Staging
v0.5.1
v0.5.1
https://github.com/python/cpython
Revision 31352c5a304cef1d972aba6e6ec61e89dcadde21 authored by Andrew M. Kuchling on 29 June 2004, 13:17:29 UTC, committed by Andrew M. Kuchling on 29 June 2004, 13:17:29 UTC
1 parent bd3200f
Tip revision: 31352c5a304cef1d972aba6e6ec61e89dcadde21 authored by Andrew M. Kuchling on 29 June 2004, 13:17:29 UTC
Remove unused import. (If it's there for some deep, dark reason, it should have been commented.)
Remove unused import. (If it's there for some deep, dark reason, it should have been commented.)
Tip revision: 31352c5
rangeobject.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);
}
PyDoc_STRVAR(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. For looping, this is \n\
slightly faster than range() and 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)
{
#if LONG_MAX != INT_MAX
if (r->len > INT_MAX) {
PyErr_SetString(PyExc_ValueError,
"xrange object size cannot be reported");
return -1;
}
#endif
return (int)(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 */
};
static PyObject * range_iter(PyObject *seq);
static PyObject * range_reverse(PyObject *seq);
PyDoc_STRVAR(reverse_doc,
"Returns a reverse iterator.");
static PyMethodDef range_methods[] = {
{"__reversed__", (PyCFunction)range_reverse, METH_NOARGS, reverse_doc},
{NULL, NULL} /* sentinel */
};
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 */
PyObject_GenericGetAttr, /* 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 */
range_methods, /* 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;
static PyTypeObject Pyrangeiter_Type;
static 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 *
range_reverse(PyObject *seq)
{
rangeiterobject *it;
long start, step, len;
if (!PyRange_Check(seq)) {
PyErr_BadInternalCall();
return NULL;
}
it = PyObject_New(rangeiterobject, &Pyrangeiter_Type);
if (it == NULL)
return NULL;
start = ((rangeobject *)seq)->start;
step = ((rangeobject *)seq)->step;
len = ((rangeobject *)seq)->len;
it->index = 0;
it->start = start + (len-1) * step;
it->step = -step;
it->len = len;
return (PyObject *)it;
}
static PyObject *
rangeiter_next(rangeiterobject *r)
{
if (r->index < r->len)
return PyInt_FromLong(r->start + (r->index++) * r->step);
return NULL;
}
static int
rangeiter_len(rangeiterobject *r)
{
return r->len - r->index;
}
static PySequenceMethods rangeiter_as_sequence = {
(inquiry)rangeiter_len, /* sq_length */
0, /* sq_concat */
};
static 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 */
&rangeiter_as_sequence, /* 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 */
PyObject_SelfIter, /* tp_iter */
(iternextfunc)rangeiter_next, /* tp_iternext */
0, /* tp_methods */
};
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