+        /* Catch capacity overflow  */
+        if (*capacity < 16)
+            return BH_OOM;
+    }
+
+    /* Catch malloc overflow */
+    if (*capacity >= ((size_t)-1) / sizeof(BH_HashmapNode))
+        return BH_OOM;
+
+    return BH_OK;
+}
+
+
+static void BH_CopyHashmap(BH_Hashmap *dest,
+                           BH_Hashmap *src)
+{
+    void *iter;
+
+    /* Iterate and insert data into hashmap */
+    iter = BH_HashmapIterNext(src, NULL);
+    while (iter)
+    {
+        void *key, *value;
+
+        key = BH_HashmapIterKey(iter);
+        value = BH_HashmapIterValue(iter);
+        BH_HashmapInsert(dest, key, value);
+
+        iter = BH_HashmapIterNext(src, iter);
+    }
+}
+
+
+BH_Hashmap *BH_HashmapNew(BH_EqualCallback equal,
+                          BH_HashCallback hash)
+{
+    BH_Hashmap *result;
+
+    result = malloc(sizeof(*result));
+    if (result)
+        BH_HashmapInit(result, equal, hash);
+
+    return result;
+}
+
+
+void BH_HashmapFree(BH_Hashmap *hashmap)
+{
+    BH_HashmapDestroy(hashmap);
+    free(hashmap);
+}
+
+
+void BH_HashmapClear(BH_Hashmap *hashmap)
+{
+    if (hashmap->capacity)
+        memset(hashmap->psls, 0, hashmap->capacity * sizeof(size_t));
+    hashmap->size = 0;
+}
+
+
+int BH_HashmapReserve(BH_Hashmap *hashmap,
+                      size_t size)
+{
+    BH_Hashmap other;
+    size_t capacity, threshold;
+
+    /* New capacity can't be smaller then current hashmap size */
+    if (size < hashmap->size)
+        size = hashmap->size;
+
+    /* Calculate new capacity */
+    if (BH_CalcCapacity(size, hashmap->factor, &capacity, &threshold))
+        return BH_OOM;
+
+    /* Prevent same size reallocation */
+    if (capacity == hashmap->capacity)
+        return BH_OK;
+
+    /* Initialize new hashmap */
+    BH_HashmapInit(&other, hashmap->equal, hashmap->hash);
+    other.factor = hashmap->factor;
+
+    if (capacity)
+    {
+        /* 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 BH_OOM;
+        }
+
+        /* Reset probe sequence lengths */
+        memset(other.psls, 0, sizeof(size_t) * other.capacity);
+
+        /* Copy data from old hashmap to the new hashmap */
+        BH_CopyHashmap(&other, hashmap);
+    }
+
+    /* Swap hashmaps */
+    BH_HashmapDestroy(hashmap);
+    *hashmap = other;
+    return BH_OK;
+}
+
+
+int BH_HashmapInsert(BH_Hashmap *hashmap,
+                     void *key,
+                     void *value)
+{
+    size_t bucket, psl, tmp_psl;
+    BH_HashmapNode item, tmp;
+
+    /* Try to stay below hashmap threshold */
+    if (hashmap->size + 1 > hashmap->threshold)
+        if (BH_HashmapReserve(hashmap, hashmap->size + 1))
+            if (hashmap->size >= hashmap->capacity)
+                return BH_OOM;
+
+    /* 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 BH_OK;
+}
+
+
+void BH_HashmapRemove(BH_Hashmap *hashmap,
+                      void *key)
+{
+    void *iter;
+
+    iter = BH_HashmapIterAt(hashmap, key);
+    if (iter)
+        BH_HashmapIterRemove(hashmap, iter);
+}
+
+
+int BH_HashmapAt(BH_Hashmap *hashmap,
+                 void *key,
+                 void **value)
+{
+    void *iter;
+    iter = BH_HashmapIterAt(hashmap, key);
+
+    if (!iter)
+        return BH_NOTFOUND;
+
+    if (value)
+        *value = BH_HashmapIterValue(iter);
+
+    return BH_OK;
+}
+
+
+int BH_HashmapEmpty(BH_Hashmap *hashmap)
+{
+    return !hashmap->size;
+}
+
+
+size_t BH_HashmapSize(BH_Hashmap *hashmap)
+{
+    return hashmap->size;
+}
+
+
+size_t BH_HashmapCapacity(BH_Hashmap *hashmap)
+{
+    return hashmap->capacity;
+}
+
+
+float BH_HashmapFactor(BH_Hashmap *hashmap)
+{
+    return hashmap->factor;
+}
+
+
+void BH_HashmapSetFactor(BH_Hashmap *hashmap,
+                         float factor)
+{
+    /* Limit the factor value to [0.15, 1.0] */
+    factor = (factor > 1.0f) ? (1.0f) : (factor);
+    factor = (factor < 0.15f) ? (0.15f) : (factor);
+
+    /* Calculate new threshold value */
+    hashmap->factor = factor;
+    hashmap->threshold = hashmap->capacity * factor;
+}
+
+
+void *BH_HashmapIterAt(BH_Hashmap *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_HashmapIterNext(BH_Hashmap *hashmap,
+                         void *iter)
+{
+    BH_HashmapNode *item;
+
+    item = (BH_HashmapNode *)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_HashmapIterRemove(BH_Hashmap *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_HashmapNode *)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_HashmapIterKey(void *iter)
+{
+    return ((BH_HashmapNode *)iter)->key;
+}
+
+
+void *BH_HashmapIterValue(void *iter)
+{
+    return ((BH_HashmapNode *)iter)->value;
+}
+