phpbb3/phpBB/includes/diff/engine.php at develop · sayedather/phpbb3 · GitHub

History

551 lines (481 loc) · 13.5 KB

Raw

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

<?php

/**

* @package diff

* @license http://opensource.org/licenses/gpl-2.0.php GNU General Public License v2

/**

* @ignore

if (!defined('IN_PHPBB'))

{

exit;

}

/**

* Code from pear.php.net, Text_Diff-1.1.0 package

* http://pear.php.net/package/Text_Diff/ (native engine)

* Modified by phpBB Group to meet our coding standards

* and being able to integrate into phpBB

* Class used internally by Text_Diff to actually compute the diffs. This

* class is implemented using native PHP code.

* The algorithm used here is mostly lifted from the perl module

* Algorithm::Diff (version 1.06) by Ned Konz, which is available at:

* http://www.perl.com/CPAN/authors/id/N/NE/NEDKONZ/Algorithm-Diff-1.06.zip

* More ideas are taken from: http://www.ics.uci.edu/~eppstein/161/960229.html

* Some ideas (and a bit of code) are taken from analyze.c, of GNU

* diffutils-2.7, which can be found at:

* ftp://gnudist.gnu.org/pub/gnu/diffutils/diffutils-2.7.tar.gz

* Some ideas (subdivision by NCHUNKS > 2, and some optimizations) are from

* Geoffrey T. Dairiki <dairiki@dairiki.org>. The original PHP version of this

* code was written by him, and is used/adapted with his permission.

* @author Geoffrey T. Dairiki <dairiki@dairiki.org>

* @package diff

* @access private

class diff_engine

{

/**

* If set to true we trim all lines before we compare them. This ensures that sole space/tab changes do not trigger diffs.

var $skip_whitespace_changes = true;

function diff(&$from_lines, &$to_lines, $preserve_cr = true)

{

// Remove empty lines...

// If preserve_cr is true, we basically only change \r\n and bare \r to \n to get the same carriage returns for both files

// If it is false, we try to only use \n once per line and ommit all empty lines to be able to get a proper data diff

if (is_array($from_lines))

{

$from_lines = implode("\n", $from_lines);

}

if (is_array($to_lines))

{

$to_lines = implode("\n", $to_lines);

}

if ($preserve_cr)

{

$from_lines = explode("\n", str_replace("\r", "\n", str_replace("\r\n", "\n", $from_lines)));

$to_lines = explode("\n", str_replace("\r", "\n", str_replace("\r\n", "\n", $to_lines)));

}

else

{

$from_lines = explode("\n", preg_replace('#[\n\r]+#', "\n", $from_lines));

$to_lines = explode("\n", preg_replace('#[\n\r]+#', "\n", $to_lines));

}

$n_from = sizeof($from_lines);

$n_to = sizeof($to_lines);

$this->xchanged = $this->ychanged = $this->xv = $this->yv = $this->xind = $this->yind = array();

unset($this->seq, $this->in_seq, $this->lcs);

// Skip leading common lines.

for ($skip = 0; $skip < $n_from && $skip < $n_to; $skip++)

{

if (trim($from_lines[$skip]) !== trim($to_lines[$skip]))

{

break;

}

$this->xchanged[$skip] = $this->ychanged[$skip] = false;

}

// Skip trailing common lines.

$xi = $n_from;

$yi = $n_to;

for ($endskip = 0; --$xi > $skip && --$yi > $skip; $endskip++)

{

if (trim($from_lines[$xi]) !== trim($to_lines[$yi]))

{

break;

}

$this->xchanged[$xi] = $this->ychanged[$yi] = false;

}

// Ignore lines which do not exist in both files.

for ($xi = $skip; $xi < $n_from - $endskip; $xi++)

{

if ($this->skip_whitespace_changes) $xhash[trim($from_lines[$xi])] = 1; else $xhash[$from_lines[$xi]] = 1;

}

for ($yi = $skip; $yi < $n_to - $endskip; $yi++)

{

$line = ($this->skip_whitespace_changes) ? trim($to_lines[$yi]) : $to_lines[$yi];

if (($this->ychanged[$yi] = empty($xhash[$line])))

{

continue;

}

$yhash[$line] = 1;

$this->yv[] = $line;

$this->yind[] = $yi;

}

for ($xi = $skip; $xi < $n_from - $endskip; $xi++)

{

$line = ($this->skip_whitespace_changes) ? trim($from_lines[$xi]) : $from_lines[$xi];

if (($this->xchanged[$xi] = empty($yhash[$line])))

{

continue;

}

$this->xv[] = $line;

$this->xind[] = $xi;

}

// Find the LCS.

$this->_compareseq(0, sizeof($this->xv), 0, sizeof($this->yv));

// Merge edits when possible.

if ($this->skip_whitespace_changes)

{

$from_lines_clean = array_map('trim', $from_lines);

$to_lines_clean = array_map('trim', $to_lines);

$this->_shift_boundaries($from_lines_clean, $this->xchanged, $this->ychanged);

$this->_shift_boundaries($to_lines_clean, $this->ychanged, $this->xchanged);

unset($from_lines_clean, $to_lines_clean);

}

else

{

$this->_shift_boundaries($from_lines, $this->xchanged, $this->ychanged);

$this->_shift_boundaries($to_lines, $this->ychanged, $this->xchanged);

}

// Compute the edit operations.

$edits = array();

$xi = $yi = 0;

while ($xi < $n_from || $yi < $n_to)

{

// Skip matching "snake".

$copy = array();

while ($xi < $n_from && $yi < $n_to && !$this->xchanged[$xi] && !$this->ychanged[$yi])

{

$copy[] = $from_lines[$xi++];

$yi++;

}

if ($copy)

{

$edits[] = new diff_op_copy($copy);

}

// Find deletes & adds.

$delete = array();

while ($xi < $n_from && $this->xchanged[$xi])

{

$delete[] = $from_lines[$xi++];

}

$add = array();

while ($yi < $n_to && $this->ychanged[$yi])

{

$add[] = $to_lines[$yi++];

}

if ($delete && $add)

{

$edits[] = new diff_op_change($delete, $add);

}

else if ($delete)

{

$edits[] = new diff_op_delete($delete);

}

else if ($add)

{

$edits[] = new diff_op_add($add);

}

return $edits;

}

/**

* Divides the Largest Common Subsequence (LCS) of the sequences (XOFF,

* XLIM) and (YOFF, YLIM) into NCHUNKS approximately equally sized segments.

* Returns (LCS, PTS). LCS is the length of the LCS. PTS is an array of

* NCHUNKS+1 (X, Y) indexes giving the diving points between sub

* sequences. The first sub-sequence is contained in (X0, X1), (Y0, Y1),

* the second in (X1, X2), (Y1, Y2) and so on. Note that (X0, Y0) ==

* (XOFF, YOFF) and (X[NCHUNKS], Y[NCHUNKS]) == (XLIM, YLIM).

* This function assumes that the first lines of the specified portions of

* the two files do not match, and likewise that the last lines do not

* match. The caller must trim matching lines from the beginning and end

* of the portions it is going to specify.

function _diag($xoff, $xlim, $yoff, $ylim, $nchunks)

{

$flip = false;

if ($xlim - $xoff > $ylim - $yoff)

{

// Things seems faster (I'm not sure I understand why) when the shortest sequence is in X.

$flip = true;

list($xoff, $xlim, $yoff, $ylim) = array($yoff, $ylim, $xoff, $xlim);

}

if ($flip)

{

for ($i = $ylim - 1; $i >= $yoff; $i--)

{

$ymatches[$this->xv[$i]][] = $i;

}

else

{

for ($i = $ylim - 1; $i >= $yoff; $i--)

{

$ymatches[$this->yv[$i]][] = $i;

}

$this->lcs = 0;

$this->seq[0]= $yoff - 1;

$this->in_seq = array();

$ymids[0] = array();

$numer = $xlim - $xoff + $nchunks - 1;

$x = $xoff;

for ($chunk = 0; $chunk < $nchunks; $chunk++)

{

if ($chunk > 0)

{

for ($i = 0; $i <= $this->lcs; $i++)

{

$ymids[$i][$chunk - 1] = $this->seq[$i];

}

$x1 = $xoff + (int)(($numer + ($xlim - $xoff) * $chunk) / $nchunks);

for (; $x < $x1; $x++)

{

$line = $flip ? $this->yv[$x] : $this->xv[$x];

if (empty($ymatches[$line]))

{

continue;

}

$matches = $ymatches[$line];

reset($matches);

while (list(, $y) = each($matches))

{

if (empty($this->in_seq[$y]))

{

$k = $this->_lcs_pos($y);

$ymids[$k] = $ymids[$k - 1];

break;

}

// no reset() here

while (list(, $y) = each($matches))

{

if ($y > $this->seq[$k - 1])

{

// Optimization: this is a common case: next match is just replacing previous match.

$this->in_seq[$this->seq[$k]] = false;

$this->seq[$k] = $y;

$this->in_seq[$y] = 1;

}

else if (empty($this->in_seq[$y]))

{

$k = $this->_lcs_pos($y);

$ymids[$k] = $ymids[$k - 1];

}

$seps[] = $flip ? array($yoff, $xoff) : array($xoff, $yoff);

$ymid = $ymids[$this->lcs];

for ($n = 0; $n < $nchunks - 1; $n++)

{

$x1 = $xoff + (int)(($numer + ($xlim - $xoff) * $n) / $nchunks);

$y1 = $ymid[$n] + 1;

$seps[] = $flip ? array($y1, $x1) : array($x1, $y1);

}

$seps[] = $flip ? array($ylim, $xlim) : array($xlim, $ylim);

return array($this->lcs, $seps);

}

function _lcs_pos($ypos)

{

$end = $this->lcs;

if ($end == 0 || $ypos > $this->seq[$end])

{

$this->seq[++$this->lcs] = $ypos;

$this->in_seq[$ypos] = 1;

return $this->lcs;

}

$beg = 1;

while ($beg < $end)

{

$mid = (int)(($beg + $end) / 2);

if ($ypos > $this->seq[$mid])

{

$beg = $mid + 1;

}

else

{

$end = $mid;

}

$this->in_seq[$this->seq[$end]] = false;

$this->seq[$end] = $ypos;

$this->in_seq[$ypos] = 1;

return $end;

}

/**

* Finds LCS of two sequences.

* The results are recorded in the vectors $this->{x,y}changed[], by

* storing a 1 in the element for each line that is an insertion or

* deletion (ie. is not in the LCS).

* The subsequence of file 0 is (XOFF, XLIM) and likewise for file 1.

* Note that XLIM, YLIM are exclusive bounds. All line numbers are

* origin-0 and discarded lines are not counted.

function _compareseq($xoff, $xlim, $yoff, $ylim)

{

// Slide down the bottom initial diagonal.

while ($xoff < $xlim && $yoff < $ylim && $this->xv[$xoff] == $this->yv[$yoff])

{

++$xoff;

++$yoff;

}

// Slide up the top initial diagonal.

while ($xlim > $xoff && $ylim > $yoff && $this->xv[$xlim - 1] == $this->yv[$ylim - 1])

{

--$xlim;

--$ylim;

}

if ($xoff == $xlim || $yoff == $ylim)

{

$lcs = 0;

}

else

{

// This is ad hoc but seems to work well.

// $nchunks = sqrt(min($xlim - $xoff, $ylim - $yoff) / 2.5);

// $nchunks = max(2,min(8,(int)$nchunks));

$nchunks = min(7, $xlim - $xoff, $ylim - $yoff) + 1;

list($lcs, $seps) = $this->_diag($xoff, $xlim, $yoff, $ylim, $nchunks);

}

if ($lcs == 0)

{

// X and Y sequences have no common subsequence: mark all changed.

while ($yoff < $ylim)

{

$this->ychanged[$this->yind[$yoff++]] = 1;

}

while ($xoff < $xlim)

{

$this->xchanged[$this->xind[$xoff++]] = 1;

}

else

{

// Use the partitions to split this problem into subproblems.

reset($seps);

$pt1 = $seps[0];

while ($pt2 = next($seps))

{

$this->_compareseq($pt1[0], $pt2[0], $pt1[1], $pt2[1]);

$pt1 = $pt2;

}

/**

* Adjusts inserts/deletes of identical lines to join changes as much as possible.

* We do something when a run of changed lines include a line at one end

* and has an excluded, identical line at the other. We are free to

* choose which identical line is included. 'compareseq' usually chooses

* the one at the beginning, but usually it is cleaner to consider the

* following identical line to be the "change".

* This is extracted verbatim from analyze.c (GNU diffutils-2.7).

function _shift_boundaries($lines, &$changed, $other_changed)

{

$i = 0;

$j = 0;

$len = sizeof($lines);

$other_len = sizeof($other_changed);

while (1)

{

// Scan forward to find the beginning of another run of

// changes. Also keep track of the corresponding point in the other file.

// Throughout this code, $i and $j are adjusted together so that

// the first $i elements of $changed and the first $j elements of

// $other_changed both contain the same number of zeros (unchanged lines).

// Furthermore, $j is always kept so that $j == $other_len or $other_changed[$j] == false.

while ($j < $other_len && $other_changed[$j])

{

$j++;

}

while ($i < $len && ! $changed[$i])

{

$i++;

$j++;

while ($j < $other_len && $other_changed[$j])

{

$j++;

}

if ($i == $len)

{

break;

}

$start = $i;

// Find the end of this run of changes.

while (++$i < $len && $changed[$i])

{

continue;

}

{

// Record the length of this run of changes, so that we can later determine whether the run has grown.

$runlength = $i - $start;

// Move the changed region back, so long as the previous unchanged line matches the last changed one.

// This merges with previous changed regions.

while ($start > 0 && $lines[$start - 1] == $lines[$i - 1])

{

$changed[--$start] = 1;

$changed[--$i] = false;

while ($start > 0 && $changed[$start - 1])

{

$start--;

}

while ($other_changed[--$j])

{

continue;

}

// Set CORRESPONDING to the end of the changed run, at the last point where it corresponds to a changed run in the

// other file. CORRESPONDING == LEN means no such point has been found.

$corresponding = $j < $other_len ? $i : $len;

// Move the changed region forward, so long as the first changed line matches the following unchanged one.

// This merges with following changed regions.

// Do this second, so that if there are no merges, the changed region is moved forward as far as possible.

while ($i < $len && $lines[$start] == $lines[$i])

{

$changed[$start++] = false;

$changed[$i++] = 1;

while ($i < $len && $changed[$i])

{

$i++;

}

$j++;

if ($j < $other_len && $other_changed[$j])

{

$corresponding = $i;

while ($j < $other_len && $other_changed[$j])

{

$j++;

}

while ($runlength != $i - $start);

// If possible, move the fully-merged run of changes back to a corresponding run in the other file.

while ($corresponding < $i)

{

$changed[--$start] = 1;

$changed[--$i] = 0;

while ($other_changed[--$j])

{

continue;

}

phpbb3/phpBB/includes/diff/engine.php at develop · sayedather/phpbb3 · GitHub

Expand file tree

Breadcrumbs

engine.php

Latest commit

History

Breadcrumbs

engine.php

File metadata and controls