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95 lines
3.8 KiB
95 lines
3.8 KiB
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/* Float object interface */ |
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/* |
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PyFloatObject represents a (double precision) floating point number. |
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*/ |
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#ifndef Py_FLOATOBJECT_H |
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#define Py_FLOATOBJECT_H |
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#ifdef __cplusplus |
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extern "C" { |
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#endif |
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typedef struct { |
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PyObject_HEAD |
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double ob_fval; |
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} PyFloatObject; |
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PyAPI_DATA(PyTypeObject) PyFloat_Type; |
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#define PyFloat_Check(op) PyObject_TypeCheck(op, &PyFloat_Type) |
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#define PyFloat_CheckExact(op) ((op)->ob_type == &PyFloat_Type) |
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/* Return Python float from string PyObject. Second argument ignored on |
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input, and, if non-NULL, NULL is stored into *junk (this tried to serve a |
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purpose once but can't be made to work as intended). */ |
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PyAPI_FUNC(PyObject *) PyFloat_FromString(PyObject*, char** junk); |
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/* Return Python float from C double. */ |
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PyAPI_FUNC(PyObject *) PyFloat_FromDouble(double); |
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/* Extract C double from Python float. The macro version trades safety for |
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speed. */ |
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PyAPI_FUNC(double) PyFloat_AsDouble(PyObject *); |
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#define PyFloat_AS_DOUBLE(op) (((PyFloatObject *)(op))->ob_fval) |
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/* Write repr(v) into the char buffer argument, followed by null byte. The |
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buffer must be "big enough"; >= 100 is very safe. |
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PyFloat_AsReprString(buf, x) strives to print enough digits so that |
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PyFloat_FromString(buf) then reproduces x exactly. */ |
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PyAPI_FUNC(void) PyFloat_AsReprString(char*, PyFloatObject *v); |
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/* Write str(v) into the char buffer argument, followed by null byte. The |
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buffer must be "big enough"; >= 100 is very safe. Note that it's |
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unusual to be able to get back the float you started with from |
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PyFloat_AsString's result -- use PyFloat_AsReprString() if you want to |
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preserve precision across conversions. */ |
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PyAPI_FUNC(void) PyFloat_AsString(char*, PyFloatObject *v); |
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/* _PyFloat_{Pack,Unpack}{4,8} |
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* |
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* The struct and pickle (at least) modules need an efficient platform- |
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* independent way to store floating-point values as byte strings. |
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* The Pack routines produce a string from a C double, and the Unpack |
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* routines produce a C double from such a string. The suffix (4 or 8) |
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* specifies the number of bytes in the string. |
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* |
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* Excepting NaNs and infinities (which aren't handled correctly), the 4- |
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* byte format is identical to the IEEE-754 single precision format, and |
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* the 8-byte format to the IEEE-754 double precision format. On non- |
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* IEEE platforms with more precision, or larger dynamic range, than |
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* 754 supports, not all values can be packed; on non-IEEE platforms with |
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* less precision, or smaller dynamic range, not all values can be |
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* unpacked. What happens in such cases is partly accidental (alas). |
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*/ |
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/* The pack routines write 4 or 8 bytes, starting at p. le is a bool |
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* argument, true if you want the string in little-endian format (exponent |
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* last, at p+3 or p+7), false if you want big-endian format (exponent |
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* first, at p). |
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* Return value: 0 if all is OK, -1 if error (and an exception is |
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* set, most likely OverflowError). |
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* Bug: What this does is undefined if x is a NaN or infinity. |
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* Bug: -0.0 and +0.0 produce the same string. |
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*/ |
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PyAPI_FUNC(int) _PyFloat_Pack4(double x, unsigned char *p, int le); |
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PyAPI_FUNC(int) _PyFloat_Pack8(double x, unsigned char *p, int le); |
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/* The unpack routines read 4 or 8 bytes, starting at p. le is a bool |
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* argument, true if the string is in little-endian format (exponent |
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* last, at p+3 or p+7), false if big-endian (exponent first, at p). |
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* Return value: The unpacked double. On error, this is -1.0 and |
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* PyErr_Occurred() is true (and an exception is set, most likely |
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* OverflowError). |
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* Bug: What this does is undefined if the string represents a NaN or |
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* infinity. |
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*/ |
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PyAPI_FUNC(double) _PyFloat_Unpack4(const unsigned char *p, int le); |
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PyAPI_FUNC(double) _PyFloat_Unpack8(const unsigned char *p, int le); |
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#ifdef __cplusplus |
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} |
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#endif |
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#endif /* !Py_FLOATOBJECT_H */
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