Hashtable resizing leaks memory
- by thpetrus
I wrote a hashtable and it basically consists of these two structures:
typedef struct dictEntry {
void *key;
void *value;
struct dictEntry *next;
} dictEntry;
typedef struct dict {
dictEntry **table;
unsigned long size;
unsigned long items;
} dict;
dict.table is a multidimensional array, which contains all the stored key/value pair, which again are a linked list.
If half of the hashtable is full, I expand it by doubling the size and rehashing it:
dict *_dictRehash(dict *d) {
int i;
dict *_d;
dictEntry *dit;
_d = dictCreate(d->size * 2);
for (i = 0; i < d->size; i++) {
for (dit = d->table[i]; dit != NULL; dit = dit->next) {
_dictAddRaw(_d, dit);
}
}
/* FIXME memory leak because the old dict can never be freed */
free(d); // seg fault
return _d;
}
The function above uses the pointers from the old hash table and stores it in the newly created one. When freeing the old dict d a Segmentation Fault occurs.
How am I able to free the old hashtable struct without having to allocate the memory for the key/value pairs again?
