breakhack/hashtable/hashtable.c

160 lines
2.6 KiB
C

#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <limits.h>
#include "hashtable.h"
static void*
ec_malloc(unsigned int size)
{
void *ptr = malloc(size);
if (ptr == NULL) {
fprintf(stderr, "[!!] Failed to allocate hashtable\n");
exit(-1);
}
return ptr;
}
Hashtable*
ht_create(unsigned int size)
{
Hashtable *table;
unsigned int i;
if (size < 1)
return NULL;
table = ec_malloc(sizeof(Hashtable));
table->size = size;
table->entries = ec_malloc(sizeof(Entry) * size);
for (i = 0; i < size; ++i) {
table->entries[i] = NULL;
}
return table;
}
static unsigned int
hash(Hashtable *table, const char *key)
{
unsigned long int hashval = 0;
int i = 0;
while (hashval < ULONG_MAX && i < strlen(key)) {
hashval = hashval << 8;
hashval += key[i++];
}
return hashval % table->size;
}
static Entry*
entry_create(const char *key, void *value)
{
Entry *entry;
entry = ec_malloc(sizeof(Entry));
entry->key = strdup(key);
entry->value = value;
entry->next = NULL;
return entry;
}
void
ht_set(Hashtable *table, const char *key, void *val)
{
int hashkey = 0;
Entry *newEntry;
Entry *next;
Entry *last;
hashkey = hash(table, key);
next = table->entries[hashkey];
/* Find a position */
while (next != NULL
&& next->key != NULL
&& strcmp(key, next->key) > 0)
{
last = next;
next = next->next;
}
if (next && next->key && strcmp(key, next->key) == 0) {
/* Collision */
free(next->value);
next->value = val;
} else {
/* New entry */
newEntry = entry_create(key, val);
if (next == table->entries[hashkey]) {
table->entries[hashkey] = newEntry;
newEntry->next = next;
} else if(next == NULL) {
last->next = newEntry;
} else {
newEntry->next = next;
last->next = newEntry;
}
}
}
void*
ht_get(Hashtable *table, const char *key)
{
int hashkey = 0;
Entry *entry;
hashkey = hash(table, key);
entry = table->entries[hashkey];
while (entry && entry->key && strcmp(entry->key, key) > 0) {
entry = entry->next;
}
if (!entry || !entry->key || strcmp(entry->key, key) != 0) {
return NULL;
}
return entry->value;
}
void
ht_destroy(Hashtable *table)
{
ht_destroy_custom(table, free);
}
void
ht_destroy_custom(Hashtable *table, void (*destroy_value)(void *value))
{
Entry *entry, *next;
unsigned int i;
if (table == NULL) {
return;
}
for (i = 0; i < table->size; ++i) {
entry = table->entries[i];
if (entry == NULL)
continue;
while (entry) {
next = entry->next;
destroy_value(entry->value);
entry->value = NULL;
free(entry->key);
free(entry);
entry = next;
}
}
free(table->entries);
free(table);
}