breakhack/src/hashtable.c

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2018-02-16 18:11:26 +01:00
/*
* BreakHack - A dungeone crawler RPG
* Copyright (C) 2018 Linus Probert <linus.probert@gmail.com>
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <limits.h>
#include "hashtable.h"
#include "defines.h"
#include "util.h"
Hashtable*
ht_create(unsigned int size)
{
Hashtable *table;
unsigned int i;
if (size < 1)
return NULL;
table = ec_malloc(sizeof(Hashtable));
table->size = size;
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table->entries = ec_malloc((unsigned int) sizeof(Entry) * size);
for (i = 0; i < size; ++i) {
table->entries[i] = NULL;
}
return table;
}
/* D. J. Bernstein hash function */
static unsigned int
hash(Hashtable *table, const char *key)
{
unsigned int hash = 5381;
while (*key) {
hash = 33 * hash ^ (unsigned char) *key++;
}
return hash % 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)
{
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unsigned int hashkey = 0;
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Entry *newEntry = NULL;
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Entry *next;
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Entry *last = NULL;
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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;
}
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if (last == NULL)
last = table->entries[hashkey];
if (next && next->key && strcmp(key, next->key) == 0) {
/* Collision */
free(next->value);
next->value = val;
} else {
/* New entry */
newEntry = entry_create(key, val);
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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)
{
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unsigned 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_remove(Hashtable *table, const char *key)
{
unsigned int hashkey = 0;
Entry *entry, *last;
hashkey = hash(table, key);
entry = table->entries[hashkey];
last = NULL;
while (entry && entry->key && strcmp(entry->key, key) < 0) {
last = entry;
entry = entry->next;
}
if (!entry || !entry->key || strcmp(entry->key, key) != 0) {
return NULL;
}
if (last == NULL) {
table->entries[hashkey] = entry->next;
} else {
last->next = entry->next;
}
void *value = entry->value;
free(entry->key);
free(entry);
return value;
}
void
ht_destroy(Hashtable *table)
{
ht_destroy_custom(table, free);
}
void
ht_foreach(Hashtable *table, void (*func)(void*))
{
Entry *entry;
unsigned int i;
if (table == NULL) {
return;
}
for (i = 0; i < table->size; ++i) {
entry = table->entries[i];
if (entry == NULL)
continue;
while (entry) {
func(entry->value);
entry = entry->next;
}
}
}
void
ht_destroy_custom(Hashtable *table, void (*destroy_value)(void *))
{
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);
}