forked from python/cpython
-
Notifications
You must be signed in to change notification settings - Fork 0
/
sliceobject.c
714 lines (632 loc) · 21 KB
/
sliceobject.c
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
863
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
/*
Written by Jim Hugunin and Chris Chase.
This includes both the singular ellipsis object and slice objects.
Guido, feel free to do whatever you want in the way of copyrights
for this file.
*/
/*
Py_Ellipsis encodes the '...' rubber index token. It is similar to
the Py_NoneStruct in that there is no way to create other objects of
this type and there is exactly one in existence.
*/
#include "Python.h"
#include "pycore_abstract.h" // _PyIndex_Check()
#include "pycore_long.h" // _PyLong_GetZero()
#include "pycore_modsupport.h" // _PyArg_NoKeywords()
#include "pycore_object.h" // _PyObject_GC_TRACK()
static PyObject *
ellipsis_new(PyTypeObject *type, PyObject *args, PyObject *kwargs)
{
if (PyTuple_GET_SIZE(args) || (kwargs && PyDict_GET_SIZE(kwargs))) {
PyErr_SetString(PyExc_TypeError, "EllipsisType takes no arguments");
return NULL;
}
return Py_Ellipsis;
}
static void
ellipsis_dealloc(PyObject *ellipsis)
{
/* This should never get called, but we also don't want to SEGV if
* we accidentally decref Ellipsis out of existence. Instead,
* since Ellipsis is an immortal object, re-set the reference count.
*/
_Py_SetImmortal(ellipsis);
}
static PyObject *
ellipsis_repr(PyObject *op)
{
return PyUnicode_FromString("Ellipsis");
}
static PyObject *
ellipsis_reduce(PyObject *op, PyObject *Py_UNUSED(ignored))
{
return PyUnicode_FromString("Ellipsis");
}
static PyMethodDef ellipsis_methods[] = {
{"__reduce__", ellipsis_reduce, METH_NOARGS, NULL},
{NULL, NULL}
};
PyTypeObject PyEllipsis_Type = {
PyVarObject_HEAD_INIT(&PyType_Type, 0)
"ellipsis", /* tp_name */
0, /* tp_basicsize */
0, /* tp_itemsize */
ellipsis_dealloc, /* tp_dealloc */
0, /* tp_vectorcall_offset */
0, /* tp_getattr */
0, /* tp_setattr */
0, /* tp_as_async */
ellipsis_repr, /* 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 */
0, /* tp_iter */
0, /* tp_iternext */
ellipsis_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 */
ellipsis_new, /* tp_new */
};
PyObject _Py_EllipsisObject = _PyObject_HEAD_INIT(&PyEllipsis_Type);
/* Slice object implementation */
void _PySlice_Fini(PyInterpreterState *interp)
{
PySliceObject *obj = interp->slice_cache;
if (obj != NULL) {
interp->slice_cache = NULL;
PyObject_GC_Del(obj);
}
}
/* start, stop, and step are python objects with None indicating no
index is present.
*/
static PySliceObject *
_PyBuildSlice_Consume2(PyObject *start, PyObject *stop, PyObject *step)
{
assert(start != NULL && stop != NULL && step != NULL);
PyInterpreterState *interp = _PyInterpreterState_GET();
PySliceObject *obj;
if (interp->slice_cache != NULL) {
obj = interp->slice_cache;
interp->slice_cache = NULL;
_Py_NewReference((PyObject *)obj);
}
else {
obj = PyObject_GC_New(PySliceObject, &PySlice_Type);
if (obj == NULL) {
goto error;
}
}
obj->start = start;
obj->stop = stop;
obj->step = Py_NewRef(step);
_PyObject_GC_TRACK(obj);
return obj;
error:
Py_DECREF(start);
Py_DECREF(stop);
return NULL;
}
PyObject *
PySlice_New(PyObject *start, PyObject *stop, PyObject *step)
{
if (step == NULL) {
step = Py_None;
}
if (start == NULL) {
start = Py_None;
}
if (stop == NULL) {
stop = Py_None;
}
return (PyObject *)_PyBuildSlice_Consume2(Py_NewRef(start),
Py_NewRef(stop), step);
}
PyObject *
_PyBuildSlice_ConsumeRefs(PyObject *start, PyObject *stop)
{
assert(start != NULL && stop != NULL);
return (PyObject *)_PyBuildSlice_Consume2(start, stop, Py_None);
}
PyObject *
_PySlice_FromIndices(Py_ssize_t istart, Py_ssize_t istop)
{
PyObject *start, *end, *slice;
start = PyLong_FromSsize_t(istart);
if (!start)
return NULL;
end = PyLong_FromSsize_t(istop);
if (!end) {
Py_DECREF(start);
return NULL;
}
slice = PySlice_New(start, end, NULL);
Py_DECREF(start);
Py_DECREF(end);
return slice;
}
int
PySlice_GetIndices(PyObject *_r, Py_ssize_t length,
Py_ssize_t *start, Py_ssize_t *stop, Py_ssize_t *step)
{
PySliceObject *r = (PySliceObject*)_r;
/* XXX support long ints */
if (r->step == Py_None) {
*step = 1;
} else {
if (!PyLong_Check(r->step)) return -1;
*step = PyLong_AsSsize_t(r->step);
}
if (r->start == Py_None) {
*start = *step < 0 ? length-1 : 0;
} else {
if (!PyLong_Check(r->start)) return -1;
*start = PyLong_AsSsize_t(r->start);
if (*start < 0) *start = length;
}
if (r->stop == Py_None) {
*stop = *step < 0 ? -1 : length;
} else {
if (!PyLong_Check(r->stop)) return -1;
*stop = PyLong_AsSsize_t(r->stop);
if (*stop < 0) *stop = length;
}
if (*stop > length) return -1;
if (*start >= length) return -1;
if (*step == 0) return -1;
return 0;
}
int
PySlice_Unpack(PyObject *_r,
Py_ssize_t *start, Py_ssize_t *stop, Py_ssize_t *step)
{
PySliceObject *r = (PySliceObject*)_r;
/* this is harder to get right than you might think */
static_assert(PY_SSIZE_T_MIN 1 <= -PY_SSIZE_T_MAX,
"-PY_SSIZE_T_MAX < PY_SSIZE_T_MIN 1");
if (r->step == Py_None) {
*step = 1;
}
else {
if (!_PyEval_SliceIndex(r->step, step)) return -1;
if (*step == 0) {
PyErr_SetString(PyExc_ValueError,
"slice step cannot be zero");
return -1;
}
/* Here *step might be -PY_SSIZE_T_MAX-1; in this case we replace it
* with -PY_SSIZE_T_MAX. This doesn't affect the semantics, and it
* guards against later undefined behaviour resulting from code that
* does "step = -step" as part of a slice reversal.
*/
if (*step < -PY_SSIZE_T_MAX)
*step = -PY_SSIZE_T_MAX;
}
if (r->start == Py_None) {
*start = *step < 0 ? PY_SSIZE_T_MAX : 0;
}
else {
if (!_PyEval_SliceIndex(r->start, start)) return -1;
}
if (r->stop == Py_None) {
*stop = *step < 0 ? PY_SSIZE_T_MIN : PY_SSIZE_T_MAX;
}
else {
if (!_PyEval_SliceIndex(r->stop, stop)) return -1;
}
return 0;
}
Py_ssize_t
PySlice_AdjustIndices(Py_ssize_t length,
Py_ssize_t *start, Py_ssize_t *stop, Py_ssize_t step)
{
/* this is harder to get right than you might think */
assert(step != 0);
assert(step >= -PY_SSIZE_T_MAX);
if (*start < 0) {
*start = length;
if (*start < 0) {
*start = (step < 0) ? -1 : 0;
}
}
else if (*start >= length) {
*start = (step < 0) ? length - 1 : length;
}
if (*stop < 0) {
*stop = length;
if (*stop < 0) {
*stop = (step < 0) ? -1 : 0;
}
}
else if (*stop >= length) {
*stop = (step < 0) ? length - 1 : length;
}
if (step < 0) {
if (*stop < *start) {
return (*start - *stop - 1) / (-step) 1;
}
}
else {
if (*start < *stop) {
return (*stop - *start - 1) / step 1;
}
}
return 0;
}
#undef PySlice_GetIndicesEx
int
PySlice_GetIndicesEx(PyObject *_r, Py_ssize_t length,
Py_ssize_t *start, Py_ssize_t *stop, Py_ssize_t *step,
Py_ssize_t *slicelength)
{
if (PySlice_Unpack(_r, start, stop, step) < 0)
return -1;
*slicelength = PySlice_AdjustIndices(length, start, stop, *step);
return 0;
}
static PyObject *
slice_new(PyTypeObject *type, PyObject *args, PyObject *kw)
{
PyObject *start, *stop, *step;
start = stop = step = NULL;
if (!_PyArg_NoKeywords("slice", kw))
return NULL;
if (!PyArg_UnpackTuple(args, "slice", 1, 3, &start, &stop, &step))
return NULL;
/* This swapping of stop and start is to maintain similarity with
range(). */
if (stop == NULL) {
stop = start;
start = NULL;
}
return PySlice_New(start, stop, step);
}
PyDoc_STRVAR(slice_doc,
"slice(stop)\n\
slice(start, stop[, step])\n\
\n\
Create a slice object. This is used for extended slicing (e.g. a[0:10:2]).");
static void
slice_dealloc(PySliceObject *r)
{
PyInterpreterState *interp = _PyInterpreterState_GET();
_PyObject_GC_UNTRACK(r);
Py_DECREF(r->step);
Py_DECREF(r->start);
Py_DECREF(r->stop);
if (interp->slice_cache == NULL) {
interp->slice_cache = r;
}
else {
PyObject_GC_Del(r);
}
}
static PyObject *
slice_repr(PySliceObject *r)
{
return PyUnicode_FromFormat("slice(%R, %R, %R)", r->start, r->stop, r->step);
}
static PyMemberDef slice_members[] = {
{"start", _Py_T_OBJECT, offsetof(PySliceObject, start), Py_READONLY},
{"stop", _Py_T_OBJECT, offsetof(PySliceObject, stop), Py_READONLY},
{"step", _Py_T_OBJECT, offsetof(PySliceObject, step), Py_READONLY},
{0}
};
/* Helper function to convert a slice argument to a PyLong, and raise TypeError
with a suitable message on failure. */
static PyObject*
evaluate_slice_index(PyObject *v)
{
if (_PyIndex_Check(v)) {
return PyNumber_Index(v);
}
else {
PyErr_SetString(PyExc_TypeError,
"slice indices must be integers or "
"None or have an __index__ method");
return NULL;
}
}
/* Compute slice indices given a slice and length. Return -1 on failure. Used
by slice.indices and rangeobject slicing. Assumes that `len` is a
nonnegative instance of PyLong. */
int
_PySlice_GetLongIndices(PySliceObject *self, PyObject *length,
PyObject **start_ptr, PyObject **stop_ptr,
PyObject **step_ptr)
{
PyObject *start=NULL, *stop=NULL, *step=NULL;
PyObject *upper=NULL, *lower=NULL;
int step_is_negative, cmp_result;
/* Convert step to an integer; raise for zero step. */
if (self->step == Py_None) {
step = _PyLong_GetOne();
step_is_negative = 0;
}
else {
int step_sign;
step = evaluate_slice_index(self->step);
if (step == NULL)
goto error;
step_sign = _PyLong_Sign(step);
if (step_sign == 0) {
PyErr_SetString(PyExc_ValueError,
"slice step cannot be zero");
goto error;
}
step_is_negative = step_sign < 0;
}
/* Find lower and upper bounds for start and stop. */
if (step_is_negative) {
lower = PyLong_FromLong(-1L);
if (lower == NULL)
goto error;
upper = PyNumber_Add(length, lower);
if (upper == NULL)
goto error;
}
else {
lower = _PyLong_GetZero();
upper = Py_NewRef(length);
}
/* Compute start. */
if (self->start == Py_None) {
start = Py_NewRef(step_is_negative ? upper : lower);
}
else {
start = evaluate_slice_index(self->start);
if (start == NULL)
goto error;
if (_PyLong_IsNegative((PyLongObject *)start)) {
/* start = length */
PyObject *tmp = PyNumber_Add(start, length);
Py_SETREF(start, tmp);
if (start == NULL)
goto error;
cmp_result = PyObject_RichCompareBool(start, lower, Py_LT);
if (cmp_result < 0)
goto error;
if (cmp_result) {
Py_SETREF(start, Py_NewRef(lower));
}
}
else {
cmp_result = PyObject_RichCompareBool(start, upper, Py_GT);
if (cmp_result < 0)
goto error;
if (cmp_result) {
Py_SETREF(start, Py_NewRef(upper));
}
}
}
/* Compute stop. */
if (self->stop == Py_None) {
stop = Py_NewRef(step_is_negative ? lower : upper);
}
else {
stop = evaluate_slice_index(self->stop);
if (stop == NULL)
goto error;
if (_PyLong_IsNegative((PyLongObject *)stop)) {
/* stop = length */
PyObject *tmp = PyNumber_Add(stop, length);
Py_SETREF(stop, tmp);
if (stop == NULL)
goto error;
cmp_result = PyObject_RichCompareBool(stop, lower, Py_LT);
if (cmp_result < 0)
goto error;
if (cmp_result) {
Py_SETREF(stop, Py_NewRef(lower));
}
}
else {
cmp_result = PyObject_RichCompareBool(stop, upper, Py_GT);
if (cmp_result < 0)
goto error;
if (cmp_result) {
Py_SETREF(stop, Py_NewRef(upper));
}
}
}
*start_ptr = start;
*stop_ptr = stop;
*step_ptr = step;
Py_DECREF(upper);
Py_DECREF(lower);
return 0;
error:
*start_ptr = *stop_ptr = *step_ptr = NULL;
Py_XDECREF(start);
Py_XDECREF(stop);
Py_XDECREF(step);
Py_XDECREF(upper);
Py_XDECREF(lower);
return -1;
}
/* Implementation of slice.indices. */
static PyObject*
slice_indices(PySliceObject* self, PyObject* len)
{
PyObject *start, *stop, *step;
PyObject *length;
int error;
/* Convert length to an integer if necessary; raise for negative length. */
length = PyNumber_Index(len);
if (length == NULL)
return NULL;
if (_PyLong_IsNegative((PyLongObject *)length)) {
PyErr_SetString(PyExc_ValueError,
"length should not be negative");
Py_DECREF(length);
return NULL;
}
error = _PySlice_GetLongIndices(self, length, &start, &stop, &step);
Py_DECREF(length);
if (error == -1)
return NULL;
else
return Py_BuildValue("(NNN)", start, stop, step);
}
PyDoc_STRVAR(slice_indices_doc,
"S.indices(len) -> (start, stop, stride)\n\
\n\
Assuming a sequence of length len, calculate the start and stop\n\
indices, and the stride length of the extended slice described by\n\
S. Out of bounds indices are clipped in a manner consistent with the\n\
handling of normal slices.");
static PyObject *
slice_reduce(PySliceObject* self, PyObject *Py_UNUSED(ignored))
{
return Py_BuildValue("O(OOO)", Py_TYPE(self), self->start, self->stop, self->step);
}
PyDoc_STRVAR(reduce_doc, "Return state information for pickling.");
static PyMethodDef slice_methods[] = {
{"indices", (PyCFunction)slice_indices,
METH_O, slice_indices_doc},
{"__reduce__", (PyCFunction)slice_reduce,
METH_NOARGS, reduce_doc},
{NULL, NULL}
};
static PyObject *
slice_richcompare(PyObject *v, PyObject *w, int op)
{
if (!PySlice_Check(v) || !PySlice_Check(w))
Py_RETURN_NOTIMPLEMENTED;
if (v == w) {
PyObject *res;
/* XXX Do we really need this shortcut?
There's a unit test for it, but is that fair? */
switch (op) {
case Py_EQ:
case Py_LE:
case Py_GE:
res = Py_True;
break;
default:
res = Py_False;
break;
}
return Py_NewRef(res);
}
PyObject *t1 = PyTuple_Pack(3,
((PySliceObject *)v)->start,
((PySliceObject *)v)->stop,
((PySliceObject *)v)->step);
if (t1 == NULL) {
return NULL;
}
PyObject *t2 = PyTuple_Pack(3,
((PySliceObject *)w)->start,
((PySliceObject *)w)->stop,
((PySliceObject *)w)->step);
if (t2 == NULL) {
Py_DECREF(t1);
return NULL;
}
PyObject *res = PyObject_RichCompare(t1, t2, op);
Py_DECREF(t1);
Py_DECREF(t2);
return res;
}
static int
slice_traverse(PySliceObject *v, visitproc visit, void *arg)
{
Py_VISIT(v->start);
Py_VISIT(v->stop);
Py_VISIT(v->step);
return 0;
}
/* code based on tuplehash() of Objects/tupleobject.c */
#if SIZEOF_PY_UHASH_T > 4
#define _PyHASH_XXPRIME_1 ((Py_uhash_t)11400714785074694791ULL)
#define _PyHASH_XXPRIME_2 ((Py_uhash_t)14029467366897019727ULL)
#define _PyHASH_XXPRIME_5 ((Py_uhash_t)2870177450012600261ULL)
#define _PyHASH_XXROTATE(x) ((x << 31) | (x >> 33)) /* Rotate left 31 bits */
#else
#define _PyHASH_XXPRIME_1 ((Py_uhash_t)2654435761UL)
#define _PyHASH_XXPRIME_2 ((Py_uhash_t)2246822519UL)
#define _PyHASH_XXPRIME_5 ((Py_uhash_t)374761393UL)
#define _PyHASH_XXROTATE(x) ((x << 13) | (x >> 19)) /* Rotate left 13 bits */
#endif
static Py_hash_t
slicehash(PySliceObject *v)
{
Py_uhash_t acc = _PyHASH_XXPRIME_5;
#define _PyHASH_SLICE_PART(com) { \
Py_uhash_t lane = PyObject_Hash(v->com); \
if(lane == (Py_uhash_t)-1) { \
return -1; \
} \
acc = lane * _PyHASH_XXPRIME_2; \
acc = _PyHASH_XXROTATE(acc); \
acc *= _PyHASH_XXPRIME_1; \
}
_PyHASH_SLICE_PART(start);
_PyHASH_SLICE_PART(stop);
_PyHASH_SLICE_PART(step);
#undef _PyHASH_SLICE_PART
if(acc == (Py_uhash_t)-1) {
return 1546275796;
}
return acc;
}
PyTypeObject PySlice_Type = {
PyVarObject_HEAD_INIT(&PyType_Type, 0)
"slice", /* Name of this type */
sizeof(PySliceObject), /* Basic object size */
0, /* Item size for varobject */
(destructor)slice_dealloc, /* tp_dealloc */
0, /* tp_vectorcall_offset */
0, /* tp_getattr */
0, /* tp_setattr */
0, /* tp_as_async */
(reprfunc)slice_repr, /* tp_repr */
0, /* tp_as_number */
0, /* tp_as_sequence */
0, /* tp_as_mapping */
(hashfunc)slicehash, /* tp_hash */
0, /* tp_call */
0, /* tp_str */
PyObject_GenericGetAttr, /* tp_getattro */
0, /* tp_setattro */
0, /* tp_as_buffer */
Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC, /* tp_flags */
slice_doc, /* tp_doc */
(traverseproc)slice_traverse, /* tp_traverse */
0, /* tp_clear */
slice_richcompare, /* tp_richcompare */
0, /* tp_weaklistoffset */
0, /* tp_iter */
0, /* tp_iternext */
slice_methods, /* tp_methods */
slice_members, /* 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 */
slice_new, /* tp_new */
};