cpython/Objects/stringlib/unicode_format.h at v3.6.15 · 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

unicode_format.h -- implementation of str.format().

/************************************************************************/

/*********** Global data structures and forward declarations *********/

/************************************************************************/

A SubString consists of the characters between two string or

unicode pointers.

typedef struct {

PyObject *str; /* borrowed reference */

Py_ssize_t start, end;

} SubString;

typedef enum {

ANS_INIT,

ANS_AUTO,

ANS_MANUAL

} AutoNumberState; /* Keep track if we're auto-numbering fields */

/* Keeps track of our auto-numbering state, and which number field we're on */

typedef struct {

AutoNumberState an_state;

int an_field_number;

} AutoNumber;

/* forward declaration for recursion */

static PyObject *

build_string(SubString *input, PyObject *args, PyObject *kwargs,

int recursion_depth, AutoNumber *auto_number);

/************************************************************************/

/************************** Utility functions ************************/

/************************************************************************/

static void

AutoNumber_Init(AutoNumber *auto_number)

{

auto_number->an_state = ANS_INIT;

auto_number->an_field_number = 0;

}

/* fill in a SubString from a pointer and length */

Py_LOCAL_INLINE(void)

SubString_init(SubString *str, PyObject *s, Py_ssize_t start, Py_ssize_t end)

{

str->str = s;

str->start = start;

str->end = end;

}

/* return a new string. if str->str is NULL, return None */

Py_LOCAL_INLINE(PyObject *)

SubString_new_object(SubString *str)

{

if (str->str == NULL) {

Py_INCREF(Py_None);

return Py_None;

}

return PyUnicode_Substring(str->str, str->start, str->end);

}

/* return a new string. if str->str is NULL, return a new empty string */

Py_LOCAL_INLINE(PyObject *)

SubString_new_object_or_empty(SubString *str)

{

if (str->str == NULL) {

return PyUnicode_New(0, 0);

}

return SubString_new_object(str);

}

/* Return 1 if an error has been detected switching between automatic

field numbering and manual field specification, else return 0. Set

ValueError on error. */

static int

autonumber_state_error(AutoNumberState state, int field_name_is_empty)

{

if (state == ANS_MANUAL) {

if (field_name_is_empty) {

PyErr_SetString(PyExc_ValueError, "cannot switch from "

"manual field specification to "

"automatic field numbering");

return 1;

}

else {

if (!field_name_is_empty) {

PyErr_SetString(PyExc_ValueError, "cannot switch from "

"automatic field numbering to "

"manual field specification");

return 1;

}

return 0;

}

/************************************************************************/

/*********** Format string parsing -- integers and identifiers *********/

/************************************************************************/

static Py_ssize_t

get_integer(const SubString *str)

{

Py_ssize_t accumulator = 0;

Py_ssize_t digitval;

Py_ssize_t i;

/* empty string is an error */

if (str->start >= str->end)

return -1;

for (i = str->start; i < str->end; i++) {

digitval = Py_UNICODE_TODECIMAL(PyUnicode_READ_CHAR(str->str, i));

if (digitval < 0)

return -1;

Detect possible overflow before it happens:

accumulator * 10 + digitval > PY_SSIZE_T_MAX if and only if

accumulator > (PY_SSIZE_T_MAX - digitval) / 10.

if (accumulator > (PY_SSIZE_T_MAX - digitval) / 10) {

PyErr_Format(PyExc_ValueError,

"Too many decimal digits in format string");

return -1;

}

accumulator = accumulator * 10 + digitval;

}

return accumulator;

}

/************************************************************************/

/******** Functions to get field objects and specification strings ******/

/************************************************************************/

/* do the equivalent of obj.name */

static PyObject *

getattr(PyObject *obj, SubString *name)

{

PyObject *newobj;

PyObject *str = SubString_new_object(name);

if (str == NULL)

return NULL;

newobj = PyObject_GetAttr(obj, str);

Py_DECREF(str);

return newobj;

}

/* do the equivalent of obj[idx], where obj is a sequence */

static PyObject *

getitem_sequence(PyObject *obj, Py_ssize_t idx)

{

return PySequence_GetItem(obj, idx);

}

/* do the equivalent of obj[idx], where obj is not a sequence */

static PyObject *

getitem_idx(PyObject *obj, Py_ssize_t idx)

{

PyObject *newobj;

PyObject *idx_obj = PyLong_FromSsize_t(idx);

if (idx_obj == NULL)

return NULL;

newobj = PyObject_GetItem(obj, idx_obj);

Py_DECREF(idx_obj);

return newobj;

}

/* do the equivalent of obj[name] */

static PyObject *

getitem_str(PyObject *obj, SubString *name)

{

PyObject *newobj;

PyObject *str = SubString_new_object(name);

if (str == NULL)

return NULL;

newobj = PyObject_GetItem(obj, str);

Py_DECREF(str);

return newobj;

}

typedef struct {

/* the entire string we're parsing. we assume that someone else

is managing its lifetime, and that it will exist for the

lifetime of the iterator. can be empty */

SubString str;

/* index to where we are inside field_name */

Py_ssize_t index;

} FieldNameIterator;

static int

FieldNameIterator_init(FieldNameIterator *self, PyObject *s,

Py_ssize_t start, Py_ssize_t end)

{

SubString_init(&self->str, s, start, end);

self->index = start;

return 1;

}

static int

_FieldNameIterator_attr(FieldNameIterator *self, SubString *name)

{

Py_UCS4 c;

name->str = self->str.str;

name->start = self->index;

/* return everything until '.' or '[' */

while (self->index < self->str.end) {

c = PyUnicode_READ_CHAR(self->str.str, self->index++);

switch (c) {

case '[':

case '.':

/* backup so that we this character will be seen next time */

self->index--;

break;

default:

continue;

}

break;

}

/* end of string is okay */

name->end = self->index;

return 1;

}

static int

_FieldNameIterator_item(FieldNameIterator *self, SubString *name)

{

int bracket_seen = 0;

Py_UCS4 c;

name->str = self->str.str;

name->start = self->index;

/* return everything until ']' */

while (self->index < self->str.end) {

c = PyUnicode_READ_CHAR(self->str.str, self->index++);

switch (c) {

case ']':

bracket_seen = 1;

break;

default:

continue;

}

break;

}

/* make sure we ended with a ']' */

if (!bracket_seen) {

PyErr_SetString(PyExc_ValueError, "Missing ']' in format string");

return 0;

}

/* end of string is okay */

/* don't include the ']' */

name->end = self->index-1;

return 1;

}

/* returns 0 on error, 1 on non-error termination, and 2 if it returns a value */

static int

FieldNameIterator_next(FieldNameIterator *self, int *is_attribute,

Py_ssize_t *name_idx, SubString *name)

{

/* check at end of input */

if (self->index >= self->str.end)

return 1;

switch (PyUnicode_READ_CHAR(self->str.str, self->index++)) {

case '.':

*is_attribute = 1;

if (_FieldNameIterator_attr(self, name) == 0)

return 0;

*name_idx = -1;

break;

case '[':

*is_attribute = 0;

if (_FieldNameIterator_item(self, name) == 0)

return 0;

*name_idx = get_integer(name);

if (*name_idx == -1 && PyErr_Occurred())

return 0;

break;

default:

/* Invalid character follows ']' */

PyErr_SetString(PyExc_ValueError, "Only '.' or '[' may "

"follow ']' in format field specifier");

return 0;

}

/* empty string is an error */

if (name->start == name->end) {

PyErr_SetString(PyExc_ValueError, "Empty attribute in format string");

return 0;

}

return 2;

}

/* input: field_name

output: 'first' points to the part before the first '[' or '.'

'first_idx' is -1 if 'first' is not an integer, otherwise

it's the value of first converted to an integer

'rest' is an iterator to return the rest

static int

field_name_split(PyObject *str, Py_ssize_t start, Py_ssize_t end, SubString *first,

Py_ssize_t *first_idx, FieldNameIterator *rest,

AutoNumber *auto_number)

{

Py_UCS4 c;

Py_ssize_t i = start;

int field_name_is_empty;

int using_numeric_index;

/* find the part up until the first '.' or '[' */

while (i < end) {

switch (c = PyUnicode_READ_CHAR(str, i++)) {

case '[':

case '.':

/* backup so that we this character is available to the

"rest" iterator */

i--;

break;

default:

continue;

}

break;

}

/* set up the return values */

SubString_init(first, str, start, i);

FieldNameIterator_init(rest, str, i, end);

/* see if "first" is an integer, in which case it's used as an index */

*first_idx = get_integer(first);

if (*first_idx == -1 && PyErr_Occurred())

return 0;

field_name_is_empty = first->start >= first->end;

/* If the field name is omitted or if we have a numeric index

specified, then we're doing numeric indexing into args. */

using_numeric_index = field_name_is_empty || *first_idx != -1;

/* We always get here exactly one time for each field we're

processing. And we get here in field order (counting by left

braces). So this is the perfect place to handle automatic field

numbering if the field name is omitted. */

/* Check if we need to do the auto-numbering. It's not needed if

we're called from string.Format routines, because it's handled

in that class by itself. */

if (auto_number) {

/* Initialize our auto numbering state if this is the first

time we're either auto-numbering or manually numbering. */

if (auto_number->an_state == ANS_INIT && using_numeric_index)

auto_number->an_state = field_name_is_empty ?

ANS_AUTO : ANS_MANUAL;

/* Make sure our state is consistent with what we're doing

this time through. Only check if we're using a numeric

index. */

if (using_numeric_index)

if (autonumber_state_error(auto_number->an_state,

field_name_is_empty))

return 0;

/* Zero length field means we want to do auto-numbering of the

fields. */

if (field_name_is_empty)

*first_idx = (auto_number->an_field_number)++;

}

return 1;

}

get_field_object returns the object inside {}, before the

format_spec. It handles getindex and getattr lookups and consumes

the entire input string.

static PyObject *

get_field_object(SubString *input, PyObject *args, PyObject *kwargs,

AutoNumber *auto_number)

{

PyObject *obj = NULL;

int ok;

int is_attribute;

SubString name;

SubString first;

Py_ssize_t index;

FieldNameIterator rest;

if (!field_name_split(input->str, input->start, input->end, &first,

&index, &rest, auto_number)) {

goto error;

}

if (index == -1) {

/* look up in kwargs */

PyObject *key = SubString_new_object(&first);

if (key == NULL) {

goto error;

}

if (kwargs == NULL) {

PyErr_SetObject(PyExc_KeyError, key);

Py_DECREF(key);

goto error;

}

/* Use PyObject_GetItem instead of PyDict_GetItem because this

code is no longer just used with kwargs. It might be passed

a non-dict when called through format_map. */

obj = PyObject_GetItem(kwargs, key);

Py_DECREF(key);

if (obj == NULL) {

goto error;

}

else {

/* If args is NULL, we have a format string with a positional field

with only kwargs to retrieve it from. This can only happen when

used with format_map(), where positional arguments are not

allowed. */

if (args == NULL) {

PyErr_SetString(PyExc_ValueError, "Format string contains "

"positional fields");

goto error;

}

/* look up in args */

obj = PySequence_GetItem(args, index);

if (obj == NULL)

goto error;

}

/* iterate over the rest of the field_name */

while ((ok = FieldNameIterator_next(&rest, &is_attribute, &index,

&name)) == 2) {

PyObject *tmp;

if (is_attribute)

/* getattr lookup "." */

tmp = getattr(obj, &name);

else

/* getitem lookup "[]" */

if (index == -1)

tmp = getitem_str(obj, &name);

else

if (PySequence_Check(obj))

tmp = getitem_sequence(obj, index);

else

/* not a sequence */

tmp = getitem_idx(obj, index);

if (tmp == NULL)

goto error;

/* assign to obj */

Py_DECREF(obj);

obj = tmp;

}

/* end of iterator, this is the non-error case */

if (ok == 1)

return obj;

error:

Py_XDECREF(obj);

return NULL;

}

/************************************************************************/

/***************** Field rendering functions **************************/

/************************************************************************/

render_field() is the main function in this section. It takes the

field object and field specification string generated by

get_field_and_spec, and renders the field into the output string.

render_field calls fieldobj.__format__(format_spec) method, and

appends to the output.

static int

render_field(PyObject *fieldobj, SubString *format_spec, _PyUnicodeWriter *writer)

{

int ok = 0;

PyObject *result = NULL;

PyObject *format_spec_object = NULL;

int (*formatter) (_PyUnicodeWriter*, PyObject *, PyObject *, Py_ssize_t, Py_ssize_t) = NULL;

int err;

/* If we know the type exactly, skip the lookup of __format__ and just

call the formatter directly. */

if (PyUnicode_CheckExact(fieldobj))

formatter = _PyUnicode_FormatAdvancedWriter;

else if (PyLong_CheckExact(fieldobj))

formatter = _PyLong_FormatAdvancedWriter;

else if (PyFloat_CheckExact(fieldobj))

formatter = _PyFloat_FormatAdvancedWriter;

else if (PyComplex_CheckExact(fieldobj))

formatter = _PyComplex_FormatAdvancedWriter;

if (formatter) {

/* we know exactly which formatter will be called when __format__ is

looked up, so call it directly, instead. */

err = formatter(writer, fieldobj, format_spec->str,

format_spec->start, format_spec->end);

return (err == 0);

}

else {

/* We need to create an object out of the pointers we have, because

__format__ takes a string/unicode object for format_spec. */

if (format_spec->str)

format_spec_object = PyUnicode_Substring(format_spec->str,

format_spec->start,

format_spec->end);

else

format_spec_object = PyUnicode_New(0, 0);

if (format_spec_object == NULL)

goto done;

result = PyObject_Format(fieldobj, format_spec_object);

}

if (result == NULL)

goto done;

if (_PyUnicodeWriter_WriteStr(writer, result) == -1)

goto done;

ok = 1;

done:

Py_XDECREF(format_spec_object);

Py_XDECREF(result);

return ok;

}

static int

parse_field(SubString *str, SubString *field_name, SubString *format_spec,

int *format_spec_needs_expanding, Py_UCS4 *conversion)

{

/* Note this function works if the field name is zero length,

which is good. Zero length field names are handled later, in

field_name_split. */

Py_UCS4 c = 0;

/* initialize these, as they may be empty */

*conversion = '\0';

SubString_init(format_spec, NULL, 0, 0);

/* Search for the field name. it's terminated by the end of

the string, or a ':' or '!' */

field_name->str = str->str;

field_name->start = str->start;

while (str->start < str->end) {

switch ((c = PyUnicode_READ_CHAR(str->str, str->start++))) {

case '{':

PyErr_SetString(PyExc_ValueError, "unexpected '{' in field name");

return 0;

case '[':

for (; str->start < str->end; str->start++)

if (PyUnicode_READ_CHAR(str->str, str->start) == ']')

break;

continue;

case '}':

case ':':

case '!':

break;

default:

continue;

}

break;

}

field_name->end = str->start - 1;

if (c == '!' || c == ':') {

Py_ssize_t count;

/* we have a format specifier and/or a conversion */

/* don't include the last character */

/* see if there's a conversion specifier */

if (c == '!') {

/* there must be another character present */

if (str->start >= str->end) {

PyErr_SetString(PyExc_ValueError,

"end of string while looking for conversion "

"specifier");

return 0;

}

*conversion = PyUnicode_READ_CHAR(str->str, str->start++);

if (str->start < str->end) {

c = PyUnicode_READ_CHAR(str->str, str->start++);

if (c == '}')

return 1;

if (c != ':') {

PyErr_SetString(PyExc_ValueError,

"expected ':' after conversion specifier");

return 0;

}

format_spec->str = str->str;

format_spec->start = str->start;

count = 1;

while (str->start < str->end) {

switch ((c = PyUnicode_READ_CHAR(str->str, str->start++))) {

case '{':

*format_spec_needs_expanding = 1;

count++;

break;

case '}':

count--;

if (count == 0) {

format_spec->end = str->start - 1;

return 1;

}

break;

default:

break;

}

PyErr_SetString(PyExc_ValueError, "unmatched '{' in format spec");

return 0;

}

else if (c != '}') {

PyErr_SetString(PyExc_ValueError, "expected '}' before end of string");

return 0;

}

return 1;

}

/************************************************************************/

/******* Output string allocation and escape-to-markup processing ******/

/************************************************************************/

/* MarkupIterator breaks the string into pieces of either literal

text, or things inside {} that need to be marked up. it is

designed to make it easy to wrap a Python iterator around it, for

use with the Formatter class */

typedef struct {

SubString str;

} MarkupIterator;

static int

MarkupIterator_init(MarkupIterator *self, PyObject *str,

Py_ssize_t start, Py_ssize_t end)

{

SubString_init(&self->str, str, start, end);

return 1;

}

/* returns 0 on error, 1 on non-error termination, and 2 if it got a

string (or something to be expanded) */

static int

MarkupIterator_next(MarkupIterator *self, SubString *literal,

int *field_present, SubString *field_name,

SubString *format_spec, Py_UCS4 *conversion,

int *format_spec_needs_expanding)

{

int at_end;

Py_UCS4 c = 0;

Py_ssize_t start;

Py_ssize_t len;

int markup_follows = 0;

/* initialize all of the output variables */

SubString_init(literal, NULL, 0, 0);

SubString_init(field_name, NULL, 0, 0);

SubString_init(format_spec, NULL, 0, 0);

*conversion = '\0';

*format_spec_needs_expanding = 0;

*field_present = 0;

/* No more input, end of iterator. This is the normal exit

path. */

if (self->str.start >= self->str.end)

return 1;

start = self->str.start;

/* First read any literal text. Read until the end of string, an

escaped '{' or '}', or an unescaped '{'. In order to never

allocate memory and so I can just pass pointers around, if

there's an escaped '{' or '}' then we'll return the literal

including the brace, but no format object. The next time

through, we'll return the rest of the literal, skipping past

the second consecutive brace. */

while (self->str.start < self->str.end) {

switch (c = PyUnicode_READ_CHAR(self->str.str, self->str.start++)) {

case '{':

case '}':

markup_follows = 1;

break;

default:

continue;

}

break;

}

at_end = self->str.start >= self->str.end;

len = self->str.start - start;

if ((c == '}') && (at_end ||

(c != PyUnicode_READ_CHAR(self->str.str,

self->str.start)))) {

PyErr_SetString(PyExc_ValueError, "Single '}' encountered "

"in format string");

return 0;

}

if (at_end && c == '{') {

PyErr_SetString(PyExc_ValueError, "Single '{' encountered "

"in format string");

return 0;

}

if (!at_end) {

if (c == PyUnicode_READ_CHAR(self->str.str, self->str.start)) {

/* escaped } or {, skip it in the input. there is no

markup object following us, just this literal text */

self->str.start++;

markup_follows = 0;

}

else

len--;

}

/* record the literal text */

literal->str = self->str.str;

literal->start = start;

literal->end = start + len;

if (!markup_follows)

return 2;

/* this is markup; parse the field */

*field_present = 1;

if (!parse_field(&self->str, field_name, format_spec,

format_spec_needs_expanding, conversion))

return 0;

return 2;

}

/* do the !r or !s conversion on obj */

static PyObject *

do_conversion(PyObject *obj, Py_UCS4 conversion)

{

/* XXX in pre-3.0, do we need to convert this to unicode, since it

might have returned a string? */

switch (conversion) {

case 'r':

return PyObject_Repr(obj);

case 's':

return PyObject_Str(obj);

case 'a':

return PyObject_ASCII(obj);

default:

if (conversion > 32 && conversion < 127) {

/* It's the ASCII subrange; casting to char is safe

(assuming the execution character set is an ASCII

superset). */

PyErr_Format(PyExc_ValueError,

"Unknown conversion specifier %c",

(char)conversion);

} else

PyErr_Format(PyExc_ValueError,

"Unknown conversion specifier \\x%x",

(unsigned int)conversion);

return NULL;

}

/* given:

{field_name!conversion:format_spec}

compute the result and write it to output.

format_spec_needs_expanding is an optimization. if it's false,

just output the string directly, otherwise recursively expand the

format_spec string.

field_name is allowed to be zero length, in which case we

are doing auto field numbering.

static int

output_markup(SubString *field_name, SubString *format_spec,

int format_spec_needs_expanding, Py_UCS4 conversion,

_PyUnicodeWriter *writer, PyObject *args, PyObject *kwargs,

int recursion_depth, AutoNumber *auto_number)

{

PyObject *tmp = NULL;

PyObject *fieldobj = NULL;

SubString expanded_format_spec;

SubString *actual_format_spec;

int result = 0;

/* convert field_name to an object */

fieldobj = get_field_object(field_name, args, kwargs, auto_number);

if (fieldobj == NULL)

goto done;

if (conversion != '\0') {

tmp = do_conversion(fieldobj, conversion);

if (tmp == NULL || PyUnicode_READY(tmp) == -1)

goto done;

/* do the assignment, transferring ownership: fieldobj = tmp */

Py_DECREF(fieldobj);

fieldobj = tmp;

tmp = NULL;

}

/* if needed, recurively compute the format_spec */

if (format_spec_needs_expanding) {

tmp = build_string(format_spec, args, kwargs, recursion_depth-1,

auto_number);

if (tmp == NULL || PyUnicode_READY(tmp) == -1)

goto done;

/* note that in the case we're expanding the format string,

tmp must be kept around until after the call to

render_field. */

SubString_init(&expanded_format_spec, tmp, 0, PyUnicode_GET_LENGTH(tmp));

actual_format_spec = &expanded_format_spec;

}

else

actual_format_spec = format_spec;

if (render_field(fieldobj, actual_format_spec, writer) == 0)

goto done;

result = 1;

done:

Py_XDECREF(fieldobj);

Py_XDECREF(tmp);

return result;

}

do_markup is the top-level loop for the format() method. It

searches through the format string for escapes to markup codes, and

calls other functions to move non-markup text to the output,

and to perform the markup to the output.

static int

do_markup(SubString *input, PyObject *args, PyObject *kwargs,

_PyUnicodeWriter *writer, int recursion_depth, AutoNumber *auto_number)

{

MarkupIterator iter;

int format_spec_needs_expanding;

int result;

int field_present;

SubString literal;

SubString field_name;

SubString format_spec;

Py_UCS4 conversion;

MarkupIterator_init(&iter, input->str, input->start, input->end);

while ((result = MarkupIterator_next(&iter, &literal, &field_present,

&field_name, &format_spec,

&conversion,

&format_spec_needs_expanding)) == 2) {

if (literal.end != literal.start) {

if (!field_present && iter.str.start == iter.str.end)

writer->overallocate = 0;

if (_PyUnicodeWriter_WriteSubstring(writer, literal.str,

literal.start, literal.end) < 0)

return 0;

}

if (field_present) {

if (iter.str.start == iter.str.end)

writer->overallocate = 0;

if (!output_markup(&field_name, &format_spec,

format_spec_needs_expanding, conversion, writer,

args, kwargs, recursion_depth, auto_number))

return 0;

}

return result;

}

build_string allocates the output string and then

calls do_markup to do the heavy lifting.

static PyObject *

build_string(SubString *input, PyObject *args, PyObject *kwargs,

int recursion_depth, AutoNumber *auto_number)

{

_PyUnicodeWriter writer;

/* check the recursion level */

if (recursion_depth <= 0) {

PyErr_SetString(PyExc_ValueError,

"Max string recursion exceeded");

return NULL;

}

_PyUnicodeWriter_Init(&writer);

writer.overallocate = 1;

writer.min_length = PyUnicode_GET_LENGTH(input->str) + 100;

if (!do_markup(input, args, kwargs, &writer, recursion_depth,

auto_number)) {

_PyUnicodeWriter_Dealloc(&writer);

return NULL;

}

return _PyUnicodeWriter_Finish(&writer);

}

/************************************************************************/

/*********** main routine ***********************************************/

/************************************************************************/

/* this is the main entry point */

static PyObject *

do_string_format(PyObject *self, PyObject *args, PyObject *kwargs)

{

SubString input;

/* PEP 3101 says only 2 levels, so that

"{0:{1}}".format('abc', 's') # works

"{0:{1:{2}}}".format('abc', 's', '') # fails

int recursion_depth = 2;

AutoNumber auto_number;

if (PyUnicode_READY(self) == -1)

return NULL;

AutoNumber_Init(&auto_number);

SubString_init(&input, self, 0, PyUnicode_GET_LENGTH(self));

return build_string(&input, args, kwargs, recursion_depth, &auto_number);

}

static PyObject *

do_string_format_map(PyObject *self, PyObject *obj)

{

return do_string_format(self, NULL, obj);

}

/************************************************************************/

/*********** formatteriterator ******************************************/

/************************************************************************/

/* This is used to implement string.Formatter.vparse(). It exists so

Formatter can share code with the built in unicode.format() method.

It's really just a wrapper around MarkupIterator that is callable

from Python. */

typedef struct {

PyObject_HEAD

PyObject *str;

MarkupIterator it_markup;

} formatteriterobject;

static void

formatteriter_dealloc(formatteriterobject *it)

{

Py_XDECREF(it->str);

PyObject_FREE(it);

}

/* returns a tuple:

(literal, field_name, format_spec, conversion)

literal is any literal text to output. might be zero length

field_name is the string before the ':'. might be None

format_spec is the string after the ':'. mibht be None

conversion is either None, or the string after the '!'

static PyObject *

formatteriter_next(formatteriterobject *it)

{

SubString literal;

SubString field_name;

SubString format_spec;

Py_UCS4 conversion;

View remainder of file in raw view

cpython/Objects/stringlib/unicode_format.h at v3.6.15 · python/cpython · GitHub

Repository navigation

Expand file tree

Breadcrumbs

unicode_format.h

Latest commit

History

Breadcrumbs

unicode_format.h

File metadata and controls