C++ decNumberIsZero函数代码示例

_RETURN_TYPE
INTERNAL_FUNCTION_NAME (DEC_TYPE x)
{
  DEC_TYPE result;
  decContext context;
  decNumber dn_result;
  decNumber dn_x;
  decNumber dn_absx;
  decNumber dn_logx;
  decNumber dn_one;
  decNumber dn_cmp;
  enum rounding round;

  FUNC_CONVERT_TO_DN (&x, &dn_x);
  if (decNumberIsZero (&dn_x))
    {
      DFP_EXCEPT (FE_INVALID);
      DFP_ERRNO (EDOM);
      return _FBLOG0;
    }
  if (decNumberIsInfinite (&dn_x))
    {
      DFP_EXCEPT (FE_INVALID);
      DFP_ERRNO (EDOM);
      return decNumberIsNegative (&dn_x) ? _MIN_VALUE : _MAX_VALUE;
    }
  if (decNumberIsNaN (&dn_x))
    {
      DFP_EXCEPT (FE_INVALID);
      DFP_ERRNO (EDOM);
      return _FBLOGNAN;
    }

  decContextDefault (&context, DEFAULT_CONTEXT);

  decNumberAbs (&dn_absx, &dn_x, &context);

  /* For DFP, we use radix 10 instead of whatever FLT_RADIX happens to be */
  decNumberLog10 (&dn_logx, &dn_absx, &context);

  /* Capture the case where truncation will return the wrong result,
     by rounding up if -1.0 < x < 1.0  */
  round = DEC_ROUND_DOWN;
  decNumberFromInt32 (&dn_one, 1);
  decNumberCompare (&dn_cmp, &dn_x, &dn_one, &context);
  if (-decNumberIsNegative(&dn_cmp))
    {
      decNumberFromInt32 (&dn_one, -1);
      decNumberCompare (&dn_cmp, &dn_x, &dn_one, &context);
      if (!decNumberIsNegative(&dn_cmp) && !decNumberIsZero(&dn_cmp))
	round = DEC_ROUND_UP;
    }
  context.round = round;

  decNumberToIntegralValue (&dn_result, &dn_logx, &context);

  FUNC_CONVERT_FROM_DN (&dn_result, &result, &context);
  /* Use _Decimal* to int casting.  */
  return (_RETURN_TYPE) result;
}

DEC_TYPE
INTERNAL_FUNCTION_NAME (DEC_TYPE x)
{
  decContext context;
  decNumber dn_result;
  DEC_TYPE result;
  decNumber dn_x;
  decNumber dn_tmp;
  decNumber dn_log10;
  decNumber dn_one;
  decNumber dn_cmp;
  enum rounding round;

  FUNC_CONVERT_TO_DN (&x, &dn_x);
  if (decNumberIsNaN (&dn_x))
    return x+x;
  if (decNumberIsInfinite (&dn_x))	/* +-Inf: Inf  */
    return DEC_INFINITY;
  if (decNumberIsZero (&dn_x))	/*  Pole Error if x==0 */
    {
      DFP_ERRNO (ERANGE);
      DFP_EXCEPT (FE_DIVBYZERO);
      return -DFP_HUGE_VAL;
    }
  if (decNumberIsInfinite (&dn_x) && decNumberIsNegative (&dn_x))
    return -x;

  decContextDefault (&context, DEFAULT_CONTEXT);
  decNumberAbs (&dn_tmp, &dn_x, &context);
  /*  For DFP, we use radix 10 instead of whatever FLT_RADIX
      happens to be */
  decNumberLog10 (&dn_log10, &dn_tmp, &context);

  /* Capture the case where truncation will return the wrong result,
     by rounding up if -1.0 < x < 1.0  */
  round = DEC_ROUND_DOWN;
  decNumberFromInt32 (&dn_one, 1);
  decNumberCompare (&dn_cmp, &dn_x, &dn_one, &context);
  if (-decNumberIsNegative(&dn_cmp))
    {
      decNumberFromInt32 (&dn_one, -1);
      decNumberCompare (&dn_cmp, &dn_x, &dn_one, &context);
      if (!decNumberIsNegative(&dn_cmp) && !decNumberIsZero(&dn_cmp))
	round = DEC_ROUND_UP;
    }
  context.round = round;

  decNumberToIntegralValue (&dn_result, &dn_log10, &context);

  FUNC_CONVERT_FROM_DN (&dn_result, &result, &context);

  return result;
}

int
__fpclassifyd64 (_Decimal64 x)
{
  decNumber dn_x;
  decContext context;

  FUNC_CONVERT_TO_DN (&x, &dn_x);

  if (decNumberIsNaN (&dn_x))
    return FP_NAN;
  else if (decNumberIsInfinite (&dn_x))
    return FP_INFINITE;
  else if (decNumberIsZero (&dn_x))
    return FP_ZERO;

  /* Since DFP value are not normalized, checking the exponent for
     normal/subnormal is not suffice.  For instance, the value 10e-96 will
     result in a expoenent below the minimum, however it is still a FP_NORMAL
     number due implicit normalization.  TO avoid such traps the check relies
     on runtime comparisons.  */
  decContextDefault (&context, DEC_INIT_DECIMAL64);
  if (decNumberIsSubnormal (&dn_x, &context))
    return FP_SUBNORMAL;

  return FP_NORMAL;
}

_Decimal128
__quantumd128 (_Decimal128 x)
{
  decNumber dn_x;
  decNumber dn_result;
  decContext context;
  _Decimal128 result;

  FUNC_CONVERT_TO_DN (&x, &dn_x);
  if (decNumberIsNaN (&dn_x) || decNumberIsZero (&dn_x))
    return x;
  if (decNumberIsInfinite (&dn_x))
    return DEC_INFINITY;

  /* The quantum of a finite number is defined as 1 x 10^exponent, so
     first get input absolute value and then sets its coefficient to 1.  */
  decContextDefault (&context, DEFAULT_CONTEXT);
  decNumberAbs (&dn_result, &dn_x, &context);
  dn_result.digits = 1;
  dn_result.lsu[0] = 1;

  FUNC_CONVERT_FROM_DN (&dn_result, &result, &context);

  return result;
}

DEC_TYPE
INTERNAL_FUNCTION_NAME (DEC_TYPE x)
{
  decContext context;
  decNumber dn_result;
  DEC_TYPE result, one;
  decNumber dn_x, dn_one;

  one = DFP_CONSTANT(1.0);
  FUNC_CONVERT_TO_DN (&one, &dn_one);
  FUNC_CONVERT_TO_DN (&x, &dn_x);

  if (decNumberIsNaN (&dn_x) || decNumberIsZero (&dn_x)
	|| decNumberIsInfinite (&dn_x))
    {
      return x + x;
    }
  decContextDefault (&context, DEFAULT_CONTEXT);

  /* using trig identity: acosh(x) = log(x+sqrt(x*x-1)) */
  decNumberMultiply (&dn_result, &dn_x, &dn_x, &context);
  decNumberAdd (&dn_result, &dn_result, &dn_one, &context);
  decNumberSquareRoot (&dn_result, &dn_result, &context);
  decNumberAdd (&dn_result, &dn_result, &dn_x, &context);
  decNumberLn (&dn_result, &dn_result, &context);

  FUNC_CONVERT_FROM_DN (&dn_result, &result, &context);

  return result;
}

// -------------------------------------
// Appends the digit to the digit list if it's not out of scope.
// Ignores the digit, otherwise.
//
// This function is horribly inefficient to implement with decNumber because
// the digits are stored least significant first, which requires moving all
// existing digits down one to make space for the new one to be appended.
//
void
DigitList::append(char digit)
{
    U_ASSERT(digit>='0' && digit<='9');
    // Ignore digits which exceed the precision we can represent
    //    And don't fix for larger precision.  Fix callers instead.
    if (decNumberIsZero(fDecNumber)) {
        // Zero needs to be special cased because of the difference in the way
        // that the old DigitList and decNumber represent it.
        // digit cout was zero for digitList, is one for decNumber
        fDecNumber->lsu[0] = digit & 0x0f;
        fDecNumber->digits = 1;
        fDecNumber->exponent--;     // To match the old digit list implementation.
    } else {
        int32_t nDigits = fDecNumber->digits;
        if (nDigits < fContext.digits) {
            int i;
            for (i=nDigits; i>0; i--) {
                fDecNumber->lsu[i] = fDecNumber->lsu[i-1];
            }
            fDecNumber->lsu[0] = digit & 0x0f;
            fDecNumber->digits++;
            // DigitList emulation - appending doesn't change the magnitude of existing
            //                       digits.  With decNumber's decimal being after the
            //                       least signficant digit, we need to adjust the exponent.
            fDecNumber->exponent--;
        }
    }
    internalClear();
}

static DEC_TYPE
IEEE_FUNCTION_NAME (DEC_TYPE x)
{
  decContext context;
  decNumber dn_result;
  DEC_TYPE result;
  decNumber dn_x;

  FUNC_CONVERT_TO_DN(&x, &dn_x);
  if (decNumberIsNaN (&dn_x))
    return x+x;
  if (decNumberIsZero (&dn_x))	/*  If x == 0: Pole Error */
    {
      DFP_EXCEPT (FE_DIVBYZERO);
      return -DFP_HUGE_VAL;
    }
  if (decNumberIsNegative (&dn_x))	/*  If x < 0,: Domain Error */
    {
      DFP_EXCEPT (FE_INVALID);
      return DFP_NAN;
    }
  if (decNumberIsInfinite (&dn_x))
    return x;

  decContextDefault (&context, DEFAULT_CONTEXT);
  decNumberLn(&dn_result, &dn_x, &context);

  FUNC_CONVERT_FROM_DN(&dn_result, &result, &context);

  return result;
}

/* Compute a factorial.
 * Currently, only for positive integer arguments.  Needs to be extended
 * to a full gamma function.
 */
decNumber *decNumberFactorial(decNumber *r, const decNumber *x, decContext *ctx) {
	decNumber y, const_1;

	int_to_dn(&const_1, 1, ctx);
	decNumberCopy(&y, x);
	if (!decNumberIsNegative(x) || decNumberIsZero(x)) {
		decNumberCopy(r, &const_1);
		for (;;) {
			if (decNumberIsZero(&y))
				break;
			if (decNumberIsInfinite(r))
				break;
			decNumberMultiply(r, r, &y, ctx);
			decNumberSubtract(&y, &y, &const_1, ctx);
		}
	}
	return r;
}

int32_t
DigitList::getCount() const {
    if (decNumberIsZero(fDecNumber) && fDecNumber->exponent==0) {
       // The extra test for exponent==0 is needed because parsing sometimes appends
       // zero digits.  It's bogus, decimalFormatter parsing needs to be cleaned up.
       return 0;
    } else {
       return fDecNumber->digits;
    }
}

static DEC_TYPE
IEEE_FUNCTION_NAME (DEC_TYPE x)
{
  decContext context;
  decNumber dn_result;
  DEC_TYPE result, one, temp;
  decNumber dn_x, dn_temp, dn_one;
/*  int comp;*/

  one=DFP_CONSTANT(1.0);
  FUNC_CONVERT_TO_DN (&one, &dn_one);
  FUNC_CONVERT_TO_DN (&x, &dn_x);

  /*  Handle NaN and early exit for x==0 */
  if (decNumberIsNaN (&dn_x) || decNumberIsZero (&dn_x))
    return x + x;

  decContextDefault (&context, DEFAULT_CONTEXT);
  decNumberAbs (&dn_temp, &dn_x, &context);

  FUNC_CONVERT_FROM_DN (&dn_temp, &temp, &context);
  if(temp==one) {
	/*  |x| == 1 -> Pole Error */
	DFP_EXCEPT (FE_DIVBYZERO);
	return decNumberIsNegative(&dn_x) ? -DFP_HUGE_VAL:DFP_HUGE_VAL;
  } else if (temp>one) {
	/*  |x| > 1 -> Domain Error (this handles +-Inf too) */
	DFP_EXCEPT (FE_INVALID);
	return DFP_NAN;
  }

//  comp = decCompare (&dn_temp, &dn_one);
//  switch (comp)
//    {
//      case 0: /*  |x| == 1 -> Pole Error */
//	DFP_EXCEPT (FE_DIVBYZERO);
//	return decNumberIsNegative(&dn_x) ? -DFP_HUGE_VAL:DFP_HUGE_VAL;
//      case 1: /*  |x| > 1 -> Domain Error (this handles +-Inf too) */
//	DFP_EXCEPT (FE_INVALID);
//	return DFP_NAN;
//    }

  /* Using trig identity: atanh(x) = 1/2 * log((1+x)/(1-x)) */
  decNumberAdd (&dn_result, &dn_one, &dn_x, &context);
  decNumberSubtract (&dn_temp, &dn_one, &dn_x, &context);
  decNumberDivide (&dn_result, &dn_result, &dn_temp, &context);
  decNumberLn (&dn_result, &dn_result, &context);
  decNumberAdd (&dn_temp, &dn_one, &dn_one, &context); /* 2 */
  decNumberDivide (&dn_result, &dn_result, &dn_temp, &context);

  FUNC_CONVERT_FROM_DN (&dn_result, &result, &context);

  return result;
}

static DEC_TYPE
IEEE_FUNCTION_NAME (DEC_TYPE x)
{
  decContext context;
  decNumber dn_result;
  DEC_TYPE result;
  decNumber dn_x;
  decNumber dn_sum;
  decNumber dn_one;
  DEC_TYPE one = DFP_CONSTANT(1.0);

  FUNC_CONVERT_TO_DN (&x, &dn_x);
  FUNC_CONVERT_TO_DN (&one, &dn_one);

  /*  For NaN, 0, or +Inf, just return x */
  if (decNumberIsNaN (&dn_x) || decNumberIsZero (&dn_x) ||
	(decNumberIsInfinite (&dn_x) && !decNumberIsNegative (&dn_x)))
    return x+x;

  decContextDefault(&context, DEFAULT_CONTEXT);
  decNumberAdd(&dn_sum, &dn_x, &dn_one, &context);
  if (decNumberIsZero(&dn_sum)) /*  Pole Error if x was -1 */
    {
      DFP_EXCEPT (FE_DIVBYZERO);
      return -DFP_HUGE_VAL;
    }
  if (decNumberIsNegative(&dn_sum)) /*  Domain Error if x < -1 */
    {
      DFP_EXCEPT (FE_INVALID);
      return DFP_NAN;
    }

  decNumberLn(&dn_result, &dn_sum, &context);
  FUNC_CONVERT_FROM_DN(&dn_result, &result, &context);


  return result;
}

// -------------------------------------
//      comparison function.   Returns
//         Not Comparable :  -2
//                      < :  -1
//                     == :   0
//                      > :  +1
int32_t DigitList::compare(const DigitList &other) {
    decNumber   result;
    int32_t     savedDigits = fContext.digits;
    fContext.digits = 1;
    uprv_decNumberCompare(&result, this->fDecNumber, other.fDecNumber, &fContext);
    fContext.digits = savedDigits;
    if (decNumberIsZero(&result)) {
        return 0;
    } else if (decNumberIsSpecial(&result)) {
        return -2;
    } else if (result.bits & DECNEG) {
        return -1;
    } else {
        return 1;
    }
}

UBool
DigitList::operator==(const DigitList& that) const
{
    if (this == &that) {
        return TRUE;
    }
    decNumber n;  // Has space for only a none digit value.
    decContext c;
    uprv_decContextDefault(&c, DEC_INIT_BASE);
    c.digits = 1;
    c.traps = 0;

    uprv_decNumberCompare(&n, this->fDecNumber, that.fDecNumber, &c);
    UBool result = decNumberIsZero(&n);
    return result;
}

int
PREFIXED_FUNCTION_NAME (DEC_TYPE x, DEC_TYPE y)
{
  decNumber dn_x, dn_y, result;
  decContext context;
  decContextDefault(&context, DEFAULT_CONTEXT);

  FUNC_CONVERT_TO_DN(&x, &dn_x);
  FUNC_CONVERT_TO_DN(&y, &dn_y);

  if(decNumberIsNaN(&dn_x) || decNumberIsNaN(&dn_y))
    return -1;

  decNumberCompare(&result, &dn_x, &dn_y, &context);
  return !decNumberIsNegative(&result) && !decNumberIsZero(&result);
}

int
INTERNAL_FUNCTION_NAME (DEC_TYPE x, DEC_TYPE y)
{
  decNumber dn_x;
  decNumber dn_y;
  decNumber dn_result;
  decContext context;

  FUNC_CONVERT_TO_DN(&x, &dn_x);
  FUNC_CONVERT_TO_DN(&y, &dn_y);

  if(decNumberIsNaN(&dn_x) || decNumberIsNaN(&dn_y))
    return 0;

  decNumberCompare (&dn_result, &dn_x, &dn_y, &context);
  return (-decNumberIsNegative (&dn_result)) ||
	 (!decNumberIsNegative (&dn_result) && !decNumberIsZero (&dn_result));
}