FreeBSD/Linux Kernel Cross Reference
sys/contrib/openzfs/module/lua/lmem.c

     /*
     ** $Id: lmem.c,v 1.84.1.1 2013/04/12 18:48:47 roberto Exp $
     ** Interface to Memory Manager
     ** See Copyright Notice in lua.h
     */
     
     
     #define lmem_c
     #define LUA_CORE
    
    #include <sys/lua/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;
    }
    
    
    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) {
        api_check(L, nsize > realosize,
                     "realloc cannot fail when shrinking a block");
        if (g->gcrunning) {
          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;
    }

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