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Diffstat (limited to 'external/rapidjson/internal/ieee754.h')
-rw-r--r-- | external/rapidjson/internal/ieee754.h | 77 |
1 files changed, 77 insertions, 0 deletions
diff --git a/external/rapidjson/internal/ieee754.h b/external/rapidjson/internal/ieee754.h new file mode 100644 index 000000000..6890f89e8 --- /dev/null +++ b/external/rapidjson/internal/ieee754.h @@ -0,0 +1,77 @@ +// 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 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 unsigned EffectiveSignificandSize(int order) { + if (order >= -1021) + return 53; + else if (order <= -1074) + return 0; + else + return static_cast<unsigned>(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_ |