lmem.c
(5.0.3)
/*
** $Id: lmem.c,v 1.61 2002/12/04 17:38:31 roberto Exp $
** Interface to Memory Manager
** See Copyright Notice in lua.h
*/
#include <stdlib.h>
#define lmem_c
#include "lua.h"
#include "ldebug.h"
#include "ldo.h"
#include "lmem.h"
#include "lobject.h"
#include "lstate.h"
/*
** definition for realloc function. It must assure that l_realloc(NULL,
** 0, x) allocates a new block (ANSI C assures that). (`os' is the old
** block size; some allocators may use that.)
*/
#ifndef l_realloc
#define l_realloc(b,os,s) realloc(b,s)
#endif
/*
** definition for free function. (`os' is the old block size; some
** allocators may use that.)
*/
#ifndef l_free
#define l_free(b,os) free(b)
#endif
#define MINSIZEARRAY 4
void *luaM_growaux (lua_State *L, void *block, int *size, int size_elems,
int limit, const char *errormsg) {
void *newblock;
int newsize = (*size)*2;
if (newsize < MINSIZEARRAY)
newsize = MINSIZEARRAY; /* minimum size */
else if (*size >= limit/2) { /* cannot double it? */
if (*size < limit - MINSIZEARRAY) /* try something smaller... */
newsize = limit; /* still have at least MINSIZEARRAY free places */
else luaG_runerror(L, errormsg);
}
newblock = luaM_realloc(L, block,
cast(lu_mem, *size)*cast(lu_mem, size_elems),
cast(lu_mem, newsize)*cast(lu_mem, size_elems));
*size = newsize; /* update only when everything else is OK */
return newblock;
}
/*
** generic allocation routine.
*/
void *luaM_realloc (lua_State *L, void *block, lu_mem oldsize, lu_mem size) {
lua_assert((oldsize == 0) == (block == NULL));
if (size == 0) {
if (block != NULL) {
l_free(block, oldsize);
block = NULL;
}
else return NULL; /* avoid `nblocks' computations when oldsize==size==0 */
}
else if (size >= MAX_SIZET)
luaG_runerror(L, "memory allocation error: block too big");
else {
block = l_realloc(block, oldsize, size);
if (block == NULL) {
if (L)
luaD_throw(L, LUA_ERRMEM);
else return NULL; /* error before creating state! */
}
}
if (L) {
lua_assert(G(L) != NULL && G(L)->nblocks > 0);
G(L)->nblocks -= oldsize;
G(L)->nblocks += size;
}
return block;
}