91 lines
3.3 KiB
C++
91 lines
3.3 KiB
C++
// Copyright (C) 2011 Milo Yip
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//
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// Permission is hereby granted, free of charge, to any person obtaining a copy
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// of this software and associated documentation files (the "Software"), to deal
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// in the Software without restriction, including without limitation the rights
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// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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// copies of the Software, and to permit persons to whom the Software is
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// furnished to do so, subject to the following conditions:
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//
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// The above copyright notice and this permission notice shall be included in
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// all copies or substantial portions of the Software.
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//
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// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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// THE SOFTWARE.
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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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namespace rapidjson {
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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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double PreviousPositiveDouble() const {
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RAPIDJSON_ASSERT(!Sign());
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if (d == 0.0)
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return 0.0;
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else
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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 ((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 IsNormal() const { return (u & kExponentMask) != 0 || Significand() == 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 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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} // namespace rapidjson
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#endif // RAPIDJSON_IEEE754_
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