1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/mfbt/decimal/Decimal.cpp Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,1056 @@
1.4 +/*
1.5 + * Copyright (C) 2012 Google Inc. All rights reserved.
1.6 + *
1.7 + * Redistribution and use in source and binary forms, with or without
1.8 + * modification, are permitted provided that the following conditions are
1.9 + * met:
1.10 + *
1.11 + * * Redistributions of source code must retain the above copyright
1.12 + * notice, this list of conditions and the following disclaimer.
1.13 + * * Redistributions in binary form must reproduce the above
1.14 + * copyright notice, this list of conditions and the following disclaimer
1.15 + * in the documentation and/or other materials provided with the
1.16 + * distribution.
1.17 + * * Neither the name of Google Inc. nor the names of its
1.18 + * contributors may be used to endorse or promote products derived from
1.19 + * this software without specific prior written permission.
1.20 + *
1.21 + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
1.22 + * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
1.23 + * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
1.24 + * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
1.25 + * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
1.26 + * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
1.27 + * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
1.28 + * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
1.29 + * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
1.30 + * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
1.31 + * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
1.32 + */
1.33 +
1.34 +#include "Decimal.h"
1.35 +#include "moz-decimal-utils.h"
1.36 +
1.37 +#include <algorithm>
1.38 +#include <float.h>
1.39 +
1.40 +using namespace moz_decimal_utils;
1.41 +
1.42 +namespace WebCore {
1.43 +
1.44 +namespace DecimalPrivate {
1.45 +
1.46 +static int const ExponentMax = 1023;
1.47 +static int const ExponentMin = -1023;
1.48 +static int const Precision = 18;
1.49 +
1.50 +static const uint64_t MaxCoefficient = UINT64_C(0x16345785D89FFFF); // 999999999999999999 == 18 9's
1.51 +
1.52 +// This class handles Decimal special values.
1.53 +class SpecialValueHandler {
1.54 + WTF_MAKE_NONCOPYABLE(SpecialValueHandler);
1.55 +public:
1.56 + enum HandleResult {
1.57 + BothFinite,
1.58 + BothInfinity,
1.59 + EitherNaN,
1.60 + LHSIsInfinity,
1.61 + RHSIsInfinity,
1.62 + };
1.63 +
1.64 + SpecialValueHandler(const Decimal& lhs, const Decimal& rhs);
1.65 + HandleResult handle();
1.66 + Decimal value() const;
1.67 +
1.68 +private:
1.69 + enum Result {
1.70 + ResultIsLHS,
1.71 + ResultIsRHS,
1.72 + ResultIsUnknown,
1.73 + };
1.74 +
1.75 + const Decimal& m_lhs;
1.76 + const Decimal& m_rhs;
1.77 + Result m_result;
1.78 +};
1.79 +
1.80 +SpecialValueHandler::SpecialValueHandler(const Decimal& lhs, const Decimal& rhs)
1.81 + : m_lhs(lhs), m_rhs(rhs), m_result(ResultIsUnknown)
1.82 +{
1.83 +}
1.84 +
1.85 +SpecialValueHandler::HandleResult SpecialValueHandler::handle()
1.86 +{
1.87 + if (m_lhs.isFinite() && m_rhs.isFinite())
1.88 + return BothFinite;
1.89 +
1.90 + const Decimal::EncodedData::FormatClass lhsClass = m_lhs.value().formatClass();
1.91 + const Decimal::EncodedData::FormatClass rhsClass = m_rhs.value().formatClass();
1.92 + if (lhsClass == Decimal::EncodedData::ClassNaN) {
1.93 + m_result = ResultIsLHS;
1.94 + return EitherNaN;
1.95 + }
1.96 +
1.97 + if (rhsClass == Decimal::EncodedData::ClassNaN) {
1.98 + m_result = ResultIsRHS;
1.99 + return EitherNaN;
1.100 + }
1.101 +
1.102 + if (lhsClass == Decimal::EncodedData::ClassInfinity)
1.103 + return rhsClass == Decimal::EncodedData::ClassInfinity ? BothInfinity : LHSIsInfinity;
1.104 +
1.105 + if (rhsClass == Decimal::EncodedData::ClassInfinity)
1.106 + return RHSIsInfinity;
1.107 +
1.108 + ASSERT_NOT_REACHED();
1.109 + return BothFinite;
1.110 +}
1.111 +
1.112 +Decimal SpecialValueHandler::value() const
1.113 +{
1.114 + switch (m_result) {
1.115 + case ResultIsLHS:
1.116 + return m_lhs;
1.117 + case ResultIsRHS:
1.118 + return m_rhs;
1.119 + case ResultIsUnknown:
1.120 + default:
1.121 + ASSERT_NOT_REACHED();
1.122 + return m_lhs;
1.123 + }
1.124 +}
1.125 +
1.126 +// This class is used for 128 bit unsigned integer arithmetic.
1.127 +class UInt128 {
1.128 +public:
1.129 + UInt128(uint64_t low, uint64_t high)
1.130 + : m_high(high), m_low(low)
1.131 + {
1.132 + }
1.133 +
1.134 + UInt128& operator/=(uint32_t);
1.135 +
1.136 + uint64_t high() const { return m_high; }
1.137 + uint64_t low() const { return m_low; }
1.138 +
1.139 + static UInt128 multiply(uint64_t u, uint64_t v) { return UInt128(u * v, multiplyHigh(u, v)); }
1.140 +
1.141 +private:
1.142 + static uint32_t highUInt32(uint64_t x) { return static_cast<uint32_t>(x >> 32); }
1.143 + static uint32_t lowUInt32(uint64_t x) { return static_cast<uint32_t>(x & ((static_cast<uint64_t>(1) << 32) - 1)); }
1.144 + bool isZero() const { return !m_low && !m_high; }
1.145 + static uint64_t makeUInt64(uint32_t low, uint32_t high) { return low | (static_cast<uint64_t>(high) << 32); }
1.146 +
1.147 + static uint64_t multiplyHigh(uint64_t, uint64_t);
1.148 +
1.149 + uint64_t m_high;
1.150 + uint64_t m_low;
1.151 +};
1.152 +
1.153 +UInt128& UInt128::operator/=(const uint32_t divisor)
1.154 +{
1.155 + ASSERT(divisor);
1.156 +
1.157 + if (!m_high) {
1.158 + m_low /= divisor;
1.159 + return *this;
1.160 + }
1.161 +
1.162 + uint32_t dividend[4];
1.163 + dividend[0] = lowUInt32(m_low);
1.164 + dividend[1] = highUInt32(m_low);
1.165 + dividend[2] = lowUInt32(m_high);
1.166 + dividend[3] = highUInt32(m_high);
1.167 +
1.168 + uint32_t quotient[4];
1.169 + uint32_t remainder = 0;
1.170 + for (int i = 3; i >= 0; --i) {
1.171 + const uint64_t work = makeUInt64(dividend[i], remainder);
1.172 + remainder = static_cast<uint32_t>(work % divisor);
1.173 + quotient[i] = static_cast<uint32_t>(work / divisor);
1.174 + }
1.175 + m_low = makeUInt64(quotient[0], quotient[1]);
1.176 + m_high = makeUInt64(quotient[2], quotient[3]);
1.177 + return *this;
1.178 +}
1.179 +
1.180 +// Returns high 64bit of 128bit product.
1.181 +uint64_t UInt128::multiplyHigh(uint64_t u, uint64_t v)
1.182 +{
1.183 + const uint64_t uLow = lowUInt32(u);
1.184 + const uint64_t uHigh = highUInt32(u);
1.185 + const uint64_t vLow = lowUInt32(v);
1.186 + const uint64_t vHigh = highUInt32(v);
1.187 + const uint64_t partialProduct = uHigh * vLow + highUInt32(uLow * vLow);
1.188 + return uHigh * vHigh + highUInt32(partialProduct) + highUInt32(uLow * vHigh + lowUInt32(partialProduct));
1.189 +}
1.190 +
1.191 +static int countDigits(uint64_t x)
1.192 +{
1.193 + int numberOfDigits = 0;
1.194 + for (uint64_t powerOfTen = 1; x >= powerOfTen; powerOfTen *= 10) {
1.195 + ++numberOfDigits;
1.196 + if (powerOfTen >= std::numeric_limits<uint64_t>::max() / 10)
1.197 + break;
1.198 + }
1.199 + return numberOfDigits;
1.200 +}
1.201 +
1.202 +static uint64_t scaleDown(uint64_t x, int n)
1.203 +{
1.204 + ASSERT(n >= 0);
1.205 + while (n > 0 && x) {
1.206 + x /= 10;
1.207 + --n;
1.208 + }
1.209 + return x;
1.210 +}
1.211 +
1.212 +static uint64_t scaleUp(uint64_t x, int n)
1.213 +{
1.214 + ASSERT(n >= 0);
1.215 + ASSERT(n < Precision);
1.216 +
1.217 + uint64_t y = 1;
1.218 + uint64_t z = 10;
1.219 + for (;;) {
1.220 + if (n & 1)
1.221 + y = y * z;
1.222 +
1.223 + n >>= 1;
1.224 + if (!n)
1.225 + return x * y;
1.226 +
1.227 + z = z * z;
1.228 + }
1.229 +}
1.230 +
1.231 +} // namespace DecimalPrivate
1.232 +
1.233 +using namespace DecimalPrivate;
1.234 +
1.235 +Decimal::EncodedData::EncodedData(Sign sign, FormatClass formatClass)
1.236 + : m_coefficient(0)
1.237 + , m_exponent(0)
1.238 + , m_formatClass(formatClass)
1.239 + , m_sign(sign)
1.240 +{
1.241 +}
1.242 +
1.243 +Decimal::EncodedData::EncodedData(Sign sign, int exponent, uint64_t coefficient)
1.244 + : m_formatClass(coefficient ? ClassNormal : ClassZero)
1.245 + , m_sign(sign)
1.246 +{
1.247 + if (exponent >= ExponentMin && exponent <= ExponentMax) {
1.248 + while (coefficient > MaxCoefficient) {
1.249 + coefficient /= 10;
1.250 + ++exponent;
1.251 + }
1.252 + }
1.253 +
1.254 + if (exponent > ExponentMax) {
1.255 + m_coefficient = 0;
1.256 + m_exponent = 0;
1.257 + m_formatClass = ClassInfinity;
1.258 + return;
1.259 + }
1.260 +
1.261 + if (exponent < ExponentMin) {
1.262 + m_coefficient = 0;
1.263 + m_exponent = 0;
1.264 + m_formatClass = ClassZero;
1.265 + return;
1.266 + }
1.267 +
1.268 + m_coefficient = coefficient;
1.269 + m_exponent = static_cast<int16_t>(exponent);
1.270 +}
1.271 +
1.272 +bool Decimal::EncodedData::operator==(const EncodedData& another) const
1.273 +{
1.274 + return m_sign == another.m_sign
1.275 + && m_formatClass == another.m_formatClass
1.276 + && m_exponent == another.m_exponent
1.277 + && m_coefficient == another.m_coefficient;
1.278 +}
1.279 +
1.280 +Decimal::Decimal(int32_t i32)
1.281 + : m_data(i32 < 0 ? Negative : Positive, 0, i32 < 0 ? static_cast<uint64_t>(-static_cast<int64_t>(i32)) : static_cast<uint64_t>(i32))
1.282 +{
1.283 +}
1.284 +
1.285 +Decimal::Decimal(Sign sign, int exponent, uint64_t coefficient)
1.286 + : m_data(sign, coefficient ? exponent : 0, coefficient)
1.287 +{
1.288 +}
1.289 +
1.290 +Decimal::Decimal(const EncodedData& data)
1.291 + : m_data(data)
1.292 +{
1.293 +}
1.294 +
1.295 +Decimal::Decimal(const Decimal& other)
1.296 + : m_data(other.m_data)
1.297 +{
1.298 +}
1.299 +
1.300 +Decimal& Decimal::operator=(const Decimal& other)
1.301 +{
1.302 + m_data = other.m_data;
1.303 + return *this;
1.304 +}
1.305 +
1.306 +Decimal& Decimal::operator+=(const Decimal& other)
1.307 +{
1.308 + m_data = (*this + other).m_data;
1.309 + return *this;
1.310 +}
1.311 +
1.312 +Decimal& Decimal::operator-=(const Decimal& other)
1.313 +{
1.314 + m_data = (*this - other).m_data;
1.315 + return *this;
1.316 +}
1.317 +
1.318 +Decimal& Decimal::operator*=(const Decimal& other)
1.319 +{
1.320 + m_data = (*this * other).m_data;
1.321 + return *this;
1.322 +}
1.323 +
1.324 +Decimal& Decimal::operator/=(const Decimal& other)
1.325 +{
1.326 + m_data = (*this / other).m_data;
1.327 + return *this;
1.328 +}
1.329 +
1.330 +Decimal Decimal::operator-() const
1.331 +{
1.332 + if (isNaN())
1.333 + return *this;
1.334 +
1.335 + Decimal result(*this);
1.336 + result.m_data.setSign(invertSign(m_data.sign()));
1.337 + return result;
1.338 +}
1.339 +
1.340 +Decimal Decimal::operator+(const Decimal& rhs) const
1.341 +{
1.342 + const Decimal& lhs = *this;
1.343 + const Sign lhsSign = lhs.sign();
1.344 + const Sign rhsSign = rhs.sign();
1.345 +
1.346 + SpecialValueHandler handler(lhs, rhs);
1.347 + switch (handler.handle()) {
1.348 + case SpecialValueHandler::BothFinite:
1.349 + break;
1.350 +
1.351 + case SpecialValueHandler::BothInfinity:
1.352 + return lhsSign == rhsSign ? lhs : nan();
1.353 +
1.354 + case SpecialValueHandler::EitherNaN:
1.355 + return handler.value();
1.356 +
1.357 + case SpecialValueHandler::LHSIsInfinity:
1.358 + return lhs;
1.359 +
1.360 + case SpecialValueHandler::RHSIsInfinity:
1.361 + return rhs;
1.362 + }
1.363 +
1.364 + const AlignedOperands alignedOperands = alignOperands(lhs, rhs);
1.365 +
1.366 + const uint64_t result = lhsSign == rhsSign
1.367 + ? alignedOperands.lhsCoefficient + alignedOperands.rhsCoefficient
1.368 + : alignedOperands.lhsCoefficient - alignedOperands.rhsCoefficient;
1.369 +
1.370 + if (lhsSign == Negative && rhsSign == Positive && !result)
1.371 + return Decimal(Positive, alignedOperands.exponent, 0);
1.372 +
1.373 + return static_cast<int64_t>(result) >= 0
1.374 + ? Decimal(lhsSign, alignedOperands.exponent, result)
1.375 + : Decimal(invertSign(lhsSign), alignedOperands.exponent, -static_cast<int64_t>(result));
1.376 +}
1.377 +
1.378 +Decimal Decimal::operator-(const Decimal& rhs) const
1.379 +{
1.380 + const Decimal& lhs = *this;
1.381 + const Sign lhsSign = lhs.sign();
1.382 + const Sign rhsSign = rhs.sign();
1.383 +
1.384 + SpecialValueHandler handler(lhs, rhs);
1.385 + switch (handler.handle()) {
1.386 + case SpecialValueHandler::BothFinite:
1.387 + break;
1.388 +
1.389 + case SpecialValueHandler::BothInfinity:
1.390 + return lhsSign == rhsSign ? nan() : lhs;
1.391 +
1.392 + case SpecialValueHandler::EitherNaN:
1.393 + return handler.value();
1.394 +
1.395 + case SpecialValueHandler::LHSIsInfinity:
1.396 + return lhs;
1.397 +
1.398 + case SpecialValueHandler::RHSIsInfinity:
1.399 + return infinity(invertSign(rhsSign));
1.400 + }
1.401 +
1.402 + const AlignedOperands alignedOperands = alignOperands(lhs, rhs);
1.403 +
1.404 + const uint64_t result = lhsSign == rhsSign
1.405 + ? alignedOperands.lhsCoefficient - alignedOperands.rhsCoefficient
1.406 + : alignedOperands.lhsCoefficient + alignedOperands.rhsCoefficient;
1.407 +
1.408 + if (lhsSign == Negative && rhsSign == Negative && !result)
1.409 + return Decimal(Positive, alignedOperands.exponent, 0);
1.410 +
1.411 + return static_cast<int64_t>(result) >= 0
1.412 + ? Decimal(lhsSign, alignedOperands.exponent, result)
1.413 + : Decimal(invertSign(lhsSign), alignedOperands.exponent, -static_cast<int64_t>(result));
1.414 +}
1.415 +
1.416 +Decimal Decimal::operator*(const Decimal& rhs) const
1.417 +{
1.418 + const Decimal& lhs = *this;
1.419 + const Sign lhsSign = lhs.sign();
1.420 + const Sign rhsSign = rhs.sign();
1.421 + const Sign resultSign = lhsSign == rhsSign ? Positive : Negative;
1.422 +
1.423 + SpecialValueHandler handler(lhs, rhs);
1.424 + switch (handler.handle()) {
1.425 + case SpecialValueHandler::BothFinite: {
1.426 + const uint64_t lhsCoefficient = lhs.m_data.coefficient();
1.427 + const uint64_t rhsCoefficient = rhs.m_data.coefficient();
1.428 + int resultExponent = lhs.exponent() + rhs.exponent();
1.429 + UInt128 work(UInt128::multiply(lhsCoefficient, rhsCoefficient));
1.430 + while (work.high()) {
1.431 + work /= 10;
1.432 + ++resultExponent;
1.433 + }
1.434 + return Decimal(resultSign, resultExponent, work.low());
1.435 + }
1.436 +
1.437 + case SpecialValueHandler::BothInfinity:
1.438 + return infinity(resultSign);
1.439 +
1.440 + case SpecialValueHandler::EitherNaN:
1.441 + return handler.value();
1.442 +
1.443 + case SpecialValueHandler::LHSIsInfinity:
1.444 + return rhs.isZero() ? nan() : infinity(resultSign);
1.445 +
1.446 + case SpecialValueHandler::RHSIsInfinity:
1.447 + return lhs.isZero() ? nan() : infinity(resultSign);
1.448 + }
1.449 +
1.450 + ASSERT_NOT_REACHED();
1.451 + return nan();
1.452 +}
1.453 +
1.454 +Decimal Decimal::operator/(const Decimal& rhs) const
1.455 +{
1.456 + const Decimal& lhs = *this;
1.457 + const Sign lhsSign = lhs.sign();
1.458 + const Sign rhsSign = rhs.sign();
1.459 + const Sign resultSign = lhsSign == rhsSign ? Positive : Negative;
1.460 +
1.461 + SpecialValueHandler handler(lhs, rhs);
1.462 + switch (handler.handle()) {
1.463 + case SpecialValueHandler::BothFinite:
1.464 + break;
1.465 +
1.466 + case SpecialValueHandler::BothInfinity:
1.467 + return nan();
1.468 +
1.469 + case SpecialValueHandler::EitherNaN:
1.470 + return handler.value();
1.471 +
1.472 + case SpecialValueHandler::LHSIsInfinity:
1.473 + return infinity(resultSign);
1.474 +
1.475 + case SpecialValueHandler::RHSIsInfinity:
1.476 + return zero(resultSign);
1.477 + }
1.478 +
1.479 + ASSERT(lhs.isFinite());
1.480 + ASSERT(rhs.isFinite());
1.481 +
1.482 + if (rhs.isZero())
1.483 + return lhs.isZero() ? nan() : infinity(resultSign);
1.484 +
1.485 + int resultExponent = lhs.exponent() - rhs.exponent();
1.486 +
1.487 + if (lhs.isZero())
1.488 + return Decimal(resultSign, resultExponent, 0);
1.489 +
1.490 + uint64_t remainder = lhs.m_data.coefficient();
1.491 + const uint64_t divisor = rhs.m_data.coefficient();
1.492 + uint64_t result = 0;
1.493 + while (result < MaxCoefficient / 100) {
1.494 + while (remainder < divisor) {
1.495 + remainder *= 10;
1.496 + result *= 10;
1.497 + --resultExponent;
1.498 + }
1.499 + result += remainder / divisor;
1.500 + remainder %= divisor;
1.501 + if (!remainder)
1.502 + break;
1.503 + }
1.504 +
1.505 + if (remainder > divisor / 2)
1.506 + ++result;
1.507 +
1.508 + return Decimal(resultSign, resultExponent, result);
1.509 +}
1.510 +
1.511 +bool Decimal::operator==(const Decimal& rhs) const
1.512 +{
1.513 + if (isNaN() || rhs.isNaN())
1.514 + return false;
1.515 + return m_data == rhs.m_data || compareTo(rhs).isZero();
1.516 +}
1.517 +
1.518 +bool Decimal::operator!=(const Decimal& rhs) const
1.519 +{
1.520 + if (isNaN() || rhs.isNaN())
1.521 + return true;
1.522 + if (m_data == rhs.m_data)
1.523 + return false;
1.524 + const Decimal result = compareTo(rhs);
1.525 + if (result.isNaN())
1.526 + return false;
1.527 + return !result.isZero();
1.528 +}
1.529 +
1.530 +bool Decimal::operator<(const Decimal& rhs) const
1.531 +{
1.532 + const Decimal result = compareTo(rhs);
1.533 + if (result.isNaN())
1.534 + return false;
1.535 + return !result.isZero() && result.isNegative();
1.536 +}
1.537 +
1.538 +bool Decimal::operator<=(const Decimal& rhs) const
1.539 +{
1.540 + if (isNaN() || rhs.isNaN())
1.541 + return false;
1.542 + if (m_data == rhs.m_data)
1.543 + return true;
1.544 + const Decimal result = compareTo(rhs);
1.545 + if (result.isNaN())
1.546 + return false;
1.547 + return result.isZero() || result.isNegative();
1.548 +}
1.549 +
1.550 +bool Decimal::operator>(const Decimal& rhs) const
1.551 +{
1.552 + const Decimal result = compareTo(rhs);
1.553 + if (result.isNaN())
1.554 + return false;
1.555 + return !result.isZero() && result.isPositive();
1.556 +}
1.557 +
1.558 +bool Decimal::operator>=(const Decimal& rhs) const
1.559 +{
1.560 + if (isNaN() || rhs.isNaN())
1.561 + return false;
1.562 + if (m_data == rhs.m_data)
1.563 + return true;
1.564 + const Decimal result = compareTo(rhs);
1.565 + if (result.isNaN())
1.566 + return false;
1.567 + return result.isZero() || !result.isNegative();
1.568 +}
1.569 +
1.570 +Decimal Decimal::abs() const
1.571 +{
1.572 + Decimal result(*this);
1.573 + result.m_data.setSign(Positive);
1.574 + return result;
1.575 +}
1.576 +
1.577 +Decimal::AlignedOperands Decimal::alignOperands(const Decimal& lhs, const Decimal& rhs)
1.578 +{
1.579 + ASSERT(lhs.isFinite());
1.580 + ASSERT(rhs.isFinite());
1.581 +
1.582 + const int lhsExponent = lhs.exponent();
1.583 + const int rhsExponent = rhs.exponent();
1.584 + int exponent = std::min(lhsExponent, rhsExponent);
1.585 + uint64_t lhsCoefficient = lhs.m_data.coefficient();
1.586 + uint64_t rhsCoefficient = rhs.m_data.coefficient();
1.587 +
1.588 + if (lhsExponent > rhsExponent) {
1.589 + const int numberOfLHSDigits = countDigits(lhsCoefficient);
1.590 + if (numberOfLHSDigits) {
1.591 + const int lhsShiftAmount = lhsExponent - rhsExponent;
1.592 + const int overflow = numberOfLHSDigits + lhsShiftAmount - Precision;
1.593 + if (overflow <= 0)
1.594 + lhsCoefficient = scaleUp(lhsCoefficient, lhsShiftAmount);
1.595 + else {
1.596 + lhsCoefficient = scaleUp(lhsCoefficient, lhsShiftAmount - overflow);
1.597 + rhsCoefficient = scaleDown(rhsCoefficient, overflow);
1.598 + exponent += overflow;
1.599 + }
1.600 + }
1.601 +
1.602 + } else if (lhsExponent < rhsExponent) {
1.603 + const int numberOfRHSDigits = countDigits(rhsCoefficient);
1.604 + if (numberOfRHSDigits) {
1.605 + const int rhsShiftAmount = rhsExponent - lhsExponent;
1.606 + const int overflow = numberOfRHSDigits + rhsShiftAmount - Precision;
1.607 + if (overflow <= 0)
1.608 + rhsCoefficient = scaleUp(rhsCoefficient, rhsShiftAmount);
1.609 + else {
1.610 + rhsCoefficient = scaleUp(rhsCoefficient, rhsShiftAmount - overflow);
1.611 + lhsCoefficient = scaleDown(lhsCoefficient, overflow);
1.612 + exponent += overflow;
1.613 + }
1.614 + }
1.615 + }
1.616 +
1.617 + AlignedOperands alignedOperands;
1.618 + alignedOperands.exponent = exponent;
1.619 + alignedOperands.lhsCoefficient = lhsCoefficient;
1.620 + alignedOperands.rhsCoefficient = rhsCoefficient;
1.621 + return alignedOperands;
1.622 +}
1.623 +
1.624 +// Round toward positive infinity.
1.625 +// Note: Mac ports defines ceil(x) as wtf_ceil(x), so we can't use name "ceil" here.
1.626 +Decimal Decimal::ceiling() const
1.627 +{
1.628 + if (isSpecial())
1.629 + return *this;
1.630 +
1.631 + if (exponent() >= 0)
1.632 + return *this;
1.633 +
1.634 + uint64_t coefficient = m_data.coefficient();
1.635 + const int numberOfDigits = countDigits(coefficient);
1.636 + const int numberOfDropDigits = -exponent();
1.637 + if (numberOfDigits < numberOfDropDigits)
1.638 + return isPositive() ? Decimal(1) : zero(Positive);
1.639 +
1.640 + uint64_t result = scaleDown(coefficient, numberOfDropDigits);
1.641 + uint64_t droppedDigits = coefficient - scaleUp(result, numberOfDropDigits);
1.642 + if (droppedDigits && isPositive())
1.643 + result += 1;
1.644 + return Decimal(sign(), 0, result);
1.645 +}
1.646 +
1.647 +Decimal Decimal::compareTo(const Decimal& rhs) const
1.648 +{
1.649 + const Decimal result(*this - rhs);
1.650 + switch (result.m_data.formatClass()) {
1.651 + case EncodedData::ClassInfinity:
1.652 + return result.isNegative() ? Decimal(-1) : Decimal(1);
1.653 +
1.654 + case EncodedData::ClassNaN:
1.655 + case EncodedData::ClassNormal:
1.656 + return result;
1.657 +
1.658 + case EncodedData::ClassZero:
1.659 + return zero(Positive);
1.660 +
1.661 + default:
1.662 + ASSERT_NOT_REACHED();
1.663 + return nan();
1.664 + }
1.665 +}
1.666 +
1.667 +// Round toward negative infinity.
1.668 +Decimal Decimal::floor() const
1.669 +{
1.670 + if (isSpecial())
1.671 + return *this;
1.672 +
1.673 + if (exponent() >= 0)
1.674 + return *this;
1.675 +
1.676 + uint64_t coefficient = m_data.coefficient();
1.677 + const int numberOfDigits = countDigits(coefficient);
1.678 + const int numberOfDropDigits = -exponent();
1.679 + if (numberOfDigits < numberOfDropDigits)
1.680 + return isPositive() ? zero(Positive) : Decimal(-1);
1.681 +
1.682 + uint64_t result = scaleDown(coefficient, numberOfDropDigits);
1.683 + uint64_t droppedDigits = coefficient - scaleUp(result, numberOfDropDigits);
1.684 + if (droppedDigits && isNegative()) {
1.685 + result += 1;
1.686 + }
1.687 + return Decimal(sign(), 0, result);
1.688 +}
1.689 +
1.690 +Decimal Decimal::fromDouble(double doubleValue)
1.691 +{
1.692 + if (std::isfinite(doubleValue))
1.693 + return fromString(mozToString(doubleValue));
1.694 +
1.695 + if (std::isinf(doubleValue))
1.696 + return infinity(doubleValue < 0 ? Negative : Positive);
1.697 +
1.698 + return nan();
1.699 +}
1.700 +
1.701 +Decimal Decimal::fromString(const String& str)
1.702 +{
1.703 + int exponent = 0;
1.704 + Sign exponentSign = Positive;
1.705 + int numberOfDigits = 0;
1.706 + int numberOfDigitsAfterDot = 0;
1.707 + int numberOfExtraDigits = 0;
1.708 + Sign sign = Positive;
1.709 +
1.710 + enum {
1.711 + StateDigit,
1.712 + StateDot,
1.713 + StateDotDigit,
1.714 + StateE,
1.715 + StateEDigit,
1.716 + StateESign,
1.717 + StateSign,
1.718 + StateStart,
1.719 + StateZero,
1.720 + } state = StateStart;
1.721 +
1.722 +#define HandleCharAndBreak(expected, nextState) \
1.723 + if (ch == expected) { \
1.724 + state = nextState; \
1.725 + break; \
1.726 + }
1.727 +
1.728 +#define HandleTwoCharsAndBreak(expected1, expected2, nextState) \
1.729 + if (ch == expected1 || ch == expected2) { \
1.730 + state = nextState; \
1.731 + break; \
1.732 + }
1.733 +
1.734 + uint64_t accumulator = 0;
1.735 + for (unsigned index = 0; index < str.length(); ++index) {
1.736 + const int ch = str[index];
1.737 + switch (state) {
1.738 + case StateDigit:
1.739 + if (ch >= '0' && ch <= '9') {
1.740 + if (numberOfDigits < Precision) {
1.741 + ++numberOfDigits;
1.742 + accumulator *= 10;
1.743 + accumulator += ch - '0';
1.744 + } else
1.745 + ++numberOfExtraDigits;
1.746 + break;
1.747 + }
1.748 +
1.749 + HandleCharAndBreak('.', StateDot);
1.750 + HandleTwoCharsAndBreak('E', 'e', StateE);
1.751 + return nan();
1.752 +
1.753 + case StateDot:
1.754 + if (ch >= '0' && ch <= '9') {
1.755 + if (numberOfDigits < Precision) {
1.756 + ++numberOfDigits;
1.757 + ++numberOfDigitsAfterDot;
1.758 + accumulator *= 10;
1.759 + accumulator += ch - '0';
1.760 + }
1.761 + state = StateDotDigit;
1.762 + break;
1.763 + }
1.764 +
1.765 + case StateDotDigit:
1.766 + if (ch >= '0' && ch <= '9') {
1.767 + if (numberOfDigits < Precision) {
1.768 + ++numberOfDigits;
1.769 + ++numberOfDigitsAfterDot;
1.770 + accumulator *= 10;
1.771 + accumulator += ch - '0';
1.772 + }
1.773 + break;
1.774 + }
1.775 +
1.776 + HandleTwoCharsAndBreak('E', 'e', StateE);
1.777 + return nan();
1.778 +
1.779 + case StateE:
1.780 + if (ch == '+') {
1.781 + exponentSign = Positive;
1.782 + state = StateESign;
1.783 + break;
1.784 + }
1.785 +
1.786 + if (ch == '-') {
1.787 + exponentSign = Negative;
1.788 + state = StateESign;
1.789 + break;
1.790 + }
1.791 +
1.792 + if (ch >= '0' && ch <= '9') {
1.793 + exponent = ch - '0';
1.794 + state = StateEDigit;
1.795 + break;
1.796 + }
1.797 +
1.798 + return nan();
1.799 +
1.800 + case StateEDigit:
1.801 + if (ch >= '0' && ch <= '9') {
1.802 + exponent *= 10;
1.803 + exponent += ch - '0';
1.804 + if (exponent > ExponentMax + Precision) {
1.805 + if (accumulator)
1.806 + return exponentSign == Negative ? zero(Positive) : infinity(sign);
1.807 + return zero(sign);
1.808 + }
1.809 + state = StateEDigit;
1.810 + break;
1.811 + }
1.812 +
1.813 + return nan();
1.814 +
1.815 + case StateESign:
1.816 + if (ch >= '0' && ch <= '9') {
1.817 + exponent = ch - '0';
1.818 + state = StateEDigit;
1.819 + break;
1.820 + }
1.821 +
1.822 + return nan();
1.823 +
1.824 + case StateSign:
1.825 + if (ch >= '1' && ch <= '9') {
1.826 + accumulator = ch - '0';
1.827 + numberOfDigits = 1;
1.828 + state = StateDigit;
1.829 + break;
1.830 + }
1.831 +
1.832 + HandleCharAndBreak('0', StateZero);
1.833 + return nan();
1.834 +
1.835 + case StateStart:
1.836 + if (ch >= '1' && ch <= '9') {
1.837 + accumulator = ch - '0';
1.838 + numberOfDigits = 1;
1.839 + state = StateDigit;
1.840 + break;
1.841 + }
1.842 +
1.843 + if (ch == '-') {
1.844 + sign = Negative;
1.845 + state = StateSign;
1.846 + break;
1.847 + }
1.848 +
1.849 + if (ch == '+') {
1.850 + sign = Positive;
1.851 + state = StateSign;
1.852 + break;
1.853 + }
1.854 +
1.855 + HandleCharAndBreak('0', StateZero);
1.856 + HandleCharAndBreak('.', StateDot);
1.857 + return nan();
1.858 +
1.859 + case StateZero:
1.860 + if (ch == '0')
1.861 + break;
1.862 +
1.863 + if (ch >= '1' && ch <= '9') {
1.864 + accumulator = ch - '0';
1.865 + numberOfDigits = 1;
1.866 + state = StateDigit;
1.867 + break;
1.868 + }
1.869 +
1.870 + HandleCharAndBreak('.', StateDot);
1.871 + HandleTwoCharsAndBreak('E', 'e', StateE);
1.872 + return nan();
1.873 +
1.874 + default:
1.875 + ASSERT_NOT_REACHED();
1.876 + return nan();
1.877 + }
1.878 + }
1.879 +
1.880 + if (state == StateZero)
1.881 + return zero(sign);
1.882 +
1.883 + if (state == StateDigit || state == StateEDigit || state == StateDotDigit) {
1.884 + int resultExponent = exponent * (exponentSign == Negative ? -1 : 1) - numberOfDigitsAfterDot + numberOfExtraDigits;
1.885 + if (resultExponent < ExponentMin)
1.886 + return zero(Positive);
1.887 +
1.888 + const int overflow = resultExponent - ExponentMax + 1;
1.889 + if (overflow > 0) {
1.890 + if (overflow + numberOfDigits - numberOfDigitsAfterDot > Precision)
1.891 + return infinity(sign);
1.892 + accumulator = scaleUp(accumulator, overflow);
1.893 + resultExponent -= overflow;
1.894 + }
1.895 +
1.896 + return Decimal(sign, resultExponent, accumulator);
1.897 + }
1.898 +
1.899 + return nan();
1.900 +}
1.901 +
1.902 +Decimal Decimal::infinity(const Sign sign)
1.903 +{
1.904 + return Decimal(EncodedData(sign, EncodedData::ClassInfinity));
1.905 +}
1.906 +
1.907 +Decimal Decimal::nan()
1.908 +{
1.909 + return Decimal(EncodedData(Positive, EncodedData::ClassNaN));
1.910 +}
1.911 +
1.912 +Decimal Decimal::remainder(const Decimal& rhs) const
1.913 +{
1.914 + const Decimal quotient = *this / rhs;
1.915 + return quotient.isSpecial() ? quotient : *this - (quotient.isNegative() ? quotient.ceiling() : quotient.floor()) * rhs;
1.916 +}
1.917 +
1.918 +Decimal Decimal::round() const
1.919 +{
1.920 + if (isSpecial())
1.921 + return *this;
1.922 +
1.923 + if (exponent() >= 0)
1.924 + return *this;
1.925 +
1.926 + uint64_t result = m_data.coefficient();
1.927 + const int numberOfDigits = countDigits(result);
1.928 + const int numberOfDropDigits = -exponent();
1.929 + if (numberOfDigits < numberOfDropDigits)
1.930 + return zero(Positive);
1.931 +
1.932 + // We're implementing round-half-away-from-zero, so we only need the one
1.933 + // (the most significant) fractional digit:
1.934 + result = scaleDown(result, numberOfDropDigits - 1);
1.935 + if (result % 10 >= 5)
1.936 + result += 10;
1.937 + result /= 10;
1.938 + return Decimal(sign(), 0, result);
1.939 +}
1.940 +
1.941 +double Decimal::toDouble() const
1.942 +{
1.943 + if (isFinite()) {
1.944 + bool valid;
1.945 + const double doubleValue = mozToDouble(toString(), &valid);
1.946 + return valid ? doubleValue : std::numeric_limits<double>::quiet_NaN();
1.947 + }
1.948 +
1.949 + if (isInfinity())
1.950 + return isNegative() ? -std::numeric_limits<double>::infinity() : std::numeric_limits<double>::infinity();
1.951 +
1.952 + return std::numeric_limits<double>::quiet_NaN();
1.953 +}
1.954 +
1.955 +String Decimal::toString() const
1.956 +{
1.957 + switch (m_data.formatClass()) {
1.958 + case EncodedData::ClassInfinity:
1.959 + return sign() ? "-Infinity" : "Infinity";
1.960 +
1.961 + case EncodedData::ClassNaN:
1.962 + return "NaN";
1.963 +
1.964 + case EncodedData::ClassNormal:
1.965 + case EncodedData::ClassZero:
1.966 + break;
1.967 +
1.968 + default:
1.969 + ASSERT_NOT_REACHED();
1.970 + return "";
1.971 + }
1.972 +
1.973 + StringBuilder builder;
1.974 + if (sign())
1.975 + builder.append('-');
1.976 +
1.977 + int originalExponent = exponent();
1.978 + uint64_t coefficient = m_data.coefficient();
1.979 +
1.980 + if (originalExponent < 0) {
1.981 + const int maxDigits = DBL_DIG;
1.982 + uint64_t lastDigit = 0;
1.983 + while (countDigits(coefficient) > maxDigits) {
1.984 + lastDigit = coefficient % 10;
1.985 + coefficient /= 10;
1.986 + ++originalExponent;
1.987 + }
1.988 +
1.989 + if (lastDigit >= 5)
1.990 + ++coefficient;
1.991 +
1.992 + while (originalExponent < 0 && coefficient && !(coefficient % 10)) {
1.993 + coefficient /= 10;
1.994 + ++originalExponent;
1.995 + }
1.996 + }
1.997 +
1.998 + const String digits = mozToString(coefficient);
1.999 + int coefficientLength = static_cast<int>(digits.length());
1.1000 + const int adjustedExponent = originalExponent + coefficientLength - 1;
1.1001 + if (originalExponent <= 0 && adjustedExponent >= -6) {
1.1002 + if (!originalExponent) {
1.1003 + builder.append(digits);
1.1004 + return builder.toString();
1.1005 + }
1.1006 +
1.1007 + if (adjustedExponent >= 0) {
1.1008 + for (int i = 0; i < coefficientLength; ++i) {
1.1009 + builder.append(digits[i]);
1.1010 + if (i == adjustedExponent)
1.1011 + builder.append('.');
1.1012 + }
1.1013 + return builder.toString();
1.1014 + }
1.1015 +
1.1016 + builder.appendLiteral("0.");
1.1017 + for (int i = adjustedExponent + 1; i < 0; ++i)
1.1018 + builder.append('0');
1.1019 +
1.1020 + builder.append(digits);
1.1021 +
1.1022 + } else {
1.1023 + builder.append(digits[0]);
1.1024 + while (coefficientLength >= 2 && digits[coefficientLength - 1] == '0')
1.1025 + --coefficientLength;
1.1026 + if (coefficientLength >= 2) {
1.1027 + builder.append('.');
1.1028 + for (int i = 1; i < coefficientLength; ++i)
1.1029 + builder.append(digits[i]);
1.1030 + }
1.1031 +
1.1032 + if (adjustedExponent) {
1.1033 + builder.append(adjustedExponent < 0 ? "e" : "e+");
1.1034 + builder.appendNumber(adjustedExponent);
1.1035 + }
1.1036 + }
1.1037 + return builder.toString();
1.1038 +}
1.1039 +
1.1040 +bool Decimal::toString(char* strBuf, size_t bufLength) const
1.1041 +{
1.1042 + ASSERT(bufLength > 0);
1.1043 + String str = toString();
1.1044 + size_t length = str.copy(strBuf, bufLength);
1.1045 + if (length < bufLength) {
1.1046 + strBuf[length] = '\0';
1.1047 + return true;
1.1048 + }
1.1049 + strBuf[bufLength - 1] = '\0';
1.1050 + return false;
1.1051 +}
1.1052 +
1.1053 +Decimal Decimal::zero(Sign sign)
1.1054 +{
1.1055 + return Decimal(EncodedData(sign, EncodedData::ClassZero));
1.1056 +}
1.1057 +
1.1058 +} // namespace WebCore
1.1059 +
