The Tor Browser: mfbt/decimal/Decimal.h@fc2d59ddac77

     1 /*

     2  * Copyright (C) 2012 Google Inc. All rights reserved.

     3  *

     4  * Redistribution and use in source and binary forms, with or without

     5  * modification, are permitted provided that the following conditions are

     6  * met:

     7  *

     8  *     * Redistributions of source code must retain the above copyright

     9  * notice, this list of conditions and the following disclaimer.

    10  *     * Redistributions in binary form must reproduce the above

    11  * copyright notice, this list of conditions and the following disclaimer

    12  * in the documentation and/or other materials provided with the

    13  * distribution.

    14  *     * Neither the name of Google Inc. nor the names of its

    15  * contributors may be used to endorse or promote products derived from

    16  * this software without specific prior written permission.

    17  *

    18  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS

    19  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT

    20  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR

    21  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT

    22  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,

    23  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT

    24  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,

    25  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY

    26  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT

    27  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE

    28  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

    29  */

    31 /**

    32  * Imported from:

    33  * http://src.chromium.org/viewvc/blink/trunk/Source/core/platform/Decimal.h

    34  * Check hg log for the svn rev of the last update from Blink core.

    35  */

    37 #ifndef Decimal_h

    38 #define Decimal_h

    40 #include "mozilla/Assertions.h"

    41 #include <stdint.h>

    42 #include "mozilla/Types.h"

    44 #include <string>

    46 #ifndef ASSERT

    47 #define DEFINED_ASSERT_FOR_DECIMAL_H 1

    48 #define ASSERT MOZ_ASSERT

    49 #endif

    51 // To use WTF_MAKE_FAST_ALLOCATED we'd need:

    52 // http://src.chromium.org/viewvc/blink/trunk/Source/wtf/FastMalloc.h

    53 // Since we don't allocate Decimal objects, no need.

    54 #define WTF_MAKE_FAST_ALLOCATED \

    55   void ignore_this_dummy_method() MOZ_DELETE

    57 namespace WebCore {

    59 namespace DecimalPrivate {

    60 class SpecialValueHandler;

    61 }

    63 // This class represents decimal base floating point number.

    64 //

    65 // FIXME: Once all C++ compiler support decimal type, we should replace this

    66 // class to compiler supported one. See below URI for current status of decimal

    67 // type for C++: // http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2006/n1977.html

    68 class Decimal {

    69     WTF_MAKE_FAST_ALLOCATED;

    70 public:

    71     enum Sign {

    72         Positive,

    73         Negative,

    74     };

    76     // You should not use EncodedData other than unit testing.

    77     class EncodedData {

    78         // For accessing FormatClass.

    79         friend class Decimal;

    80         friend class DecimalPrivate::SpecialValueHandler;

    81     public:

    82         EncodedData(Sign, int exponent, uint64_t coefficient);

    84         bool operator==(const EncodedData&) const;

    85         bool operator!=(const EncodedData& another) const { return !operator==(another); }

    87         uint64_t coefficient() const { return m_coefficient; }

    88         int countDigits() const;

    89         int exponent() const { return m_exponent; }

    90         bool isFinite() const { return !isSpecial(); }

    91         bool isInfinity() const { return m_formatClass == ClassInfinity; }

    92         bool isNaN() const { return m_formatClass == ClassNaN; }

    93         bool isSpecial() const { return m_formatClass == ClassInfinity || m_formatClass == ClassNaN; }

    94         bool isZero() const { return m_formatClass == ClassZero; }

    95         Sign sign() const { return m_sign; }

    96         void setSign(Sign sign) { m_sign = sign; }

    98     private:

    99         enum FormatClass {

   100             ClassInfinity,

   101             ClassNormal,

   102             ClassNaN,

   103             ClassZero,

   104         };

   106         EncodedData(Sign, FormatClass);

   107         FormatClass formatClass() const { return m_formatClass; }

   109         uint64_t m_coefficient;

   110         int16_t m_exponent;

   111         FormatClass m_formatClass;

   112         Sign m_sign;

   113     };

   115     MFBT_API Decimal(int32_t = 0);

   116     MFBT_API Decimal(Sign, int exponent, uint64_t coefficient);

   117     MFBT_API Decimal(const Decimal&);

   119     MFBT_API Decimal& operator=(const Decimal&);

   120     MFBT_API Decimal& operator+=(const Decimal&);

   121     MFBT_API Decimal& operator-=(const Decimal&);

   122     MFBT_API Decimal& operator*=(const Decimal&);

   123     MFBT_API Decimal& operator/=(const Decimal&);

   125     MFBT_API Decimal operator-() const;

   127     MFBT_API bool operator==(const Decimal&) const;

   128     MFBT_API bool operator!=(const Decimal&) const;

   129     MFBT_API bool operator<(const Decimal&) const;

   130     MFBT_API bool operator<=(const Decimal&) const;

   131     MFBT_API bool operator>(const Decimal&) const;

   132     MFBT_API bool operator>=(const Decimal&) const;

   134     MFBT_API Decimal operator+(const Decimal&) const;

   135     MFBT_API Decimal operator-(const Decimal&) const;

   136     MFBT_API Decimal operator*(const Decimal&) const;

   137     MFBT_API Decimal operator/(const Decimal&) const;

   139     int exponent() const

   140     {

   141         ASSERT(isFinite());

   142         return m_data.exponent();

   143     }

   145     bool isFinite() const { return m_data.isFinite(); }

   146     bool isInfinity() const { return m_data.isInfinity(); }

   147     bool isNaN() const { return m_data.isNaN(); }

   148     bool isNegative() const { return sign() == Negative; }

   149     bool isPositive() const { return sign() == Positive; }

   150     bool isSpecial() const { return m_data.isSpecial(); }

   151     bool isZero() const { return m_data.isZero(); }

   153     MFBT_API Decimal abs() const;

   154     MFBT_API Decimal ceiling() const;

   155     MFBT_API Decimal floor() const;

   156     MFBT_API Decimal remainder(const Decimal&) const;

   157     MFBT_API Decimal round() const;

   159     MFBT_API double toDouble() const;

   160     // Note: toString method supports infinity and nan but fromString not.

   161     MFBT_API std::string toString() const;

   162     MFBT_API bool toString(char* strBuf, size_t bufLength) const;

   164     static MFBT_API Decimal fromDouble(double);

   165     // fromString supports following syntax EBNF:

   166     //  number ::= sign? digit+ ('.' digit*) (exponent-marker sign? digit+)?

   167     //          | sign? '.' digit+ (exponent-marker sign? digit+)?

   168     //  sign ::= '+' | '-'

   169     //  exponent-marker ::= 'e' | 'E'

   170     //  digit ::= '0' | '1' | ... | '9'

   171     // Note: fromString doesn't support "infinity" and "nan".

   172     static MFBT_API Decimal fromString(const std::string& aValue);

   173     static MFBT_API Decimal infinity(Sign);

   174     static MFBT_API Decimal nan();

   175     static MFBT_API Decimal zero(Sign);

   177     // You should not use below methods. We expose them for unit testing.

   178     MFBT_API explicit Decimal(const EncodedData&);

   179     const EncodedData& value() const { return m_data; }

   181 private:

   182     struct AlignedOperands {

   183         uint64_t lhsCoefficient;

   184         uint64_t rhsCoefficient;

   185         int exponent;

   186     };

   188     MFBT_API Decimal(double);

   189     MFBT_API Decimal compareTo(const Decimal&) const;

   191     static MFBT_API AlignedOperands alignOperands(const Decimal& lhs, const Decimal& rhs);

   192     static inline Sign invertSign(Sign sign) { return sign == Negative ? Positive : Negative; }

   194     Sign sign() const { return m_data.sign(); }

   196     EncodedData m_data;

   197 };

   199 } // namespace WebCore

   201 namespace mozilla {

   202   typedef WebCore::Decimal Decimal;

   203 }

   205 #undef WTF_MAKE_FAST_ALLOCATED

   207 #ifdef DEFINED_ASSERT_FOR_DECIMAL_H

   208 #undef DEFINED_ASSERT_FOR_DECIMAL_H

   209 #undef ASSERT

   210 #endif

   212 #endif // Decimal_h

The Tor Browser / file revision

mfbt/decimal/Decimal.h@fc2d59ddac77

mfbt/decimal/Decimal.h