1
/**************************************************************************
3
* Copyright 2007 VMware, Inc.
6
* Permission is hereby granted, free of charge, to any person obtaining a
7
* copy of this software and associated documentation files (the
8
* "Software"), to deal in the Software without restriction, including
9
* without limitation the rights to use, copy, modify, merge, publish,
10
* distribute, sub license, and/or sell copies of the Software, and to
11
* permit persons to whom the Software is furnished to do so, subject to
12
* the following conditions:
14
* The above copyright notice and this permission notice (including the
15
* next paragraph) shall be included in all copies or substantial portions
18
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
19
* OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
20
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.
21
* IN NO EVENT SHALL VMWARE AND/OR ITS SUPPLIERS BE LIABLE FOR
22
* ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
23
* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
24
* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
26
**************************************************************************/
30
* Zack Rusin <zackr@vmware.com>
33
#include "util/u_debug.h"
34
#include "util/u_memory.h"
39
#define MAX(a, b) ((a > b) ? (a) : (b))
42
static const int MinNumBits = 4;
44
static const unsigned char prime_deltas[] = {
45
0, 0, 1, 3, 1, 5, 3, 3, 1, 9, 7, 5, 3, 9, 25, 3,
46
1, 21, 3, 21, 7, 15, 9, 5, 3, 29, 15, 0, 0, 0, 0, 0
49
static int primeForNumBits(int numBits)
51
return (1 << numBits) + prime_deltas[numBits];
55
Returns the smallest integer n such that
56
primeForNumBits(n) >= hint.
58
static int countBits(int hint)
68
if (numBits >= (int)sizeof(prime_deltas)) {
69
numBits = sizeof(prime_deltas) - 1;
70
} else if (primeForNumBits(numBits) < hint) {
76
static struct cso_node *
77
cso_hash_create_node(struct cso_hash *hash,
78
unsigned akey, void *avalue,
79
struct cso_node **anextNode)
81
struct cso_node *node = MALLOC(sizeof(struct cso_node));
89
node->next = *anextNode;
95
static void cso_data_rehash(struct cso_hash *hash, int hint)
98
hint = countBits(-hint);
99
if (hint < MinNumBits)
101
hash->userNumBits = (short)hint;
102
while (primeForNumBits(hint) < (hash->size >> 1))
104
} else if (hint < MinNumBits) {
108
if (hash->numBits != hint) {
109
struct cso_node *e = (struct cso_node *)hash;
110
struct cso_node **oldBuckets = hash->buckets;
111
int oldNumBuckets = hash->numBuckets;
114
hash->numBits = (short)hint;
115
hash->numBuckets = primeForNumBits(hint);
116
hash->buckets = MALLOC(sizeof(struct cso_node*) * hash->numBuckets);
117
for (i = 0; i < hash->numBuckets; ++i)
118
hash->buckets[i] = e;
120
for (i = 0; i < oldNumBuckets; ++i) {
121
struct cso_node *firstNode = oldBuckets[i];
122
while (firstNode != e) {
123
unsigned h = firstNode->key;
124
struct cso_node *lastNode = firstNode;
125
struct cso_node *afterLastNode;
126
struct cso_node **beforeFirstNode;
128
while (lastNode->next != e && lastNode->next->key == h)
129
lastNode = lastNode->next;
131
afterLastNode = lastNode->next;
132
beforeFirstNode = &hash->buckets[h % hash->numBuckets];
133
while (*beforeFirstNode != e)
134
beforeFirstNode = &(*beforeFirstNode)->next;
135
lastNode->next = *beforeFirstNode;
136
*beforeFirstNode = firstNode;
137
firstNode = afterLastNode;
144
static void cso_data_might_grow(struct cso_hash *hash)
146
if (hash->size >= hash->numBuckets)
147
cso_data_rehash(hash, hash->numBits + 1);
150
static void cso_data_has_shrunk(struct cso_hash *hash)
152
if (hash->size <= (hash->numBuckets >> 3) &&
153
hash->numBits > hash->userNumBits) {
154
int max = MAX(hash->numBits-2, hash->userNumBits);
155
cso_data_rehash(hash, max);
159
static struct cso_node *cso_data_first_node(struct cso_hash *hash)
161
struct cso_node *e = (struct cso_node *)hash;
162
struct cso_node **bucket = hash->buckets;
163
int n = hash->numBuckets;
173
struct cso_hash_iter cso_hash_insert(struct cso_hash *hash,
174
unsigned key, void *data)
176
cso_data_might_grow(hash);
178
struct cso_node **nextNode = cso_hash_find_node(hash, key);
179
struct cso_node *node = cso_hash_create_node(hash, key, data, nextNode);
181
struct cso_hash_iter null_iter = {hash, NULL};
185
struct cso_hash_iter iter = {hash, node};
189
void cso_hash_init(struct cso_hash *hash)
191
hash->fakeNext = NULL;
192
hash->buckets = NULL;
194
hash->userNumBits = (short)MinNumBits;
196
hash->numBuckets = 0;
197
hash->end = (struct cso_node*)hash;
200
void cso_hash_deinit(struct cso_hash *hash)
202
struct cso_node *e_for_x = hash->end;
203
struct cso_node **bucket = hash->buckets;
204
int n = hash->numBuckets;
207
struct cso_node *cur = *bucket++;
208
while (cur != e_for_x) {
209
struct cso_node *next = cur->next;
217
unsigned cso_hash_iter_key(struct cso_hash_iter iter)
219
if (!iter.node || iter.hash->end == iter.node)
221
return iter.node->key;
224
struct cso_node *cso_hash_data_next(struct cso_node *node)
227
struct cso_node *next;
232
struct cso_node **bucket;
237
debug_printf("iterating beyond the last element\n");
243
start = (node->key % a.d->numBuckets) + 1;
244
bucket = a.d->buckets + start;
245
n = a.d->numBuckets - start;
254
void *cso_hash_take(struct cso_hash *hash, unsigned akey)
256
struct cso_node **node = cso_hash_find_node(hash, akey);
258
if (*node != hash->end) {
259
void *t = (*node)->value;
260
struct cso_node *next = (*node)->next;
264
cso_data_has_shrunk(hash);
270
struct cso_hash_iter cso_hash_first_node(struct cso_hash *hash)
272
struct cso_hash_iter iter = {hash, cso_data_first_node(hash)};
276
int cso_hash_size(struct cso_hash *hash)
281
struct cso_hash_iter cso_hash_erase(struct cso_hash *hash, struct cso_hash_iter iter)
283
struct cso_hash_iter ret = iter;
284
struct cso_node *node = iter.node;
285
struct cso_node **node_ptr;
287
if (node == hash->end)
290
ret = cso_hash_iter_next(ret);
291
node_ptr = &hash->buckets[node->key % hash->numBuckets];
292
while (*node_ptr != node)
293
node_ptr = &(*node_ptr)->next;
294
*node_ptr = node->next;
300
bool cso_hash_contains(struct cso_hash *hash, unsigned key)
302
struct cso_node **node = cso_hash_find_node(hash, key);
303
return *node != hash->end;