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/*
* Copyright (C) 2010 Apple Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
* OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#ifndef DecimalNumber_h
#define DecimalNumber_h
#include <math.h>
#include <wtf/dtoa.h>
#include <wtf/MathExtras.h>
#include <wtf/text/WTFString.h>
namespace WTF {
enum RoundingSignificantFiguresType { RoundingSignificantFigures };
enum RoundingDecimalPlacesType { RoundingDecimalPlaces };
class DecimalNumber {
public:
DecimalNumber(double d)
{
ASSERT(!isnan(d) && !isinf(d));
dtoa(m_significand, d, m_sign, m_exponent, m_precision);
ASSERT(m_precision);
// Zero should always have exponent 0.
ASSERT(m_significand[0] != '0' || !m_exponent);
// No values other than zero should have a leading zero.
ASSERT(m_significand[0] != '0' || m_precision == 1);
// No values other than zero should have trailing zeros.
ASSERT(m_significand[0] == '0' || m_significand[m_precision - 1] != '0');
}
DecimalNumber(double d, RoundingSignificantFiguresType, unsigned significantFigures)
{
ASSERT(!isnan(d) && !isinf(d));
dtoaRoundSF(m_significand, d, significantFigures, m_sign, m_exponent, m_precision);
ASSERT(significantFigures && significantFigures <= sizeof(DtoaBuffer));
while (m_precision < significantFigures)
m_significand[m_precision++] = '0';
ASSERT(m_precision);
// Zero should always have exponent 0.
ASSERT(m_significand[0] != '0' || !m_exponent);
}
DecimalNumber(double d, RoundingDecimalPlacesType, unsigned decimalPlaces)
{
ASSERT(!isnan(d) && !isinf(d));
dtoaRoundDP(m_significand, d, decimalPlaces, m_sign, m_exponent, m_precision);
unsigned significantFigures = 1 + m_exponent + decimalPlaces;
ASSERT(significantFigures && significantFigures <= sizeof(DtoaBuffer));
while (m_precision < significantFigures)
m_significand[m_precision++] = '0';
ASSERT(m_precision);
// Zero should always have exponent 0.
ASSERT(m_significand[0] != '0' || !m_exponent);
}
unsigned toStringDecimal(NumberToStringBuffer buffer)
{
// Should always be at least one digit to add to the string!
ASSERT(m_precision);
UChar* next = buffer;
// if the exponent is negative the number decimal representation is of the form:
// [<sign>]0.[<zeros>]<significand>
if (m_exponent < 0) {
unsigned zeros = -m_exponent - 1;
if (m_sign)
*next++ = '-';
*next++ = '0';
*next++ = '.';
for (unsigned i = 0; i < zeros; ++i)
*next++ = '0';
for (unsigned i = 0; i < m_precision; ++i)
*next++ = m_significand[i];
return next - buffer;
}
unsigned digitsBeforeDecimalPoint = m_exponent + 1;
// If the precision is <= than the number of digits to get up to the decimal
// point, then there is no fractional part, number is of the form:
// [<sign>]<significand>[<zeros>]
if (m_precision <= digitsBeforeDecimalPoint) {
if (m_sign)
*next++ = '-';
for (unsigned i = 0; i < m_precision; ++i)
*next++ = m_significand[i];
for (unsigned i = 0; i < (digitsBeforeDecimalPoint - m_precision); ++i)
*next++ = '0';
return next - buffer;
}
// If we get here, number starts before the decimal point, and ends after it,
// as such is of the form:
// [<sign>]<significand-begin>.<significand-end>
if (m_sign)
*next++ = '-';
for (unsigned i = 0; i < digitsBeforeDecimalPoint; ++i)
*next++ = m_significand[i];
*next++ = '.';
for (unsigned i = digitsBeforeDecimalPoint; i < m_precision; ++i)
*next++ = m_significand[i];
return next - buffer;
}
unsigned toStringExponential(NumberToStringBuffer buffer)
{
// Should always be at least one digit to add to the string!
ASSERT(m_precision);
UChar* next = buffer;
// Add the sign
if (m_sign)
*next++ = '-';
// Add the significand
*next++ = m_significand[0];
if (m_precision > 1) {
*next++ = '.';
for (unsigned i = 1; i < m_precision; ++i)
*next++ = m_significand[i];
}
// Add "e+" or "e-"
*next++ = 'e';
int exponent;
if (m_exponent >= 0) {
*next++ = '+';
exponent = m_exponent;
} else {
*next++ = '-';
exponent = -m_exponent;
}
// Add the exponent
if (exponent >= 100)
*next++ = '0' + exponent / 100;
if (exponent >= 10)
*next++ = '0' + (exponent % 100) / 10;
*next++ = '0' + exponent % 10;
return next - buffer;
}
bool sign() { return m_sign; }
int exponent() { return m_exponent; }
const char* significand() { return m_significand; } // significand contains precision characters, is not null-terminated.
unsigned precision() { return m_precision; }
private:
bool m_sign;
int m_exponent;
DtoaBuffer m_significand;
unsigned m_precision;
};
} // namespace WTF
using WTF::DecimalNumber;
using WTF::RoundingSignificantFigures;
using WTF::RoundingDecimalPlaces;
#endif // DecimalNumber_h
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