NCBI C++ ToolKit
ieee754.h
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5 // Licensed under the MIT License (the "License"); you may not use this file except
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14 
15 #ifndef RAPIDJSON_IEEE754_
16 #define RAPIDJSON_IEEE754_
17 
18 #include "../rapidjson.h"
19 
21 namespace internal {
22 
23 class Double {
24 public:
25  Double() {}
26  Double(double d) : d_(d) {}
27  Double(uint64_t u) : u_(u) {}
28 
29  double Value() const { return d_; }
30  uint64_t Uint64Value() const { return u_; }
31 
32  double NextPositiveDouble() const {
33  RAPIDJSON_ASSERT(!Sign());
34  return Double(u_ + 1).Value();
35  }
36 
37  bool Sign() const { return (u_ & kSignMask) != 0; }
38  uint64_t Significand() const { return u_ & kSignificandMask; }
39  int Exponent() const { return static_cast<int>(((u_ & kExponentMask) >> kSignificandSize) - kExponentBias); }
40 
41  bool IsNan() const { return (u_ & kExponentMask) == kExponentMask && Significand() != 0; }
42  bool IsInf() const { return (u_ & kExponentMask) == kExponentMask && Significand() == 0; }
43  bool IsNanOrInf() const { return (u_ & kExponentMask) == kExponentMask; }
44  bool IsNormal() const { return (u_ & kExponentMask) != 0 || Significand() == 0; }
45  bool IsZero() const { return (u_ & (kExponentMask | kSignificandMask)) == 0; }
46 
47  uint64_t IntegerSignificand() const { return IsNormal() ? Significand() | kHiddenBit : Significand(); }
48  int IntegerExponent() const { return (IsNormal() ? Exponent() : kDenormalExponent) - kSignificandSize; }
49  uint64_t ToBias() const { return (u_ & kSignMask) ? ~u_ + 1 : u_ | kSignMask; }
50 
51  static int EffectiveSignificandSize(int order) {
52  if (order >= -1021)
53  return 53;
54  else if (order <= -1074)
55  return 0;
56  else
57  return order + 1074;
58  }
59 
60 private:
61  static const int kSignificandSize = 52;
62  static const int kExponentBias = 0x3FF;
63  static const int kDenormalExponent = 1 - kExponentBias;
64  static const uint64_t kSignMask = RAPIDJSON_UINT64_C2(0x80000000, 0x00000000);
65  static const uint64_t kExponentMask = RAPIDJSON_UINT64_C2(0x7FF00000, 0x00000000);
66  static const uint64_t kSignificandMask = RAPIDJSON_UINT64_C2(0x000FFFFF, 0xFFFFFFFF);
67  static const uint64_t kHiddenBit = RAPIDJSON_UINT64_C2(0x00100000, 0x00000000);
68 
69  union {
70  double d_;
72  };
73 };
74 
75 } // namespace internal
77 
78 #endif // RAPIDJSON_IEEE754_
double NextPositiveDouble() const
Definition: ieee754.h:32
uint64_t ToBias() const
Definition: ieee754.h:49
static int EffectiveSignificandSize(int order)
Definition: ieee754.h:51
bool IsNormal() const
Definition: ieee754.h:44
int IntegerExponent() const
Definition: ieee754.h:48
uint64_t IntegerSignificand() const
Definition: ieee754.h:47
double Value() const
Definition: ieee754.h:29
uint64_t Significand() const
Definition: ieee754.h:38
bool IsNanOrInf() const
Definition: ieee754.h:43
uint64_t Uint64Value() const
Definition: ieee754.h:30
Uint8 uint64_t
#define RAPIDJSON_ASSERT(x)
Assertion.
Definition: rapidjson.h:402
#define RAPIDJSON_NAMESPACE_BEGIN
provide custom rapidjson namespace (opening expression)
Definition: rapidjson.h:116
#define RAPIDJSON_NAMESPACE_END
provide custom rapidjson namespace (closing expression)
Definition: rapidjson.h:119
#define RAPIDJSON_UINT64_C2(high32, low32)
Construct a 64-bit literal by a pair of 32-bit integer.
Definition: rapidjson.h:289
Modified on Wed Apr 17 13:09:09 2024 by modify_doxy.py rev. 669887