Added basic implementation of hash table.
This commit is contained in:
Glenn Y. Rolland
parent
fa8bbd7001
commit
70022ae1f6
1 changed files with 144 additions and 0 deletions
144
src/hashtable-simple.c
Normal file
144
src/hashtable-simple.c
Normal file
|
|
@ -0,0 +1,144 @@
|
||||||
|
#include <stdio.h>
|
||||||
|
#include <stdlib.h>
|
||||||
|
#include <string.h>
|
||||||
|
|
||||||
|
typedef struct hashcell_t {
|
||||||
|
char key[128];
|
||||||
|
void * value;
|
||||||
|
struct hashcell_t* next;
|
||||||
|
} HASHCELL;
|
||||||
|
|
||||||
|
typedef struct {
|
||||||
|
int capacity;
|
||||||
|
int size;
|
||||||
|
HASHCELL** data;
|
||||||
|
} HASHTABLE;
|
||||||
|
|
||||||
|
int hash_of_key(HASHTABLE* hashtable, char * key) {
|
||||||
|
return 0;
|
||||||
|
}
|
||||||
|
|
||||||
|
HASHTABLE* hashtable_create(int capacity) {
|
||||||
|
HASHTABLE * hashtable;
|
||||||
|
printf("hashtable_create -- %d\n", capacity);
|
||||||
|
|
||||||
|
hashtable = malloc(sizeof(HASHTABLE));
|
||||||
|
if (!hashtable) return NULL;
|
||||||
|
memset(hashtable, 0, sizeof(HASHTABLE));
|
||||||
|
|
||||||
|
hashtable->data = malloc(capacity * sizeof(HASHCELL*));
|
||||||
|
if (!hashtable->data) return NULL;
|
||||||
|
memset(hashtable->data, 0, capacity * sizeof(HASHCELL*));
|
||||||
|
|
||||||
|
hashtable->capacity = capacity;
|
||||||
|
hashtable->size = 0;
|
||||||
|
|
||||||
|
printf("hashtable_create -- done\n");
|
||||||
|
return hashtable;
|
||||||
|
}
|
||||||
|
|
||||||
|
void hashtable_destroy(HASHTABLE* hashtable) {
|
||||||
|
printf("hashtable_destroy(%p) -- \n", (void*)hashtable);
|
||||||
|
if (!hashtable) return;
|
||||||
|
if (!hashtable->data) return;
|
||||||
|
free(hashtable->data);
|
||||||
|
free(hashtable);
|
||||||
|
printf("hashtable_destroy(%p) -- done\n", (void*)hashtable);
|
||||||
|
}
|
||||||
|
|
||||||
|
void hashtable_rehash(HASHTABLE* hashtable) {
|
||||||
|
return;
|
||||||
|
}
|
||||||
|
|
||||||
|
int hashtable_set(HASHTABLE* hashtable, char* key, void * value) {
|
||||||
|
int idx;
|
||||||
|
HASHCELL* cell;
|
||||||
|
|
||||||
|
printf("hashtable_set(%s, %p) -- \n", key, (void*)value);
|
||||||
|
// get position in hashtable
|
||||||
|
idx = hash_of_key(hashtable, key);
|
||||||
|
hashtable->size += 1;
|
||||||
|
|
||||||
|
printf("hashtable_set -- search value [%d/%d]\n", idx, hashtable->capacity);
|
||||||
|
// search value
|
||||||
|
cell = hashtable->data[idx];
|
||||||
|
while(cell) {
|
||||||
|
if (strcmp(cell->key, key) == 0) { break; }
|
||||||
|
cell = cell->next;
|
||||||
|
}
|
||||||
|
|
||||||
|
if (cell) {
|
||||||
|
// if cell exists, then change inner value
|
||||||
|
printf("hashtable_set -- update value\n");
|
||||||
|
} else {
|
||||||
|
printf("hashtable_set -- create value\n");
|
||||||
|
// create cell & prepend it to the chain
|
||||||
|
cell = malloc(sizeof(HASHCELL));
|
||||||
|
if (!cell) return -1;
|
||||||
|
memset(cell, 0, sizeof(HASHCELL));
|
||||||
|
|
||||||
|
cell->next = hashtable->data[idx];
|
||||||
|
cell->value = value;
|
||||||
|
strcpy(cell->key, key);
|
||||||
|
hashtable->data[idx] = cell;
|
||||||
|
printf("hashtable_set -- cell@%p{key=%s, value=%p, next=%p}\n",
|
||||||
|
(void*)cell,
|
||||||
|
cell->key,
|
||||||
|
(void*)cell->value,
|
||||||
|
(void*)cell->next);
|
||||||
|
}
|
||||||
|
printf("hashtable_set -- done\n");
|
||||||
|
|
||||||
|
return 0;
|
||||||
|
}
|
||||||
|
|
||||||
|
void * hashtable_get(HASHTABLE* hashtable, char* key) {
|
||||||
|
int idx;
|
||||||
|
HASHCELL* cell;
|
||||||
|
printf("hashtable_get(%p, %p) -- \n", hashtable, key);
|
||||||
|
idx = hash_of_key(hashtable, key);
|
||||||
|
cell = hashtable->data[idx];
|
||||||
|
while(cell) {
|
||||||
|
printf("hashtable_get(...) -- cell@%p{key=%s, value=%p, next=%p}\n",
|
||||||
|
(void*)cell,
|
||||||
|
cell->key,
|
||||||
|
cell->value,
|
||||||
|
cell->next);
|
||||||
|
if (strcmp(cell->key, key) == 0) { break; }
|
||||||
|
cell = cell->next;
|
||||||
|
}
|
||||||
|
if (cell) {
|
||||||
|
return cell->value;
|
||||||
|
} else {
|
||||||
|
printf("hashtable_get(...) -- cell not found\n");
|
||||||
|
return NULL;
|
||||||
|
}
|
||||||
|
}
|
||||||
|
|
||||||
|
int main(int argc, char** argv) {
|
||||||
|
HASHTABLE * hashtable;
|
||||||
|
int x=1, y=2, z=3;
|
||||||
|
int* value;
|
||||||
|
|
||||||
|
printf("Run !\n");
|
||||||
|
hashtable = hashtable_create(1000);
|
||||||
|
hashtable_destroy(hashtable);
|
||||||
|
|
||||||
|
hashtable = hashtable_create(100);
|
||||||
|
hashtable_set(hashtable, "alice", &x);
|
||||||
|
printf("h['alice'] <- %d\n", x);
|
||||||
|
hashtable_set(hashtable, "bob", &y);
|
||||||
|
printf("h['bob'] <- %d\n", x);
|
||||||
|
hashtable_set(hashtable, "charlie", &z);
|
||||||
|
printf("h['charlie'] <- %d\n", x);
|
||||||
|
hashtable_set(hashtable, "alice", &y);
|
||||||
|
value = hashtable_get(hashtable, "alice");
|
||||||
|
printf("h['alice'] ? %d\n", *value);
|
||||||
|
value = hashtable_get(hashtable, "bob");
|
||||||
|
printf("h['bob'] ? %d\n", *value);
|
||||||
|
value = hashtable_get(hashtable, "charlie");
|
||||||
|
printf("h['charlie'] ? %d\n", *value);
|
||||||
|
|
||||||
|
return EXIT_SUCCESS;
|
||||||
|
}
|
||||||
|
|
||||||
Loading…
Reference in a new issue