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#include "../../include/std/hash_map.h"
#include "../../include/std/scoped_allocator.h"
#include "../../include/std/mem.h"
#include <assert.h>
/*
Basic hash map implementation. TODO: Improve performance
*/
#define HASH_MAP_INITIAL_SIZE 16
typedef struct HashMapBucketNode HashMapBucketNode;
typedef struct {
HashMapBucketNode *start;
} HashMapBucket;
static void bucket_node_set_next(HashMapBucketNode *self, HashMapBucketNode *next) {
am_memcpy(self, &next, sizeof(next));
}
static HashMapBucketNode* bucket_node_get_next(HashMapBucketNode *self) {
HashMapBucketNode *next;
am_memcpy(&next, self, sizeof(HashMapBucketNode*));
return next;
}
static void bucket_node_set_key(HashMapBucketNode *self, BufferView key) {
u32 key_size;
key_size = (u32)key.size;
am_memcpy((char*)self + sizeof(HashMapBucketNode*), &key_size, sizeof(u32));
am_memcpy((char*)self + sizeof(HashMapBucketNode*) + sizeof(u32), key.data, key_size);
}
static BufferView bucket_node_get_key(HashMapBucketNode *self) {
BufferView key;
u32 key_size;
am_memcpy(&key_size, (char*)self + sizeof(HashMapBucketNode*), sizeof(u32));
key.size = key_size;
key.data = (char*)self + sizeof(HashMapBucketNode*) + sizeof(u32);
return key;
}
static void bucket_node_set_value(HashMapBucketNode *self, void *value, usize type_size) {
u32 key_size;
am_memcpy(&key_size, (char*)self + sizeof(HashMapBucketNode*), sizeof(key_size));
am_memcpy((char*)self + sizeof(HashMapBucketNode*) + sizeof(u32) + key_size, value, type_size);
}
static void* bucket_node_get_value(HashMapBucketNode *self) {
u32 key_size;
void *value;
am_memcpy(&key_size, (char*)self + sizeof(HashMapBucketNode*), sizeof(key_size));
value = (char*)self + sizeof(HashMapBucketNode*) + sizeof(u32) + key_size;
return value;
}
int hash_map_init(HashMap *self, ScopedAllocator *allocator, usize type_size,
HashMapCompare compare_func, HashMapHash hash_func) {
assert(compare_func);
assert(hash_func);
self->allocator = allocator;
self->type_size = type_size;
self->num_elements = 0;
self->compare_func = compare_func;
self->hash_func = hash_func;
return_if_error(buffer_init(&self->buckets, self->allocator));
assert(self->buckets.size == 0);
return_if_error(buffer_append(&self->buckets, NULL, sizeof(HashMapBucket) * HASH_MAP_INITIAL_SIZE));
am_memset(self->buckets.data, 0, self->buckets.size);
return 0;
}
static CHECK_RESULT int hash_map_bucket_add(HashMap *self, HashMapBucket *bucket, BufferView key, void *value) {
HashMapBucketNode *new_bucket_node;
return_if_error(scoped_allocator_alloc(self->allocator,
sizeof(HashMapBucketNode*) + sizeof(u32) + key.size + self->type_size,
(void**)&new_bucket_node));
bucket_node_set_next(new_bucket_node, bucket->start);
bucket_node_set_key(new_bucket_node, key);
bucket_node_set_value(new_bucket_node, value, self->type_size);
bucket->start = new_bucket_node;
return 0;
}
static void hash_map_reorder_buckets(HashMap *self, usize end_index) {
HashMapBucket *bucket;
HashMapBucket *bucket_end;
usize bucket_size;
usize index;
bucket = (HashMapBucket*)self->buckets.data;
bucket_end = ((HashMapBucket*)self->buckets.data) + end_index;
bucket_size = buffer_get_size(&self->buckets, HashMapBucket);
index = 0;
for(; bucket != bucket_end; ++bucket, ++index) {
HashMapBucketNode *prev_bucket_node;
HashMapBucketNode *bucket_node;
prev_bucket_node = NULL;
for(bucket_node = bucket->start; bucket_node; bucket_node_get_next(bucket_node)) {
BufferView bucket_key;
usize bucket_index;
/* Node between current and previous has been removed, chain previous and current */
if(prev_bucket_node && !bucket_node_get_next(prev_bucket_node))
bucket_node_set_next(prev_bucket_node, bucket_node);
bucket_key = bucket_node_get_key(bucket_node);
bucket_index = self->hash_func((const u8*)bucket_key.data, bucket_key.size) % bucket_size;
if(bucket_index != index) {
/* Add node to new bucket */
HashMapBucket *new_bucket;
new_bucket = ((HashMapBucket*)self->buckets.data) + bucket_index;
bucket_node_set_next(bucket_node, new_bucket->start);
new_bucket->start = bucket_node;
/* Mark bucket node to be removed from previous bucket */
bucket_node_set_next(prev_bucket_node, NULL);
} else {
prev_bucket_node = bucket_node;
}
}
}
}
static CHECK_RESULT int hash_map_increase_buckets(HashMap *self) {
usize prev_size;
usize bytes_to_append;
prev_size = buffer_get_size(&self->buckets, HashMapBucket);
bytes_to_append = prev_size * 1.5;
return_if_error(buffer_append(&self->buckets, NULL, bytes_to_append));
am_memset(self->buckets.data + prev_size, 0, prev_size + bytes_to_append);
hash_map_reorder_buckets(self, prev_size);
return 0;
}
int hash_map_insert(HashMap *self, BufferView key, void *value) {
usize bucket_index;
usize bucket_size;
HashMapBucket *bucket;
bucket_size = buffer_get_size(&self->buckets, HashMapBucket);
if(self->num_elements == bucket_size) {
return_if_error(hash_map_increase_buckets(self));
bucket_size = buffer_get_size(&self->buckets, HashMapBucket);
}
bucket_index = self->hash_func((const u8*)key.data, key.size) % bucket_size;
bucket = ((HashMapBucket*)self->buckets.data) + bucket_index;
return_if_error(hash_map_bucket_add(self, bucket, key, value));
++self->num_elements;
return 0;
}
bool hash_map_get(HashMap *self, BufferView key, void *value) {
usize bucket_size;
usize bucket_index;
HashMapBucket *bucket;
HashMapBucketNode *bucket_node;
bucket_size = buffer_get_size(&self->buckets, HashMapBucket);
bucket_index = self->hash_func((const u8*)key.data, key.size) % bucket_size;
bucket = ((HashMapBucket*)self->buckets.data) + bucket_index;
for(bucket_node = bucket->start; bucket_node; bucket_node_get_next(bucket_node)) {
BufferView bucket_key;
bucket_key = bucket_node_get_key(bucket_node);
bucket_index = self->hash_func((const u8*)bucket_key.data, bucket_key.size) % bucket_size;
bucket_index %= bucket_size;
if(self->compare_func(value, bucket_node_get_value(bucket_node)) == 0)
return bool_true;
}
return bool_false;
}
#define MIN(a, b) ((a) < (b) ? (a) : (b))
int hash_compare_string(const void *a, const void *b) {
const BufferView *lhs;
const BufferView *rhs;
int mem_diff;
lhs = a;
rhs = b;
mem_diff = am_memcmp(lhs->data, rhs->data, MIN(lhs->size, rhs->size));
if(mem_diff == 0)
return (int)lhs->size - (int)rhs->size;
else
return mem_diff;
}
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