C++ setnilvalue函数代码示例

static void preinit_state (lua_State *L, global_State *g) {
    G(L) = g;
    L->stack = NULL;
    L->stacksize = 0;
    L->errorJmp = NULL;
    L->hook = NULL;
    L->hookmask = 0;
    L->basehookcount = 0;
    L->allowhook = 1;
    resethookcount(L);
    L->openupval = NULL;
    L->size_ci = 0;
    L->nCcalls = L->baseCcalls = 0;
    L->status = 0;
    L->base_ci = L->ci = NULL;
    L->savedpc = NULL;
    L->errfunc = 0;
    setnilvalue(gt(L));
}

static void traversestack (GCState *st, lua_State *L1) {
  StkId o, lim;
  CallInfo *ci;
  lua_State *L = st->L;
  (void)L;
  markobject(st, gt(L1));
  lim = L1->top;
  for (ci = L1->base_ci; ci <= L1->ci; ci++) {
    lua_assert(ci->top <= L1->stack_last);
    lua_assert(ci->state & (CI_C | CI_HASFRAME | CI_SAVEDPC));
    if (lim < ci->top)
      lim = ci->top;
  }
  for (o = L1->stack; o < L1->top; o++)
    markobject(st, o);
  for (; o <= lim; o++)
    setnilvalue(o);
  checkstacksizes(L1, lim);
}

static int addk (FuncState *fs, TValue *k, TValue *v) {
  lua_State *L = fs->L;
  TValue *idx = luaH_set(L, fs->h, k);
  Proto *f = fs->f;
  int oldsize = f->sizek;
  if (ttisnumber(idx)) {
    lua_assert(luaO_rawequalObj(&fs->f->k[cast_int(nvalue(idx))], v));
    return cast_int(nvalue(idx));
  }
  else {  /* constant not found; create a new entry */
    setnvalue(idx, cast_num(fs->nk));
    luaM_growvector(L, f->k, fs->nk, f->sizek, TValue,
                    MAXARG_Bx, "constant table overflow");
    while (oldsize < f->sizek) setnilvalue(&f->k[oldsize++]);
    setobj(L, &f->k[fs->nk], v);
    luaC_barrier(L, f, v);
    return fs->nk++;
  }
}

LUA_API void lua_pushcclosure (lua_State *L, lua_CFunction fn, int n) {
  Closure *cl;
  lua_lock(L);
  luaC_checkGC(L);
  api_checknelems(L, n);
  cl = luaF_newCclosure(L, n);
  cl->c.f = fn;
  L->top -= n;
  while (n--)
  {
    setobj2n(&cl->c.upvalue[n], L->top+n);
#if LUA_REFCOUNT
	setnilvalue(L->top+n);
#endif LUA_REFCOUNT
  }
  setclvalue(L->top, cl);
  api_incr_top(L);
  lua_unlock(L);
}

/*
** clear collected values from weaktables
*/
static void cleartablevalues (lua_State *L, GCObject *l) {
  while (l) {
    Table *h = gcotoh(l);
    int i = h->sizearray;
    lua_assert(h->marked & VALUEWEAK);
    while (i--) {
      TObject *o = &h->array[i];
      if (!valismarked(o))  /* value was collected? */
        setnilvalue(o);  /* remove value */
    }
    i = sizenode(h);
    while (i--) {
      Node *n = gnode(h, i);
      if (!valismarked(gval(n)))  /* value was collected? */
        removekey(L, n);  /* remove entry from table */
    }
    l = h->gclist;
  }
}

static int addk (FuncState *fs, TValue *k, TValue *v) {
  lua_State *L = fs->L;
  TValue *idx = luaH_set(L, fs->h, k);
#ifdef LUA_TINT
  /* Note: Integer-valued LUA_TNUMBER's are handled as in unpatched Lua (below)
  */
  if (ttype(idx)==LUA_TINT) {
    int i;
# ifdef LNUM_INT64
    lua_assert( (int)ivalue(idx) == ivalue(idx) );  /* make sure no data is lost in the casting */
# endif
    i= (int)ivalue(idx);
    lua_assert(luaO_rawequalObj(&fs->f->k[i], v));
    return i;
  }
  else if (ttype(idx)==LUA_TNUMBER) {
#else
  if (ttisnumber(idx)) {
#endif
    int i= cast_int(nvalue_fast(idx));
    lua_assert(luaO_rawequalObj(&fs->f->k[i], v));
    return i;
  }
  else {  /* constant not found; create a new entry */
    Proto *f = fs->f;
    int oldsize = f->sizek;
    setivalue(idx, fs->nk);
    luaM_growvector(L, f->k, fs->nk, f->sizek, TValue,
                    MAXARG_Bx, "constant table overflow");
    while (oldsize < f->sizek) setnilvalue(&f->k[oldsize++]);
    setobj(L, &f->k[fs->nk], v);
    luaC_barrier(L, f, v);
    return fs->nk++;
  }
}


int luaK_stringK (FuncState *fs, TString *s) {
  TValue o;
  setsvalue(fs->L, &o, s);
  return addk(fs, &o, &o);
}

static int nilK (FuncState *fs) {
  TValue k, v;
#if LUA_REFCOUNT
  lua_State *L = fs->L;
  int ret;
  setnilvalue2n(L, &v);
  luarc_newvalue(&k);
  /* cannot use nil as key; instead use table itself to represent nil */
  sethvalue(fs->L, &k, fs->h);
  ret = addk(fs, &k, &v);
  luarc_cleanvalue(&k);
  luarc_cleanvalue(&v);
  return ret;
#else
  setnilvalue(&v);
  /* cannot use nil as key; instead use table itself to represent nil */
  sethvalue(fs->L, &k, fs->h);
  return addk(fs, &k, &v);
#endif /* LUA_REFCOUNT */
}

static lu_mem traversestack (global_State *g, lua_State *th) {
	int n = 0;
	StkId o = th->stack;
	if (o == NULL)
	return 1;  /* stack not completely built yet */
	for (; o < th->top; o++)  /* mark live elements in the stack */
	markvalue(g, o);
	if (g->gcstate == GCSatomic) {  /* final traversal? */
	StkId lim = th->stack + th->stacksize;  /* real end of stack */
	for (; o < lim; o++)  /* clear not-marked stack slice */
		setnilvalue(o);
	}
	else {  /* count call infos to compute size */
	CallInfo *ci;
	for (ci = &th->base_ci; ci != th->ci; ci = ci->next)
		n++;
	}
	return sizeof(lua_State) + sizeof(TValue) * th->stacksize +
			sizeof(CallInfo) * n;
}

int php_deserialize( rabbit * r, rawbuffer * buf, TValue * tv )
{
	if(!buf || !tv) {
		return -1;
	}
	setnilvalue(tv);

	int c = decode_read_byte( buf );

	switch( c ) {
		case PHP_NULL:
	//		kLOG(r, 0,"php decode nil\n");
			return decode_null( r, buf, tv );

		case PHP_INT:
	//		kLOG(r, 0,"php decode int\n");
			return decode_int( r, buf, tv );

		case PHP_DOUBLE:
	//		kLOG(r, 0,"php decode double\n");
			return decode_double(r, buf, tv);

		case PHP_STRING:
	//		kLOG(r, 0,"php decode string\n");
			return decode_string(r, buf, tv);

		case PHP_ARRAY:
	//		kLOG(r, 0,"php decode array\n");
			return decode_array(r, buf, tv);

		case PHP_BOOL:
			return decode_bool(r, buf, tv);

		default:
			kLOG(r, 0, "php decode unknow:%c\n",c);
			break;
	}

	return -1;
}

void vm_OP_VARARG(lua_State *L, LClosure *cl, int a, int b) {
  TValue *base = L->base;
  TValue *ra = base + a;
  int j;
  CallInfo *ci = L->ci;
  int n = cast_int(ci->base - ci->func) - cl->p->numparams - 1;
  b -= 1;
  if (b == LUA_MULTRET) {
    Protect(luaD_checkstack(L, n));
    ra = base + a;  /* previous call may change the stack */
    b = n;
    L->top = ra + n;
  }
  for (j = 0; j < b; j++) {
    if (j < n) {
      setobjs2s(L, ra + j, ci->base - n + j);
    }
    else {
      setnilvalue(ra + j);
    }
  }
}

void luaV_settable (lua_State *L, const TValue *t, TValue *key, StkId val) {
  int loop;
  TValue temp;
  setnilvalue(L->top);
  L->top++;
  fixedstack(L);
  for (loop = 0; loop < MAXTAGLOOP; loop++) {
    const TValue *tm;
    if (ttistable(t) || ttisrotable(t)) {  /* `t' is a table? */
      void *h = ttistable(t) ? hvalue(t) : rvalue(t);
      TValue *oldval = ttistable(t) ? luaH_set(L, (Table*)h, key) : NULL; /* do a primitive set */
      if ((oldval && !ttisnil(oldval)) ||  /* result is no nil? */
          (tm = fasttm(L, ttistable(t) ? ((Table*)h)->metatable : (Table*)luaR_getmeta(h), TM_NEWINDEX)) == NULL) { /* or no TM? */
        if(oldval) {
          L->top--;
          unfixedstack(L);
          setobj2t(L, oldval, val);
          ((Table *)h)->flags = 0;
          luaC_barriert(L, (Table*)h, val);
        }
        return;
      }
      /* else will try the tag method */
    }
    else if (ttisnil(tm = luaT_gettmbyobj(L, t, TM_NEWINDEX)))
      luaG_typeerror(L, t, "index");
    if (ttisfunction(tm) || ttislightfunction(tm)) {
      L->top--;
      unfixedstack(L);
      callTM(L, tm, t, key, val);
      return;
    }
    /* else repeat with `tm' */
    setobj(L, &temp, tm);  /* avoid pointing inside table (may rehash) */
    t = &temp;
    setobj2s(L, L->top-1, t);  /* need to protect value from EGC. */
  }
  luaG_runerror(L, "loop in settable");
}

static lu_mem traversethread (global_State *g, lua_State *th) {
  StkId o = th->stack;
  if (o == NULL)
    return 1;  /* stack not completely built yet */
  lua_assert(g->gcstate == GCSinsideatomic ||
             th->openupval == NULL || isintwups(th));
  for (; o < th->top; o++)  /* mark live elements in the stack */
    markvalue(g, o);
  if (g->gcstate == GCSinsideatomic) {  /* final traversal? */
    StkId lim = th->stack + th->stacksize;  /* real end of stack */
    for (; o < lim; o++)  /* clear not-marked stack slice */
      setnilvalue(o);
    /* 'remarkupvals' may have removed thread from 'twups' list */ 
    if (!isintwups(th) && th->openupval != NULL) {
      th->twups = g->twups;  /* link it back to the list */
      g->twups = th;
    }
  }
  else if (g->gckind != KGC_EMERGENCY)
    luaD_shrinkstack(th); /* do not change stack in emergency cycle */
  return (sizeof(lua_State) + sizeof(TValue) * th->stacksize);
}

LUA_API int lua_getinfo (lua_State *L, const char *what, lua_Debug *ar)
{
    int status;
    Closure *f = NULL;
    CallInfo *ci = NULL;
    void *plight = NULL;
    lua_lock(L);
    if (*what == '>') {
        StkId func = L->top - 1;
        luai_apicheck(L, ttisfunction(func) || ttislightfunction(func));
        what++;  /* skip the '>' */
        if (ttisfunction(func))
            f = clvalue(func);
        else
            plight = fvalue(func);
        L->top--;  /* pop function */
    } else if (ar->i_ci != 0) { /* no tail call? */
        ci = L->base_ci + ar->i_ci;
        lua_assert(ttisfunction(ci->func) || ttislightfunction(ci->func));
        if (ttisfunction(ci->func))
            f = clvalue(ci->func);
        else
            plight = fvalue(ci->func);
    }
    status = auxgetinfo(L, what, ar, f, plight, ci);
    if (strchr(what, 'f')) {
        if (f != NULL)
            setclvalue(L, L->top, f)
            else if (plight != NULL)
                setfvalue(L->top, plight)
                else
                    setnilvalue(L->top);
        incr_top(L);
    }
    if (strchr(what, 'L'))
        collectvalidlines(L, f);
    lua_unlock(L);
    return status;
}

LUA_API int lua_setmetatable (lua_State *L, int objindex) {
  TObject *obj, *mt;
  int res = 1;
  lua_lock(L);
  api_checknelems(L, 1);
  obj = luaA_index(L, objindex);
  mt = (!ttisnil(L->top - 1)) ? L->top - 1 : defaultmeta(L);
  api_check(L, ttistable(mt));
  switch (ttype(obj)) {
    case LUA_TTABLE: {
#if LUA_REFCOUNT
      __AddRefDirect(hvalue(mt));
      __ReleaseDirect(L, hvalue(obj)->metatable);
#endif LUA_REFCOUNT
	  hvalue(obj)->metatable = hvalue(mt);  /* write barrier */
      break;
    }
    case LUA_TUSERDATA: {
#if LUA_REFCOUNT
      __AddRefDirect(hvalue(mt));
	  __ReleaseDirect(L, &uvalue(obj)->uv.metatable);
#endif LUA_REFCOUNT
      uvalue(obj)->uv.metatable = hvalue(mt);  /* write barrier */
      break;
    }
    default: {
      res = 0;  /* cannot set */
      break;
    }
  }
#if LUA_REFCOUNT
  setnilvalue(--L->top);
#else !LUA_REFCOUNT
  L->top--;
#endif LUA_REFCOUNT
  lua_unlock(L);
  return res;
}

/*
** open parts of the state that may cause memory-allocation errors.
** ('g->version' != NULL flags that the state was completely build)
*/
static void f_luaopen (lua_State *L, void *ud) {
  global_State *g = G(L);
  UNUSED(ud);
  stack_init(L, L);  /* init stack */
  init_registry(L, g);
#if LUA_FASTREF_SUPPORT
  {
    TValue n;

    sethvalue(L, &G(L)->l_refs, luaH_new(L));  /* refs */
    setivalue(&n, 0);
    luaH_setint(L, hvalue(&G(L)->l_refs), LUA_RIDX_FASTREF_FREELIST, &n);

    setnilvalue(&g->fastrefNilValue);
  }
#endif /* LUA_FASTREF_SUPPORT */
  luaS_init(L);
  luaT_init(L);
  luaX_init(L);
  g->gcrunning = 1;  /* allow gc */
  g->version = lua_version(NULL);
  luai_userstateopen(L);
}