liblua/lapi.c

   1 /*
   2 ** $Id: lapi.c,v 2.171 2013/03/16 21:10:18 roberto Exp $
   3 ** Lua API
   4 ** See Copyright Notice in lua.h
   5 */
   6
   7
   8 #include <stdarg.h>
   9 #include <string.h>
  10
  11 #define lapi_c
  12 #define LUA_CORE
  13
  14 #include "lua.h"
  15
  16 #include "lapi.h"
  17 #include "ldebug.h"
  18 #include "ldo.h"
  19 #include "lfunc.h"
  20 #include "lgc.h"
  21 #include "lmem.h"
  22 #include "lobject.h"
  23 #include "lstate.h"
  24 #include "lstring.h"
  25 #include "ltable.h"
  26 #include "ltm.h"
  27 #include "lundump.h"
  28 #include "lvm.h"
  29
  30
  31
  32 const char lua_ident[] =
  33   "$LuaVersion: " LUA_COPYRIGHT " $"
  34   "$LuaAuthors: " LUA_AUTHORS " $";
  35
  36
  37 /* value at a non-valid index */
  38 #define NONVALIDVALUE           cast(TValue *, luaO_nilobject)
  39
  40 /* corresponding test */
  41 #define isvalid(o)      ((o) != luaO_nilobject)
  42
  43 /* test for pseudo index */
  44 #define ispseudo(i)             ((i) <= LUA_REGISTRYINDEX)
  45
  46 /* test for valid but not pseudo index */
  47 #define isstackindex(i, o)      (isvalid(o) && !ispseudo(i))
  48
  49 #define api_checkvalidindex(L, o)  api_check(L, isvalid(o), "invalid index")
  50
  51 #define api_checkstackindex(L, i, o)  \
  52         api_check(L, isstackindex(i, o), "index not in the stack")
  53
  54
  55 static TValue *index2addr (lua_State *L, int idx) {
  56   CallInfo *ci = L->ci;
  57   if (idx > 0) {
  58     TValue *o = ci->func + idx;
  59     api_check(L, idx <= ci->top - (ci->func + 1), "unacceptable index");
  60     if (o >= L->top) return NONVALIDVALUE;
  61     else return o;
  62   }
  63   else if (!ispseudo(idx)) {  /* negative index */
  64     api_check(L, idx != 0 && -idx <= L->top - (ci->func + 1), "invalid index");
  65     return L->top + idx;
  66   }
  67   else if (idx == LUA_REGISTRYINDEX)
  68     return &G(L)->l_registry;
  69   else {  /* upvalues */
  70     idx = LUA_REGISTRYINDEX - idx;
  71     api_check(L, idx <= MAXUPVAL + 1, "upvalue index too large");
  72     if (ttislcf(ci->func))  /* light C function? */
  73       return NONVALIDVALUE;  /* it has no upvalues */
  74     else {
  75       CClosure *func = clCvalue(ci->func);
  76       return (idx <= func->nupvalues) ? &func->upvalue[idx-1] : NONVALIDVALUE;
  77     }
  78   }
  79 }
  80
  81
  82 /*
  83 ** to be called by 'lua_checkstack' in protected mode, to grow stack
  84 ** capturing memory errors
  85 */
  86 static void growstack (lua_State *L, void *ud) {
  87   int size = *(int *)ud;
  88   luaD_growstack(L, size);
  89 }
  90
  91
  92 LUA_API int lua_checkstack (lua_State *L, int size) {
  93   int res;
  94   CallInfo *ci = L->ci;
  95   lua_lock(L);
  96   if (L->stack_last - L->top > size)  /* stack large enough? */
  97     res = 1;  /* yes; check is OK */
  98   else {  /* no; need to grow stack */
  99     int inuse = cast_int(L->top - L->stack) + EXTRA_STACK;
 100     if (inuse > LUAI_MAXSTACK - size)  /* can grow without overflow? */
 101       res = 0;  /* no */
 102     else  /* try to grow stack */
 103       res = (luaD_rawrunprotected(L, &growstack, &size) == LUA_OK);
 104   }
 105   if (res && ci->top < L->top + size)
 106     ci->top = L->top + size;  /* adjust frame top */
 107   lua_unlock(L);
 108   return res;
 109 }
 110
 111
 112 LUA_API void lua_xmove (lua_State *from, lua_State *to, int n) {
 113   int i;
 114   if (from == to) return;
 115   lua_lock(to);
 116   api_checknelems(from, n);
 117   api_check(from, G(from) == G(to), "moving among independent states");
 118   api_check(from, to->ci->top - to->top >= n, "not enough elements to move");
 119   from->top -= n;
 120   for (i = 0; i < n; i++) {
 121     setobj2s(to, to->top++, from->top + i);
 122   }
 123   lua_unlock(to);
 124 }
 125
 126
 127 LUA_API lua_CFunction lua_atpanic (lua_State *L, lua_CFunction panicf) {
 128   lua_CFunction old;
 129   lua_lock(L);
 130   old = G(L)->panic;
 131   G(L)->panic = panicf;
 132   lua_unlock(L);
 133   return old;
 134 }
 135
 136
 137 LUA_API const lua_Number *lua_version (lua_State *L) {
 138   static const lua_Number version = LUA_VERSION_NUM;
 139   if (L == NULL) return &version;
 140   else return G(L)->version;
 141 }
 142
 143
 144
 145 /*
 146 ** basic stack manipulation
 147 */
 148
 149
 150 /*
 151 ** convert an acceptable stack index into an absolute index
 152 */
 153 LUA_API int lua_absindex (lua_State *L, int idx) {
 154   return (idx > 0 || ispseudo(idx))
 155          ? idx
 156          : cast_int(L->top - L->ci->func + idx);
 157 }
 158
 159
 160 LUA_API int lua_gettop (lua_State *L) {
 161   return cast_int(L->top - (L->ci->func + 1));
 162 }
 163
 164
 165 LUA_API void lua_settop (lua_State *L, int idx) {
 166   StkId func = L->ci->func;
 167   lua_lock(L);
 168   if (idx >= 0) {
 169     api_check(L, idx <= L->stack_last - (func + 1), "new top too large");
 170     while (L->top < (func + 1) + idx)
 171       setnilvalue(L->top++);
 172     L->top = (func + 1) + idx;
 173   }
 174   else {
 175     api_check(L, -(idx+1) <= (L->top - (func + 1)), "invalid new top");
 176     L->top += idx+1;  /* `subtract' index (index is negative) */
 177   }
 178   lua_unlock(L);
 179 }
 180
 181
 182 LUA_API void lua_remove (lua_State *L, int idx) {
 183   StkId p;
 184   lua_lock(L);
 185   p = index2addr(L, idx);
 186   api_checkstackindex(L, idx, p);
 187   while (++p < L->top) setobjs2s(L, p-1, p);
 188   L->top--;
 189   lua_unlock(L);
 190 }
 191
 192
 193 LUA_API void lua_insert (lua_State *L, int idx) {
 194   StkId p;
 195   StkId q;
 196   lua_lock(L);
 197   p = index2addr(L, idx);
 198   api_checkstackindex(L, idx, p);
 199   for (q = L->top; q > p; q--)  /* use L->top as a temporary */
 200     setobjs2s(L, q, q - 1);
 201   setobjs2s(L, p, L->top);
 202   lua_unlock(L);
 203 }
 204
 205
 206 static void moveto (lua_State *L, TValue *fr, int idx) {
 207   TValue *to = index2addr(L, idx);
 208   api_checkvalidindex(L, to);
 209   setobj(L, to, fr);
 210   if (idx < LUA_REGISTRYINDEX)  /* function upvalue? */
 211     luaC_barrier(L, clCvalue(L->ci->func), fr);
 212   /* LUA_REGISTRYINDEX does not need gc barrier
 213      (collector revisits it before finishing collection) */
 214 }
 215
 216
 217 LUA_API void lua_replace (lua_State *L, int idx) {
 218   lua_lock(L);
 219   api_checknelems(L, 1);
 220   moveto(L, L->top - 1, idx);
 221   L->top--;
 222   lua_unlock(L);
 223 }
 224
 225
 226 LUA_API void lua_copy (lua_State *L, int fromidx, int toidx) {
 227   TValue *fr;
 228   lua_lock(L);
 229   fr = index2addr(L, fromidx);
 230   moveto(L, fr, toidx);
 231   lua_unlock(L);
 232 }
 233
 234
 235 LUA_API void lua_pushvalue (lua_State *L, int idx) {
 236   lua_lock(L);
 237   setobj2s(L, L->top, index2addr(L, idx));
 238   api_incr_top(L);
 239   lua_unlock(L);
 240 }
 241
 242
 243
 244 /*
 245 ** access functions (stack -> C)
 246 */
 247
 248
 249 LUA_API int lua_type (lua_State *L, int idx) {
 250   StkId o = index2addr(L, idx);
 251   return (isvalid(o) ? ttypenv(o) : LUA_TNONE);
 252 }
 253
 254
 255 LUA_API const char *lua_typename (lua_State *L, int t) {
 256   UNUSED(L);
 257   return ttypename(t);
 258 }
 259
 260
 261 LUA_API int lua_iscfunction (lua_State *L, int idx) {
 262   StkId o = index2addr(L, idx);
 263   return (ttislcf(o) || (ttisCclosure(o)));
 264 }
 265
 266
 267 LUA_API int lua_isnumber (lua_State *L, int idx) {
 268   TValue n;
 269   const TValue *o = index2addr(L, idx);
 270   return tonumber(o, &n);
 271 }
 272
 273
 274 LUA_API int lua_isstring (lua_State *L, int idx) {
 275   int t = lua_type(L, idx);
 276   return (t == LUA_TSTRING || t == LUA_TNUMBER);
 277 }
 278
 279
 280 LUA_API int lua_isuserdata (lua_State *L, int idx) {
 281   const TValue *o = index2addr(L, idx);
 282   return (ttisuserdata(o) || ttislightuserdata(o));
 283 }
 284
 285
 286 LUA_API int lua_rawequal (lua_State *L, int index1, int index2) {
 287   StkId o1 = index2addr(L, index1);
 288   StkId o2 = index2addr(L, index2);
 289   return (isvalid(o1) && isvalid(o2)) ? luaV_rawequalobj(o1, o2) : 0;
 290 }
 291
 292
 293 LUA_API void lua_arith (lua_State *L, int op) {
 294   StkId o1;  /* 1st operand */
 295   StkId o2;  /* 2nd operand */
 296   lua_lock(L);
 297   if (op != LUA_OPUNM) /* all other operations expect two operands */
 298     api_checknelems(L, 2);
 299   else {  /* for unary minus, add fake 2nd operand */
 300     api_checknelems(L, 1);
 301     setobjs2s(L, L->top, L->top - 1);
 302     L->top++;
 303   }
 304   o1 = L->top - 2;
 305   o2 = L->top - 1;
 306   if (ttisnumber(o1) && ttisnumber(o2)) {
 307     setnvalue(o1, luaO_arith(op, nvalue(o1), nvalue(o2)));
 308   }
 309   else
 310     luaV_arith(L, o1, o1, o2, cast(TMS, op - LUA_OPADD + TM_ADD));
 311   L->top--;
 312   lua_unlock(L);
 313 }
 314
 315
 316 LUA_API int lua_compare (lua_State *L, int index1, int index2, int op) {
 317   StkId o1, o2;
 318   int i = 0;
 319   lua_lock(L);  /* may call tag method */
 320   o1 = index2addr(L, index1);
 321   o2 = index2addr(L, index2);
 322   if (isvalid(o1) && isvalid(o2)) {
 323     switch (op) {
 324       case LUA_OPEQ: i = equalobj(L, o1, o2); break;
 325       case LUA_OPLT: i = luaV_lessthan(L, o1, o2); break;
 326       case LUA_OPLE: i = luaV_lessequal(L, o1, o2); break;
 327       default: api_check(L, 0, "invalid option");
 328     }
 329   }
 330   lua_unlock(L);
 331   return i;
 332 }
 333
 334
 335 LUA_API lua_Number lua_tonumberx (lua_State *L, int idx, int *isnum) {
 336   TValue n;
 337   const TValue *o = index2addr(L, idx);
 338   if (tonumber(o, &n)) {
 339     if (isnum) *isnum = 1;
 340     return nvalue(o);
 341   }
 342   else {
 343     if (isnum) *isnum = 0;
 344     return 0;
 345   }
 346 }
 347
 348
 349 LUA_API lua_Integer lua_tointegerx (lua_State *L, int idx, int *isnum) {
 350   TValue n;
 351   const TValue *o = index2addr(L, idx);
 352   if (tonumber(o, &n)) {
 353     lua_Integer res;
 354     lua_Number num = nvalue(o);
 355     lua_number2integer(res, num);
 356     if (isnum) *isnum = 1;
 357     return res;
 358   }
 359   else {
 360     if (isnum) *isnum = 0;
 361     return 0;
 362   }
 363 }
 364
 365
 366 LUA_API lua_Unsigned lua_tounsignedx (lua_State *L, int idx, int *isnum) {
 367   TValue n;
 368   const TValue *o = index2addr(L, idx);
 369   if (tonumber(o, &n)) {
 370     lua_Unsigned res;
 371     lua_Number num = nvalue(o);
 372     lua_number2unsigned(res, num);
 373     if (isnum) *isnum = 1;
 374     return res;
 375   }
 376   else {
 377     if (isnum) *isnum = 0;
 378     return 0;
 379   }
 380 }
 381
 382
 383 LUA_API int lua_toboolean (lua_State *L, int idx) {
 384   const TValue *o = index2addr(L, idx);
 385   return !l_isfalse(o);
 386 }
 387
 388
 389 LUA_API const char *lua_tolstring (lua_State *L, int idx, size_t *len) {
 390   StkId o = index2addr(L, idx);
 391   if (!ttisstring(o)) {
 392     lua_lock(L);  /* `luaV_tostring' may create a new string */
 393     if (!luaV_tostring(L, o)) {  /* conversion failed? */
 394       if (len != NULL) *len = 0;
 395       lua_unlock(L);
 396       return NULL;
 397     }
 398     luaC_checkGC(L);
 399     o = index2addr(L, idx);  /* previous call may reallocate the stack */
 400     lua_unlock(L);
 401   }
 402   if (len != NULL) *len = tsvalue(o)->len;
 403   return svalue(o);
 404 }
 405
 406
 407 LUA_API size_t lua_rawlen (lua_State *L, int idx) {
 408   StkId o = index2addr(L, idx);
 409   switch (ttypenv(o)) {
 410     case LUA_TSTRING: return tsvalue(o)->len;
 411     case LUA_TUSERDATA: return uvalue(o)->len;
 412     case LUA_TTABLE: return luaH_getn(hvalue(o));
 413     default: return 0;
 414   }
 415 }
 416
 417
 418 LUA_API lua_CFunction lua_tocfunction (lua_State *L, int idx) {
 419   StkId o = index2addr(L, idx);
 420   if (ttislcf(o)) return fvalue(o);
 421   else if (ttisCclosure(o))
 422     return clCvalue(o)->f;
 423   else return NULL;  /* not a C function */
 424 }
 425
 426
 427 LUA_API void *lua_touserdata (lua_State *L, int idx) {
 428   StkId o = index2addr(L, idx);
 429   switch (ttypenv(o)) {
 430     case LUA_TUSERDATA: return (rawuvalue(o) + 1);
 431     case LUA_TLIGHTUSERDATA: return pvalue(o);
 432     default: return NULL;
 433   }
 434 }
 435
 436
 437 LUA_API lua_State *lua_tothread (lua_State *L, int idx) {
 438   StkId o = index2addr(L, idx);
 439   return (!ttisthread(o)) ? NULL : thvalue(o);
 440 }
 441
 442
 443 LUA_API const void *lua_topointer (lua_State *L, int idx) {
 444   StkId o = index2addr(L, idx);
 445   switch (ttype(o)) {
 446     case LUA_TTABLE: return hvalue(o);
 447     case LUA_TLCL: return clLvalue(o);
 448     case LUA_TCCL: return clCvalue(o);
 449     case LUA_TLCF: return cast(void *, cast(size_t, fvalue(o)));
 450     case LUA_TTHREAD: return thvalue(o);
 451     case LUA_TUSERDATA:
 452     case LUA_TLIGHTUSERDATA:
 453       return lua_touserdata(L, idx);
 454     default: return NULL;
 455   }
 456 }
 457
 458
 459
 460 /*
 461 ** push functions (C -> stack)
 462 */
 463
 464
 465 LUA_API void lua_pushnil (lua_State *L) {
 466   lua_lock(L);
 467   setnilvalue(L->top);
 468   api_incr_top(L);
 469   lua_unlock(L);
 470 }
 471
 472
 473 LUA_API void lua_pushnumber (lua_State *L, lua_Number n) {
 474   lua_lock(L);
 475   setnvalue(L->top, n);
 476   luai_checknum(L, L->top,
 477     luaG_runerror(L, "C API - attempt to push a signaling NaN"));
 478   api_incr_top(L);
 479   lua_unlock(L);
 480 }
 481
 482
 483 LUA_API void lua_pushinteger (lua_State *L, lua_Integer n) {
 484   lua_lock(L);
 485   setnvalue(L->top, cast_num(n));
 486   api_incr_top(L);
 487   lua_unlock(L);
 488 }
 489
 490
 491 LUA_API void lua_pushunsigned (lua_State *L, lua_Unsigned u) {
 492   lua_Number n;
 493   lua_lock(L);
 494   n = lua_unsigned2number(u);
 495   setnvalue(L->top, n);
 496   api_incr_top(L);
 497   lua_unlock(L);
 498 }
 499
 500
 501 LUA_API const char *lua_pushlstring (lua_State *L, const char *s, size_t len) {
 502   TString *ts;
 503   lua_lock(L);
 504   luaC_checkGC(L);
 505   ts = luaS_newlstr(L, s, len);
 506   setsvalue2s(L, L->top, ts);
 507   api_incr_top(L);
 508   lua_unlock(L);
 509   return getstr(ts);
 510 }
 511
 512
 513 LUA_API const char *lua_pushstring (lua_State *L, const char *s) {
 514   if (s == NULL) {
 515     lua_pushnil(L);
 516     return NULL;
 517   }
 518   else {
 519     TString *ts;
 520     lua_lock(L);
 521     luaC_checkGC(L);
 522     ts = luaS_new(L, s);
 523     setsvalue2s(L, L->top, ts);
 524     api_incr_top(L);
 525     lua_unlock(L);
 526     return getstr(ts);
 527   }
 528 }
 529
 530
 531 LUA_API const char *lua_pushvfstring (lua_State *L, const char *fmt,
 532                                       va_list argp) {
 533   const char *ret;
 534   lua_lock(L);
 535   luaC_checkGC(L);
 536   ret = luaO_pushvfstring(L, fmt, argp);
 537   lua_unlock(L);
 538   return ret;
 539 }
 540
 541
 542 LUA_API const char *lua_pushfstring (lua_State *L, const char *fmt, ...) {
 543   const char *ret;
 544   va_list argp;
 545   lua_lock(L);
 546   luaC_checkGC(L);
 547   va_start(argp, fmt);
 548   ret = luaO_pushvfstring(L, fmt, argp);
 549   va_end(argp);
 550   lua_unlock(L);
 551   return ret;
 552 }
 553
 554
 555 LUA_API void lua_pushcclosure (lua_State *L, lua_CFunction fn, int n) {
 556   lua_lock(L);
 557   if (n == 0) {
 558     setfvalue(L->top, fn);
 559   }
 560   else {
 561     Closure *cl;
 562     api_checknelems(L, n);
 563     api_check(L, n <= MAXUPVAL, "upvalue index too large");
 564     luaC_checkGC(L);
 565     cl = luaF_newCclosure(L, n);
 566     cl->c.f = fn;
 567     L->top -= n;
 568     while (n--)
 569       setobj2n(L, &cl->c.upvalue[n], L->top + n);
 570     setclCvalue(L, L->top, cl);
 571   }
 572   api_incr_top(L);
 573   lua_unlock(L);
 574 }
 575
 576
 577 LUA_API void lua_pushboolean (lua_State *L, int b) {
 578   lua_lock(L);
 579   setbvalue(L->top, (b != 0));  /* ensure that true is 1 */
 580   api_incr_top(L);
 581   lua_unlock(L);
 582 }
 583
 584
 585 LUA_API void lua_pushlightuserdata (lua_State *L, void *p) {
 586   lua_lock(L);
 587   setpvalue(L->top, p);
 588   api_incr_top(L);
 589   lua_unlock(L);
 590 }
 591
 592
 593 LUA_API int lua_pushthread (lua_State *L) {
 594   lua_lock(L);
 595   setthvalue(L, L->top, L);
 596   api_incr_top(L);
 597   lua_unlock(L);
 598   return (G(L)->mainthread == L);
 599 }
 600
 601
 602
 603 /*
 604 ** get functions (Lua -> stack)
 605 */
 606
 607
 608 LUA_API void lua_getglobal (lua_State *L, const char *var) {
 609   Table *reg = hvalue(&G(L)->l_registry);
 610   const TValue *gt;  /* global table */
 611   lua_lock(L);
 612   gt = luaH_getint(reg, LUA_RIDX_GLOBALS);
 613   setsvalue2s(L, L->top++, luaS_new(L, var));
 614   luaV_gettable(L, gt, L->top - 1, L->top - 1);
 615   lua_unlock(L);
 616 }
 617
 618
 619 LUA_API void lua_gettable (lua_State *L, int idx) {
 620   StkId t;
 621   lua_lock(L);
 622   t = index2addr(L, idx);
 623   luaV_gettable(L, t, L->top - 1, L->top - 1);
 624   lua_unlock(L);
 625 }
 626
 627
 628 LUA_API void lua_getfield (lua_State *L, int idx, const char *k) {
 629   StkId t;
 630   lua_lock(L);
 631   t = index2addr(L, idx);
 632   setsvalue2s(L, L->top, luaS_new(L, k));
 633   api_incr_top(L);
 634   luaV_gettable(L, t, L->top - 1, L->top - 1);
 635   lua_unlock(L);
 636 }
 637
 638
 639 LUA_API void lua_rawget (lua_State *L, int idx) {
 640   StkId t;
 641   lua_lock(L);
 642   t = index2addr(L, idx);
 643   api_check(L, ttistable(t), "table expected");
 644   setobj2s(L, L->top - 1, luaH_get(hvalue(t), L->top - 1));
 645   lua_unlock(L);
 646 }
 647
 648
 649 LUA_API void lua_rawgeti (lua_State *L, int idx, int n) {
 650   StkId t;
 651   lua_lock(L);
 652   t = index2addr(L, idx);
 653   api_check(L, ttistable(t), "table expected");
 654   setobj2s(L, L->top, luaH_getint(hvalue(t), n));
 655   api_incr_top(L);
 656   lua_unlock(L);
 657 }
 658
 659
 660 LUA_API void lua_rawgetp (lua_State *L, int idx, const void *p) {
 661   StkId t;
 662   TValue k;
 663   lua_lock(L);
 664   t = index2addr(L, idx);
 665   api_check(L, ttistable(t), "table expected");
 666   setpvalue(&k, cast(void *, p));
 667   setobj2s(L, L->top, luaH_get(hvalue(t), &k));
 668   api_incr_top(L);
 669   lua_unlock(L);
 670 }
 671
 672
 673 LUA_API void lua_createtable (lua_State *L, int narray, int nrec) {
 674   Table *t;
 675   lua_lock(L);
 676   luaC_checkGC(L);
 677   t = luaH_new(L);
 678   sethvalue(L, L->top, t);
 679   api_incr_top(L);
 680   if (narray > 0 || nrec > 0)
 681     luaH_resize(L, t, narray, nrec);
 682   lua_unlock(L);
 683 }
 684
 685
 686 LUA_API int lua_getmetatable (lua_State *L, int objindex) {
 687   const TValue *obj;
 688   Table *mt = NULL;
 689   int res;
 690   lua_lock(L);
 691   obj = index2addr(L, objindex);
 692   switch (ttypenv(obj)) {
 693     case LUA_TTABLE:
 694       mt = hvalue(obj)->metatable;
 695       break;
 696     case LUA_TUSERDATA:
 697       mt = uvalue(obj)->metatable;
 698       break;
 699     default:
 700       mt = G(L)->mt[ttypenv(obj)];
 701       break;
 702   }
 703   if (mt == NULL)
 704     res = 0;
 705   else {
 706     sethvalue(L, L->top, mt);
 707     api_incr_top(L);
 708     res = 1;
 709   }
 710   lua_unlock(L);
 711   return res;
 712 }
 713
 714
 715 LUA_API void lua_getuservalue (lua_State *L, int idx) {
 716   StkId o;
 717   lua_lock(L);
 718   o = index2addr(L, idx);
 719   api_check(L, ttisuserdata(o), "userdata expected");
 720   if (uvalue(o)->env) {
 721     sethvalue(L, L->top, uvalue(o)->env);
 722   } else
 723     setnilvalue(L->top);
 724   api_incr_top(L);
 725   lua_unlock(L);
 726 }
 727
 728
 729 /*
 730 ** set functions (stack -> Lua)
 731 */
 732
 733
 734 LUA_API void lua_setglobal (lua_State *L, const char *var) {
 735   Table *reg = hvalue(&G(L)->l_registry);
 736   const TValue *gt;  /* global table */
 737   lua_lock(L);
 738   api_checknelems(L, 1);
 739   gt = luaH_getint(reg, LUA_RIDX_GLOBALS);
 740   setsvalue2s(L, L->top++, luaS_new(L, var));
 741   luaV_settable(L, gt, L->top - 1, L->top - 2);
 742   L->top -= 2;  /* pop value and key */
 743   lua_unlock(L);
 744 }
 745
 746
 747 LUA_API void lua_settable (lua_State *L, int idx) {
 748   StkId t;
 749   lua_lock(L);
 750   api_checknelems(L, 2);
 751   t = index2addr(L, idx);
 752   luaV_settable(L, t, L->top - 2, L->top - 1);
 753   L->top -= 2;  /* pop index and value */
 754   lua_unlock(L);
 755 }
 756
 757
 758 LUA_API void lua_setfield (lua_State *L, int idx, const char *k) {
 759   StkId t;
 760   lua_lock(L);
 761   api_checknelems(L, 1);
 762   t = index2addr(L, idx);
 763   setsvalue2s(L, L->top++, luaS_new(L, k));
 764   luaV_settable(L, t, L->top - 1, L->top - 2);
 765   L->top -= 2;  /* pop value and key */
 766   lua_unlock(L);
 767 }
 768
 769
 770 LUA_API void lua_rawset (lua_State *L, int idx) {
 771   StkId t;
 772   lua_lock(L);
 773   api_checknelems(L, 2);
 774   t = index2addr(L, idx);
 775   api_check(L, ttistable(t), "table expected");
 776   setobj2t(L, luaH_set(L, hvalue(t), L->top-2), L->top-1);
 777   invalidateTMcache(hvalue(t));
 778   luaC_barrierback(L, gcvalue(t), L->top-1);
 779   L->top -= 2;
 780   lua_unlock(L);
 781 }
 782
 783
 784 LUA_API void lua_rawseti (lua_State *L, int idx, int n) {
 785   StkId t;
 786   lua_lock(L);
 787   api_checknelems(L, 1);
 788   t = index2addr(L, idx);
 789   api_check(L, ttistable(t), "table expected");
 790   luaH_setint(L, hvalue(t), n, L->top - 1);
 791   luaC_barrierback(L, gcvalue(t), L->top-1);
 792   L->top--;
 793   lua_unlock(L);
 794 }
 795
 796
 797 LUA_API void lua_rawsetp (lua_State *L, int idx, const void *p) {
 798   StkId t;
 799   TValue k;
 800   lua_lock(L);
 801   api_checknelems(L, 1);
 802   t = index2addr(L, idx);
 803   api_check(L, ttistable(t), "table expected");
 804   setpvalue(&k, cast(void *, p));
 805   setobj2t(L, luaH_set(L, hvalue(t), &k), L->top - 1);
 806   luaC_barrierback(L, gcvalue(t), L->top - 1);
 807   L->top--;
 808   lua_unlock(L);
 809 }
 810
 811
 812 LUA_API int lua_setmetatable (lua_State *L, int objindex) {
 813   TValue *obj;
 814   Table *mt;
 815   lua_lock(L);
 816   api_checknelems(L, 1);
 817   obj = index2addr(L, objindex);
 818   if (ttisnil(L->top - 1))
 819     mt = NULL;
 820   else {
 821     api_check(L, ttistable(L->top - 1), "table expected");
 822     mt = hvalue(L->top - 1);
 823   }
 824   switch (ttypenv(obj)) {
 825     case LUA_TTABLE: {
 826       hvalue(obj)->metatable = mt;
 827       if (mt) {
 828         luaC_objbarrierback(L, gcvalue(obj), mt);
 829         luaC_checkfinalizer(L, gcvalue(obj), mt);
 830       }
 831       break;
 832     }
 833     case LUA_TUSERDATA: {
 834       uvalue(obj)->metatable = mt;
 835       if (mt) {
 836         luaC_objbarrier(L, rawuvalue(obj), mt);
 837         luaC_checkfinalizer(L, gcvalue(obj), mt);
 838       }
 839       break;
 840     }
 841     default: {
 842       G(L)->mt[ttypenv(obj)] = mt;
 843       break;
 844     }
 845   }
 846   L->top--;
 847   lua_unlock(L);
 848   return 1;
 849 }
 850
 851
 852 LUA_API void lua_setuservalue (lua_State *L, int idx) {
 853   StkId o;
 854   lua_lock(L);
 855   api_checknelems(L, 1);
 856   o = index2addr(L, idx);
 857   api_check(L, ttisuserdata(o), "userdata expected");
 858   if (ttisnil(L->top - 1))
 859     uvalue(o)->env = NULL;
 860   else {
 861     api_check(L, ttistable(L->top - 1), "table expected");
 862     uvalue(o)->env = hvalue(L->top - 1);
 863     luaC_objbarrier(L, gcvalue(o), hvalue(L->top - 1));
 864   }
 865   L->top--;
 866   lua_unlock(L);
 867 }
 868
 869
 870 /*
 871 ** `load' and `call' functions (run Lua code)
 872 */
 873
 874
 875 #define checkresults(L,na,nr) \
 876      api_check(L, (nr) == LUA_MULTRET || (L->ci->top - L->top >= (nr) - (na)), \
 877         "results from function overflow current stack size")
 878
 879
 880 LUA_API int lua_getctx (lua_State *L, int *ctx) {
 881   if (L->ci->callstatus & CIST_YIELDED) {
 882     if (ctx) *ctx = L->ci->u.c.ctx;
 883     return L->ci->u.c.status;
 884   }
 885   else return LUA_OK;
 886 }
 887
 888
 889 LUA_API void lua_callk (lua_State *L, int nargs, int nresults, int ctx,
 890                         lua_CFunction k) {
 891   StkId func;
 892   lua_lock(L);
 893   api_check(L, k == NULL || !isLua(L->ci),
 894     "cannot use continuations inside hooks");
 895   api_checknelems(L, nargs+1);
 896   api_check(L, L->status == LUA_OK, "cannot do calls on non-normal thread");
 897   checkresults(L, nargs, nresults);
 898   func = L->top - (nargs+1);
 899   if (k != NULL && L->nny == 0) {  /* need to prepare continuation? */
 900     L->ci->u.c.k = k;  /* save continuation */
 901     L->ci->u.c.ctx = ctx;  /* save context */
 902     luaD_call(L, func, nresults, 1);  /* do the call */
 903   }
 904   else  /* no continuation or no yieldable */
 905     luaD_call(L, func, nresults, 0);  /* just do the call */
 906   adjustresults(L, nresults);
 907   lua_unlock(L);
 908 }
 909
 910
 911
 912 /*
 913 ** Execute a protected call.
 914 */
 915 struct CallS {  /* data to `f_call' */
 916   StkId func;
 917   int nresults;
 918 };
 919
 920
 921 static void f_call (lua_State *L, void *ud) {
 922   struct CallS *c = cast(struct CallS *, ud);
 923   luaD_call(L, c->func, c->nresults, 0);
 924 }
 925
 926
 927
 928 LUA_API int lua_pcallk (lua_State *L, int nargs, int nresults, int errfunc,
 929                         int ctx, lua_CFunction k) {
 930   struct CallS c;
 931   int status;
 932   ptrdiff_t func;
 933   lua_lock(L);
 934   api_check(L, k == NULL || !isLua(L->ci),
 935     "cannot use continuations inside hooks");
 936   api_checknelems(L, nargs+1);
 937   api_check(L, L->status == LUA_OK, "cannot do calls on non-normal thread");
 938   checkresults(L, nargs, nresults);
 939   if (errfunc == 0)
 940     func = 0;
 941   else {
 942     StkId o = index2addr(L, errfunc);
 943     api_checkstackindex(L, errfunc, o);
 944     func = savestack(L, o);
 945   }
 946   c.func = L->top - (nargs+1);  /* function to be called */
 947   if (k == NULL || L->nny > 0) {  /* no continuation or no yieldable? */
 948     c.nresults = nresults;  /* do a 'conventional' protected call */
 949     status = luaD_pcall(L, f_call, &c, savestack(L, c.func), func);
 950   }
 951   else {  /* prepare continuation (call is already protected by 'resume') */
 952     CallInfo *ci = L->ci;
 953     ci->u.c.k = k;  /* save continuation */
 954     ci->u.c.ctx = ctx;  /* save context */
 955     /* save information for error recovery */
 956     ci->extra = savestack(L, c.func);
 957     ci->u.c.old_allowhook = L->allowhook;
 958     ci->u.c.old_errfunc = L->errfunc;
 959     L->errfunc = func;
 960     /* mark that function may do error recovery */
 961     ci->callstatus |= CIST_YPCALL;
 962     luaD_call(L, c.func, nresults, 1);  /* do the call */
 963     ci->callstatus &= ~CIST_YPCALL;
 964     L->errfunc = ci->u.c.old_errfunc;
 965     status = LUA_OK;  /* if it is here, there were no errors */
 966   }
 967   adjustresults(L, nresults);
 968   lua_unlock(L);
 969   return status;
 970 }
 971
 972
 973 LUA_API int lua_load (lua_State *L, lua_Reader reader, void *data,
 974                       const char *chunkname, const char *mode) {
 975   ZIO z;
 976   int status;
 977   lua_lock(L);
 978   if (!chunkname) chunkname = "?";
 979   luaZ_init(L, &z, reader, data);
 980   status = luaD_protectedparser(L, &z, chunkname, mode);
 981   if (status == LUA_OK) {  /* no errors? */
 982     LClosure *f = clLvalue(L->top - 1);  /* get newly created function */
 983     if (f->nupvalues == 1) {  /* does it have one upvalue? */
 984       /* get global table from registry */
 985       Table *reg = hvalue(&G(L)->l_registry);
 986       const TValue *gt = luaH_getint(reg, LUA_RIDX_GLOBALS);
 987       /* set global table as 1st upvalue of 'f' (may be LUA_ENV) */
 988       setobj(L, f->upvals[0]->v, gt);
 989       luaC_barrier(L, f->upvals[0], gt);
 990     }
 991   }
 992   lua_unlock(L);
 993   return status;
 994 }
 995
 996
 997 LUA_API int lua_dump (lua_State *L, lua_Writer writer, void *data) {
 998   int status;
 999   TValue *o;
1000   lua_lock(L);
1001   api_checknelems(L, 1);
1002   o = L->top - 1;
1003   if (isLfunction(o))
1004     status = luaU_dump(L, getproto(o), writer, data, 0);
1005   else
1006     status = 1;
1007   lua_unlock(L);
1008   return status;
1009 }
1010
1011
1012 LUA_API int lua_status (lua_State *L) {
1013   return L->status;
1014 }
1015
1016
1017 /*
1018 ** Garbage-collection function
1019 */
1020
1021 LUA_API int lua_gc (lua_State *L, int what, int data) {
1022   int res = 0;
1023   global_State *g;
1024   lua_lock(L);
1025   g = G(L);
1026   switch (what) {
1027     case LUA_GCSTOP: {
1028       g->gcrunning = 0;
1029       break;
1030     }
1031     case LUA_GCRESTART: {
1032       luaE_setdebt(g, 0);
1033       g->gcrunning = 1;
1034       break;
1035     }
1036     case LUA_GCCOLLECT: {
1037       luaC_fullgc(L, 0);
1038       break;
1039     }
1040     case LUA_GCCOUNT: {
1041       /* GC values are expressed in Kbytes: #bytes/2^10 */
1042       res = cast_int(gettotalbytes(g) >> 10);
1043       break;
1044     }
1045     case LUA_GCCOUNTB: {
1046       res = cast_int(gettotalbytes(g) & 0x3ff);
1047       break;
1048     }
1049     case LUA_GCSTEP: {
1050       if (g->gckind == KGC_GEN) {  /* generational mode? */
1051         res = (g->GCestimate == 0);  /* true if it will do major collection */
1052         luaC_forcestep(L);  /* do a single step */
1053       }
1054       else {
1055        lu_mem debt = cast(lu_mem, data) * 1024 - GCSTEPSIZE;
1056        if (g->gcrunning)
1057          debt += g->GCdebt;  /* include current debt */
1058        luaE_setdebt(g, debt);
1059        luaC_forcestep(L);
1060        if (g->gcstate == GCSpause)  /* end of cycle? */
1061          res = 1;  /* signal it */
1062       }
1063       break;
1064     }
1065     case LUA_GCSETPAUSE: {
1066       res = g->gcpause;
1067       g->gcpause = data;
1068       break;
1069     }
1070     case LUA_GCSETMAJORINC: {
1071       res = g->gcmajorinc;
1072       g->gcmajorinc = data;
1073       break;
1074     }
1075     case LUA_GCSETSTEPMUL: {
1076       res = g->gcstepmul;
1077       g->gcstepmul = data;
1078       break;
1079     }
1080     case LUA_GCISRUNNING: {
1081       res = g->gcrunning;
1082       break;
1083     }
1084     case LUA_GCGEN: {  /* change collector to generational mode */
1085       luaC_changemode(L, KGC_GEN);
1086       break;
1087     }
1088     case LUA_GCINC: {  /* change collector to incremental mode */
1089       luaC_changemode(L, KGC_NORMAL);
1090       break;
1091     }
1092     default: res = -1;  /* invalid option */
1093   }
1094   lua_unlock(L);
1095   return res;
1096 }
1097
1098
1099
1100 /*
1101 ** miscellaneous functions
1102 */
1103
1104
1105 LUA_API int lua_error (lua_State *L) {
1106   lua_lock(L);
1107   api_checknelems(L, 1);
1108   luaG_errormsg(L);
1109   /* code unreachable; will unlock when control actually leaves the kernel */
1110   return 0;  /* to avoid warnings */
1111 }
1112
1113
1114 LUA_API int lua_next (lua_State *L, int idx) {
1115   StkId t;
1116   int more;
1117   lua_lock(L);
1118   t = index2addr(L, idx);
1119   api_check(L, ttistable(t), "table expected");
1120   more = luaH_next(L, hvalue(t), L->top - 1);
1121   if (more) {
1122     api_incr_top(L);
1123   }
1124   else  /* no more elements */
1125     L->top -= 1;  /* remove key */
1126   lua_unlock(L);
1127   return more;
1128 }
1129
1130
1131 LUA_API void lua_concat (lua_State *L, int n) {
1132   lua_lock(L);
1133   api_checknelems(L, n);
1134   if (n >= 2) {
1135     luaC_checkGC(L);
1136     luaV_concat(L, n);
1137   }
1138   else if (n == 0) {  /* push empty string */
1139     setsvalue2s(L, L->top, luaS_newlstr(L, "", 0));
1140     api_incr_top(L);
1141   }
1142   /* else n == 1; nothing to do */
1143   lua_unlock(L);
1144 }
1145
1146
1147 LUA_API void lua_len (lua_State *L, int idx) {
1148   StkId t;
1149   lua_lock(L);
1150   t = index2addr(L, idx);
1151   luaV_objlen(L, L->top, t);
1152   api_incr_top(L);
1153   lua_unlock(L);
1154 }
1155
1156
1157 LUA_API lua_Alloc lua_getallocf (lua_State *L, void **ud) {
1158   lua_Alloc f;
1159   lua_lock(L);
1160   if (ud) *ud = G(L)->ud;
1161   f = G(L)->frealloc;
1162   lua_unlock(L);
1163   return f;
1164 }
1165
1166
1167 LUA_API void lua_setallocf (lua_State *L, lua_Alloc f, void *ud) {
1168   lua_lock(L);
1169   G(L)->ud = ud;
1170   G(L)->frealloc = f;
1171   lua_unlock(L);
1172 }
1173
1174
1175 LUA_API void *lua_newuserdata (lua_State *L, size_t size) {
1176   Udata *u;
1177   lua_lock(L);
1178   luaC_checkGC(L);
1179   u = luaS_newudata(L, size, NULL);
1180   setuvalue(L, L->top, u);
1181   api_incr_top(L);
1182   lua_unlock(L);
1183   return u + 1;
1184 }
1185
1186
1187
1188 static const char *aux_upvalue (StkId fi, int n, TValue **val,
1189                                 GCObject **owner) {
1190   switch (ttype(fi)) {
1191     case LUA_TCCL: {  /* C closure */
1192       CClosure *f = clCvalue(fi);
1193       if (!(1 <= n && n <= f->nupvalues)) return NULL;
1194       *val = &f->upvalue[n-1];
1195       if (owner) *owner = obj2gco(f);
1196       return "";
1197     }
1198     case LUA_TLCL: {  /* Lua closure */
1199       LClosure *f = clLvalue(fi);
1200       TString *name;
1201       Proto *p = f->p;
1202       if (!(1 <= n && n <= p->sizeupvalues)) return NULL;
1203       *val = f->upvals[n-1]->v;
1204       if (owner) *owner = obj2gco(f->upvals[n - 1]);
1205       name = p->upvalues[n-1].name;
1206       return (name == NULL) ? "" : getstr(name);
1207     }
1208     default: return NULL;  /* not a closure */
1209   }
1210 }
1211
1212
1213 LUA_API const char *lua_getupvalue (lua_State *L, int funcindex, int n) {
1214   const char *name;
1215   TValue *val = NULL;  /* to avoid warnings */
1216   lua_lock(L);
1217   name = aux_upvalue(index2addr(L, funcindex), n, &val, NULL);
1218   if (name) {
1219     setobj2s(L, L->top, val);
1220     api_incr_top(L);
1221   }
1222   lua_unlock(L);
1223   return name;
1224 }
1225
1226
1227 LUA_API const char *lua_setupvalue (lua_State *L, int funcindex, int n) {
1228   const char *name;
1229   TValue *val = NULL;  /* to avoid warnings */
1230   GCObject *owner = NULL;  /* to avoid warnings */
1231   StkId fi;
1232   lua_lock(L);
1233   fi = index2addr(L, funcindex);
1234   api_checknelems(L, 1);
1235   name = aux_upvalue(fi, n, &val, &owner);
1236   if (name) {
1237     L->top--;
1238     setobj(L, val, L->top);
1239     luaC_barrier(L, owner, L->top);
1240   }
1241   lua_unlock(L);
1242   return name;
1243 }
1244
1245
1246 static UpVal **getupvalref (lua_State *L, int fidx, int n, LClosure **pf) {
1247   LClosure *f;
1248   StkId fi = index2addr(L, fidx);
1249   api_check(L, ttisLclosure(fi), "Lua function expected");
1250   f = clLvalue(fi);
1251   api_check(L, (1 <= n && n <= f->p->sizeupvalues), "invalid upvalue index");
1252   if (pf) *pf = f;
1253   return &f->upvals[n - 1];  /* get its upvalue pointer */
1254 }
1255
1256
1257 LUA_API void *lua_upvalueid (lua_State *L, int fidx, int n) {
1258   StkId fi = index2addr(L, fidx);
1259   switch (ttype(fi)) {
1260     case LUA_TLCL: {  /* lua closure */
1261       return *getupvalref(L, fidx, n, NULL);
1262     }
1263     case LUA_TCCL: {  /* C closure */
1264       CClosure *f = clCvalue(fi);
1265       api_check(L, 1 <= n && n <= f->nupvalues, "invalid upvalue index");
1266       return &f->upvalue[n - 1];
1267     }
1268     default: {
1269       api_check(L, 0, "closure expected");
1270       return NULL;
1271     }
1272   }
1273 }
1274
1275
1276 LUA_API void lua_upvaluejoin (lua_State *L, int fidx1, int n1,
1277                                             int fidx2, int n2) {
1278   LClosure *f1;
1279   UpVal **up1 = getupvalref(L, fidx1, n1, &f1);
1280   UpVal **up2 = getupvalref(L, fidx2, n2, NULL);
1281   *up1 = *up2;
1282   luaC_objbarrier(L, f1, *up2);
1283 }
1284