diff options
Diffstat (limited to 'Modules/mathmodule.c')
| -rw-r--r-- | Modules/mathmodule.c | 50 |
1 files changed, 50 insertions, 0 deletions
diff --git a/Modules/mathmodule.c b/Modules/mathmodule.c index 5520ca9..7ace997 100644 --- a/Modules/mathmodule.c +++ b/Modules/mathmodule.c @@ -512,6 +512,55 @@ PyDoc_STRVAR(math_sum_doc, Return an accurate floating point sum of values in the iterable.\n\ Assumes IEEE-754 floating point arithmetic."); + +static PyObject * +math_factorial(PyObject *self, PyObject *arg) +{ + long i, x; + PyObject *result, *iobj, *newresult; + + if (PyFloat_Check(arg)) { + double dx = PyFloat_AS_DOUBLE((PyFloatObject *)arg); + if (dx != floor(dx)) { + PyErr_SetString(PyExc_ValueError, + "factorial() only accepts integral values"); + return NULL; + } + } + + x = PyInt_AsLong(arg); + if (x == -1 && PyErr_Occurred()) + return NULL; + if (x < 0) { + PyErr_SetString(PyExc_ValueError, + "factorial() not defined for negative values"); + return NULL; + } + + result = (PyObject *)PyInt_FromLong(1); + if (result == NULL) + return NULL; + for (i=1 ; i<=x ; i++) { + iobj = (PyObject *)PyInt_FromLong(i); + if (iobj == NULL) + goto error; + newresult = PyNumber_Multiply(result, iobj); + Py_DECREF(iobj); + if (newresult == NULL) + goto error; + Py_DECREF(result); + result = newresult; + } + return result; + +error: + Py_DECREF(result); + Py_XDECREF(iobj); + return NULL; +} + +PyDoc_STRVAR(math_factorial_doc, "Return n!"); + static PyObject * math_trunc(PyObject *self, PyObject *number) { @@ -949,6 +998,7 @@ static PyMethodDef math_methods[] = { {"degrees", math_degrees, METH_O, math_degrees_doc}, {"exp", math_exp, METH_O, math_exp_doc}, {"fabs", math_fabs, METH_O, math_fabs_doc}, + {"factorial", math_factorial, METH_O, math_factorial_doc}, {"floor", math_floor, METH_O, math_floor_doc}, {"fmod", math_fmod, METH_VARARGS, math_fmod_doc}, {"frexp", math_frexp, METH_O, math_frexp_doc}, |