Commit | Line | Data |
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920dae64 AT |
1 | |
2 | /* Float object interface */ | |
3 | ||
4 | /* | |
5 | PyFloatObject represents a (double precision) floating point number. | |
6 | */ | |
7 | ||
8 | #ifndef Py_FLOATOBJECT_H | |
9 | #define Py_FLOATOBJECT_H | |
10 | #ifdef __cplusplus | |
11 | extern "C" { | |
12 | #endif | |
13 | ||
14 | typedef struct { | |
15 | PyObject_HEAD | |
16 | double ob_fval; | |
17 | } PyFloatObject; | |
18 | ||
19 | PyAPI_DATA(PyTypeObject) PyFloat_Type; | |
20 | ||
21 | #define PyFloat_Check(op) PyObject_TypeCheck(op, &PyFloat_Type) | |
22 | #define PyFloat_CheckExact(op) ((op)->ob_type == &PyFloat_Type) | |
23 | ||
24 | /* Return Python float from string PyObject. Second argument ignored on | |
25 | input, and, if non-NULL, NULL is stored into *junk (this tried to serve a | |
26 | purpose once but can't be made to work as intended). */ | |
27 | PyAPI_FUNC(PyObject *) PyFloat_FromString(PyObject*, char** junk); | |
28 | ||
29 | /* Return Python float from C double. */ | |
30 | PyAPI_FUNC(PyObject *) PyFloat_FromDouble(double); | |
31 | ||
32 | /* Extract C double from Python float. The macro version trades safety for | |
33 | speed. */ | |
34 | PyAPI_FUNC(double) PyFloat_AsDouble(PyObject *); | |
35 | #define PyFloat_AS_DOUBLE(op) (((PyFloatObject *)(op))->ob_fval) | |
36 | ||
37 | /* Write repr(v) into the char buffer argument, followed by null byte. The | |
38 | buffer must be "big enough"; >= 100 is very safe. | |
39 | PyFloat_AsReprString(buf, x) strives to print enough digits so that | |
40 | PyFloat_FromString(buf) then reproduces x exactly. */ | |
41 | PyAPI_FUNC(void) PyFloat_AsReprString(char*, PyFloatObject *v); | |
42 | ||
43 | /* Write str(v) into the char buffer argument, followed by null byte. The | |
44 | buffer must be "big enough"; >= 100 is very safe. Note that it's | |
45 | unusual to be able to get back the float you started with from | |
46 | PyFloat_AsString's result -- use PyFloat_AsReprString() if you want to | |
47 | preserve precision across conversions. */ | |
48 | PyAPI_FUNC(void) PyFloat_AsString(char*, PyFloatObject *v); | |
49 | ||
50 | /* _PyFloat_{Pack,Unpack}{4,8} | |
51 | * | |
52 | * The struct and pickle (at least) modules need an efficient platform- | |
53 | * independent way to store floating-point values as byte strings. | |
54 | * The Pack routines produce a string from a C double, and the Unpack | |
55 | * routines produce a C double from such a string. The suffix (4 or 8) | |
56 | * specifies the number of bytes in the string. | |
57 | * | |
58 | * Excepting NaNs and infinities (which aren't handled correctly), the 4- | |
59 | * byte format is identical to the IEEE-754 single precision format, and | |
60 | * the 8-byte format to the IEEE-754 double precision format. On non- | |
61 | * IEEE platforms with more precision, or larger dynamic range, than | |
62 | * 754 supports, not all values can be packed; on non-IEEE platforms with | |
63 | * less precision, or smaller dynamic range, not all values can be | |
64 | * unpacked. What happens in such cases is partly accidental (alas). | |
65 | */ | |
66 | ||
67 | /* The pack routines write 4 or 8 bytes, starting at p. le is a bool | |
68 | * argument, true if you want the string in little-endian format (exponent | |
69 | * last, at p+3 or p+7), false if you want big-endian format (exponent | |
70 | * first, at p). | |
71 | * Return value: 0 if all is OK, -1 if error (and an exception is | |
72 | * set, most likely OverflowError). | |
73 | * Bug: What this does is undefined if x is a NaN or infinity. | |
74 | * Bug: -0.0 and +0.0 produce the same string. | |
75 | */ | |
76 | PyAPI_FUNC(int) _PyFloat_Pack4(double x, unsigned char *p, int le); | |
77 | PyAPI_FUNC(int) _PyFloat_Pack8(double x, unsigned char *p, int le); | |
78 | ||
79 | /* The unpack routines read 4 or 8 bytes, starting at p. le is a bool | |
80 | * argument, true if the string is in little-endian format (exponent | |
81 | * last, at p+3 or p+7), false if big-endian (exponent first, at p). | |
82 | * Return value: The unpacked double. On error, this is -1.0 and | |
83 | * PyErr_Occurred() is true (and an exception is set, most likely | |
84 | * OverflowError). | |
85 | * Bug: What this does is undefined if the string represents a NaN or | |
86 | * infinity. | |
87 | */ | |
88 | PyAPI_FUNC(double) _PyFloat_Unpack4(const unsigned char *p, int le); | |
89 | PyAPI_FUNC(double) _PyFloat_Unpack8(const unsigned char *p, int le); | |
90 | ||
91 | ||
92 | #ifdef __cplusplus | |
93 | } | |
94 | #endif | |
95 | #endif /* !Py_FLOATOBJECT_H */ |