text: /*
  ** $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;
  }
  
  