<?php
/**
* Class used internally by Diff to actually compute the diffs.
*
* This class uses the xdiff PECL package (http://pecl.php.net/package/xdiff)
* to compute the differences between the two input arrays.
*
* Copyright 2004-2010 The Horde Project (http://www.horde.org/)
*
* See the enclosed file COPYING for license information (LGPL). If you did
* not receive this file, see http://opensource.org/licenses/lgpl-license.php.
*
* @author Jon Parise <jon@horde.org>
* @package Text_Diff
*/
class Text_Diff_Engine_xdiff {
/**
*/
function diff($from_lines, $to_lines)
{
array_walk($from_lines, array('Text_Diff', 'trimNewlines'));
array_walk($to_lines, array('Text_Diff', 'trimNewlines'));
/* Convert the two input arrays into strings for xdiff processing. */
$from_string = implode("\n", $from_lines);
$to_string = implode("\n", $to_lines);
/* Diff the two strings and convert the result to an array. */
$diff = xdiff_string_diff($from_string, $to_string, count($to_lines));
$diff = explode("\n", $diff);
/* Walk through the diff one line at a time. We build the $edits
* array of diff operations by reading the first character of the
* xdiff output (which is in the "unified diff" format).
*
* Note that we don't have enough information to detect "changed"
* lines using this approach, so we can't add Text_Diff_Op_changed
* instances to the $edits array. The result is still perfectly
* valid, albeit a little less descriptive and efficient. */
$edits = array();
foreach ($diff as $line) {
if (!strlen($line)) {
continue;
}
switch ($line[0]) {
case ' ':
$edits[] = new Text_Diff_Op_copy(array(substr($line, 1)));
break;
case '+':
$edits[] = new Text_Diff_Op_add(array(substr($line, 1)));
break;
case '-':
$edits[] = new Text_Diff_Op_delete(array(substr($line, 1)));
break;
}
}
return $edits;
}
}