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/*
* Copyright (C) 2012 Google 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:
*
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * 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.
* * Neither the name of Google Inc. nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "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 THE COPYRIGHT
* OWNER 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 Decimal_h
#define Decimal_h
#include <stdint.h>
#include <wtf/Assertions.h>
#include <wtf/text/WTFString.h>
namespace WebCore {
namespace DecimalPrivate {
class SpecialValueHandler;
}
// This class represents decimal base floating point number.
//
// FIXME: Once all C++ compiler support decimal type, we should replace this
// class to compiler supported one. See below URI for current status of decimal
// type for C++: // http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2006/n1977.html
class Decimal {
WTF_MAKE_FAST_ALLOCATED;
public:
enum Sign {
Positive,
Negative,
};
// You should not use EncodedData other than unit testing.
class EncodedData {
// For accessing FormatClass.
friend class Decimal;
friend class DecimalPrivate::SpecialValueHandler;
public:
EncodedData(Sign, int exponent, uint64_t coefficient);
bool operator==(const EncodedData&) const;
bool operator!=(const EncodedData& another) const { return !operator==(another); }
uint64_t coefficient() const { return m_coefficient; }
int countDigits() const;
int exponent() const { return m_exponent; }
bool isFinite() const { return !isSpecial(); }
bool isInfinity() const { return m_formatClass == ClassInfinity; }
bool isNaN() const { return m_formatClass == ClassNaN; }
bool isSpecial() const { return m_formatClass == ClassInfinity || m_formatClass == ClassNaN; }
bool isZero() const { return m_formatClass == ClassZero; }
Sign sign() const { return m_sign; }
void setSign(Sign sign) { m_sign = sign; }
private:
enum FormatClass {
ClassInfinity,
ClassNormal,
ClassNaN,
ClassZero,
};
EncodedData(Sign, FormatClass);
FormatClass formatClass() const { return m_formatClass; }
uint64_t m_coefficient;
int16_t m_exponent;
FormatClass m_formatClass;
Sign m_sign;
};
Decimal(int32_t = 0);
Decimal(Sign, int exponent, uint64_t coefficient);
Decimal(const Decimal&);
Decimal& operator=(const Decimal&);
Decimal& operator+=(const Decimal&);
Decimal& operator-=(const Decimal&);
Decimal& operator*=(const Decimal&);
Decimal& operator/=(const Decimal&);
Decimal operator-() const;
bool operator==(const Decimal&) const;
bool operator!=(const Decimal&) const;
bool operator<(const Decimal&) const;
bool operator<=(const Decimal&) const;
bool operator>(const Decimal&) const;
bool operator>=(const Decimal&) const;
Decimal operator+(const Decimal&) const;
Decimal operator-(const Decimal&) const;
Decimal operator*(const Decimal&) const;
Decimal operator/(const Decimal&) const;
int exponent() const
{
ASSERT(isFinite());
return m_data.exponent();
}
bool isFinite() const { return m_data.isFinite(); }
bool isInfinity() const { return m_data.isInfinity(); }
bool isNaN() const { return m_data.isNaN(); }
bool isNegative() const { return sign() == Negative; }
bool isPositive() const { return sign() == Positive; }
bool isSpecial() const { return m_data.isSpecial(); }
bool isZero() const { return m_data.isZero(); }
Decimal abs() const;
Decimal ceiling() const;
Decimal floor() const;
Decimal remainder(const Decimal&) const;
Decimal round() const;
double toDouble() const;
// Note: toString method supports infinity and nan but fromString not.
String toString() const;
static Decimal fromDouble(double);
// fromString supports following syntax EBNF:
// number ::= sign? digit+ ('.' digit*) (exponent-marker sign? digit+)?
// | sign? '.' digit+ (exponent-marker sign? digit+)?
// sign ::= '+' | '-'
// exponent-marker ::= 'e' | 'E'
// digit ::= '0' | '1' | ... | '9'
// Note: fromString doesn't support "infinity" and "nan".
static Decimal fromString(const String&);
static Decimal infinity(Sign);
static Decimal nan();
static Decimal zero(Sign);
// You should not use below methods. We expose them for unit testing.
explicit Decimal(const EncodedData&);
const EncodedData& value() const { return m_data; }
private:
struct AlignedOperands {
uint64_t lhsCoefficient;
uint64_t rhsCoefficient;
int exponent;
};
Decimal(double);
Decimal compareTo(const Decimal&) const;
static AlignedOperands alignOperands(const Decimal& lhs, const Decimal& rhs);
static inline Sign invertSign(Sign sign) { return sign == Negative ? Positive : Negative; }
Sign sign() const { return m_data.sign(); }
EncodedData m_data;
};
} // namespace WebCore
#endif // Decimal_h
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