92 lines
2.7 KiB
PHP
92 lines
2.7 KiB
PHP
<?php
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/*
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* This file is part of the Symfony package.
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*
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* (c) Fabien Potencier <fabien@symfony.com>
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*
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* For the full copyright and license information, please view the LICENSE
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* file that was distributed with this source code.
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*/
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namespace Sensio\Bundle\DistributionBundle\Diff;
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/**
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* Computes a Diff between files (line by line).
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*
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* Implements the Longest common subsequence problem algorithm.
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*
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* @see http://en.wikipedia.org/wiki/Longest_common_subsequence_problem
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*
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* @author Fabien Potencier <fabien@symfony.com>
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*/
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class Diff
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{
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private $diff;
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public function __construct($str1, $str2)
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{
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$lines1 = explode("\n", $str1);
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$lines2 = explode("\n", $str2);
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$this->diff = $this->computeDiff($this->computeLcs($lines1, $lines2), $lines1, $lines2, count($lines1) - 1, count($lines2) - 1);
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}
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public function getDiff()
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{
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$diff = array();
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for ($i = 0, $max = count($this->diff); $i < $max; $i++) {
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if ('' != $this->diff[$i][0]) {
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$diff[] = array('@', sprintf(' Line %s', $this->diff[$i][2]));
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do {
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$diff[] = $this->diff[$i++];
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} while ('' != $this->diff[$i][0]);
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}
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}
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return $diff;
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}
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public function computeDiff(array $c, array $lines1, array $lines2, $i, $j)
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{
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$diff = array();
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if ($i > -1 && $j > -1 && $lines1[$i] == $lines2[$j]) {
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$diff = array_merge($diff, $this->computeDiff($c, $lines1, $lines2, $i - 1, $j - 1));
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$diff[] = array('', $lines1[$i], $i, $j);
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} else {
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if ($j > -1 && ($i == -1 || $c[$i][$j - 1] >= $c[$i - 1][$j])) {
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$diff = array_merge($diff, $this->computeDiff($c, $lines1, $lines2, $i, $j - 1));
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$diff[] = array('+', $lines2[$j], $i, $j);
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} elseif ($i > -1 && ($j == -1 || $c[$i][$j - 1] < $c[$i - 1][$j])) {
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$diff = array_merge($diff, $this->computeDiff($c, $lines1, $lines2, $i - 1, $j));
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$diff[] = array('-', $lines1[$i], $i, $j);
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}
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}
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return $diff;
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}
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private function computeLcs(array $lines1, array $lines2)
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{
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for ($i = -1, $len1 = count($lines1); $i < $len1; $i++) {
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for ($j = -1, $len2 = count($lines2); $j < $len2; $j++) {
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$c[$i][$j] = 0;
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}
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}
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for ($i = 0; $i < $len1; $i++) {
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for ($j = 0; $j < $len2; $j++) {
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if ($lines1[$i] == $lines2[$j]) {
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$c[$i][$j] = $c[$i - 1][$j - 1] + 1;
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} else {
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$c[$i][$j] = max($c[$i][$j - 1], $c[$i - 1][$j]);
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}
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}
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}
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return $c;
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}
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}
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