protected DiffEngine::_compareseq($xoff, $xlim, $yoff, $ylim)
Find LCS of two sequences.
The results are recorded in the vectors $this->{x,y}changed[], by storing a 1 in the element for each line that is an insertion or deletion (ie. is not in the LCS).
The subsequence of file 0 is [XOFF, XLIM) and likewise for file 1.
Note that XLIM, YLIM are exclusive bounds. All line numbers are origin-0 and discarded lines are not counted.
File
- core/lib/Drupal/Component/Diff/Engine/DiffEngine.php, line 283
Class
- DiffEngine
- Class used internally by Diff to actually compute the diffs.
Namespace
Drupal\Component\Diff\Engine
Code
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 | protected function _compareseq($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; } }} |
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