Benny Prijono | e722461 | 2005-11-13 19:40:44 +0000 | [diff] [blame^] | 1 | /* $Id$
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| 2 | */
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| 3 | /*
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| 4 | * PJLIB - PJ Foundation Library
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| 5 | * (C)2003-2005 Benny Prijono <bennylp@bulukucing.org>
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| 6 | *
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| 7 | * Author:
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| 8 | * Benny Prijono <bennylp@bulukucing.org>
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| 9 | *
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| 10 | * This library is free software; you can redistribute it and/or
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| 11 | * modify it under the terms of the GNU Lesser General Public
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| 12 | * License as published by the Free Software Foundation; either
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| 13 | * version 2.1 of the License, or (at your option) any later version.
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| 14 | *
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| 15 | * This library is distributed in the hope that it will be useful,
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| 16 | * but WITHOUT ANY WARRANTY; without even the implied warranty of
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| 17 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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| 18 | * Lesser General Public License for more details.
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| 19 | *
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| 20 | * You should have received a copy of the GNU Lesser General Public
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| 21 | * License along with this library; if not, write to the Free Software
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| 22 | * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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| 23 | */
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| 24 | #include <pj/hash.h>
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| 25 | #include <pj/log.h>
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| 26 | #include <pj/string.h>
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| 27 | #include <pj/pool.h>
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| 28 | #include <pj/os.h>
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| 29 | #include <pj/ctype.h>
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| 30 |
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| 31 | /**
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| 32 | * The hash multiplier used to calculate hash value.
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| 33 | */
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| 34 | #define PJ_HASH_MULTIPLIER 33
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| 35 |
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| 36 |
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| 37 | struct pj_hash_entry
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| 38 | {
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| 39 | struct pj_hash_entry *next;
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| 40 | const void *key;
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| 41 | pj_uint32_t hash;
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| 42 | pj_uint32_t keylen;
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| 43 | void *value;
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| 44 | };
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| 45 |
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| 46 |
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| 47 | struct pj_hash_table_t
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| 48 | {
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| 49 | pj_hash_entry **table;
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| 50 | unsigned count, rows;
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| 51 | pj_hash_iterator_t iterator;
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| 52 | };
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| 53 |
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| 54 |
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| 55 |
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| 56 | PJ_DEF(pj_uint32_t) pj_hash_calc(pj_uint32_t hash, const void *key, unsigned keylen)
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| 57 | {
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| 58 | PJ_CHECK_STACK();
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| 59 |
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| 60 | if (keylen==PJ_HASH_KEY_STRING) {
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| 61 | const unsigned char *p = key;
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| 62 | for ( ; *p; ++p ) {
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| 63 | hash = hash * PJ_HASH_MULTIPLIER + *p;
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| 64 | }
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| 65 | keylen = p - (const unsigned char*)key;
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| 66 | } else {
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| 67 | const unsigned char *p = key,
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| 68 | *end = p + keylen;
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| 69 | for ( ; p!=end; ++p) {
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| 70 | hash = hash * PJ_HASH_MULTIPLIER + *p;
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| 71 | }
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| 72 | }
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| 73 | return hash;
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| 74 | }
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Benny Prijono | f010e69 | 2005-11-11 19:01:31 +0000 | [diff] [blame] | 75 |
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| 76 | PJ_DEF(pj_uint32_t) pj_hash_calc_tolower( pj_uint32_t hval,
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| 77 | char *result,
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| 78 | const pj_str_t *key)
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| 79 | {
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| 80 | long i;
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| 81 |
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| 82 | for (i=0; i<key->slen; ++i) {
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| 83 | result[i] = (char)pj_tolower(key->ptr[i]);
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| 84 | hval = hval * PJ_HASH_MULTIPLIER + result[i];
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| 85 | }
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| 86 |
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| 87 | return hval;
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| 88 | }
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Benny Prijono | e722461 | 2005-11-13 19:40:44 +0000 | [diff] [blame^] | 89 |
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| 90 |
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| 91 | PJ_DEF(pj_hash_table_t*) pj_hash_create(pj_pool_t *pool, unsigned size)
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| 92 | {
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| 93 | pj_hash_table_t *h;
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| 94 | unsigned table_size;
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| 95 |
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| 96 | h = pj_pool_alloc(pool, sizeof(pj_hash_table_t));
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| 97 | h->count = 0;
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| 98 |
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| 99 | PJ_LOG( 5, ("hashtbl", "hash table %p created from pool %s", h, pj_pool_getobjname(pool)));
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| 100 |
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| 101 | /* size must be 2^n - 1.
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| 102 | round-up the size to this rule, except when size is 2^n, then size
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| 103 | will be round-down to 2^n-1.
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| 104 | */
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| 105 | table_size = 8;
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| 106 | do {
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| 107 | table_size <<= 1;
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| 108 | } while (table_size <= size);
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| 109 | table_size -= 1;
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| 110 |
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| 111 | h->rows = table_size;
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| 112 | h->table = pj_pool_calloc(pool, table_size+1, sizeof(pj_hash_entry*));
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| 113 | return h;
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| 114 | }
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| 115 |
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| 116 | static pj_hash_entry **find_entry( pj_pool_t *pool, pj_hash_table_t *ht,
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| 117 | const void *key, unsigned keylen,
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| 118 | void *val)
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| 119 | {
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| 120 | pj_uint32_t hash;
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| 121 | pj_hash_entry **p_entry, *entry;
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| 122 |
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| 123 | hash=0;
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| 124 | if (keylen==PJ_HASH_KEY_STRING) {
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| 125 | const unsigned char *p = key;
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| 126 | for ( ; *p; ++p ) {
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| 127 | hash = hash * PJ_HASH_MULTIPLIER + *p;
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| 128 | }
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| 129 | keylen = p - (const unsigned char*)key;
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| 130 | } else {
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| 131 | const unsigned char *p = key,
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| 132 | *end = p + keylen;
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| 133 | for ( ; p!=end; ++p) {
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| 134 | hash = hash * PJ_HASH_MULTIPLIER + *p;
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| 135 | }
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| 136 | }
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| 137 |
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| 138 | /* scan the linked list */
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| 139 | for (p_entry = &ht->table[hash & ht->rows], entry=*p_entry;
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| 140 | entry;
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| 141 | p_entry = &entry->next, entry = *p_entry)
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| 142 | {
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| 143 | if (entry->hash==hash && entry->keylen==keylen &&
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| 144 | memcmp(entry->key, key, keylen)==0)
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| 145 | {
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| 146 | break;
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| 147 | }
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| 148 | }
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| 149 |
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| 150 | if (entry || val==NULL)
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| 151 | return p_entry;
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| 152 |
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| 153 | /* create a new entry */
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| 154 | entry = pj_pool_alloc(pool, sizeof(pj_hash_entry));
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| 155 | PJ_LOG(5, ("hashtbl", "%p: New p_entry %p created, pool used=%u, cap=%u", ht, entry,
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| 156 | pj_pool_get_used_size(pool), pj_pool_get_capacity(pool)));
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| 157 | entry->next = NULL;
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| 158 | entry->hash = hash;
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| 159 | entry->key = key;
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| 160 | entry->keylen = keylen;
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| 161 | entry->value = val;
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| 162 | *p_entry = entry;
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| 163 |
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| 164 | ++ht->count;
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| 165 |
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| 166 | return p_entry;
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| 167 | }
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| 168 |
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| 169 | PJ_DEF(void *) pj_hash_get( pj_hash_table_t *ht,
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| 170 | const void *key, unsigned keylen )
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| 171 | {
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| 172 | pj_hash_entry *entry;
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| 173 | entry = *find_entry( NULL, ht, key, keylen, NULL);
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| 174 | return entry ? entry->value : NULL;
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| 175 | }
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| 176 |
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| 177 | PJ_DEF(void) pj_hash_set( pj_pool_t *pool, pj_hash_table_t *ht,
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| 178 | const void *key, unsigned keylen,
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| 179 | void *value )
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| 180 | {
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| 181 | pj_hash_entry **p_entry;
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| 182 |
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| 183 | p_entry = find_entry( pool, ht, key, keylen, value );
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| 184 | if (*p_entry) {
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| 185 | if (value == NULL) {
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| 186 | /* delete entry */
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| 187 | PJ_LOG(5, ("hashtbl", "%p: p_entry %p deleted", ht, *p_entry));
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| 188 | *p_entry = (*p_entry)->next;
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| 189 | --ht->count;
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| 190 |
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| 191 | } else {
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| 192 | /* overwrite */
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| 193 | (*p_entry)->value = value;
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| 194 | PJ_LOG(5, ("hashtbl", "%p: p_entry %p value set to %p", ht, *p_entry, value));
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| 195 | }
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| 196 | }
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| 197 | }
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| 198 |
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| 199 | PJ_DEF(unsigned) pj_hash_count( pj_hash_table_t *ht )
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| 200 | {
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| 201 | return ht->count;
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| 202 | }
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| 203 |
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| 204 | PJ_DEF(pj_hash_iterator_t*) pj_hash_first( pj_hash_table_t *ht,
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| 205 | pj_hash_iterator_t *it )
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| 206 | {
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| 207 | it->index = 0;
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| 208 | it->entry = NULL;
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| 209 |
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| 210 | for (; it->index < ht->rows; ++it->index) {
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| 211 | it->entry = ht->table[it->index];
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| 212 | if (it->entry) {
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| 213 | break;
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| 214 | }
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| 215 | }
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| 216 |
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| 217 | return it->entry ? it : NULL;
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| 218 | }
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| 219 |
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| 220 | PJ_DEF(pj_hash_iterator_t*) pj_hash_next( pj_hash_table_t *ht,
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| 221 | pj_hash_iterator_t *it )
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| 222 | {
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| 223 | it->entry = it->entry->next;
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| 224 | if (it->entry) {
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| 225 | return it;
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| 226 | }
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| 227 |
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| 228 | for (++it->index; it->index < ht->rows; ++it->index) {
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| 229 | it->entry = ht->table[it->index];
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| 230 | if (it->entry) {
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| 231 | break;
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| 232 | }
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| 233 | }
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| 234 |
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| 235 | return it->entry ? it : NULL;
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| 236 | }
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| 237 |
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| 238 | PJ_DEF(void*) pj_hash_this( pj_hash_table_t *ht, pj_hash_iterator_t *it )
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| 239 | {
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| 240 | PJ_CHECK_STACK();
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| 241 | PJ_UNUSED_ARG(ht);
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| 242 | return it->entry->value;
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| 243 | }
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| 244 |
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| 245 | #if 0
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| 246 | void pj_hash_dump_collision( pj_hash_table_t *ht )
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| 247 | {
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| 248 | unsigned min=0xFFFFFFFF, max=0;
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| 249 | unsigned i;
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| 250 | char line[120];
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| 251 | int len, totlen = 0;
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| 252 |
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| 253 | for (i=0; i<ht->rows; ++i) {
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| 254 | unsigned count = 0;
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| 255 | pj_hash_entry *entry = ht->table[i];
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| 256 | while (entry) {
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| 257 | ++count;
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| 258 | entry = entry->next;
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| 259 | }
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| 260 | if (count < min)
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| 261 | min = count;
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| 262 | if (count > max)
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| 263 | max = count;
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| 264 | len = pj_snprintf( line+totlen, sizeof(line)-totlen, "%3d:%3d ", i, count);
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| 265 | if (len < 1)
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| 266 | break;
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| 267 | totlen += len;
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| 268 |
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| 269 | if ((i+1) % 10 == 0) {
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| 270 | line[totlen] = '\0';
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| 271 | PJ_LOG(4,(__FILE__, line));
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| 272 | }
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| 273 | }
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| 274 |
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| 275 | PJ_LOG(4,(__FILE__,"Count: %d, min: %d, max: %d\n", ht->count, min, max));
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| 276 | }
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| 277 | #endif
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| 278 |
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| 279 |
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