1
2/* Float object interface */
3
4/*
5PyFloatObject represents a (double precision) floating point number.
6*/
7
8#ifndef Py_FLOATOBJECT_H
9#define Py_FLOATOBJECT_H
10#ifdef __cplusplus
11extern "C" {
12#endif
13
14#ifndef Py_LIMITED_API
15typedef struct {
16 PyObject_HEAD
17 double ob_fval;
18} PyFloatObject;
19#endif
20
21PyAPI_DATA(PyTypeObject) PyFloat_Type;
22
23#define PyFloat_Check(op) PyObject_TypeCheck(op, &PyFloat_Type)
24#define PyFloat_CheckExact(op) Py_IS_TYPE(op, &PyFloat_Type)
25
26#ifdef Py_NAN
27#define Py_RETURN_NAN return PyFloat_FromDouble(Py_NAN)
28#endif
29
30#define Py_RETURN_INF(sign) do \
31 if (copysign(1., sign) == 1.) { \
32 return PyFloat_FromDouble(Py_HUGE_VAL); \
33 } else { \
34 return PyFloat_FromDouble(-Py_HUGE_VAL); \
35 } while(0)
36
37PyAPI_FUNC(double) PyFloat_GetMax(void);
38PyAPI_FUNC(double) PyFloat_GetMin(void);
39PyAPI_FUNC(PyObject *) PyFloat_GetInfo(void);
40
41/* Return Python float from string PyObject. */
42PyAPI_FUNC(PyObject *) PyFloat_FromString(PyObject*);
43
44/* Return Python float from C double. */
45PyAPI_FUNC(PyObject *) PyFloat_FromDouble(double);
46
47/* Extract C double from Python float. The macro version trades safety for
48 speed. */
49PyAPI_FUNC(double) PyFloat_AsDouble(PyObject *);
50#ifndef Py_LIMITED_API
51#define PyFloat_AS_DOUBLE(op) (((PyFloatObject *)(op))->ob_fval)
52#endif
53
54#ifndef Py_LIMITED_API
55/* _PyFloat_{Pack,Unpack}{4,8}
56 *
57 * The struct and pickle (at least) modules need an efficient platform-
58 * independent way to store floating-point values as byte strings.
59 * The Pack routines produce a string from a C double, and the Unpack
60 * routines produce a C double from such a string. The suffix (4 or 8)
61 * specifies the number of bytes in the string.
62 *
63 * On platforms that appear to use (see _PyFloat_Init()) IEEE-754 formats
64 * these functions work by copying bits. On other platforms, the formats the
65 * 4- byte format is identical to the IEEE-754 single precision format, and
66 * the 8-byte format to the IEEE-754 double precision format, although the
67 * packing of INFs and NaNs (if such things exist on the platform) isn't
68 * handled correctly, and attempting to unpack a string containing an IEEE
69 * INF or NaN will raise an exception.
70 *
71 * On non-IEEE platforms with more precision, or larger dynamic range, than
72 * 754 supports, not all values can be packed; on non-IEEE platforms with less
73 * precision, or smaller dynamic range, not all values can be unpacked. What
74 * happens in such cases is partly accidental (alas).
75 */
76
77/* The pack routines write 2, 4 or 8 bytes, starting at p. le is a bool
78 * argument, true if you want the string in little-endian format (exponent
79 * last, at p+1, p+3 or p+7), false if you want big-endian format (exponent
80 * first, at p).
81 * Return value: 0 if all is OK, -1 if error (and an exception is
82 * set, most likely OverflowError).
83 * There are two problems on non-IEEE platforms:
84 * 1): What this does is undefined if x is a NaN or infinity.
85 * 2): -0.0 and +0.0 produce the same string.
86 */
87PyAPI_FUNC(int) _PyFloat_Pack2(double x, unsigned char *p, int le);
88PyAPI_FUNC(int) _PyFloat_Pack4(double x, unsigned char *p, int le);
89PyAPI_FUNC(int) _PyFloat_Pack8(double x, unsigned char *p, int le);
90
91/* The unpack routines read 2, 4 or 8 bytes, starting at p. le is a bool
92 * argument, true if the string is in little-endian format (exponent
93 * last, at p+1, p+3 or p+7), false if big-endian (exponent first, at p).
94 * Return value: The unpacked double. On error, this is -1.0 and
95 * PyErr_Occurred() is true (and an exception is set, most likely
96 * OverflowError). Note that on a non-IEEE platform this will refuse
97 * to unpack a string that represents a NaN or infinity.
98 */
99PyAPI_FUNC(double) _PyFloat_Unpack2(const unsigned char *p, int le);
100PyAPI_FUNC(double) _PyFloat_Unpack4(const unsigned char *p, int le);
101PyAPI_FUNC(double) _PyFloat_Unpack8(const unsigned char *p, int le);
102
103PyAPI_FUNC(void) _PyFloat_DebugMallocStats(FILE* out);
104
105/* Format the object based on the format_spec, as defined in PEP 3101
106 (Advanced String Formatting). */
107PyAPI_FUNC(int) _PyFloat_FormatAdvancedWriter(
108 _PyUnicodeWriter *writer,
109 PyObject *obj,
110 PyObject *format_spec,
111 Py_ssize_t start,
112 Py_ssize_t end);
113#endif /* Py_LIMITED_API */
114
115#ifdef __cplusplus
116}
117#endif
118#endif /* !Py_FLOATOBJECT_H */
119

source code of include/python3.10/floatobject.h