/*

** $Id: lmem.c,v 1.84.1.1 2013/04/12 18:48:47 roberto Exp $

** Interface to Memory Manager

** See Copyright Notice in lua.h

*/

#include <stddef.h>

#define lmem_c

#define LUA_CORE

#include "lua.h"

#include "ldebug.h"

#include "ldo.h"

#include "lgc.h"

#include "lmem.h"

#include "lobject.h"

#include "lstate.h"

/*

** About the realloc function:

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

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

**

** * frealloc(ud, NULL, x, s) creates a new block of size `s' (no

** matter 'x').

**

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

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

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

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

**

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

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

*/

#define MINSIZEARRAY 4

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

int limit, const char *what) {

void *newblock;

int newsize;

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

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

luaG_runerror(L, "too many %s (limit is %d)", what, limit);

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

}

else {

newsize = (*size)*2;

if (newsize < MINSIZEARRAY)

newsize = MINSIZEARRAY; /* minimum size */

}

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

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

return newblock;

}

l_noret luaM_toobig (lua_State *L) {

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

}

/*

** generic allocation routine.

*/

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

void *newblock;

global_State *g = G(L);

size_t realosize = (block) ? osize : 0;

lua_assert((realosize == 0) == (block == NULL));

#if defined(HARDMEMTESTS)

if (nsize > realosize && g->gcrunning)

luaC_fullgc(L, 1); /* force a GC whenever possible */

#endif

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

if (newblock == NULL && nsize > 0) {

api_check(L, nsize > realosize,

"realloc cannot fail when shrinking a block");

if (g->gcrunning) {

luaC_fullgc(L, 1); /* try to free some memory... */

newblock = (*g->frealloc)(g->ud, block, osize, nsize); /* try again */

}

if (newblock == NULL)

luaD_throw(L, LUA_ERRMEM);

}

lua_assert((nsize == 0) == (newblock == NULL));

g->GCdebt = (g->GCdebt + nsize) - realosize;

return newblock;

}