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/*
* Copyright (C) 2001-2004 Sistina Software, Inc. All rights reserved.
* Copyright (C) 2004-2011 Red Hat, Inc. All rights reserved.
*
* This file is part of the device-mapper userspace tools.
*
* This copyrighted material is made available to anyone wishing to use,
* modify, copy, or redistribute it subject to the terms and conditions
* of the GNU Lesser General Public License v.2.1.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this program; if not, write to the Free Software Foundation,
* Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include "dmlib.h"
struct dm_hash_node {
struct dm_hash_node *next;
void *data;
unsigned keylen;
char key[0];
};
struct dm_hash_table {
unsigned num_nodes;
unsigned num_slots;
struct dm_hash_node **slots;
};
/* Permutation of the Integers 0 through 255 */
static unsigned char _nums[] = {
1, 14, 110, 25, 97, 174, 132, 119, 138, 170, 125, 118, 27, 233, 140, 51,
87, 197, 177, 107, 234, 169, 56, 68, 30, 7, 173, 73, 188, 40, 36, 65,
49, 213, 104, 190, 57, 211, 148, 223, 48, 115, 15, 2, 67, 186, 210, 28,
12, 181, 103, 70, 22, 58, 75, 78, 183, 167, 238, 157, 124, 147, 172,
144,
176, 161, 141, 86, 60, 66, 128, 83, 156, 241, 79, 46, 168, 198, 41, 254,
178, 85, 253, 237, 250, 154, 133, 88, 35, 206, 95, 116, 252, 192, 54,
221,
102, 218, 255, 240, 82, 106, 158, 201, 61, 3, 89, 9, 42, 155, 159, 93,
166, 80, 50, 34, 175, 195, 100, 99, 26, 150, 16, 145, 4, 33, 8, 189,
121, 64, 77, 72, 208, 245, 130, 122, 143, 55, 105, 134, 29, 164, 185,
194,
193, 239, 101, 242, 5, 171, 126, 11, 74, 59, 137, 228, 108, 191, 232,
139,
6, 24, 81, 20, 127, 17, 91, 92, 251, 151, 225, 207, 21, 98, 113, 112,
84, 226, 18, 214, 199, 187, 13, 32, 94, 220, 224, 212, 247, 204, 196,
43,
249, 236, 45, 244, 111, 182, 153, 136, 129, 90, 217, 202, 19, 165, 231,
71,
230, 142, 96, 227, 62, 179, 246, 114, 162, 53, 160, 215, 205, 180, 47,
109,
44, 38, 31, 149, 135, 0, 216, 52, 63, 23, 37, 69, 39, 117, 146, 184,
163, 200, 222, 235, 248, 243, 219, 10, 152, 131, 123, 229, 203, 76, 120,
209
};
static struct dm_hash_node *_create_node(const char *str, unsigned len)
{
struct dm_hash_node *n = dm_malloc(sizeof(*n) + len);
if (n) {
memcpy(n->key, str, len);
n->keylen = len;
}
return n;
}
static unsigned long _hash(const char *str, unsigned len)
{
unsigned long h = 0, g;
unsigned i;
for (i = 0; i < len; i++) {
h <<= 4;
h += _nums[(unsigned char) *str++];
g = h & ((unsigned long) 0xf << 16u);
if (g) {
h ^= g >> 16u;
h ^= g >> 5u;
}
}
return h;
}
struct dm_hash_table *dm_hash_create(unsigned size_hint)
{
size_t len;
unsigned new_size = 16u;
struct dm_hash_table *hc = dm_zalloc(sizeof(*hc));
if (!hc)
return_0;
/* round size hint up to a power of two */
while (new_size < size_hint)
new_size = new_size << 1;
hc->num_slots = new_size;
len = sizeof(*(hc->slots)) * new_size;
if (!(hc->slots = dm_malloc(len))) {
stack;
goto bad;
}
memset(hc->slots, 0, len);
return hc;
bad:
dm_free(hc->slots);
dm_free(hc);
return 0;
}
static void _free_nodes(struct dm_hash_table *t)
{
struct dm_hash_node *c, *n;
unsigned i;
for (i = 0; i < t->num_slots; i++)
for (c = t->slots[i]; c; c = n) {
n = c->next;
dm_free(c);
}
}
void dm_hash_destroy(struct dm_hash_table *t)
{
_free_nodes(t);
dm_free(t->slots);
dm_free(t);
}
static struct dm_hash_node **_find(struct dm_hash_table *t, const void *key,
uint32_t len)
{
unsigned h = _hash(key, len) & (t->num_slots - 1);
struct dm_hash_node **c;
for (c = &t->slots[h]; *c; c = &((*c)->next)) {
if ((*c)->keylen != len)
continue;
if (!memcmp(key, (*c)->key, len))
break;
}
return c;
}
void *dm_hash_lookup_binary(struct dm_hash_table *t, const void *key,
uint32_t len)
{
struct dm_hash_node **c = _find(t, key, len);
return *c ? (*c)->data : 0;
}
int dm_hash_insert_binary(struct dm_hash_table *t, const void *key,
uint32_t len, void *data)
{
struct dm_hash_node **c = _find(t, key, len);
if (*c)
(*c)->data = data;
else {
struct dm_hash_node *n = _create_node(key, len);
if (!n)
return 0;
n->data = data;
n->next = 0;
*c = n;
t->num_nodes++;
}
return 1;
}
void dm_hash_remove_binary(struct dm_hash_table *t, const void *key,
uint32_t len)
{
struct dm_hash_node **c = _find(t, key, len);
if (*c) {
struct dm_hash_node *old = *c;
*c = (*c)->next;
dm_free(old);
t->num_nodes--;
}
}
void *dm_hash_lookup(struct dm_hash_table *t, const char *key)
{
return dm_hash_lookup_binary(t, key, strlen(key) + 1);
}
int dm_hash_insert(struct dm_hash_table *t, const char *key, void *data)
{
return dm_hash_insert_binary(t, key, strlen(key) + 1, data);
}
void dm_hash_remove(struct dm_hash_table *t, const char *key)
{
dm_hash_remove_binary(t, key, strlen(key) + 1);
}
unsigned dm_hash_get_num_entries(struct dm_hash_table *t)
{
return t->num_nodes;
}
void dm_hash_iter(struct dm_hash_table *t, dm_hash_iterate_fn f)
{
struct dm_hash_node *c, *n;
unsigned i;
for (i = 0; i < t->num_slots; i++)
for (c = t->slots[i]; c; c = n) {
n = c->next;
f(c->data);
}
}
void dm_hash_wipe(struct dm_hash_table *t)
{
_free_nodes(t);
memset(t->slots, 0, sizeof(struct dm_hash_node *) * t->num_slots);
t->num_nodes = 0u;
}
char *dm_hash_get_key(struct dm_hash_table *t __attribute__((unused)),
struct dm_hash_node *n)
{
return n->key;
}
void *dm_hash_get_data(struct dm_hash_table *t __attribute__((unused)),
struct dm_hash_node *n)
{
return n->data;
}
static struct dm_hash_node *_next_slot(struct dm_hash_table *t, unsigned s)
{
struct dm_hash_node *c = NULL;
unsigned i;
for (i = s; i < t->num_slots && !c; i++)
c = t->slots[i];
return c;
}
struct dm_hash_node *dm_hash_get_first(struct dm_hash_table *t)
{
return _next_slot(t, 0);
}
struct dm_hash_node *dm_hash_get_next(struct dm_hash_table *t, struct dm_hash_node *n)
{
unsigned h = _hash(n->key, n->keylen) & (t->num_slots - 1);
return n->next ? n->next : _next_slot(t, h + 1);
}
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