Home | History | Annotate | Download | only in src
      1 /*
      2 ** $Id: lobject.h,v 2.71 2012/09/11 18:21:44 roberto Exp $
      3 ** Type definitions for Lua objects
      4 ** See Copyright Notice in lua.h
      5 */
      6 
      7 
      8 #ifndef lobject_h
      9 #define lobject_h
     10 
     11 
     12 #include <stdarg.h>
     13 
     14 
     15 #include "llimits.h"
     16 #include "lua.h"
     17 
     18 
     19 /*
     20 ** Extra tags for non-values
     21 */
     22 #define LUA_TPROTO	LUA_NUMTAGS
     23 #define LUA_TUPVAL	(LUA_NUMTAGS+1)
     24 #define LUA_TDEADKEY	(LUA_NUMTAGS+2)
     25 
     26 /*
     27 ** number of all possible tags (including LUA_TNONE but excluding DEADKEY)
     28 */
     29 #define LUA_TOTALTAGS	(LUA_TUPVAL+2)
     30 
     31 
     32 /*
     33 ** tags for Tagged Values have the following use of bits:
     34 ** bits 0-3: actual tag (a LUA_T* value)
     35 ** bits 4-5: variant bits
     36 ** bit 6: whether value is collectable
     37 */
     38 
     39 #define VARBITS		(3 << 4)
     40 
     41 
     42 /*
     43 ** LUA_TFUNCTION variants:
     44 ** 0 - Lua function
     45 ** 1 - light C function
     46 ** 2 - regular C function (closure)
     47 */
     48 
     49 /* Variant tags for functions */
     50 #define LUA_TLCL	(LUA_TFUNCTION | (0 << 4))  /* Lua closure */
     51 #define LUA_TLCF	(LUA_TFUNCTION | (1 << 4))  /* light C function */
     52 #define LUA_TCCL	(LUA_TFUNCTION | (2 << 4))  /* C closure */
     53 
     54 
     55 /* Variant tags for strings */
     56 #define LUA_TSHRSTR	(LUA_TSTRING | (0 << 4))  /* short strings */
     57 #define LUA_TLNGSTR	(LUA_TSTRING | (1 << 4))  /* long strings */
     58 
     59 
     60 /* Bit mark for collectable types */
     61 #define BIT_ISCOLLECTABLE	(1 << 6)
     62 
     63 /* mark a tag as collectable */
     64 #define ctb(t)			((t) | BIT_ISCOLLECTABLE)
     65 
     66 
     67 /*
     68 ** Union of all collectable objects
     69 */
     70 typedef union GCObject GCObject;
     71 
     72 
     73 /*
     74 ** Common Header for all collectable objects (in macro form, to be
     75 ** included in other objects)
     76 */
     77 #define CommonHeader	GCObject *next; lu_byte tt; lu_byte marked
     78 
     79 
     80 /*
     81 ** Common header in struct form
     82 */
     83 typedef struct GCheader {
     84   CommonHeader;
     85 } GCheader;
     86 
     87 
     88 
     89 /*
     90 ** Union of all Lua values
     91 */
     92 typedef union Value Value;
     93 
     94 
     95 #define numfield	lua_Number n;    /* numbers */
     96 
     97 
     98 
     99 /*
    100 ** Tagged Values. This is the basic representation of values in Lua,
    101 ** an actual value plus a tag with its type.
    102 */
    103 
    104 #define TValuefields	Value value_; int tt_
    105 
    106 typedef struct lua_TValue TValue;
    107 
    108 
    109 /* macro defining a nil value */
    110 #define NILCONSTANT	{NULL}, LUA_TNIL
    111 
    112 
    113 #define val_(o)		((o)->value_)
    114 #define num_(o)		(val_(o).n)
    115 
    116 
    117 /* raw type tag of a TValue */
    118 #define rttype(o)	((o)->tt_)
    119 
    120 /* tag with no variants (bits 0-3) */
    121 #define novariant(x)	((x) & 0x0F)
    122 
    123 /* type tag of a TValue (bits 0-3 for tags + variant bits 4-5) */
    124 #define ttype(o)	(rttype(o) & 0x3F)
    125 
    126 /* type tag of a TValue with no variants (bits 0-3) */
    127 #define ttypenv(o)	(novariant(rttype(o)))
    128 
    129 
    130 /* Macros to test type */
    131 #define checktag(o,t)		(rttype(o) == (t))
    132 #define checktype(o,t)		(ttypenv(o) == (t))
    133 #define ttisnumber(o)		checktag((o), LUA_TNUMBER)
    134 #define ttisnil(o)		checktag((o), LUA_TNIL)
    135 #define ttisboolean(o)		checktag((o), LUA_TBOOLEAN)
    136 #define ttislightuserdata(o)	checktag((o), LUA_TLIGHTUSERDATA)
    137 #define ttisstring(o)		checktype((o), LUA_TSTRING)
    138 #define ttisshrstring(o)	checktag((o), ctb(LUA_TSHRSTR))
    139 #define ttislngstring(o)	checktag((o), ctb(LUA_TLNGSTR))
    140 #define ttistable(o)		checktag((o), ctb(LUA_TTABLE))
    141 #define ttisfunction(o)		checktype(o, LUA_TFUNCTION)
    142 #define ttisclosure(o)		((rttype(o) & 0x1F) == LUA_TFUNCTION)
    143 #define ttisCclosure(o)		checktag((o), ctb(LUA_TCCL))
    144 #define ttisLclosure(o)		checktag((o), ctb(LUA_TLCL))
    145 #define ttislcf(o)		checktag((o), LUA_TLCF)
    146 #define ttisuserdata(o)		checktag((o), ctb(LUA_TUSERDATA))
    147 #define ttisthread(o)		checktag((o), ctb(LUA_TTHREAD))
    148 #define ttisdeadkey(o)		checktag((o), LUA_TDEADKEY)
    149 
    150 #define ttisequal(o1,o2)	(rttype(o1) == rttype(o2))
    151 
    152 /* Macros to access values */
    153 #define nvalue(o)	check_exp(ttisnumber(o), num_(o))
    154 #define gcvalue(o)	check_exp(iscollectable(o), val_(o).gc)
    155 #define pvalue(o)	check_exp(ttislightuserdata(o), val_(o).p)
    156 #define rawtsvalue(o)	check_exp(ttisstring(o), &val_(o).gc->ts)
    157 #define tsvalue(o)	(&rawtsvalue(o)->tsv)
    158 #define rawuvalue(o)	check_exp(ttisuserdata(o), &val_(o).gc->u)
    159 #define uvalue(o)	(&rawuvalue(o)->uv)
    160 #define clvalue(o)	check_exp(ttisclosure(o), &val_(o).gc->cl)
    161 #define clLvalue(o)	check_exp(ttisLclosure(o), &val_(o).gc->cl.l)
    162 #define clCvalue(o)	check_exp(ttisCclosure(o), &val_(o).gc->cl.c)
    163 #define fvalue(o)	check_exp(ttislcf(o), val_(o).f)
    164 #define hvalue(o)	check_exp(ttistable(o), &val_(o).gc->h)
    165 #define bvalue(o)	check_exp(ttisboolean(o), val_(o).b)
    166 #define thvalue(o)	check_exp(ttisthread(o), &val_(o).gc->th)
    167 /* a dead value may get the 'gc' field, but cannot access its contents */
    168 #define deadvalue(o)	check_exp(ttisdeadkey(o), cast(void *, val_(o).gc))
    169 
    170 #define l_isfalse(o)	(ttisnil(o) || (ttisboolean(o) && bvalue(o) == 0))
    171 
    172 
    173 #define iscollectable(o)	(rttype(o) & BIT_ISCOLLECTABLE)
    174 
    175 
    176 /* Macros for internal tests */
    177 #define righttt(obj)		(ttype(obj) == gcvalue(obj)->gch.tt)
    178 
    179 #define checkliveness(g,obj) \
    180 	lua_longassert(!iscollectable(obj) || \
    181 			(righttt(obj) && !isdead(g,gcvalue(obj))))
    182 
    183 
    184 /* Macros to set values */
    185 #define settt_(o,t)	((o)->tt_=(t))
    186 
    187 #define setnvalue(obj,x) \
    188   { TValue *io=(obj); num_(io)=(x); settt_(io, LUA_TNUMBER); }
    189 
    190 #define setnilvalue(obj) settt_(obj, LUA_TNIL)
    191 
    192 #define setfvalue(obj,x) \
    193   { TValue *io=(obj); val_(io).f=(x); settt_(io, LUA_TLCF); }
    194 
    195 #define setpvalue(obj,x) \
    196   { TValue *io=(obj); val_(io).p=(x); settt_(io, LUA_TLIGHTUSERDATA); }
    197 
    198 #define setbvalue(obj,x) \
    199   { TValue *io=(obj); val_(io).b=(x); settt_(io, LUA_TBOOLEAN); }
    200 
    201 #define setgcovalue(L,obj,x) \
    202   { TValue *io=(obj); GCObject *i_g=(x); \
    203     val_(io).gc=i_g; settt_(io, ctb(gch(i_g)->tt)); }
    204 
    205 #define setsvalue(L,obj,x) \
    206   { TValue *io=(obj); \
    207     TString *x_ = (x); \
    208     val_(io).gc=cast(GCObject *, x_); settt_(io, ctb(x_->tsv.tt)); \
    209     checkliveness(G(L),io); }
    210 
    211 #define setuvalue(L,obj,x) \
    212   { TValue *io=(obj); \
    213     val_(io).gc=cast(GCObject *, (x)); settt_(io, ctb(LUA_TUSERDATA)); \
    214     checkliveness(G(L),io); }
    215 
    216 #define setthvalue(L,obj,x) \
    217   { TValue *io=(obj); \
    218     val_(io).gc=cast(GCObject *, (x)); settt_(io, ctb(LUA_TTHREAD)); \
    219     checkliveness(G(L),io); }
    220 
    221 #define setclLvalue(L,obj,x) \
    222   { TValue *io=(obj); \
    223     val_(io).gc=cast(GCObject *, (x)); settt_(io, ctb(LUA_TLCL)); \
    224     checkliveness(G(L),io); }
    225 
    226 #define setclCvalue(L,obj,x) \
    227   { TValue *io=(obj); \
    228     val_(io).gc=cast(GCObject *, (x)); settt_(io, ctb(LUA_TCCL)); \
    229     checkliveness(G(L),io); }
    230 
    231 #define sethvalue(L,obj,x) \
    232   { TValue *io=(obj); \
    233     val_(io).gc=cast(GCObject *, (x)); settt_(io, ctb(LUA_TTABLE)); \
    234     checkliveness(G(L),io); }
    235 
    236 #define setdeadvalue(obj)	settt_(obj, LUA_TDEADKEY)
    237 
    238 
    239 
    240 #define setobj(L,obj1,obj2) \
    241 	{ const TValue *io2=(obj2); TValue *io1=(obj1); \
    242 	  io1->value_ = io2->value_; io1->tt_ = io2->tt_; \
    243 	  checkliveness(G(L),io1); }
    244 
    245 
    246 /*
    247 ** different types of assignments, according to destination
    248 */
    249 
    250 /* from stack to (same) stack */
    251 #define setobjs2s	setobj
    252 /* to stack (not from same stack) */
    253 #define setobj2s	setobj
    254 #define setsvalue2s	setsvalue
    255 #define sethvalue2s	sethvalue
    256 #define setptvalue2s	setptvalue
    257 /* from table to same table */
    258 #define setobjt2t	setobj
    259 /* to table */
    260 #define setobj2t	setobj
    261 /* to new object */
    262 #define setobj2n	setobj
    263 #define setsvalue2n	setsvalue
    264 
    265 
    266 /* check whether a number is valid (useful only for NaN trick) */
    267 #define luai_checknum(L,o,c)	{ /* empty */ }
    268 
    269 
    270 /*
    271 ** {======================================================
    272 ** NaN Trick
    273 ** =======================================================
    274 */
    275 #if defined(LUA_NANTRICK)
    276 
    277 /*
    278 ** numbers are represented in the 'd_' field. All other values have the
    279 ** value (NNMARK | tag) in 'tt__'. A number with such pattern would be
    280 ** a "signaled NaN", which is never generated by regular operations by
    281 ** the CPU (nor by 'strtod')
    282 */
    283 
    284 /* allows for external implementation for part of the trick */
    285 #if !defined(NNMARK)	/* { */
    286 
    287 
    288 #if !defined(LUA_IEEEENDIAN)
    289 #error option 'LUA_NANTRICK' needs 'LUA_IEEEENDIAN'
    290 #endif
    291 
    292 
    293 #define NNMARK		0x7FF7A500
    294 #define NNMASK		0x7FFFFF00
    295 
    296 #undef TValuefields
    297 #undef NILCONSTANT
    298 
    299 #if (LUA_IEEEENDIAN == 0)	/* { */
    300 
    301 /* little endian */
    302 #define TValuefields  \
    303 	union { struct { Value v__; int tt__; } i; double d__; } u
    304 #define NILCONSTANT	{{{NULL}, tag2tt(LUA_TNIL)}}
    305 /* field-access macros */
    306 #define v_(o)		((o)->u.i.v__)
    307 #define d_(o)		((o)->u.d__)
    308 #define tt_(o)		((o)->u.i.tt__)
    309 
    310 #else				/* }{ */
    311 
    312 /* big endian */
    313 #define TValuefields  \
    314 	union { struct { int tt__; Value v__; } i; double d__; } u
    315 #define NILCONSTANT	{{tag2tt(LUA_TNIL), {NULL}}}
    316 /* field-access macros */
    317 #define v_(o)		((o)->u.i.v__)
    318 #define d_(o)		((o)->u.d__)
    319 #define tt_(o)		((o)->u.i.tt__)
    320 
    321 #endif				/* } */
    322 
    323 #endif			/* } */
    324 
    325 
    326 /* correspondence with standard representation */
    327 #undef val_
    328 #define val_(o)		v_(o)
    329 #undef num_
    330 #define num_(o)		d_(o)
    331 
    332 
    333 #undef numfield
    334 #define numfield	/* no such field; numbers are the entire struct */
    335 
    336 /* basic check to distinguish numbers from non-numbers */
    337 #undef ttisnumber
    338 #define ttisnumber(o)	((tt_(o) & NNMASK) != NNMARK)
    339 
    340 #define tag2tt(t)	(NNMARK | (t))
    341 
    342 #undef rttype
    343 #define rttype(o)	(ttisnumber(o) ? LUA_TNUMBER : tt_(o) & 0xff)
    344 
    345 #undef settt_
    346 #define settt_(o,t)	(tt_(o) = tag2tt(t))
    347 
    348 #undef setnvalue
    349 #define setnvalue(obj,x) \
    350 	{ TValue *io_=(obj); num_(io_)=(x); lua_assert(ttisnumber(io_)); }
    351 
    352 #undef setobj
    353 #define setobj(L,obj1,obj2) \
    354 	{ const TValue *o2_=(obj2); TValue *o1_=(obj1); \
    355 	  o1_->u = o2_->u; \
    356 	  checkliveness(G(L),o1_); }
    357 
    358 
    359 /*
    360 ** these redefinitions are not mandatory, but these forms are more efficient
    361 */
    362 
    363 #undef checktag
    364 #undef checktype
    365 #define checktag(o,t)	(tt_(o) == tag2tt(t))
    366 #define checktype(o,t)	(ctb(tt_(o) | VARBITS) == ctb(tag2tt(t) | VARBITS))
    367 
    368 #undef ttisequal
    369 #define ttisequal(o1,o2)  \
    370 	(ttisnumber(o1) ? ttisnumber(o2) : (tt_(o1) == tt_(o2)))
    371 
    372 
    373 #undef luai_checknum
    374 #define luai_checknum(L,o,c)	{ if (!ttisnumber(o)) c; }
    375 
    376 #endif
    377 /* }====================================================== */
    378 
    379 
    380 
    381 /*
    382 ** {======================================================
    383 ** types and prototypes
    384 ** =======================================================
    385 */
    386 
    387 
    388 union Value {
    389   GCObject *gc;    /* collectable objects */
    390   void *p;         /* light userdata */
    391   int b;           /* booleans */
    392   lua_CFunction f; /* light C functions */
    393   numfield         /* numbers */
    394 };
    395 
    396 
    397 struct lua_TValue {
    398   TValuefields;
    399 };
    400 
    401 
    402 typedef TValue *StkId;  /* index to stack elements */
    403 
    404 
    405 
    406 
    407 /*
    408 ** Header for string value; string bytes follow the end of this structure
    409 */
    410 typedef union TString {
    411   L_Umaxalign dummy;  /* ensures maximum alignment for strings */
    412   struct {
    413     CommonHeader;
    414     lu_byte extra;  /* reserved words for short strings; "has hash" for longs */
    415     unsigned int hash;
    416     size_t len;  /* number of characters in string */
    417   } tsv;
    418 } TString;
    419 
    420 
    421 /* get the actual string (array of bytes) from a TString */
    422 #define getstr(ts)	cast(const char *, (ts) + 1)
    423 
    424 /* get the actual string (array of bytes) from a Lua value */
    425 #define svalue(o)       getstr(rawtsvalue(o))
    426 
    427 
    428 /*
    429 ** Header for userdata; memory area follows the end of this structure
    430 */
    431 typedef union Udata {
    432   L_Umaxalign dummy;  /* ensures maximum alignment for `local' udata */
    433   struct {
    434     CommonHeader;
    435     struct Table *metatable;
    436     struct Table *env;
    437     size_t len;  /* number of bytes */
    438   } uv;
    439 } Udata;
    440 
    441 
    442 
    443 /*
    444 ** Description of an upvalue for function prototypes
    445 */
    446 typedef struct Upvaldesc {
    447   TString *name;  /* upvalue name (for debug information) */
    448   lu_byte instack;  /* whether it is in stack */
    449   lu_byte idx;  /* index of upvalue (in stack or in outer function's list) */
    450 } Upvaldesc;
    451 
    452 
    453 /*
    454 ** Description of a local variable for function prototypes
    455 ** (used for debug information)
    456 */
    457 typedef struct LocVar {
    458   TString *varname;
    459   int startpc;  /* first point where variable is active */
    460   int endpc;    /* first point where variable is dead */
    461 } LocVar;
    462 
    463 
    464 /*
    465 ** Function Prototypes
    466 */
    467 typedef struct Proto {
    468   CommonHeader;
    469   TValue *k;  /* constants used by the function */
    470   Instruction *code;
    471   struct Proto **p;  /* functions defined inside the function */
    472   int *lineinfo;  /* map from opcodes to source lines (debug information) */
    473   LocVar *locvars;  /* information about local variables (debug information) */
    474   Upvaldesc *upvalues;  /* upvalue information */
    475   union Closure *cache;  /* last created closure with this prototype */
    476   TString  *source;  /* used for debug information */
    477   int sizeupvalues;  /* size of 'upvalues' */
    478   int sizek;  /* size of `k' */
    479   int sizecode;
    480   int sizelineinfo;
    481   int sizep;  /* size of `p' */
    482   int sizelocvars;
    483   int linedefined;
    484   int lastlinedefined;
    485   GCObject *gclist;
    486   lu_byte numparams;  /* number of fixed parameters */
    487   lu_byte is_vararg;
    488   lu_byte maxstacksize;  /* maximum stack used by this function */
    489 } Proto;
    490 
    491 
    492 
    493 /*
    494 ** Lua Upvalues
    495 */
    496 typedef struct UpVal {
    497   CommonHeader;
    498   TValue *v;  /* points to stack or to its own value */
    499   union {
    500     TValue value;  /* the value (when closed) */
    501     struct {  /* double linked list (when open) */
    502       struct UpVal *prev;
    503       struct UpVal *next;
    504     } l;
    505   } u;
    506 } UpVal;
    507 
    508 
    509 /*
    510 ** Closures
    511 */
    512 
    513 #define ClosureHeader \
    514 	CommonHeader; lu_byte nupvalues; GCObject *gclist
    515 
    516 typedef struct CClosure {
    517   ClosureHeader;
    518   lua_CFunction f;
    519   TValue upvalue[1];  /* list of upvalues */
    520 } CClosure;
    521 
    522 
    523 typedef struct LClosure {
    524   ClosureHeader;
    525   struct Proto *p;
    526   UpVal *upvals[1];  /* list of upvalues */
    527 } LClosure;
    528 
    529 
    530 typedef union Closure {
    531   CClosure c;
    532   LClosure l;
    533 } Closure;
    534 
    535 
    536 #define isLfunction(o)	ttisLclosure(o)
    537 
    538 #define getproto(o)	(clLvalue(o)->p)
    539 
    540 
    541 /*
    542 ** Tables
    543 */
    544 
    545 typedef union TKey {
    546   struct {
    547     TValuefields;
    548     struct Node *next;  /* for chaining */
    549   } nk;
    550   TValue tvk;
    551 } TKey;
    552 
    553 
    554 typedef struct Node {
    555   TValue i_val;
    556   TKey i_key;
    557 } Node;
    558 
    559 
    560 typedef struct Table {
    561   CommonHeader;
    562   lu_byte flags;  /* 1<<p means tagmethod(p) is not present */
    563   lu_byte lsizenode;  /* log2 of size of `node' array */
    564   struct Table *metatable;
    565   TValue *array;  /* array part */
    566   Node *node;
    567   Node *lastfree;  /* any free position is before this position */
    568   GCObject *gclist;
    569   int sizearray;  /* size of `array' array */
    570 } Table;
    571 
    572 
    573 
    574 /*
    575 ** `module' operation for hashing (size is always a power of 2)
    576 */
    577 #define lmod(s,size) \
    578 	(check_exp((size&(size-1))==0, (cast(int, (s) & ((size)-1)))))
    579 
    580 
    581 #define twoto(x)	(1<<(x))
    582 #define sizenode(t)	(twoto((t)->lsizenode))
    583 
    584 
    585 /*
    586 ** (address of) a fixed nil value
    587 */
    588 #define luaO_nilobject		(&luaO_nilobject_)
    589 
    590 
    591 LUAI_DDEC const TValue luaO_nilobject_;
    592 
    593 
    594 LUAI_FUNC int luaO_int2fb (unsigned int x);
    595 LUAI_FUNC int luaO_fb2int (int x);
    596 LUAI_FUNC int luaO_ceillog2 (unsigned int x);
    597 LUAI_FUNC lua_Number luaO_arith (int op, lua_Number v1, lua_Number v2);
    598 LUAI_FUNC int luaO_str2d (const char *s, size_t len, lua_Number *result);
    599 LUAI_FUNC int luaO_hexavalue (int c);
    600 LUAI_FUNC const char *luaO_pushvfstring (lua_State *L, const char *fmt,
    601                                                        va_list argp);
    602 LUAI_FUNC const char *luaO_pushfstring (lua_State *L, const char *fmt, ...);
    603 LUAI_FUNC void luaO_chunkid (char *out, const char *source, size_t len);
    604 
    605 
    606 #endif
    607 
    608