lua/lmem.c
Roberto Ierusalimschy 063d4e4543 Lua 5.3.5 ported to git
This is the first commit for the branch Lua 5.3. All source files
were copied from the official distribution of 5.3.5 in the Lua site.
The test files are the same of 5.3.4. The manual came from the
previous RCS repository, revision 1.167.1.2.
2018-12-17 14:46:37 -02:00

101 lines
2.6 KiB
C

/*
** $Id: lmem.c,v 1.91.1.1 2017/04/19 17:20:42 roberto Exp $
** Interface to Memory Manager
** See Copyright Notice in lua.h
*/
#define lmem_c
#define LUA_CORE
#include "lprefix.h"
#include <stddef.h>
#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 ISO 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) {
lua_assert(nsize > realosize); /* cannot fail when shrinking a block */
if (g->version) { /* is state fully built? */
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;
}