epan/slab.h

   1 /* slab.h
   2  * Definitions for very simple slab handling
   3  *
   4  * $Id: slab.h,v 1.2 2003/12/03 08:53:36 guy Exp $
   5  *
   6  * Ethereal - Network traffic analyzer
   7  * By Gerald Combs <gerald@ethereal.com>
   8  * Copyright 1998 Gerald Combs
   9  *
  10  * This program is free software; you can redistribute it and/or
  11  * modify it under the terms of the GNU General Public License
  12  * as published by the Free Software Foundation; either version 2
  13  * of the License, or (at your option) any later version.
  14  *
  15  * This program is distributed in the hope that it will be useful,
  16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18  * GNU General Public License for more details.
  19  *
  20  * You should have received a copy of the GNU General Public License
  21  * along with this program; if not, write to the Free Software
  22  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
  23  */
  24
  25 #ifndef __SLAB_H__
  26 #define __SLAB_H__
  27
  28 #define NITEMS_PER_SLAB 100
  29
  30 typedef struct _freed_item {
  31         struct _freed_item *next;
  32 } freed_item_t;
  33
  34 /* we never free any memory we have allocated, when it is returned to us
  35    we just store it in the free list until (hopefully) it gets used again
  36 */
  37 #define SLAB_ALLOC(item, list)                                  \
  38         if(!list){                                              \
  39                 int i;                                          \
  40                 char *tmp;                                      \
  41                 tmp=(char *)g_malloc(NITEMS_PER_SLAB*           \
  42                     ((sizeof(*item) > sizeof(freed_item_t)) ?   \
  43                         sizeof(*item) : sizeof(freed_item_t))); \
  44                 for(i=0;i<NITEMS_PER_SLAB;i++){                 \
  45                         item=(void *)tmp;                       \
  46                         ((freed_item_t *)((void *)item))->next= \
  47                             (freed_item_t *)((void *)list);     \
  48                         list=item;                              \
  49                         tmp+=                                   \
  50                             ((sizeof(*item) > sizeof(freed_item_t)) ?\
  51                                 sizeof(*item) : sizeof(freed_item_t));\
  52                 }                                               \
  53         }                                                       \
  54         item=list;                                              \
  55         list=(void *)(((freed_item_t *)((void *)item))->next);
  56
  57 #define SLAB_FREE(item, list)                           \
  58 {                                                       \
  59         ((freed_item_t *)((void *)item))->next=         \
  60             (freed_item_t *)((void *)list);             \
  61         list=item;                                      \
  62 }
  63
  64 #endif /* slab.h */