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

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