Decimal.h (9680B)
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 */ 30 31 /** 32 * Imported from: 33 * https://chromium.googlesource.com/chromium/src.git/+/master/third_party/WebKit/Source/platform/Decimal.h 34 * Check UPSTREAM-GIT-SHA for the commit ID of the last update from Blink core. 35 */ 36 37 #ifndef Decimal_h 38 #define Decimal_h 39 40 #include "mozilla/Assertions.h" 41 #include <stdint.h> 42 #include "mozilla/Types.h" 43 44 #include <string> 45 46 #ifndef ASSERT 47 #define DEFINED_ASSERT_FOR_DECIMAL_H 1 48 #define ASSERT MOZ_ASSERT 49 #endif 50 51 #define PLATFORM_EXPORT 52 53 // To use USING_FAST_MALLOC we'd need: 54 // https://chromium.googlesource.com/chromium/src.git/+/master/third_party/WebKit/Source/wtf/Allocator.h 55 // Since we don't allocate Decimal objects, no need. 56 #define USING_FAST_MALLOC(type) \ 57 void ignore_this_dummy_method() = delete 58 59 #define DISALLOW_NEW() \ 60 private: \ 61 void* operator new(size_t) = delete; \ 62 void* operator new(size_t, void*) = delete; \ 63 public: 64 65 namespace blink { 66 67 namespace DecimalPrivate { 68 constexpr int ExponentMax = 1023; 69 constexpr int ExponentMin = -1023; 70 constexpr int Precision = 18; 71 72 static const uint64_t MaxCoefficient = UINT64_C(0xDE0B6B3A763FFFF); // 999999999999999999 == 18 9's 73 class SpecialValueHandler; 74 } 75 76 struct DecimalLiteral { 77 int32_t value; 78 friend constexpr DecimalLiteral operator*(int32_t lhs, DecimalLiteral rhs) { 79 return {lhs * rhs.value}; 80 } 81 constexpr DecimalLiteral operator-() { 82 return {-value}; 83 } 84 }; 85 86 constexpr DecimalLiteral operator""_d(unsigned long long value) { 87 return {static_cast<int32_t>(value)}; 88 } 89 90 // This class represents decimal base floating point number. 91 // 92 // FIXME: Once all C++ compiler support decimal type, we should replace this 93 // class to compiler supported one. See below URI for current status of decimal 94 // type for C++: // http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2006/n1977.html 95 class PLATFORM_EXPORT Decimal { 96 USING_FAST_MALLOC(Decimal); 97 public: 98 enum Sign { 99 Positive, 100 Negative, 101 }; 102 103 // You should not use EncodedData other than unit testing. 104 class EncodedData { 105 DISALLOW_NEW(); 106 // For accessing FormatClass. 107 friend class Decimal; 108 friend class DecimalPrivate::SpecialValueHandler; 109 public: 110 constexpr EncodedData(Sign sign, int exponent, uint64_t coefficient) 111 : m_coefficient(0), 112 m_exponent(0), 113 m_formatClass(coefficient ? ClassNormal : ClassZero), 114 m_sign(sign) { 115 if (exponent >= DecimalPrivate::ExponentMin && 116 exponent <= DecimalPrivate::ExponentMax) { 117 while (coefficient > DecimalPrivate::MaxCoefficient) { 118 coefficient /= 10; 119 ++exponent; 120 } 121 } 122 123 if (exponent > DecimalPrivate::ExponentMax) { 124 m_formatClass = ClassInfinity; 125 return; 126 } 127 128 if (exponent < DecimalPrivate::ExponentMin) { 129 m_formatClass = ClassZero; 130 return; 131 } 132 133 m_coefficient = coefficient; 134 m_exponent = static_cast<int16_t>(exponent); 135 } 136 137 bool operator==(const EncodedData&) const; 138 bool operator!=(const EncodedData& another) const { return !operator==(another); } 139 140 uint64_t coefficient() const { return m_coefficient; } 141 int countDigits() const; 142 int exponent() const { return m_exponent; } 143 bool isFinite() const { return !isSpecial(); } 144 bool isInfinity() const { return m_formatClass == ClassInfinity; } 145 bool isNaN() const { return m_formatClass == ClassNaN; } 146 bool isSpecial() const { return m_formatClass == ClassInfinity || m_formatClass == ClassNaN; } 147 bool isZero() const { return m_formatClass == ClassZero; } 148 Sign sign() const { return m_sign; } 149 void setSign(Sign sign) { m_sign = sign; } 150 151 private: 152 enum FormatClass { 153 ClassInfinity, 154 ClassNormal, 155 ClassNaN, 156 ClassZero, 157 }; 158 159 constexpr EncodedData(Sign sign, FormatClass formatClass) 160 : m_coefficient(0), 161 m_exponent(0), 162 m_formatClass(formatClass), 163 m_sign(sign) {} 164 165 FormatClass formatClass() const { return m_formatClass; } 166 167 uint64_t m_coefficient; 168 int16_t m_exponent; 169 FormatClass m_formatClass; 170 Sign m_sign; 171 }; 172 173 constexpr explicit Decimal(DecimalLiteral i32) 174 : m_data(i32.value < 0 ? Negative : Positive, 0, 175 i32.value < 0 ? static_cast<uint64_t>(-static_cast<int64_t>(i32.value)) 176 : static_cast<uint64_t>(i32.value)) {} 177 178 MFBT_API explicit Decimal(int32_t i32 = 0); 179 MFBT_API Decimal(Sign sign, int exponent, uint64_t coefficient); 180 MFBT_API Decimal(const Decimal&); 181 182 MFBT_API Decimal& operator=(const Decimal&); 183 MFBT_API Decimal& operator+=(const Decimal&); 184 MFBT_API Decimal& operator-=(const Decimal&); 185 MFBT_API Decimal& operator*=(const Decimal&); 186 MFBT_API Decimal& operator/=(const Decimal&); 187 188 MFBT_API Decimal operator-() const; 189 190 MFBT_API bool operator==(const Decimal&) const; 191 MFBT_API bool operator!=(const Decimal&) const; 192 MFBT_API bool operator<(const Decimal&) const; 193 MFBT_API bool operator<=(const Decimal&) const; 194 MFBT_API bool operator>(const Decimal&) const; 195 MFBT_API bool operator>=(const Decimal&) const; 196 197 MFBT_API Decimal operator+(const Decimal&) const; 198 MFBT_API Decimal operator-(const Decimal&) const; 199 MFBT_API Decimal operator*(const Decimal&) const; 200 MFBT_API Decimal operator/(const Decimal&) const; 201 202 int exponent() const 203 { 204 ASSERT(isFinite()); 205 return m_data.exponent(); 206 } 207 208 bool isFinite() const { return m_data.isFinite(); } 209 bool isInfinity() const { return m_data.isInfinity(); } 210 bool isNaN() const { return m_data.isNaN(); } 211 bool isNegative() const { return sign() == Negative; } 212 bool isPositive() const { return sign() == Positive; } 213 bool isSpecial() const { return m_data.isSpecial(); } 214 bool isZero() const { return m_data.isZero(); } 215 216 MFBT_API Decimal abs() const; 217 MFBT_API Decimal ceil() const; 218 MFBT_API Decimal floor() const; 219 MFBT_API Decimal remainder(const Decimal&) const; 220 MFBT_API Decimal round() const; 221 222 MFBT_API double toDouble() const; 223 // Note: toString method supports infinity and nan but fromString not. 224 MFBT_API std::string toString() const; 225 226 static MFBT_API Decimal fromDouble(double); 227 // fromString supports following syntax EBNF: 228 // number ::= sign? digit+ ('.' digit*) (exponent-marker sign? digit+)? 229 // | sign? '.' digit+ (exponent-marker sign? digit+)? 230 // sign ::= '+' | '-' 231 // exponent-marker ::= 'e' | 'E' 232 // digit ::= '0' | '1' | ... | '9' 233 // Note: fromString doesn't support "infinity" and "nan". 234 static MFBT_API Decimal fromString(const std::string& aValue); 235 static MFBT_API Decimal infinity(Sign); 236 static constexpr Decimal nan() { 237 return Decimal(EncodedData(Positive, EncodedData::ClassNaN)); 238 } 239 static MFBT_API Decimal zero(Sign); 240 241 // You should not use below methods. We expose them for unit testing. 242 constexpr explicit Decimal(const EncodedData& data) : m_data(data) {} 243 const EncodedData& value() const { return m_data; } 244 245 private: 246 struct AlignedOperands { 247 uint64_t lhsCoefficient; 248 uint64_t rhsCoefficient; 249 int exponent; 250 }; 251 252 MFBT_API explicit Decimal(double); 253 MFBT_API Decimal compareTo(const Decimal&) const; 254 255 static MFBT_API AlignedOperands alignOperands(const Decimal& lhs, const Decimal& rhs); 256 static inline Sign invertSign(Sign sign) { return sign == Negative ? Positive : Negative; } 257 258 Sign sign() const { return m_data.sign(); } 259 260 EncodedData m_data; 261 }; 262 263 } // namespace blink 264 265 namespace mozilla { 266 typedef blink::Decimal Decimal; 267 using blink::operator""_d; 268 } // namespace mozilla 269 270 #undef USING_FAST_MALLOC 271 272 #ifdef DEFINED_ASSERT_FOR_DECIMAL_H 273 #undef DEFINED_ASSERT_FOR_DECIMAL_H 274 #undef ASSERT 275 #endif 276 277 #endif // Decimal_h