cpython/Objects/listobject.c at 3.5 · python/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

/* List object implementation */

#include "Python.h"

#include "accu.h"

#ifdef STDC_HEADERS

#include <stddef.h>

#else

#include <sys/types.h> /* For size_t */

#endif

/* Ensure ob_item has room for at least newsize elements, and set

* ob_size to newsize. If newsize > ob_size on entry, the content

* of the new slots at exit is undefined heap trash; it's the caller's

* responsibility to overwrite them with sane values.

* The number of allocated elements may grow, shrink, or stay the same.

* Failure is impossible if newsize <= self.allocated on entry, although

* that partly relies on an assumption that the system realloc() never

* fails when passed a number of bytes <= the number of bytes last

* allocated (the C standard doesn't guarantee this, but it's hard to

* imagine a realloc implementation where it wouldn't be true).

* Note that self->ob_item may change, and even if newsize is less

* than ob_size on entry.

static int

list_resize(PyListObject *self, Py_ssize_t newsize)

{

PyObject **items;

size_t new_allocated;

Py_ssize_t allocated = self->allocated;

/* Bypass realloc() when a previous overallocation is large enough

to accommodate the newsize. If the newsize falls lower than half

the allocated size, then proceed with the realloc() to shrink the list.

if (allocated >= newsize && newsize >= (allocated >> 1)) {

assert(self->ob_item != NULL || newsize == 0);

Py_SIZE(self) = newsize;

return 0;

}

/* This over-allocates proportional to the list size, making room

* for additional growth. The over-allocation is mild, but is

* enough to give linear-time amortized behavior over a long

* sequence of appends() in the presence of a poorly-performing

* system realloc().

* The growth pattern is: 0, 4, 8, 16, 25, 35, 46, 58, 72, 88, ...

new_allocated = (newsize >> 3) + (newsize < 9 ? 3 : 6);

/* check for integer overflow */

if (new_allocated > PY_SIZE_MAX - newsize) {

PyErr_NoMemory();

return -1;

} else {

new_allocated += newsize;

}

if (newsize == 0)

new_allocated = 0;

items = self->ob_item;

if (new_allocated <= (PY_SIZE_MAX / sizeof(PyObject *)))

PyMem_RESIZE(items, PyObject *, new_allocated);

else

items = NULL;

if (items == NULL) {

PyErr_NoMemory();

return -1;

}

self->ob_item = items;

Py_SIZE(self) = newsize;

self->allocated = new_allocated;

return 0;

}

/* Debug statistic to compare allocations with reuse through the free list */

#undef SHOW_ALLOC_COUNT

#ifdef SHOW_ALLOC_COUNT

static size_t count_alloc = 0;

static size_t count_reuse = 0;

static void

show_alloc(void)

{

fprintf(stderr, "List allocations: %" PY_FORMAT_SIZE_T "d\n",

count_alloc);

fprintf(stderr, "List reuse through freelist: %" PY_FORMAT_SIZE_T

"d\n", count_reuse);

fprintf(stderr, "%.2f%% reuse rate\n\n",

(100.0*count_reuse/(count_alloc+count_reuse)));

}

#endif

/* Empty list reuse scheme to save calls to malloc and free */

#ifndef PyList_MAXFREELIST

#define PyList_MAXFREELIST 80

#endif

static PyListObject *free_list[PyList_MAXFREELIST];

static int numfree = 0;

int

PyList_ClearFreeList(void)

{

PyListObject *op;

int ret = numfree;

while (numfree) {

op = free_list[--numfree];

assert(PyList_CheckExact(op));

PyObject_GC_Del(op);

}

return ret;

}

void

PyList_Fini(void)

{

PyList_ClearFreeList();

}

/* Print summary info about the state of the optimized allocator */

void

_PyList_DebugMallocStats(FILE *out)

{

_PyDebugAllocatorStats(out,

"free PyListObject",

numfree, sizeof(PyListObject));

}

PyObject *

PyList_New(Py_ssize_t size)

{

PyListObject *op;

size_t nbytes;

#ifdef SHOW_ALLOC_COUNT

static int initialized = 0;

if (!initialized) {

Py_AtExit(show_alloc);

initialized = 1;

}

#endif

if (size < 0) {

PyErr_BadInternalCall();

return NULL;

}

/* Check for overflow without an actual overflow,

* which can cause compiler to optimise out */

if ((size_t)size > PY_SIZE_MAX / sizeof(PyObject *))

return PyErr_NoMemory();

nbytes = size * sizeof(PyObject *);

if (numfree) {

numfree--;

op = free_list[numfree];

_Py_NewReference((PyObject *)op);

#ifdef SHOW_ALLOC_COUNT

count_reuse++;

#endif

} else {

op = PyObject_GC_New(PyListObject, &PyList_Type);

if (op == NULL)

return NULL;

#ifdef SHOW_ALLOC_COUNT

count_alloc++;

#endif

}

if (size <= 0)

op->ob_item = NULL;

else {

op->ob_item = (PyObject **) PyMem_MALLOC(nbytes);

if (op->ob_item == NULL) {

Py_DECREF(op);

return PyErr_NoMemory();

}

memset(op->ob_item, 0, nbytes);

}

Py_SIZE(op) = size;

op->allocated = size;

_PyObject_GC_TRACK(op);

return (PyObject *) op;

}

Py_ssize_t

PyList_Size(PyObject *op)

{

if (!PyList_Check(op)) {

PyErr_BadInternalCall();

return -1;

}

else

return Py_SIZE(op);

}

static PyObject *indexerr = NULL;

PyObject *

PyList_GetItem(PyObject *op, Py_ssize_t i)

{

if (!PyList_Check(op)) {

PyErr_BadInternalCall();

return NULL;

}

if (i < 0 || i >= Py_SIZE(op)) {

if (indexerr == NULL) {

indexerr = PyUnicode_FromString(

"list index out of range");

if (indexerr == NULL)

return NULL;

}

PyErr_SetObject(PyExc_IndexError, indexerr);

return NULL;

}

return ((PyListObject *)op) -> ob_item[i];

}

int

PyList_SetItem(PyObject *op, Py_ssize_t i,

PyObject *newitem)

{

PyObject *olditem;

PyObject **p;

if (!PyList_Check(op)) {

Py_XDECREF(newitem);

PyErr_BadInternalCall();

return -1;

}

if (i < 0 || i >= Py_SIZE(op)) {

Py_XDECREF(newitem);

PyErr_SetString(PyExc_IndexError,

"list assignment index out of range");

return -1;

}

p = ((PyListObject *)op) -> ob_item + i;

olditem = *p;

*p = newitem;

Py_XDECREF(olditem);

return 0;

}

static int

ins1(PyListObject *self, Py_ssize_t where, PyObject *v)

{

Py_ssize_t i, n = Py_SIZE(self);

PyObject **items;

if (v == NULL) {

PyErr_BadInternalCall();

return -1;

}

if (n == PY_SSIZE_T_MAX) {

PyErr_SetString(PyExc_OverflowError,

"cannot add more objects to list");

return -1;

}

if (list_resize(self, n+1) == -1)

return -1;

if (where < 0) {

where += n;

if (where < 0)

where = 0;

}

if (where > n)

where = n;

items = self->ob_item;

for (i = n; --i >= where; )

items[i+1] = items[i];

Py_INCREF(v);

items[where] = v;

return 0;

}

int

PyList_Insert(PyObject *op, Py_ssize_t where, PyObject *newitem)

{

if (!PyList_Check(op)) {

PyErr_BadInternalCall();

return -1;

}

return ins1((PyListObject *)op, where, newitem);

}

static int

app1(PyListObject *self, PyObject *v)

{

Py_ssize_t n = PyList_GET_SIZE(self);

assert (v != NULL);

if (n == PY_SSIZE_T_MAX) {

PyErr_SetString(PyExc_OverflowError,

"cannot add more objects to list");

return -1;

}

if (list_resize(self, n+1) == -1)

return -1;

Py_INCREF(v);

PyList_SET_ITEM(self, n, v);

return 0;

}

int

PyList_Append(PyObject *op, PyObject *newitem)

{

if (PyList_Check(op) && (newitem != NULL))

return app1((PyListObject *)op, newitem);

PyErr_BadInternalCall();

return -1;

}

/* Methods */

static void

list_dealloc(PyListObject *op)

{

Py_ssize_t i;

PyObject_GC_UnTrack(op);

Py_TRASHCAN_SAFE_BEGIN(op)

if (op->ob_item != NULL) {

/* Do it backwards, for Christian Tismer.

There's a simple test case where somehow this reduces

thrashing when a *very* large list is created and

immediately deleted. */

i = Py_SIZE(op);

while (--i >= 0) {

Py_XDECREF(op->ob_item[i]);

}

PyMem_FREE(op->ob_item);

}

if (numfree < PyList_MAXFREELIST && PyList_CheckExact(op))

free_list[numfree++] = op;

else

Py_TYPE(op)->tp_free((PyObject *)op);

Py_TRASHCAN_SAFE_END(op)

}

static PyObject *

list_repr(PyListObject *v)

{

Py_ssize_t i;

PyObject *s;

_PyUnicodeWriter writer;

if (Py_SIZE(v) == 0) {

return PyUnicode_FromString("[]");

}

i = Py_ReprEnter((PyObject*)v);

if (i != 0) {

return i > 0 ? PyUnicode_FromString("[...]") : NULL;

}

_PyUnicodeWriter_Init(&writer);

writer.overallocate = 1;

/* "[" + "1" + ", 2" * (len - 1) + "]" */

writer.min_length = 1 + 1 + (2 + 1) * (Py_SIZE(v) - 1) + 1;

if (_PyUnicodeWriter_WriteChar(&writer, '[') < 0)

goto error;

/* Do repr() on each element. Note that this may mutate the list,

so must refetch the list size on each iteration. */

for (i = 0; i < Py_SIZE(v); ++i) {

if (i > 0) {

if (_PyUnicodeWriter_WriteASCIIString(&writer, ", ", 2) < 0)

goto error;

}

if (Py_EnterRecursiveCall(" while getting the repr of a list"))

goto error;

s = PyObject_Repr(v->ob_item[i]);

Py_LeaveRecursiveCall();

if (s == NULL)

goto error;

if (_PyUnicodeWriter_WriteStr(&writer, s) < 0) {

Py_DECREF(s);

goto error;

}

Py_DECREF(s);

}

writer.overallocate = 0;

if (_PyUnicodeWriter_WriteChar(&writer, ']') < 0)

goto error;

Py_ReprLeave((PyObject *)v);

return _PyUnicodeWriter_Finish(&writer);

error:

_PyUnicodeWriter_Dealloc(&writer);

Py_ReprLeave((PyObject *)v);

return NULL;

}

static Py_ssize_t

list_length(PyListObject *a)

{

return Py_SIZE(a);

}

static int

list_contains(PyListObject *a, PyObject *el)

{

Py_ssize_t i;

int cmp;

for (i = 0, cmp = 0 ; cmp == 0 && i < Py_SIZE(a); ++i)

cmp = PyObject_RichCompareBool(el, PyList_GET_ITEM(a, i),

Py_EQ);

return cmp;

}

static PyObject *

list_item(PyListObject *a, Py_ssize_t i)

{

if (i < 0 || i >= Py_SIZE(a)) {

if (indexerr == NULL) {

indexerr = PyUnicode_FromString(

"list index out of range");

if (indexerr == NULL)

return NULL;

}

PyErr_SetObject(PyExc_IndexError, indexerr);

return NULL;

}

Py_INCREF(a->ob_item[i]);

return a->ob_item[i];

}

static PyObject *

list_slice(PyListObject *a, Py_ssize_t ilow, Py_ssize_t ihigh)

{

PyListObject *np;

PyObject **src, **dest;

Py_ssize_t i, len;

if (ilow < 0)

ilow = 0;

else if (ilow > Py_SIZE(a))

ilow = Py_SIZE(a);

if (ihigh < ilow)

ihigh = ilow;

else if (ihigh > Py_SIZE(a))

ihigh = Py_SIZE(a);

len = ihigh - ilow;

np = (PyListObject *) PyList_New(len);

if (np == NULL)

return NULL;

src = a->ob_item + ilow;

dest = np->ob_item;

for (i = 0; i < len; i++) {

PyObject *v = src[i];

Py_INCREF(v);

dest[i] = v;

}

return (PyObject *)np;

}

PyObject *

PyList_GetSlice(PyObject *a, Py_ssize_t ilow, Py_ssize_t ihigh)

{

if (!PyList_Check(a)) {

PyErr_BadInternalCall();

return NULL;

}

return list_slice((PyListObject *)a, ilow, ihigh);

}

static PyObject *

list_concat(PyListObject *a, PyObject *bb)

{

Py_ssize_t size;

Py_ssize_t i;

PyObject **src, **dest;

PyListObject *np;

if (!PyList_Check(bb)) {

PyErr_Format(PyExc_TypeError,

"can only concatenate list (not \"%.200s\") to list",

bb->ob_type->tp_name);

return NULL;

}

#define b ((PyListObject *)bb)

size = Py_SIZE(a) + Py_SIZE(b);

if (size < 0)

return PyErr_NoMemory();

np = (PyListObject *) PyList_New(size);

if (np == NULL) {

return NULL;

}

src = a->ob_item;

dest = np->ob_item;

for (i = 0; i < Py_SIZE(a); i++) {

PyObject *v = src[i];

Py_INCREF(v);

dest[i] = v;

}

src = b->ob_item;

dest = np->ob_item + Py_SIZE(a);

for (i = 0; i < Py_SIZE(b); i++) {

PyObject *v = src[i];

Py_INCREF(v);

dest[i] = v;

}

return (PyObject *)np;

#undef b

}

static PyObject *

list_repeat(PyListObject *a, Py_ssize_t n)

{

Py_ssize_t i, j;

Py_ssize_t size;

PyListObject *np;

PyObject **p, **items;

PyObject *elem;

if (n < 0)

n = 0;

if (n > 0 && Py_SIZE(a) > PY_SSIZE_T_MAX / n)

return PyErr_NoMemory();

size = Py_SIZE(a) * n;

if (size == 0)

return PyList_New(0);

np = (PyListObject *) PyList_New(size);

if (np == NULL)

return NULL;

items = np->ob_item;

if (Py_SIZE(a) == 1) {

elem = a->ob_item[0];

for (i = 0; i < n; i++) {

items[i] = elem;

Py_INCREF(elem);

}

return (PyObject *) np;

}

p = np->ob_item;

items = a->ob_item;

for (i = 0; i < n; i++) {

for (j = 0; j < Py_SIZE(a); j++) {

*p = items[j];

Py_INCREF(*p);

p++;

}

return (PyObject *) np;

}

static int

list_clear(PyListObject *a)

{

Py_ssize_t i;

PyObject **item = a->ob_item;

if (item != NULL) {

/* Because XDECREF can recursively invoke operations on

this list, we make it empty first. */

i = Py_SIZE(a);

Py_SIZE(a) = 0;

a->ob_item = NULL;

a->allocated = 0;

while (--i >= 0) {

Py_XDECREF(item[i]);

}

PyMem_FREE(item);

}

/* Never fails; the return value can be ignored.

Note that there is no guarantee that the list is actually empty

at this point, because XDECREF may have populated it again! */

return 0;

}

/* a[ilow:ihigh] = v if v != NULL.

* del a[ilow:ihigh] if v == NULL.

* Special speed gimmick: when v is NULL and ihigh - ilow <= 8, it's

* guaranteed the call cannot fail.

static int

list_ass_slice(PyListObject *a, Py_ssize_t ilow, Py_ssize_t ihigh, PyObject *v)

{

/* Because [X]DECREF can recursively invoke list operations on

this list, we must postpone all [X]DECREF activity until

after the list is back in its canonical shape. Therefore

we must allocate an additional array, 'recycle', into which

we temporarily copy the items that are deleted from the

list. :-( */

PyObject *recycle_on_stack[8];

PyObject **recycle = recycle_on_stack; /* will allocate more if needed */

PyObject **item;

PyObject **vitem = NULL;

PyObject *v_as_SF = NULL; /* PySequence_Fast(v) */

Py_ssize_t n; /* # of elements in replacement list */

Py_ssize_t norig; /* # of elements in list getting replaced */

Py_ssize_t d; /* Change in size */

Py_ssize_t k;

size_t s;

int result = -1; /* guilty until proved innocent */

#define b ((PyListObject *)v)

if (v == NULL)

n = 0;

else {

if (a == b) {

/* Special case "a[i:j] = a" -- copy b first */

v = list_slice(b, 0, Py_SIZE(b));

if (v == NULL)

return result;

result = list_ass_slice(a, ilow, ihigh, v);

Py_DECREF(v);

return result;

}

v_as_SF = PySequence_Fast(v, "can only assign an iterable");

if(v_as_SF == NULL)

goto Error;

n = PySequence_Fast_GET_SIZE(v_as_SF);

vitem = PySequence_Fast_ITEMS(v_as_SF);

}

if (ilow < 0)

ilow = 0;

else if (ilow > Py_SIZE(a))

ilow = Py_SIZE(a);

if (ihigh < ilow)

ihigh = ilow;

else if (ihigh > Py_SIZE(a))

ihigh = Py_SIZE(a);

norig = ihigh - ilow;

assert(norig >= 0);

d = n - norig;

if (Py_SIZE(a) + d == 0) {

Py_XDECREF(v_as_SF);

return list_clear(a);

}

item = a->ob_item;

/* recycle the items that we are about to remove */

s = norig * sizeof(PyObject *);

/* If norig == 0, item might be NULL, in which case we may not memcpy from it. */

if (s) {

if (s > sizeof(recycle_on_stack)) {

recycle = (PyObject **)PyMem_MALLOC(s);

if (recycle == NULL) {

PyErr_NoMemory();

goto Error;

}

memcpy(recycle, &item[ilow], s);

}

if (d < 0) { /* Delete -d items */

Py_ssize_t tail;

tail = (Py_SIZE(a) - ihigh) * sizeof(PyObject *);

memmove(&item[ihigh+d], &item[ihigh], tail);

if (list_resize(a, Py_SIZE(a) + d) < 0) {

memmove(&item[ihigh], &item[ihigh+d], tail);

memcpy(&item[ilow], recycle, s);

goto Error;

}

item = a->ob_item;

}

else if (d > 0) { /* Insert d items */

k = Py_SIZE(a);

if (list_resize(a, k+d) < 0)

goto Error;

item = a->ob_item;

memmove(&item[ihigh+d], &item[ihigh],

(k - ihigh)*sizeof(PyObject *));

}

for (k = 0; k < n; k++, ilow++) {

PyObject *w = vitem[k];

Py_XINCREF(w);

item[ilow] = w;

}

for (k = norig - 1; k >= 0; --k)

Py_XDECREF(recycle[k]);

result = 0;

Error:

if (recycle != recycle_on_stack)

PyMem_FREE(recycle);

Py_XDECREF(v_as_SF);

return result;

#undef b

}

int

PyList_SetSlice(PyObject *a, Py_ssize_t ilow, Py_ssize_t ihigh, PyObject *v)

{

if (!PyList_Check(a)) {

PyErr_BadInternalCall();

return -1;

}

return list_ass_slice((PyListObject *)a, ilow, ihigh, v);

}

static PyObject *

list_inplace_repeat(PyListObject *self, Py_ssize_t n)

{

PyObject **items;

Py_ssize_t size, i, j, p;

size = PyList_GET_SIZE(self);

if (size == 0 || n == 1) {

Py_INCREF(self);

return (PyObject *)self;

}

if (n < 1) {

(void)list_clear(self);

Py_INCREF(self);

return (PyObject *)self;

}

if (size > PY_SSIZE_T_MAX / n) {

return PyErr_NoMemory();

}

if (list_resize(self, size*n) == -1)

return NULL;

p = size;

items = self->ob_item;

for (i = 1; i < n; i++) { /* Start counting at 1, not 0 */

for (j = 0; j < size; j++) {

PyObject *o = items[j];

Py_INCREF(o);

items[p++] = o;

}

Py_INCREF(self);

return (PyObject *)self;

}

static int

list_ass_item(PyListObject *a, Py_ssize_t i, PyObject *v)

{

PyObject *old_value;

if (i < 0 || i >= Py_SIZE(a)) {

PyErr_SetString(PyExc_IndexError,

"list assignment index out of range");

return -1;

}

if (v == NULL)

return list_ass_slice(a, i, i+1, v);

Py_INCREF(v);

old_value = a->ob_item[i];

a->ob_item[i] = v;

Py_DECREF(old_value);

return 0;

}

static PyObject *

listinsert(PyListObject *self, PyObject *args)

{

Py_ssize_t i;

PyObject *v;

if (!PyArg_ParseTuple(args, "nO:insert", &i, &v))

return NULL;

if (ins1(self, i, v) == 0)

Py_RETURN_NONE;

return NULL;

}

static PyObject *

listclear(PyListObject *self)

{

list_clear(self);

Py_RETURN_NONE;

}

static PyObject *

listcopy(PyListObject *self)

{

return list_slice(self, 0, Py_SIZE(self));

}

static PyObject *

listappend(PyListObject *self, PyObject *v)

{

if (app1(self, v) == 0)

Py_RETURN_NONE;

return NULL;

}

static PyObject *

listextend(PyListObject *self, PyObject *b)

{

PyObject *it; /* iter(v) */

Py_ssize_t m; /* size of self */

Py_ssize_t n; /* guess for size of b */

Py_ssize_t mn; /* m + n */

Py_ssize_t i;

PyObject *(*iternext)(PyObject *);

/* Special cases:

1) lists and tuples which can use PySequence_Fast ops

2) extending self to self requires making a copy first

if (PyList_CheckExact(b) || PyTuple_CheckExact(b) || (PyObject *)self == b) {

PyObject **src, **dest;

b = PySequence_Fast(b, "argument must be iterable");

if (!b)

return NULL;

n = PySequence_Fast_GET_SIZE(b);

if (n == 0) {

/* short circuit when b is empty */

Py_DECREF(b);

Py_RETURN_NONE;

}

m = Py_SIZE(self);

if (list_resize(self, m + n) == -1) {

Py_DECREF(b);

return NULL;

}

/* note that we may still have self == b here for the

* situation a.extend(a), but the following code works

* in that case too. Just make sure to resize self

* before calling PySequence_Fast_ITEMS.

/* populate the end of self with b's items */

src = PySequence_Fast_ITEMS(b);

dest = self->ob_item + m;

for (i = 0; i < n; i++) {

PyObject *o = src[i];

Py_INCREF(o);

dest[i] = o;

}

Py_DECREF(b);

Py_RETURN_NONE;

}

it = PyObject_GetIter(b);

if (it == NULL)

return NULL;

iternext = *it->ob_type->tp_iternext;

/* Guess a result list size. */

n = PyObject_LengthHint(b, 8);

if (n == -1) {

Py_DECREF(it);

return NULL;

}

m = Py_SIZE(self);

mn = m + n;

if (mn >= m) {

/* Make room. */

if (list_resize(self, mn) == -1)

goto error;

/* Make the list sane again. */

Py_SIZE(self) = m;

}

/* Else m + n overflowed; on the chance that n lied, and there really

* is enough room, ignore it. If n was telling the truth, we'll

* eventually run out of memory during the loop.

/* Run iterator to exhaustion. */

for (;;) {

PyObject *item = iternext(it);

if (item == NULL) {

if (PyErr_Occurred()) {

if (PyErr_ExceptionMatches(PyExc_StopIteration))

PyErr_Clear();

else

goto error;

}

break;

}

if (Py_SIZE(self) < self->allocated) {

/* steals ref */

PyList_SET_ITEM(self, Py_SIZE(self), item);

++Py_SIZE(self);

}

else {

int status = app1(self, item);

Py_DECREF(item); /* append creates a new ref */

if (status < 0)

goto error;

}

/* Cut back result list if initial guess was too large. */

if (Py_SIZE(self) < self->allocated) {

if (list_resize(self, Py_SIZE(self)) < 0)

goto error;

}

Py_DECREF(it);

Py_RETURN_NONE;

error:

Py_DECREF(it);

return NULL;

}

PyObject *

_PyList_Extend(PyListObject *self, PyObject *b)

{

return listextend(self, b);

}

static PyObject *

list_inplace_concat(PyListObject *self, PyObject *other)

{

PyObject *result;

result = listextend(self, other);

if (result == NULL)

return result;

Py_DECREF(result);

Py_INCREF(self);

return (PyObject *)self;

}

static PyObject *

listpop(PyListObject *self, PyObject *args)

{

Py_ssize_t i = -1;

PyObject *v;

int status;

if (!PyArg_ParseTuple(args, "|n:pop", &i))

return NULL;

if (Py_SIZE(self) == 0) {

/* Special-case most common failure cause */

PyErr_SetString(PyExc_IndexError, "pop from empty list");

return NULL;

}

if (i < 0)

i += Py_SIZE(self);

if (i < 0 || i >= Py_SIZE(self)) {

PyErr_SetString(PyExc_IndexError, "pop index out of range");

return NULL;

}

v = self->ob_item[i];

if (i == Py_SIZE(self) - 1) {

status = list_resize(self, Py_SIZE(self) - 1);

if (status >= 0)

return v; /* and v now owns the reference the list had */

else

return NULL;

}

Py_INCREF(v);

status = list_ass_slice(self, i, i+1, (PyObject *)NULL);

if (status < 0) {

Py_DECREF(v);

return NULL;

}

return v;

}

/* Reverse a slice of a list in place, from lo up to (exclusive) hi. */

static void

reverse_slice(PyObject **lo, PyObject **hi)

{

assert(lo && hi);

--hi;

while (lo < hi) {

PyObject *t = *lo;

*lo = *hi;

*hi = t;

++lo;

--hi;

}

/* Lots of code for an adaptive, stable, natural mergesort. There are many

* pieces to this algorithm; read listsort.txt for overviews and details.

/* A sortslice contains a pointer to an array of keys and a pointer to

* an array of corresponding values. In other words, keys[i]

* corresponds with values[i]. If values == NULL, then the keys are

* also the values.

* Several convenience routines are provided here, so that keys and

* values are always moved in sync.

typedef struct {

PyObject **keys;

PyObject **values;

} sortslice;

Py_LOCAL_INLINE(void)

sortslice_copy(sortslice *s1, Py_ssize_t i, sortslice *s2, Py_ssize_t j)

{

s1->keys[i] = s2->keys[j];

if (s1->values != NULL)

s1->values[i] = s2->values[j];

}

Py_LOCAL_INLINE(void)

sortslice_copy_incr(sortslice *dst, sortslice *src)

{

*dst->keys++ = *src->keys++;

if (dst->values != NULL)

*dst->values++ = *src->values++;

}

View remainder of file in raw view

cpython/Objects/listobject.c at 3.5 · python/cpython · GitHub

Repository navigation

Expand file tree

Breadcrumbs

listobject.c

Latest commit

History

Breadcrumbs

listobject.c

File metadata and controls