lua/lmem.c

/*
** $Id: lmem.c,v 1.68 2005/01/14 14:21:16 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 "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;
#if 0
  { /* auxiliar patch to monitor garbage collection */
    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("trace", "w");
      fprintf(f, "%lu %u %u %u %d\n", total, g->totalbytes, g->GCthreshold,
                                      g->estimate, g->gcstate);
    }
  }
#endif
  return block;
}