1 files changed, 337 insertions, 0 deletions
diff --git a/src/hamt.c b/src/hamt.c
new file mode 100644
index 0000000..a6be3ba
--- /dev/null
+++ b/src/hamt.c
@@ -0,0 +1,337 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <string.h>
+#include <assert.h>
+#include "hamt.h"
+
+#include "mempool.h"
+MEMPOOL_GENERATE(hamt, struct hamt, 16)
+MEMPOOL_GENERATE(hl,   struct hamt_nodelist, 64)
+MEMPOOL_GENERATE(hi,   struct hamt_item, 32)
+
+#define tag_ptr(ptr, tag)   ((uintptr_t)(ptr) | (tag))
+#define untag_ptr(ptr, tag) ((uintptr_t)(ptr) & ~(tag))
+#define is_tagged(ptr, tag) ((uintptr_t)(ptr) & (tag))
+
+#define HAMT_ITEM_TAG 0x1
+#define TAG_NODELIST(ptr) \
+    (hamtptr_t)untag_ptr(ptr, HAMT_ITEM_TAG)
+#define TAG_ITEM(ptr)     \
+    (hamtptr_t)tag_ptr(ptr, HAMT_ITEM_TAG)
+#define AS_NODELIST(ptr) \
+    ((struct hamt_nodelist *)untag_ptr(ptr, HAMT_ITEM_TAG))
+#define AS_ITEM(ptr)     \
+    ((struct hamt_item *)untag_ptr(ptr, HAMT_ITEM_TAG))
+#define AS_VOIDPTR(ptr)  \
+    ((void *)untag_ptr(ptr, HAMT_ITEM_TAG)
+#define IS_NODELIST(hamtptr) \
+    !is_tagged(hamtptr, HAMT_ITEM_TAG)
+#define IS_ITEM(hamtptr)     \
+    is_tagged(hamtptr, HAMT_ITEM_TAG)
+
+#define for_each_item(item, head)                        \
+    for(struct hamt_item *item = (head), *next = NULL;   \
+        item && (next = item->next, 1); item = next)
+
+#define popcount(i) __builtin_popcount(i)
+
+#define BITS 6
+#define BITS_MASK 0x3f
+
+static inline struct hamt_nodelist *hamt_nodelist_alloc(void);
+static inline struct hamt_item *hamt_item_alloc(void);
+
+static void hamtptr_destroy(hamtptr_t hamtptr);
+static inline void hamtptr_add_ref(hamtptr_t hamtptr);
+
+// static void hamt_print_hamtptr(hamtptr_t hamtptr, int depth);
+
+hamt_t hamt_create(hamt_equal_fn equal_fn, hamt_hash_fn hash_fn)
+{
+    // hamt_t hamt = malloc(sizeof(*hamt));
+    hamt_t hamt = hamt_mempool_allocate();
+    hamt->equal_fn = equal_fn;
+    hamt->hash_fn  = hash_fn;
+    hamt->root = TAG_NODELIST(hamt_nodelist_alloc());
+
+    return hamt;
+}
+
+void hamt_destroy(hamt_t hamt)
+{
+    if(!hamt) return;
+
+    hamtptr_destroy(hamt->root);
+    // free(hamt);
+    hamt_mempool_free(hamt);
+}
+
+hamt_t hamt_clone(hamt_t src)
+{
+    // hamt_t hamt = malloc(sizeof(*hamt));
+    hamt_t hamt = hamt_mempool_allocate();
+
+    if(!src) return hamt;
+
+    hamt->equal_fn = src->equal_fn;
+    hamt->hash_fn  = src->hash_fn;
+    hamt->root     = src->root;
+    hamtptr_add_ref(hamt->root);
+
+    return hamt;
+}
+
+static int hamt_find_hamtptr(hamtptr_t root, hamtptr_t *ret, uint32_t *hash)
+{
+    *ret = root;
+
+    for(size_t i = 0; i < sizeof(*hash)*8/BITS; i++) {
+        assert(IS_NODELIST(*ret));
+        struct hamt_nodelist *nodelist = AS_NODELIST(*ret);
+
+        size_t rawidx = *hash & BITS_MASK;
+        if(!(nodelist->bitmask & (1 << rawidx))) {
+            return sizeof(*hash)*8/BITS - i;
+        }
+
+        *hash >>= BITS;
+
+        size_t idx = popcount(nodelist->bitmask & ((1 << rawidx) - 1));
+        *ret = nodelist->list[idx];
+    }
+
+    return 0;
+}
+
+int hamt_get(hamt_t hamt, void *key, void **data)
+{
+    hamtptr_t hamtptr;
+    uint32_t hash = hamt->hash_fn(key);
+
+    if(hamt_find_hamtptr(hamt->root, &hamtptr, &hash) != 0)
+        return 1;
+
+    assert(IS_ITEM(hamtptr));
+    struct hamt_item *item = AS_ITEM(hamtptr);
+
+    while(!hamt->equal_fn(key, item->key)) {
+        if(item->next == NULL) return 1;
+        item = item->next;
+    }
+
+    *data = item->data;
+    return 0;
+}
+
+static hamtptr_t hamt_build(uint32_t hash, size_t iter, struct hamt_item **item)
+{
+      if(iter == 1) {
+        *item = hamt_item_alloc();
+        return TAG_ITEM(*item);
+    }
+
+    hash >>= BITS;
+    size_t next_idx = hash & BITS_MASK;
+
+    hamtptr_t next = hamt_build(hash, iter-1, item);
+
+    struct hamt_nodelist *nodelist = hamt_nodelist_alloc();
+
+    // nodelist->list = &next;
+    nodelist->list = calloc(1, sizeof(*nodelist->list));
+    nodelist->list[0] = next;
+
+    nodelist->bitmask = 1 << next_idx;
+
+    return TAG_NODELIST(nodelist);
+}
+
+static hamtptr_t hamt_insert_hamtptr(hamtptr_t root, hamtptr_t hamtptr, uint32_t hash, hamt_equal_fn equal_fn)
+{
+    if(IS_ITEM(root)) {
+        struct hamt_item *item = AS_ITEM(root);
+
+        if(equal_fn(item->key, AS_ITEM(hamtptr)->key)) {
+            item->refs--;
+            AS_ITEM(hamtptr)->next = item->next;
+            return hamtptr;
+        }
+
+        if(item->next) {
+            hamtptr = hamt_insert_hamtptr(TAG_ITEM(item->next), hamtptr, hash, equal_fn);
+        }
+
+        struct hamt_item *new;
+
+        if(item->refs == 1) {
+            new = item;
+        } else {
+            item->refs--;
+            new = hamt_item_alloc();
+            new->key = item->key;
+            new->data = item->data;
+        }
+
+        new->next = AS_ITEM(hamtptr);
+        return TAG_ITEM(new);
+    }
+
+    struct hamt_nodelist *nodelist = AS_NODELIST(root);
+
+    size_t rawidx = hash & BITS_MASK;
+    size_t idx = popcount(nodelist->bitmask & ((1 << rawidx) - 1));
+
+    size_t list_len = popcount(nodelist->bitmask);
+    size_t newlist_len = list_len;
+
+    if(nodelist->bitmask & (1 << rawidx)) {
+        hamtptr = hamt_insert_hamtptr(nodelist->list[idx], hamtptr, hash >> BITS, equal_fn);
+
+        if(nodelist->refs == 1) {
+            nodelist->list[idx] = hamtptr;
+            return TAG_NODELIST(nodelist);
+        }
+    } else {
+        newlist_len++;
+    }
+
+    hamtptr_t *newlist = calloc(newlist_len, sizeof(*newlist));
+    newlist[idx] = hamtptr;
+
+    for(size_t i = 0; i < idx; i++)
+        newlist[i] = nodelist->list[i];
+
+    if(list_len == newlist_len)
+        for(size_t i = idx+1; i < newlist_len; i++)
+            newlist[i] = nodelist->list[i];
+    else
+        for(size_t i = idx+1; i < newlist_len; i++)
+            newlist[i] = nodelist->list[i-1];
+
+    struct hamt_nodelist *new;
+
+    if(nodelist->refs == 1) {
+        new = nodelist;
+        free(nodelist->list);
+    } else {
+        nodelist->refs--;
+        new = hamt_nodelist_alloc();
+    }
+
+    new->list = newlist;
+    new->bitmask = nodelist->bitmask | (1 << rawidx);
+    return TAG_NODELIST(new);
+}
+
+int hamt_set(hamt_t hamt, void *key, void *data, void **keyptr, void **prevdata)
+{
+    hamtptr_t hamtptr;
+    uint32_t hash = hamt->hash_fn(key);
+    uint32_t hash_cpy = hash;
+
+    size_t iter;
+    if((iter = hamt_find_hamtptr(hamt->root, &hamtptr, &hash_cpy)) != 0) {
+        struct hamt_item *item;
+        hamtptr_t new = hamt_build(hash_cpy, iter, &item);
+
+        hamt->root = hamt_insert_hamtptr(hamt->root, new, hash, hamt->equal_fn);
+
+        item->key = key;
+        item->data = data;
+        return 0;
+    }
+
+    assert(IS_ITEM(hamtptr));
+
+    for_each_item(item, AS_ITEM(hamtptr)) {
+        if(hamt->equal_fn(item->key, key)) {
+            if(keyptr)   *keyptr   = item->key;
+            if(prevdata) *prevdata = item->data;
+            if(item->refs == 1) {
+                item->data = data;
+                return 0;
+            }
+
+            key = item->key;
+            break;
+        }
+    }
+
+    struct hamt_item *new = hamt_item_alloc();
+    new->key = key;
+    new->data = data;
+
+    hamt->root = hamt_insert_hamtptr(hamt->root, TAG_ITEM(new), hash, hamt->equal_fn);
+    return 0;
+}
+
+static inline struct hamt_nodelist *hamt_nodelist_alloc(void)
+{
+    // struct hamt_nodelist *nodelist = malloc(sizeof(*nodelist));
+    struct hamt_nodelist *nodelist = hl_mempool_allocate();
+    nodelist->refs = 1;
+    nodelist->list = 0;
+    nodelist->bitmask = 0;
+    return nodelist;
+}
+
+static inline struct hamt_item *hamt_item_alloc(void)
+{
+    // struct hamt_item *item = malloc(sizeof(*item));
+    struct hamt_item *item = hi_mempool_allocate();
+    item->refs = 1;
+    item->key = NULL;
+    item->data = NULL;
+    item->next = NULL;
+    return item;
+}
+
+static inline void hamtptr_destroy(hamtptr_t hamtptr)
+{
+    if(IS_NODELIST(hamtptr)) {
+        struct hamt_nodelist *nodelist = AS_NODELIST(hamtptr);
+
+        for(size_t i = 0; i < popcount(nodelist->bitmask); i++)
+            hamtptr_destroy(nodelist->list[i]);
+
+        if(--nodelist->refs == 0) {
+            free(nodelist->list);
+            // free(nodelist);
+            hl_mempool_free(nodelist);
+        }
+    } else {
+        for_each_item(item, AS_ITEM(hamtptr))
+            if(--item->refs == 0)
+                hi_mempool_free(item);
+                // free(item);
+    }
+}
+
+static inline void hamtptr_add_ref(hamtptr_t hamtptr)
+{
+    if(IS_NODELIST(hamtptr)) {
+        for(size_t i = 0; i < popcount(AS_NODELIST(hamtptr)->bitmask); i++)
+            hamtptr_add_ref(AS_NODELIST(hamtptr)->list[i]);
+        AS_NODELIST(hamtptr)->refs++;
+    } else {
+        for_each_item(item, AS_ITEM(hamtptr))
+            item->refs++;
+    }
+}
+
+// static void hamt_print_hamtptr(hamtptr_t hamtptr, int depth)
+// {
+//     for(int i = 0; i < depth; i++) printf("  ");
+
+//     if(IS_NODELIST(hamtptr)) {
+//         printf("%d, MASK %b\n", AS_NODELIST(hamtptr)->refs, AS_NODELIST(hamtptr)->bitmask);
+//         for(size_t i = 0; i < popcount(AS_NODELIST(hamtptr)->bitmask); i++) {
+//             hamt_print_hamtptr(AS_NODELIST(hamtptr)->list[i], depth+1);
+//         }
+//     } else {
+//         printf("%d, %s: %s\n", AS_ITEM(hamtptr)->refs, (char *)AS_ITEM(hamtptr)->key, (char *)AS_ITEM(hamtptr)->data);
+//         if(AS_ITEM(hamtptr)->next)
+//             hamt_print_hamtptr(TAG_ITEM(AS_ITEM(hamtptr)->next), depth+1);
+//     }
+// }