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

   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 /*----- Header files ------------------------------------------------------*/
  29
  30 #include <stdlib.h>
  31 #include <string.h>
  32
  33 #include "arena.h"
  34
  35 /*----- The standard arena ------------------------------------------------*/
  36
  37 static void *_alloc(arena *a, size_t sz) { return malloc(sz); }
  38 static void *_realloc(arena *a, void *p, size_t sz, size_t osz)
  39   { return realloc(p, sz); }
  40 static void _free(arena *a, void *p) { free(p); }
  41
  42 static arena_ops stdlib_ops = { _alloc, _realloc, _free, 0 };
  43 arena arena_stdlib = { &stdlib_ops };
  44
  45 /*----- Global variables --------------------------------------------------*/
  46
  47 arena *arena_global = &arena_stdlib;
  48
  49 /*----- Main code ---------------------------------------------------------*/
  50
  51 /* --- @arena_fakerealloc@ --- *
  52  *
  53  * Arguments:   @arena *a@ = pointer to arena block
  54  *              @void *p@ = pointer to memory block to resize
  55  *              @size_t sz@ = size desired for the block
  56  *              @size_t osz@ = size of the old block
  57  *
  58  * Returns:     ---
  59  *
  60  * Use:         Standard fake @realloc@ function, for use if you don't
  61  *              support @realloc@ properly.
  62  */
  63
  64 void *arena_fakerealloc(arena *a, void *p, size_t sz, size_t osz)
  65 {
  66   void *q = A_ALLOC(a, sz);
  67   if (!q)
  68     return (0);
  69   memcpy(q, p, sz > osz ? osz : sz);
  70   A_FREE(a, p);
  71   return (q);
  72 }
  73
  74 /* --- Function equivalents of the macros --- */
  75
  76 void *a_alloc(arena *a, size_t sz) { return (A_ALLOC(a, sz)); }
  77 void *a_realloc(arena *a, void *p, size_t sz, size_t osz)
  78 { return A_REALLOC(a, p, sz, osz); }
  79 void a_free(arena *a, void *p) { A_FREE(a, p); }
  80
  81 /*----- That's all, folks -------------------------------------------------*/