hslot.c

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/*
 * $Id: hslot.c 5241 2008-11-21 12:52:25Z henningw $ 
 *
 * Copyright (C) 2001-2003 FhG Fokus
 *
 * This file is part of Kamailio, a free SIP server.
 *
 * Kamailio is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version
 *
 * Kamailio is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU 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
 */

/*! \file
 *  \brief USRLOC - Hash table collision slot related functions
 *  \ingroup usrloc
 *
 * - Module: \ref usrloc
 */



#include "hslot.h"

/*! number of locks */
int ul_locks_no=4;
/*! global list of locks */
gen_lock_set_t* ul_locks=0;


/*!
 * \brief Initialize locks for the hash table
 * \return 0 on success, -1 on failure
 */
int ul_init_locks(void)
{
   int i;
   i = ul_locks_no;
   do {
      if ((( ul_locks=lock_set_alloc(i))!=0)&&
            (lock_set_init(ul_locks)!=0))
      {
         ul_locks_no = i;
         LM_INFO("locks array size %d\n", ul_locks_no);
         return 0;

      }
      if (ul_locks){
         lock_set_dealloc(ul_locks);
         ul_locks=0;
      }
      i--;
      if(i==0)
      {
         LM_ERR("failed to allocate locks\n");
         return -1;
      }
   } while (1);
}


/*!
 * \brief Unlock all locks on the list
 */
void ul_unlock_locks(void)
{
   unsigned int i;

   if (ul_locks==0)
      return;

   for (i=0;i<ul_locks_no;i++) {
#ifdef GEN_LOCK_T_PREFERED
      lock_release(&ul_locks->locks[i]);
#else
      ul_release_idx(i);
#endif
   };
}


/*!
 * \brief Destroy all locks on the list
 */
void ul_destroy_locks(void)
{
   if (ul_locks !=0){
      lock_set_destroy(ul_locks);
      lock_set_dealloc(ul_locks);
   };
}

#ifndef GEN_LOCK_T_PREFERED
/*!
 * \brief Lock a lock with a certain index
 * \param idx lock index
 */
void ul_lock_idx(int idx)
{
   lock_set_get(ul_locks, idx);
}


/*!
 * \brief Release a lock with a certain index
 * \param idx lock index
 */
void ul_release_idx(int idx)
{
   lock_set_release(ul_locks, idx);
}
#endif

/*!
 * \brief Initialize cache slot structure
 * \param _d domain for the hash slot
 * \param _s hash slot
 * \param n used to get the slot number (modulo number or locks)
 */
void init_slot(struct udomain* _d, hslot_t* _s, int n)
{
   _s->n = 0;
   _s->first = 0;
   _s->last = 0;
   _s->d = _d;

#ifdef GEN_LOCK_T_PREFERED
   _s->lock = &ul_locks->locks[n%ul_locks_no];
#else
   _s->lockidx = n%ul_locks_no;
#endif
}


/*!
 * \brief Deinitialize given slot structure
 * \param _s hash slot
 */
void deinit_slot(hslot_t* _s)
{
   struct urecord* ptr;
   
        /* Remove all elements */
   while(_s->first) {
      ptr = _s->first;
      _s->first = _s->first->next;
      free_urecord(ptr);
   }
   
   _s->n = 0;
   _s->last = 0;
    _s->d = 0;
}


/*!
 * \brief Add an element to an slot's linked list
 * \param _s hash slot
 * \param _r added record
 */
void slot_add(hslot_t* _s, struct urecord* _r)
{
   if (_s->n == 0) {
      _s->first = _s->last = _r;
   } else {
      _r->prev = _s->last;
      _s->last->next = _r;
      _s->last = _r;
   }
   _s->n++;
   _r->slot = _s;
}


/*!
 * \brief Remove an element from slot linked list
 * \param _s hash slot
 * \param _r removed record
 */
void slot_rem(hslot_t* _s, struct urecord* _r)
{
   if (_r->prev) {
      _r->prev->next = _r->next;
   } else {
      _s->first = _r->next;
   }

   if (_r->next) {
      _r->next->prev = _r->prev;
   } else {
      _s->last = _r->prev;
   }

   _r->prev = _r->next = 0;
   _r->slot = 0;
   _s->n--;
}