/*

** $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;

}



