| // Tencent is pleased to support the open source community by making RapidJSON available. |
| // |
| // Copyright (C) 2015 THL A29 Limited, a Tencent company, and Milo Yip. All rights reserved. |
| // |
| // Licensed under the MIT License (the "License"); you may not use this file except |
| // in compliance with the License. You may obtain a copy of the License at |
| // |
| // http://opensource.org/licenses/MIT |
| // |
| // Unless required by applicable law or agreed to in writing, software distributed |
| // under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR |
| // CONDITIONS OF ANY KIND, either express or implied. See the License for the |
| // specific language governing permissions and limitations under the License. |
| |
| #ifndef RAPIDJSON_IEEE754_ |
| #define RAPIDJSON_IEEE754_ |
| |
| #include "../rapidjson.h" |
| |
| RAPIDJSON_NAMESPACE_BEGIN |
| namespace internal { |
| |
| class Double { |
| public: |
| Double() {} |
| Double(double d) : d_(d) {} |
| Double(uint64_t u) : u_(u) {} |
| |
| double Value() const { return d_; } |
| uint64_t Uint64Value() const { return u_; } |
| |
| double NextPositiveDouble() const { |
| RAPIDJSON_ASSERT(!Sign()); |
| return Double(u_ + 1).Value(); |
| } |
| |
| bool Sign() const { return (u_ & kSignMask) != 0; } |
| uint64_t Significand() const { return u_ & kSignificandMask; } |
| int Exponent() const { return static_cast<int>(((u_ & kExponentMask) >> kSignificandSize) - kExponentBias); } |
| |
| bool IsNan() const { return (u_ & kExponentMask) == kExponentMask && Significand() != 0; } |
| bool IsInf() const { return (u_ & kExponentMask) == kExponentMask && Significand() == 0; } |
| bool IsNanOrInf() const { return (u_ & kExponentMask) == kExponentMask; } |
| bool IsNormal() const { return (u_ & kExponentMask) != 0 || Significand() == 0; } |
| bool IsZero() const { return (u_ & (kExponentMask | kSignificandMask)) == 0; } |
| |
| uint64_t IntegerSignificand() const { return IsNormal() ? Significand() | kHiddenBit : Significand(); } |
| int IntegerExponent() const { return (IsNormal() ? Exponent() : kDenormalExponent) - kSignificandSize; } |
| uint64_t ToBias() const { return (u_ & kSignMask) ? ~u_ + 1 : u_ | kSignMask; } |
| |
| static int EffectiveSignificandSize(int order) { |
| if (order >= -1021) |
| return 53; |
| else if (order <= -1074) |
| return 0; |
| else |
| return order + 1074; |
| } |
| |
| private: |
| static const int kSignificandSize = 52; |
| static const int kExponentBias = 0x3FF; |
| static const int kDenormalExponent = 1 - kExponentBias; |
| static const uint64_t kSignMask = RAPIDJSON_UINT64_C2(0x80000000, 0x00000000); |
| static const uint64_t kExponentMask = RAPIDJSON_UINT64_C2(0x7FF00000, 0x00000000); |
| static const uint64_t kSignificandMask = RAPIDJSON_UINT64_C2(0x000FFFFF, 0xFFFFFFFF); |
| static const uint64_t kHiddenBit = RAPIDJSON_UINT64_C2(0x00100000, 0x00000000); |
| |
| union { |
| double d_; |
| uint64_t u_; |
| }; |
| }; |
| |
| } // namespace internal |
| RAPIDJSON_NAMESPACE_END |
| |
| #endif // RAPIDJSON_IEEE754_ |