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d9295410e9
If the data len is passed into the hash table and saved there, then the hash table internals do not need to assume that the data value is a string at any point.
405 lines
8.8 KiB
C
405 lines
8.8 KiB
C
/*
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* Copyright (C) 2001-2004 Sistina Software, Inc. All rights reserved.
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* Copyright (C) 2004-2011 Red Hat, Inc. All rights reserved.
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*
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* This file is part of the device-mapper userspace tools.
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*
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* This copyrighted material is made available to anyone wishing to use,
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* modify, copy, or redistribute it subject to the terms and conditions
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* of the GNU Lesser General Public License v.2.1.
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*
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* You should have received a copy of the GNU Lesser General Public License
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* along with this program; if not, write to the Free Software Foundation,
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* Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*/
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#include "dmlib.h"
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struct dm_hash_node {
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struct dm_hash_node *next;
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void *data;
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unsigned data_len;
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unsigned keylen;
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char key[0];
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};
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struct dm_hash_table {
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unsigned num_nodes;
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unsigned num_slots;
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struct dm_hash_node **slots;
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};
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/* Permutation of the Integers 0 through 255 */
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static unsigned char _nums[] = {
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1, 14, 110, 25, 97, 174, 132, 119, 138, 170, 125, 118, 27, 233, 140, 51,
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87, 197, 177, 107, 234, 169, 56, 68, 30, 7, 173, 73, 188, 40, 36, 65,
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49, 213, 104, 190, 57, 211, 148, 223, 48, 115, 15, 2, 67, 186, 210, 28,
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12, 181, 103, 70, 22, 58, 75, 78, 183, 167, 238, 157, 124, 147, 172,
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144,
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176, 161, 141, 86, 60, 66, 128, 83, 156, 241, 79, 46, 168, 198, 41, 254,
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178, 85, 253, 237, 250, 154, 133, 88, 35, 206, 95, 116, 252, 192, 54,
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221,
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102, 218, 255, 240, 82, 106, 158, 201, 61, 3, 89, 9, 42, 155, 159, 93,
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166, 80, 50, 34, 175, 195, 100, 99, 26, 150, 16, 145, 4, 33, 8, 189,
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121, 64, 77, 72, 208, 245, 130, 122, 143, 55, 105, 134, 29, 164, 185,
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194,
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193, 239, 101, 242, 5, 171, 126, 11, 74, 59, 137, 228, 108, 191, 232,
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139,
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6, 24, 81, 20, 127, 17, 91, 92, 251, 151, 225, 207, 21, 98, 113, 112,
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84, 226, 18, 214, 199, 187, 13, 32, 94, 220, 224, 212, 247, 204, 196,
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43,
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249, 236, 45, 244, 111, 182, 153, 136, 129, 90, 217, 202, 19, 165, 231,
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71,
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230, 142, 96, 227, 62, 179, 246, 114, 162, 53, 160, 215, 205, 180, 47,
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109,
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44, 38, 31, 149, 135, 0, 216, 52, 63, 23, 37, 69, 39, 117, 146, 184,
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163, 200, 222, 235, 248, 243, 219, 10, 152, 131, 123, 229, 203, 76, 120,
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209
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};
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static struct dm_hash_node *_create_node(const char *str, unsigned len)
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{
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struct dm_hash_node *n = dm_malloc(sizeof(*n) + len);
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if (n) {
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memcpy(n->key, str, len);
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n->keylen = len;
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}
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return n;
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}
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static unsigned long _hash(const char *str, unsigned len)
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{
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unsigned long h = 0, g;
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unsigned i;
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for (i = 0; i < len; i++) {
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h <<= 4;
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h += _nums[(unsigned char) *str++];
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g = h & ((unsigned long) 0xf << 16u);
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if (g) {
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h ^= g >> 16u;
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h ^= g >> 5u;
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}
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}
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return h;
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}
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struct dm_hash_table *dm_hash_create(unsigned size_hint)
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{
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size_t len;
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unsigned new_size = 16u;
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struct dm_hash_table *hc = dm_zalloc(sizeof(*hc));
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if (!hc)
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return_0;
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/* round size hint up to a power of two */
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while (new_size < size_hint)
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new_size = new_size << 1;
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hc->num_slots = new_size;
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len = sizeof(*(hc->slots)) * new_size;
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if (!(hc->slots = dm_malloc(len))) {
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stack;
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goto bad;
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}
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memset(hc->slots, 0, len);
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return hc;
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bad:
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dm_free(hc->slots);
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dm_free(hc);
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return 0;
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}
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static void _free_nodes(struct dm_hash_table *t)
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{
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struct dm_hash_node *c, *n;
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unsigned i;
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for (i = 0; i < t->num_slots; i++)
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for (c = t->slots[i]; c; c = n) {
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n = c->next;
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dm_free(c);
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}
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}
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void dm_hash_destroy(struct dm_hash_table *t)
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{
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_free_nodes(t);
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dm_free(t->slots);
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dm_free(t);
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}
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static struct dm_hash_node **_find(struct dm_hash_table *t, const void *key,
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uint32_t len)
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{
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unsigned h = _hash(key, len) & (t->num_slots - 1);
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struct dm_hash_node **c;
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for (c = &t->slots[h]; *c; c = &((*c)->next)) {
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if ((*c)->keylen != len)
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continue;
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if (!memcmp(key, (*c)->key, len))
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break;
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}
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return c;
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}
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void *dm_hash_lookup_binary(struct dm_hash_table *t, const void *key,
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uint32_t len)
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{
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struct dm_hash_node **c = _find(t, key, len);
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return *c ? (*c)->data : 0;
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}
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int dm_hash_insert_binary(struct dm_hash_table *t, const void *key,
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uint32_t len, void *data)
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{
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struct dm_hash_node **c = _find(t, key, len);
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if (*c)
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(*c)->data = data;
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else {
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struct dm_hash_node *n = _create_node(key, len);
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if (!n)
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return 0;
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n->data = data;
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n->next = 0;
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*c = n;
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t->num_nodes++;
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}
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return 1;
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}
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void dm_hash_remove_binary(struct dm_hash_table *t, const void *key,
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uint32_t len)
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{
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struct dm_hash_node **c = _find(t, key, len);
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if (*c) {
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struct dm_hash_node *old = *c;
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*c = (*c)->next;
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dm_free(old);
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t->num_nodes--;
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}
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}
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void *dm_hash_lookup(struct dm_hash_table *t, const char *key)
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{
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return dm_hash_lookup_binary(t, key, strlen(key) + 1);
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}
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int dm_hash_insert(struct dm_hash_table *t, const char *key, void *data)
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{
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return dm_hash_insert_binary(t, key, strlen(key) + 1, data);
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}
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void dm_hash_remove(struct dm_hash_table *t, const char *key)
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{
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dm_hash_remove_binary(t, key, strlen(key) + 1);
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}
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static struct dm_hash_node **_find_str_withval(struct dm_hash_table *t,
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const void *key, const void *val,
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uint32_t len, uint32_t val_len)
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{
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struct dm_hash_node **c;
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unsigned h;
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h = _hash(key, len) & (t->num_slots - 1);
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for (c = &t->slots[h]; *c; c = &((*c)->next)) {
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if ((*c)->keylen != len)
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continue;
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if (!memcmp(key, (*c)->key, len) && (*c)->data) {
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if (((*c)->data_len == val_len) &&
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!memcmp(val, (*c)->data, val_len))
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return c;
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}
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}
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return NULL;
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}
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int dm_hash_insert_multival(struct dm_hash_table *t, const char *key,
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const void *val, uint32_t val_len)
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{
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struct dm_hash_node *n;
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struct dm_hash_node *first;
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int len = strlen(key) + 1;
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unsigned h;
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n = _create_node(key, len);
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if (!n)
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return 0;
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n->data = (void *)val;
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n->data_len = val_len;
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h = _hash(key, len) & (t->num_slots - 1);
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first = t->slots[h];
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if (first)
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n->next = first;
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else
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n->next = 0;
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t->slots[h] = n;
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t->num_nodes++;
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return 1;
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}
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/*
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* Look through multiple entries with the same key for one that has a
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* matching val and return that. If none have maching val, return NULL.
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*/
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void *dm_hash_lookup_withval(struct dm_hash_table *t, const char *key,
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const void *val, uint32_t val_len)
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{
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struct dm_hash_node **c;
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c = _find_str_withval(t, key, val, strlen(key) + 1, val_len);
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return (c && *c) ? (*c)->data : 0;
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}
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/*
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* Look through multiple entries with the same key for one that has a
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* matching val and remove that.
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*/
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void dm_hash_remove_withval(struct dm_hash_table *t, const char *key,
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const void *val, uint32_t val_len)
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{
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struct dm_hash_node **c;
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c = _find_str_withval(t, key, val, strlen(key) + 1, val_len);
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if (c && *c) {
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struct dm_hash_node *old = *c;
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*c = (*c)->next;
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dm_free(old);
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t->num_nodes--;
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}
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}
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/*
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* Look for multiple entries with the same key.
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*
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* If no entries have key, return NULL.
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*
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* If one entry has the key, the function returns the val,
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* and sets val2 to NULL.
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*
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* If two entries have the key, the function returns the val
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* from the first entry, and the val2 arg is set to the val
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* from the second entry.
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*
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* If more than two entries have the key, the function looks
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* at only the first two.
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*/
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void *dm_hash_lookup_multival(struct dm_hash_table *t, const char *key, const void **val2)
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{
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struct dm_hash_node **c;
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struct dm_hash_node **c1 = NULL;
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struct dm_hash_node **c2 = NULL;
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uint32_t len = strlen(key) + 1;
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unsigned h;
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h = _hash(key, len) & (t->num_slots - 1);
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for (c = &t->slots[h]; *c; c = &((*c)->next)) {
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if ((*c)->keylen != len)
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continue;
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if (!memcmp(key, (*c)->key, len)) {
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if (!c1) {
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c1 = c;
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} else if (!c2) {
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c2 = c;
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break;
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}
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}
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}
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if (!c2)
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*val2 = NULL;
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else
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*val2 = (*c2)->data;
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if (!c1)
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return NULL;
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else
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return *c1 ? (*c1)->data : 0;
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}
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unsigned dm_hash_get_num_entries(struct dm_hash_table *t)
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{
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return t->num_nodes;
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}
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void dm_hash_iter(struct dm_hash_table *t, dm_hash_iterate_fn f)
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{
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struct dm_hash_node *c, *n;
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unsigned i;
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for (i = 0; i < t->num_slots; i++)
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for (c = t->slots[i]; c; c = n) {
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n = c->next;
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f(c->data);
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}
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}
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void dm_hash_wipe(struct dm_hash_table *t)
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{
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_free_nodes(t);
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memset(t->slots, 0, sizeof(struct dm_hash_node *) * t->num_slots);
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t->num_nodes = 0u;
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}
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char *dm_hash_get_key(struct dm_hash_table *t __attribute__((unused)),
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struct dm_hash_node *n)
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{
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return n->key;
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}
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void *dm_hash_get_data(struct dm_hash_table *t __attribute__((unused)),
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struct dm_hash_node *n)
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{
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return n->data;
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}
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static struct dm_hash_node *_next_slot(struct dm_hash_table *t, unsigned s)
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{
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struct dm_hash_node *c = NULL;
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unsigned i;
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for (i = s; i < t->num_slots && !c; i++)
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c = t->slots[i];
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return c;
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}
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struct dm_hash_node *dm_hash_get_first(struct dm_hash_table *t)
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{
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return _next_slot(t, 0);
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}
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struct dm_hash_node *dm_hash_get_next(struct dm_hash_table *t, struct dm_hash_node *n)
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{
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unsigned h = _hash(n->key, n->keylen) & (t->num_slots - 1);
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return n->next ? n->next : _next_slot(t, h + 1);
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}
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