text: /*
  ** $Id: lobject.h,v 2.64 2011/10/31 17:48:22 roberto Exp $
  ** Type definitions for Lua objects
  ** See Copyright Notice in lua.h
  */
  
  
  #ifndef lobject_h
  #define lobject_h
  
  
  #include <stdarg.h>
  
  
  #include "llimits.h"
  #include "lua.h"
  
  
  /*
  ** Extra tags for non-values
  */
  #define LUA_TPROTO	LUA_NUMTAGS
  #define LUA_TUPVAL	(LUA_NUMTAGS+1)
  #define LUA_TDEADKEY	(LUA_NUMTAGS+2)
  
  /*
  ** number of all possible tags (including LUA_TNONE but excluding DEADKEY)
  */
  #define LUA_TOTALTAGS	(LUA_TUPVAL+2)
  
  
  /*
  ** tags for Tagged Values have the following use of bits:
  ** bits 0-3: actual tag (a LUA_T* value)
  ** bits 4-5: variant bits
  ** bit 6: whether value is collectable
  */
  
  /*
  ** LUA_TFUNCTION variants:
  ** 0 - Lua function
  ** 1 - light C function
  ** 2 - regular C function (closure)
  */
  
  /* Variant tags for functions */
  #define LUA_TLCL	(LUA_TFUNCTION | (0 << 4))  /* Lua closure */
  #define LUA_TLCF	(LUA_TFUNCTION | (1 << 4))  /* light C function */
  #define LUA_TCCL	(LUA_TFUNCTION | (2 << 4))  /* C closure */
  
  
  /* Bit mark for collectable types */
  #define BIT_ISCOLLECTABLE	(1 << 6)
  
  /* mark a tag as collectable */
  #define ctb(t)			((t) | BIT_ISCOLLECTABLE)
  
  
  /*
  ** Union of all collectable objects
  */
  typedef union GCObject GCObject;
  
  
  /*
  ** Common Header for all collectable objects (in macro form, to be
  ** included in other objects)
  */
  #define CommonHeader	GCObject *next; lu_byte tt; lu_byte marked
  
  
  /*
  ** Common header in struct form
  */
  typedef struct GCheader {
    CommonHeader;
  } GCheader;
  
  
  
  /*
  ** Union of all Lua values
  */
  typedef union Value Value;
  
  
  #define numfield	lua_Number n;    /* numbers */
  
  
  
  /*
  ** Tagged Values. This is the basic representation of values in Lua,
  ** an actual value plus a tag with its type.
  */
  
  #define TValuefields	Value value_; int tt_
  
  typedef struct lua_TValue TValue;
  
  
  /* macro defining a nil value */
  #define NILCONSTANT	{NULL}, LUA_TNIL
  
  
  #define val_(o)		((o)->value_)
  #define num_(o)		(val_(o).n)
  
  
  /* raw type tag of a TValue */
  #define rttype(o)	((o)->tt_)
  
  /* type tag of a TValue (bits 0-3 for tags + variant bits 4-5) */
  #define ttype(o)	(rttype(o) & 0x3F)
  
  
  /* type tag of a TValue with no variants (bits 0-3) */
  #define ttypenv(o)	(rttype(o) & 0x0F)
  
  
  /* Macros to test type */
  #define checktag(o,t)		(rttype(o) == (t))
  #define ttisnumber(o)		checktag((o), LUA_TNUMBER)
  #define ttisnil(o)		checktag((o), LUA_TNIL)
  #define ttisboolean(o)		checktag((o), LUA_TBOOLEAN)
  #define ttislightuserdata(o)	checktag((o), LUA_TLIGHTUSERDATA)
  #define ttisstring(o)		checktag((o), ctb(LUA_TSTRING))
  #define ttistable(o)		checktag((o), ctb(LUA_TTABLE))
  #define ttisfunction(o)		(ttypenv(o) == LUA_TFUNCTION)
  #define ttisclosure(o)		((rttype(o) & 0x1F) == LUA_TFUNCTION)
  #define ttisCclosure(o)		checktag((o), ctb(LUA_TCCL))
  #define ttisLclosure(o)		checktag((o), ctb(LUA_TLCL))
  #define ttislcf(o)		checktag((o), LUA_TLCF)
  #define ttisuserdata(o)		checktag((o), ctb(LUA_TUSERDATA))
  #define ttisthread(o)		checktag((o), ctb(LUA_TTHREAD))
  #define ttisdeadkey(o)		checktag((o), LUA_TDEADKEY)
  
  #define ttisequal(o1,o2)	(rttype(o1) == rttype(o2))
  
  /* Macros to access values */
  #define nvalue(o)	check_exp(ttisnumber(o), num_(o))
  #define gcvalue(o)	check_exp(iscollectable(o), val_(o).gc)
  #define pvalue(o)	check_exp(ttislightuserdata(o), val_(o).p)
  #define rawtsvalue(o)	check_exp(ttisstring(o), &val_(o).gc->ts)
  #define tsvalue(o)	(&rawtsvalue(o)->tsv)
  #define rawuvalue(o)	check_exp(ttisuserdata(o), &val_(o).gc->u)
  #define uvalue(o)	(&rawuvalue(o)->uv)
  #define clvalue(o)	check_exp(ttisclosure(o), &val_(o).gc->cl)
  #define clLvalue(o)	check_exp(ttisLclosure(o), &val_(o).gc->cl.l)
  #define clCvalue(o)	check_exp(ttisCclosure(o), &val_(o).gc->cl.c)
  #define fvalue(o)	check_exp(ttislcf(o), val_(o).f)
  #define hvalue(o)	check_exp(ttistable(o), &val_(o).gc->h)
  #define bvalue(o)	check_exp(ttisboolean(o), val_(o).b)
  #define thvalue(o)	check_exp(ttisthread(o), &val_(o).gc->th)
  /* a dead value may get the 'gc' field, but cannot access its contents */
  #define deadvalue(o)	check_exp(ttisdeadkey(o), cast(void *, val_(o).gc))
  
  #define l_isfalse(o)	(ttisnil(o) || (ttisboolean(o) && bvalue(o) == 0))
  
  
  #define iscollectable(o)	(rttype(o) & BIT_ISCOLLECTABLE)
  
  
  /* Macros for internal tests */
  #define righttt(obj)		(ttypenv(obj) == gcvalue(obj)->gch.tt)
  
  #define checkliveness(g,obj) \
  	lua_longassert(!iscollectable(obj) || \
  			(righttt(obj) && !isdead(g,gcvalue(obj))))
  
  
  /* Macros to set values */
  #define settt_(o,t)	((o)->tt_=(t))
  
  #define setnvalue(obj,x) \
    { TValue *io=(obj); num_(io)=(x); settt_(io, LUA_TNUMBER); }
  
  #define changenvalue(o,x)	check_exp(ttisnumber(o), num_(o)=(x))
  
  #define setnilvalue(obj) settt_(obj, LUA_TNIL)
  
  #define setfvalue(obj,x) \
    { TValue *io=(obj); val_(io).f=(x); settt_(io, LUA_TLCF); }
  
  #define setpvalue(obj,x) \
    { TValue *io=(obj); val_(io).p=(x); settt_(io, LUA_TLIGHTUSERDATA); }
  
  #define setbvalue(obj,x) \
    { TValue *io=(obj); val_(io).b=(x); settt_(io, LUA_TBOOLEAN); }
  
  #define setgcovalue(L,obj,x) \
    { TValue *io=(obj); GCObject *i_g=(x); \
      val_(io).gc=i_g; settt_(io, ctb(gch(i_g)->tt)); }
  
  #define setsvalue(L,obj,x) \
    { TValue *io=(obj); \
      val_(io).gc=cast(GCObject *, (x)); settt_(io, ctb(LUA_TSTRING)); \
      checkliveness(G(L),io); }
  
  #define setuvalue(L,obj,x) \
    { TValue *io=(obj); \
      val_(io).gc=cast(GCObject *, (x)); settt_(io, ctb(LUA_TUSERDATA)); \
      checkliveness(G(L),io); }
  
  #define setthvalue(L,obj,x) \
    { TValue *io=(obj); \
      val_(io).gc=cast(GCObject *, (x)); settt_(io, ctb(LUA_TTHREAD)); \
      checkliveness(G(L),io); }
  
  #define setclLvalue(L,obj,x) \
    { TValue *io=(obj); \
      val_(io).gc=cast(GCObject *, (x)); settt_(io, ctb(LUA_TLCL)); \
      checkliveness(G(L),io); }
  
  #define setclCvalue(L,obj,x) \
    { TValue *io=(obj); \
      val_(io).gc=cast(GCObject *, (x)); settt_(io, ctb(LUA_TCCL)); \
      checkliveness(G(L),io); }
  
  #define sethvalue(L,obj,x) \
    { TValue *io=(obj); \
      val_(io).gc=cast(GCObject *, (x)); settt_(io, ctb(LUA_TTABLE)); \
      checkliveness(G(L),io); }
  
  #define setptvalue(L,obj,x) \
    { TValue *io=(obj); \
      val_(io).gc=cast(GCObject *, (x)); settt_(io, ctb(LUA_TPROTO)); \
      checkliveness(G(L),io); }
  
  #define setdeadvalue(obj)	settt_(obj, LUA_TDEADKEY)
  
  
  
  #define setobj(L,obj1,obj2) \
  	{ const TValue *io2=(obj2); TValue *io1=(obj1); \
  	  io1->value_ = io2->value_; io1->tt_ = io2->tt_; \
  	  checkliveness(G(L),io1); }
  
  
  /*
  ** different types of assignments, according to destination
  */
  
  /* from stack to (same) stack */
  #define setobjs2s	setobj
  /* to stack (not from same stack) */
  #define setobj2s	setobj
  #define setsvalue2s	setsvalue
  #define sethvalue2s	sethvalue
  #define setptvalue2s	setptvalue
  /* from table to same table */
  #define setobjt2t	setobj
  /* to table */
  #define setobj2t	setobj
  /* to new object */
  #define setobj2n	setobj
  #define setsvalue2n	setsvalue
  
  
  
  
  /*
  ** {======================================================
  ** NaN Trick
  ** =======================================================
  */
  
  #if defined(LUA_NANTRICK) \
   || defined(LUA_NANTRICK_LE) \
   || defined(LUA_NANTRICK_BE)
  
  /*
  ** numbers are represented in the 'd_' field. All other values have the
  ** value (NNMARK | tag) in 'tt__'. A number with such pattern would be
  ** a "signaled NaN", which is never generated by regular operations by
  ** the CPU (nor by 'strtod')
  */
  #if !defined(NNMARK)
  #define NNMARK		0x7FF7A500
  #define NNMASK		0x7FFFFF00
  #endif
  
  #undef TValuefields
  #undef NILCONSTANT
  
  #if defined(LUA_NANTRICK_LE)
  
  /* little endian */
  #define TValuefields  \
  	union { struct { Value v__; int tt__; } i; double d__; } u
  #define NILCONSTANT	{{{NULL}, tag2tt(LUA_TNIL)}}
  /* field-access macros */
  #define v_(o)		((o)->u.i.v__)
  #define d_(o)		((o)->u.d__)
  #define tt_(o)		((o)->u.i.tt__)
  
  #elif defined(LUA_NANTRICK_BE)
  
  /* big endian */
  #define TValuefields  \
  	union { struct { int tt__; Value v__; } i; double d__; } u
  #define NILCONSTANT	{{tag2tt(LUA_TNIL), {NULL}}}
  /* field-access macros */
  #define v_(o)		((o)->u.i.v__)
  #define d_(o)		((o)->u.d__)
  #define tt_(o)		((o)->u.i.tt__)
  
  #elif !defined(TValuefields)
  #error option 'LUA_NANTRICK' needs declaration for 'TValuefields'
  
  #endif
  
  
  /* correspondence with standard representation */
  #undef val_
  #define val_(o)		v_(o)
  #undef num_
  #define num_(o)		d_(o)
  
  
  #undef numfield
  #define numfield	/* no such field; numbers are the entire struct */
  
  /* basic check to distinguish numbers from non-numbers */
  #undef ttisnumber
  #define ttisnumber(o)	((tt_(o) & NNMASK) != NNMARK)
  
  #define tag2tt(t)	(NNMARK | (t))
  
  #undef rttype
  #define rttype(o)	(ttisnumber(o) ? LUA_TNUMBER : tt_(o) & 0xff)
  
  #undef settt_
  #define settt_(o,t)	(tt_(o) = tag2tt(t))
  
  #undef setnvalue
  #define setnvalue(obj,x) \
  	{ TValue *io_=(obj); num_(io_)=(x); lua_assert(ttisnumber(io_)); }
  
  #undef setobj
  #define setobj(L,obj1,obj2) \
  	{ const TValue *o2_=(obj2); TValue *o1_=(obj1); \
  	  o1_->u = o2_->u; \
  	  checkliveness(G(L),o1_); }
  
  
  /*
  ** these redefinitions are not mandatory, but these forms are more efficient
  */
  
  #undef checktag
  #define checktag(o,t)	(tt_(o) == tag2tt(t))
  
  #undef ttisequal
  #define ttisequal(o1,o2)  \
  	(ttisnumber(o1) ? ttisnumber(o2) : (tt_(o1) == tt_(o2)))
  
  
  
  #define luai_checknum(L,o,c)	{ if (!ttisnumber(o)) c; }
  
  
  #else
  
  #define luai_checknum(L,o,c)	{ /* empty */ }
  
  #endif
  /* }====================================================== */
  
  
  
  /*
  ** {======================================================
  ** types and prototypes
  ** =======================================================
  */
  
  
  union Value {
    GCObject *gc;    /* collectable objects */
    void *p;         /* light userdata */
    int b;           /* booleans */
    lua_CFunction f; /* light C functions */
    numfield         /* numbers */
  };
  
  
  struct lua_TValue {
    TValuefields;
  };
  
  
  typedef TValue *StkId;  /* index to stack elements */
  
  
  
  
  /*
  ** Header for string value; string bytes follow the end of this structure
  */
  typedef union TString {
    L_Umaxalign dummy;  /* ensures maximum alignment for strings */
    struct {
      CommonHeader;
      lu_byte reserved;
      unsigned int hash;
      size_t len;  /* number of characters in string */
    } tsv;
  } TString;
  
  
  /* get the actual string (array of bytes) from a TString */
  #define getstr(ts)	cast(const char *, (ts) + 1)
  
  /* get the actual string (array of bytes) from a Lua value */
  #define svalue(o)       getstr(rawtsvalue(o))
  
  
  /*
  ** Header for userdata; memory area follows the end of this structure
  */
  typedef union Udata {
    L_Umaxalign dummy;  /* ensures maximum alignment for `local' udata */
    struct {
      CommonHeader;
      struct Table *metatable;
      struct Table *env;
      size_t len;  /* number of bytes */
    } uv;
  } Udata;
  
  
  
  /*
  ** Description of an upvalue for function prototypes
  */
  typedef struct Upvaldesc {
    TString *name;  /* upvalue name (for debug information) */
    lu_byte instack;  /* whether it is in stack */
    lu_byte idx;  /* index of upvalue (in stack or in outer function's list) */
  } Upvaldesc;
  
  
  /*
  ** Description of a local variable for function prototypes
  ** (used for debug information)
  */
  typedef struct LocVar {
    TString *varname;
    int startpc;  /* first point where variable is active */
    int endpc;    /* first point where variable is dead */
  } LocVar;
  
  
  /*
  ** Function Prototypes
  */
  typedef struct Proto {
    CommonHeader;
    TValue *k;  /* constants used by the function */
    Instruction *code;
    struct Proto **p;  /* functions defined inside the function */
    int *lineinfo;  /* map from opcodes to source lines (debug information) */
    LocVar *locvars;  /* information about local variables (debug information) */
    Upvaldesc *upvalues;  /* upvalue information */
    union Closure *cache;  /* last created closure with this prototype */
    TString  *source;  /* used for debug information */
    int sizeupvalues;  /* size of 'upvalues' */
    int sizek;  /* size of `k' */
    int sizecode;
    int sizelineinfo;
    int sizep;  /* size of `p' */
    int sizelocvars;
    int linedefined;
    int lastlinedefined;
    GCObject *gclist;
    lu_byte numparams;  /* number of fixed parameters */
    lu_byte is_vararg;
    lu_byte maxstacksize;  /* maximum stack used by this function */
  } Proto;
  
  
  
  /*
  ** Lua Upvalues
  */
  typedef struct UpVal {
    CommonHeader;
    TValue *v;  /* points to stack or to its own value */
    union {
      TValue value;  /* the value (when closed) */
      struct {  /* double linked list (when open) */
        struct UpVal *prev;
        struct UpVal *next;
      } l;
    } u;
  } UpVal;
  
  
  /*
  ** Closures
  */
  
  #define ClosureHeader \
  	CommonHeader; lu_byte isC; lu_byte nupvalues; GCObject *gclist
  
  typedef struct CClosure {
    ClosureHeader;
    lua_CFunction f;
    TValue upvalue[1];  /* list of upvalues */
  } CClosure;
  
  
  typedef struct LClosure {
    ClosureHeader;
    struct Proto *p;
    UpVal *upvals[1];  /* list of upvalues */
  } LClosure;
  
  
  typedef union Closure {
    CClosure c;
    LClosure l;
  } Closure;
  
  
  #define isLfunction(o)	ttisLclosure(o)
  
  #define getproto(o)	(clLvalue(o)->p)
  
  
  /*
  ** Tables
  */
  
  typedef union TKey {
    struct {
      TValuefields;
      struct Node *next;  /* for chaining */
    } nk;
    TValue tvk;
  } TKey;
  
  
  typedef struct Node {
    TValue i_val;
    TKey i_key;
  } Node;
  
  
  typedef struct Table {
    CommonHeader;
    lu_byte flags;  /* 1<<p means tagmethod(p) is not present */
    lu_byte lsizenode;  /* log2 of size of `node' array */
    struct Table *metatable;
    TValue *array;  /* array part */
    Node *node;
    Node *lastfree;  /* any free position is before this position */
    GCObject *gclist;
    int sizearray;  /* size of `array' array */
  } Table;
  
  
  
  /*
  ** `module' operation for hashing (size is always a power of 2)
  */
  #define lmod(s,size) \
  	(check_exp((size&(size-1))==0, (cast(int, (s) & ((size)-1)))))
  
  
  #define twoto(x)	(1<<(x))
  #define sizenode(t)	(twoto((t)->lsizenode))
  
  
  /*
  ** (address of) a fixed nil value
  */
  #define luaO_nilobject		(&luaO_nilobject_)
  
  
  LUAI_DDEC const TValue luaO_nilobject_;
  
  
  LUAI_FUNC int luaO_int2fb (unsigned int x);
  LUAI_FUNC int luaO_fb2int (int x);
  LUAI_FUNC int luaO_ceillog2 (unsigned int x);
  LUAI_FUNC lua_Number luaO_arith (int op, lua_Number v1, lua_Number v2);
  LUAI_FUNC int luaO_str2d (const char *s, size_t len, lua_Number *result);
  LUAI_FUNC int luaO_hexavalue (int c);
  LUAI_FUNC const char *luaO_pushvfstring (lua_State *L, const char *fmt,
                                                         va_list argp);
  LUAI_FUNC const char *luaO_pushfstring (lua_State *L, const char *fmt, ...);
  LUAI_FUNC void luaO_chunkid (char *out, const char *source, size_t len);
  
  
  #endif
  
  