C++ cast_int函数代码示例

static const char *findvararg (CallInfo *ci, int n, StkId *pos) {
  int nparams = clLvalue(ci->func)->p->sp->numparams;
  if (n >= cast_int(ci->u.l.base - ci->func) - nparams)
    return NULL;  /* no such vararg */
  else {
    *pos = ci->func + nparams + n;
    return "(*vararg)";  /* generic name for any vararg */
  }
}

/*
** converts an integer to a "floating point byte", represented as
** (eeeeexxx), where the real value is (1xxx) * 2^(eeeee - 1) if
** eeeee != 0 and (xxx) otherwise.
*/
int luaO_int2fb (unsigned int x) {
  int e = 0;  /* exponent */
  if (x < 8) return x;
  while (x >= 0x10) {
    x = (x+1) >> 1;
    e++;
  }
  return ((e+1) << 3) | (cast_int(x) - 8);
}

static int addk (FuncState *fs, TValue *k, TValue *v) {
    lua_State *L = fs->L;
    TValue *idx = luaH_set(L, fs->h, k);
    Proto *f = fs->f;
    int oldsize = f->sizek;
    if (ttisnumber(idx)) {
        lua_assert(luaO_rawequalObj(&fs->f->k[cast_int(nvalue(idx))], v));
        return cast_int(nvalue(idx));
    } else { /* constant not found; create a new entry */
        setnvalue(idx, cast_num(fs->nk));
        luaM_growvector(L, f->k, fs->nk, f->sizek, TValue,
                        MAXARG_Bx, "constant table overflow");
        while (oldsize < f->sizek) setnilvalue(&f->k[oldsize++]);
        setobj(L, &f->k[fs->nk], v);
        luaC_barrier(L, f, v);
        return fs->nk++;
    }
}

/*
** converts an integer to a "floating point byte", represented as
** (eeeeexxx), where the real value is (1xxx) * 2^(eeeee - 1) if
** eeeee != 0 and (xxx) otherwise.
*/
int luaO_int2fb (unsigned int x) {
  int e = 0;  /* expoent */
  while (x >= 16) {
    x = (x+1) >> 1;
    e++;
  }
  if (x < 8) return x;
  else return ((e+1) << 3) | (cast_int(x) - 8);
}

int HiroHand::readAngle(int idx)
{
  int ang;

  ang = cast_int(this->modules[idx]->getAngle());
  if(ang == 0xF000)
    std::cerr << "Angle Read Error" << std::endl;

  return ang;
}

static const char *getfuncname (lua_State *L, CallInfo *ci, const char **name) {
  TMS tm = (TMS)0;  /* to avoid warnings */
  Proto *p = ci_func(ci)->p;  /* calling function */
  int pc = currentpc(ci);  /* calling instruction index */
  Instruction i = p->code[pc];  /* calling instruction */
  if (ci->callstatus & CIST_HOOKED) {  /* was it called inside a hook? */
    *name = "?";
    return "hook";
  }
  switch (GET_OPCODE(i)) {
    case OP_CALL:
    case OP_TAILCALL:  /* get function name */
      return getobjname(p, pc, GETARG_A(i), name);
    case OP_TFORCALL: {  /* for iterator */
      *name = "for iterator";
       return "for iterator";
    }
    /* all other instructions can call only through metamethods */
    case OP_SELF: case OP_GETTABUP: case OP_GETTABLE:
      tm = TM_INDEX;
      break;
    case OP_SETTABUP: case OP_SETTABLE:
      tm = TM_NEWINDEX;
      break;
    case OP_ADD: case OP_SUB: case OP_MUL: case OP_MOD:
    case OP_POW: case OP_DIV: case OP_IDIV: case OP_BAND:
    case OP_BOR: case OP_BXOR: case OP_SHL: case OP_SHR: {
      int offset = cast_int(GET_OPCODE(i)) - cast_int(OP_ADD);  /* ORDER OP */
      tm = cast(TMS, offset + cast_int(TM_ADD));  /* ORDER TM */
      break;
    }
    case OP_UNM: tm = TM_UNM; break;
    case OP_BNOT: tm = TM_BNOT; break;
    case OP_LEN: tm = TM_LEN; break;
    case OP_CONCAT: tm = TM_CONCAT; break;
    case OP_EQ: tm = TM_EQ; break;
    case OP_LT: tm = TM_LT; break;
    case OP_LE: tm = TM_LE; break;
    default: lua_assert(0);  /* other instructions cannot call a function */
  }
  *name = getstr(G(L)->tmname[tm]);
  return "metamethod";
}

static void restore_stack_limit(lua_State *L)
{
	lua_assert(L->stack_last - L->stack == L->stacksize - EXTRA_STACK - 1);
	if (L->size_ci > LUAI_MAXCALLS)
	{ /* there was an overflow? */
		int inuse = cast_int(L->ci - L->base_ci);
		if (inuse + 1 < LUAI_MAXCALLS) /* can `undo' overflow? */
			luaD_reallocCI(L, LUAI_MAXCALLS);
	}
}

/*
** 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);
  }
}

/*
** returns the index for `key' if `key' is an appropriate key to live in
** the array part of the table, -1 otherwise.
**
** Anything <=0 is taken as not being in the array part.
*/
static int arrayindex (const TValue *key, int max) {
  lua_Integer i;
  switch( ttype(key) ) {
#ifdef LUA_TINT
    case LUA_TINT:      i= ivalue(key); break;
#endif
    case LUA_TNUMBER:   if (tt_integer_valued(key,&i)) break;
    default:            return -1;  /* not to be used as array index */
  }
  return (i <= max) ? cast_int(i) : -1;
}

void luaG_typeerror (lua_State *L, const TValue *o, const char *op) {
  const char *name = NULL;
  const char *t = luaT_typenames[ttype(o)];
  const char *kind = (isinstack(L->ci, o)) ?
                         getobjname(L, L->ci, cast_int(o - L->base), &name) :
                         NULL;
  if (kind)
    luaG_runerror(L, "attempt to %s %s " LUA_QS " (a %s value)",
                op, kind, name, t);
  else
    luaG_runerror(L, "attempt to %s a %s value", op, t);
}

static int searchvar(FuncState *fs, TString *n)
{
    int i;

    for (i = cast_int(fs->nactvar) - 1; i >= 0; i--)
    {
        if (luaS_eqstr(n, getlocvar(fs, i)->varname))
            return i;
    }

    return -1; /* not found */
}

static const char *varinfo (lua_State *L, const TValue *o) {
  const char *name = NULL;  /* to avoid warnings */
  CallInfo *ci = L->ci;
  const char *kind = NULL;
  if (isLua(ci)) {
    kind = getupvalname(ci, o, &name);  /* check whether 'o' is an upvalue */
    if (!kind && isinstack(ci, o))  /* no? try a register */
      kind = getobjname(ci_func(ci)->p, currentpc(ci),
                        cast_int(o - ci->u.l.base), &name);
  }
  return (kind) ? luaO_pushfstring(L, " (%s '%s')", kind, name) : "";
}

double approx(double a, int digits) {
	
	
	
	digits--;
	bool neg=false;
	if(a<0) {
	
		neg=true;
		a=-a;
		
	}
		
	//cout<<a<<endl;
	
	int tpow=0;
	while(a<pow(10, digits)) {
		
		tpow++;
		a*=10;
		
		
	}
	while(a>pow(10, digits+1)) {
		
		tpow--;
		a/=10;
		
		
	}

	
	if(neg==false)
		return cast_int(a)/pow(10, tpow);
	else
		return -cast_int(a)/pow(10, tpow);



}

static int traversestack (global_State *g, lua_State *L) {
  StkId o = L->stack;
  if (o == NULL)
    return 1;  /* stack not completely built yet */
  for (; o < L->top; o++)
    markvalue(g, o);
  if (g->gcstate == GCSatomic) {  /* final traversal? */
    StkId lim = L->stack + L->stacksize;  /* real end of stack */
    for (; o < lim; o++)  /* clear not-marked stack slice */
      setnilvalue(o);
  }
  return TRAVCOST + cast_int(o - L->stack);
}

/*
** converts an integer to a "floating point byte", represented as
** (eeeeexxx), where the real value is (1xxx) * 2^(eeeee - 1) if
** eeeee != 0 and (xxx) otherwise.
*/
int luaO_int2fb (unsigned int x) {
	int e = 0;  /* exponent */
	if (x < 8) return x;
	while (x >= (8 << 4)) {  /* coarse steps */
		x = (x + 0xf) >> 4;  /* x = ceil(x / 16) */
		e += 4;
	}
	while (x >= (8 << 1)) {  /* fine steps */
		x = (x + 1) >> 1;  /* x = ceil(x / 2) */
		e++;
	}
	return ((e+1) << 3) | (cast_int(x) - 8);
}