external/mit/lua/dist/src/lmem.c

   1 /*      $NetBSD: lmem.c,v 1.4 2015/10/08 13:21:00 mbalmer Exp $ */
   2
   3 /*
   4 ** Id: lmem.c,v 1.91 2015/03/06 19:45:54 roberto Exp
   5 ** Interface to Memory Manager
   6 ** See Copyright Notice in lua.h
   7 */
   8
   9 #define lmem_c
  10 #define LUA_CORE
  11
  12 #include "lprefix.h"
  13
  14
  15 #ifndef _KERNEL
  16 #include <stddef.h>
  17 #endif
  18
  19 #include "lua.h"
  20
  21 #include "ldebug.h"
  22 #include "ldo.h"
  23 #include "lgc.h"
  24 #include "lmem.h"
  25 #include "lobject.h"
  26 #include "lstate.h"
  27
  28
  29
  30 /*
  31 ** About the realloc function:
  32 ** void * frealloc (void *ud, void *ptr, size_t osize, size_t nsize);
  33 ** ('osize' is the old size, 'nsize' is the new size)
  34 **
  35 ** * frealloc(ud, NULL, x, s) creates a new block of size 's' (no
  36 ** matter 'x').
  37 **
  38 ** * frealloc(ud, p, x, 0) frees the block 'p'
  39 ** (in this specific case, frealloc must return NULL);
  40 ** particularly, frealloc(ud, NULL, 0, 0) does nothing
  41 ** (which is equivalent to free(NULL) in ISO C)
  42 **
  43 ** frealloc returns NULL if it cannot create or reallocate the area
  44 ** (any reallocation to an equal or smaller size cannot fail!)
  45 */
  46
  47
  48
  49 #define MINSIZEARRAY    4
  50
  51
  52 void *luaM_growaux_ (lua_State *L, void *block, int *size, size_t size_elems,
  53                      int limit, const char *what) {
  54   void *newblock;
  55   int newsize;
  56   if (*size >= limit/2) {  /* cannot double it? */
  57     if (*size >= limit)  /* cannot grow even a little? */
  58       luaG_runerror(L, "too many %s (limit is %d)", what, limit);
  59     newsize = limit;  /* still have at least one free place */
  60   }
  61   else {
  62     newsize = (*size)*2;
  63     if (newsize < MINSIZEARRAY)
  64       newsize = MINSIZEARRAY;  /* minimum size */
  65   }
  66   newblock = luaM_reallocv(L, block, *size, newsize, size_elems);
  67   *size = newsize;  /* update only when everything else is OK */
  68   return newblock;
  69 }
  70
  71
  72 l_noret luaM_toobig (lua_State *L) {
  73   luaG_runerror(L, "memory allocation error: block too big");
  74 }
  75
  76
  77
  78 /*
  79 ** generic allocation routine.
  80 */
  81 void *luaM_realloc_ (lua_State *L, void *block, size_t osize, size_t nsize) {
  82   void *newblock;
  83   global_State *g = G(L);
  84   size_t realosize = (block) ? osize : 0;
  85   lua_assert((realosize == 0) == (block == NULL));
  86 #if defined(HARDMEMTESTS)
  87   if (nsize > realosize && g->gcrunning)
  88     luaC_fullgc(L, 1);  /* force a GC whenever possible */
  89 #endif
  90   newblock = (*g->frealloc)(g->ud, block, osize, nsize);
  91   if (newblock == NULL && nsize > 0) {
  92     lua_assert(nsize > realosize);  /* cannot fail when shrinking a block */
  93     if (g->version) {  /* is state fully built? */
  94       luaC_fullgc(L, 1);  /* try to free some memory... */
  95       newblock = (*g->frealloc)(g->ud, block, osize, nsize);  /* try again */
  96     }
  97     if (newblock == NULL)
  98       luaD_throw(L, LUA_ERRMEM);
  99   }
 100   lua_assert((nsize == 0) == (newblock == NULL));
 101   g->GCdebt = (g->GCdebt + nsize) - realosize;
 102   return newblock;
 103 }
 104