/*
** $Id: ldo.h,v 2.29.1.1 2017/04/19 17:20:42 roberto Exp $
** Stack and Call structure of Lua
** See Copyright Notice in lua.h
*/

#ifndef ldo_h
#define ldo_h


#include "lobject.h"
#include "lstate.h"
#include "lzio.h"


/*
** Macro to check stack size and grow stack if needed.  Parameters
** 'pre'/'pos' allow the macro to preserve a pointer into the
** stack across reallocations, doing the work only when needed.
** 'condmovestack' is used in heavy tests to force a stack reallocation
** at every check.
*/
#define luaD_checkstackaux(L, n, pre, pos)  \
  if (L->stack_last - L->top <= (n)) \
    { pre; luaD_growstack(L, n); pos; } else { condmovestack(L,pre,pos); }

/* In general, 'pre'/'pos' are empty (nothing to save) */
#define luaD_checkstack(L, n)  luaD_checkstackaux(L,n,(void)0,(void)0)

// 这段代码是一个宏定义，用于简化计算 Lua 栈中某个元素相对于栈底的偏移量。宏定义 savestack(L, p) 旨在提供一个方便的方式来获取从当前 Lua 状态 L 的栈底 L->stack 到某个特定栈元素 p 的距离。
#define savestack(L, p)    ((char *)(p) - (char *)L->stack)
#define restorestack(L, n)  ((TValue *)((char *)L->stack + (n)))


/* type of protected functions, to be ran by 'runprotected' */
typedef void (*Pfunc)(lua_State *L, void *ud);

LUAI_FUNC int luaD_protectedparser(lua_State *L, ZIO *z, const char *name,
                                   const char *mode);

LUAI_FUNC void luaD_hook(lua_State *L, int event, int line);

LUAI_FUNC int luaD_precall(lua_State *L, StkId func, int nresults);

LUAI_FUNC void luaD_call(lua_State *L, StkId func, int nResults);

LUAI_FUNC void luaD_callnoyield(lua_State *L, StkId func, int nResults);

LUAI_FUNC int luaD_pcall(lua_State *L, Pfunc func, void *u,
                         ptrdiff_t oldtop, ptrdiff_t ef);

LUAI_FUNC int luaD_poscall(lua_State *L, CallInfo *ci, StkId firstResult,
                           int nres);

LUAI_FUNC void luaD_reallocstack(lua_State *L, int newsize);

LUAI_FUNC void luaD_growstack(lua_State *L, int n);

LUAI_FUNC void luaD_shrinkstack(lua_State *L);

LUAI_FUNC void luaD_inctop(lua_State *L);

LUAI_FUNC l_noret luaD_throw(lua_State *L, int errcode);

LUAI_FUNC int luaD_rawrunprotected(lua_State *L, Pfunc f, void *ud);

#endif