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Direktori : /home2/selectio/www/fms-worksuite/vendor/nikic/php-parser/lib/PhpParser/Internal/ |
Current File : /home2/selectio/www/fms-worksuite/vendor/nikic/php-parser/lib/PhpParser/Internal/Differ.php |
<?php declare(strict_types=1); namespace PhpParser\Internal; /** * Implements the Myers diff algorithm. * * Myers, Eugene W. "An O (ND) difference algorithm and its variations." * Algorithmica 1.1 (1986): 251-266. * * @internal */ class Differ { private $isEqual; /** * Create differ over the given equality relation. * * @param callable $isEqual Equality relation with signature function($a, $b) : bool */ public function __construct(callable $isEqual) { $this->isEqual = $isEqual; } /** * Calculate diff (edit script) from $old to $new. * * @param array $old Original array * @param array $new New array * * @return DiffElem[] Diff (edit script) */ public function diff(array $old, array $new) { list($trace, $x, $y) = $this->calculateTrace($old, $new); return $this->extractDiff($trace, $x, $y, $old, $new); } /** * Calculate diff, including "replace" operations. * * If a sequence of remove operations is followed by the same number of add operations, these * will be coalesced into replace operations. * * @param array $old Original array * @param array $new New array * * @return DiffElem[] Diff (edit script), including replace operations */ public function diffWithReplacements(array $old, array $new) { return $this->coalesceReplacements($this->diff($old, $new)); } private function calculateTrace(array $a, array $b) { $n = \count($a); $m = \count($b); $max = $n + $m; $v = [1 => 0]; $trace = []; for ($d = 0; $d <= $max; $d++) { $trace[] = $v; for ($k = -$d; $k <= $d; $k += 2) { if ($k === -$d || ($k !== $d && $v[$k-1] < $v[$k+1])) { $x = $v[$k+1]; } else { $x = $v[$k-1] + 1; } $y = $x - $k; while ($x < $n && $y < $m && ($this->isEqual)($a[$x], $b[$y])) { $x++; $y++; } $v[$k] = $x; if ($x >= $n && $y >= $m) { return [$trace, $x, $y]; } } } throw new \Exception('Should not happen'); } private function extractDiff(array $trace, int $x, int $y, array $a, array $b) { $result = []; for ($d = \count($trace) - 1; $d >= 0; $d--) { $v = $trace[$d]; $k = $x - $y; if ($k === -$d || ($k !== $d && $v[$k-1] < $v[$k+1])) { $prevK = $k + 1; } else { $prevK = $k - 1; } $prevX = $v[$prevK]; $prevY = $prevX - $prevK; while ($x > $prevX && $y > $prevY) { $result[] = new DiffElem(DiffElem::TYPE_KEEP, $a[$x-1], $b[$y-1]); $x--; $y--; } if ($d === 0) { break; } while ($x > $prevX) { $result[] = new DiffElem(DiffElem::TYPE_REMOVE, $a[$x-1], null); $x--; } while ($y > $prevY) { $result[] = new DiffElem(DiffElem::TYPE_ADD, null, $b[$y-1]); $y--; } } return array_reverse($result); } /** * Coalesce equal-length sequences of remove+add into a replace operation. * * @param DiffElem[] $diff * @return DiffElem[] */ private function coalesceReplacements(array $diff) { $newDiff = []; $c = \count($diff); for ($i = 0; $i < $c; $i++) { $diffType = $diff[$i]->type; if ($diffType !== DiffElem::TYPE_REMOVE) { $newDiff[] = $diff[$i]; continue; } $j = $i; while ($j < $c && $diff[$j]->type === DiffElem::TYPE_REMOVE) { $j++; } $k = $j; while ($k < $c && $diff[$k]->type === DiffElem::TYPE_ADD) { $k++; } if ($j - $i === $k - $j) { $len = $j - $i; for ($n = 0; $n < $len; $n++) { $newDiff[] = new DiffElem( DiffElem::TYPE_REPLACE, $diff[$i + $n]->old, $diff[$j + $n]->new ); } } else { for (; $i < $k; $i++) { $newDiff[] = $diff[$i]; } } $i = $k - 1; } return $newDiff; } }