source: mainline/uspace/app/sbi/src/intmap.c

/*
 * Copyright (c) 2010 Jiri Svoboda
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * - Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 * - Redistributions in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in the
 *   documentation and/or other materials provided with the distribution.
 * - The name of the author may not be used to endorse or promote products
 *   derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

/** @file Integer map.
 *
 * Maps integers to pointers (void *). Current implementation is trivial
 * (linked list of key-value pairs).
 */

#include <stdio.h>
#include <stdlib.h>
#include <assert.h>
#include "list.h"
#include "mytypes.h"

#include "intmap.h"

/** Initialize map.
 *
 * @param intmap        Map to initialize.
 */
void intmap_init(intmap_t *intmap)
{
        list_init(&intmap->elem);
}

/** Deinitialize map.
 *
 * The map must be already empty.
 *
 * @param intmap        Map to initialize.
 */
void intmap_fini(intmap_t *intmap)
{
        list_fini(&intmap->elem);
}

/** Set value corresponding to a key.
 *
 * If there already exists a mapping for @a key in the map, it is
 * silently replaced. If @a value is @c NULL, the mapping for @a key
 * is removed from the map.
 *
 * @param intmap        Map
 * @param key           Key (integer)
 * @param value         Value (must be a pointer) or @c NULL
 */
void intmap_set(intmap_t *intmap, int key, void *value)
{
        list_node_t *node;
        map_elem_t *elem;

        node = list_first(&intmap->elem);
        while (node != NULL) {
                elem = list_node_data(node, map_elem_t *);
                if (elem->key == key) {
                        if (value != NULL) {
                                /* Replace existing value. */
                                elem->value = value;
                        } else {
                                /* Remove map element. */
                                list_remove(&intmap->elem, node);
                                free(elem);
                        }
                        return;
                }
                node = list_next(&intmap->elem, node);
        }

        /* Allocate new map element and add it to the list. */

        elem = calloc(1, sizeof(map_elem_t));
        if (elem == NULL) {
                printf("Memory allocation failed.\n");
                exit(1);
        }

        elem->key = key;
        elem->value = value;
        list_append(&intmap->elem, elem);
}

/** Get value corresponding to a key.
 *
 * @param intmap        Map
 * @param key           Key for which to retrieve mapping
 *
 * @return              Value correspoding to @a key or @c NULL if no mapping
 *                      exists.
 */
void *intmap_get(intmap_t *intmap, int key)
{
        list_node_t *node;
        map_elem_t *elem;

        node = list_first(&intmap->elem);
        while (node != NULL) {
                elem = list_node_data(node, map_elem_t *);
                if (elem->key == key) {
                        return elem->value;
                }
                node = list_next(&intmap->elem, node);
        }

        /* Not found */
        return NULL;
}

/** Get first element in the map.
 *
 * For iterating over the map, this returns the first element (in no
 * particular order).
 *
 * @param intmap        Map
 * @return              Map element or NULL if the map is empty
 */
map_elem_t *intmap_first(intmap_t *intmap)
{
        list_node_t *node;

        node = list_first(&intmap->elem);
        if (node == NULL)
                return NULL;

        return list_node_data(node, map_elem_t *);
}

/** Get element key.
 *
 * Giver a map element, return the key.
 *
 * @param elem          Map element
 * @return              Key
 */
int intmap_elem_get_key(map_elem_t *elem)
{
        return elem->key;
}

/** Get element value.
 *
 * Giver a map element, return the value.
 *
 * @param elem          Map element
 * @return              Value
 */
void *intmap_elem_get_value(map_elem_t *elem)
{
        return elem->value;
}