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/*** $Id: lvm.c,v 2.152 2012/06/08 15:14:04 roberto Exp $** Lua virtual machine** See Copyright Notice in lua.h*/  #include <stdio.h>#include <stdlib.h>#include <string.h> #define lvm_c#define LUA_CORE #include "lua.h" #include "ldebug.h"#include "ldo.h"#include "lfunc.h"#include "lgc.h"#include "lobject.h"#include "lopcodes.h"#include "lstate.h"#include "lstring.h"#include "ltable.h"#include "ltm.h"#include "lvm.h"   /* limit for table tag-method chains (to avoid loops) */#define MAXTAGLOOP	100  const TValue *luaV_tonumber (const TValue *obj, TValue *n) {  lua_Number num;  if (ttisnumber(obj)) return obj;  if (ttisstring(obj) && luaO_str2d(svalue(obj), tsvalue(obj)->len, &num)) {    setnvalue(n, num);    return n;  }  else    return NULL;}  int luaV_tostring (lua_State *L, StkId obj) {  if (!ttisnumber(obj))    return 0;  else {    char s[LUAI_MAXNUMBER2STR];    lua_Number n = nvalue(obj);    int l = lua_number2str(s, n);    setsvalue2s(L, obj, luaS_newlstr(L, s, l));    return 1;  }}  static void traceexec (lua_State *L) {  CallInfo *ci = L->ci;  lu_byte mask = L->hookmask;  int counthook = ((mask & LUA_MASKCOUNT) && L->hookcount == 0);  if (counthook)    resethookcount(L);  /* reset count */  if (ci->callstatus & CIST_HOOKYIELD) {  /* called hook last time? */    ci->callstatus &= ~CIST_HOOKYIELD;  /* erase mark */    return;  /* do not call hook again (VM yielded, so it did not move) */  }  if (counthook)    luaD_hook(L, LUA_HOOKCOUNT, -1);  /* call count hook */  if (mask & LUA_MASKLINE) {    Proto *p = ci_func(ci)->p;    int npc = pcRel(ci->u.l.savedpc, p);    int newline = getfuncline(p, npc);    if (npc == 0 ||  /* call linehook when enter a new function, */        ci->u.l.savedpc <= L->oldpc ||  /* when jump back (loop), or when */        newline != getfuncline(p, pcRel(L->oldpc, p)))  /* enter a new line */      luaD_hook(L, LUA_HOOKLINE, newline);  /* call line hook */  }  L->oldpc = ci->u.l.savedpc;  if (L->status == LUA_YIELD) {  /* did hook yield? */    if (counthook)      L->hookcount = 1;  /* undo decrement to zero */    ci->u.l.savedpc--;  /* undo increment (resume will increment it again) */    ci->callstatus |= CIST_HOOKYIELD;  /* mark that it yieled */    ci->func = L->top - 1;  /* protect stack below results */    luaD_throw(L, LUA_YIELD);  }}  static void callTM (lua_State *L, const TValue *f, const TValue *p1,                    const TValue *p2, TValue *p3, int hasres) {  ptrdiff_t result = savestack(L, p3);  setobj2s(L, L->top++, f);  /* push function */  setobj2s(L, L->top++, p1);  /* 1st argument */  setobj2s(L, L->top++, p2);  /* 2nd argument */  if (!hasres)  /* no result? 'p3' is third argument */    setobj2s(L, L->top++, p3);  /* 3rd argument */  luaD_checkstack(L, 0);  /* metamethod may yield only when called from Lua code */  luaD_call(L, L->top - (4 - hasres), hasres, isLua(L->ci));  if (hasres) {  /* if has result, move it to its place */    p3 = restorestack(L, result);    setobjs2s(L, p3, --L->top);  }}  void luaV_gettable (lua_State *L, const TValue *t, TValue *key, StkId val) {  int loop;  for (loop = 0; loop < MAXTAGLOOP; loop++) {    const TValue *tm;    if (ttistable(t)) {  /* `t' is a table? */      Table *h = hvalue(t);      const TValue *res = luaH_get(h, key); /* do a primitive get */      if (!ttisnil(res) ||  /* result is not nil? */          (tm = fasttm(L, h->metatable, TM_INDEX)) == NULL) { /* or no TM? */        setobj2s(L, val, res);        return;      }      /* else will try the tag method */    }    else if (ttisnil(tm = luaT_gettmbyobj(L, t, TM_INDEX)))      luaG_typeerror(L, t, "index");    if (ttisfunction(tm)) {      callTM(L, tm, t, key, val, 1);      return;    }    t = tm;  /* else repeat with 'tm' */  }  luaG_runerror(L, "loop in gettable");}  void luaV_settable (lua_State *L, const TValue *t, TValue *key, StkId val) {  int loop;  for (loop = 0; loop < MAXTAGLOOP; loop++) {    const TValue *tm;    if (ttistable(t)) {  /* `t' is a table? */      Table *h = hvalue(t);      TValue *oldval = cast(TValue *, luaH_get(h, key));      /* if previous value is not nil, there must be a previous entry         in the table; moreover, a metamethod has no relevance */      if (!ttisnil(oldval) ||         /* previous value is nil; must check the metamethod */         ((tm = fasttm(L, h->metatable, TM_NEWINDEX)) == NULL &&         /* no metamethod; is there a previous entry in the table? */         (oldval != luaO_nilobject ||         /* no previous entry; must create one. (The next test is            always true; we only need the assignment.) */         (oldval = luaH_newkey(L, h, key), 1)))) {        /* no metamethod and (now) there is an entry with given key */        setobj2t(L, oldval, val);  /* assign new value to that entry */        invalidateTMcache(h);        luaC_barrierback(L, obj2gco(h), val);        return;      }      /* else will try the metamethod */    }    else  /* not a table; check metamethod */      if (ttisnil(tm = luaT_gettmbyobj(L, t, TM_NEWINDEX)))        luaG_typeerror(L, t, "index");    /* there is a metamethod */    if (ttisfunction(tm)) {      callTM(L, tm, t, key, val, 0);      return;    }    t = tm;  /* else repeat with 'tm' */  }  luaG_runerror(L, "loop in settable");}  static int call_binTM (lua_State *L, const TValue *p1, const TValue *p2,                       StkId res, TMS event) {  const TValue *tm = luaT_gettmbyobj(L, p1, event);  /* try first operand */  if (ttisnil(tm))    tm = luaT_gettmbyobj(L, p2, event);  /* try second operand */  if (ttisnil(tm)) return 0;  callTM(L, tm, p1, p2, res, 1);  return 1;}  static const TValue *get_equalTM (lua_State *L, Table *mt1, Table *mt2,                                  TMS event) {  const TValue *tm1 = fasttm(L, mt1, event);  const TValue *tm2;  if (tm1 == NULL) return NULL;  /* no metamethod */  if (mt1 == mt2) return tm1;  /* same metatables => same metamethods */  tm2 = fasttm(L, mt2, event);  if (tm2 == NULL) return NULL;  /* no metamethod */  if (luaV_rawequalobj(tm1, tm2))  /* same metamethods? */    return tm1;  return NULL;}  static int call_orderTM (lua_State *L, const TValue *p1, const TValue *p2,                         TMS event) {  if (!call_binTM(L, p1, p2, L->top, event))    return -1;  /* no metamethod */  else    return !l_isfalse(L->top);}  static int l_strcmp (const TString *ls, const TString *rs) {  const char *l = getstr(ls);  size_t ll = ls->tsv.len;  const char *r = getstr(rs);  size_t lr = rs->tsv.len;  for (;;) {    int temp = strcoll(l, r);    if (temp != 0) return temp;    else {  /* strings are equal up to a `\0' */      size_t len = strlen(l);  /* index of first `\0' in both strings */      if (len == lr)  /* r is finished? */        return (len == ll) ? 0 : 1;      else if (len == ll)  /* l is finished? */        return -1;  /* l is smaller than r (because r is not finished) */      /* both strings longer than `len'; go on comparing (after the `\0') */      len++;      l += len; ll -= len; r += len; lr -= len;    }  }}  int luaV_lessthan (lua_State *L, const TValue *l, const TValue *r) {  int res;  if (ttisnumber(l) && ttisnumber(r))    return luai_numlt(L, nvalue(l), nvalue(r));  else if (ttisstring(l) && ttisstring(r))    return l_strcmp(rawtsvalue(l), rawtsvalue(r)) < 0;  else if ((res = call_orderTM(L, l, r, TM_LT)) < 0)    luaG_ordererror(L, l, r);  return res;}  int luaV_lessequal (lua_State *L, const TValue *l, const TValue *r) {  int res;  if (ttisnumber(l) && ttisnumber(r))    return luai_numle(L, nvalue(l), nvalue(r));  else if (ttisstring(l) && ttisstring(r))    return l_strcmp(rawtsvalue(l), rawtsvalue(r)) <= 0;  else if ((res = call_orderTM(L, l, r, TM_LE)) >= 0)  /* first try `le' */    return res;  else if ((res = call_orderTM(L, r, l, TM_LT)) < 0)  /* else try `lt' */    luaG_ordererror(L, l, r);  return !res;}  /*** equality of Lua values. L == NULL means raw equality (no metamethods)*/int luaV_equalobj_ (lua_State *L, const TValue *t1, const TValue *t2) {  const TValue *tm;  lua_assert(ttisequal(t1, t2));  switch (ttype(t1)) {    case LUA_TNIL: return 1;    case LUA_TNUMBER: return luai_numeq(nvalue(t1), nvalue(t2));    case LUA_TBOOLEAN: return bvalue(t1) == bvalue(t2);  /* true must be 1 !! */    case LUA_TLIGHTUSERDATA: return pvalue(t1) == pvalue(t2);    case LUA_TLCF: return fvalue(t1) == fvalue(t2);    case LUA_TSHRSTR: return eqshrstr(rawtsvalue(t1), rawtsvalue(t2));    case LUA_TLNGSTR: return luaS_eqlngstr(rawtsvalue(t1), rawtsvalue(t2));    case LUA_TUSERDATA: {      if (uvalue(t1) == uvalue(t2)) return 1;      else if (L == NULL) return 0;      tm = get_equalTM(L, uvalue(t1)->metatable, uvalue(t2)->metatable, TM_EQ);      break;  /* will try TM */    }    case LUA_TTABLE: {      if (hvalue(t1) == hvalue(t2)) return 1;      else if (L == NULL) return 0;      tm = get_equalTM(L, hvalue(t1)->metatable, hvalue(t2)->metatable, TM_EQ);      break;  /* will try TM */    }    default:      lua_assert(iscollectable(t1));      return gcvalue(t1) == gcvalue(t2);  }  if (tm == NULL) return 0;  /* no TM? */  callTM(L, tm, t1, t2, L->top, 1);  /* call TM */  return !l_isfalse(L->top);}  void luaV_concat (lua_State *L, int total) {  lua_assert(total >= 2);  do {    StkId top = L->top;    int n = 2;  /* number of elements handled in this pass (at least 2) */    if (!(ttisstring(top-2) || ttisnumber(top-2)) || !tostring(L, top-1)) {      if (!call_binTM(L, top-2, top-1, top-2, TM_CONCAT))        luaG_concaterror(L, top-2, top-1);    }    else if (tsvalue(top-1)->len == 0)  /* second operand is empty? */      (void)tostring(L, top - 2);  /* result is first operand */    else if (ttisstring(top-2) && tsvalue(top-2)->len == 0) {      setobjs2s(L, top - 2, top - 1);  /* result is second op. */    }    else {      /* at least two non-empty string values; get as many as possible */      size_t tl = tsvalue(top-1)->len;      char *buffer;      int i;      /* collect total length */      for (i = 1; i < total && tostring(L, top-i-1); i++) {        size_t l = tsvalue(top-i-1)->len;        if (l >= (MAX_SIZET/sizeof(char)) - tl)          luaG_runerror(L, "string length overflow");        tl += l;      }      buffer = luaZ_openspace(L, &G(L)->buff, tl);      tl = 0;      n = i;      do {  /* concat all strings */        size_t l = tsvalue(top-i)->len;        memcpy(buffer+tl, svalue(top-i), l * sizeof(char));        tl += l;      } while (--i > 0);      setsvalue2s(L, top-n, luaS_newlstr(L, buffer, tl));    }    total -= n-1;  /* got 'n' strings to create 1 new */    L->top -= n-1;  /* popped 'n' strings and pushed one */  } while (total > 1);  /* repeat until only 1 result left */}  void luaV_objlen (lua_State *L, StkId ra, const TValue *rb) {  const TValue *tm;  switch (ttypenv(rb)) {    case LUA_TTABLE: {      Table *h = hvalue(rb);      tm = fasttm(L, h->metatable, TM_LEN);      if (tm) break;  /* metamethod? break switch to call it */      setnvalue(ra, cast_num(luaH_getn(h)));  /* else primitive len */      return;    }    case LUA_TSTRING: {      setnvalue(ra, cast_num(tsvalue(rb)->len));      return;    }    default: {  /* try metamethod */      tm = luaT_gettmbyobj(L, rb, TM_LEN);      if (ttisnil(tm))  /* no metamethod? */        luaG_typeerror(L, rb, "get length of");      break;    }  }  callTM(L, tm, rb, rb, ra, 1);}  void luaV_arith (lua_State *L, StkId ra, const TValue *rb,                 const TValue *rc, TMS op) {  TValue tempb, tempc;  const TValue *b, *c;  if ((b = luaV_tonumber(rb, &tempb)) != NULL &&      (c = luaV_tonumber(rc, &tempc)) != NULL) {    lua_Number res = luaO_arith(op - TM_ADD + LUA_OPADD, nvalue(b), nvalue(c));    setnvalue(ra, res);  }  else if (!call_binTM(L, rb, rc, ra, op))    luaG_aritherror(L, rb, rc);}  /*** check whether cached closure in prototype 'p' may be reused, that is,** whether there is a cached closure with the same upvalues needed by** new closure to be created.*/static Closure *getcached (Proto *p, UpVal **encup, StkId base) {  Closure *c = p->cache;  if (c != NULL) {  /* is there a cached closure? */    int nup = p->sizeupvalues;    Upvaldesc *uv = p->upvalues;    int i;    for (i = 0; i < nup; i++) {  /* check whether it has right upvalues */      TValue *v = uv[i].instack ? base + uv[i].idx : encup[uv[i].idx]->v;      if (c->l.upvals[i]->v != v)        return NULL;  /* wrong upvalue; cannot reuse closure */    }  }  return c;  /* return cached closure (or NULL if no cached closure) */}  /*** create a new Lua closure, push it in the stack, and initialize** its upvalues. Note that the call to 'luaC_barrierproto' must come** before the assignment to 'p->cache', as the function needs the** original value of that field.*/static void pushclosure (lua_State *L, Proto *p, UpVal **encup, StkId base,                         StkId ra) {  int nup = p->sizeupvalues;  Upvaldesc *uv = p->upvalues;  int i;  Closure *ncl = luaF_newLclosure(L, nup);  ncl->l.p = p;  setclLvalue(L, ra, ncl);  /* anchor new closure in stack */  for (i = 0; i < nup; i++) {  /* fill in its upvalues */    if (uv[i].instack)  /* upvalue refers to local variable? */      ncl->l.upvals[i] = luaF_findupval(L, base + uv[i].idx);    else  /* get upvalue from enclosing function */      ncl->l.upvals[i] = encup[uv[i].idx];  }  luaC_barrierproto(L, p, ncl);  p->cache = ncl;  /* save it on cache for reuse */}  /*** finish execution of an opcode interrupted by an yield*/void luaV_finishOp (lua_State *L) {  CallInfo *ci = L->ci;  StkId base = ci->u.l.base;  Instruction inst = *(ci->u.l.savedpc - 1);  /* interrupted instruction */  OpCode op = GET_OPCODE(inst);  switch (op) {  /* finish its execution */    case OP_ADD: case OP_SUB: case OP_MUL: case OP_DIV:    case OP_MOD: case OP_POW: case OP_UNM: case OP_LEN:    case OP_GETTABUP: case OP_GETTABLE: case OP_SELF: {      setobjs2s(L, base + GETARG_A(inst), --L->top);      break;    }    case OP_LE: case OP_LT: case OP_EQ: {      int res = !l_isfalse(L->top - 1);      L->top--;      /* metamethod should not be called when operand is K */      lua_assert(!ISK(GETARG_B(inst)));      if (op == OP_LE &&  /* "<=" using "<" instead? */          ttisnil(luaT_gettmbyobj(L, base + GETARG_B(inst), TM_LE)))        res = !res;  /* invert result */      lua_assert(GET_OPCODE(*ci->u.l.savedpc) == OP_JMP);      if (res != GETARG_A(inst))  /* condition failed? */        ci->u.l.savedpc++;  /* skip jump instruction */      break;    }    case OP_CONCAT: {      StkId top = L->top - 1;  /* top when 'call_binTM' was called */      int b = GETARG_B(inst);      /* first element to concatenate */      int total = cast_int(top - 1 - (base + b));  /* yet to concatenate */      setobj2s(L, top - 2, top);  /* put TM result in proper position */      if (total > 1) {  /* are there elements to concat? */        L->top = top - 1;  /* top is one after last element (at top-2) */        luaV_concat(L, total);  /* concat them (may yield again) */      }      /* move final result to final position */      setobj2s(L, ci->u.l.base + GETARG_A(inst), L->top - 1);      L->top = ci->top;  /* restore top */      break;    }    case OP_TFORCALL: {      lua_assert(GET_OPCODE(*ci->u.l.savedpc) == OP_TFORLOOP);      L->top = ci->top;  /* correct top */      break;    }    case OP_CALL: {      if (GETARG_C(inst) - 1 >= 0)  /* nresults >= 0? */        L->top = ci->top;  /* adjust results */      break;    }    case OP_TAILCALL: case OP_SETTABUP:  case OP_SETTABLE:      break;    default: lua_assert(0);  }}   /*** some macros for common tasks in `luaV_execute'*/ #if !defined luai_runtimecheck#define luai_runtimecheck(L, c)		/* void */#endif  #define RA(i)	(base+GETARG_A(i))/* to be used after possible stack reallocation */#define RB(i)	check_exp(getBMode(GET_OPCODE(i)) == OpArgR, base+GETARG_B(i))#define RC(i)	check_exp(getCMode(GET_OPCODE(i)) == OpArgR, base+GETARG_C(i))#define RKB(i)	check_exp(getBMode(GET_OPCODE(i)) == OpArgK, \	ISK(GETARG_B(i)) ? k+INDEXK(GETARG_B(i)) : base+GETARG_B(i))#define RKC(i)	check_exp(getCMode(GET_OPCODE(i)) == OpArgK, \	ISK(GETARG_C(i)) ? k+INDEXK(GETARG_C(i)) : base+GETARG_C(i))#define KBx(i)  \  (k + (GETARG_Bx(i) != 0 ? GETARG_Bx(i) - 1 : GETARG_Ax(*ci->u.l.savedpc++))) 

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