ref: 74fcae28e6618ef19ba1b219b05e958475423a46
dir: /lua/src/lmem.c/
/*
** $Id: lmem.c,v 1.1 2006/12/23 01:55:12 rrt 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 "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)
**
** Lua ensures that (ptr == NULL) iff (osize == 0).
**
** * frealloc(ud, NULL, 0, x) creates a new block of size `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 *errormsg) {
void *newblock;
int newsize;
if (*size >= limit/2) { /* cannot double it? */
if (*size >= limit) /* cannot grow even a little? */
luaG_runerror(L, errormsg);
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;
}
void *luaM_toobig (lua_State *L) {
luaG_runerror(L, "memory allocation error: block too big");
return NULL; /* to avoid warnings */
}
/*
** generic allocation routine.
*/
void *luaM_realloc_ (lua_State *L, void *block, size_t osize, size_t nsize) {
global_State *g = G(L);
lua_assert((osize == 0) == (block == NULL));
block = (*g->frealloc)(g->ud, block, osize, nsize);
if (block == NULL && nsize > 0)
luaD_throw(L, LUA_ERRMEM);
lua_assert((nsize == 0) == (block == NULL));
g->totalbytes = (g->totalbytes - osize) + nsize;
return block;
}