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<?php
/**
* A PHP diff engine for phpwiki. (Taken from phpwiki-1.3.3)
*
* Copyright © 2000, 2001 Geoffrey T. Dairiki <dairiki@dairiki.org>
* You may copy this code freely under the conditions of the GPL.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
* http://www.gnu.org/copyleft/gpl.html
*
* @file
* @ingroup DifferenceEngine
*/
/**
* Class representing a 'diff' between two sequences of strings.
* @newable
* @ingroup DifferenceEngine
*/
class Diff {
/**
* @var DiffOp[]
*/
public $edits;
/**
* @var int If this diff complexity is exceeded, a ComplexityException is thrown
* 0 means no limit.
*/
protected $bailoutComplexity = 0;
/**
* Computes diff between sequences of strings.
*
* @stable for calling
* @todo Don't do work in the constructor, use a service to create diffs instead (T257472).
*
* @param string[] $from_lines An array of strings.
* Typically these are lines from a file.
* @param string[] $to_lines An array of strings.
* @throws \MediaWiki\Diff\ComplexityException
*/
public function __construct( $from_lines, $to_lines ) {
$eng = new DiffEngine;
$eng->setBailoutComplexity( $this->bailoutComplexity );
$this->edits = $eng->diff( $from_lines, $to_lines );
}
/**
* @return DiffOp[]
*/
public function getEdits() {
return $this->edits;
}
/**
* Compute reversed Diff.
*
* SYNOPSIS:
*
* $diff = new Diff($lines1, $lines2);
* $rev = $diff->reverse();
*
* @return Object A Diff object representing the inverse of the
* original diff.
*/
public function reverse() {
$rev = $this;
$rev->edits = [];
/** @var DiffOp $edit */
foreach ( $this->edits as $edit ) {
$rev->edits[] = $edit->reverse();
}
return $rev;
}
/**
* Check for empty diff.
*
* @return bool True if two sequences were identical.
*/
public function isEmpty() {
foreach ( $this->edits as $edit ) {
if ( $edit->type != 'copy' ) {
return false;
}
}
return true;
}
/**
* Compute the length of the Longest Common Subsequence (LCS).
*
* This is mostly for diagnostic purposed.
*
* @return int The length of the LCS.
*/
public function lcs() {
$lcs = 0;
foreach ( $this->edits as $edit ) {
if ( $edit->type == 'copy' ) {
$lcs += count( $edit->orig );
}
}
return $lcs;
}
/**
* Get the original set of lines.
*
* This reconstructs the $from_lines parameter passed to the
* constructor.
*
* @return string[] The original sequence of strings.
*/
public function orig() {
$lines = [];
foreach ( $this->edits as $edit ) {
if ( $edit->orig ) {
array_splice( $lines, count( $lines ), 0, $edit->orig );
}
}
return $lines;
}
/**
* Get the closing set of lines.
*
* This reconstructs the $to_lines parameter passed to the
* constructor.
*
* @return string[] The sequence of strings.
*/
public function closing() {
$lines = [];
foreach ( $this->edits as $edit ) {
if ( $edit->closing ) {
array_splice( $lines, count( $lines ), 0, $edit->closing );
}
}
return $lines;
}
}
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