cpython/Objects/rangeobject.c at master · python-emscripten/cpython · GitHub

Repository navigation

History

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

594

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

715

716

717

718

719

720

721

722

723

724

725

726

727

728

729

730

731

732

733

734

735

736

737

738

739

740

741

742

743

744

745

746

747

748

749

750

751

752

753

754

755

756

757

758

759

760

761

762

763

764

765

766

767

768

769

770

771

772

773

774

775

776

777

778

779

780

781

782

783

784

785

786

787

788

789

790

791

792

793

794

795

796

797

798

799

800

801

802

803

804

805

806

807

808

809

810

811

812

813

814

815

816

817

818

819

820

821

822

823

824

825

826

827

828

829

830

831

832

833

834

835

836

837

838

839

840

841

842

843

844

845

846

847

848

849

850

851

852

853

854

855

856

857

858

859

860

861

862

863

864

865

866

867

868

869

870

871

872

873

874

875

876

877

878

879

880

881

882

883

884

885

886

887

888

889

890

891

892

893

894

895

896

897

898

899

900

901

902

903

904

905

906

907

908

909

910

911

912

913

914

915

916

917

918

919

920

921

922

923

924

925

926

927

928

929

930

931

932

933

934

935

936

937

938

939

940

941

942

943

944

945

946

947

948

949

950

951

952

953

954

955

956

957

958

959

960

961

962

963

964

965

966

967

968

969

970

971

972

973

974

975

976

977

978

979

980

981

982

983

984

985

986

987

988

989

990

991

992

993

994

995

996

997

998

999

1000

/* Range object implementation */

#include "Python.h"

#include "pycore_abstract.h" // _PyIndex_Check()

#include "pycore_tupleobject.h"

#include "structmember.h" // PyMemberDef

/* Support objects whose length is > PY_SSIZE_T_MAX.

This could be sped up for small PyLongs if they fit in a Py_ssize_t.

This only matters on Win64. Though we could use long long which

would presumably help perf.

typedef struct {

PyObject_HEAD

PyObject *start;

PyObject *stop;

PyObject *step;

PyObject *length;

} rangeobject;

_Py_IDENTIFIER(iter);

/* Helper function for validating step. Always returns a new reference or

NULL on error.

static PyObject *

validate_step(PyObject *step)

{

/* No step specified, use a step of 1. */

if (!step)

return PyLong_FromLong(1);

step = PyNumber_Index(step);

if (step && _PyLong_Sign(step) == 0) {

PyErr_SetString(PyExc_ValueError,

"range() arg 3 must not be zero");

Py_CLEAR(step);

}

return step;

}

static PyObject *

compute_range_length(PyObject *start, PyObject *stop, PyObject *step);

static rangeobject *

make_range_object(PyTypeObject *type, PyObject *start,

PyObject *stop, PyObject *step)

{

rangeobject *obj = NULL;

PyObject *length;

length = compute_range_length(start, stop, step);

if (length == NULL) {

return NULL;

}

obj = PyObject_New(rangeobject, type);

if (obj == NULL) {

Py_DECREF(length);

return NULL;

}

obj->start = start;

obj->stop = stop;

obj->step = step;

obj->length = length;

return obj;

}

/* XXX(nnorwitz): should we error check if the user passes any empty ranges?

range(-10)

range(0, -5)

range(0, 5, -1)

static PyObject *

range_from_array(PyTypeObject *type, PyObject *const *args, Py_ssize_t num_args)

{

rangeobject *obj;

PyObject *start = NULL, *stop = NULL, *step = NULL;

switch (num_args) {

case 3:

step = args[2];

/* fallthrough */

case 2:

/* Convert borrowed refs to owned refs */

start = PyNumber_Index(args[0]);

if (!start) {

return NULL;

}

stop = PyNumber_Index(args[1]);

if (!stop) {

Py_DECREF(start);

return NULL;

}

step = validate_step(step); /* Caution, this can clear exceptions */

if (!step) {

Py_DECREF(start);

Py_DECREF(stop);

return NULL;

}

break;

case 1:

stop = PyNumber_Index(args[0]);

if (!stop) {

return NULL;

}

Py_INCREF(_PyLong_Zero);

start = _PyLong_Zero;

Py_INCREF(_PyLong_One);

step = _PyLong_One;

break;

case 0:

PyErr_SetString(PyExc_TypeError,

"range expected at least 1 argument, got 0");

return NULL;

default:

PyErr_Format(PyExc_TypeError,

"range expected at most 3 arguments, got %zd",

num_args);

return NULL;

}

obj = make_range_object(type, start, stop, step);

if (obj != NULL) {

return (PyObject *) obj;

}

/* Failed to create object, release attributes */

Py_DECREF(start);

Py_DECREF(stop);

Py_DECREF(step);

return NULL;

}

static PyObject *

range_new(PyTypeObject *type, PyObject *args, PyObject *kw)

{

if (!_PyArg_NoKeywords("range", kw))

return NULL;

return range_from_array(type, _PyTuple_ITEMS(args), PyTuple_GET_SIZE(args));

}

static PyObject *

range_vectorcall(PyTypeObject *type, PyObject *const *args,

size_t nargsf, PyObject *kwnames)

{

Py_ssize_t nargs = PyVectorcall_NARGS(nargsf);

if (!_PyArg_NoKwnames("range", kwnames)) {

return NULL;

}

return range_from_array(type, args, nargs);

}

PyDoc_STRVAR(range_doc,

"range(stop) -> range object\n\

range(start, stop[, step]) -> range object\n\

\n\

Return an object that produces a sequence of integers from start (inclusive)\n\

to stop (exclusive) by step. range(i, j) produces i, i+1, i+2, ..., j-1.\n\

start defaults to 0, and stop is omitted! range(4) produces 0, 1, 2, 3.\n\

These are exactly the valid indices for a list of 4 elements.\n\

When step is given, it specifies the increment (or decrement).");

static void

range_dealloc(rangeobject *r)

{

Py_DECREF(r->start);

Py_DECREF(r->stop);

Py_DECREF(r->step);

Py_DECREF(r->length);

PyObject_Del(r);

}

/* Return number of items in range (lo, hi, step) as a PyLong object,

* when arguments are PyLong objects. Arguments MUST return 1 with

* PyLong_Check(). Return NULL when there is an error.

static PyObject*

compute_range_length(PyObject *start, PyObject *stop, PyObject *step)

{

/* -------------------------------------------------------------

Algorithm is equal to that of get_len_of_range(), but it operates

on PyObjects (which are assumed to be PyLong objects).

---------------------------------------------------------------*/

int cmp_result;

PyObject *lo, *hi;

PyObject *diff = NULL;

PyObject *tmp1 = NULL, *tmp2 = NULL, *result;

/* holds sub-expression evaluations */

cmp_result = PyObject_RichCompareBool(step, _PyLong_Zero, Py_GT);

if (cmp_result == -1)

return NULL;

if (cmp_result == 1) {

lo = start;

hi = stop;

Py_INCREF(step);

} else {

lo = stop;

hi = start;

step = PyNumber_Negative(step);

if (!step)

return NULL;

}

/* if (lo >= hi), return length of 0. */

cmp_result = PyObject_RichCompareBool(lo, hi, Py_GE);

if (cmp_result != 0) {

Py_DECREF(step);

if (cmp_result < 0)

return NULL;

return PyLong_FromLong(0);

}

if ((tmp1 = PyNumber_Subtract(hi, lo)) == NULL)

goto Fail;

if ((diff = PyNumber_Subtract(tmp1, _PyLong_One)) == NULL)

goto Fail;

if ((tmp2 = PyNumber_FloorDivide(diff, step)) == NULL)

goto Fail;

if ((result = PyNumber_Add(tmp2, _PyLong_One)) == NULL)

goto Fail;

Py_DECREF(tmp2);

Py_DECREF(diff);

Py_DECREF(step);

Py_DECREF(tmp1);

return result;

Fail:

Py_DECREF(step);

Py_XDECREF(tmp2);

Py_XDECREF(diff);

Py_XDECREF(tmp1);

return NULL;

}

static Py_ssize_t

range_length(rangeobject *r)

{

return PyLong_AsSsize_t(r->length);

}

static PyObject *

compute_item(rangeobject *r, PyObject *i)

{

PyObject *incr, *result;

/* PyLong equivalent to:

* return r->start + (i * r->step)

incr = PyNumber_Multiply(i, r->step);

if (!incr)

return NULL;

result = PyNumber_Add(r->start, incr);

Py_DECREF(incr);

return result;

}

static PyObject *

compute_range_item(rangeobject *r, PyObject *arg)

{

int cmp_result;

PyObject *i, *result;

/* PyLong equivalent to:

* if (arg < 0) {

* i = r->length + arg

* } else {

* i = arg

* }

cmp_result = PyObject_RichCompareBool(arg, _PyLong_Zero, Py_LT);

if (cmp_result == -1) {

return NULL;

}

if (cmp_result == 1) {

i = PyNumber_Add(r->length, arg);

if (!i) {

return NULL;

}

} else {

i = arg;

Py_INCREF(i);

}

/* PyLong equivalent to:

* if (i < 0 || i >= r->length) {

* <report index out of bounds>

* }

cmp_result = PyObject_RichCompareBool(i, _PyLong_Zero, Py_LT);

if (cmp_result == 0) {

cmp_result = PyObject_RichCompareBool(i, r->length, Py_GE);

}

if (cmp_result == -1) {

Py_DECREF(i);

return NULL;

}

if (cmp_result == 1) {

Py_DECREF(i);

PyErr_SetString(PyExc_IndexError,

"range object index out of range");

return NULL;

}

result = compute_item(r, i);

Py_DECREF(i);

return result;

}

static PyObject *

range_item(rangeobject *r, Py_ssize_t i)

{

PyObject *res, *arg = PyLong_FromSsize_t(i);

if (!arg) {

return NULL;

}

res = compute_range_item(r, arg);

Py_DECREF(arg);

return res;

}

static PyObject *

compute_slice(rangeobject *r, PyObject *_slice)

{

PySliceObject *slice = (PySliceObject *) _slice;

rangeobject *result;

PyObject *start = NULL, *stop = NULL, *step = NULL;

PyObject *substart = NULL, *substop = NULL, *substep = NULL;

int error;

error = _PySlice_GetLongIndices(slice, r->length, &start, &stop, &step);

if (error == -1)

return NULL;

substep = PyNumber_Multiply(r->step, step);

if (substep == NULL) goto fail;

Py_CLEAR(step);

substart = compute_item(r, start);

if (substart == NULL) goto fail;

Py_CLEAR(start);

substop = compute_item(r, stop);

if (substop == NULL) goto fail;

Py_CLEAR(stop);

result = make_range_object(Py_TYPE(r), substart, substop, substep);

if (result != NULL) {

return (PyObject *) result;

}

fail:

Py_XDECREF(start);

Py_XDECREF(stop);

Py_XDECREF(step);

Py_XDECREF(substart);

Py_XDECREF(substop);

Py_XDECREF(substep);

return NULL;

}

/* Assumes (PyLong_CheckExact(ob) || PyBool_Check(ob)) */

static int

range_contains_long(rangeobject *r, PyObject *ob)

{

int cmp1, cmp2, cmp3;

PyObject *tmp1 = NULL;

PyObject *tmp2 = NULL;

int result = -1;

/* Check if the value can possibly be in the range. */

cmp1 = PyObject_RichCompareBool(r->step, _PyLong_Zero, Py_GT);

if (cmp1 == -1)

goto end;

if (cmp1 == 1) { /* positive steps: start <= ob < stop */

cmp2 = PyObject_RichCompareBool(r->start, ob, Py_LE);

cmp3 = PyObject_RichCompareBool(ob, r->stop, Py_LT);

}

else { /* negative steps: stop < ob <= start */

cmp2 = PyObject_RichCompareBool(ob, r->start, Py_LE);

cmp3 = PyObject_RichCompareBool(r->stop, ob, Py_LT);

}

if (cmp2 == -1 || cmp3 == -1) /* TypeError */

goto end;

if (cmp2 == 0 || cmp3 == 0) { /* ob outside of range */

result = 0;

goto end;

}

/* Check that the stride does not invalidate ob's membership. */

tmp1 = PyNumber_Subtract(ob, r->start);

if (tmp1 == NULL)

goto end;

tmp2 = PyNumber_Remainder(tmp1, r->step);

if (tmp2 == NULL)

goto end;

/* result = ((int(ob) - start) % step) == 0 */

result = PyObject_RichCompareBool(tmp2, _PyLong_Zero, Py_EQ);

end:

Py_XDECREF(tmp1);

Py_XDECREF(tmp2);

return result;

}

static int

range_contains(rangeobject *r, PyObject *ob)

{

if (PyLong_CheckExact(ob) || PyBool_Check(ob))

return range_contains_long(r, ob);

return (int)_PySequence_IterSearch((PyObject*)r, ob,

PY_ITERSEARCH_CONTAINS);

}

/* Compare two range objects. Return 1 for equal, 0 for not equal

and -1 on error. The algorithm is roughly the C equivalent of

if r0 is r1:

return True

if len(r0) != len(r1):

return False

if not len(r0):

return True

if r0.start != r1.start:

return False

if len(r0) == 1:

return True

return r0.step == r1.step

static int

range_equals(rangeobject *r0, rangeobject *r1)

{

int cmp_result;

if (r0 == r1)

return 1;

cmp_result = PyObject_RichCompareBool(r0->length, r1->length, Py_EQ);

/* Return False or error to the caller. */

if (cmp_result != 1)

return cmp_result;

cmp_result = PyObject_Not(r0->length);

/* Return True or error to the caller. */

if (cmp_result != 0)

return cmp_result;

cmp_result = PyObject_RichCompareBool(r0->start, r1->start, Py_EQ);

/* Return False or error to the caller. */

if (cmp_result != 1)

return cmp_result;

cmp_result = PyObject_RichCompareBool(r0->length, _PyLong_One, Py_EQ);

/* Return True or error to the caller. */

if (cmp_result != 0)

return cmp_result;

return PyObject_RichCompareBool(r0->step, r1->step, Py_EQ);

}

static PyObject *

range_richcompare(PyObject *self, PyObject *other, int op)

{

int result;

if (!PyRange_Check(other))

Py_RETURN_NOTIMPLEMENTED;

switch (op) {

case Py_NE:

case Py_EQ:

result = range_equals((rangeobject*)self, (rangeobject*)other);

if (result == -1)

return NULL;

if (op == Py_NE)

result = !result;

if (result)

Py_RETURN_TRUE;

else

Py_RETURN_FALSE;

case Py_LE:

case Py_GE:

case Py_LT:

case Py_GT:

Py_RETURN_NOTIMPLEMENTED;

default:

PyErr_BadArgument();

return NULL;

}

/* Hash function for range objects. Rough C equivalent of

if not len(r):

return hash((len(r), None, None))

if len(r) == 1:

return hash((len(r), r.start, None))

return hash((len(r), r.start, r.step))

static Py_hash_t

range_hash(rangeobject *r)

{

PyObject *t;

Py_hash_t result = -1;

int cmp_result;

t = PyTuple_New(3);

if (!t)

return -1;

Py_INCREF(r->length);

PyTuple_SET_ITEM(t, 0, r->length);

cmp_result = PyObject_Not(r->length);

if (cmp_result == -1)

goto end;

if (cmp_result == 1) {

Py_INCREF(Py_None);

PyTuple_SET_ITEM(t, 1, Py_None);

PyTuple_SET_ITEM(t, 2, Py_None);

}

else {

Py_INCREF(r->start);

PyTuple_SET_ITEM(t, 1, r->start);

cmp_result = PyObject_RichCompareBool(r->length, _PyLong_One, Py_EQ);

if (cmp_result == -1)

goto end;

if (cmp_result == 1) {

Py_INCREF(Py_None);

PyTuple_SET_ITEM(t, 2, Py_None);

}

else {

Py_INCREF(r->step);

PyTuple_SET_ITEM(t, 2, r->step);

}

result = PyObject_Hash(t);

end:

Py_DECREF(t);

return result;

}

static PyObject *

range_count(rangeobject *r, PyObject *ob)

{

if (PyLong_CheckExact(ob) || PyBool_Check(ob)) {

int result = range_contains_long(r, ob);

if (result == -1)

return NULL;

return PyLong_FromLong(result);

} else {

Py_ssize_t count;

count = _PySequence_IterSearch((PyObject*)r, ob, PY_ITERSEARCH_COUNT);

if (count == -1)

return NULL;

return PyLong_FromSsize_t(count);

}

static PyObject *

range_index(rangeobject *r, PyObject *ob)

{

int contains;

if (!PyLong_CheckExact(ob) && !PyBool_Check(ob)) {

Py_ssize_t index;

index = _PySequence_IterSearch((PyObject*)r, ob, PY_ITERSEARCH_INDEX);

if (index == -1)

return NULL;

return PyLong_FromSsize_t(index);

}

contains = range_contains_long(r, ob);

if (contains == -1)

return NULL;

if (contains) {

PyObject *idx, *tmp = PyNumber_Subtract(ob, r->start);

if (tmp == NULL)

return NULL;

/* idx = (ob - r.start) // r.step */

idx = PyNumber_FloorDivide(tmp, r->step);

Py_DECREF(tmp);

return idx;

}

/* object is not in the range */

PyErr_Format(PyExc_ValueError, "%R is not in range", ob);

return NULL;

}

static PySequenceMethods range_as_sequence = {

(lenfunc)range_length, /* sq_length */

0, /* sq_concat */

0, /* sq_repeat */

(ssizeargfunc)range_item, /* sq_item */

0, /* sq_slice */

0, /* sq_ass_item */

0, /* sq_ass_slice */

(objobjproc)range_contains, /* sq_contains */

};

static PyObject *

range_repr(rangeobject *r)

{

Py_ssize_t istep;

/* Check for special case values for printing. We don't always

need the step value. We don't care about overflow. */

istep = PyNumber_AsSsize_t(r->step, NULL);

if (istep == -1 && PyErr_Occurred()) {

assert(!PyErr_ExceptionMatches(PyExc_OverflowError));

return NULL;

}

if (istep == 1)

return PyUnicode_FromFormat("range(%R, %R)", r->start, r->stop);

else

return PyUnicode_FromFormat("range(%R, %R, %R)",

r->start, r->stop, r->step);

}

/* Pickling support */

static PyObject *

range_reduce(rangeobject *r, PyObject *args)

{

return Py_BuildValue("(O(OOO))", Py_TYPE(r),

r->start, r->stop, r->step);

}

static PyObject *

range_subscript(rangeobject* self, PyObject* item)

{

if (_PyIndex_Check(item)) {

PyObject *i, *result;

i = PyNumber_Index(item);

if (!i)

return NULL;

result = compute_range_item(self, i);

Py_DECREF(i);

return result;

}

if (PySlice_Check(item)) {

return compute_slice(self, item);

}

PyErr_Format(PyExc_TypeError,

"range indices must be integers or slices, not %.200s",

Py_TYPE(item)->tp_name);

return NULL;

}

static PyMappingMethods range_as_mapping = {

(lenfunc)range_length, /* mp_length */

(binaryfunc)range_subscript, /* mp_subscript */

(objobjargproc)0, /* mp_ass_subscript */

};

static int

range_bool(rangeobject* self)

{

return PyObject_IsTrue(self->length);

}

static PyNumberMethods range_as_number = {

.nb_bool = (inquiry)range_bool,

};

static PyObject * range_iter(PyObject *seq);

static PyObject * range_reverse(PyObject *seq, PyObject *Py_UNUSED(ignored));

PyDoc_STRVAR(reverse_doc,

"Return a reverse iterator.");

PyDoc_STRVAR(count_doc,

"rangeobject.count(value) -> integer -- return number of occurrences of value");

PyDoc_STRVAR(index_doc,

"rangeobject.index(value) -> integer -- return index of value.\n"

"Raise ValueError if the value is not present.");

static PyMethodDef range_methods[] = {

{"__reversed__", range_reverse, METH_NOARGS, reverse_doc},

{"__reduce__", (PyCFunction)range_reduce, METH_VARARGS},

{"count", (PyCFunction)range_count, METH_O, count_doc},

{"index", (PyCFunction)range_index, METH_O, index_doc},

{NULL, NULL} /* sentinel */

};

static PyMemberDef range_members[] = {

{"start", T_OBJECT_EX, offsetof(rangeobject, start), READONLY},

{"stop", T_OBJECT_EX, offsetof(rangeobject, stop), READONLY},

{"step", T_OBJECT_EX, offsetof(rangeobject, step), READONLY},

{0}

};

PyTypeObject PyRange_Type = {

PyVarObject_HEAD_INIT(&PyType_Type, 0)

"range", /* Name of this type */

sizeof(rangeobject), /* Basic object size */

0, /* Item size for varobject */

(destructor)range_dealloc, /* tp_dealloc */

0, /* tp_vectorcall_offset */

0, /* tp_getattr */

0, /* tp_setattr */

0, /* tp_as_async */

(reprfunc)range_repr, /* tp_repr */

&range_as_number, /* tp_as_number */

&range_as_sequence, /* tp_as_sequence */

&range_as_mapping, /* tp_as_mapping */

(hashfunc)range_hash, /* 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 */

range_richcompare, /* tp_richcompare */

0, /* tp_weaklistoffset */

range_iter, /* tp_iter */

0, /* tp_iternext */

range_methods, /* tp_methods */

range_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 */

range_new, /* tp_new */

.tp_vectorcall = (vectorcallfunc)range_vectorcall

};

/*********************** range Iterator **************************/

/* There are 2 types of iterators, one for C longs, the other for

Python ints (ie, PyObjects). This should make iteration fast

in the normal case, but possible for any numeric value.

typedef struct {

PyObject_HEAD

long index;

long start;

long step;

long len;

} rangeiterobject;

static PyObject *

rangeiter_next(rangeiterobject *r)

{

if (r->index < r->len)

/* cast to unsigned to avoid possible signed overflow

in intermediate calculations. */

return PyLong_FromLong((long)(r->start +

(unsigned long)(r->index++) * r->step));

return NULL;

}

static PyObject *

rangeiter_len(rangeiterobject *r, PyObject *Py_UNUSED(ignored))

{

return PyLong_FromLong(r->len - r->index);

}

PyDoc_STRVAR(length_hint_doc,

"Private method returning an estimate of len(list(it)).");

static PyObject *

rangeiter_reduce(rangeiterobject *r, PyObject *Py_UNUSED(ignored))

{

PyObject *start=NULL, *stop=NULL, *step=NULL;

PyObject *range;

/* create a range object for pickling */

start = PyLong_FromLong(r->start);

if (start == NULL)

goto err;

stop = PyLong_FromLong(r->start + r->len * r->step);

if (stop == NULL)

goto err;

step = PyLong_FromLong(r->step);

if (step == NULL)

goto err;

range = (PyObject*)make_range_object(&PyRange_Type,

start, stop, step);

if (range == NULL)

goto err;

/* return the result */

return Py_BuildValue("N(N)i", _PyEval_GetBuiltinId(&PyId_iter),

range, r->index);

err:

Py_XDECREF(start);

Py_XDECREF(stop);

Py_XDECREF(step);

return NULL;

}

static PyObject *

rangeiter_setstate(rangeiterobject *r, PyObject *state)

{

long index = PyLong_AsLong(state);

if (index == -1 && PyErr_Occurred())

return NULL;

/* silently clip the index value */

if (index < 0)

index = 0;

else if (index > r->len)

index = r->len; /* exhausted iterator */

r->index = index;

Py_RETURN_NONE;

}

PyDoc_STRVAR(reduce_doc, "Return state information for pickling.");

PyDoc_STRVAR(setstate_doc, "Set state information for unpickling.");

static PyMethodDef rangeiter_methods[] = {

{"__length_hint__", (PyCFunction)rangeiter_len, METH_NOARGS,

length_hint_doc},

{"__reduce__", (PyCFunction)rangeiter_reduce, METH_NOARGS,

reduce_doc},

{"__setstate__", (PyCFunction)rangeiter_setstate, METH_O,

setstate_doc},

{NULL, NULL} /* sentinel */

};

PyTypeObject PyRangeIter_Type = {

PyVarObject_HEAD_INIT(&PyType_Type, 0)

"range_iterator", /* tp_name */

sizeof(rangeiterobject), /* tp_basicsize */

0, /* tp_itemsize */

/* methods */

(destructor)PyObject_Del, /* tp_dealloc */

0, /* tp_vectorcall_offset */

0, /* tp_getattr */

0, /* tp_setattr */

0, /* tp_as_async */

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 */

PyObject_SelfIter, /* tp_iter */

(iternextfunc)rangeiter_next, /* tp_iternext */

rangeiter_methods, /* tp_methods */

0, /* tp_members */

};

/* Return number of items in range (lo, hi, step). step != 0

* required. The result always fits in an unsigned long.

static unsigned long

get_len_of_range(long lo, long hi, long step)

{

/* -------------------------------------------------------------

If step > 0 and lo >= hi, or step < 0 and lo <= hi, the range is empty.

Else for step > 0, 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. The analysis for step < 0

is similar.

---------------------------------------------------------------*/

assert(step != 0);

if (step > 0 && lo < hi)

return 1UL + (hi - 1UL - lo) / step;

else if (step < 0 && lo > hi)

return 1UL + (lo - 1UL - hi) / (0UL - step);

else

return 0UL;

}

/* Initialize a rangeiter object. If the length of the rangeiter object

is not representable as a C long, OverflowError is raised. */

static PyObject *

fast_range_iter(long start, long stop, long step)

{

rangeiterobject *it = PyObject_New(rangeiterobject, &PyRangeIter_Type);

unsigned long ulen;

if (it == NULL)

return NULL;

it->start = start;

it->step = step;

ulen = get_len_of_range(start, stop, step);

if (ulen > (unsigned long)LONG_MAX) {

Py_DECREF(it);

PyErr_SetString(PyExc_OverflowError,

"range too large to represent as a range_iterator");

return NULL;

}

it->len = (long)ulen;

it->index = 0;

return (PyObject *)it;

}

typedef struct {

PyObject_HEAD

PyObject *index;

PyObject *start;

PyObject *step;

PyObject *len;

} longrangeiterobject;

static PyObject *

longrangeiter_len(longrangeiterobject *r, PyObject *no_args)

{

return PyNumber_Subtract(r->len, r->index);

}

static PyObject *

longrangeiter_reduce(longrangeiterobject *r, PyObject *Py_UNUSED(ignored))

{

PyObject *product, *stop=NULL;

PyObject *range;

/* create a range object for pickling. Must calculate the "stop" value */

product = PyNumber_Multiply(r->len, r->step);

if (product == NULL)

return NULL;

stop = PyNumber_Add(r->start, product);

Py_DECREF(product);

if (stop == NULL)

return NULL;

Py_INCREF(r->start);

Py_INCREF(r->step);

range = (PyObject*)make_range_object(&PyRange_Type,

r->start, stop, r->step);

if (range == NULL) {

Py_DECREF(r->start);

Py_DECREF(stop);

Py_DECREF(r->step);

return NULL;

}

/* return the result */

return Py_BuildValue("N(N)O", _PyEval_GetBuiltinId(&PyId_iter),

range, r->index);

}

static PyObject *

longrangeiter_setstate(longrangeiterobject *r, PyObject *state)

{

int cmp;

/* clip the value */

cmp = PyObject_RichCompareBool(state, _PyLong_Zero, Py_LT);

if (cmp < 0)

return NULL;

if (cmp > 0) {

state = _PyLong_Zero;

}

else {

cmp = PyObject_RichCompareBool(r->len, state, Py_LT);

if (cmp < 0)

return NULL;

if (cmp > 0)

state = r->len;

}

Py_INCREF(state);

Py_XSETREF(r->index, state);

Py_RETURN_NONE;

}

static PyMethodDef longrangeiter_methods[] = {

{"__length_hint__", (PyCFunction)longrangeiter_len, METH_NOARGS,

length_hint_doc},

{"__reduce__", (PyCFunction)longrangeiter_reduce, METH_NOARGS,

reduce_doc},

{"__setstate__", (PyCFunction)longrangeiter_setstate, METH_O,

setstate_doc},

{NULL, NULL} /* sentinel */

};

static void

longrangeiter_dealloc(longrangeiterobject *r)

{

Py_XDECREF(r->index);

Py_XDECREF(r->start);

View remainder of file in raw view

cpython/Objects/rangeobject.c at master · python-emscripten/cpython · GitHub

Repository navigation

Expand file tree

Breadcrumbs

rangeobject.c

Latest commit

History

Breadcrumbs

rangeobject.c

File metadata and controls