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Patch by Chad Netzer (with significant change):

Browse source 
- range() now works even if the arguments are longs with magnitude
  larger than sys.maxint, as long as the total length of the sequence
  fits.  E.g., range(2**100, 2**101, 2**100) is the following list:
  [1267650600228229401496703205376L].  (SF patch #707427.)
This commit is contained in:
Guido van Rossum 2003-04-11 18:43:06 +00:00
parent a1ce93f87c
commit efbbb1c602
3 changed files with 230 additions and 5 deletions
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195
Python/bltinmodule.c
View file

@ -1252,6 +1252,186 @@ With two arguments, equivalent to x**y. With three arguments,\n\
equivalent to (x**y) % z, but may be more efficient (e.g. for longs).");
/* Return number of items in range (lo, hi, step), when arguments are
* PyInt or PyLong objects. step > 0 required. Return a value < 0 if
* & only if the true value is too large to fit in a signed long.
* Arguments MUST return 1 with either PyInt_Check() or
* PyLong_Check(). Return -1 when there is an error.
*/
static long
get_len_of_range_longs(PyObject *lo, PyObject *hi, PyObject *step)
{
/* -------------------------------------------------------------
Algorithm is equal to that of get_len_of_range(), but it operates
on PyObjects (which are assumed to be PyLong or PyInt objects).
---------------------------------------------------------------*/
long n;
PyObject *diff = NULL;
PyObject *one = NULL;
PyObject *tmp1 = NULL, *tmp2 = NULL, *tmp3 = NULL;
/* holds sub-expression evaluations */
/* if (lo >= hi), return length of 0. */
if (PyObject_Compare(lo, hi) >= 0)
return 0;
if ((one = PyLong_FromLong(1L)) == NULL)
goto Fail;
if ((tmp1 = PyNumber_Subtract(hi, lo)) == NULL)
goto Fail;
if ((diff = PyNumber_Subtract(tmp1, one)) == NULL)
goto Fail;
if ((tmp2 = PyNumber_FloorDivide(diff, step)) == NULL)
goto Fail;
if ((tmp3 = PyNumber_Add(tmp2, one)) == NULL)
goto Fail;
n = PyLong_AsLong(tmp3);
if (PyErr_Occurred()) { /* Check for Overflow */
PyErr_Clear();
goto Fail;
}
Py_DECREF(tmp3);
Py_DECREF(tmp2);
Py_DECREF(diff);
Py_DECREF(tmp1);
Py_DECREF(one);
return n;
Fail:
Py_XDECREF(tmp3);
Py_XDECREF(tmp2);
Py_XDECREF(diff);
Py_XDECREF(tmp1);
Py_XDECREF(one);
return -1;
}
/* An extension of builtin_range() that handles the case when PyLong
* arguments are given. */
static PyObject *
handle_range_longs(PyObject *self, PyObject *args)
{
PyObject *ilow;
PyObject *ihigh;
PyObject *zero = NULL;
PyObject *istep = NULL;
PyObject *curnum = NULL;
PyObject *v = NULL;
long bign;
int i, n;
int cmp_result;
zero = PyLong_FromLong(0L);
if (zero == NULL)
return NULL;
ilow = zero; /* Default lower bound */
if (!PyArg_ParseTuple(args, "O", &ihigh, &istep)) {
PyErr_Clear();
if (!PyArg_ParseTuple(args,
"OO|O;range() requires 1-3 int arguments",
&ilow, &ihigh, &istep))
goto Fail;
}
if (!PyInt_Check(ilow) && !PyLong_Check(ilow)) {
PyErr_SetString(PyExc_ValueError,
"integer start argument expected, got float.");
goto Fail;
return NULL;
}
if (!PyInt_Check(ihigh) && !PyLong_Check(ihigh)) {
PyErr_SetString(PyExc_ValueError,
"integer end argument expected, got float.");
goto Fail;
return NULL;
}
/* If no istep was supplied, default to 1. */
if (istep == NULL) {
istep = PyLong_FromLong(1L);
if (istep == NULL)
goto Fail;
}
else {
if (!PyInt_Check(istep) && !PyLong_Check(istep)) {
PyErr_SetString(PyExc_ValueError,
"integer step argument expected, got float.");
goto Fail;
}
Py_INCREF(istep);
}
if (PyObject_Cmp(istep, zero, &cmp_result) == -1) {
goto Fail;
}
if (cmp_result == 0) {
PyErr_SetString(PyExc_ValueError,
"range() arg 3 must not be zero");
goto Fail;
}
if (cmp_result > 0)
bign = get_len_of_range_longs(ilow, ihigh, istep);
else {
PyObject *neg_istep = PyNumber_Negative(istep);
if (neg_istep == NULL)
goto Fail;
bign = get_len_of_range_longs(ihigh, ilow, neg_istep);
Py_DECREF(neg_istep);
}
n = (int)bign;
if (bign < 0 || (long)n != bign) {
PyErr_SetString(PyExc_OverflowError,
"range() result has too many items");
goto Fail;
}
v = PyList_New(n);
if (v == NULL)
goto Fail;
curnum = ilow;
Py_INCREF(curnum);
for (i = 0; i < n; i++) {
PyObject *w = PyNumber_Long(curnum);
PyObject *tmp_num;
if (w == NULL)
goto Fail;
PyList_SET_ITEM(v, i, w);
tmp_num = PyNumber_Add(curnum, istep);
if (tmp_num == NULL)
goto Fail;
Py_DECREF(curnum);
curnum = tmp_num;
}
Py_DECREF(curnum);
Py_DECREF(istep);
Py_DECREF(zero);
return v;
Fail:
Py_XDECREF(curnum);
Py_XDECREF(istep);
Py_XDECREF(zero);
Py_XDECREF(v);
return NULL;
}
/* Return number of items in range/xrange (lo, hi, step). step > 0
* required. Return a value < 0 if & only if the true value is too
* large to fit in a signed long.
@ -1293,17 +1473,22 @@ builtin_range(PyObject *self, PyObject *args)
if (PyTuple_Size(args) <= 1) {
if (!PyArg_ParseTuple(args,
"l;range() requires 1-3 int arguments",
&ihigh))
return NULL;
&ihigh)) {
PyErr_Clear();
return handle_range_longs(self, args);
}
}
else {
if (!PyArg_ParseTuple(args,
"ll|l;range() requires 1-3 int arguments",
&ilow, &ihigh, &istep))
return NULL;
&ilow, &ihigh, &istep)) {
PyErr_Clear();
return handle_range_longs(self, args);
}
}
if (istep == 0) {
PyErr_SetString(PyExc_ValueError, "range() arg 3 must not be zero");
PyErr_SetString(PyExc_ValueError,
"range() arg 3 must not be zero");
return NULL;
}
if (istep > 0)