mdw@git.distorted.org.uk Git - mLib/blob - arena.h

   1 /* -*-c-*-
   2  *
   3  * $Id$
   4  *
   5  * Abstraction for memory allocation arenas
   6  *
   7  * (c) 2000 Straylight/Edgeware
   8  */
   9
  10 /*----- Licensing notice --------------------------------------------------*
  11  *
  12  * This file is part of the mLib utilities library.
  13  *
  14  * mLib is free software; you can redistribute it and/or modify
  15  * it under the terms of the GNU Library General Public License as
  16  * published by the Free Software Foundation; either version 2 of the
  17  * License, or (at your option) any later version.
  18  *
  19  * mLib is distributed in the hope that it will be useful,
  20  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  21  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  22  * GNU Library General Public License for more details.
  23  *
  24  * You should have received a copy of the GNU Library General Public
  25  * License along with mLib; if not, write to the Free
  26  * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
  27  * MA 02111-1307, USA.
  28  */
  29
  30 #ifndef MLIB_ARENA_H
  31 #define MLIB_ARENA_H
  32
  33 #ifdef __cplusplus
  34   extern "C" {
  35 #endif
  36
  37 /*----- Header files ------------------------------------------------------*/
  38
  39 #include <stdlib.h>
  40
  41 /*----- Data structures ---------------------------------------------------*/
  42
  43 /* --- An arena structure --- */
  44
  45 typedef struct arena {
  46   const struct arena_ops *ops;
  47 } arena;
  48
  49 typedef struct arena_ops {
  50   void *(*alloc)(arena */*a*/, size_t /*sz*/);
  51   void *(*realloc)(arena */*a*/, void */*p*/, size_t /*sz*/, size_t /*osz*/);
  52   void (*free)(arena */*a*/, void */*p*/);
  53   void (*purge)(arena */*a*/);
  54 } arena_ops;
  55
  56 /*----- Global variables --------------------------------------------------*/
  57
  58 extern arena *arena_global;             /* Standard global arena */
  59 extern arena arena_stdlib;              /* Arena based on @malloc@/@free@ */
  60
  61 /*----- Functions provided ------------------------------------------------*/
  62
  63 /* --- @arena_fakerealloc@ --- *
  64  *
  65  * Arguments:   @arena *a@ = pointer to arena block
  66  *              @void *p@ = pointer to memory block to resize
  67  *              @size_t sz@ = size desired for the block
  68  *              @size_t osz@ = size of the old block
  69  *
  70  * Returns:     ---
  71  *
  72  * Use:         Standard fake @realloc@ function, for use if you don't
  73  *              support @realloc@ properly.
  74  */
  75
  76 extern void *arena_fakerealloc(arena */*a*/, void */*p*/,
  77                                size_t /*sz*/, size_t /*osz*/);
  78
  79 /* --- Useful macros --- */
  80
  81 #define A_ALLOC(a, sz) (((a)->ops->alloc)((a), (sz)))
  82 #define A_REALLOC(a, p, sz, osz) (((a)->ops->realloc)((a), (p), (sz), (osz)))
  83 #define A_FREE(a, p) (((a)->ops->free)((a), (p)))
  84
  85 /* --- Simple function equivalents --- */
  86
  87 extern void *a_alloc(arena */*a*/, size_t /*sz*/);
  88 extern void *a_realloc(arena */*a*/, void */*p*/,
  89                        size_t /*sz*/, size_t /*osz*/);
  90 extern void a_free(arena */*a*/, void */*p*/);
  91
  92 /*----- That's all, folks -------------------------------------------------*/
  93
  94 #ifdef __cplusplus
  95   }
  96 #endif
  97
  98 #endif