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/*
* khm - (Linux) kernel hash map implementation
*
* Copyright (c) 2011 Guillermo Ramos <0xwille@gmail.com>
*
* This file is part of khm
*
* khm 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.
*
* khm 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 khm. If not, see <http://www.gnu.org/licenses/>.
*/
#include <linux/errno.h>
#include <linux/list.h>
#include <linux/slab.h>
#include "khm.h"
/*
* Returns the node with the value passed, or NULL in case it does not exist
*/
static inline struct khashmap *khm_search(struct khashmap *head, int value)
{
struct list_head *list;
struct khashmap *node;
list_for_each(list, &head->l) {
node = list_entry(list, struct khashmap, l);
if (node->value == value)
return node;
}
return NULL;
}
/*
* Prints in klog a representation of all the nodes in the hashmap
*/
void khm_display(struct khashmap *head)
{
struct khashmap *node;
struct list_head *list;
printk(KERN_ALERT "Displaying...");
list_for_each(list, &head->l) {
node = list_entry(list, struct khashmap, l);
printk(KERN_ALERT " %p: v=%d d=%s\n",
node, node->value, (char*)node->data);
}
}
/*
* Creates and returns a new head node
*/
inline struct khashmap *khm_create(void)
{
struct khashmap *head;
head = kmalloc(sizeof(struct khashmap), GFP_KERNEL);
if (!head)
return NULL;
INIT_LIST_HEAD(&head->l);
return head;
}
/*
* Deletes the hashmap and frees the memory used by its nodes
*/
void khm_destroy(struct khashmap *head)
{
struct khashmap *node;
struct list_head *list = head->l.next;
while (list != &head->l) {
node = list_entry(list, struct khashmap, l);
list = list->next;
kfree(node);
}
kfree(head);
}
/*
* Creates a new node with the given value and data, and adds it to the hm head
*/
int khm_insert(struct khashmap *head, int value, void *data)
{
struct khashmap *new;
// Key already exists
if (khm_search(head, value))
return -EINVAL;
new = khm_create();
if (!new)
return -ENOMEM;
new->value = value;
new->data = data;
list_add_tail(&new->l, &head->l);
return 0;
}
/*
* Removes from the hashmap the node with the given value.
*/
int khm_delete(struct khashmap *head, int value)
{
struct khashmap *node = khm_search(head, value);
if (node) {
list_del(&node->l);
kfree(node);
return 0;
} else {
return -EINVAL;
}
}
/*
* Returns the data mapped to the given value, or NULL if that value has no data
* associated to it
*/
void *khm_get(struct khashmap *head, int value)
{
struct khashmap *node = khm_search(head, value);
if (node)
return node->data;
else
return NULL;
}
/*
* Associates the given value with new data, if the value was already in the hm
*/
void khm_set(struct khashmap *head, int value, void *data)
{
struct khashmap *node = khm_search(head, value);
if (node)
node->data = data;
}
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