ref: c00c60d327168c25e56077c8310cf2380833e9be
dir: /sys/src/cmd/python/Include/floatobject.h/
/* 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) ((op)->ob_type == &PyFloat_Type)
/* 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);
/* 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);
#ifdef __cplusplus
}
#endif
#endif /* !Py_FLOATOBJECT_H */