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/*
** $Id: lstate.h $
** Global State
** See Copyright Notice in lua.h
*/

#ifndef lstate_h
#define lstate_h

#include "lua.h"


/* Some header files included here need this definition */
typedef struct CallInfo CallInfo;


#include "lobject.h"
#include "ltm.h"
#include "lzio.h"


/*
** Some notes about garbage-collected objects: All objects in Lua must
** be kept somehow accessible until being freed, so all objects always
** belong to one (and only one) of these lists, using field 'next' of
** the 'CommonHeader' for the link:
**
** 'allgc': all objects not marked for finalization;
** 'finobj': all objects marked for finalization;
** 'tobefnz': all objects ready to be finalized;
** 'fixedgc': all objects that are not to be collected (currently
** only small strings, such as reserved words).
**
** For the generational collector, some of these lists have marks for
** generations. Each mark points to the first element in the list for
** that particular generation; that generation goes until the next mark.
**
** 'allgc' -> 'survival': new objects;
** 'survival' -> 'old': objects that survived one collection;
** 'old1' -> 'reallyold': objects that became old in last collection;
** 'reallyold' -> NULL: objects old for more than one cycle.
**
** 'finobj' -> 'finobjsur': new objects marked for finalization;
** 'finobjsur' -> 'finobjold1': survived   """";
** 'finobjold1' -> 'finobjrold': just old  """";
** 'finobjrold' -> NULL: really old       """".
**
** All lists can contain elements older than their main ages, due
** to 'luaC_checkfinalizer' and 'udata2finalize', which move
** objects between the normal lists and the "marked for finalization"
** lists. Moreover, barriers can age young objects in young lists as
** OLD0, which then become OLD1. However, a list never contains
** elements younger than their main ages.
**
** The generational collector also uses a pointer 'firstold1', which
** points to the first OLD1 object in the list. It is used to optimize
** 'markold'. (Potentially OLD1 objects can be anywhere between 'allgc'
** and 'reallyold', but often the list has no OLD1 objects or they are
** after 'old1'.) Note the difference between it and 'old1':
** 'firstold1': no OLD1 objects before this point; there can be all
**   ages after it.
** 'old1': no objects younger than OLD1 after this point.
*/

/*
** Moreover, there is another set of lists that control gray objects.
** These lists are linked by fields 'gclist'. (All objects that
** can become gray have such a field. The field is not the same
** in all objects, but it always has this name.)  Any gray object
** must belong to one of these lists, and all objects in these lists
** must be gray (with two exceptions explained below):
**
** 'gray': regular gray objects, still waiting to be visited.
** 'grayagain': objects that must be revisited at the atomic phase.
**   That includes
**   - black objects got in a write barrier;
**   - all kinds of weak tables during propagation phase;
**   - all threads.
** 'weak': tables with weak values to be cleared;
** 'ephemeron': ephemeron tables with white->white entries;
** 'allweak': tables with weak keys and/or weak values to be cleared.
**
** The exceptions to that "gray rule" are:
** - TOUCHED2 objects in generational mode stay in a gray list (because
** they must be visited again at the end of the cycle), but they are
** marked black because assignments to them must activate barriers (to
** move them back to TOUCHED1).
** - Open upvales are kept gray to avoid barriers, but they stay out
** of gray lists. (They don't even have a 'gclist' field.)
*/



/*
** About 'nCcalls':  This count has two parts: the lower 16 bits counts
** the number of recursive invocations in the C stack; the higher
** 16 bits counts the number of non-yieldable calls in the stack.
** (They are together so that we can change and save both with one
** instruction.)
*/


/* true if this thread does not have non-yieldable calls in the stack */
#define yieldable(L)		(((L)->nCcalls & 0xffff0000) == 0)

/* real number of C calls */
#define getCcalls(L)	((L)->nCcalls & 0xffff)


/* Increment the number of non-yieldable calls */
#define incnny(L)	((L)->nCcalls += 0x10000)

/* Decrement the number of non-yieldable calls */
#define decnny(L)	((L)->nCcalls -= 0x10000)

/* Non-yieldable call increment */
#define nyci	(0x10000 | 1)




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


/*
** Atomic type (relative to signals) to better ensure that 'lua_sethook'
** is thread safe
*/
#if !defined(l_signalT)
#include <signal.h>
#define l_signalT	sig_atomic_t
#endif


/*
** Extra stack space to handle TM calls and some other extras. This
** space is not included in 'stack_last'. It is used only to avoid stack
** checks, either because the element will be promptly popped or because
** there will be a stack check soon after the push. Function frames
** never use this extra space, so it does not need to be kept clean.
*/
#define EXTRA_STACK   5


#define BASIC_STACK_SIZE        (2*LUA_MINSTACK)

#define stacksize(th)	cast_int((th)->stack_last.p - (th)->stack.p)


/* kinds of Garbage Collection */
#define KGC_INC		0	/* incremental gc */
#define KGC_GEN		1	/* generational gc */


typedef struct stringtable {
  TString **hash;
  int nuse;  /* number of elements */
  int size;
} stringtable;


/*
** Information about a call.
** About union 'u':
** - field 'l' is used only for Lua functions;
** - field 'c' is used only for C functions.
** About union 'u2':
** - field 'funcidx' is used only by C functions while doing a
** protected call;
** - field 'nyield' is used only while a function is "doing" an
** yield (from the yield until the next resume);
** - field 'nres' is used only while closing tbc variables when
** returning from a function;
** - field 'transferinfo' is used only during call/returnhooks,
** before the function starts or after it ends.
*/
struct CallInfo {
  StkIdRel func;  /* function index in the stack */
  StkIdRel	top;  /* top for this function */
  struct CallInfo *previous, *next;  /* dynamic call link */
  union {
    struct {  /* only for Lua functions */
      const Instruction *savedpc;
      volatile l_signalT trap;  /* function is tracing lines/counts */
      int nextraargs;  /* # of extra arguments in vararg functions */
    } l;
    struct {  /* only for C functions */
      lua_KFunction k;  /* continuation in case of yields */
      ptrdiff_t old_errfunc;
      lua_KContext ctx;  /* context info. in case of yields */
    } c;
  } u;
  union {
    int funcidx;  /* called-function index */
    int nyield;  /* number of values yielded */
    int nres;  /* number of values returned */
    struct {  /* info about transferred values (for call/return hooks) */
      unsigned short ftransfer;  /* offset of first value transferred */
      unsigned short ntransfer;  /* number of values transferred */
    } transferinfo;
  } u2;
  short nresults;  /* expected number of results from this function */
  unsigned short callstatus;
};


/*
** Bits in CallInfo status
*/
#define CIST_OAH	(1<<0)	/* original value of 'allowhook' */
#define CIST_C		(1<<1)	/* call is running a C function */
#define CIST_FRESH	(1<<2)	/* call is on a fresh "luaV_execute" frame */
#define CIST_HOOKED	(1<<3)	/* call is running a debug hook */
#define CIST_YPCALL	(1<<4)	/* doing a yieldable protected call */
#define CIST_TAIL	(1<<5)	/* call was tail called */
#define CIST_HOOKYIELD	(1<<6)	/* last hook called yielded */
#define CIST_FIN	(1<<7)	/* function "called" a finalizer */
#define CIST_TRAN	(1<<8)	/* 'ci' has transfer information */
#define CIST_CLSRET	(1<<9)  /* function is closing tbc variables */
/* Bits 10-12 are used for CIST_RECST (see below) */
#define CIST_RECST	10
#if defined(LUA_COMPAT_LT_LE)
#define CIST_LEQ	(1<<13)  /* using __lt for __le */
#endif


/*
** Field CIST_RECST stores the "recover status", used to keep the error
** status while closing to-be-closed variables in coroutines, so that
** Lua can correctly resume after an yield from a __close method called
** because of an error.  (Three bits are enough for error status.)
*/
#define getcistrecst(ci)     (((ci)->callstatus >> CIST_RECST) & 7)
#define setcistrecst(ci,st)  \
  check_exp(((st) & 7) == (st),   /* status must fit in three bits */  \
            ((ci)->callstatus = ((ci)->callstatus & ~(7 << CIST_RECST))  \
                                                  | ((st) << CIST_RECST)))


/* active function is a Lua function */
#define isLua(ci)	(!((ci)->callstatus & CIST_C))

/* call is running Lua code (not a hook) */
#define isLuacode(ci)	(!((ci)->callstatus & (CIST_C | CIST_HOOKED)))

/* assume that CIST_OAH has offset 0 and that 'v' is strictly 0/1 */
#define setoah(st,v)	((st) = ((st) & ~CIST_OAH) | (v))
#define getoah(st)	((st) & CIST_OAH)


/*
** 'global state', shared by all threads of this state
*/
typedef struct global_State {
  lua_Alloc frealloc;  /* function to reallocate memory */
  void *ud;         /* auxiliary data to 'frealloc' */
  l_mem totalbytes;  /* number of bytes currently allocated - GCdebt */
  l_mem GCdebt;  /* bytes allocated not yet compensated by the collector */
  lu_mem GCestimate;  /* an estimate of the non-garbage memory in use */
  lu_mem lastatomic;  /* see function 'genstep' in file 'lgc.c' */
  stringtable strt;  /* hash table for strings */
  TValue l_registry;
  TValue nilvalue;  /* a nil value */
  unsigned int seed;  /* randomized seed for hashes */
  lu_byte currentwhite;
  lu_byte gcstate;  /* state of garbage collector */
  lu_byte gckind;  /* kind of GC running */
  lu_byte gcstopem;  /* stops emergency collections */
  lu_byte genminormul;  /* control for minor generational collections */
  lu_byte genmajormul;  /* control for major generational collections */
  lu_byte gcstp;  /* control whether GC is running */
  lu_byte gcemergency;  /* true if this is an emergency collection */
  lu_byte gcpause;  /* size of pause between successive GCs */
  lu_byte gcstepmul;  /* GC "speed" */
  lu_byte gcstepsize;  /* (log2 of) GC granularity */
  GCObject *allgc;  /* list of all collectable objects */
  GCObject **sweepgc;  /* current position of sweep in list */
  GCObject *finobj;  /* list of collectable objects with finalizers */
  GCObject *gray;  /* list of gray objects */
  GCObject *grayagain;  /* list of objects to be traversed atomically */
  GCObject *weak;  /* list of tables with weak values */
  GCObject *ephemeron;  /* list of ephemeron tables (weak keys) */
  GCObject *allweak;  /* list of all-weak tables */
  GCObject *tobefnz;  /* list of userdata to be GC */
  GCObject *fixedgc;  /* list of objects not to be collected */
  /* fields for generational collector */
  GCObject *survival;  /* start of objects that survived one GC cycle */
  GCObject *old1;  /* start of old1 objects */
  GCObject *reallyold;  /* objects more than one cycle old ("really old") */
  GCObject *firstold1;  /* first OLD1 object in the list (if any) */
  GCObject *finobjsur;  /* list of survival objects with finalizers */
  GCObject *finobjold1;  /* list of old1 objects with finalizers */
  GCObject *finobjrold;  /* list of really old objects with finalizers */
  struct lua_State *twups;  /* list of threads with open upvalues */
  lua_CFunction panic;  /* to be called in unprotected errors */
  struct lua_State *mainthread;
  TString *memerrmsg;  /* message for memory-allocation errors */
  TString *tmname[TM_N];  /* array with tag-method names */
  struct Table *mt[LUA_NUMTYPES];  /* metatables for basic types */
  TString *strcache[STRCACHE_N][STRCACHE_M];  /* cache for strings in API */
  lua_WarnFunction warnf;  /* warning function */
  void *ud_warn;         /* auxiliary data to 'warnf' */
} global_State;


/*
** 'per thread' state
*/
struct lua_State {
  CommonHeader;
  lu_byte status;
  lu_byte allowhook;
  unsigned short nci;  /* number of items in 'ci' list */
  StkIdRel top;  /* first free slot in the stack */
  global_State *l_G;
  CallInfo *ci;  /* call info for current function */
  StkIdRel stack_last;  /* end of stack (last element + 1) */
  StkIdRel stack;  /* stack base */
  UpVal *openupval;  /* list of open upvalues in this stack */
  StkIdRel tbclist;  /* list of to-be-closed variables */
  GCObject *gclist;
  struct lua_State *twups;  /* list of threads with open upvalues */
  struct lua_longjmp *errorJmp;  /* current error recover point */
  CallInfo base_ci;  /* CallInfo for first level (C calling Lua) */
  volatile lua_Hook hook;
  ptrdiff_t errfunc;  /* current error handling function (stack index) */
  l_uint32 nCcalls;  /* number of nested (non-yieldable | C)  calls */
  int oldpc;  /* last pc traced */
  int basehookcount;
  int hookcount;
  volatile l_signalT hookmask;
};


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

/*
** 'g->nilvalue' being a nil value flags that the state was completely
** build.
*/
#define completestate(g)	ttisnil(&g->nilvalue)


/*
** Union of all collectable objects (only for conversions)
** ISO C99, 6.5.2.3 p.5:
** "if a union contains several structures that share a common initial
** sequence [...], and if the union object currently contains one
** of these structures, it is permitted to inspect the common initial
** part of any of them anywhere that a declaration of the complete type
** of the union is visible."
*/
union GCUnion {
  GCObject gc;  /* common header */
  struct TString ts;
  struct Udata u;
  union Closure cl;
  struct Table h;
  struct Proto p;
  struct lua_State th;  /* thread */
  struct UpVal upv;
};


/*
** ISO C99, 6.7.2.1 p.14:
** "A pointer to a union object, suitably converted, points to each of
** its members [...], and vice versa."
*/
#define cast_u(o)	cast(union GCUnion *, (o))

/* macros to convert a GCObject into a specific value */
#define gco2ts(o)  \
	check_exp(novariant((o)->tt) == LUA_TSTRING, &((cast_u(o))->ts))
#define gco2u(o)  check_exp((o)->tt == LUA_VUSERDATA, &((cast_u(o))->u))
#define gco2lcl(o)  check_exp((o)->tt == LUA_VLCL, &((cast_u(o))->cl.l))
#define gco2ccl(o)  check_exp((o)->tt == LUA_VCCL, &((cast_u(o))->cl.c))
#define gco2cl(o)  \
	check_exp(novariant((o)->tt) == LUA_TFUNCTION, &((cast_u(o))->cl))
#define gco2t(o)  check_exp((o)->tt == LUA_VTABLE, &((cast_u(o))->h))
#define gco2p(o)  check_exp((o)->tt == LUA_VPROTO, &((cast_u(o))->p))
#define gco2th(o)  check_exp((o)->tt == LUA_VTHREAD, &((cast_u(o))->th))
#define gco2upv(o)	check_exp((o)->tt == LUA_VUPVAL, &((cast_u(o))->upv))


/*
** macro to convert a Lua object into a GCObject
** (The access to 'tt' tries to ensure that 'v' is actually a Lua object.)
*/
#define obj2gco(v)	check_exp((v)->tt >= LUA_TSTRING, &(cast_u(v)->gc))


/* actual number of total bytes allocated */
#define gettotalbytes(g)	cast(lu_mem, (g)->totalbytes + (g)->GCdebt)

LUAI_FUNC void luaE_setdebt (global_State *g, l_mem debt);
LUAI_FUNC void luaE_freethread (lua_State *L, lua_State *L1);
LUAI_FUNC CallInfo *luaE_extendCI (lua_State *L);
LUAI_FUNC void luaE_shrinkCI (lua_State *L);
LUAI_FUNC void luaE_checkcstack (lua_State *L);
LUAI_FUNC void luaE_incCstack (lua_State *L);
LUAI_FUNC void luaE_warning (lua_State *L, const char *msg, int tocont);
LUAI_FUNC void luaE_warnerror (lua_State *L, const char *where);
LUAI_FUNC int luaE_resetthread (lua_State *L, int status);


#endif

	/*
	** $Id: lstate.h $
	** Global State
	** See Copyright Notice in lua.h
	*/

	#ifndef lstate_h
	#define lstate_h

	#include "lua.h"


	/* Some header files included here need this definition */
	typedef struct CallInfo CallInfo;


	#include "lobject.h"
	#include "ltm.h"
	#include "lzio.h"


	/*
	** Some notes about garbage-collected objects: All objects in Lua must
	** be kept somehow accessible until being freed, so all objects always
	** belong to one (and only one) of these lists, using field 'next' of
	** the 'CommonHeader' for the link:
	**
	** 'allgc': all objects not marked for finalization;
	** 'finobj': all objects marked for finalization;
	** 'tobefnz': all objects ready to be finalized;
	** 'fixedgc': all objects that are not to be collected (currently
	** only small strings, such as reserved words).
	**
	** For the generational collector, some of these lists have marks for
	** generations. Each mark points to the first element in the list for
	** that particular generation; that generation goes until the next mark.
	**
	** 'allgc' -> 'survival': new objects;
	** 'survival' -> 'old': objects that survived one collection;
	** 'old1' -> 'reallyold': objects that became old in last collection;
	** 'reallyold' -> NULL: objects old for more than one cycle.
	**
	** 'finobj' -> 'finobjsur': new objects marked for finalization;
	** 'finobjsur' -> 'finobjold1': survived """";
	** 'finobjold1' -> 'finobjrold': just old """";
	** 'finobjrold' -> NULL: really old """".
	**
	** All lists can contain elements older than their main ages, due
	** to 'luaC_checkfinalizer' and 'udata2finalize', which move
	** objects between the normal lists and the "marked for finalization"
	** lists. Moreover, barriers can age young objects in young lists as
	** OLD0, which then become OLD1. However, a list never contains
	** elements younger than their main ages.
	**
	** The generational collector also uses a pointer 'firstold1', which
	** points to the first OLD1 object in the list. It is used to optimize
	** 'markold'. (Potentially OLD1 objects can be anywhere between 'allgc'
	** and 'reallyold', but often the list has no OLD1 objects or they are
	** after 'old1'.) Note the difference between it and 'old1':
	** 'firstold1': no OLD1 objects before this point; there can be all
	** ages after it.
	** 'old1': no objects younger than OLD1 after this point.
	*/

	/*
	** Moreover, there is another set of lists that control gray objects.
	** These lists are linked by fields 'gclist'. (All objects that
	** can become gray have such a field. The field is not the same
	** in all objects, but it always has this name.) Any gray object
	** must belong to one of these lists, and all objects in these lists
	** must be gray (with two exceptions explained below):
	**
	** 'gray': regular gray objects, still waiting to be visited.
	** 'grayagain': objects that must be revisited at the atomic phase.
	** That includes
	** - black objects got in a write barrier;
	** - all kinds of weak tables during propagation phase;
	** - all threads.
	** 'weak': tables with weak values to be cleared;
	** 'ephemeron': ephemeron tables with white->white entries;
	** 'allweak': tables with weak keys and/or weak values to be cleared.
	**
	** The exceptions to that "gray rule" are:
	** - TOUCHED2 objects in generational mode stay in a gray list (because
	** they must be visited again at the end of the cycle), but they are
	** marked black because assignments to them must activate barriers (to
	** move them back to TOUCHED1).
	** - Open upvales are kept gray to avoid barriers, but they stay out
	** of gray lists. (They don't even have a 'gclist' field.)
	*/



	/*
	** About 'nCcalls': This count has two parts: the lower 16 bits counts
	** the number of recursive invocations in the C stack; the higher
	** 16 bits counts the number of non-yieldable calls in the stack.
	** (They are together so that we can change and save both with one
	** instruction.)
	*/


	/* true if this thread does not have non-yieldable calls in the stack */
	#define yieldable(L) (((L)->nCcalls & 0xffff0000) == 0)

	/* real number of C calls */
	#define getCcalls(L) ((L)->nCcalls & 0xffff)


	/* Increment the number of non-yieldable calls */
	#define incnny(L) ((L)->nCcalls += 0x10000)

	/* Decrement the number of non-yieldable calls */
	#define decnny(L) ((L)->nCcalls -= 0x10000)

	/* Non-yieldable call increment */
	#define nyci (0x10000 \| 1)




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


	/*
	** Atomic type (relative to signals) to better ensure that 'lua_sethook'
	** is thread safe
	*/
	#if !defined(l_signalT)
	#include <signal.h>
	#define l_signalT sig_atomic_t
	#endif


	/*
	** Extra stack space to handle TM calls and some other extras. This
	** space is not included in 'stack_last'. It is used only to avoid stack
	** checks, either because the element will be promptly popped or because
	** there will be a stack check soon after the push. Function frames
	** never use this extra space, so it does not need to be kept clean.
	*/
	#define EXTRA_STACK 5


	#define BASIC_STACK_SIZE (2*LUA_MINSTACK)

	#define stacksize(th) cast_int((th)->stack_last.p - (th)->stack.p)


	/* kinds of Garbage Collection */
	#define KGC_INC 0 /* incremental gc */
	#define KGC_GEN 1 /* generational gc */


	typedef struct stringtable {
	TString **hash;
	int nuse; /* number of elements */
	int size;
	} stringtable;


	/*
	** Information about a call.
	** About union 'u':
	** - field 'l' is used only for Lua functions;
	** - field 'c' is used only for C functions.
	** About union 'u2':
	** - field 'funcidx' is used only by C functions while doing a
	** protected call;
	** - field 'nyield' is used only while a function is "doing" an
	** yield (from the yield until the next resume);
	** - field 'nres' is used only while closing tbc variables when
	** returning from a function;
	** - field 'transferinfo' is used only during call/returnhooks,
	** before the function starts or after it ends.
	*/
	struct CallInfo {
	StkIdRel func; /* function index in the stack */
	StkIdRel top; /* top for this function */
	struct CallInfo previous, next; /* dynamic call link */
	union {
	struct { /* only for Lua functions */
	const Instruction *savedpc;
	volatile l_signalT trap; /* function is tracing lines/counts */
	int nextraargs; /* # of extra arguments in vararg functions */
	} l;
	struct { /* only for C functions */
	lua_KFunction k; /* continuation in case of yields */
	ptrdiff_t old_errfunc;
	lua_KContext ctx; /* context info. in case of yields */
	} c;
	} u;
	union {
	int funcidx; /* called-function index */
	int nyield; /* number of values yielded */
	int nres; /* number of values returned */
	struct { /* info about transferred values (for call/return hooks) */
	unsigned short ftransfer; /* offset of first value transferred */
	unsigned short ntransfer; /* number of values transferred */
	} transferinfo;
	} u2;
	short nresults; /* expected number of results from this function */
	unsigned short callstatus;
	};


	/*
	** Bits in CallInfo status
	*/
	#define CIST_OAH (1<<0) /* original value of 'allowhook' */
	#define CIST_C (1<<1) /* call is running a C function */
	#define CIST_FRESH (1<<2) /* call is on a fresh "luaV_execute" frame */
	#define CIST_HOOKED (1<<3) /* call is running a debug hook */
	#define CIST_YPCALL (1<<4) /* doing a yieldable protected call */
	#define CIST_TAIL (1<<5) /* call was tail called */
	#define CIST_HOOKYIELD (1<<6) /* last hook called yielded */
	#define CIST_FIN (1<<7) /* function "called" a finalizer */
	#define CIST_TRAN (1<<8) /* 'ci' has transfer information */
	#define CIST_CLSRET (1<<9) /* function is closing tbc variables */
	/* Bits 10-12 are used for CIST_RECST (see below) */
	#define CIST_RECST 10
	#if defined(LUA_COMPAT_LT_LE)
	#define CIST_LEQ (1<<13) /* using __lt for __le */
	#endif


	/*
	** Field CIST_RECST stores the "recover status", used to keep the error
	** status while closing to-be-closed variables in coroutines, so that
	** Lua can correctly resume after an yield from a __close method called
	** because of an error. (Three bits are enough for error status.)
	*/
	#define getcistrecst(ci) (((ci)->callstatus >> CIST_RECST) & 7)
	#define setcistrecst(ci,st) \
	check_exp(((st) & 7) == (st), /* status must fit in three bits */ \
	((ci)->callstatus = ((ci)->callstatus & ~(7 << CIST_RECST)) \
	\| ((st) << CIST_RECST)))


	/* active function is a Lua function */
	#define isLua(ci) (!((ci)->callstatus & CIST_C))

	/* call is running Lua code (not a hook) */
	#define isLuacode(ci) (!((ci)->callstatus & (CIST_C \| CIST_HOOKED)))

	/* assume that CIST_OAH has offset 0 and that 'v' is strictly 0/1 */
	#define setoah(st,v) ((st) = ((st) & ~CIST_OAH) \| (v))
	#define getoah(st) ((st) & CIST_OAH)


	/*
	** 'global state', shared by all threads of this state
	*/
	typedef struct global_State {
	lua_Alloc frealloc; /* function to reallocate memory */
	void ud; / auxiliary data to 'frealloc' */
	l_mem totalbytes; /* number of bytes currently allocated - GCdebt */
	l_mem GCdebt; /* bytes allocated not yet compensated by the collector */
	lu_mem GCestimate; /* an estimate of the non-garbage memory in use */
	lu_mem lastatomic; /* see function 'genstep' in file 'lgc.c' */
	stringtable strt; /* hash table for strings */
	TValue l_registry;
	TValue nilvalue; /* a nil value */
	unsigned int seed; /* randomized seed for hashes */
	lu_byte currentwhite;
	lu_byte gcstate; /* state of garbage collector */
	lu_byte gckind; /* kind of GC running */
	lu_byte gcstopem; /* stops emergency collections */
	lu_byte genminormul; /* control for minor generational collections */
	lu_byte genmajormul; /* control for major generational collections */
	lu_byte gcstp; /* control whether GC is running */
	lu_byte gcemergency; /* true if this is an emergency collection */
	lu_byte gcpause; /* size of pause between successive GCs */
	lu_byte gcstepmul; /* GC "speed" */
	lu_byte gcstepsize; /* (log2 of) GC granularity */
	GCObject allgc; / list of all collectable objects */
	GCObject *sweepgc; / current position of sweep in list */
	GCObject finobj; / list of collectable objects with finalizers */
	GCObject gray; / list of gray objects */
	GCObject grayagain; / list of objects to be traversed atomically */
	GCObject weak; / list of tables with weak values */
	GCObject ephemeron; / list of ephemeron tables (weak keys) */
	GCObject allweak; / list of all-weak tables */
	GCObject tobefnz; / list of userdata to be GC */
	GCObject fixedgc; / list of objects not to be collected */
	/* fields for generational collector */
	GCObject survival; / start of objects that survived one GC cycle */
	GCObject old1; / start of old1 objects */
	GCObject reallyold; / objects more than one cycle old ("really old") */
	GCObject firstold1; / first OLD1 object in the list (if any) */
	GCObject finobjsur; / list of survival objects with finalizers */
	GCObject finobjold1; / list of old1 objects with finalizers */
	GCObject finobjrold; / list of really old objects with finalizers */
	struct lua_State twups; / list of threads with open upvalues */
	lua_CFunction panic; /* to be called in unprotected errors */
	struct lua_State *mainthread;
	TString memerrmsg; / message for memory-allocation errors */
	TString tmname[TM_N]; / array with tag-method names */
	struct Table mt[LUA_NUMTYPES]; / metatables for basic types */
	TString strcache[STRCACHE_N][STRCACHE_M]; / cache for strings in API */
	lua_WarnFunction warnf; /* warning function */
	void ud_warn; / auxiliary data to 'warnf' */
	} global_State;


	/*
	** 'per thread' state
	*/
	struct lua_State {
	CommonHeader;
	lu_byte status;
	lu_byte allowhook;
	unsigned short nci; /* number of items in 'ci' list */
	StkIdRel top; /* first free slot in the stack */
	global_State *l_G;
	CallInfo ci; / call info for current function */
	StkIdRel stack_last; /* end of stack (last element + 1) */
	StkIdRel stack; /* stack base */
	UpVal openupval; / list of open upvalues in this stack */
	StkIdRel tbclist; /* list of to-be-closed variables */
	GCObject *gclist;
	struct lua_State twups; / list of threads with open upvalues */
	struct lua_longjmp errorJmp; / current error recover point */
	CallInfo base_ci; /* CallInfo for first level (C calling Lua) */
	volatile lua_Hook hook;
	ptrdiff_t errfunc; /* current error handling function (stack index) */
	l_uint32 nCcalls; /* number of nested (non-yieldable \| C) calls */
	int oldpc; /* last pc traced */
	int basehookcount;
	int hookcount;
	volatile l_signalT hookmask;
	};


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

	/*
	** 'g->nilvalue' being a nil value flags that the state was completely
	** build.
	*/
	#define completestate(g) ttisnil(&g->nilvalue)


	/*
	** Union of all collectable objects (only for conversions)
	** ISO C99, 6.5.2.3 p.5:
	** "if a union contains several structures that share a common initial
	** sequence [...], and if the union object currently contains one
	** of these structures, it is permitted to inspect the common initial
	** part of any of them anywhere that a declaration of the complete type
	** of the union is visible."
	*/
	union GCUnion {
	GCObject gc; /* common header */
	struct TString ts;
	struct Udata u;
	union Closure cl;
	struct Table h;
	struct Proto p;
	struct lua_State th; /* thread */
	struct UpVal upv;
	};


	/*
	** ISO C99, 6.7.2.1 p.14:
	** "A pointer to a union object, suitably converted, points to each of
	** its members [...], and vice versa."
	*/
	#define cast_u(o) cast(union GCUnion *, (o))

	/* macros to convert a GCObject into a specific value */
	#define gco2ts(o) \
	check_exp(novariant((o)->tt) == LUA_TSTRING, &((cast_u(o))->ts))
	#define gco2u(o) check_exp((o)->tt == LUA_VUSERDATA, &((cast_u(o))->u))
	#define gco2lcl(o) check_exp((o)->tt == LUA_VLCL, &((cast_u(o))->cl.l))
	#define gco2ccl(o) check_exp((o)->tt == LUA_VCCL, &((cast_u(o))->cl.c))
	#define gco2cl(o) \
	check_exp(novariant((o)->tt) == LUA_TFUNCTION, &((cast_u(o))->cl))
	#define gco2t(o) check_exp((o)->tt == LUA_VTABLE, &((cast_u(o))->h))
	#define gco2p(o) check_exp((o)->tt == LUA_VPROTO, &((cast_u(o))->p))
	#define gco2th(o) check_exp((o)->tt == LUA_VTHREAD, &((cast_u(o))->th))
	#define gco2upv(o) check_exp((o)->tt == LUA_VUPVAL, &((cast_u(o))->upv))


	/*
	** macro to convert a Lua object into a GCObject
	** (The access to 'tt' tries to ensure that 'v' is actually a Lua object.)
	*/
	#define obj2gco(v) check_exp((v)->tt >= LUA_TSTRING, &(cast_u(v)->gc))


	/* actual number of total bytes allocated */
	#define gettotalbytes(g) cast(lu_mem, (g)->totalbytes + (g)->GCdebt)

	LUAI_FUNC void luaE_setdebt (global_State *g, l_mem debt);
	LUAI_FUNC void luaE_freethread (lua_State L, lua_State L1);
	LUAI_FUNC CallInfo luaE_extendCI (lua_State L);
	LUAI_FUNC void luaE_shrinkCI (lua_State *L);
	LUAI_FUNC void luaE_checkcstack (lua_State *L);
	LUAI_FUNC void luaE_incCstack (lua_State *L);
	LUAI_FUNC void luaE_warning (lua_State L, const char msg, int tocont);
	LUAI_FUNC void luaE_warnerror (lua_State L, const char where);
	LUAI_FUNC int luaE_resetthread (lua_State *L, int status);


	#endif