lua/lmem.c
Roberto Ierusalimschy 9a9fe42deb wrong comment
2010-04-30 15:17:24 -03:00

125 lines
3.5 KiB
C

/*
** $Id: lmem.c,v 1.76 2010/04/29 17:33:17 roberto Exp roberto $
** 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;
}
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) {
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 && !gcstopped(g))
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 (!gcstopped(g)) {
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->totalbytes = (g->totalbytes - realosize) + nsize;
if (!gcstopped(g))
g->GCdebt += nsize; /* give some credit to garbage collector */
#if defined(TRACEMEM)
{ /* auxiliar patch to monitor garbage collection.
** To plot, gnuplot with following command:
** plot TRACEMEM using 1:2 with lines, TRACEMEM using 1:3 with lines
*/
static unsigned long total = 0; /* our "time" */
static lu_mem last = 0; /* last totalmem that generated an output */
static FILE *f = NULL; /* output file */
if (nsize <= osize) total += 1; /* "time" always grow */
else total += (nsize - osize);
if ((int)g->totalbytes - (int)last > 1000 ||
(int)g->totalbytes - (int)last < -1000) {
last = g->totalbytes;
if (f == NULL) f = fopen(TRACEMEM, "w");
fprintf(f, "%lu %u %u %d\n", total,
g->totalbytes,
g->GCthreshold < MAX_LUMEM ? g->GCthreshold : 0,
g->gcstate);
}
}
#endif
return newblock;
}