ieee754.h
// 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 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_
RAPIDJSON_ASSERT
#define RAPIDJSON_ASSERT(x)
Assertion.
Definition: rapidjson.h:402
rapidjson::Value
GenericValue< UTF8<> > Value
GenericValue with UTF8 encoding
Definition: document.h:2010
RAPIDJSON_UINT64_C2
#define RAPIDJSON_UINT64_C2(high32, low32)
Construct a 64-bit literal by a pair of 32-bit integer.
Definition: rapidjson.h:289