2 /* Float object interface */
5 PyFloatObject represents a (double precision) floating point number.
8 #ifndef Py_FLOATOBJECT_H
9 #define Py_FLOATOBJECT_H
19 PyAPI_DATA(PyTypeObject
) PyFloat_Type
;
21 #define PyFloat_Check(op) PyObject_TypeCheck(op, &PyFloat_Type)
22 #define PyFloat_CheckExact(op) (Py_TYPE(op) == &PyFloat_Type)
24 PyAPI_FUNC(double) PyFloat_GetMax(void);
25 PyAPI_FUNC(double) PyFloat_GetMin(void);
26 PyAPI_FUNC(PyObject
*) PyFloat_GetInfo(void);
28 /* Return Python float from string PyObject. Second argument ignored on
29 input, and, if non-NULL, NULL is stored into *junk (this tried to serve a
30 purpose once but can't be made to work as intended). */
31 PyAPI_FUNC(PyObject
*) PyFloat_FromString(PyObject
*, char** junk
);
33 /* Return Python float from C double. */
34 PyAPI_FUNC(PyObject
*) PyFloat_FromDouble(double);
36 /* Extract C double from Python float. The macro version trades safety for
38 PyAPI_FUNC(double) PyFloat_AsDouble(PyObject
*);
39 #define PyFloat_AS_DOUBLE(op) (((PyFloatObject *)(op))->ob_fval)
41 /* Write repr(v) into the char buffer argument, followed by null byte. The
42 buffer must be "big enough"; >= 100 is very safe.
43 PyFloat_AsReprString(buf, x) strives to print enough digits so that
44 PyFloat_FromString(buf) then reproduces x exactly. */
45 PyAPI_FUNC(void) PyFloat_AsReprString(char*, PyFloatObject
*v
);
47 /* Write str(v) into the char buffer argument, followed by null byte. The
48 buffer must be "big enough"; >= 100 is very safe. Note that it's
49 unusual to be able to get back the float you started with from
50 PyFloat_AsString's result -- use PyFloat_AsReprString() if you want to
51 preserve precision across conversions. */
52 PyAPI_FUNC(void) PyFloat_AsString(char*, PyFloatObject
*v
);
54 /* _PyFloat_{Pack,Unpack}{4,8}
56 * The struct and pickle (at least) modules need an efficient platform-
57 * independent way to store floating-point values as byte strings.
58 * The Pack routines produce a string from a C double, and the Unpack
59 * routines produce a C double from such a string. The suffix (4 or 8)
60 * specifies the number of bytes in the string.
62 * On platforms that appear to use (see _PyFloat_Init()) IEEE-754 formats
63 * these functions work by copying bits. On other platforms, the formats the
64 * 4- byte format is identical to the IEEE-754 single precision format, and
65 * the 8-byte format to the IEEE-754 double precision format, although the
66 * packing of INFs and NaNs (if such things exist on the platform) isn't
67 * handled correctly, and attempting to unpack a string containing an IEEE
68 * INF or NaN will raise an exception.
70 * On non-IEEE platforms with more precision, or larger dynamic range, than
71 * 754 supports, not all values can be packed; on non-IEEE platforms with less
72 * precision, or smaller dynamic range, not all values can be unpacked. What
73 * happens in such cases is partly accidental (alas).
76 /* The pack routines write 4 or 8 bytes, starting at p. le is a bool
77 * argument, true if you want the string in little-endian format (exponent
78 * last, at p+3 or p+7), false if you want big-endian format (exponent
80 * Return value: 0 if all is OK, -1 if error (and an exception is
81 * set, most likely OverflowError).
82 * There are two problems on non-IEEE platforms:
83 * 1): What this does is undefined if x is a NaN or infinity.
84 * 2): -0.0 and +0.0 produce the same string.
86 PyAPI_FUNC(int) _PyFloat_Pack4(double x
, unsigned char *p
, int le
);
87 PyAPI_FUNC(int) _PyFloat_Pack8(double x
, unsigned char *p
, int le
);
89 /* Used to get the important decimal digits of a double */
90 PyAPI_FUNC(int) _PyFloat_Digits(char *buf
, double v
, int *signum
);
91 PyAPI_FUNC(void) _PyFloat_DigitsInit(void);
93 /* The unpack routines read 4 or 8 bytes, starting at p. le is a bool
94 * argument, true if the string is in little-endian format (exponent
95 * last, at p+3 or p+7), false if big-endian (exponent first, at p).
96 * Return value: The unpacked double. On error, this is -1.0 and
97 * PyErr_Occurred() is true (and an exception is set, most likely
98 * OverflowError). Note that on a non-IEEE platform this will refuse
99 * to unpack a string that represents a NaN or infinity.
101 PyAPI_FUNC(double) _PyFloat_Unpack4(const unsigned char *p
, int le
);
102 PyAPI_FUNC(double) _PyFloat_Unpack8(const unsigned char *p
, int le
);
105 PyAPI_FUNC(void) PyFloat_CompactFreeList(size_t *, size_t *, size_t *);
110 #endif /* !Py_FLOATOBJECT_H */