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#include "hashmap.h"
#include <inttypes.h>
#include <string.h>
#include <stdlib.h>
#include <err.h>
#if SIZE_MAX == 0xFFFFFFFF
/* If size_t is 32bit */
static const size_t fnv_prime = 16777619u;
static const size_t fnv_offsetb = 2166136261u;
#elif SIZE_MAX == 0xFFFFFFFFFFFFFFFF
/* If size_t is 64bit */
static const size_t fnv_prime = 1099511628211u;
static const size_t fnv_offsetb = 14695981039346656037u;
#else
/* If size_t is 128bit. Maybe this is overdoing it? */
static const size_t fnv_prime = 309485009821345068724781371u;
static const size_t fnv_offsetb = 144066263297769815596495629667062367629u;
#endif
struct node {
const char *key;
void *value;
struct node *next;
};
/* FNV1a */
static size_t
hash(const char *str)
{
size_t hash = fnv_offsetb;
size_t i = 0;
while (str[i] != '\0') {
hash ^= str[i];
hash *= fnv_prime;
i++;
}
return hash;
}
static void
htable_realloc(struct hashmap *hm, struct node **oldbucks, size_t oldcap)
{
for (size_t i = 0; i < oldcap; i++) {
struct node *node = oldbucks[i];
while (node) {
size_t pos = hash(node->key) % hm->cur_cap;
if (hm->buckets[pos]) {
struct node *newnext = hm->buckets[pos],
*newprev;
do {
newprev = newnext;
newnext = newprev->next;
} while (newnext);
newprev->next = node;
} else {
hm->buckets[pos] = node;
}
struct node *prev = node;
node = prev->next;
prev->next = NULL;
}
}
free(oldbucks);
}
static bool
htable_grow(struct hashmap *hm)
{
float load = (float)hm->size / (float)hm->cur_cap;
if (load <= HASHMAP_MAX_LOAD) return true;
size_t oldcap = hm->cur_cap;
hm->cur_cap = hm->cur_cap * HASHMAP_GROW_RATE;
struct node **oldbucks = hm->buckets;
hm->buckets = calloc(hm->cur_cap, sizeof(**hm->buckets));
if (!hm->buckets) return false;
htable_realloc(hm, oldbucks, oldcap);
return true;
}
static bool
htable_shrink(struct hashmap *hm)
{
if (hm->cur_cap <= hm->init_cap) return true;
float load = (float)hm->size / (float)hm->cur_cap;
if (load >= HASHMAP_MIN_LOAD) return true;
size_t oldcap = hm->cur_cap;
hm->cur_cap = hm->cur_cap / HASHMAP_GROW_RATE;
struct node **oldbucks = hm->buckets;
hm->buckets = calloc(hm->cur_cap, sizeof(**hm->buckets));
if (!hm->buckets) return false;
htable_realloc(hm, oldbucks, oldcap);
return true;
}
struct hashmap *
hashmap_new_with_cap(size_t cap)
{
struct hashmap *hm = malloc(sizeof *hm);
hm->init_cap = cap;
hm->cur_cap = cap;
hm->size = 0;
if (hm == NULL) return NULL;
hm->buckets = calloc(cap, sizeof hm->buckets);
if (hm->buckets == NULL) {
free(hm);
return NULL;
}
return hm;
}
void *
hashmap_insert(struct hashmap *hm, const char *key, void *value)
{
int pos = hash(key) % hm->cur_cap;
struct node *head = hm->buckets[pos];
struct node *node = head;
void *old_value;
while (node) {
if (strcmp(node->key, key) == 0) {
old_value = node->value;
node->value = value;
return old_value;
}
node = node->next;
}
node = malloc(sizeof *node);
node->key = key;
node->value = value;
node->next = head;
hm->buckets[pos] = node;
hm->size++;
htable_grow(hm);
return NULL;
}
void *
hashmap_get(struct hashmap *hm, const char *key)
{
size_t pos = hash(key) % hm->cur_cap;
struct node *node = hm->buckets[pos];
while (node != NULL) {
if (strcmp(node->key, key) == 0) {
return node->value;
}
node = node->next;
}
return NULL;
}
void *
hashmap_resolve(struct hashmap *hm, const char *key)
{
char tmp_key[64];
int i = 0;
int j = 0;
while (1) {
for (j=0; key[i] != '.' && key[i] != '\0'; i++, j++) {
tmp_key[j] = key[i];
}
tmp_key[j] = '\0';
hm = hashmap_get(hm, tmp_key);
// stop if we read key to end of string
if (key[i] == '\0') {
break;
}
// otherwise, continue reading keys
i++;
}
return hm;
}
void *
hashmap_remove(struct hashmap *hm, const char *key)
{
int pos = hash(key) % hm->cur_cap;
struct node *node = hm->buckets[pos];
struct node *prev = NULL;
void *old_value;
while (node) {
if (strcmp(node->key, key) == 0) {
if (prev) {
prev->next = node->next;
} else {
hm->buckets[pos] = node->next;
}
old_value = node->value;
free(node);
hm->size--;
htable_shrink(hm);
return old_value;
}
prev = node;
node = node->next;
}
return NULL;
}
void
hashmap_walk(struct hashmap *hm, void (*fn)(const void *key, void *value))
{
struct node *node;
struct node *next;
for (int i=0; i < hm->cur_cap; i++) {
node = hm->buckets[i];
while (node) {
next = node->next;
fn(node->key, node->value);
node = next;
}
}
}
void
hashmap_free(struct hashmap *hm)
{
struct node *node;
struct node *next;
for (int i=0; i < hm->cur_cap; i++) {
node = hm->buckets[i];
while (node) {
next = node->next;
free(node);
node = next;
}
}
free(hm->buckets);
free(hm);
}
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