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

   1 /* -*-c-*-
   2  *
   3  * $Id: arena.h,v 1.2 2000/07/16 12:29:16 mdw Exp $
   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 /*----- Revision history --------------------------------------------------*
  31  *
  32  * $Log: arena.h,v $
  33  * Revision 1.2  2000/07/16 12:29:16  mdw
  34  * Change to arena `realloc' interface, to fix a design bug.
  35  *
  36  * Revision 1.1  2000/06/17 10:37:53  mdw
  37  * Basic arena management.
  38  *
  39  */
  40
  41 #ifndef MLIB_ARENA_H
  42 #define MLIB_ARENA_H
  43
  44 #ifdef __cplusplus
  45   extern "C" {
  46 #endif
  47
  48 /*----- Header files ------------------------------------------------------*/
  49
  50 #include <stdlib.h>
  51
  52 /*----- Data structures ---------------------------------------------------*/
  53
  54 /* --- An arena structure --- */
  55
  56 typedef struct arena {
  57   struct arena_ops *ops;
  58 } arena;
  59
  60 typedef struct arena_ops {
  61   void *(*alloc)(arena */*a*/, size_t /*sz*/);
  62   void *(*realloc)(arena */*a*/, void */*p*/, size_t /*sz*/, size_t /*osz*/);
  63   void (*free)(arena */*a*/, void */*p*/);
  64   void (*purge)(arena */*a*/);
  65 } arena_ops;
  66
  67 /*----- Global variables --------------------------------------------------*/
  68
  69 extern arena *arena_global;             /* Standard global arena */
  70 extern arena arena_stdlib;              /* Arena based on @malloc@/@free@ */
  71
  72 /*----- Functions provided ------------------------------------------------*/
  73
  74 /* --- @arena_fakerealloc@ --- *
  75  *
  76  * Arguments:   @arena *a@ = pointer to arena block
  77  *              @void *p@ = pointer to memory block to resize
  78  *              @size_t sz@ = size desired for the block
  79  *              @size_t osz@ = size of the old block
  80  *
  81  * Returns:     ---
  82  *
  83  * Use:         Standard fake @realloc@ function, for use if you don't
  84  *              support @realloc@ properly.
  85  */
  86
  87 extern void *arena_fakerealloc(arena */*a*/, void */*p*/,
  88                                size_t /*sz*/, size_t /*osz*/);
  89
  90 /* --- Useful macros --- */
  91
  92 #define A_ALLOC(a, sz) (((a)->ops->alloc)((a), (sz)))
  93 #define A_REALLOC(a, p, sz, osz) (((a)->ops->realloc)((a), (p), (sz), (osz)))
  94 #define A_FREE(a, p) (((a)->ops->free)((a), (p)))
  95
  96 /* --- Simple function equivalents --- */
  97
  98 extern void *a_alloc(arena */*a*/, size_t /*sz*/);
  99 extern void *a_realloc(arena */*a*/, void */*p*/,
 100                        size_t /*sz*/, size_t /*osz*/);
 101 extern void a_free(arena */*a*/, void */*p*/);
 102
 103 /*----- That's all, folks -------------------------------------------------*/
 104
 105 #ifdef __cplusplus
 106   }
 107 #endif
 108
 109 #endif