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