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#include <string.h>
#include <stdlib.h>
#include <err.h>
#include "hashmap.h"
struct node {
char *key;
void *value;
struct node *next;
};
unsigned long
hash(char *str)
{
unsigned long hash = 5381;
int c;
while ((c = *str++)) {
hash = ((hash << 5) + hash) + c; /* hash * 33 + c */
}
return hash;
}
/* allocate a new hashmap */
struct hashmap *hashmap_new() {
struct hashmap *hm = malloc(sizeof *hm);
if (!hm) err(EXIT_FAILURE, "out of memory");
for (int i=0; i < HASHMAP_CAP; i++) {
hm->buckets[i] = NULL;
}
return hm;
}
/* Inserts a key-value pair into the map. Returns NULL if map did not have key, old value if it did. */
void *hashmap_insert(struct hashmap *hm, char *key, void *value) {
int pos = hash(key) % HASHMAP_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;
return NULL;
}
/* Returns a pointer to the value corresponding to the key. */
void *hashmap_get(struct hashmap *hm, char *key) {
unsigned int pos = hash(key) % HASHMAP_CAP;
struct node *node = hm->buckets[pos];
while (node != NULL) {
if (strcmp(node->key, key) == 0) {
return node->value;
}
node = node->next;
}
return NULL;
}
/* Retrieve pointer to value by key, handles dot notation for nested hashmaps */
void *hashmap_resolve(struct hashmap *hm, 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;
}
/* Removes a key from the map, returning the value at the key if the key was previously in the map. */
void *hashmap_remove(struct hashmap *hm, char *key) {
int pos = hash(key) % HASHMAP_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);
return old_value;
}
node = node->next;
prev = node;
}
return NULL;
}
void hashmap_walk(struct hashmap *hm, void (*fn)(void *value)) {
struct node *node;
struct node *next;
for (int i=0; i < HASHMAP_CAP; i++) {
node = hm->buckets[i];
while (node) {
next = node->next;
fn(node->value);
node = next;
}
}
}
/* free hashmap related memory */
void hashmap_free(struct hashmap *hm) {
struct node *node;
struct node *next;
for (int i=0; i < HASHMAP_CAP; i++) {
node = hm->buckets[i];
while (node) {
next = node->next;
free(node);
node = next;
}
}
free(hm);
}
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