WebSVN – HelenOS – Diff – /trunk/uspace/lib/libc/generic/libadt/hash_table.c


/*
 * Copyright (c) 2008 Jakub Jermar
 * 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.
 */
 
/** @addtogroup libc
 * @{
 */
/** @file
 */
 
/*
 * This is an implementation of generic chained hash table.
 */
 
#include <libadt/hash_table.h>
#include <libadt/list.h>
#include <unistd.h>
#include <malloc.h>
#include <assert.h>
#include <stdio.h>
#include <string.h>
 
/** Create chained hash table.
 *
 * @param h     Hash table structure. Will be initialized by this call.
 * @param m     Number of hash table buckets.
 * @param max_keys  Maximal number of keys needed to identify an item.
 * @param op        Hash table operations structure.
 * @return      True on success
 */
int hash_table_create(hash_table_t *h, hash_count_t m, hash_count_t max_keys,
    hash_table_operations_t *op)
{
    hash_count_t i;
 
    assert(h);
    assert(op && op->hash && op->compare);
    assert(max_keys > 0);
   
    h->entry = malloc(m * sizeof(link_t));
    if (!h->entry) {
        printf("cannot allocate memory for hash table\n");
        return false;
    }
    memset((void *) h->entry, 0,  m * sizeof(link_t));
   
    for (i = 0; i < m; i++)
        list_initialize(&h->entry[i]);
   
    h->entries = m;
    h->max_keys = max_keys;
    h->op = op;
    return true;
}
 
/** Destroy a hash table instance.
 *
 * @param h     Hash table to be destroyed.
 */
void hash_table_destroy(hash_table_t *h)
{
    assert(h);
    assert(h->entry);
    free(h->entry);
}
 
/** Insert item into a hash table.
 *
 * @param h     Hash table.
 * @param key       Array of all keys necessary to compute hash index.
 * @param item      Item to be inserted into the hash table.
 */
void hash_table_insert(hash_table_t *h, unsigned long key[], link_t *item)
{
    hash_index_t chain;
 
    assert(item);
    assert(h && h->op && h->op->hash && h->op->compare);
 
    chain = h->op->hash(key);
    assert(chain < h->entries);
   
    list_append(item, &h->entry[chain]);
}
 
/** Search hash table for an item matching keys.
 *
 * @param h     Hash table.
 * @param key       Array of all keys needed to compute hash index.
 *
 * @return      Matching item on success, NULL if there is no such item.
 */
link_t *hash_table_find(hash_table_t *h, unsigned long key[])
{
    link_t *cur;
    hash_index_t chain;
 
    assert(h && h->op && h->op->hash && h->op->compare);
 
    chain = h->op->hash(key);
    assert(chain < h->entries);
   
    for (cur = h->entry[chain].next; cur != &h->entry[chain];
        cur = cur->next) {
        if (h->op->compare(key, h->max_keys, cur)) {
            /*
             * The entry is there.
             */
            return cur;
        }
    }
   
    return NULL;
}
 
/** Remove all matching items from hash table.
 *
 * For each removed item, h->remove_callback() is called.
 *
 * @param h     Hash table.
 * @param key       Array of keys that will be compared against items of
 *          the hash table.
 * @param keys      Number of keys in the 'key' array.
 */
void hash_table_remove(hash_table_t *h, unsigned long key[], hash_count_t keys)
{
    hash_index_t chain;
    link_t *cur;
 
    assert(h && h->op && h->op->hash && h->op->compare &&
        h->op->remove_callback);
    assert(keys <= h->max_keys);
   
    if (keys == h->max_keys) {
 
        /*
         * All keys are known, hash_table_find() can be used to find the
         * entry.
         */
   
        cur = hash_table_find(h, key);
        if (cur) {
            list_remove(cur);
            h->op->remove_callback(cur);
        }
        return;
    }
   
    /*
     * Fewer keys were passed.
     * Any partially matching entries are to be removed.
     */
    for (chain = 0; chain < h->entries; chain++) {
        for (cur = h->entry[chain].next; cur != &h->entry[chain];
            cur = cur->next) {
            if (h->op->compare(key, keys, cur)) {
                link_t *hlp;
               
                hlp = cur;
                cur = cur->prev;
               
                list_remove(hlp);
                h->op->remove_callback(hlp);
               
                continue;
            }
        }
    }
}
 
/** @}
 */
 

Rev 2479	Rev 2759
1	/*	1	/*
2	* Copyright (c) 2006 Jakub Jermar	2	* Copyright (c) 2008 Jakub Jermar
3	* All rights reserved.	3	* All rights reserved.
4	*	4	*
5	* Redistribution and use in source and binary forms, with or without	5	* Redistribution and use in source and binary forms, with or without
6	* modification, are permitted provided that the following conditions	6	* modification, are permitted provided that the following conditions
7	* are met:	7	* are met:
8	*	8	*
9	* - Redistributions of source code must retain the above copyright	9	* - Redistributions of source code must retain the above copyright
10	* notice, this list of conditions and the following disclaimer.	10	* notice, this list of conditions and the following disclaimer.
11	* - Redistributions in binary form must reproduce the above copyright	11	* - Redistributions in binary form must reproduce the above copyright
12	* notice, this list of conditions and the following disclaimer in the	12	* notice, this list of conditions and the following disclaimer in the
13	* documentation and/or other materials provided with the distribution.	13	* documentation and/or other materials provided with the distribution.
14	* - The name of the author may not be used to endorse or promote products	14	* - The name of the author may not be used to endorse or promote products
15	* derived from this software without specific prior written permission.	15	* derived from this software without specific prior written permission.
16	*	16	*
17	* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR	17	* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
18	* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES	18	* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19	* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.	19	* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20	* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,	20	* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21	* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT	21	* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22	* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,	22	* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23	* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY	23	* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24	* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT	24	* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25	* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF	25	* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26	* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.	26	* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27	*/	27	*/
28		28
29	/** @addtogroup libc	29	/** @addtogroup libc
30	* @{	30	* @{
31	*/	31	*/
32	/** @file	32	/** @file
33	*/	33	*/
34		34
35	/*	35	/*
36	* This is an implementation of generic chained hash table.	36	* This is an implementation of generic chained hash table.
37	*/	37	*/
38		38
39	#include <libadt/hash_table.h>	39	#include <libadt/hash_table.h>
40	#include <libadt/list.h>	40	#include <libadt/list.h>
41	#include <unistd.h>	41	#include <unistd.h>
42	#include <malloc.h>	42	#include <malloc.h>
43	#include <assert.h>	43	#include <assert.h>
44	#include <stdio.h>	44	#include <stdio.h>
45	#include <string.h>	45	#include <string.h>
46		46
47	/** Create chained hash table.	47	/** Create chained hash table.
48	*	48	*
49	* @param h Hash table structure. Will be initialized by this call.	49	* @param h Hash table structure. Will be initialized by this call.
50	* @param m Number of slots in the hash table.	50	* @param m Number of hash table buckets.
51	* @param max_keys Maximal number of keys needed to identify an item.	51	* @param max_keys Maximal number of keys needed to identify an item.
52	* @param op Hash table operations structure.	52	* @param op Hash table operations structure.
53	* @return true on success	53	* @return True on success
54	*/	54	*/
55	int hash_table_create(hash_table_t h, hash_count_t m, hash_count_t max_keys, hash_table_operations_t op)	55	int hash_table_create(hash_table_t *h, hash_count_t m, hash_count_t max_keys,
-		56	hash_table_operations_t *op)
56	{	57	{
57	hash_count_t i;	58	hash_count_t i;
58		59
59	assert(h);	60	assert(h);
60	assert(op && op->hash && op->compare);	61	assert(op && op->hash && op->compare);
61	assert(max_keys > 0);	62	assert(max_keys > 0);
62		63
63	h->entry = malloc(m * sizeof(link_t));	64	h->entry = malloc(m * sizeof(link_t));
64	if (!h->entry) {	65	if (!h->entry) {
65	printf("cannot allocate memory for hash table\n");	66	printf("cannot allocate memory for hash table\n");
66	return false;	67	return false;
67	}	68	}
68	memset((void ) h->entry, 0, m sizeof(link_t));	69	memset((void ) h->entry, 0, m sizeof(link_t));
69		70
70	for (i = 0; i < m; i++)	71	for (i = 0; i < m; i++)
71	list_initialize(&h->entry[i]);	72	list_initialize(&h->entry[i]);
72		73
73	h->entries = m;	74	h->entries = m;
74	h->max_keys = max_keys;	75	h->max_keys = max_keys;
75	h->op = op;	76	h->op = op;
76	return true;	77	return true;
77	}	78	}
78		79
79	/** Insert item into hash table.	80	/** Destroy a hash table instance.
80	*	81	*
-		82	* @param h Hash table to be destroyed.
-		83	*/
-		84	void hash_table_destroy(hash_table_t *h)
-		85	{
-		86	assert(h);
-		87	assert(h->entry);
-		88	free(h->entry);
-		89	}
-		90
-		91	/** Insert item into a hash table.
-		92	*
81	* @param h Hash table.	93	* @param h Hash table.
82	* @param key Array of all keys necessary to compute hash index.	94	* @param key Array of all keys necessary to compute hash index.
83	* @param item Item to be inserted into the hash table.	95	* @param item Item to be inserted into the hash table.
84	*/	96	*/
85	void hash_table_insert(hash_table_t h, unsigned long key[], link_t item)	97	void hash_table_insert(hash_table_t h, unsigned long key[], link_t item)
86	{	98	{
87	hash_index_t chain;	99	hash_index_t chain;
88		100
89	assert(item);	101	assert(item);
90	assert(h && h->op && h->op->hash && h->op->compare);	102	assert(h && h->op && h->op->hash && h->op->compare);
91		103
92	chain = h->op->hash(key);	104	chain = h->op->hash(key);
93	assert(chain < h->entries);	105	assert(chain < h->entries);
94		106
95	list_append(item, &h->entry[chain]);	107	list_append(item, &h->entry[chain]);
96	}	108	}
97		109
98	/** Search hash table for an item matching keys.	110	/** Search hash table for an item matching keys.
99	*	111	*
100	* @param h Hash table.	112	* @param h Hash table.
101	* @param key Array of all keys needed to compute hash index.	113	* @param key Array of all keys needed to compute hash index.
102	*	114	*
103	* @return Matching item on success, NULL if there is no such item.	115	* @return Matching item on success, NULL if there is no such item.
104	*/	116	*/
105	link_t hash_table_find(hash_table_t h, unsigned long key[])	117	link_t hash_table_find(hash_table_t h, unsigned long key[])
106	{	118	{
107	link_t *cur;	119	link_t *cur;
108	hash_index_t chain;	120	hash_index_t chain;
109		121
110	assert(h && h->op && h->op->hash && h->op->compare);	122	assert(h && h->op && h->op->hash && h->op->compare);
111		123
112	chain = h->op->hash(key);	124	chain = h->op->hash(key);
113	assert(chain < h->entries);	125	assert(chain < h->entries);
114		126
115	for (cur = h->entry[chain].next; cur != &h->entry[chain]; cur = cur->next) {	127	for (cur = h->entry[chain].next; cur != &h->entry[chain];
-		128	cur = cur->next) {
116	if (h->op->compare(key, h->max_keys, cur)) {	129	if (h->op->compare(key, h->max_keys, cur)) {
117	/*	130	/*
118	* The entry is there.	131	* The entry is there.
119	*/	132	*/
120	return cur;	133	return cur;
121	}	134	}
122	}	135	}
123		136
124	return NULL;	137	return NULL;
125	}	138	}
126		139
127	/** Remove all matching items from hash table.	140	/** Remove all matching items from hash table.
128	*	141	*
129	* For each removed item, h->remove_callback() is called.	142	* For each removed item, h->remove_callback() is called.
130	*	143	*
131	* @param h Hash table.	144	* @param h Hash table.
132	* @param key Array of keys that will be compared against items of the hash table.	145	* @param key Array of keys that will be compared against items of
-		146	* the hash table.
133	* @param keys Number of keys in the 'key' array.	147	* @param keys Number of keys in the 'key' array.
134	*/	148	*/
135	void hash_table_remove(hash_table_t *h, unsigned long key[], hash_count_t keys)	149	void hash_table_remove(hash_table_t *h, unsigned long key[], hash_count_t keys)
136	{	150	{
137	hash_index_t chain;	151	hash_index_t chain;
138	link_t *cur;	152	link_t *cur;
139		153
140	assert(h && h->op && h->op->hash && h->op->compare && h->op->remove_callback);	154	assert(h && h->op && h->op->hash && h->op->compare &&
-		155	h->op->remove_callback);
141	assert(keys <= h->max_keys);	156	assert(keys <= h->max_keys);
142		157
143	if (keys == h->max_keys) {	158	if (keys == h->max_keys) {
144		159
145	/*	160	/*
146	* All keys are known, hash_table_find() can be used to find the entry.	161	* All keys are known, hash_table_find() can be used to find the
-		162	* entry.
147	*/	163	*/
148		164
149	cur = hash_table_find(h, key);	165	cur = hash_table_find(h, key);
150	if (cur) {	166	if (cur) {
151	list_remove(cur);	167	list_remove(cur);
152	h->op->remove_callback(cur);	168	h->op->remove_callback(cur);
153	}	169	}
154	return;	170	return;
155	}	171	}
156		172
157	/*	173	/*
158	* Fewer keys were passed.	174	* Fewer keys were passed.
159	* Any partially matching entries are to be removed.	175	* Any partially matching entries are to be removed.
160	*/	176	*/
161	for (chain = 0; chain < h->entries; chain++) {	177	for (chain = 0; chain < h->entries; chain++) {
162	for (cur = h->entry[chain].next; cur != &h->entry[chain]; cur = cur->next) {	178	for (cur = h->entry[chain].next; cur != &h->entry[chain];
-		179	cur = cur->next) {
163	if (h->op->compare(key, keys, cur)) {	180	if (h->op->compare(key, keys, cur)) {
164	link_t *hlp;	181	link_t *hlp;
165		182
166	hlp = cur;	183	hlp = cur;
167	cur = cur->prev;	184	cur = cur->prev;
168		185
169	list_remove(hlp);	186	list_remove(hlp);
170	h->op->remove_callback(hlp);	187	h->op->remove_callback(hlp);
171		188
172	continue;	189	continue;
173	}	190	}
174	}	191	}
175	}	192	}
176	}	193	}
177		194
178	/** @}	195	/** @}
179	*/	196	*/
180		197

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(root)/trunk/uspace/lib/libc/generic/libadt/hash_table.c – Rev 2479 → 2759