| Index: third_party/WebKit/Source/wtf/dtoa/double.h
|
| diff --git a/third_party/WebKit/Source/wtf/dtoa/double.h b/third_party/WebKit/Source/wtf/dtoa/double.h
|
| index d0f449d20f0669586ef7c5ea48918b9223cde83c..9aa2df72f39df0dc220093c18f68cb991a9ff90f 100644
|
| --- a/third_party/WebKit/Source/wtf/dtoa/double.h
|
| +++ b/third_party/WebKit/Source/wtf/dtoa/double.h
|
| @@ -34,216 +34,216 @@ namespace WTF {
|
|
|
| namespace double_conversion {
|
|
|
| - // We assume that doubles and uint64_t have the same endianness.
|
| - static uint64_t double_to_uint64(double d) { return BitCast<uint64_t>(d); }
|
| - static double uint64_to_double(uint64_t d64) { return BitCast<double>(d64); }
|
| -
|
| - // Helper functions for doubles.
|
| - class Double {
|
| - public:
|
| - static const uint64_t kSignMask = UINT64_2PART_C(0x80000000, 00000000);
|
| - static const uint64_t kExponentMask = UINT64_2PART_C(0x7FF00000, 00000000);
|
| - static const uint64_t kSignificandMask = UINT64_2PART_C(0x000FFFFF, FFFFFFFF);
|
| - static const uint64_t kHiddenBit = UINT64_2PART_C(0x00100000, 00000000);
|
| - static const int kPhysicalSignificandSize = 52; // Excludes the hidden bit.
|
| - static const int kSignificandSize = 53;
|
| -
|
| - Double() : d64_(0) {}
|
| - explicit Double(double d) : d64_(double_to_uint64(d)) {}
|
| - explicit Double(uint64_t d64) : d64_(d64) {}
|
| - explicit Double(DiyFp diy_fp)
|
| - : d64_(DiyFpToUint64(diy_fp)) {}
|
| -
|
| - // The value encoded by this Double must be greater or equal to +0.0.
|
| - // It must not be special (infinity, or NaN).
|
| - DiyFp AsDiyFp() const {
|
| - ASSERT(Sign() > 0);
|
| - ASSERT(!IsSpecial());
|
| - return DiyFp(Significand(), Exponent());
|
| - }
|
| -
|
| - // The value encoded by this Double must be strictly greater than 0.
|
| - DiyFp AsNormalizedDiyFp() const {
|
| - ASSERT(value() > 0.0);
|
| - uint64_t f = Significand();
|
| - int e = Exponent();
|
| -
|
| - // The current double could be a denormal.
|
| - while ((f & kHiddenBit) == 0) {
|
| - f <<= 1;
|
| - e--;
|
| - }
|
| - // Do the final shifts in one go.
|
| - f <<= DiyFp::kSignificandSize - kSignificandSize;
|
| - e -= DiyFp::kSignificandSize - kSignificandSize;
|
| - return DiyFp(f, e);
|
| - }
|
| -
|
| - // Returns the double's bit as uint64.
|
| - uint64_t AsUint64() const {
|
| - return d64_;
|
| - }
|
| -
|
| - // Returns the next greater double. Returns +infinity on input +infinity.
|
| - double NextDouble() const {
|
| - if (d64_ == kInfinity) return Double(kInfinity).value();
|
| - if (Sign() < 0 && Significand() == 0) {
|
| - // -0.0
|
| - return 0.0;
|
| - }
|
| - if (Sign() < 0) {
|
| - return Double(d64_ - 1).value();
|
| - } else {
|
| - return Double(d64_ + 1).value();
|
| - }
|
| - }
|
| -
|
| - int Exponent() const {
|
| - if (IsDenormal()) return kDenormalExponent;
|
| -
|
| - uint64_t d64 = AsUint64();
|
| - int biased_e =
|
| - static_cast<int>((d64 & kExponentMask) >> kPhysicalSignificandSize);
|
| - return biased_e - kExponentBias;
|
| - }
|
| -
|
| - uint64_t Significand() const {
|
| - uint64_t d64 = AsUint64();
|
| - uint64_t significand = d64 & kSignificandMask;
|
| - if (!IsDenormal()) {
|
| - return significand + kHiddenBit;
|
| - } else {
|
| - return significand;
|
| - }
|
| - }
|
| -
|
| - // Returns true if the double is a denormal.
|
| - bool IsDenormal() const {
|
| - uint64_t d64 = AsUint64();
|
| - return (d64 & kExponentMask) == 0;
|
| - }
|
| -
|
| - // We consider denormals not to be special.
|
| - // Hence only Infinity and NaN are special.
|
| - bool IsSpecial() const {
|
| - uint64_t d64 = AsUint64();
|
| - return (d64 & kExponentMask) == kExponentMask;
|
| - }
|
| -
|
| - bool IsNan() const {
|
| - uint64_t d64 = AsUint64();
|
| - return ((d64 & kExponentMask) == kExponentMask) &&
|
| - ((d64 & kSignificandMask) != 0);
|
| - }
|
| -
|
| - bool IsInfinite() const {
|
| - uint64_t d64 = AsUint64();
|
| - return ((d64 & kExponentMask) == kExponentMask) &&
|
| - ((d64 & kSignificandMask) == 0);
|
| - }
|
| -
|
| - int Sign() const {
|
| - uint64_t d64 = AsUint64();
|
| - return (d64 & kSignMask) == 0? 1: -1;
|
| - }
|
| -
|
| - // Precondition: the value encoded by this Double must be greater or equal
|
| - // than +0.0.
|
| - DiyFp UpperBoundary() const {
|
| - ASSERT(Sign() > 0);
|
| - return DiyFp(Significand() * 2 + 1, Exponent() - 1);
|
| - }
|
| -
|
| - // Computes the two boundaries of this.
|
| - // The bigger boundary (m_plus) is normalized. The lower boundary has the same
|
| - // exponent as m_plus.
|
| - // Precondition: the value encoded by this Double must be greater than 0.
|
| - void NormalizedBoundaries(DiyFp* out_m_minus, DiyFp* out_m_plus) const {
|
| - ASSERT(value() > 0.0);
|
| - DiyFp v = this->AsDiyFp();
|
| - bool significand_is_zero = (v.f() == kHiddenBit);
|
| - DiyFp m_plus = DiyFp::Normalize(DiyFp((v.f() << 1) + 1, v.e() - 1));
|
| - DiyFp m_minus;
|
| - if (significand_is_zero && v.e() != kDenormalExponent) {
|
| - // The boundary is closer. Think of v = 1000e10 and v- = 9999e9.
|
| - // Then the boundary (== (v - v-)/2) is not just at a distance of 1e9 but
|
| - // at a distance of 1e8.
|
| - // The only exception is for the smallest normal: the largest denormal is
|
| - // at the same distance as its successor.
|
| - // Note: denormals have the same exponent as the smallest normals.
|
| - m_minus = DiyFp((v.f() << 2) - 1, v.e() - 2);
|
| - } else {
|
| - m_minus = DiyFp((v.f() << 1) - 1, v.e() - 1);
|
| - }
|
| - m_minus.set_f(m_minus.f() << (m_minus.e() - m_plus.e()));
|
| - m_minus.set_e(m_plus.e());
|
| - *out_m_plus = m_plus;
|
| - *out_m_minus = m_minus;
|
| - }
|
| -
|
| - double value() const { return uint64_to_double(d64_); }
|
| -
|
| - // Returns the significand size for a given order of magnitude.
|
| - // If v = f*2^e with 2^p-1 <= f <= 2^p then p+e is v's order of magnitude.
|
| - // This function returns the number of significant binary digits v will have
|
| - // once it's encoded into a double. In almost all cases this is equal to
|
| - // kSignificandSize. The only exceptions are denormals. They start with
|
| - // leading zeroes and their effective significand-size is hence smaller.
|
| - static int SignificandSizeForOrderOfMagnitude(int order) {
|
| - if (order >= (kDenormalExponent + kSignificandSize)) {
|
| - return kSignificandSize;
|
| - }
|
| - if (order <= kDenormalExponent) return 0;
|
| - return order - kDenormalExponent;
|
| - }
|
| -
|
| - static double Infinity() {
|
| - return Double(kInfinity).value();
|
| - }
|
| -
|
| - static double NaN() {
|
| - return Double(kNaN).value();
|
| - }
|
| -
|
| - private:
|
| - static const int kExponentBias = 0x3FF + kPhysicalSignificandSize;
|
| - static const int kDenormalExponent = -kExponentBias + 1;
|
| - static const int kMaxExponent = 0x7FF - kExponentBias;
|
| - static const uint64_t kInfinity = UINT64_2PART_C(0x7FF00000, 00000000);
|
| - static const uint64_t kNaN = UINT64_2PART_C(0x7FF80000, 00000000);
|
| -
|
| - const uint64_t d64_;
|
| -
|
| - static uint64_t DiyFpToUint64(DiyFp diy_fp) {
|
| - uint64_t significand = diy_fp.f();
|
| - int exponent = diy_fp.e();
|
| - while (significand > kHiddenBit + kSignificandMask) {
|
| - significand >>= 1;
|
| - exponent++;
|
| - }
|
| - if (exponent >= kMaxExponent) {
|
| - return kInfinity;
|
| - }
|
| - if (exponent < kDenormalExponent) {
|
| - return 0;
|
| - }
|
| - while (exponent > kDenormalExponent && (significand & kHiddenBit) == 0) {
|
| - significand <<= 1;
|
| - exponent--;
|
| - }
|
| - uint64_t biased_exponent;
|
| - if (exponent == kDenormalExponent && (significand & kHiddenBit) == 0) {
|
| - biased_exponent = 0;
|
| - } else {
|
| - biased_exponent = static_cast<uint64_t>(exponent + kExponentBias);
|
| - }
|
| - return (significand & kSignificandMask) |
|
| - (biased_exponent << kPhysicalSignificandSize);
|
| - }
|
| - };
|
| +// We assume that doubles and uint64_t have the same endianness.
|
| +static uint64_t double_to_uint64(double d) {
|
| + return BitCast<uint64_t>(d);
|
| +}
|
| +static double uint64_to_double(uint64_t d64) {
|
| + return BitCast<double>(d64);
|
| +}
|
| +
|
| +// Helper functions for doubles.
|
| +class Double {
|
| + public:
|
| + static const uint64_t kSignMask = UINT64_2PART_C(0x80000000, 00000000);
|
| + static const uint64_t kExponentMask = UINT64_2PART_C(0x7FF00000, 00000000);
|
| + static const uint64_t kSignificandMask = UINT64_2PART_C(0x000FFFFF, FFFFFFFF);
|
| + static const uint64_t kHiddenBit = UINT64_2PART_C(0x00100000, 00000000);
|
| + static const int kPhysicalSignificandSize = 52; // Excludes the hidden bit.
|
| + static const int kSignificandSize = 53;
|
| +
|
| + Double() : d64_(0) {}
|
| + explicit Double(double d) : d64_(double_to_uint64(d)) {}
|
| + explicit Double(uint64_t d64) : d64_(d64) {}
|
| + explicit Double(DiyFp diy_fp) : d64_(DiyFpToUint64(diy_fp)) {}
|
| +
|
| + // The value encoded by this Double must be greater or equal to +0.0.
|
| + // It must not be special (infinity, or NaN).
|
| + DiyFp AsDiyFp() const {
|
| + ASSERT(Sign() > 0);
|
| + ASSERT(!IsSpecial());
|
| + return DiyFp(Significand(), Exponent());
|
| + }
|
| +
|
| + // The value encoded by this Double must be strictly greater than 0.
|
| + DiyFp AsNormalizedDiyFp() const {
|
| + ASSERT(value() > 0.0);
|
| + uint64_t f = Significand();
|
| + int e = Exponent();
|
| +
|
| + // The current double could be a denormal.
|
| + while ((f & kHiddenBit) == 0) {
|
| + f <<= 1;
|
| + e--;
|
| + }
|
| + // Do the final shifts in one go.
|
| + f <<= DiyFp::kSignificandSize - kSignificandSize;
|
| + e -= DiyFp::kSignificandSize - kSignificandSize;
|
| + return DiyFp(f, e);
|
| + }
|
| +
|
| + // Returns the double's bit as uint64.
|
| + uint64_t AsUint64() const { return d64_; }
|
| +
|
| + // Returns the next greater double. Returns +infinity on input +infinity.
|
| + double NextDouble() const {
|
| + if (d64_ == kInfinity)
|
| + return Double(kInfinity).value();
|
| + if (Sign() < 0 && Significand() == 0) {
|
| + // -0.0
|
| + return 0.0;
|
| + }
|
| + if (Sign() < 0) {
|
| + return Double(d64_ - 1).value();
|
| + } else {
|
| + return Double(d64_ + 1).value();
|
| + }
|
| + }
|
| +
|
| + int Exponent() const {
|
| + if (IsDenormal())
|
| + return kDenormalExponent;
|
| +
|
| + uint64_t d64 = AsUint64();
|
| + int biased_e =
|
| + static_cast<int>((d64 & kExponentMask) >> kPhysicalSignificandSize);
|
| + return biased_e - kExponentBias;
|
| + }
|
| +
|
| + uint64_t Significand() const {
|
| + uint64_t d64 = AsUint64();
|
| + uint64_t significand = d64 & kSignificandMask;
|
| + if (!IsDenormal()) {
|
| + return significand + kHiddenBit;
|
| + } else {
|
| + return significand;
|
| + }
|
| + }
|
| +
|
| + // Returns true if the double is a denormal.
|
| + bool IsDenormal() const {
|
| + uint64_t d64 = AsUint64();
|
| + return (d64 & kExponentMask) == 0;
|
| + }
|
| +
|
| + // We consider denormals not to be special.
|
| + // Hence only Infinity and NaN are special.
|
| + bool IsSpecial() const {
|
| + uint64_t d64 = AsUint64();
|
| + return (d64 & kExponentMask) == kExponentMask;
|
| + }
|
| +
|
| + bool IsNan() const {
|
| + uint64_t d64 = AsUint64();
|
| + return ((d64 & kExponentMask) == kExponentMask) &&
|
| + ((d64 & kSignificandMask) != 0);
|
| + }
|
| +
|
| + bool IsInfinite() const {
|
| + uint64_t d64 = AsUint64();
|
| + return ((d64 & kExponentMask) == kExponentMask) &&
|
| + ((d64 & kSignificandMask) == 0);
|
| + }
|
| +
|
| + int Sign() const {
|
| + uint64_t d64 = AsUint64();
|
| + return (d64 & kSignMask) == 0 ? 1 : -1;
|
| + }
|
| +
|
| + // Precondition: the value encoded by this Double must be greater or equal
|
| + // than +0.0.
|
| + DiyFp UpperBoundary() const {
|
| + ASSERT(Sign() > 0);
|
| + return DiyFp(Significand() * 2 + 1, Exponent() - 1);
|
| + }
|
| +
|
| + // Computes the two boundaries of this.
|
| + // The bigger boundary (m_plus) is normalized. The lower boundary has the same
|
| + // exponent as m_plus.
|
| + // Precondition: the value encoded by this Double must be greater than 0.
|
| + void NormalizedBoundaries(DiyFp* out_m_minus, DiyFp* out_m_plus) const {
|
| + ASSERT(value() > 0.0);
|
| + DiyFp v = this->AsDiyFp();
|
| + bool significand_is_zero = (v.f() == kHiddenBit);
|
| + DiyFp m_plus = DiyFp::Normalize(DiyFp((v.f() << 1) + 1, v.e() - 1));
|
| + DiyFp m_minus;
|
| + if (significand_is_zero && v.e() != kDenormalExponent) {
|
| + // The boundary is closer. Think of v = 1000e10 and v- = 9999e9.
|
| + // Then the boundary (== (v - v-)/2) is not just at a distance of 1e9 but
|
| + // at a distance of 1e8.
|
| + // The only exception is for the smallest normal: the largest denormal is
|
| + // at the same distance as its successor.
|
| + // Note: denormals have the same exponent as the smallest normals.
|
| + m_minus = DiyFp((v.f() << 2) - 1, v.e() - 2);
|
| + } else {
|
| + m_minus = DiyFp((v.f() << 1) - 1, v.e() - 1);
|
| + }
|
| + m_minus.set_f(m_minus.f() << (m_minus.e() - m_plus.e()));
|
| + m_minus.set_e(m_plus.e());
|
| + *out_m_plus = m_plus;
|
| + *out_m_minus = m_minus;
|
| + }
|
| +
|
| + double value() const { return uint64_to_double(d64_); }
|
| +
|
| + // Returns the significand size for a given order of magnitude.
|
| + // If v = f*2^e with 2^p-1 <= f <= 2^p then p+e is v's order of magnitude.
|
| + // This function returns the number of significant binary digits v will have
|
| + // once it's encoded into a double. In almost all cases this is equal to
|
| + // kSignificandSize. The only exceptions are denormals. They start with
|
| + // leading zeroes and their effective significand-size is hence smaller.
|
| + static int SignificandSizeForOrderOfMagnitude(int order) {
|
| + if (order >= (kDenormalExponent + kSignificandSize)) {
|
| + return kSignificandSize;
|
| + }
|
| + if (order <= kDenormalExponent)
|
| + return 0;
|
| + return order - kDenormalExponent;
|
| + }
|
| +
|
| + static double Infinity() { return Double(kInfinity).value(); }
|
| +
|
| + static double NaN() { return Double(kNaN).value(); }
|
| +
|
| + private:
|
| + static const int kExponentBias = 0x3FF + kPhysicalSignificandSize;
|
| + static const int kDenormalExponent = -kExponentBias + 1;
|
| + static const int kMaxExponent = 0x7FF - kExponentBias;
|
| + static const uint64_t kInfinity = UINT64_2PART_C(0x7FF00000, 00000000);
|
| + static const uint64_t kNaN = UINT64_2PART_C(0x7FF80000, 00000000);
|
| +
|
| + const uint64_t d64_;
|
| +
|
| + static uint64_t DiyFpToUint64(DiyFp diy_fp) {
|
| + uint64_t significand = diy_fp.f();
|
| + int exponent = diy_fp.e();
|
| + while (significand > kHiddenBit + kSignificandMask) {
|
| + significand >>= 1;
|
| + exponent++;
|
| + }
|
| + if (exponent >= kMaxExponent) {
|
| + return kInfinity;
|
| + }
|
| + if (exponent < kDenormalExponent) {
|
| + return 0;
|
| + }
|
| + while (exponent > kDenormalExponent && (significand & kHiddenBit) == 0) {
|
| + significand <<= 1;
|
| + exponent--;
|
| + }
|
| + uint64_t biased_exponent;
|
| + if (exponent == kDenormalExponent && (significand & kHiddenBit) == 0) {
|
| + biased_exponent = 0;
|
| + } else {
|
| + biased_exponent = static_cast<uint64_t>(exponent + kExponentBias);
|
| + }
|
| + return (significand & kSignificandMask) |
|
| + (biased_exponent << kPhysicalSignificandSize);
|
| + }
|
| +};
|
|
|
| } // namespace double_conversion
|
|
|
| -} // namespace WTF
|
| +} // namespace WTF
|
|
|
| #endif // DOUBLE_CONVERSION_DOUBLE_H_
|
|
|