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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 {
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 IsNormal() const { return (u_ & kExponentMask) != 0 || Significand() == 0; }
44  bool IsZero() const { return (u_ & (kExponentMask | kSignificandMask)) == 0; }
45 
48  uint64_t ToBias() const { return (u_ & kSignMask) ? ~u_ + 1 : u_ | kSignMask; }
49 
50  static unsigned EffectiveSignificandSize(int order) {
51  if (order >= -1021)
52  return 53;
53  else if (order <= -1074)
54  return 0;
55  else
56  return order + 1074;
57  }
58 
59 private:
60  static const int kSignificandSize = 52;
61  static const int kExponentBias = 0x3FF;
62  static const int kDenormalExponent = 1 - kExponentBias;
63  static const uint64_t kSignMask = RAPIDJSON_UINT64_C2(0x80000000, 0x00000000);
64  static const uint64_t kExponentMask = RAPIDJSON_UINT64_C2(0x7FF00000, 0x00000000);
65  static const uint64_t kSignificandMask = RAPIDJSON_UINT64_C2(0x000FFFFF, 0xFFFFFFFF);
66  static const uint64_t kHiddenBit = RAPIDJSON_UINT64_C2(0x00100000, 0x00000000);
67 
68  union {
69  double d_;
71  };
72 };
73 
74 } // namespace internal
76 
77 #endif // RAPIDJSON_IEEE754_
static const int kSignificandSize
Definition: ieee754.h:60
static unsigned EffectiveSignificandSize(int order)
Definition: ieee754.h:50
uint64_t u_
Definition: ieee754.h:70
#define RAPIDJSON_ASSERT(x)
Assertion.
Definition: rapidjson.h:344
#define RAPIDJSON_UINT64_C2(high32, low32)
Construct a 64-bit literal by a pair of 32-bit integer.
Definition: rapidjson.h:261
#define RAPIDJSON_NAMESPACE_END
provide custom rapidjson namespace (closing expression)
Definition: rapidjson.h:119
Double(uint64_t u)
Definition: ieee754.h:27
Double()
Definition: ieee754.h:25
static const uint64_t kExponentMask
Definition: ieee754.h:64
uint64_t Significand() const
Definition: ieee754.h:38
#define RAPIDJSON_NAMESPACE_BEGIN
provide custom rapidjson namespace (opening expression)
Definition: rapidjson.h:116
static const uint64_t kSignMask
Definition: ieee754.h:63
Double(double d)
Definition: ieee754.h:26
double Value() const
Definition: ieee754.h:29
bool IsInf() const
Definition: ieee754.h:42
bool IsNormal() const
Definition: ieee754.h:43
bool Sign() const
Definition: ieee754.h:37
double NextPositiveDouble() const
Definition: ieee754.h:32
bool IsNan() const
Definition: ieee754.h:41
static const int kDenormalExponent
Definition: ieee754.h:62
double d_
Definition: ieee754.h:69
bool IsZero() const
Definition: ieee754.h:44
unsigned __int64 uint64_t
Definition: stdint.h:90
uint64_t IntegerSignificand() const
Definition: ieee754.h:46
Definition: document.h:390
uint64_t Uint64Value() const
Definition: ieee754.h:30
int IntegerExponent() const
Definition: ieee754.h:47
static const uint64_t kSignificandMask
Definition: ieee754.h:65
Definition: ieee754.h:23
static const int kExponentBias
Definition: ieee754.h:61
static const uint64_t kHiddenBit
Definition: ieee754.h:66
uint64_t ToBias() const
Definition: ieee754.h:48
int Exponent() const
Definition: ieee754.h:39