cpython/Objects/rangeobject.c

336 lines
6.5 KiB
C

/* Range object implementation */
#include "Python.h"
#include "structmember.h"
#include <string.h>
typedef struct {
PyObject_HEAD
long start;
long step;
long len;
int reps;
long totlen;
} rangeobject;
static int
long_mul(long i, long j, long *kk)
{
PyObject *a;
PyObject *b;
PyObject *c;
if ((a = PyInt_FromLong(i)) == NULL)
return 0;
if ((b = PyInt_FromLong(j)) == NULL)
return 0;
c = PyNumber_Multiply(a, b);
Py_DECREF(a);
Py_DECREF(b);
if (c == NULL)
return 0;
*kk = PyInt_AS_LONG(c);
Py_DECREF(c);
if (*kk > INT_MAX) {
PyErr_SetString(PyExc_OverflowError,
"integer multiplication");
return 0;
}
else
return 1;
}
PyObject *
PyRange_New(long start, long len, long step, int reps)
{
long totlen = -1;
rangeobject *obj = PyObject_NEW(rangeobject, &PyRange_Type);
if (obj == NULL)
return NULL;
if (len == 0 || reps <= 0) {
start = 0;
len = 0;
step = 1;
reps = 1;
totlen = 0;
}
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;
}
if (! long_mul(len, (long) reps, &totlen)) {
if(!PyErr_ExceptionMatches(PyExc_OverflowError))
return NULL;
PyErr_Clear();
totlen = -1;
}
}
obj->start = start;
obj->len = len;
obj->step = step;
obj->reps = reps;
obj->totlen = totlen;
return (PyObject *) obj;
}
static void
range_dealloc(rangeobject *r)
{
PyObject_DEL(r);
}
static PyObject *
range_item(rangeobject *r, int i)
{
if (i < 0 || i >= r->totlen)
if (r->totlen!=-1) {
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 (r->totlen == -1)
PyErr_SetString(PyExc_OverflowError,
"xrange object has too many items");
return r->totlen;
}
static PyObject *
range_repr(rangeobject *r)
{
/* buffers must be big enough to hold 3 longs + an int +
* a bit of "(xrange(...) * ...)" text.
*/
char buf1[250];
char buf2[250];
if (r->start == 0 && r->step == 1)
sprintf(buf1, "xrange(%ld)", r->start + r->len * r->step);
else if (r->step == 1)
sprintf(buf1, "xrange(%ld, %ld)",
r->start,
r->start + r->len * r->step);
else
sprintf(buf1, "xrange(%ld, %ld, %ld)",
r->start,
r->start + r->len * r->step,
r->step);
if (r->reps != 1)
sprintf(buf2, "(%s * %d)", buf1, r->reps);
return PyString_FromString(r->reps == 1 ? buf1 : buf2);
}
static PyObject *
range_concat(rangeobject *r, PyObject *obj)
{
PyErr_SetString(PyExc_TypeError, "cannot concatenate xrange objects");
return NULL;
}
static PyObject *
range_repeat(rangeobject *r, int n)
{
long lreps = 0;
if (n <= 0)
return (PyObject *) PyRange_New(0, 0, 1, 1);
else if (n == 1) {
Py_INCREF(r);
return (PyObject *) r;
}
else if (! long_mul((long) r->reps, (long) n, &lreps))
return NULL;
else
return (PyObject *) PyRange_New(
r->start,
r->len,
r->step,
(int) lreps);
}
static int
range_compare(rangeobject *r1, rangeobject *r2)
{
if (r1->start != r2->start)
return r1->start - r2->start;
else if (r1->step != r2->step)
return r1->step - r2->step;
else if (r1->len != r2->len)
return r1->len - r2->len;
else
return r1->reps - r2->reps;
}
static PyObject *
range_slice(rangeobject *r, int low, int high)
{
if (r->reps != 1) {
PyErr_SetString(PyExc_TypeError,
"cannot slice a replicated xrange");
return NULL;
}
if (low < 0)
low = 0;
else if (low > r->len)
low = r->len;
if (high < 0)
high = 0;
if (high < low)
high = low;
else if (high > r->len)
high = r->len;
if (low == 0 && high == r->len) {
Py_INCREF(r);
return (PyObject *) r;
}
return (PyObject *) PyRange_New(
low * r->step + r->start,
high - low,
r->step,
1);
}
static PyObject *
range_tolist(rangeobject *self, PyObject *args)
{
PyObject *thelist;
int j;
if (! PyArg_ParseTuple(args, ":tolist"))
return NULL;
if (self->totlen == -1)
return PyErr_NoMemory();
if ((thelist = PyList_New(self->totlen)) == NULL)
return NULL;
for (j = 0; j < self->totlen; ++j)
if ((PyList_SetItem(thelist, j, (PyObject *) PyInt_FromLong(
self->start + (j % self->len) * self->step))) < 0)
return NULL;
return thelist;
}
static PyObject *
range_getattr(rangeobject *r, char *name)
{
PyObject *result;
static PyMethodDef range_methods[] = {
{"tolist", (PyCFunction)range_tolist, METH_VARARGS,
"tolist() -> list\n"
"Return a list object with the same values."},
{NULL, NULL}
};
static struct memberlist range_members[] = {
{"step", T_LONG, offsetof(rangeobject, step), RO},
{"start", T_LONG, offsetof(rangeobject, start), RO},
{"stop", T_LONG, 0, RO},
{NULL, 0, 0, 0}
};
result = Py_FindMethod(range_methods, (PyObject *) r, name);
if (result == NULL) {
PyErr_Clear();
if (strcmp("stop", name) == 0)
result = PyInt_FromLong(r->start + (r->len * r->step));
else
result = PyMember_Get((char *)r, range_members, name);
}
return result;
}
static int
range_contains(rangeobject *r, PyObject *obj)
{
long num = PyInt_AsLong(obj);
if (num < 0 && PyErr_Occurred())
return -1;
if (r->step > 0) {
if ((num < r->start) || ((num - r->start) % r->step))
return 0;
if (num >= (r->start + (r->len * r->step)))
return 0;
}
else {
if ((num > r->start) || ((num - r->start) % r->step))
return 0;
if (num <= (r->start + (r->len * r->step)))
return 0;
}
return 1;
}
static PySequenceMethods range_as_sequence = {
(inquiry)range_length, /*sq_length*/
(binaryfunc)range_concat, /*sq_concat*/
(intargfunc)range_repeat, /*sq_repeat*/
(intargfunc)range_item, /*sq_item*/
(intintargfunc)range_slice, /*sq_slice*/
0, /*sq_ass_item*/
0, /*sq_ass_slice*/
(objobjproc)range_contains, /*sq_contains*/
};
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)range_dealloc, /*tp_dealloc*/
0, /*tp_print*/
(getattrfunc)range_getattr, /*tp_getattr*/
0, /*tp_setattr*/
(cmpfunc)range_compare, /*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*/
};