1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
|
/* Float object interface */
/*
PyFloatObject represents a (double precision) floating point number.
*/
#ifndef Py_FLOATOBJECT_H
#define Py_FLOATOBJECT_H
#ifdef __cplusplus
extern "C" {
#endif
typedef struct {
PyObject_HEAD
double ob_fval;
} PyFloatObject;
PyAPI_DATA(PyTypeObject) PyFloat_Type;
#define PyFloat_Check(op) PyObject_TypeCheck(op, &PyFloat_Type)
#define PyFloat_CheckExact(op) (Py_TYPE(op) == &PyFloat_Type)
/* The str() precision PyFloat_STR_PRECISION is chosen so that in most cases,
the rounding noise created by various operations is suppressed, while
giving plenty of precision for practical use. */
#define PyFloat_STR_PRECISION 12
#ifdef Py_NAN
#define Py_RETURN_NAN return PyFloat_FromDouble(Py_NAN)
#endif
#define Py_RETURN_INF(sign) do \
if (copysign(1., sign) == 1.) { \
return PyFloat_FromDouble(Py_HUGE_VAL); \
} else { \
return PyFloat_FromDouble(-Py_HUGE_VAL); \
} while(0)
PyAPI_FUNC(double) PyFloat_GetMax(void);
PyAPI_FUNC(double) PyFloat_GetMin(void);
PyAPI_FUNC(PyObject *) PyFloat_GetInfo(void);
/* Return Python float from string PyObject. Second argument ignored on
input, and, if non-NULL, NULL is stored into *junk (this tried to serve a
purpose once but can't be made to work as intended). */
PyAPI_FUNC(PyObject *) PyFloat_FromString(PyObject*, char** junk);
/* Return Python float from C double. */
PyAPI_FUNC(PyObject *) PyFloat_FromDouble(double);
/* Extract C double from Python float. The macro version trades safety for
speed. */
PyAPI_FUNC(double) PyFloat_AsDouble(PyObject *);
#define PyFloat_AS_DOUBLE(op) (((PyFloatObject *)(op))->ob_fval)
/* Write repr(v) into the char buffer argument, followed by null byte. The
buffer must be "big enough"; >= 100 is very safe.
PyFloat_AsReprString(buf, x) strives to print enough digits so that
PyFloat_FromString(buf) then reproduces x exactly. */
PyAPI_FUNC(void) PyFloat_AsReprString(char*, PyFloatObject *v);
/* Write str(v) into the char buffer argument, followed by null byte. The
buffer must be "big enough"; >= 100 is very safe. Note that it's
unusual to be able to get back the float you started with from
PyFloat_AsString's result -- use PyFloat_AsReprString() if you want to
preserve precision across conversions. */
PyAPI_FUNC(void) PyFloat_AsString(char*, PyFloatObject *v);
/* _PyFloat_{Pack,Unpack}{4,8}
*
* The struct and pickle (at least) modules need an efficient platform-
* independent way to store floating-point values as byte strings.
* The Pack routines produce a string from a C double, and the Unpack
* routines produce a C double from such a string. The suffix (4 or 8)
* specifies the number of bytes in the string.
*
* On platforms that appear to use (see _PyFloat_Init()) IEEE-754 formats
* these functions work by copying bits. On other platforms, the formats the
* 4- byte format is identical to the IEEE-754 single precision format, and
* the 8-byte format to the IEEE-754 double precision format, although the
* packing of INFs and NaNs (if such things exist on the platform) isn't
* handled correctly, and attempting to unpack a string containing an IEEE
* INF or NaN will raise an exception.
*
* On non-IEEE platforms with more precision, or larger dynamic range, than
* 754 supports, not all values can be packed; on non-IEEE platforms with less
* precision, or smaller dynamic range, not all values can be unpacked. What
* happens in such cases is partly accidental (alas).
*/
/* The pack routines write 4 or 8 bytes, starting at p. le is a bool
* argument, true if you want the string in little-endian format (exponent
* last, at p+3 or p+7), false if you want big-endian format (exponent
* first, at p).
* Return value: 0 if all is OK, -1 if error (and an exception is
* set, most likely OverflowError).
* There are two problems on non-IEEE platforms:
* 1): What this does is undefined if x is a NaN or infinity.
* 2): -0.0 and +0.0 produce the same string.
*/
PyAPI_FUNC(int) _PyFloat_Pack4(double x, unsigned char *p, int le);
PyAPI_FUNC(int) _PyFloat_Pack8(double x, unsigned char *p, int le);
/* Used to get the important decimal digits of a double */
PyAPI_FUNC(int) _PyFloat_Digits(char *buf, double v, int *signum);
PyAPI_FUNC(void) _PyFloat_DigitsInit(void);
/* The unpack routines read 4 or 8 bytes, starting at p. le is a bool
* argument, true if the string is in little-endian format (exponent
* last, at p+3 or p+7), false if big-endian (exponent first, at p).
* Return value: The unpacked double. On error, this is -1.0 and
* PyErr_Occurred() is true (and an exception is set, most likely
* OverflowError). Note that on a non-IEEE platform this will refuse
* to unpack a string that represents a NaN or infinity.
*/
PyAPI_FUNC(double) _PyFloat_Unpack4(const unsigned char *p, int le);
PyAPI_FUNC(double) _PyFloat_Unpack8(const unsigned char *p, int le);
/* free list api */
PyAPI_FUNC(int) PyFloat_ClearFreeList(void);
/* Format the object based on the format_spec, as defined in PEP 3101
(Advanced String Formatting). */
PyAPI_FUNC(PyObject *) _PyFloat_FormatAdvanced(PyObject *obj,
char *format_spec,
Py_ssize_t format_spec_len);
/* Round a C double x to the closest multiple of 10**-ndigits. Returns a
Python float on success, or NULL (with an appropriate exception set) on
failure. Used in builtin_round in bltinmodule.c. */
PyAPI_FUNC(PyObject *) _Py_double_round(double x, int ndigits);
#ifdef __cplusplus
}
#endif
#endif /* !Py_FLOATOBJECT_H */
|