xref: /freebsd/contrib/lua/src/lobject.h (revision a0409676120c1e558d0ade943019934e0f15118d)
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 } Value;
56 
57 
58 /*
59 ** Tagged Values. This is the basic representation of values in Lua:
60 ** an actual value plus a tag with its type.
61 */
62 
63 #define TValuefields	Value value_; lu_byte tt_
64 
65 typedef struct TValue {
66   TValuefields;
67 } TValue;
68 
69 
70 #define val_(o)		((o)->value_)
71 #define valraw(o)	(&val_(o))
72 
73 
74 /* raw type tag of a TValue */
75 #define rawtt(o)	((o)->tt_)
76 
77 /* tag with no variants (bits 0-3) */
78 #define novariant(t)	((t) & 0x0F)
79 
80 /* type tag of a TValue (bits 0-3 for tags + variant bits 4-5) */
81 #define withvariant(t)	((t) & 0x3F)
82 #define ttypetag(o)	withvariant(rawtt(o))
83 
84 /* type of a TValue */
85 #define ttype(o)	(novariant(rawtt(o)))
86 
87 
88 /* Macros to test type */
89 #define checktag(o,t)		(rawtt(o) == (t))
90 #define checktype(o,t)		(ttype(o) == (t))
91 
92 
93 /* Macros for internal tests */
94 
95 /* collectable object has the same tag as the original value */
96 #define righttt(obj)		(ttypetag(obj) == gcvalue(obj)->tt)
97 
98 /*
99 ** Any value being manipulated by the program either is non
100 ** collectable, or the collectable object has the right tag
101 ** and it is not dead. The option 'L == NULL' allows other
102 ** macros using this one to be used where L is not available.
103 */
104 #define checkliveness(L,obj) \
105 	((void)L, lua_longassert(!iscollectable(obj) || \
106 		(righttt(obj) && (L == NULL || !isdead(G(L),gcvalue(obj))))))
107 
108 
109 /* Macros to set values */
110 
111 /* set a value's tag */
112 #define settt_(o,t)	((o)->tt_=(t))
113 
114 
115 /* main macro to copy values (from 'obj1' to 'obj2') */
116 #define setobj(L,obj1,obj2) \
117 	{ TValue *io1=(obj1); const TValue *io2=(obj2); \
118           io1->value_ = io2->value_; settt_(io1, io2->tt_); \
119 	  checkliveness(L,io1); lua_assert(!isnonstrictnil(io1)); }
120 
121 /*
122 ** Different types of assignments, according to source and destination.
123 ** (They are mostly equal now, but may be different in the future.)
124 */
125 
126 /* from stack to stack */
127 #define setobjs2s(L,o1,o2)	setobj(L,s2v(o1),s2v(o2))
128 /* to stack (not from same stack) */
129 #define setobj2s(L,o1,o2)	setobj(L,s2v(o1),o2)
130 /* from table to same table */
131 #define setobjt2t	setobj
132 /* to new object */
133 #define setobj2n	setobj
134 /* to table */
135 #define setobj2t	setobj
136 
137 
138 /*
139 ** Entries in the Lua stack
140 */
141 typedef union StackValue {
142   TValue val;
143 } StackValue;
144 
145 
146 /* index to stack elements */
147 typedef StackValue *StkId;
148 
149 /* convert a 'StackValue' to a 'TValue' */
150 #define s2v(o)	(&(o)->val)
151 
152 
153 
154 /*
155 ** {==================================================================
156 ** Nil
157 ** ===================================================================
158 */
159 
160 /* Standard nil */
161 #define LUA_VNIL	makevariant(LUA_TNIL, 0)
162 
163 /* Empty slot (which might be different from a slot containing nil) */
164 #define LUA_VEMPTY	makevariant(LUA_TNIL, 1)
165 
166 /* Value returned for a key not found in a table (absent key) */
167 #define LUA_VABSTKEY	makevariant(LUA_TNIL, 2)
168 
169 
170 /* macro to test for (any kind of) nil */
171 #define ttisnil(v)		checktype((v), LUA_TNIL)
172 
173 
174 /* macro to test for a standard nil */
175 #define ttisstrictnil(o)	checktag((o), LUA_VNIL)
176 
177 
178 #define setnilvalue(obj) settt_(obj, LUA_VNIL)
179 
180 
181 #define isabstkey(v)		checktag((v), LUA_VABSTKEY)
182 
183 
184 /*
185 ** macro to detect non-standard nils (used only in assertions)
186 */
187 #define isnonstrictnil(v)	(ttisnil(v) && !ttisstrictnil(v))
188 
189 
190 /*
191 ** By default, entries with any kind of nil are considered empty.
192 ** (In any definition, values associated with absent keys must also
193 ** be accepted as empty.)
194 */
195 #define isempty(v)		ttisnil(v)
196 
197 
198 /* macro defining a value corresponding to an absent key */
199 #define ABSTKEYCONSTANT		{NULL}, LUA_VABSTKEY
200 
201 
202 /* mark an entry as empty */
203 #define setempty(v)		settt_(v, LUA_VEMPTY)
204 
205 
206 
207 /* }================================================================== */
208 
209 
210 /*
211 ** {==================================================================
212 ** Booleans
213 ** ===================================================================
214 */
215 
216 
217 #define LUA_VFALSE	makevariant(LUA_TBOOLEAN, 0)
218 #define LUA_VTRUE	makevariant(LUA_TBOOLEAN, 1)
219 
220 #define ttisboolean(o)		checktype((o), LUA_TBOOLEAN)
221 #define ttisfalse(o)		checktag((o), LUA_VFALSE)
222 #define ttistrue(o)		checktag((o), LUA_VTRUE)
223 
224 
225 #define l_isfalse(o)	(ttisfalse(o) || ttisnil(o))
226 
227 
228 #define setbfvalue(obj)		settt_(obj, LUA_VFALSE)
229 #define setbtvalue(obj)		settt_(obj, LUA_VTRUE)
230 
231 /* }================================================================== */
232 
233 
234 /*
235 ** {==================================================================
236 ** Threads
237 ** ===================================================================
238 */
239 
240 #define LUA_VTHREAD		makevariant(LUA_TTHREAD, 0)
241 
242 #define ttisthread(o)		checktag((o), ctb(LUA_VTHREAD))
243 
244 #define thvalue(o)	check_exp(ttisthread(o), gco2th(val_(o).gc))
245 
246 #define setthvalue(L,obj,x) \
247   { TValue *io = (obj); lua_State *x_ = (x); \
248     val_(io).gc = obj2gco(x_); settt_(io, ctb(LUA_VTHREAD)); \
249     checkliveness(L,io); }
250 
251 #define setthvalue2s(L,o,t)	setthvalue(L,s2v(o),t)
252 
253 /* }================================================================== */
254 
255 
256 /*
257 ** {==================================================================
258 ** Collectable Objects
259 ** ===================================================================
260 */
261 
262 /*
263 ** Common Header for all collectable objects (in macro form, to be
264 ** included in other objects)
265 */
266 #define CommonHeader	struct GCObject *next; lu_byte tt; lu_byte marked
267 
268 
269 /* Common type for all collectable objects */
270 typedef struct GCObject {
271   CommonHeader;
272 } GCObject;
273 
274 
275 /* Bit mark for collectable types */
276 #define BIT_ISCOLLECTABLE	(1 << 6)
277 
278 #define iscollectable(o)	(rawtt(o) & BIT_ISCOLLECTABLE)
279 
280 /* mark a tag as collectable */
281 #define ctb(t)			((t) | BIT_ISCOLLECTABLE)
282 
283 #define gcvalue(o)	check_exp(iscollectable(o), val_(o).gc)
284 
285 #define gcvalueraw(v)	((v).gc)
286 
287 #define setgcovalue(L,obj,x) \
288   { TValue *io = (obj); GCObject *i_g=(x); \
289     val_(io).gc = i_g; settt_(io, ctb(i_g->tt)); }
290 
291 /* }================================================================== */
292 
293 
294 /*
295 ** {==================================================================
296 ** Numbers
297 ** ===================================================================
298 */
299 
300 /* Variant tags for numbers */
301 #define LUA_VNUMINT	makevariant(LUA_TNUMBER, 0)  /* integer numbers */
302 #define LUA_VNUMFLT	makevariant(LUA_TNUMBER, 1)  /* float numbers */
303 
304 #define ttisnumber(o)		checktype((o), LUA_TNUMBER)
305 #define ttisfloat(o)		checktag((o), LUA_VNUMFLT)
306 #define ttisinteger(o)		checktag((o), LUA_VNUMINT)
307 
308 #define nvalue(o)	check_exp(ttisnumber(o), \
309 	(ttisinteger(o) ? cast_num(ivalue(o)) : fltvalue(o)))
310 #define fltvalue(o)	check_exp(ttisfloat(o), val_(o).n)
311 #define ivalue(o)	check_exp(ttisinteger(o), val_(o).i)
312 
313 #define fltvalueraw(v)	((v).n)
314 #define ivalueraw(v)	((v).i)
315 
316 #define setfltvalue(obj,x) \
317   { TValue *io=(obj); val_(io).n=(x); settt_(io, LUA_VNUMFLT); }
318 
319 #define chgfltvalue(obj,x) \
320   { TValue *io=(obj); lua_assert(ttisfloat(io)); val_(io).n=(x); }
321 
322 #define setivalue(obj,x) \
323   { TValue *io=(obj); val_(io).i=(x); settt_(io, LUA_VNUMINT); }
324 
325 #define chgivalue(obj,x) \
326   { TValue *io=(obj); lua_assert(ttisinteger(io)); val_(io).i=(x); }
327 
328 /* }================================================================== */
329 
330 
331 /*
332 ** {==================================================================
333 ** Strings
334 ** ===================================================================
335 */
336 
337 /* Variant tags for strings */
338 #define LUA_VSHRSTR	makevariant(LUA_TSTRING, 0)  /* short strings */
339 #define LUA_VLNGSTR	makevariant(LUA_TSTRING, 1)  /* long strings */
340 
341 #define ttisstring(o)		checktype((o), LUA_TSTRING)
342 #define ttisshrstring(o)	checktag((o), ctb(LUA_VSHRSTR))
343 #define ttislngstring(o)	checktag((o), ctb(LUA_VLNGSTR))
344 
345 #define tsvalueraw(v)	(gco2ts((v).gc))
346 
347 #define tsvalue(o)	check_exp(ttisstring(o), gco2ts(val_(o).gc))
348 
349 #define setsvalue(L,obj,x) \
350   { TValue *io = (obj); TString *x_ = (x); \
351     val_(io).gc = obj2gco(x_); settt_(io, ctb(x_->tt)); \
352     checkliveness(L,io); }
353 
354 /* set a string to the stack */
355 #define setsvalue2s(L,o,s)	setsvalue(L,s2v(o),s)
356 
357 /* set a string to a new object */
358 #define setsvalue2n	setsvalue
359 
360 
361 /*
362 ** Header for a string value.
363 */
364 typedef struct TString {
365   CommonHeader;
366   lu_byte extra;  /* reserved words for short strings; "has hash" for longs */
367   lu_byte shrlen;  /* length for short strings */
368   unsigned int hash;
369   union {
370     size_t lnglen;  /* length for long strings */
371     struct TString *hnext;  /* linked list for hash table */
372   } u;
373   char contents[1];
374 } TString;
375 
376 
377 
378 /*
379 ** Get the actual string (array of bytes) from a 'TString'.
380 */
381 #define getstr(ts)  ((ts)->contents)
382 
383 
384 /* get the actual string (array of bytes) from a Lua value */
385 #define svalue(o)       getstr(tsvalue(o))
386 
387 /* get string length from 'TString *s' */
388 #define tsslen(s)	((s)->tt == LUA_VSHRSTR ? (s)->shrlen : (s)->u.lnglen)
389 
390 /* get string length from 'TValue *o' */
391 #define vslen(o)	tsslen(tsvalue(o))
392 
393 /* }================================================================== */
394 
395 
396 /*
397 ** {==================================================================
398 ** Userdata
399 ** ===================================================================
400 */
401 
402 
403 /*
404 ** Light userdata should be a variant of userdata, but for compatibility
405 ** reasons they are also different types.
406 */
407 #define LUA_VLIGHTUSERDATA	makevariant(LUA_TLIGHTUSERDATA, 0)
408 
409 #define LUA_VUSERDATA		makevariant(LUA_TUSERDATA, 0)
410 
411 #define ttislightuserdata(o)	checktag((o), LUA_VLIGHTUSERDATA)
412 #define ttisfulluserdata(o)	checktag((o), ctb(LUA_VUSERDATA))
413 
414 #define pvalue(o)	check_exp(ttislightuserdata(o), val_(o).p)
415 #define uvalue(o)	check_exp(ttisfulluserdata(o), gco2u(val_(o).gc))
416 
417 #define pvalueraw(v)	((v).p)
418 
419 #define setpvalue(obj,x) \
420   { TValue *io=(obj); val_(io).p=(x); settt_(io, LUA_VLIGHTUSERDATA); }
421 
422 #define setuvalue(L,obj,x) \
423   { TValue *io = (obj); Udata *x_ = (x); \
424     val_(io).gc = obj2gco(x_); settt_(io, ctb(LUA_VUSERDATA)); \
425     checkliveness(L,io); }
426 
427 
428 /* Ensures that addresses after this type are always fully aligned. */
429 typedef union UValue {
430   TValue uv;
431   LUAI_MAXALIGN;  /* ensures maximum alignment for udata bytes */
432 } UValue;
433 
434 
435 /*
436 ** Header for userdata with user values;
437 ** memory area follows the end of this structure.
438 */
439 typedef struct Udata {
440   CommonHeader;
441   unsigned short nuvalue;  /* number of user values */
442   size_t len;  /* number of bytes */
443   struct Table *metatable;
444   GCObject *gclist;
445   UValue uv[1];  /* user values */
446 } Udata;
447 
448 
449 /*
450 ** Header for userdata with no user values. These userdata do not need
451 ** to be gray during GC, and therefore do not need a 'gclist' field.
452 ** To simplify, the code always use 'Udata' for both kinds of userdata,
453 ** making sure it never accesses 'gclist' on userdata with no user values.
454 ** This structure here is used only to compute the correct size for
455 ** this representation. (The 'bindata' field in its end ensures correct
456 ** alignment for binary data following this header.)
457 */
458 typedef struct Udata0 {
459   CommonHeader;
460   unsigned short nuvalue;  /* number of user values */
461   size_t len;  /* number of bytes */
462   struct Table *metatable;
463   union {LUAI_MAXALIGN;} bindata;
464 } Udata0;
465 
466 
467 /* compute the offset of the memory area of a userdata */
468 #define udatamemoffset(nuv) \
469 	((nuv) == 0 ? offsetof(Udata0, bindata)  \
470                     : offsetof(Udata, uv) + (sizeof(UValue) * (nuv)))
471 
472 /* get the address of the memory block inside 'Udata' */
473 #define getudatamem(u)	(cast_charp(u) + udatamemoffset((u)->nuvalue))
474 
475 /* compute the size of a userdata */
476 #define sizeudata(nuv,nb)	(udatamemoffset(nuv) + (nb))
477 
478 /* }================================================================== */
479 
480 
481 /*
482 ** {==================================================================
483 ** Prototypes
484 ** ===================================================================
485 */
486 
487 #define LUA_VPROTO	makevariant(LUA_TPROTO, 0)
488 
489 
490 /*
491 ** Description of an upvalue for function prototypes
492 */
493 typedef struct Upvaldesc {
494   TString *name;  /* upvalue name (for debug information) */
495   lu_byte instack;  /* whether it is in stack (register) */
496   lu_byte idx;  /* index of upvalue (in stack or in outer function's list) */
497   lu_byte kind;  /* kind of corresponding variable */
498 } Upvaldesc;
499 
500 
501 /*
502 ** Description of a local variable for function prototypes
503 ** (used for debug information)
504 */
505 typedef struct LocVar {
506   TString *varname;
507   int startpc;  /* first point where variable is active */
508   int endpc;    /* first point where variable is dead */
509 } LocVar;
510 
511 
512 /*
513 ** Associates the absolute line source for a given instruction ('pc').
514 ** The array 'lineinfo' gives, for each instruction, the difference in
515 ** lines from the previous instruction. When that difference does not
516 ** fit into a byte, Lua saves the absolute line for that instruction.
517 ** (Lua also saves the absolute line periodically, to speed up the
518 ** computation of a line number: we can use binary search in the
519 ** absolute-line array, but we must traverse the 'lineinfo' array
520 ** linearly to compute a line.)
521 */
522 typedef struct AbsLineInfo {
523   int pc;
524   int line;
525 } AbsLineInfo;
526 
527 /*
528 ** Function Prototypes
529 */
530 typedef struct Proto {
531   CommonHeader;
532   lu_byte numparams;  /* number of fixed (named) parameters */
533   lu_byte is_vararg;
534   lu_byte maxstacksize;  /* number of registers needed by this function */
535   int sizeupvalues;  /* size of 'upvalues' */
536   int sizek;  /* size of 'k' */
537   int sizecode;
538   int sizelineinfo;
539   int sizep;  /* size of 'p' */
540   int sizelocvars;
541   int sizeabslineinfo;  /* size of 'abslineinfo' */
542   int linedefined;  /* debug information  */
543   int lastlinedefined;  /* debug information  */
544   TValue *k;  /* constants used by the function */
545   Instruction *code;  /* opcodes */
546   struct Proto **p;  /* functions defined inside the function */
547   Upvaldesc *upvalues;  /* upvalue information */
548   ls_byte *lineinfo;  /* information about source lines (debug information) */
549   AbsLineInfo *abslineinfo;  /* idem */
550   LocVar *locvars;  /* information about local variables (debug information) */
551   TString  *source;  /* used for debug information */
552   GCObject *gclist;
553 } Proto;
554 
555 /* }================================================================== */
556 
557 
558 /*
559 ** {==================================================================
560 ** Functions
561 ** ===================================================================
562 */
563 
564 #define LUA_VUPVAL	makevariant(LUA_TUPVAL, 0)
565 
566 
567 /* Variant tags for functions */
568 #define LUA_VLCL	makevariant(LUA_TFUNCTION, 0)  /* Lua closure */
569 #define LUA_VLCF	makevariant(LUA_TFUNCTION, 1)  /* light C function */
570 #define LUA_VCCL	makevariant(LUA_TFUNCTION, 2)  /* C closure */
571 
572 #define ttisfunction(o)		checktype(o, LUA_TFUNCTION)
573 #define ttisclosure(o)		((rawtt(o) & 0x1F) == LUA_VLCL)
574 #define ttisLclosure(o)		checktag((o), ctb(LUA_VLCL))
575 #define ttislcf(o)		checktag((o), LUA_VLCF)
576 #define ttisCclosure(o)		checktag((o), ctb(LUA_VCCL))
577 
578 #define isLfunction(o)	ttisLclosure(o)
579 
580 #define clvalue(o)	check_exp(ttisclosure(o), gco2cl(val_(o).gc))
581 #define clLvalue(o)	check_exp(ttisLclosure(o), gco2lcl(val_(o).gc))
582 #define fvalue(o)	check_exp(ttislcf(o), val_(o).f)
583 #define clCvalue(o)	check_exp(ttisCclosure(o), gco2ccl(val_(o).gc))
584 
585 #define fvalueraw(v)	((v).f)
586 
587 #define setclLvalue(L,obj,x) \
588   { TValue *io = (obj); LClosure *x_ = (x); \
589     val_(io).gc = obj2gco(x_); settt_(io, ctb(LUA_VLCL)); \
590     checkliveness(L,io); }
591 
592 #define setclLvalue2s(L,o,cl)	setclLvalue(L,s2v(o),cl)
593 
594 #define setfvalue(obj,x) \
595   { TValue *io=(obj); val_(io).f=(x); settt_(io, LUA_VLCF); }
596 
597 #define setclCvalue(L,obj,x) \
598   { TValue *io = (obj); CClosure *x_ = (x); \
599     val_(io).gc = obj2gco(x_); settt_(io, ctb(LUA_VCCL)); \
600     checkliveness(L,io); }
601 
602 
603 /*
604 ** Upvalues for Lua closures
605 */
606 typedef struct UpVal {
607   CommonHeader;
608   lu_byte tbc;  /* true if it represents a to-be-closed variable */
609   TValue *v;  /* points to stack or to its own value */
610   union {
611     struct {  /* (when open) */
612       struct UpVal *next;  /* linked list */
613       struct UpVal **previous;
614     } open;
615     TValue value;  /* the value (when closed) */
616   } u;
617 } UpVal;
618 
619 
620 
621 #define ClosureHeader \
622 	CommonHeader; lu_byte nupvalues; GCObject *gclist
623 
624 typedef struct CClosure {
625   ClosureHeader;
626   lua_CFunction f;
627   TValue upvalue[1];  /* list of upvalues */
628 } CClosure;
629 
630 
631 typedef struct LClosure {
632   ClosureHeader;
633   struct Proto *p;
634   UpVal *upvals[1];  /* list of upvalues */
635 } LClosure;
636 
637 
638 typedef union Closure {
639   CClosure c;
640   LClosure l;
641 } Closure;
642 
643 
644 #define getproto(o)	(clLvalue(o)->p)
645 
646 /* }================================================================== */
647 
648 
649 /*
650 ** {==================================================================
651 ** Tables
652 ** ===================================================================
653 */
654 
655 #define LUA_VTABLE	makevariant(LUA_TTABLE, 0)
656 
657 #define ttistable(o)		checktag((o), ctb(LUA_VTABLE))
658 
659 #define hvalue(o)	check_exp(ttistable(o), gco2t(val_(o).gc))
660 
661 #define sethvalue(L,obj,x) \
662   { TValue *io = (obj); Table *x_ = (x); \
663     val_(io).gc = obj2gco(x_); settt_(io, ctb(LUA_VTABLE)); \
664     checkliveness(L,io); }
665 
666 #define sethvalue2s(L,o,h)	sethvalue(L,s2v(o),h)
667 
668 
669 /*
670 ** Nodes for Hash tables: A pack of two TValue's (key-value pairs)
671 ** plus a 'next' field to link colliding entries. The distribution
672 ** of the key's fields ('key_tt' and 'key_val') not forming a proper
673 ** 'TValue' allows for a smaller size for 'Node' both in 4-byte
674 ** and 8-byte alignments.
675 */
676 typedef union Node {
677   struct NodeKey {
678     TValuefields;  /* fields for value */
679     lu_byte key_tt;  /* key type */
680     int next;  /* for chaining */
681     Value key_val;  /* key value */
682   } u;
683   TValue i_val;  /* direct access to node's value as a proper 'TValue' */
684 } Node;
685 
686 
687 /* copy a value into a key */
688 #define setnodekey(L,node,obj) \
689 	{ Node *n_=(node); const TValue *io_=(obj); \
690 	  n_->u.key_val = io_->value_; n_->u.key_tt = io_->tt_; \
691 	  checkliveness(L,io_); }
692 
693 
694 /* copy a value from a key */
695 #define getnodekey(L,obj,node) \
696 	{ TValue *io_=(obj); const Node *n_=(node); \
697 	  io_->value_ = n_->u.key_val; io_->tt_ = n_->u.key_tt; \
698 	  checkliveness(L,io_); }
699 
700 
701 /*
702 ** About 'alimit': if 'isrealasize(t)' is true, then 'alimit' is the
703 ** real size of 'array'. Otherwise, the real size of 'array' is the
704 ** smallest power of two not smaller than 'alimit' (or zero iff 'alimit'
705 ** is zero); 'alimit' is then used as a hint for #t.
706 */
707 
708 #define BITRAS		(1 << 7)
709 #define isrealasize(t)		(!((t)->flags & BITRAS))
710 #define setrealasize(t)		((t)->flags &= cast_byte(~BITRAS))
711 #define setnorealasize(t)	((t)->flags |= BITRAS)
712 
713 
714 typedef struct Table {
715   CommonHeader;
716   lu_byte flags;  /* 1<<p means tagmethod(p) is not present */
717   lu_byte lsizenode;  /* log2 of size of 'node' array */
718   unsigned int alimit;  /* "limit" of 'array' array */
719   TValue *array;  /* array part */
720   Node *node;
721   Node *lastfree;  /* any free position is before this position */
722   struct Table *metatable;
723   GCObject *gclist;
724 } Table;
725 
726 
727 /*
728 ** Macros to manipulate keys inserted in nodes
729 */
730 #define keytt(node)		((node)->u.key_tt)
731 #define keyval(node)		((node)->u.key_val)
732 
733 #define keyisnil(node)		(keytt(node) == LUA_TNIL)
734 #define keyisinteger(node)	(keytt(node) == LUA_VNUMINT)
735 #define keyival(node)		(keyval(node).i)
736 #define keyisshrstr(node)	(keytt(node) == ctb(LUA_VSHRSTR))
737 #define keystrval(node)		(gco2ts(keyval(node).gc))
738 
739 #define setnilkey(node)		(keytt(node) = LUA_TNIL)
740 
741 #define keyiscollectable(n)	(keytt(n) & BIT_ISCOLLECTABLE)
742 
743 #define gckey(n)	(keyval(n).gc)
744 #define gckeyN(n)	(keyiscollectable(n) ? gckey(n) : NULL)
745 
746 
747 /*
748 ** Dead keys in tables have the tag DEADKEY but keep their original
749 ** gcvalue. This distinguishes them from regular keys but allows them to
750 ** be found when searched in a special way. ('next' needs that to find
751 ** keys removed from a table during a traversal.)
752 */
753 #define setdeadkey(node)	(keytt(node) = LUA_TDEADKEY)
754 #define keyisdead(node)		(keytt(node) == LUA_TDEADKEY)
755 
756 /* }================================================================== */
757 
758 
759 
760 /*
761 ** 'module' operation for hashing (size is always a power of 2)
762 */
763 #define lmod(s,size) \
764 	(check_exp((size&(size-1))==0, (cast_int((s) & ((size)-1)))))
765 
766 
767 #define twoto(x)	(1<<(x))
768 #define sizenode(t)	(twoto((t)->lsizenode))
769 
770 
771 /* size of buffer for 'luaO_utf8esc' function */
772 #define UTF8BUFFSZ	8
773 
774 LUAI_FUNC int luaO_utf8esc (char *buff, unsigned long x);
775 LUAI_FUNC int luaO_ceillog2 (unsigned int x);
776 LUAI_FUNC int luaO_rawarith (lua_State *L, int op, const TValue *p1,
777                              const TValue *p2, TValue *res);
778 LUAI_FUNC void luaO_arith (lua_State *L, int op, const TValue *p1,
779                            const TValue *p2, StkId res);
780 LUAI_FUNC size_t luaO_str2num (const char *s, TValue *o);
781 LUAI_FUNC int luaO_hexavalue (int c);
782 LUAI_FUNC void luaO_tostring (lua_State *L, TValue *obj);
783 LUAI_FUNC const char *luaO_pushvfstring (lua_State *L, const char *fmt,
784                                                        va_list argp);
785 LUAI_FUNC const char *luaO_pushfstring (lua_State *L, const char *fmt, ...);
786 LUAI_FUNC void luaO_chunkid (char *out, const char *source, size_t srclen);
787 
788 
789 #endif
790 
791