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#ifndef MAP_H
#define MAP_H
#include <stdlib.h>
#include <stddef.h>
#include <stdbool.h>
#define NGC_BUCKET_IDX(hash, pow2, bucket) \
((hash) & (((pow2) << (bucket)) - 1))
#ifndef NGC_CONTAINER_OF
#define NGC_CONTAINER_OF(ptr, type, member) \
(type *)((char *)(ptr) - offsetof(type, member))
#endif
/* trait would be something like is_hashable + is_comparable, but that's not yet
* supported so just go with this for now */
typedef map[any K, any D]() {
struct <>_tuple {
K key;
D data;
};
typedef struct <>_tuple *<>_iter;
struct <>_node {
size_t hash;
struct <>_bucket *bucket;
struct <>_tuple t;
};
struct <>_bucket {
size_t size;
struct <>_bucket *next;
struct <>_node nodes[];
};
typedef struct <>_root {
size_t len;
size_t count;
size_t pow2;
struct <>_bucket **buckets;
} <>;
<> <>_create(size_t count)
{
size_t pow2 = 1;
while (pow2 < count)
pow2 <<= 1;
return (<>) {
.len = 0,
.count = 0,
.pow2 = pow2,
.buckets = NULL
};
}
void <>_destroy(<> *root)
{
for (size_t i = 0; i < root->count; ++i)
free(root->buckets[i]);
free(root->buckets);
}
D *<>_insert(<>* root, K key, D data)
{
size_t hash = <key>_hash(&key);
/* look through buckets in order */
for (size_t b = 0; b < root->count; ++b) {
struct <>_bucket *bucket = root->buckets[b];
size_t idx = NGC_BUCKET_IDX(hash, root->pow2, b);
struct <>_node *node = &bucket->nodes[idx];
/* free to use this slot */
if (!node->bucket) {
node->bucket = bucket;
node->hash = hash;
node->t.data = data;
node->t.key = key;
root->len++;
return &node->t.data;
}
/* there already exists a node like this */
if (node->hash == hash && <key>_cmp(&node->t.key, &key) == 0)
return &node->t.data;
}
/* no bucket available, create new one */
size_t size = root->pow2 << root->count;
size_t bytes = sizeof(struct <>_bucket) + sizeof(struct <>_node) * size;
struct <>_bucket *bucket = calloc(1, bytes);
if (!bucket)
return NULL;
bucket->size = size;
size_t buckets_bytes = sizeof(struct <>_bucket *) * (root->count + 1);
struct <>_bucket **new_buckets = realloc(root->buckets, buckets_bytes);
if (!new_buckets) {
free(bucket);
return NULL;
}
root->buckets = new_buckets;
if (root->count != 0)
root->buckets[root->count - 1]->next = bucket;
root->buckets[root->count] = bucket;
/* populate node */
size_t idx = NGC_BUCKET_IDX(hash, root->pow2, root->count);
struct <>_node *node = &bucket->nodes[idx];
node->bucket = bucket;
node->hash = hash;
node->t.key = key;
node->t.data = data;
root->count++;
root->len++;
return &node->t.data;
}
D *<>_find(<> *root, K key)
{
if (root->len == 0)
return NULL;
size_t hash = <key>_hash(&key);
for (size_t b = 0; b < root->count; ++b) {
struct <>_bucket *bucket = root->buckets[b];
size_t idx = NGC_BUCKET_IDX(hash, root->pow2, b);
struct <>_node *node = &bucket->nodes[idx];
if (node->hash != hash)
continue;
if (<key>_cmp(&node->t.key, key) != 0)
continue;
return &node->t.data;
}
return NULL;
}
void <>_remove_found(<> *root, D *data)
{
struct <>_tuple *tuple = NGC_CONTAINER_OF(data, struct <>_tuple, data);
struct <>_node *node = NGC_CONTAINER_OF(tuple, struct <>_node, t);
node->bucket = NULL;
root->len--;
}
void <>_remove(<> *root, K key)
{
D *found = <>_find(root, key);
if (!found)
return;
<>_remove_found(root, found);
}
struct <>_tuple *<>_find_next(struct <>_bucket *bucket, struct <>_tuple *tuple)
{
struct <>_node *node = NGC_CONTAINER_OF(tuple, struct <>_node, t);
size_t idx = node - bucket->nodes;
for (; idx < bucket->size; ++idx) {
struct <>_node *candidate = &bucket->nodes[idx];
if (candidate->bucket)
return &candidate->t;
}
struct <>_bucket *next = bucket->next;
if (!next)
return NULL;
return <>_find_next(next, &next->nodes[0].t);
}
struct <>_tuple *<>_begin(<> *root)
{
if (root->len == 0)
return NULL;
struct <>_bucket *bucket = root->buckets[0];
return <>_find_next(bucket, &bucket->nodes[0].t);
}
struct <>_tuple *<>_next(struct <>_tuple *t)
{
struct <>_node *node = NGC_CONTAINER_OF(t, struct <>_node, t);
return <>_find_next(node->bucket, &(node + 1)->t);
}
bool <>_end(<> *root, struct <>_tuple *t)
{
(void)root;
return t == NULL;
}
size_t <>_len(<> *root)
{
return root->len;
}
};
#endif /* MAP_H */
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