/*

** $Id: lstate.h,v 1.109 2003/02/27 11:52:30 roberto Exp $

** Global State

** See Copyright Notice in lua.h

*/



#ifndef lstate_h

#define lstate_h



#include "lua.h"



#include "lobject.h"

#include "ltm.h"

#include "lzio.h"





/*

** macros for thread synchronization inside Lua core machine:

** all accesses to the global state and to global objects are synchronized.

** Because threads can read the stack of other threads

** (when running garbage collection),

** a thread must also synchronize any write-access to its own stack.

** Unsynchronized accesses are allowed only when reading its own stack,

** or when reading immutable fields from global objects

** (such as string values and udata values). 

*/

#ifndef lua_lock

#define lua_lock(L)	((void) 0)

#endif



#ifndef lua_unlock

#define lua_unlock(L)	((void) 0)

#endif





#ifndef lua_userstateopen

#define lua_userstateopen(l)

#endif







struct lua_longjmp;  /* defined in ldo.c */





/* default meta table (both for tables and udata) */

#define defaultmeta(L)	(&G(L)->_defaultmeta)



/* table of globals */

#define gt(L)	(&L->_gt)



/* registry */

#define registry(L)	(&G(L)->_registry)





/* extra stack space to handle TM calls and some other extras */

#define EXTRA_STACK   5





#define BASIC_CI_SIZE           8



#define BASIC_STACK_SIZE        (2*LUA_MINSTACK)







typedef struct stringtable {

  GCObject **hash;

  ls_nstr nuse;  /* number of elements */

  int size;

} stringtable;





/*

** informations about a call

*/

typedef struct CallInfo {

  StkId base;  /* base for called function */

  StkId	top;  /* top for this function */

  int state;  /* bit fields; see below */

  union {

    struct {  /* for Lua functions */

      const Instruction *savedpc;

      const Instruction **pc;  /* points to `pc' variable in `luaV_execute' */

      int tailcalls;  /* number of tail calls lost under this entry */

    } l;

    struct {  /* for C functions */

      int dummy;  /* just to avoid an empty struct */

    } c;

  } u;

} CallInfo;





/*

** bit fields for `CallInfo.state'

*/

#define CI_C		(1<<0)  /* 1 if function is a C function */

/* 1 if (Lua) function has an active `luaV_execute' running it */

#define CI_HASFRAME	(1<<1)

/* 1 if Lua function is calling another Lua function (and therefore its

   `pc' is being used by the other, and therefore CI_SAVEDPC is 1 too) */

#define CI_CALLING	(1<<2)

#define CI_SAVEDPC	(1<<3)  /* 1 if `savedpc' is updated */

#define CI_YIELD	(1<<4)  /* 1 if thread is suspended */





#define ci_func(ci)	(clvalue((ci)->base - 1))





/*

** `global state', shared by all threads of this state

*/

typedef struct global_State {

  stringtable strt;  /* hash table for strings */

  GCObject *rootgc;  /* list of (almost) all collectable objects */

  GCObject *rootudata;   /* (separated) list of all userdata */

  GCObject *tmudata;  /* list of userdata to be GC */

  Mbuffer buff;  /* temporary buffer for string concatentation */

  lu_mem GCthreshold;

  lu_mem nblocks;  /* number of `bytes' currently allocated */

  lua_CFunction panic;  /* to be called in unprotected errors */

  TObject _registry;

  TObject _defaultmeta;

  struct lua_State *mainthread;

  Node dummynode[1];  /* common node array for all empty tables */

  TString *tmname[TM_N];  /* array with tag-method names */

} global_State;





/*

** `per thread' state

*/

struct lua_State {

  CommonHeader;

  StkId top;  /* first free slot in the stack */

  StkId base;  /* base of current function */

  global_State *l_G;

  CallInfo *ci;  /* call info for current function */

  StkId stack_last;  /* last free slot in the stack */

  StkId stack;  /* stack base */

  int stacksize;

  CallInfo *end_ci;  /* points after end of ci array*/

  CallInfo *base_ci;  /* array of CallInfo's */

  unsigned short size_ci;  /* size of array `base_ci' */

  unsigned short nCcalls;  /* number of nested C calls */

  lu_byte hookmask;

  lu_byte allowhook;

  lu_byte hookinit;

  int basehookcount;

  int hookcount;

  lua_Hook hook;

  TObject _gt;  /* table of globals */

  GCObject *openupval;  /* list of open upvalues in this stack */

  GCObject *gclist;

  struct lua_longjmp *errorJmp;  /* current error recover point */

  ptrdiff_t errfunc;  /* current error handling function (stack index) */

};





#define G(L)	(L->l_G)





/*

** Union of all collectable objects

*/

union GCObject {

  GCheader gch;

  union TString ts;

  union Udata u;

  union Closure cl;

  struct Table h;

  struct Proto p;

  struct UpVal uv;

  struct lua_State th;  /* thread */

};





/* macros to convert a GCObject into a specific value */

#define gcotots(o)	check_exp((o)->gch.tt == LUA_TSTRING, &((o)->ts))

#define gcotou(o)	check_exp((o)->gch.tt == LUA_TUSERDATA, &((o)->u))

#define gcotocl(o)	check_exp((o)->gch.tt == LUA_TFUNCTION, &((o)->cl))

#define gcotoh(o)	check_exp((o)->gch.tt == LUA_TTABLE, &((o)->h))

#define gcotop(o)	check_exp((o)->gch.tt == LUA_TPROTO, &((o)->p))

#define gcotouv(o)	check_exp((o)->gch.tt == LUA_TUPVAL, &((o)->uv))

#define ngcotouv(o) \

	check_exp((o) == NULL || (o)->gch.tt == LUA_TUPVAL, &((o)->uv))

#define gcototh(o)	check_exp((o)->gch.tt == LUA_TTHREAD, &((o)->th))



/* macro to convert any value into a GCObject */

#define valtogco(v)	(cast(GCObject *, (v)))





lua_State *luaE_newthread (lua_State *L);

void luaE_freethread (lua_State *L, lua_State *L1);



#endif



