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#include "../include/hashmap.h"
#include "../include/alloc.h"
#include <string.h>
#include <assert.h>
/* Optimized div by sizeof(mgui_hashmap_entry*) */
#if INTPTR_MAX == INT64_MAX
#define CAP_NUM_ENTRIES(cap) ((cap) >> 3)
#elif INTPTR_MAX == INT32_MAX
#define CAP_NUM_ENTRIES(cap) ((cap) >> 2)
#else
#error Unsupported system. Only systems where a pointer is 32-bits or 64-bits are supported.
#endif
#define HASH_TO_INDEX(hash) (hash & (CAP_NUM_ENTRIES(self->capacity)-1))
#define HASHMAP_ENTRY_GET_KEY(entry) ((char*)(entry) + sizeof(mgui_hashmap_entry))
/* |align| should be a multiple of 2 */
static size_t align_to(size_t value, size_t align) {
const size_t is_aligned = (value & (align - 1));
if(is_aligned == 0) {
return value;
} else {
return (value & ~(align - 1)) + align;
}
}
void mgui_hashmap_init(mgui_hashmap *self) {
self->entries = NULL;
self->capacity = 0;
self->size = 0;
}
void mgui_hashmap_deinit(mgui_hashmap *self) {
if(self->entries) {
for(size_t i = 0; i < CAP_NUM_ENTRIES(self->capacity); ++i) {
mgui_hashmap_entry *entry = self->entries[i];
while(entry) {
mgui_hashmap_entry *next = entry->next;
mgui_free(entry);
entry = next;
}
}
mgui_free(self->entries);
self->entries = NULL;
}
self->capacity = 0;
self->size = 0;
}
static void mgui_hashmap_move_entry_to_front(mgui_hashmap *self, size_t index, mgui_hashmap_entry *new_entry) {
new_entry->next = self->entries[index];
self->entries[index] = new_entry;
}
static void mgui_hashmap_reorder_nodes(mgui_hashmap *self, size_t prev_capacity) {
for(size_t i = 0; i < CAP_NUM_ENTRIES(prev_capacity); ++i) {
mgui_hashmap_entry *entry = self->entries[i];
mgui_hashmap_entry *prev_entry = NULL;
while(entry) {
const uint64_t new_index = HASH_TO_INDEX(entry->hash);
mgui_hashmap_entry *next_entry = entry->next;
if(new_index != i) {
/* Remove entry by replacing this entry with the next entry */
if(prev_entry)
prev_entry->next = next_entry;
else
self->entries[i] = next_entry;
/* Insert the entry at the new index */
mgui_hashmap_move_entry_to_front(self, new_index, entry);
} else {
prev_entry = entry;
}
entry = next_entry;
}
}
}
static void mgui_hashmap_ensure_capacity(mgui_hashmap *self, size_t new_capacity) {
if(self->capacity > new_capacity)
return;
size_t cap = self->capacity;
if(cap == 0)
cap = 8;
while(cap < new_capacity) {
cap = cap + (cap >> 1); /* *= 1.5 */
}
size_t prev_capacity = self->capacity;
self->capacity = align_to(cap, sizeof(mgui_hashmap_entry*));
self->entries = mgui_realloc(self->entries, self->capacity);
memset((char*)self->entries + prev_capacity, 0, self->capacity - prev_capacity);
mgui_hashmap_reorder_nodes(self, prev_capacity);
}
void mgui_hashmap_insert(mgui_hashmap *self, const char *key, size_t key_size, void *value, uint64_t *hash_out) {
mgui_hashmap_ensure_capacity(self, (self->size + 1) * sizeof(mgui_hashmap_entry*));
++self->size;
const uint64_t hash = mgui_hashmap_hash(key, key_size);
const size_t index = HASH_TO_INDEX(hash);
#ifndef NDEBUG
void *value_out;
assert(!mgui_hashmap_get_by_hash(self, key, key_size, hash, &value_out));
#endif
if(hash_out)
*hash_out = hash;
mgui_hashmap_entry *new_entry = mgui_alloc(sizeof(mgui_hashmap_entry) + key_size);
new_entry->hash = hash;
new_entry->value = value;
new_entry->key_size = key_size;
memcpy(HASHMAP_ENTRY_GET_KEY(new_entry), key, key_size);
mgui_hashmap_move_entry_to_front(self, index, new_entry);
}
bool mgui_hashmap_get(mgui_hashmap *self, const char *key, size_t key_size, void **value_out) {
return mgui_hashmap_get_by_hash(self, key, key_size, mgui_hashmap_hash(key, key_size), value_out);
}
bool mgui_hashmap_get_by_hash(mgui_hashmap *self, const char *key, size_t key_size, uint64_t hash, void **value_out) {
assert(hash == mgui_hashmap_hash(key, key_size));
if(!self->entries)
return false;
const size_t index = HASH_TO_INDEX(hash);
mgui_hashmap_entry *entry = self->entries[index];
while(entry) {
if(hash == entry->hash && key_size == entry->key_size && memcmp(key, HASHMAP_ENTRY_GET_KEY(entry), key_size) == 0) {
*value_out = entry->value;
return true;
}
entry = entry->next;
}
return false;
}
/* TODO: Optimize by using xxHash instead */
/* fnv-1 hash */
uint64_t mgui_hashmap_hash(const char *data, size_t size) {
const unsigned char *unsigned_data = (const unsigned char*)data;
uint64_t hash = 14695981039346656037ULL;
for(size_t i = 0; i < size; ++i) {
hash *= 1099511628211ULL;
hash ^= unsigned_data[i];
}
return hash;
}
void mgui_hashmap_for_each(mgui_hashmap *self, bool(*callback)(void *value, void *userdata), void *userdata) {
if(!self->entries)
return;
for(size_t i = 0; i < CAP_NUM_ENTRIES(self->capacity); ++i) {
mgui_hashmap_entry *entry = self->entries[i];
while(entry) {
if(!callback(entry->value, userdata))
return;
entry = entry->next;
}
}
}
void mgui_hashmap_for_each_erase(mgui_hashmap *self, bool(*callback)(void *value, void *userdata), void *userdata) {
if(!self->entries)
return;
for(size_t i = 0; i < CAP_NUM_ENTRIES(self->capacity); ++i) {
mgui_hashmap_entry *entry = self->entries[i];
mgui_hashmap_entry *prev_entry = NULL;
while(entry) {
mgui_hashmap_entry *next = entry->next;
if(callback(entry->value, userdata)) {
/* Remove entry by replacing this entry with the next entry */
if(prev_entry)
prev_entry->next = next;
else
self->entries[i] = next;
mgui_free(entry);
} else {
prev_entry = entry;
}
entry = next;
}
}
}
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