Mercurial > vba-clojure

     1 /*

     2 ** $Id: lmem.c,v 1.70.1.1 2007/12/27 13:02:25 roberto Exp $

     3 ** Interface to Memory Manager

     4 ** See Copyright Notice in lua.h

     5 */

     6 

     7 

     8 #include <stddef.h>

     9 

    10 #define lmem_c

    11 #define LUA_CORE

    12 

    13 #include "lua.h"

    14 

    15 #include "ldebug.h"

    16 #include "ldo.h"

    17 #include "lmem.h"

    18 #include "lobject.h"

    19 #include "lstate.h"

    20 

    21 

    22 

    23 /*

    24 ** About the realloc function:

    25 ** void * frealloc (void *ud, void *ptr, size_t osize, size_t nsize);

    26 ** (`osize' is the old size, `nsize' is the new size)

    27 **

    28 ** Lua ensures that (ptr == NULL) iff (osize == 0).

    29 **

    30 ** * frealloc(ud, NULL, 0, x) creates a new block of size `x'

    31 **

    32 ** * frealloc(ud, p, x, 0) frees the block `p'

    33 ** (in this specific case, frealloc must return NULL).

    34 ** particularly, frealloc(ud, NULL, 0, 0) does nothing

    35 ** (which is equivalent to free(NULL) in ANSI C)

    36 **

    37 ** frealloc returns NULL if it cannot create or reallocate the area

    38 ** (any reallocation to an equal or smaller size cannot fail!)

    39 */

    40 

    41 

    42 

    43 #define MINSIZEARRAY	4

    44 

    45 

    46 void *luaM_growaux_ (lua_State *L, void *block, int *size, size_t size_elems,

    47                      int limit, const char *errormsg) {

    48   void *newblock;

    49   int newsize;

    50   if (*size >= limit/2) {  /* cannot double it? */

    51     if (*size >= limit)  /* cannot grow even a little? */

    52       luaG_runerror(L, errormsg);

    53     newsize = limit;  /* still have at least one free place */

    54   }

    55   else {

    56     newsize = (*size)*2;

    57     if (newsize < MINSIZEARRAY)

    58       newsize = MINSIZEARRAY;  /* minimum size */

    59   }

    60   newblock = luaM_reallocv(L, block, *size, newsize, size_elems);

    61   *size = newsize;  /* update only when everything else is OK */

    62   return newblock;

    63 }

    64 

    65 

    66 void *luaM_toobig (lua_State *L) {

    67   luaG_runerror(L, "memory allocation error: block too big");

    68   return NULL;  /* to avoid warnings */

    69 }

    70 

    71 

    72 

    73 /*

    74 ** generic allocation routine.

    75 */

    76 void *luaM_realloc_ (lua_State *L, void *block, size_t osize, size_t nsize) {

    77   global_State *g = G(L);

    78   lua_assert((osize == 0) == (block == NULL));

    79   block = (*g->frealloc)(g->ud, block, osize, nsize);

    80   if (block == NULL && nsize > 0)

    81     luaD_throw(L, LUA_ERRMEM);

    82   lua_assert((nsize == 0) == (block == NULL));

    83   g->totalbytes = (g->totalbytes - osize) + nsize;

    84   return block;

    85 }

    86
author	Robert McIntyre <rlm@mit.edu>
date	Sat, 01 Sep 2012 09:43:19 -0500
parents	27763b933818
children