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Merge 64438: hex/oct/bin can show floats exactly.

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This commit is contained in:
Raymond Hettinger 2008-06-22 11:39:13 +00:00
parent dd811a4da7
commit d11a44312f
4 changed files with 63 additions and 1 deletions
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30
Objects/floatobject.c
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@ -1113,6 +1113,36 @@ PyDoc_STRVAR(float_as_integer_ratio_doc,
">>> (-.25).as_integer_ratio()\n"
"(-1, 4)");
PyObject *
_float_to_base(PyObject *v, int base)
{
PyObject *mant, *conv, *result;
double x, fr;
int i, exp;
if (!PyFloat_Check(v)) {
PyErr_BadInternalCall();
return NULL;
}
CONVERT_TO_DOUBLE(v, x);
if (!Py_IS_FINITE(x))
return PyObject_Repr(v);
fr = frexp(x, &exp);
for (i=0; i<300 && fr != floor(fr) ; i++) {
fr *= 2.0;
exp--;
}
mant = PyLong_FromDouble(floor(fr));
if (mant == NULL)
return NULL;
conv = PyNumber_ToBase(mant, base);
Py_DECREF(mant);
if (conv == NULL)
return NULL;
result = PyUnicode_FromFormat("%U * 2.0 ** %d", conv, exp);
Py_DECREF(conv);
return result;
}
static PyObject *
float_subtype_new(PyTypeObject *type, PyObject *args, PyObject *kwds);