tawfekov/ZF2EntityAudit

<?php

/*
    Paul's Simple Diff Algorithm v 0.1
    (C) Paul Butler 2007 <http://www.paulbutler.org/>
    May be used and distributed under the zlib/libpng license.

    This code is intended for learning purposes; it was written with short
    code taking priority over performance. It could be used in a practical
    application, but there are a few ways it could be optimized.

    Given two arrays, the function diff will return an array of the changes.
    I won't describe the format of the array, but it will be obvious
    if you use print_r() on the result of a diff on some test data.

    htmlDiff is a wrapper for the diff command, it takes two strings and
    returns the differences in HTML. The tags used are <ins> and <del>,
    which can easily be styled with CSS.
*/

namespace ZF2EntityAudit\Utils;

/**
 * Class of the SimpleDiff PHP library by Paul Butler
 *
 * @link https://github.com/paulgb/simplediff
 */
class SimpleDiff
{
    public function diff(array $old, array $new)
    {
        $maxlen = 0;
        foreach ($old as $oindex => $ovalue) {
            $nkeys = array_keys($new, $ovalue);
            foreach ($nkeys as $nindex) {
                $matrix[$oindex][$nindex] = isset($matrix[$oindex - 1][$nindex - 1]) ?
                        $matrix[$oindex - 1][$nindex - 1] + 1 : 1;
                if ($matrix[$oindex][$nindex] > $maxlen) {
                    $maxlen = $matrix[$oindex][$nindex];
                    $omax = $oindex + 1 - $maxlen;
                    $nmax = $nindex + 1 - $maxlen;
                }
            }
        }
        if ($maxlen == 0) return array(array('d' => $old, 'i' => $new));
        return array_merge(
            $this->diff(array_slice($old, 0, $omax), array_slice($new, 0, $nmax)),
            array_slice($new, $nmax, $maxlen),
            $this->diff(array_slice($old, $omax + $maxlen), array_slice($new, $nmax + $maxlen)));
    }

    public function htmlDiff($old, $new)
    {
        $ret = '';
        $diff = $this->diff(explode(' ', $old), explode(' ', $new));
        foreach ($diff as $k) {
            if (is_array($k))
                $ret .= (!empty($k['d']) ? "<del>" . implode(' ', $k['d']) . "</del> " : '') .
                        (!empty($k['i']) ? "<ins>" . implode(' ', $k['i']) . "</ins> " : '');
            else $ret .= $k . ' ';
        }

        return $ret;
    }
}