lapi.cc - mudgangster - Tiny, scriptable MUD client

lapi.cc (31352B)
      1 /*
      2 ** $Id: lapi.c,v 2.259.1.2 2017/12/06 18:35:12 roberto Exp $
      3 ** Lua API
      4 ** See Copyright Notice in lua.h
      5 */
      6 
      7 #define lapi_c
      8 #define LUA_CORE
      9 
     10 #include "lprefix.h"
     11 
     12 
     13 #include <stdarg.h>
     14 #include <string.h>
     15 
     16 #include "lua.h"
     17 
     18 #include "lapi.h"
     19 #include "ldebug.h"
     20 #include "ldo.h"
     21 #include "lfunc.h"
     22 #include "lgc.h"
     23 #include "lmem.h"
     24 #include "lobject.h"
     25 #include "lstate.h"
     26 #include "lstring.h"
     27 #include "ltable.h"
     28 #include "ltm.h"
     29 #include "lundump.h"
     30 #include "lvm.h"
     31 
     32 
     33 
     34 const char lua_ident[] =
     35   "$LuaVersion: " LUA_COPYRIGHT " $"
     36   "$LuaAuthors: " LUA_AUTHORS " $";
     37 
     38 
     39 /* value at a non-valid index */
     40 #define NONVALIDVALUE		cast(TValue *, luaO_nilobject)
     41 
     42 /* corresponding test */
     43 #define isvalid(o)	((o) != luaO_nilobject)
     44 
     45 /* test for pseudo index */
     46 #define ispseudo(i)		((i) <= LUA_REGISTRYINDEX)
     47 
     48 /* test for upvalue */
     49 #define isupvalue(i)		((i) < LUA_REGISTRYINDEX)
     50 
     51 /* test for valid but not pseudo index */
     52 #define isstackindex(i, o)	(isvalid(o) && !ispseudo(i))
     53 
     54 #define api_checkvalidindex(l,o)  api_check(l, isvalid(o), "invalid index")
     55 
     56 #define api_checkstackindex(l, i, o)  \
     57 	api_check(l, isstackindex(i, o), "index not in the stack")
     58 
     59 
     60 static TValue *index2addr (lua_State *L, int idx) {
     61   CallInfo *ci = L->ci;
     62   if (idx > 0) {
     63     TValue *o = ci->func + idx;
     64     api_check(L, idx <= ci->top - (ci->func + 1), "unacceptable index");
     65     if (o >= L->top) return NONVALIDVALUE;
     66     else return o;
     67   }
     68   else if (!ispseudo(idx)) {  /* negative index */
     69     api_check(L, idx != 0 && -idx <= L->top - (ci->func + 1), "invalid index");
     70     return L->top + idx;
     71   }
     72   else if (idx == LUA_REGISTRYINDEX)
     73     return &G(L)->l_registry;
     74   else {  /* upvalues */
     75     idx = LUA_REGISTRYINDEX - idx;
     76     api_check(L, idx <= MAXUPVAL + 1, "upvalue index too large");
     77     if (ttislcf(ci->func))  /* light C function? */
     78       return NONVALIDVALUE;  /* it has no upvalues */
     79     else {
     80       CClosure *func = clCvalue(ci->func);
     81       return (idx <= func->nupvalues) ? &func->upvalue[idx-1] : NONVALIDVALUE;
     82     }
     83   }
     84 }
     85 
     86 
     87 /*
     88 ** to be called by 'lua_checkstack' in protected mode, to grow stack
     89 ** capturing memory errors
     90 */
     91 static void growstack (lua_State *L, void *ud) {
     92   int size = *(int *)ud;
     93   luaD_growstack(L, size);
     94 }
     95 
     96 
     97 LUA_API int lua_checkstack (lua_State *L, int n) {
     98   int res;
     99   CallInfo *ci = L->ci;
    100   lua_lock(L);
    101   api_check(L, n >= 0, "negative 'n'");
    102   if (L->stack_last - L->top > n)  /* stack large enough? */
    103     res = 1;  /* yes; check is OK */
    104   else {  /* no; need to grow stack */
    105     int inuse = cast_int(L->top - L->stack) + EXTRA_STACK;
    106     if (inuse > LUAI_MAXSTACK - n)  /* can grow without overflow? */
    107       res = 0;  /* no */
    108     else  /* try to grow stack */
    109       res = (luaD_rawrunprotected(L, &growstack, &n) == LUA_OK);
    110   }
    111   if (res && ci->top < L->top + n)
    112     ci->top = L->top + n;  /* adjust frame top */
    113   lua_unlock(L);
    114   return res;
    115 }
    116 
    117 
    118 LUA_API void lua_xmove (lua_State *from, lua_State *to, int n) {
    119   int i;
    120   if (from == to) return;
    121   lua_lock(to);
    122   api_checknelems(from, n);
    123   api_check(from, G(from) == G(to), "moving among independent states");
    124   api_check(from, to->ci->top - to->top >= n, "stack overflow");
    125   from->top -= n;
    126   for (i = 0; i < n; i++) {
    127     setobj2s(to, to->top, from->top + i);
    128     to->top++;  /* stack already checked by previous 'api_check' */
    129   }
    130   lua_unlock(to);
    131 }
    132 
    133 
    134 LUA_API lua_CFunction lua_atpanic (lua_State *L, lua_CFunction panicf) {
    135   lua_CFunction old;
    136   lua_lock(L);
    137   old = G(L)->panic;
    138   G(L)->panic = panicf;
    139   lua_unlock(L);
    140   return old;
    141 }
    142 
    143 
    144 LUA_API const lua_Number *lua_version (lua_State *L) {
    145   static const lua_Number version = LUA_VERSION_NUM;
    146   if (L == NULL) return &version;
    147   else return G(L)->version;
    148 }
    149 
    150 
    151 
    152 /*
    153 ** basic stack manipulation
    154 */
    155 
    156 
    157 /*
    158 ** convert an acceptable stack index into an absolute index
    159 */
    160 LUA_API int lua_absindex (lua_State *L, int idx) {
    161   return (idx > 0 || ispseudo(idx))
    162          ? idx
    163          : cast_int(L->top - L->ci->func) + idx;
    164 }
    165 
    166 
    167 LUA_API int lua_gettop (lua_State *L) {
    168   return cast_int(L->top - (L->ci->func + 1));
    169 }
    170 
    171 
    172 LUA_API void lua_settop (lua_State *L, int idx) {
    173   StkId func = L->ci->func;
    174   lua_lock(L);
    175   if (idx >= 0) {
    176     api_check(L, idx <= L->stack_last - (func + 1), "new top too large");
    177     while (L->top < (func + 1) + idx)
    178       setnilvalue(L->top++);
    179     L->top = (func + 1) + idx;
    180   }
    181   else {
    182     api_check(L, -(idx+1) <= (L->top - (func + 1)), "invalid new top");
    183     L->top += idx+1;  /* 'subtract' index (index is negative) */
    184   }
    185   lua_unlock(L);
    186 }
    187 
    188 
    189 /*
    190 ** Reverse the stack segment from 'from' to 'to'
    191 ** (auxiliary to 'lua_rotate')
    192 */
    193 static void reverse (lua_State *L, StkId from, StkId to) {
    194   for (; from < to; from++, to--) {
    195     TValue temp;
    196     setobj(L, &temp, from);
    197     setobjs2s(L, from, to);
    198     setobj2s(L, to, &temp);
    199   }
    200 }
    201 
    202 
    203 /*
    204 ** Let x = AB, where A is a prefix of length 'n'. Then,
    205 ** rotate x n == BA. But BA == (A^r . B^r)^r.
    206 */
    207 LUA_API void lua_rotate (lua_State *L, int idx, int n) {
    208   StkId p, t, m;
    209   lua_lock(L);
    210   t = L->top - 1;  /* end of stack segment being rotated */
    211   p = index2addr(L, idx);  /* start of segment */
    212   api_checkstackindex(L, idx, p);
    213   api_check(L, (n >= 0 ? n : -n) <= (t - p + 1), "invalid 'n'");
    214   m = (n >= 0 ? t - n : p - n - 1);  /* end of prefix */
    215   reverse(L, p, m);  /* reverse the prefix with length 'n' */
    216   reverse(L, m + 1, t);  /* reverse the suffix */
    217   reverse(L, p, t);  /* reverse the entire segment */
    218   lua_unlock(L);
    219 }
    220 
    221 
    222 LUA_API void lua_copy (lua_State *L, int fromidx, int toidx) {
    223   TValue *fr, *to;
    224   lua_lock(L);
    225   fr = index2addr(L, fromidx);
    226   to = index2addr(L, toidx);
    227   api_checkvalidindex(L, to);
    228   setobj(L, to, fr);
    229   if (isupvalue(toidx))  /* function upvalue? */
    230     luaC_barrier(L, clCvalue(L->ci->func), fr);
    231   /* LUA_REGISTRYINDEX does not need gc barrier
    232      (collector revisits it before finishing collection) */
    233   lua_unlock(L);
    234 }
    235 
    236 
    237 LUA_API void lua_pushvalue (lua_State *L, int idx) {
    238   lua_lock(L);
    239   setobj2s(L, L->top, index2addr(L, idx));
    240   api_incr_top(L);
    241   lua_unlock(L);
    242 }
    243 
    244 
    245 
    246 /*
    247 ** access functions (stack -> C)
    248 */
    249 
    250 
    251 LUA_API int lua_type (lua_State *L, int idx) {
    252   StkId o = index2addr(L, idx);
    253   return (isvalid(o) ? ttnov(o) : LUA_TNONE);
    254 }
    255 
    256 
    257 LUA_API const char *lua_typename (lua_State *L, int t) {
    258   UNUSED(L);
    259   api_check(L, LUA_TNONE <= t && t < LUA_NUMTAGS, "invalid tag");
    260   return ttypename(t);
    261 }
    262 
    263 
    264 LUA_API int lua_iscfunction (lua_State *L, int idx) {
    265   StkId o = index2addr(L, idx);
    266   return (ttislcf(o) || (ttisCclosure(o)));
    267 }
    268 
    269 
    270 LUA_API int lua_isinteger (lua_State *L, int idx) {
    271   StkId o = index2addr(L, idx);
    272   return ttisinteger(o);
    273 }
    274 
    275 
    276 LUA_API int lua_isnumber (lua_State *L, int idx) {
    277   lua_Number n;
    278   const TValue *o = index2addr(L, idx);
    279   return tonumber(o, &n);
    280 }
    281 
    282 
    283 LUA_API int lua_isstring (lua_State *L, int idx) {
    284   const TValue *o = index2addr(L, idx);
    285   return (ttisstring(o) || cvt2str(o));
    286 }
    287 
    288 
    289 LUA_API int lua_isuserdata (lua_State *L, int idx) {
    290   const TValue *o = index2addr(L, idx);
    291   return (ttisfulluserdata(o) || ttislightuserdata(o));
    292 }
    293 
    294 
    295 LUA_API int lua_rawequal (lua_State *L, int index1, int index2) {
    296   StkId o1 = index2addr(L, index1);
    297   StkId o2 = index2addr(L, index2);
    298   return (isvalid(o1) && isvalid(o2)) ? luaV_rawequalobj(o1, o2) : 0;
    299 }
    300 
    301 
    302 LUA_API void lua_arith (lua_State *L, int op) {
    303   lua_lock(L);
    304   if (op != LUA_OPUNM && op != LUA_OPBNOT)
    305     api_checknelems(L, 2);  /* all other operations expect two operands */
    306   else {  /* for unary operations, add fake 2nd operand */
    307     api_checknelems(L, 1);
    308     setobjs2s(L, L->top, L->top - 1);
    309     api_incr_top(L);
    310   }
    311   /* first operand at top - 2, second at top - 1; result go to top - 2 */
    312   luaO_arith(L, op, L->top - 2, L->top - 1, L->top - 2);
    313   L->top--;  /* remove second operand */
    314   lua_unlock(L);
    315 }
    316 
    317 
    318 LUA_API int lua_compare (lua_State *L, int index1, int index2, int op) {
    319   StkId o1, o2;
    320   int i = 0;
    321   lua_lock(L);  /* may call tag method */
    322   o1 = index2addr(L, index1);
    323   o2 = index2addr(L, index2);
    324   if (isvalid(o1) && isvalid(o2)) {
    325     switch (op) {
    326       case LUA_OPEQ: i = luaV_equalobj(L, o1, o2); break;
    327       case LUA_OPLT: i = luaV_lessthan(L, o1, o2); break;
    328       case LUA_OPLE: i = luaV_lessequal(L, o1, o2); break;
    329       default: api_check(L, 0, "invalid option");
    330     }
    331   }
    332   lua_unlock(L);
    333   return i;
    334 }
    335 
    336 
    337 LUA_API size_t lua_stringtonumber (lua_State *L, const char *s) {
    338   size_t sz = luaO_str2num(s, L->top);
    339   if (sz != 0)
    340     api_incr_top(L);
    341   return sz;
    342 }
    343 
    344 
    345 LUA_API lua_Number lua_tonumberx (lua_State *L, int idx, int *pisnum) {
    346   lua_Number n;
    347   const TValue *o = index2addr(L, idx);
    348   int isnum = tonumber(o, &n);
    349   if (!isnum)
    350     n = 0;  /* call to 'tonumber' may change 'n' even if it fails */
    351   if (pisnum) *pisnum = isnum;
    352   return n;
    353 }
    354 
    355 
    356 LUA_API lua_Integer lua_tointegerx (lua_State *L, int idx, int *pisnum) {
    357   lua_Integer res;
    358   const TValue *o = index2addr(L, idx);
    359   int isnum = tointeger(o, &res);
    360   if (!isnum)
    361     res = 0;  /* call to 'tointeger' may change 'n' even if it fails */
    362   if (pisnum) *pisnum = isnum;
    363   return res;
    364 }
    365 
    366 
    367 LUA_API int lua_toboolean (lua_State *L, int idx) {
    368   const TValue *o = index2addr(L, idx);
    369   return !l_isfalse(o);
    370 }
    371 
    372 
    373 LUA_API const char *lua_tolstring (lua_State *L, int idx, size_t *len) {
    374   StkId o = index2addr(L, idx);
    375   if (!ttisstring(o)) {
    376     if (!cvt2str(o)) {  /* not convertible? */
    377       if (len != NULL) *len = 0;
    378       return NULL;
    379     }
    380     lua_lock(L);  /* 'luaO_tostring' may create a new string */
    381     luaO_tostring(L, o);
    382     luaC_checkGC(L);
    383     o = index2addr(L, idx);  /* previous call may reallocate the stack */
    384     lua_unlock(L);
    385   }
    386   if (len != NULL)
    387     *len = vslen(o);
    388   return svalue(o);
    389 }
    390 
    391 
    392 LUA_API size_t lua_rawlen (lua_State *L, int idx) {
    393   StkId o = index2addr(L, idx);
    394   switch (ttype(o)) {
    395     case LUA_TSHRSTR: return tsvalue(o)->shrlen;
    396     case LUA_TLNGSTR: return tsvalue(o)->u.lnglen;
    397     case LUA_TUSERDATA: return uvalue(o)->len;
    398     case LUA_TTABLE: return luaH_getn(hvalue(o));
    399     default: return 0;
    400   }
    401 }
    402 
    403 
    404 LUA_API lua_CFunction lua_tocfunction (lua_State *L, int idx) {
    405   StkId o = index2addr(L, idx);
    406   if (ttislcf(o)) return fvalue(o);
    407   else if (ttisCclosure(o))
    408     return clCvalue(o)->f;
    409   else return NULL;  /* not a C function */
    410 }
    411 
    412 
    413 LUA_API void *lua_touserdata (lua_State *L, int idx) {
    414   StkId o = index2addr(L, idx);
    415   switch (ttnov(o)) {
    416     case LUA_TUSERDATA: return getudatamem(uvalue(o));
    417     case LUA_TLIGHTUSERDATA: return pvalue(o);
    418     default: return NULL;
    419   }
    420 }
    421 
    422 
    423 LUA_API lua_State *lua_tothread (lua_State *L, int idx) {
    424   StkId o = index2addr(L, idx);
    425   return (!ttisthread(o)) ? NULL : thvalue(o);
    426 }
    427 
    428 
    429 LUA_API const void *lua_topointer (lua_State *L, int idx) {
    430   StkId o = index2addr(L, idx);
    431   switch (ttype(o)) {
    432     case LUA_TTABLE: return hvalue(o);
    433     case LUA_TLCL: return clLvalue(o);
    434     case LUA_TCCL: return clCvalue(o);
    435     case LUA_TLCF: return cast(void *, cast(size_t, fvalue(o)));
    436     case LUA_TTHREAD: return thvalue(o);
    437     case LUA_TUSERDATA: return getudatamem(uvalue(o));
    438     case LUA_TLIGHTUSERDATA: return pvalue(o);
    439     default: return NULL;
    440   }
    441 }
    442 
    443 
    444 
    445 /*
    446 ** push functions (C -> stack)
    447 */
    448 
    449 
    450 LUA_API void lua_pushnil (lua_State *L) {
    451   lua_lock(L);
    452   setnilvalue(L->top);
    453   api_incr_top(L);
    454   lua_unlock(L);
    455 }
    456 
    457 
    458 LUA_API void lua_pushnumber (lua_State *L, lua_Number n) {
    459   lua_lock(L);
    460   setfltvalue(L->top, n);
    461   api_incr_top(L);
    462   lua_unlock(L);
    463 }
    464 
    465 
    466 LUA_API void lua_pushinteger (lua_State *L, lua_Integer n) {
    467   lua_lock(L);
    468   setivalue(L->top, n);
    469   api_incr_top(L);
    470   lua_unlock(L);
    471 }
    472 
    473 
    474 /*
    475 ** Pushes on the stack a string with given length. Avoid using 's' when
    476 ** 'len' == 0 (as 's' can be NULL in that case), due to later use of
    477 ** 'memcmp' and 'memcpy'.
    478 */
    479 LUA_API const char *lua_pushlstring (lua_State *L, const char *s, size_t len) {
    480   TString *ts;
    481   lua_lock(L);
    482   ts = (len == 0) ? luaS_new(L, "") : luaS_newlstr(L, s, len);
    483   setsvalue2s(L, L->top, ts);
    484   api_incr_top(L);
    485   luaC_checkGC(L);
    486   lua_unlock(L);
    487   return getstr(ts);
    488 }
    489 
    490 
    491 LUA_API const char *lua_pushstring (lua_State *L, const char *s) {
    492   lua_lock(L);
    493   if (s == NULL)
    494     setnilvalue(L->top);
    495   else {
    496     TString *ts;
    497     ts = luaS_new(L, s);
    498     setsvalue2s(L, L->top, ts);
    499     s = getstr(ts);  /* internal copy's address */
    500   }
    501   api_incr_top(L);
    502   luaC_checkGC(L);
    503   lua_unlock(L);
    504   return s;
    505 }
    506 
    507 
    508 LUA_API const char *lua_pushvfstring (lua_State *L, const char *fmt,
    509                                       va_list argp) {
    510   const char *ret;
    511   lua_lock(L);
    512   ret = luaO_pushvfstring(L, fmt, argp);
    513   luaC_checkGC(L);
    514   lua_unlock(L);
    515   return ret;
    516 }
    517 
    518 
    519 LUA_API const char *lua_pushfstring (lua_State *L, const char *fmt, ...) {
    520   const char *ret;
    521   va_list argp;
    522   lua_lock(L);
    523   va_start(argp, fmt);
    524   ret = luaO_pushvfstring(L, fmt, argp);
    525   va_end(argp);
    526   luaC_checkGC(L);
    527   lua_unlock(L);
    528   return ret;
    529 }
    530 
    531 
    532 LUA_API void lua_pushcclosure (lua_State *L, lua_CFunction fn, int n) {
    533   lua_lock(L);
    534   if (n == 0) {
    535     setfvalue(L->top, fn);
    536     api_incr_top(L);
    537   }
    538   else {
    539     CClosure *cl;
    540     api_checknelems(L, n);
    541     api_check(L, n <= MAXUPVAL, "upvalue index too large");
    542     cl = luaF_newCclosure(L, n);
    543     cl->f = fn;
    544     L->top -= n;
    545     while (n--) {
    546       setobj2n(L, &cl->upvalue[n], L->top + n);
    547       /* does not need barrier because closure is white */
    548     }
    549     setclCvalue(L, L->top, cl);
    550     api_incr_top(L);
    551     luaC_checkGC(L);
    552   }
    553   lua_unlock(L);
    554 }
    555 
    556 
    557 LUA_API void lua_pushboolean (lua_State *L, int b) {
    558   lua_lock(L);
    559   setbvalue(L->top, (b != 0));  /* ensure that true is 1 */
    560   api_incr_top(L);
    561   lua_unlock(L);
    562 }
    563 
    564 
    565 LUA_API void lua_pushlightuserdata (lua_State *L, void *p) {
    566   lua_lock(L);
    567   setpvalue(L->top, p);
    568   api_incr_top(L);
    569   lua_unlock(L);
    570 }
    571 
    572 
    573 LUA_API int lua_pushthread (lua_State *L) {
    574   lua_lock(L);
    575   setthvalue(L, L->top, L);
    576   api_incr_top(L);
    577   lua_unlock(L);
    578   return (G(L)->mainthread == L);
    579 }
    580 
    581 
    582 
    583 /*
    584 ** get functions (Lua -> stack)
    585 */
    586 
    587 
    588 static int auxgetstr (lua_State *L, const TValue *t, const char *k) {
    589   const TValue *slot;
    590   TString *str = luaS_new(L, k);
    591   if (luaV_fastget(L, t, str, slot, luaH_getstr)) {
    592     setobj2s(L, L->top, slot);
    593     api_incr_top(L);
    594   }
    595   else {
    596     setsvalue2s(L, L->top, str);
    597     api_incr_top(L);
    598     luaV_finishget(L, t, L->top - 1, L->top - 1, slot);
    599   }
    600   lua_unlock(L);
    601   return ttnov(L->top - 1);
    602 }
    603 
    604 
    605 LUA_API int lua_getglobal (lua_State *L, const char *name) {
    606   Table *reg = hvalue(&G(L)->l_registry);
    607   lua_lock(L);
    608   return auxgetstr(L, luaH_getint(reg, LUA_RIDX_GLOBALS), name);
    609 }
    610 
    611 
    612 LUA_API int lua_gettable (lua_State *L, int idx) {
    613   StkId t;
    614   lua_lock(L);
    615   t = index2addr(L, idx);
    616   luaV_gettable(L, t, L->top - 1, L->top - 1);
    617   lua_unlock(L);
    618   return ttnov(L->top - 1);
    619 }
    620 
    621 
    622 LUA_API int lua_getfield (lua_State *L, int idx, const char *k) {
    623   lua_lock(L);
    624   return auxgetstr(L, index2addr(L, idx), k);
    625 }
    626 
    627 
    628 LUA_API int lua_geti (lua_State *L, int idx, lua_Integer n) {
    629   StkId t;
    630   const TValue *slot;
    631   lua_lock(L);
    632   t = index2addr(L, idx);
    633   if (luaV_fastget(L, t, n, slot, luaH_getint)) {
    634     setobj2s(L, L->top, slot);
    635     api_incr_top(L);
    636   }
    637   else {
    638     setivalue(L->top, n);
    639     api_incr_top(L);
    640     luaV_finishget(L, t, L->top - 1, L->top - 1, slot);
    641   }
    642   lua_unlock(L);
    643   return ttnov(L->top - 1);
    644 }
    645 
    646 
    647 LUA_API int lua_rawget (lua_State *L, int idx) {
    648   StkId t;
    649   lua_lock(L);
    650   t = index2addr(L, idx);
    651   api_check(L, ttistable(t), "table expected");
    652   setobj2s(L, L->top - 1, luaH_get(hvalue(t), L->top - 1));
    653   lua_unlock(L);
    654   return ttnov(L->top - 1);
    655 }
    656 
    657 
    658 LUA_API int lua_rawgeti (lua_State *L, int idx, lua_Integer n) {
    659   StkId t;
    660   lua_lock(L);
    661   t = index2addr(L, idx);
    662   api_check(L, ttistable(t), "table expected");
    663   setobj2s(L, L->top, luaH_getint(hvalue(t), n));
    664   api_incr_top(L);
    665   lua_unlock(L);
    666   return ttnov(L->top - 1);
    667 }
    668 
    669 
    670 LUA_API int lua_rawgetp (lua_State *L, int idx, const void *p) {
    671   StkId t;
    672   TValue k;
    673   lua_lock(L);
    674   t = index2addr(L, idx);
    675   api_check(L, ttistable(t), "table expected");
    676   setpvalue(&k, cast(void *, p));
    677   setobj2s(L, L->top, luaH_get(hvalue(t), &k));
    678   api_incr_top(L);
    679   lua_unlock(L);
    680   return ttnov(L->top - 1);
    681 }
    682 
    683 
    684 LUA_API void lua_createtable (lua_State *L, int narray, int nrec) {
    685   Table *t;
    686   lua_lock(L);
    687   t = luaH_new(L);
    688   sethvalue(L, L->top, t);
    689   api_incr_top(L);
    690   if (narray > 0 || nrec > 0)
    691     luaH_resize(L, t, narray, nrec);
    692   luaC_checkGC(L);
    693   lua_unlock(L);
    694 }
    695 
    696 
    697 LUA_API int lua_getmetatable (lua_State *L, int objindex) {
    698   const TValue *obj;
    699   Table *mt;
    700   int res = 0;
    701   lua_lock(L);
    702   obj = index2addr(L, objindex);
    703   switch (ttnov(obj)) {
    704     case LUA_TTABLE:
    705       mt = hvalue(obj)->metatable;
    706       break;
    707     case LUA_TUSERDATA:
    708       mt = uvalue(obj)->metatable;
    709       break;
    710     default:
    711       mt = G(L)->mt[ttnov(obj)];
    712       break;
    713   }
    714   if (mt != NULL) {
    715     sethvalue(L, L->top, mt);
    716     api_incr_top(L);
    717     res = 1;
    718   }
    719   lua_unlock(L);
    720   return res;
    721 }
    722 
    723 
    724 LUA_API int lua_getuservalue (lua_State *L, int idx) {
    725   StkId o;
    726   lua_lock(L);
    727   o = index2addr(L, idx);
    728   api_check(L, ttisfulluserdata(o), "full userdata expected");
    729   getuservalue(L, uvalue(o), L->top);
    730   api_incr_top(L);
    731   lua_unlock(L);
    732   return ttnov(L->top - 1);
    733 }
    734 
    735 
    736 /*
    737 ** set functions (stack -> Lua)
    738 */
    739 
    740 /*
    741 ** t[k] = value at the top of the stack (where 'k' is a string)
    742 */
    743 static void auxsetstr (lua_State *L, const TValue *t, const char *k) {
    744   const TValue *slot;
    745   TString *str = luaS_new(L, k);
    746   api_checknelems(L, 1);
    747   if (luaV_fastset(L, t, str, slot, luaH_getstr, L->top - 1))
    748     L->top--;  /* pop value */
    749   else {
    750     setsvalue2s(L, L->top, str);  /* push 'str' (to make it a TValue) */
    751     api_incr_top(L);
    752     luaV_finishset(L, t, L->top - 1, L->top - 2, slot);
    753     L->top -= 2;  /* pop value and key */
    754   }
    755   lua_unlock(L);  /* lock done by caller */
    756 }
    757 
    758 
    759 LUA_API void lua_setglobal (lua_State *L, const char *name) {
    760   Table *reg = hvalue(&G(L)->l_registry);
    761   lua_lock(L);  /* unlock done in 'auxsetstr' */
    762   auxsetstr(L, luaH_getint(reg, LUA_RIDX_GLOBALS), name);
    763 }
    764 
    765 
    766 LUA_API void lua_settable (lua_State *L, int idx) {
    767   StkId t;
    768   lua_lock(L);
    769   api_checknelems(L, 2);
    770   t = index2addr(L, idx);
    771   luaV_settable(L, t, L->top - 2, L->top - 1);
    772   L->top -= 2;  /* pop index and value */
    773   lua_unlock(L);
    774 }
    775 
    776 
    777 LUA_API void lua_setfield (lua_State *L, int idx, const char *k) {
    778   lua_lock(L);  /* unlock done in 'auxsetstr' */
    779   auxsetstr(L, index2addr(L, idx), k);
    780 }
    781 
    782 
    783 LUA_API void lua_seti (lua_State *L, int idx, lua_Integer n) {
    784   StkId t;
    785   const TValue *slot;
    786   lua_lock(L);
    787   api_checknelems(L, 1);
    788   t = index2addr(L, idx);
    789   if (luaV_fastset(L, t, n, slot, luaH_getint, L->top - 1))
    790     L->top--;  /* pop value */
    791   else {
    792     setivalue(L->top, n);
    793     api_incr_top(L);
    794     luaV_finishset(L, t, L->top - 1, L->top - 2, slot);
    795     L->top -= 2;  /* pop value and key */
    796   }
    797   lua_unlock(L);
    798 }
    799 
    800 
    801 LUA_API void lua_rawset (lua_State *L, int idx) {
    802   StkId o;
    803   TValue *slot;
    804   lua_lock(L);
    805   api_checknelems(L, 2);
    806   o = index2addr(L, idx);
    807   api_check(L, ttistable(o), "table expected");
    808   slot = luaH_set(L, hvalue(o), L->top - 2);
    809   setobj2t(L, slot, L->top - 1);
    810   invalidateTMcache(hvalue(o));
    811   luaC_barrierback(L, hvalue(o), L->top-1);
    812   L->top -= 2;
    813   lua_unlock(L);
    814 }
    815 
    816 
    817 LUA_API void lua_rawseti (lua_State *L, int idx, lua_Integer n) {
    818   StkId o;
    819   lua_lock(L);
    820   api_checknelems(L, 1);
    821   o = index2addr(L, idx);
    822   api_check(L, ttistable(o), "table expected");
    823   luaH_setint(L, hvalue(o), n, L->top - 1);
    824   luaC_barrierback(L, hvalue(o), L->top-1);
    825   L->top--;
    826   lua_unlock(L);
    827 }
    828 
    829 
    830 LUA_API void lua_rawsetp (lua_State *L, int idx, const void *p) {
    831   StkId o;
    832   TValue k, *slot;
    833   lua_lock(L);
    834   api_checknelems(L, 1);
    835   o = index2addr(L, idx);
    836   api_check(L, ttistable(o), "table expected");
    837   setpvalue(&k, cast(void *, p));
    838   slot = luaH_set(L, hvalue(o), &k);
    839   setobj2t(L, slot, L->top - 1);
    840   luaC_barrierback(L, hvalue(o), L->top - 1);
    841   L->top--;
    842   lua_unlock(L);
    843 }
    844 
    845 
    846 LUA_API int lua_setmetatable (lua_State *L, int objindex) {
    847   TValue *obj;
    848   Table *mt;
    849   lua_lock(L);
    850   api_checknelems(L, 1);
    851   obj = index2addr(L, objindex);
    852   if (ttisnil(L->top - 1))
    853     mt = NULL;
    854   else {
    855     api_check(L, ttistable(L->top - 1), "table expected");
    856     mt = hvalue(L->top - 1);
    857   }
    858   switch (ttnov(obj)) {
    859     case LUA_TTABLE: {
    860       hvalue(obj)->metatable = mt;
    861       if (mt) {
    862         luaC_objbarrier(L, gcvalue(obj), mt);
    863         luaC_checkfinalizer(L, gcvalue(obj), mt);
    864       }
    865       break;
    866     }
    867     case LUA_TUSERDATA: {
    868       uvalue(obj)->metatable = mt;
    869       if (mt) {
    870         luaC_objbarrier(L, uvalue(obj), mt);
    871         luaC_checkfinalizer(L, gcvalue(obj), mt);
    872       }
    873       break;
    874     }
    875     default: {
    876       G(L)->mt[ttnov(obj)] = mt;
    877       break;
    878     }
    879   }
    880   L->top--;
    881   lua_unlock(L);
    882   return 1;
    883 }
    884 
    885 
    886 LUA_API void lua_setuservalue (lua_State *L, int idx) {
    887   StkId o;
    888   lua_lock(L);
    889   api_checknelems(L, 1);
    890   o = index2addr(L, idx);
    891   api_check(L, ttisfulluserdata(o), "full userdata expected");
    892   setuservalue(L, uvalue(o), L->top - 1);
    893   luaC_barrier(L, gcvalue(o), L->top - 1);
    894   L->top--;
    895   lua_unlock(L);
    896 }
    897 
    898 
    899 /*
    900 ** 'load' and 'call' functions (run Lua code)
    901 */
    902 
    903 
    904 #define checkresults(L,na,nr) \
    905      api_check(L, (nr) == LUA_MULTRET || (L->ci->top - L->top >= (nr) - (na)), \
    906 	"results from function overflow current stack size")
    907 
    908 
    909 LUA_API void lua_callk (lua_State *L, int nargs, int nresults,
    910                         lua_KContext ctx, lua_KFunction k) {
    911   StkId func;
    912   lua_lock(L);
    913   api_check(L, k == NULL || !isLua(L->ci),
    914     "cannot use continuations inside hooks");
    915   api_checknelems(L, nargs+1);
    916   api_check(L, L->status == LUA_OK, "cannot do calls on non-normal thread");
    917   checkresults(L, nargs, nresults);
    918   func = L->top - (nargs+1);
    919   if (k != NULL && L->nny == 0) {  /* need to prepare continuation? */
    920     L->ci->u.c.k = k;  /* save continuation */
    921     L->ci->u.c.ctx = ctx;  /* save context */
    922     luaD_call(L, func, nresults);  /* do the call */
    923   }
    924   else  /* no continuation or no yieldable */
    925     luaD_callnoyield(L, func, nresults);  /* just do the call */
    926   adjustresults(L, nresults);
    927   lua_unlock(L);
    928 }
    929 
    930 
    931 
    932 /*
    933 ** Execute a protected call.
    934 */
    935 struct CallS {  /* data to 'f_call' */
    936   StkId func;
    937   int nresults;
    938 };
    939 
    940 
    941 static void f_call (lua_State *L, void *ud) {
    942   struct CallS *c = cast(struct CallS *, ud);
    943   luaD_callnoyield(L, c->func, c->nresults);
    944 }
    945 
    946 
    947 
    948 LUA_API int lua_pcallk (lua_State *L, int nargs, int nresults, int errfunc,
    949                         lua_KContext ctx, lua_KFunction k) {
    950   struct CallS c;
    951   int status;
    952   ptrdiff_t func;
    953   lua_lock(L);
    954   api_check(L, k == NULL || !isLua(L->ci),
    955     "cannot use continuations inside hooks");
    956   api_checknelems(L, nargs+1);
    957   api_check(L, L->status == LUA_OK, "cannot do calls on non-normal thread");
    958   checkresults(L, nargs, nresults);
    959   if (errfunc == 0)
    960     func = 0;
    961   else {
    962     StkId o = index2addr(L, errfunc);
    963     api_checkstackindex(L, errfunc, o);
    964     func = savestack(L, o);
    965   }
    966   c.func = L->top - (nargs+1);  /* function to be called */
    967   if (k == NULL || L->nny > 0) {  /* no continuation or no yieldable? */
    968     c.nresults = nresults;  /* do a 'conventional' protected call */
    969     status = luaD_pcall(L, f_call, &c, savestack(L, c.func), func);
    970   }
    971   else {  /* prepare continuation (call is already protected by 'resume') */
    972     CallInfo *ci = L->ci;
    973     ci->u.c.k = k;  /* save continuation */
    974     ci->u.c.ctx = ctx;  /* save context */
    975     /* save information for error recovery */
    976     ci->extra = savestack(L, c.func);
    977     ci->u.c.old_errfunc = L->errfunc;
    978     L->errfunc = func;
    979     setoah(ci->callstatus, L->allowhook);  /* save value of 'allowhook' */
    980     ci->callstatus |= CIST_YPCALL;  /* function can do error recovery */
    981     luaD_call(L, c.func, nresults);  /* do the call */
    982     ci->callstatus &= ~CIST_YPCALL;
    983     L->errfunc = ci->u.c.old_errfunc;
    984     status = LUA_OK;  /* if it is here, there were no errors */
    985   }
    986   adjustresults(L, nresults);
    987   lua_unlock(L);
    988   return status;
    989 }
    990 
    991 
    992 LUA_API int lua_load (lua_State *L, lua_Reader reader, void *data,
    993                       const char *chunkname, const char *mode) {
    994   ZIO z;
    995   int status;
    996   lua_lock(L);
    997   if (!chunkname) chunkname = "?";
    998   luaZ_init(L, &z, reader, data);
    999   status = luaD_protectedparser(L, &z, chunkname, mode);
   1000   if (status == LUA_OK) {  /* no errors? */
   1001     LClosure *f = clLvalue(L->top - 1);  /* get newly created function */
   1002     if (f->nupvalues >= 1) {  /* does it have an upvalue? */
   1003       /* get global table from registry */
   1004       Table *reg = hvalue(&G(L)->l_registry);
   1005       const TValue *gt = luaH_getint(reg, LUA_RIDX_GLOBALS);
   1006       /* set global table as 1st upvalue of 'f' (may be LUA_ENV) */
   1007       setobj(L, f->upvals[0]->v, gt);
   1008       luaC_upvalbarrier(L, f->upvals[0]);
   1009     }
   1010   }
   1011   lua_unlock(L);
   1012   return status;
   1013 }
   1014 
   1015 
   1016 LUA_API int lua_dump (lua_State *L, lua_Writer writer, void *data, int strip) {
   1017   int status;
   1018   TValue *o;
   1019   lua_lock(L);
   1020   api_checknelems(L, 1);
   1021   o = L->top - 1;
   1022   if (isLfunction(o))
   1023     status = luaU_dump(L, getproto(o), writer, data, strip);
   1024   else
   1025     status = 1;
   1026   lua_unlock(L);
   1027   return status;
   1028 }
   1029 
   1030 
   1031 LUA_API int lua_status (lua_State *L) {
   1032   return L->status;
   1033 }
   1034 
   1035 
   1036 /*
   1037 ** Garbage-collection function
   1038 */
   1039 
   1040 LUA_API int lua_gc (lua_State *L, int what, int data) {
   1041   int res = 0;
   1042   global_State *g;
   1043   lua_lock(L);
   1044   g = G(L);
   1045   switch (what) {
   1046     case LUA_GCSTOP: {
   1047       g->gcrunning = 0;
   1048       break;
   1049     }
   1050     case LUA_GCRESTART: {
   1051       luaE_setdebt(g, 0);
   1052       g->gcrunning = 1;
   1053       break;
   1054     }
   1055     case LUA_GCCOLLECT: {
   1056       luaC_fullgc(L, 0);
   1057       break;
   1058     }
   1059     case LUA_GCCOUNT: {
   1060       /* GC values are expressed in Kbytes: #bytes/2^10 */
   1061       res = cast_int(gettotalbytes(g) >> 10);
   1062       break;
   1063     }
   1064     case LUA_GCCOUNTB: {
   1065       res = cast_int(gettotalbytes(g) & 0x3ff);
   1066       break;
   1067     }
   1068     case LUA_GCSTEP: {
   1069       l_mem debt = 1;  /* =1 to signal that it did an actual step */
   1070       lu_byte oldrunning = g->gcrunning;
   1071       g->gcrunning = 1;  /* allow GC to run */
   1072       if (data == 0) {
   1073         luaE_setdebt(g, -GCSTEPSIZE);  /* to do a "small" step */
   1074         luaC_step(L);
   1075       }
   1076       else {  /* add 'data' to total debt */
   1077         debt = cast(l_mem, data) * 1024 + g->GCdebt;
   1078         luaE_setdebt(g, debt);
   1079         luaC_checkGC(L);
   1080       }
   1081       g->gcrunning = oldrunning;  /* restore previous state */
   1082       if (debt > 0 && g->gcstate == GCSpause)  /* end of cycle? */
   1083         res = 1;  /* signal it */
   1084       break;
   1085     }
   1086     case LUA_GCSETPAUSE: {
   1087       res = g->gcpause;
   1088       g->gcpause = data;
   1089       break;
   1090     }
   1091     case LUA_GCSETSTEPMUL: {
   1092       res = g->gcstepmul;
   1093       if (data < 40) data = 40;  /* avoid ridiculous low values (and 0) */
   1094       g->gcstepmul = data;
   1095       break;
   1096     }
   1097     case LUA_GCISRUNNING: {
   1098       res = g->gcrunning;
   1099       break;
   1100     }
   1101     default: res = -1;  /* invalid option */
   1102   }
   1103   lua_unlock(L);
   1104   return res;
   1105 }
   1106 
   1107 
   1108 
   1109 /*
   1110 ** miscellaneous functions
   1111 */
   1112 
   1113 
   1114 LUA_API int lua_error (lua_State *L) {
   1115   lua_lock(L);
   1116   api_checknelems(L, 1);
   1117   luaG_errormsg(L);
   1118   /* code unreachable; will unlock when control actually leaves the kernel */
   1119   return 0;  /* to avoid warnings */
   1120 }
   1121 
   1122 
   1123 LUA_API int lua_next (lua_State *L, int idx) {
   1124   StkId t;
   1125   int more;
   1126   lua_lock(L);
   1127   t = index2addr(L, idx);
   1128   api_check(L, ttistable(t), "table expected");
   1129   more = luaH_next(L, hvalue(t), L->top - 1);
   1130   if (more) {
   1131     api_incr_top(L);
   1132   }
   1133   else  /* no more elements */
   1134     L->top -= 1;  /* remove key */
   1135   lua_unlock(L);
   1136   return more;
   1137 }
   1138 
   1139 
   1140 LUA_API void lua_concat (lua_State *L, int n) {
   1141   lua_lock(L);
   1142   api_checknelems(L, n);
   1143   if (n >= 2) {
   1144     luaV_concat(L, n);
   1145   }
   1146   else if (n == 0) {  /* push empty string */
   1147     setsvalue2s(L, L->top, luaS_newlstr(L, "", 0));
   1148     api_incr_top(L);
   1149   }
   1150   /* else n == 1; nothing to do */
   1151   luaC_checkGC(L);
   1152   lua_unlock(L);
   1153 }
   1154 
   1155 
   1156 LUA_API void lua_len (lua_State *L, int idx) {
   1157   StkId t;
   1158   lua_lock(L);
   1159   t = index2addr(L, idx);
   1160   luaV_objlen(L, L->top, t);
   1161   api_incr_top(L);
   1162   lua_unlock(L);
   1163 }
   1164 
   1165 
   1166 LUA_API lua_Alloc lua_getallocf (lua_State *L, void **ud) {
   1167   lua_Alloc f;
   1168   lua_lock(L);
   1169   if (ud) *ud = G(L)->ud;
   1170   f = G(L)->frealloc;
   1171   lua_unlock(L);
   1172   return f;
   1173 }
   1174 
   1175 
   1176 LUA_API void lua_setallocf (lua_State *L, lua_Alloc f, void *ud) {
   1177   lua_lock(L);
   1178   G(L)->ud = ud;
   1179   G(L)->frealloc = f;
   1180   lua_unlock(L);
   1181 }
   1182 
   1183 
   1184 LUA_API void *lua_newuserdata (lua_State *L, size_t size) {
   1185   Udata *u;
   1186   lua_lock(L);
   1187   u = luaS_newudata(L, size);
   1188   setuvalue(L, L->top, u);
   1189   api_incr_top(L);
   1190   luaC_checkGC(L);
   1191   lua_unlock(L);
   1192   return getudatamem(u);
   1193 }
   1194 
   1195 
   1196 
   1197 static const char *aux_upvalue (StkId fi, int n, TValue **val,
   1198                                 CClosure **owner, UpVal **uv) {
   1199   switch (ttype(fi)) {
   1200     case LUA_TCCL: {  /* C closure */
   1201       CClosure *f = clCvalue(fi);
   1202       if (!(1 <= n && n <= f->nupvalues)) return NULL;
   1203       *val = &f->upvalue[n-1];
   1204       if (owner) *owner = f;
   1205       return "";
   1206     }
   1207     case LUA_TLCL: {  /* Lua closure */
   1208       LClosure *f = clLvalue(fi);
   1209       TString *name;
   1210       Proto *p = f->p;
   1211       if (!(1 <= n && n <= p->sizeupvalues)) return NULL;
   1212       *val = f->upvals[n-1]->v;
   1213       if (uv) *uv = f->upvals[n - 1];
   1214       name = p->upvalues[n-1].name;
   1215       return (name == NULL) ? "(*no name)" : getstr(name);
   1216     }
   1217     default: return NULL;  /* not a closure */
   1218   }
   1219 }
   1220 
   1221 
   1222 LUA_API const char *lua_getupvalue (lua_State *L, int funcindex, int n) {
   1223   const char *name;
   1224   TValue *val = NULL;  /* to avoid warnings */
   1225   lua_lock(L);
   1226   name = aux_upvalue(index2addr(L, funcindex), n, &val, NULL, NULL);
   1227   if (name) {
   1228     setobj2s(L, L->top, val);
   1229     api_incr_top(L);
   1230   }
   1231   lua_unlock(L);
   1232   return name;
   1233 }
   1234 
   1235 
   1236 LUA_API const char *lua_setupvalue (lua_State *L, int funcindex, int n) {
   1237   const char *name;
   1238   TValue *val = NULL;  /* to avoid warnings */
   1239   CClosure *owner = NULL;
   1240   UpVal *uv = NULL;
   1241   StkId fi;
   1242   lua_lock(L);
   1243   fi = index2addr(L, funcindex);
   1244   api_checknelems(L, 1);
   1245   name = aux_upvalue(fi, n, &val, &owner, &uv);
   1246   if (name) {
   1247     L->top--;
   1248     setobj(L, val, L->top);
   1249     if (owner) { luaC_barrier(L, owner, L->top); }
   1250     else if (uv) { luaC_upvalbarrier(L, uv); }
   1251   }
   1252   lua_unlock(L);
   1253   return name;
   1254 }
   1255 
   1256 
   1257 static UpVal **getupvalref (lua_State *L, int fidx, int n, LClosure **pf) {
   1258   LClosure *f;
   1259   StkId fi = index2addr(L, fidx);
   1260   api_check(L, ttisLclosure(fi), "Lua function expected");
   1261   f = clLvalue(fi);
   1262   api_check(L, (1 <= n && n <= f->p->sizeupvalues), "invalid upvalue index");
   1263   if (pf) *pf = f;
   1264   return &f->upvals[n - 1];  /* get its upvalue pointer */
   1265 }
   1266 
   1267 
   1268 LUA_API void *lua_upvalueid (lua_State *L, int fidx, int n) {
   1269   StkId fi = index2addr(L, fidx);
   1270   switch (ttype(fi)) {
   1271     case LUA_TLCL: {  /* lua closure */
   1272       return *getupvalref(L, fidx, n, NULL);
   1273     }
   1274     case LUA_TCCL: {  /* C closure */
   1275       CClosure *f = clCvalue(fi);
   1276       api_check(L, 1 <= n && n <= f->nupvalues, "invalid upvalue index");
   1277       return &f->upvalue[n - 1];
   1278     }
   1279     default: {
   1280       api_check(L, 0, "closure expected");
   1281       return NULL;
   1282     }
   1283   }
   1284 }
   1285 
   1286 
   1287 LUA_API void lua_upvaluejoin (lua_State *L, int fidx1, int n1,
   1288                                             int fidx2, int n2) {
   1289   LClosure *f1;
   1290   UpVal **up1 = getupvalref(L, fidx1, n1, &f1);
   1291   UpVal **up2 = getupvalref(L, fidx2, n2, NULL);
   1292   luaC_upvdeccount(L, *up1);
   1293   *up1 = *up2;
   1294   (*up1)->refcount++;
   1295   if (upisopen(*up1)) (*up1)->u.open.touched = 1;
   1296   luaC_upvalbarrier(L, *up1);
   1297 }
   1298 
   1299
	mudgangster Tiny, scriptable MUD client
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