365 lines
10 KiB
C
365 lines
10 KiB
C
/*
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* Copyright (C) 2008-2011 Teluu Inc. (http://www.teluu.com)
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* Copyright (C) 2003-2008 Benny Prijono <benny@prijono.org>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*/
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#include <pj/hash.h>
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#include <pj/log.h>
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#include <pj/string.h>
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#include <pj/pool.h>
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#include <pj/os.h>
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#include <pj/ctype.h>
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#include <pj/assert.h>
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/**
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* The hash multiplier used to calculate hash value.
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*/
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#define PJ_HASH_MULTIPLIER 33
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struct pj_hash_entry
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{
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struct pj_hash_entry *next;
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void *key;
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pj_uint32_t hash;
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pj_uint32_t keylen;
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void *value;
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};
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struct pj_hash_table_t
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{
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pj_hash_entry **table;
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unsigned count, rows;
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pj_hash_iterator_t iterator;
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};
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PJ_DEF(pj_uint32_t) pj_hash_calc(pj_uint32_t hash, const void *key,
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unsigned keylen)
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{
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PJ_CHECK_STACK();
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if (keylen==PJ_HASH_KEY_STRING) {
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const pj_uint8_t *p = (const pj_uint8_t*)key;
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for ( ; *p; ++p ) {
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hash = (hash * PJ_HASH_MULTIPLIER) + *p;
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}
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} else {
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const pj_uint8_t *p = (const pj_uint8_t*)key,
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*end = p + keylen;
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for ( ; p!=end; ++p) {
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hash = (hash * PJ_HASH_MULTIPLIER) + *p;
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}
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}
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return hash;
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}
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PJ_DEF(pj_uint32_t) pj_hash_calc_tolower( pj_uint32_t hval,
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char *result,
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const pj_str_t *key)
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{
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long i;
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for (i=0; i<key->slen; ++i) {
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int lower = pj_tolower(key->ptr[i]);
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if (result)
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result[i] = (char)lower;
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hval = hval * PJ_HASH_MULTIPLIER + lower;
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}
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return hval;
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}
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PJ_DEF(pj_hash_table_t*) pj_hash_create(pj_pool_t *pool, unsigned size)
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{
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pj_hash_table_t *h;
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unsigned table_size;
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/* Check that PJ_HASH_ENTRY_BUF_SIZE is correct. */
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PJ_ASSERT_RETURN(sizeof(pj_hash_entry)<=PJ_HASH_ENTRY_BUF_SIZE, NULL);
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h = PJ_POOL_ALLOC_T(pool, pj_hash_table_t);
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h->count = 0;
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PJ_LOG( 6, ("hashtbl", "hash table %p created from pool %s", h, pj_pool_getobjname(pool)));
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/* size must be 2^n - 1.
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round-up the size to this rule, except when size is 2^n, then size
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will be round-down to 2^n-1.
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*/
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table_size = 8;
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do {
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table_size <<= 1;
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} while (table_size < size);
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table_size -= 1;
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h->rows = table_size;
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h->table = (pj_hash_entry**)
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pj_pool_calloc(pool, table_size+1, sizeof(pj_hash_entry*));
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return h;
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}
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static pj_hash_entry **find_entry( pj_pool_t *pool, pj_hash_table_t *ht,
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const void *key, unsigned keylen,
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void *val, pj_uint32_t *hval,
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void *entry_buf, pj_bool_t lower)
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{
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pj_uint32_t hash;
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pj_hash_entry **p_entry, *entry;
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if (hval && *hval != 0) {
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hash = *hval;
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if (keylen==PJ_HASH_KEY_STRING) {
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keylen = (unsigned)pj_ansi_strlen((const char*)key);
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}
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} else {
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/* This slightly differs with pj_hash_calc() because we need
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* to get the keylen when keylen is PJ_HASH_KEY_STRING.
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*/
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hash=0;
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if (keylen==PJ_HASH_KEY_STRING) {
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const pj_uint8_t *p = (const pj_uint8_t*)key;
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for ( ; *p; ++p ) {
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if (lower)
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hash = hash * PJ_HASH_MULTIPLIER + pj_tolower(*p);
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else
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hash = hash * PJ_HASH_MULTIPLIER + *p;
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}
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keylen = (unsigned)(p - (const unsigned char*)key);
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} else {
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const pj_uint8_t *p = (const pj_uint8_t*)key,
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*end = p + keylen;
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for ( ; p!=end; ++p) {
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if (lower)
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hash = hash * PJ_HASH_MULTIPLIER + pj_tolower(*p);
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else
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hash = hash * PJ_HASH_MULTIPLIER + *p;
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}
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}
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/* Report back the computed hash. */
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if (hval)
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*hval = hash;
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}
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/* scan the linked list */
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for (p_entry = &ht->table[hash & ht->rows], entry=*p_entry;
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entry;
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p_entry = &entry->next, entry = *p_entry)
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{
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if (entry->hash==hash && entry->keylen==keylen &&
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((lower && pj_ansi_strnicmp((const char*)entry->key,
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(const char*)key, keylen)==0) ||
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(!lower && pj_memcmp(entry->key, key, keylen)==0)))
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{
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break;
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}
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}
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if (entry || val==NULL)
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return p_entry;
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/* Entry not found, create a new one.
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* If entry_buf is specified, use it. Otherwise allocate from pool.
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*/
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if (entry_buf) {
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entry = (pj_hash_entry*)entry_buf;
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} else {
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/* Pool must be specified! */
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PJ_ASSERT_RETURN(pool != NULL, NULL);
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entry = PJ_POOL_ALLOC_T(pool, pj_hash_entry);
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PJ_LOG(6, ("hashtbl",
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"%p: New p_entry %p created, pool used=%lu, cap=%lu",
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ht, entry, (unsigned long)pj_pool_get_used_size(pool),
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(unsigned long)pj_pool_get_capacity(pool)));
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}
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entry->next = NULL;
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entry->hash = hash;
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if (pool) {
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entry->key = pj_pool_alloc(pool, keylen);
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pj_memcpy(entry->key, key, keylen);
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} else {
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entry->key = (void*)key;
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}
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entry->keylen = keylen;
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entry->value = val;
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*p_entry = entry;
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++ht->count;
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return p_entry;
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}
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PJ_DEF(void *) pj_hash_get( pj_hash_table_t *ht,
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const void *key, unsigned keylen,
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pj_uint32_t *hval)
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{
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pj_hash_entry *entry;
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entry = *find_entry( NULL, ht, key, keylen, NULL, hval, NULL, PJ_FALSE);
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return entry ? entry->value : NULL;
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}
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PJ_DEF(void *) pj_hash_get_lower( pj_hash_table_t *ht,
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const void *key, unsigned keylen,
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pj_uint32_t *hval)
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{
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pj_hash_entry *entry;
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entry = *find_entry( NULL, ht, key, keylen, NULL, hval, NULL, PJ_TRUE);
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return entry ? entry->value : NULL;
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}
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static void hash_set( pj_pool_t *pool, pj_hash_table_t *ht,
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const void *key, unsigned keylen, pj_uint32_t hval,
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void *value, void *entry_buf, pj_bool_t lower )
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{
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pj_hash_entry **p_entry;
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p_entry = find_entry( pool, ht, key, keylen, value, &hval, entry_buf,
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lower);
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if (*p_entry) {
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if (value == NULL) {
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/* delete entry */
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PJ_LOG(6, ("hashtbl", "%p: p_entry %p deleted", ht, *p_entry));
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*p_entry = (*p_entry)->next;
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--ht->count;
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} else {
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/* overwrite */
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(*p_entry)->value = value;
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PJ_LOG(6, ("hashtbl", "%p: p_entry %p value set to %p", ht,
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*p_entry, value));
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}
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}
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}
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PJ_DEF(void) pj_hash_set( pj_pool_t *pool, pj_hash_table_t *ht,
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const void *key, unsigned keylen, pj_uint32_t hval,
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void *value )
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{
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hash_set(pool, ht, key, keylen, hval, value, NULL, PJ_FALSE);
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}
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PJ_DEF(void) pj_hash_set_lower( pj_pool_t *pool, pj_hash_table_t *ht,
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const void *key, unsigned keylen,
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pj_uint32_t hval, void *value )
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{
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hash_set(pool, ht, key, keylen, hval, value, NULL, PJ_TRUE);
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}
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PJ_DEF(void) pj_hash_set_np( pj_hash_table_t *ht,
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const void *key, unsigned keylen,
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pj_uint32_t hval, pj_hash_entry_buf entry_buf,
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void *value)
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{
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hash_set(NULL, ht, key, keylen, hval, value, (void *)entry_buf, PJ_FALSE);
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}
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PJ_DEF(void) pj_hash_set_np_lower( pj_hash_table_t *ht,
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const void *key, unsigned keylen,
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pj_uint32_t hval,
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pj_hash_entry_buf entry_buf,
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void *value)
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{
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hash_set(NULL, ht, key, keylen, hval, value, (void *)entry_buf, PJ_TRUE);
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}
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PJ_DEF(unsigned) pj_hash_count( pj_hash_table_t *ht )
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{
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return ht->count;
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}
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PJ_DEF(pj_hash_iterator_t*) pj_hash_first( pj_hash_table_t *ht,
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pj_hash_iterator_t *it )
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{
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it->index = 0;
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it->entry = NULL;
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for (; it->index <= ht->rows; ++it->index) {
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it->entry = ht->table[it->index];
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if (it->entry) {
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break;
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}
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}
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return it->entry ? it : NULL;
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}
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PJ_DEF(pj_hash_iterator_t*) pj_hash_next( pj_hash_table_t *ht,
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pj_hash_iterator_t *it )
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{
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it->entry = it->entry->next;
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if (it->entry) {
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return it;
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}
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for (++it->index; it->index <= ht->rows; ++it->index) {
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it->entry = ht->table[it->index];
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if (it->entry) {
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break;
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}
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}
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return it->entry ? it : NULL;
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}
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PJ_DEF(void*) pj_hash_this( pj_hash_table_t *ht, pj_hash_iterator_t *it )
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{
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PJ_CHECK_STACK();
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PJ_UNUSED_ARG(ht);
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return it->entry->value;
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}
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#if 0
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void pj_hash_dump_collision( pj_hash_table_t *ht )
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{
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unsigned min=0xFFFFFFFF, max=0;
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unsigned i;
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char line[120];
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int len, totlen = 0;
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for (i=0; i<=ht->rows; ++i) {
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unsigned count = 0;
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pj_hash_entry *entry = ht->table[i];
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while (entry) {
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++count;
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entry = entry->next;
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}
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if (count < min)
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min = count;
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if (count > max)
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max = count;
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len = pj_snprintf( line+totlen, sizeof(line)-totlen, "%3d:%3d ", i, count);
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if (len < 1)
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break;
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totlen += len;
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if ((i+1) % 10 == 0) {
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line[totlen] = '\0';
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PJ_LOG(4,(__FILE__, line));
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}
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}
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PJ_LOG(4,(__FILE__,"Count: %d, min: %d, max: %d\n", ht->count, min, max));
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}
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#endif
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