mirror of
https://github.com/python/cpython.git
synced 2025-10-31 13:41:24 +00:00
c4c453f5ae
Also, added more regression tests to cover the new type and test its conformity with range().
296 lines
7.7 KiB
C
296 lines
7.7 KiB
C
|
|
/* Range object implementation */
|
|
|
|
#include "Python.h"
|
|
|
|
typedef struct {
|
|
PyObject_HEAD
|
|
long start;
|
|
long step;
|
|
long len;
|
|
} rangeobject;
|
|
|
|
PyObject *
|
|
PyRange_New(long start, long len, long step, int reps)
|
|
{
|
|
rangeobject *obj;
|
|
|
|
if (reps != 1) {
|
|
PyErr_SetString(PyExc_ValueError,
|
|
"PyRange_New's 'repetitions' argument must be 1");
|
|
return NULL;
|
|
}
|
|
|
|
obj = PyObject_New(rangeobject, &PyRange_Type);
|
|
if (obj == NULL)
|
|
return NULL;
|
|
|
|
if (len == 0) {
|
|
start = 0;
|
|
len = 0;
|
|
step = 1;
|
|
}
|
|
else {
|
|
long last = start + (len - 1) * step;
|
|
if ((step > 0) ?
|
|
(last > (PyInt_GetMax() - step)) :
|
|
(last < (-1 - PyInt_GetMax() - step))) {
|
|
PyErr_SetString(PyExc_OverflowError,
|
|
"integer addition");
|
|
return NULL;
|
|
}
|
|
}
|
|
obj->start = start;
|
|
obj->len = len;
|
|
obj->step = step;
|
|
|
|
return (PyObject *) obj;
|
|
}
|
|
|
|
/* 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.
|
|
*/
|
|
static long
|
|
get_len_of_range(long lo, long hi, long step)
|
|
{
|
|
/* -------------------------------------------------------------
|
|
If lo >= hi, the range is empty.
|
|
Else if n values are in the range, the last one is
|
|
lo + (n-1)*step, which must be <= hi-1. Rearranging,
|
|
n <= (hi - lo - 1)/step + 1, so taking the floor of the RHS gives
|
|
the proper value. Since lo < hi in this case, hi-lo-1 >= 0, so
|
|
the RHS is non-negative and so truncation is the same as the
|
|
floor. Letting M be the largest positive long, the worst case
|
|
for the RHS numerator is hi=M, lo=-M-1, and then
|
|
hi-lo-1 = M-(-M-1)-1 = 2*M. Therefore unsigned long has enough
|
|
precision to compute the RHS exactly.
|
|
---------------------------------------------------------------*/
|
|
long n = 0;
|
|
if (lo < hi) {
|
|
unsigned long uhi = (unsigned long)hi;
|
|
unsigned long ulo = (unsigned long)lo;
|
|
unsigned long diff = uhi - ulo - 1;
|
|
n = (long)(diff / (unsigned long)step + 1);
|
|
}
|
|
return n;
|
|
}
|
|
|
|
static PyObject *
|
|
range_new(PyTypeObject *type, PyObject *args, PyObject *kw)
|
|
{
|
|
long ilow = 0, ihigh = 0, istep = 1;
|
|
long n;
|
|
|
|
if (PyTuple_Size(args) <= 1) {
|
|
if (!PyArg_ParseTuple(args,
|
|
"l;xrange() requires 1-3 int arguments",
|
|
&ihigh))
|
|
return NULL;
|
|
}
|
|
else {
|
|
if (!PyArg_ParseTuple(args,
|
|
"ll|l;xrange() requires 1-3 int arguments",
|
|
&ilow, &ihigh, &istep))
|
|
return NULL;
|
|
}
|
|
if (istep == 0) {
|
|
PyErr_SetString(PyExc_ValueError, "xrange() arg 3 must not be zero");
|
|
return NULL;
|
|
}
|
|
if (istep > 0)
|
|
n = get_len_of_range(ilow, ihigh, istep);
|
|
else
|
|
n = get_len_of_range(ihigh, ilow, -istep);
|
|
if (n < 0) {
|
|
PyErr_SetString(PyExc_OverflowError,
|
|
"xrange() result has too many items");
|
|
return NULL;
|
|
}
|
|
return PyRange_New(ilow, n, istep, 1);
|
|
}
|
|
|
|
static char range_doc[] =
|
|
"xrange([start,] stop[, step]) -> xrange object\n\
|
|
\n\
|
|
Like range(), but instead of returning a list, returns an object that\n\
|
|
generates the numbers in the range on demand. This is slightly slower\n\
|
|
than range() but more memory efficient.";
|
|
|
|
static PyObject *
|
|
range_item(rangeobject *r, int i)
|
|
{
|
|
if (i < 0 || i >= r->len) {
|
|
PyErr_SetString(PyExc_IndexError,
|
|
"xrange object index out of range");
|
|
return NULL;
|
|
}
|
|
return PyInt_FromLong(r->start + (i % r->len) * r->step);
|
|
}
|
|
|
|
static int
|
|
range_length(rangeobject *r)
|
|
{
|
|
return r->len;
|
|
}
|
|
|
|
static PyObject *
|
|
range_repr(rangeobject *r)
|
|
{
|
|
PyObject *rtn;
|
|
|
|
if (r->start == 0 && r->step == 1)
|
|
rtn = PyString_FromFormat("xrange(%ld)",
|
|
r->start + r->len * r->step);
|
|
|
|
else if (r->step == 1)
|
|
rtn = PyString_FromFormat("xrange(%ld, %ld)",
|
|
r->start,
|
|
r->start + r->len * r->step);
|
|
|
|
else
|
|
rtn = PyString_FromFormat("xrange(%ld, %ld, %ld)",
|
|
r->start,
|
|
r->start + r->len * r->step,
|
|
r->step);
|
|
return rtn;
|
|
}
|
|
|
|
static PySequenceMethods range_as_sequence = {
|
|
(inquiry)range_length, /* sq_length */
|
|
0, /* sq_concat */
|
|
0, /* sq_repeat */
|
|
(intargfunc)range_item, /* sq_item */
|
|
0, /* sq_slice */
|
|
};
|
|
|
|
staticforward PyObject * range_iter(PyObject *seq);
|
|
|
|
PyTypeObject PyRange_Type = {
|
|
PyObject_HEAD_INIT(&PyType_Type)
|
|
0, /* Number of items for varobject */
|
|
"xrange", /* Name of this type */
|
|
sizeof(rangeobject), /* Basic object size */
|
|
0, /* Item size for varobject */
|
|
(destructor)PyObject_Del, /* tp_dealloc */
|
|
0, /* tp_print */
|
|
0, /* tp_getattr */
|
|
0, /* tp_setattr */
|
|
0, /* tp_compare */
|
|
(reprfunc)range_repr, /* tp_repr */
|
|
0, /* tp_as_number */
|
|
&range_as_sequence, /* tp_as_sequence */
|
|
0, /* tp_as_mapping */
|
|
0, /* tp_hash */
|
|
0, /* tp_call */
|
|
0, /* tp_str */
|
|
0, /* tp_getattro */
|
|
0, /* tp_setattro */
|
|
0, /* tp_as_buffer */
|
|
Py_TPFLAGS_DEFAULT, /* tp_flags */
|
|
range_doc, /* tp_doc */
|
|
0, /* tp_traverse */
|
|
0, /* tp_clear */
|
|
0, /* tp_richcompare */
|
|
0, /* tp_weaklistoffset */
|
|
(getiterfunc)range_iter, /* tp_iter */
|
|
0, /* tp_iternext */
|
|
0, /* tp_methods */
|
|
0, /* tp_members */
|
|
0, /* tp_getset */
|
|
0, /* tp_base */
|
|
0, /* tp_dict */
|
|
0, /* tp_descr_get */
|
|
0, /* tp_descr_set */
|
|
0, /* tp_dictoffset */
|
|
0, /* tp_init */
|
|
0, /* tp_alloc */
|
|
range_new, /* tp_new */
|
|
};
|
|
|
|
/*********************** Xrange Iterator **************************/
|
|
|
|
typedef struct {
|
|
PyObject_HEAD
|
|
long index;
|
|
long start;
|
|
long step;
|
|
long len;
|
|
} rangeiterobject;
|
|
|
|
PyTypeObject Pyrangeiter_Type;
|
|
|
|
PyObject *
|
|
range_iter(PyObject *seq)
|
|
{
|
|
rangeiterobject *it;
|
|
|
|
if (!PyRange_Check(seq)) {
|
|
PyErr_BadInternalCall();
|
|
return NULL;
|
|
}
|
|
it = PyObject_New(rangeiterobject, &Pyrangeiter_Type);
|
|
if (it == NULL)
|
|
return NULL;
|
|
it->index = 0;
|
|
it->start = ((rangeobject *)seq)->start;
|
|
it->step = ((rangeobject *)seq)->step;
|
|
it->len = ((rangeobject *)seq)->len;
|
|
return (PyObject *)it;
|
|
}
|
|
|
|
static PyObject *
|
|
rangeiter_getiter(PyObject *it)
|
|
{
|
|
Py_INCREF(it);
|
|
return it;
|
|
}
|
|
|
|
static PyObject *
|
|
rangeiter_next(rangeiterobject *r)
|
|
{
|
|
if (r->index < r->len)
|
|
return PyInt_FromLong(r->start + (r->index++) * r->step);
|
|
PyErr_SetObject(PyExc_StopIteration, Py_None);
|
|
return NULL;
|
|
}
|
|
|
|
static PyMethodDef rangeiter_methods[] = {
|
|
{"next", (PyCFunction)rangeiter_next, METH_NOARGS,
|
|
"it.next() -- get the next value, or raise StopIteration"},
|
|
{NULL, NULL} /* sentinel */
|
|
};
|
|
|
|
PyTypeObject Pyrangeiter_Type = {
|
|
PyObject_HEAD_INIT(&PyType_Type)
|
|
0, /* ob_size */
|
|
"rangeiterator", /* tp_name */
|
|
sizeof(rangeiterobject), /* tp_basicsize */
|
|
0, /* tp_itemsize */
|
|
/* methods */
|
|
(destructor)PyObject_Del, /* tp_dealloc */
|
|
0, /* tp_print */
|
|
0, /* tp_getattr */
|
|
0, /* tp_setattr */
|
|
0, /* tp_compare */
|
|
0, /* tp_repr */
|
|
0, /* tp_as_number */
|
|
0, /* tp_as_sequence */
|
|
0, /* tp_as_mapping */
|
|
0, /* tp_hash */
|
|
0, /* tp_call */
|
|
0, /* tp_str */
|
|
PyObject_GenericGetAttr, /* tp_getattro */
|
|
0, /* tp_setattro */
|
|
0, /* tp_as_buffer */
|
|
Py_TPFLAGS_DEFAULT, /* tp_flags */
|
|
0, /* tp_doc */
|
|
0, /* tp_traverse */
|
|
0, /* tp_clear */
|
|
0, /* tp_richcompare */
|
|
0, /* tp_weaklistoffset */
|
|
(getiterfunc)rangeiter_getiter, /* tp_iter */
|
|
(iternextfunc)rangeiter_next, /* tp_iternext */
|
|
rangeiter_methods, /* tp_methods */
|
|
};
|
|
|