xref: /freebsd/contrib/lua/src/lobject.h (revision e0c4386e7e71d93b0edc0c8fa156263fc4a8b0b6)
1 /*
2 ** $Id: lobject.h $
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 types for collectable non-values
21 */
22 #define LUA_TUPVAL	LUA_NUMTYPES  /* upvalues */
23 #define LUA_TPROTO	(LUA_NUMTYPES+1)  /* function prototypes */
24 #define LUA_TDEADKEY	(LUA_NUMTYPES+2)  /* removed keys in tables */
25 
26 
27 
28 /*
29 ** number of all possible types (including LUA_TNONE but excluding DEADKEY)
30 */
31 #define LUA_TOTALTYPES		(LUA_TPROTO + 2)
32 
33 
34 /*
35 ** tags for Tagged Values have the following use of bits:
36 ** bits 0-3: actual tag (a LUA_T* constant)
37 ** bits 4-5: variant bits
38 ** bit 6: whether value is collectable
39 */
40 
41 /* add variant bits to a type */
42 #define makevariant(t,v)	((t) | ((v) << 4))
43 
44 
45 
46 /*
47 ** Union of all Lua values
48 */
49 typedef union Value {
50   struct GCObject *gc;    /* collectable objects */
51   void *p;         /* light userdata */
52   lua_CFunction f; /* light C functions */
53   lua_Integer i;   /* integer numbers */
54   lua_Number n;    /* float numbers */
55   /* not used, but may avoid warnings for uninitialized value */
56   lu_byte ub;
57 } Value;
58 
59 
60 /*
61 ** Tagged Values. This is the basic representation of values in Lua:
62 ** an actual value plus a tag with its type.
63 */
64 
65 #define TValuefields	Value value_; lu_byte tt_
66 
67 typedef struct TValue {
68   TValuefields;
69 } TValue;
70 
71 
72 #define val_(o)		((o)->value_)
73 #define valraw(o)	(val_(o))
74 
75 
76 /* raw type tag of a TValue */
77 #define rawtt(o)	((o)->tt_)
78 
79 /* tag with no variants (bits 0-3) */
80 #define novariant(t)	((t) & 0x0F)
81 
82 /* type tag of a TValue (bits 0-3 for tags + variant bits 4-5) */
83 #define withvariant(t)	((t) & 0x3F)
84 #define ttypetag(o)	withvariant(rawtt(o))
85 
86 /* type of a TValue */
87 #define ttype(o)	(novariant(rawtt(o)))
88 
89 
90 /* Macros to test type */
91 #define checktag(o,t)		(rawtt(o) == (t))
92 #define checktype(o,t)		(ttype(o) == (t))
93 
94 
95 /* Macros for internal tests */
96 
97 /* collectable object has the same tag as the original value */
98 #define righttt(obj)		(ttypetag(obj) == gcvalue(obj)->tt)
99 
100 /*
101 ** Any value being manipulated by the program either is non
102 ** collectable, or the collectable object has the right tag
103 ** and it is not dead. The option 'L == NULL' allows other
104 ** macros using this one to be used where L is not available.
105 */
106 #define checkliveness(L,obj) \
107 	((void)L, lua_longassert(!iscollectable(obj) || \
108 		(righttt(obj) && (L == NULL || !isdead(G(L),gcvalue(obj))))))
109 
110 
111 /* Macros to set values */
112 
113 /* set a value's tag */
114 #define settt_(o,t)	((o)->tt_=(t))
115 
116 
117 /* main macro to copy values (from 'obj2' to 'obj1') */
118 #define setobj(L,obj1,obj2) \
119 	{ TValue *io1=(obj1); const TValue *io2=(obj2); \
120           io1->value_ = io2->value_; settt_(io1, io2->tt_); \
121 	  checkliveness(L,io1); lua_assert(!isnonstrictnil(io1)); }
122 
123 /*
124 ** Different types of assignments, according to source and destination.
125 ** (They are mostly equal now, but may be different in the future.)
126 */
127 
128 /* from stack to stack */
129 #define setobjs2s(L,o1,o2)	setobj(L,s2v(o1),s2v(o2))
130 /* to stack (not from same stack) */
131 #define setobj2s(L,o1,o2)	setobj(L,s2v(o1),o2)
132 /* from table to same table */
133 #define setobjt2t	setobj
134 /* to new object */
135 #define setobj2n	setobj
136 /* to table */
137 #define setobj2t	setobj
138 
139 
140 /*
141 ** Entries in a Lua stack. Field 'tbclist' forms a list of all
142 ** to-be-closed variables active in this stack. Dummy entries are
143 ** used when the distance between two tbc variables does not fit
144 ** in an unsigned short. They are represented by delta==0, and
145 ** their real delta is always the maximum value that fits in
146 ** that field.
147 */
148 typedef union StackValue {
149   TValue val;
150   struct {
151     TValuefields;
152     unsigned short delta;
153   } tbclist;
154 } StackValue;
155 
156 
157 /* index to stack elements */
158 typedef StackValue *StkId;
159 
160 
161 /*
162 ** When reallocating the stack, change all pointers to the stack into
163 ** proper offsets.
164 */
165 typedef union {
166   StkId p;  /* actual pointer */
167   ptrdiff_t offset;  /* used while the stack is being reallocated */
168 } StkIdRel;
169 
170 
171 /* convert a 'StackValue' to a 'TValue' */
172 #define s2v(o)	(&(o)->val)
173 
174 
175 
176 /*
177 ** {==================================================================
178 ** Nil
179 ** ===================================================================
180 */
181 
182 /* Standard nil */
183 #define LUA_VNIL	makevariant(LUA_TNIL, 0)
184 
185 /* Empty slot (which might be different from a slot containing nil) */
186 #define LUA_VEMPTY	makevariant(LUA_TNIL, 1)
187 
188 /* Value returned for a key not found in a table (absent key) */
189 #define LUA_VABSTKEY	makevariant(LUA_TNIL, 2)
190 
191 
192 /* macro to test for (any kind of) nil */
193 #define ttisnil(v)		checktype((v), LUA_TNIL)
194 
195 
196 /* macro to test for a standard nil */
197 #define ttisstrictnil(o)	checktag((o), LUA_VNIL)
198 
199 
200 #define setnilvalue(obj) settt_(obj, LUA_VNIL)
201 
202 
203 #define isabstkey(v)		checktag((v), LUA_VABSTKEY)
204 
205 
206 /*
207 ** macro to detect non-standard nils (used only in assertions)
208 */
209 #define isnonstrictnil(v)	(ttisnil(v) && !ttisstrictnil(v))
210 
211 
212 /*
213 ** By default, entries with any kind of nil are considered empty.
214 ** (In any definition, values associated with absent keys must also
215 ** be accepted as empty.)
216 */
217 #define isempty(v)		ttisnil(v)
218 
219 
220 /* macro defining a value corresponding to an absent key */
221 #define ABSTKEYCONSTANT		{NULL}, LUA_VABSTKEY
222 
223 
224 /* mark an entry as empty */
225 #define setempty(v)		settt_(v, LUA_VEMPTY)
226 
227 
228 
229 /* }================================================================== */
230 
231 
232 /*
233 ** {==================================================================
234 ** Booleans
235 ** ===================================================================
236 */
237 
238 
239 #define LUA_VFALSE	makevariant(LUA_TBOOLEAN, 0)
240 #define LUA_VTRUE	makevariant(LUA_TBOOLEAN, 1)
241 
242 #define ttisboolean(o)		checktype((o), LUA_TBOOLEAN)
243 #define ttisfalse(o)		checktag((o), LUA_VFALSE)
244 #define ttistrue(o)		checktag((o), LUA_VTRUE)
245 
246 
247 #define l_isfalse(o)	(ttisfalse(o) || ttisnil(o))
248 
249 
250 #define setbfvalue(obj)		settt_(obj, LUA_VFALSE)
251 #define setbtvalue(obj)		settt_(obj, LUA_VTRUE)
252 
253 /* }================================================================== */
254 
255 
256 /*
257 ** {==================================================================
258 ** Threads
259 ** ===================================================================
260 */
261 
262 #define LUA_VTHREAD		makevariant(LUA_TTHREAD, 0)
263 
264 #define ttisthread(o)		checktag((o), ctb(LUA_VTHREAD))
265 
266 #define thvalue(o)	check_exp(ttisthread(o), gco2th(val_(o).gc))
267 
268 #define setthvalue(L,obj,x) \
269   { TValue *io = (obj); lua_State *x_ = (x); \
270     val_(io).gc = obj2gco(x_); settt_(io, ctb(LUA_VTHREAD)); \
271     checkliveness(L,io); }
272 
273 #define setthvalue2s(L,o,t)	setthvalue(L,s2v(o),t)
274 
275 /* }================================================================== */
276 
277 
278 /*
279 ** {==================================================================
280 ** Collectable Objects
281 ** ===================================================================
282 */
283 
284 /*
285 ** Common Header for all collectable objects (in macro form, to be
286 ** included in other objects)
287 */
288 #define CommonHeader	struct GCObject *next; lu_byte tt; lu_byte marked
289 
290 
291 /* Common type for all collectable objects */
292 typedef struct GCObject {
293   CommonHeader;
294 } GCObject;
295 
296 
297 /* Bit mark for collectable types */
298 #define BIT_ISCOLLECTABLE	(1 << 6)
299 
300 #define iscollectable(o)	(rawtt(o) & BIT_ISCOLLECTABLE)
301 
302 /* mark a tag as collectable */
303 #define ctb(t)			((t) | BIT_ISCOLLECTABLE)
304 
305 #define gcvalue(o)	check_exp(iscollectable(o), val_(o).gc)
306 
307 #define gcvalueraw(v)	((v).gc)
308 
309 #define setgcovalue(L,obj,x) \
310   { TValue *io = (obj); GCObject *i_g=(x); \
311     val_(io).gc = i_g; settt_(io, ctb(i_g->tt)); }
312 
313 /* }================================================================== */
314 
315 
316 /*
317 ** {==================================================================
318 ** Numbers
319 ** ===================================================================
320 */
321 
322 /* Variant tags for numbers */
323 #define LUA_VNUMINT	makevariant(LUA_TNUMBER, 0)  /* integer numbers */
324 #define LUA_VNUMFLT	makevariant(LUA_TNUMBER, 1)  /* float numbers */
325 
326 #define ttisnumber(o)		checktype((o), LUA_TNUMBER)
327 #define ttisfloat(o)		checktag((o), LUA_VNUMFLT)
328 #define ttisinteger(o)		checktag((o), LUA_VNUMINT)
329 
330 #define nvalue(o)	check_exp(ttisnumber(o), \
331 	(ttisinteger(o) ? cast_num(ivalue(o)) : fltvalue(o)))
332 #define fltvalue(o)	check_exp(ttisfloat(o), val_(o).n)
333 #define ivalue(o)	check_exp(ttisinteger(o), val_(o).i)
334 
335 #define fltvalueraw(v)	((v).n)
336 #define ivalueraw(v)	((v).i)
337 
338 #define setfltvalue(obj,x) \
339   { TValue *io=(obj); val_(io).n=(x); settt_(io, LUA_VNUMFLT); }
340 
341 #define chgfltvalue(obj,x) \
342   { TValue *io=(obj); lua_assert(ttisfloat(io)); val_(io).n=(x); }
343 
344 #define setivalue(obj,x) \
345   { TValue *io=(obj); val_(io).i=(x); settt_(io, LUA_VNUMINT); }
346 
347 #define chgivalue(obj,x) \
348   { TValue *io=(obj); lua_assert(ttisinteger(io)); val_(io).i=(x); }
349 
350 /* }================================================================== */
351 
352 
353 /*
354 ** {==================================================================
355 ** Strings
356 ** ===================================================================
357 */
358 
359 /* Variant tags for strings */
360 #define LUA_VSHRSTR	makevariant(LUA_TSTRING, 0)  /* short strings */
361 #define LUA_VLNGSTR	makevariant(LUA_TSTRING, 1)  /* long strings */
362 
363 #define ttisstring(o)		checktype((o), LUA_TSTRING)
364 #define ttisshrstring(o)	checktag((o), ctb(LUA_VSHRSTR))
365 #define ttislngstring(o)	checktag((o), ctb(LUA_VLNGSTR))
366 
367 #define tsvalueraw(v)	(gco2ts((v).gc))
368 
369 #define tsvalue(o)	check_exp(ttisstring(o), gco2ts(val_(o).gc))
370 
371 #define setsvalue(L,obj,x) \
372   { TValue *io = (obj); TString *x_ = (x); \
373     val_(io).gc = obj2gco(x_); settt_(io, ctb(x_->tt)); \
374     checkliveness(L,io); }
375 
376 /* set a string to the stack */
377 #define setsvalue2s(L,o,s)	setsvalue(L,s2v(o),s)
378 
379 /* set a string to a new object */
380 #define setsvalue2n	setsvalue
381 
382 
383 /*
384 ** Header for a string value.
385 */
386 typedef struct TString {
387   CommonHeader;
388   lu_byte extra;  /* reserved words for short strings; "has hash" for longs */
389   lu_byte shrlen;  /* length for short strings */
390   unsigned int hash;
391   union {
392     size_t lnglen;  /* length for long strings */
393     struct TString *hnext;  /* linked list for hash table */
394   } u;
395   char contents[1];
396 } TString;
397 
398 
399 
400 /*
401 ** Get the actual string (array of bytes) from a 'TString'.
402 */
403 #define getstr(ts)  ((ts)->contents)
404 
405 
406 /* get the actual string (array of bytes) from a Lua value */
407 #define svalue(o)       getstr(tsvalue(o))
408 
409 /* get string length from 'TString *s' */
410 #define tsslen(s)	((s)->tt == LUA_VSHRSTR ? (s)->shrlen : (s)->u.lnglen)
411 
412 /* get string length from 'TValue *o' */
413 #define vslen(o)	tsslen(tsvalue(o))
414 
415 /* }================================================================== */
416 
417 
418 /*
419 ** {==================================================================
420 ** Userdata
421 ** ===================================================================
422 */
423 
424 
425 /*
426 ** Light userdata should be a variant of userdata, but for compatibility
427 ** reasons they are also different types.
428 */
429 #define LUA_VLIGHTUSERDATA	makevariant(LUA_TLIGHTUSERDATA, 0)
430 
431 #define LUA_VUSERDATA		makevariant(LUA_TUSERDATA, 0)
432 
433 #define ttislightuserdata(o)	checktag((o), LUA_VLIGHTUSERDATA)
434 #define ttisfulluserdata(o)	checktag((o), ctb(LUA_VUSERDATA))
435 
436 #define pvalue(o)	check_exp(ttislightuserdata(o), val_(o).p)
437 #define uvalue(o)	check_exp(ttisfulluserdata(o), gco2u(val_(o).gc))
438 
439 #define pvalueraw(v)	((v).p)
440 
441 #define setpvalue(obj,x) \
442   { TValue *io=(obj); val_(io).p=(x); settt_(io, LUA_VLIGHTUSERDATA); }
443 
444 #define setuvalue(L,obj,x) \
445   { TValue *io = (obj); Udata *x_ = (x); \
446     val_(io).gc = obj2gco(x_); settt_(io, ctb(LUA_VUSERDATA)); \
447     checkliveness(L,io); }
448 
449 
450 /* Ensures that addresses after this type are always fully aligned. */
451 typedef union UValue {
452   TValue uv;
453   LUAI_MAXALIGN;  /* ensures maximum alignment for udata bytes */
454 } UValue;
455 
456 
457 /*
458 ** Header for userdata with user values;
459 ** memory area follows the end of this structure.
460 */
461 typedef struct Udata {
462   CommonHeader;
463   unsigned short nuvalue;  /* number of user values */
464   size_t len;  /* number of bytes */
465   struct Table *metatable;
466   GCObject *gclist;
467   UValue uv[1];  /* user values */
468 } Udata;
469 
470 
471 /*
472 ** Header for userdata with no user values. These userdata do not need
473 ** to be gray during GC, and therefore do not need a 'gclist' field.
474 ** To simplify, the code always use 'Udata' for both kinds of userdata,
475 ** making sure it never accesses 'gclist' on userdata with no user values.
476 ** This structure here is used only to compute the correct size for
477 ** this representation. (The 'bindata' field in its end ensures correct
478 ** alignment for binary data following this header.)
479 */
480 typedef struct Udata0 {
481   CommonHeader;
482   unsigned short nuvalue;  /* number of user values */
483   size_t len;  /* number of bytes */
484   struct Table *metatable;
485   union {LUAI_MAXALIGN;} bindata;
486 } Udata0;
487 
488 
489 /* compute the offset of the memory area of a userdata */
490 #define udatamemoffset(nuv) \
491 	((nuv) == 0 ? offsetof(Udata0, bindata)  \
492                     : offsetof(Udata, uv) + (sizeof(UValue) * (nuv)))
493 
494 /* get the address of the memory block inside 'Udata' */
495 #define getudatamem(u)	(cast_charp(u) + udatamemoffset((u)->nuvalue))
496 
497 /* compute the size of a userdata */
498 #define sizeudata(nuv,nb)	(udatamemoffset(nuv) + (nb))
499 
500 /* }================================================================== */
501 
502 
503 /*
504 ** {==================================================================
505 ** Prototypes
506 ** ===================================================================
507 */
508 
509 #define LUA_VPROTO	makevariant(LUA_TPROTO, 0)
510 
511 
512 /*
513 ** Description of an upvalue for function prototypes
514 */
515 typedef struct Upvaldesc {
516   TString *name;  /* upvalue name (for debug information) */
517   lu_byte instack;  /* whether it is in stack (register) */
518   lu_byte idx;  /* index of upvalue (in stack or in outer function's list) */
519   lu_byte kind;  /* kind of corresponding variable */
520 } Upvaldesc;
521 
522 
523 /*
524 ** Description of a local variable for function prototypes
525 ** (used for debug information)
526 */
527 typedef struct LocVar {
528   TString *varname;
529   int startpc;  /* first point where variable is active */
530   int endpc;    /* first point where variable is dead */
531 } LocVar;
532 
533 
534 /*
535 ** Associates the absolute line source for a given instruction ('pc').
536 ** The array 'lineinfo' gives, for each instruction, the difference in
537 ** lines from the previous instruction. When that difference does not
538 ** fit into a byte, Lua saves the absolute line for that instruction.
539 ** (Lua also saves the absolute line periodically, to speed up the
540 ** computation of a line number: we can use binary search in the
541 ** absolute-line array, but we must traverse the 'lineinfo' array
542 ** linearly to compute a line.)
543 */
544 typedef struct AbsLineInfo {
545   int pc;
546   int line;
547 } AbsLineInfo;
548 
549 /*
550 ** Function Prototypes
551 */
552 typedef struct Proto {
553   CommonHeader;
554   lu_byte numparams;  /* number of fixed (named) parameters */
555   lu_byte is_vararg;
556   lu_byte maxstacksize;  /* number of registers needed by this function */
557   int sizeupvalues;  /* size of 'upvalues' */
558   int sizek;  /* size of 'k' */
559   int sizecode;
560   int sizelineinfo;
561   int sizep;  /* size of 'p' */
562   int sizelocvars;
563   int sizeabslineinfo;  /* size of 'abslineinfo' */
564   int linedefined;  /* debug information  */
565   int lastlinedefined;  /* debug information  */
566   TValue *k;  /* constants used by the function */
567   Instruction *code;  /* opcodes */
568   struct Proto **p;  /* functions defined inside the function */
569   Upvaldesc *upvalues;  /* upvalue information */
570   ls_byte *lineinfo;  /* information about source lines (debug information) */
571   AbsLineInfo *abslineinfo;  /* idem */
572   LocVar *locvars;  /* information about local variables (debug information) */
573   TString  *source;  /* used for debug information */
574   GCObject *gclist;
575 } Proto;
576 
577 /* }================================================================== */
578 
579 
580 /*
581 ** {==================================================================
582 ** Functions
583 ** ===================================================================
584 */
585 
586 #define LUA_VUPVAL	makevariant(LUA_TUPVAL, 0)
587 
588 
589 /* Variant tags for functions */
590 #define LUA_VLCL	makevariant(LUA_TFUNCTION, 0)  /* Lua closure */
591 #define LUA_VLCF	makevariant(LUA_TFUNCTION, 1)  /* light C function */
592 #define LUA_VCCL	makevariant(LUA_TFUNCTION, 2)  /* C closure */
593 
594 #define ttisfunction(o)		checktype(o, LUA_TFUNCTION)
595 #define ttisLclosure(o)		checktag((o), ctb(LUA_VLCL))
596 #define ttislcf(o)		checktag((o), LUA_VLCF)
597 #define ttisCclosure(o)		checktag((o), ctb(LUA_VCCL))
598 #define ttisclosure(o)         (ttisLclosure(o) || ttisCclosure(o))
599 
600 
601 #define isLfunction(o)	ttisLclosure(o)
602 
603 #define clvalue(o)	check_exp(ttisclosure(o), gco2cl(val_(o).gc))
604 #define clLvalue(o)	check_exp(ttisLclosure(o), gco2lcl(val_(o).gc))
605 #define fvalue(o)	check_exp(ttislcf(o), val_(o).f)
606 #define clCvalue(o)	check_exp(ttisCclosure(o), gco2ccl(val_(o).gc))
607 
608 #define fvalueraw(v)	((v).f)
609 
610 #define setclLvalue(L,obj,x) \
611   { TValue *io = (obj); LClosure *x_ = (x); \
612     val_(io).gc = obj2gco(x_); settt_(io, ctb(LUA_VLCL)); \
613     checkliveness(L,io); }
614 
615 #define setclLvalue2s(L,o,cl)	setclLvalue(L,s2v(o),cl)
616 
617 #define setfvalue(obj,x) \
618   { TValue *io=(obj); val_(io).f=(x); settt_(io, LUA_VLCF); }
619 
620 #define setclCvalue(L,obj,x) \
621   { TValue *io = (obj); CClosure *x_ = (x); \
622     val_(io).gc = obj2gco(x_); settt_(io, ctb(LUA_VCCL)); \
623     checkliveness(L,io); }
624 
625 
626 /*
627 ** Upvalues for Lua closures
628 */
629 typedef struct UpVal {
630   CommonHeader;
631   union {
632     TValue *p;  /* points to stack or to its own value */
633     ptrdiff_t offset;  /* used while the stack is being reallocated */
634   } v;
635   union {
636     struct {  /* (when open) */
637       struct UpVal *next;  /* linked list */
638       struct UpVal **previous;
639     } open;
640     TValue value;  /* the value (when closed) */
641   } u;
642 } UpVal;
643 
644 
645 
646 #define ClosureHeader \
647 	CommonHeader; lu_byte nupvalues; GCObject *gclist
648 
649 typedef struct CClosure {
650   ClosureHeader;
651   lua_CFunction f;
652   TValue upvalue[1];  /* list of upvalues */
653 } CClosure;
654 
655 
656 typedef struct LClosure {
657   ClosureHeader;
658   struct Proto *p;
659   UpVal *upvals[1];  /* list of upvalues */
660 } LClosure;
661 
662 
663 typedef union Closure {
664   CClosure c;
665   LClosure l;
666 } Closure;
667 
668 
669 #define getproto(o)	(clLvalue(o)->p)
670 
671 /* }================================================================== */
672 
673 
674 /*
675 ** {==================================================================
676 ** Tables
677 ** ===================================================================
678 */
679 
680 #define LUA_VTABLE	makevariant(LUA_TTABLE, 0)
681 
682 #define ttistable(o)		checktag((o), ctb(LUA_VTABLE))
683 
684 #define hvalue(o)	check_exp(ttistable(o), gco2t(val_(o).gc))
685 
686 #define sethvalue(L,obj,x) \
687   { TValue *io = (obj); Table *x_ = (x); \
688     val_(io).gc = obj2gco(x_); settt_(io, ctb(LUA_VTABLE)); \
689     checkliveness(L,io); }
690 
691 #define sethvalue2s(L,o,h)	sethvalue(L,s2v(o),h)
692 
693 
694 /*
695 ** Nodes for Hash tables: A pack of two TValue's (key-value pairs)
696 ** plus a 'next' field to link colliding entries. The distribution
697 ** of the key's fields ('key_tt' and 'key_val') not forming a proper
698 ** 'TValue' allows for a smaller size for 'Node' both in 4-byte
699 ** and 8-byte alignments.
700 */
701 typedef union Node {
702   struct NodeKey {
703     TValuefields;  /* fields for value */
704     lu_byte key_tt;  /* key type */
705     int next;  /* for chaining */
706     Value key_val;  /* key value */
707   } u;
708   TValue i_val;  /* direct access to node's value as a proper 'TValue' */
709 } Node;
710 
711 
712 /* copy a value into a key */
713 #define setnodekey(L,node,obj) \
714 	{ Node *n_=(node); const TValue *io_=(obj); \
715 	  n_->u.key_val = io_->value_; n_->u.key_tt = io_->tt_; \
716 	  checkliveness(L,io_); }
717 
718 
719 /* copy a value from a key */
720 #define getnodekey(L,obj,node) \
721 	{ TValue *io_=(obj); const Node *n_=(node); \
722 	  io_->value_ = n_->u.key_val; io_->tt_ = n_->u.key_tt; \
723 	  checkliveness(L,io_); }
724 
725 
726 /*
727 ** About 'alimit': if 'isrealasize(t)' is true, then 'alimit' is the
728 ** real size of 'array'. Otherwise, the real size of 'array' is the
729 ** smallest power of two not smaller than 'alimit' (or zero iff 'alimit'
730 ** is zero); 'alimit' is then used as a hint for #t.
731 */
732 
733 #define BITRAS		(1 << 7)
734 #define isrealasize(t)		(!((t)->flags & BITRAS))
735 #define setrealasize(t)		((t)->flags &= cast_byte(~BITRAS))
736 #define setnorealasize(t)	((t)->flags |= BITRAS)
737 
738 
739 typedef struct Table {
740   CommonHeader;
741   lu_byte flags;  /* 1<<p means tagmethod(p) is not present */
742   lu_byte lsizenode;  /* log2 of size of 'node' array */
743   unsigned int alimit;  /* "limit" of 'array' array */
744   TValue *array;  /* array part */
745   Node *node;
746   Node *lastfree;  /* any free position is before this position */
747   struct Table *metatable;
748   GCObject *gclist;
749 } Table;
750 
751 
752 /*
753 ** Macros to manipulate keys inserted in nodes
754 */
755 #define keytt(node)		((node)->u.key_tt)
756 #define keyval(node)		((node)->u.key_val)
757 
758 #define keyisnil(node)		(keytt(node) == LUA_TNIL)
759 #define keyisinteger(node)	(keytt(node) == LUA_VNUMINT)
760 #define keyival(node)		(keyval(node).i)
761 #define keyisshrstr(node)	(keytt(node) == ctb(LUA_VSHRSTR))
762 #define keystrval(node)		(gco2ts(keyval(node).gc))
763 
764 #define setnilkey(node)		(keytt(node) = LUA_TNIL)
765 
766 #define keyiscollectable(n)	(keytt(n) & BIT_ISCOLLECTABLE)
767 
768 #define gckey(n)	(keyval(n).gc)
769 #define gckeyN(n)	(keyiscollectable(n) ? gckey(n) : NULL)
770 
771 
772 /*
773 ** Dead keys in tables have the tag DEADKEY but keep their original
774 ** gcvalue. This distinguishes them from regular keys but allows them to
775 ** be found when searched in a special way. ('next' needs that to find
776 ** keys removed from a table during a traversal.)
777 */
778 #define setdeadkey(node)	(keytt(node) = LUA_TDEADKEY)
779 #define keyisdead(node)		(keytt(node) == LUA_TDEADKEY)
780 
781 /* }================================================================== */
782 
783 
784 
785 /*
786 ** 'module' operation for hashing (size is always a power of 2)
787 */
788 #define lmod(s,size) \
789 	(check_exp((size&(size-1))==0, (cast_int((s) & ((size)-1)))))
790 
791 
792 #define twoto(x)	(1<<(x))
793 #define sizenode(t)	(twoto((t)->lsizenode))
794 
795 
796 /* size of buffer for 'luaO_utf8esc' function */
797 #define UTF8BUFFSZ	8
798 
799 LUAI_FUNC int luaO_utf8esc (char *buff, unsigned long x);
800 LUAI_FUNC int luaO_ceillog2 (unsigned int x);
801 LUAI_FUNC int luaO_rawarith (lua_State *L, int op, const TValue *p1,
802                              const TValue *p2, TValue *res);
803 LUAI_FUNC void luaO_arith (lua_State *L, int op, const TValue *p1,
804                            const TValue *p2, StkId res);
805 LUAI_FUNC size_t luaO_str2num (const char *s, TValue *o);
806 LUAI_FUNC int luaO_hexavalue (int c);
807 LUAI_FUNC void luaO_tostring (lua_State *L, TValue *obj);
808 LUAI_FUNC const char *luaO_pushvfstring (lua_State *L, const char *fmt,
809                                                        va_list argp);
810 LUAI_FUNC const char *luaO_pushfstring (lua_State *L, const char *fmt, ...);
811 LUAI_FUNC void luaO_chunkid (char *out, const char *source, size_t srclen);
812 
813 
814 #endif
815 
816