| 1 | <?php
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| 2 | /**
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| 3 | *
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| 4 | * @package diff
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| 5 | * @version $Id$
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| 6 | * @copyright (c) 2006 phpBB Group
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| 7 | * @license http://opensource.org/licenses/gpl-license.php GNU Public License
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| 8 | *
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| 9 | */
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| 10 |
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| 11 | /**
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| 12 | * @ignore
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| 13 | */
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| 14 | if (!defined('IN_PHPBB'))
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| 15 | {
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| 16 | exit;
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| 17 | }
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| 18 |
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| 19 | /**
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| 20 | * Code from pear.php.net, Text_Diff-1.1.0 package
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| 21 | * http://pear.php.net/package/Text_Diff/ (native engine)
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| 22 | *
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| 23 | * Modified by phpBB Group to meet our coding standards
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| 24 | * and being able to integrate into phpBB
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| 25 | *
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| 26 | * Class used internally by Text_Diff to actually compute the diffs. This
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| 27 | * class is implemented using native PHP code.
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| 28 | *
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| 29 | * The algorithm used here is mostly lifted from the perl module
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| 30 | * Algorithm::Diff (version 1.06) by Ned Konz, which is available at:
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| 31 | * http://www.perl.com/CPAN/authors/id/N/NE/NEDKONZ/Algorithm-Diff-1.06.zip
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| 32 | *
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| 33 | * More ideas are taken from: http://www.ics.uci.edu/~eppstein/161/960229.html
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| 34 | *
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| 35 | * Some ideas (and a bit of code) are taken from analyze.c, of GNU
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| 36 | * diffutils-2.7, which can be found at:
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| 37 | * ftp://gnudist.gnu.org/pub/gnu/diffutils/diffutils-2.7.tar.gz
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| 38 | *
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| 39 | * Some ideas (subdivision by NCHUNKS > 2, and some optimizations) are from
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| 40 | * Geoffrey T. Dairiki <dairiki@dairiki.org>. The original PHP version of this
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| 41 | * code was written by him, and is used/adapted with his permission.
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| 42 | *
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| 43 | * Copyright 2004-2008 The Horde Project (http://www.horde.org/)
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| 44 | *
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| 45 | * @author Geoffrey T. Dairiki <dairiki@dairiki.org>
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| 46 | * @package diff
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| 47 | *
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| 48 | * @access private
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| 49 | */
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| 50 | class diff_engine
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| 51 | {
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| 52 | /**
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| 53 | * If set to true we trim all lines before we compare them. This ensures that sole space/tab changes do not trigger diffs.
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| 54 | */
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| 55 | var $skip_whitespace_changes = true;
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| 56 |
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| 57 | function diff(&$from_lines, &$to_lines, $preserve_cr = true)
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| 58 | {
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| 59 | // Remove empty lines...
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| 60 | // If preserve_cr is true, we basically only change \r\n and bare \r to \n to get the same carriage returns for both files
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| 61 | // If it is false, we try to only use \n once per line and ommit all empty lines to be able to get a proper data diff
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| 62 |
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| 63 | if (is_array($from_lines))
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| 64 | {
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| 65 | $from_lines = implode("\n", $from_lines);
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| 66 | }
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| 67 |
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| 68 | if (is_array($to_lines))
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| 69 | {
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| 70 | $to_lines = implode("\n", $to_lines);
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| 71 | }
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| 72 |
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| 73 | if ($preserve_cr)
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| 74 | {
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| 75 | $from_lines = explode("\n", str_replace("\r", "\n", str_replace("\r\n", "\n", $from_lines)));
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| 76 | $to_lines = explode("\n", str_replace("\r", "\n", str_replace("\r\n", "\n", $to_lines)));
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| 77 | }
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| 78 | else
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| 79 | {
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| 80 | $from_lines = explode("\n", preg_replace('#[\n\r]+#', "\n", $from_lines));
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| 81 | $to_lines = explode("\n", preg_replace('#[\n\r]+#', "\n", $to_lines));
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| 82 | }
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| 83 |
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| 84 | $n_from = sizeof($from_lines);
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| 85 | $n_to = sizeof($to_lines);
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| 86 |
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| 87 | $this->xchanged = $this->ychanged = $this->xv = $this->yv = $this->xind = $this->yind = array();
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| 88 | unset($this->seq, $this->in_seq, $this->lcs);
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| 89 |
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| 90 | // Skip leading common lines.
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| 91 | for ($skip = 0; $skip < $n_from && $skip < $n_to; $skip++)
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| 92 | {
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| 93 | if (trim($from_lines[$skip]) !== trim($to_lines[$skip]))
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| 94 | {
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| 95 | break;
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| 96 | }
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| 97 | $this->xchanged[$skip] = $this->ychanged[$skip] = false;
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| 98 | }
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| 99 |
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| 100 | // Skip trailing common lines.
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| 101 | $xi = $n_from;
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| 102 | $yi = $n_to;
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| 103 |
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| 104 | for ($endskip = 0; --$xi > $skip && --$yi > $skip; $endskip++)
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| 105 | {
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| 106 | if (trim($from_lines[$xi]) !== trim($to_lines[$yi]))
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| 107 | {
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| 108 | break;
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| 109 | }
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| 110 | $this->xchanged[$xi] = $this->ychanged[$yi] = false;
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| 111 | }
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| 112 |
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| 113 | // Ignore lines which do not exist in both files.
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| 114 | for ($xi = $skip; $xi < $n_from - $endskip; $xi++)
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| 115 | {
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| 116 | if ($this->skip_whitespace_changes) $xhash[trim($from_lines[$xi])] = 1; else $xhash[$from_lines[$xi]] = 1;
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| 117 | }
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| 118 |
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| 119 | for ($yi = $skip; $yi < $n_to - $endskip; $yi++)
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| 120 | {
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| 121 | $line = ($this->skip_whitespace_changes) ? trim($to_lines[$yi]) : $to_lines[$yi];
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| 122 |
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| 123 | if (($this->ychanged[$yi] = empty($xhash[$line])))
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| 124 | {
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| 125 | continue;
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| 126 | }
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| 127 | $yhash[$line] = 1;
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| 128 | $this->yv[] = $line;
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| 129 | $this->yind[] = $yi;
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| 130 | }
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| 131 |
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| 132 | for ($xi = $skip; $xi < $n_from - $endskip; $xi++)
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| 133 | {
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| 134 | $line = ($this->skip_whitespace_changes) ? trim($from_lines[$xi]) : $from_lines[$xi];
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| 135 |
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| 136 | if (($this->xchanged[$xi] = empty($yhash[$line])))
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| 137 | {
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| 138 | continue;
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| 139 | }
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| 140 | $this->xv[] = $line;
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| 141 | $this->xind[] = $xi;
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| 142 | }
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| 143 |
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| 144 | // Find the LCS.
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| 145 | $this->_compareseq(0, sizeof($this->xv), 0, sizeof($this->yv));
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| 146 |
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| 147 | // Merge edits when possible.
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| 148 | if ($this->skip_whitespace_changes)
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| 149 | {
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| 150 | $from_lines_clean = array_map('trim', $from_lines);
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| 151 | $to_lines_clean = array_map('trim', $to_lines);
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| 152 |
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| 153 | $this->_shift_boundaries($from_lines_clean, $this->xchanged, $this->ychanged);
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| 154 | $this->_shift_boundaries($to_lines_clean, $this->ychanged, $this->xchanged);
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| 155 |
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| 156 | unset($from_lines_clean, $to_lines_clean);
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| 157 | }
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| 158 | else
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| 159 | {
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| 160 | $this->_shift_boundaries($from_lines, $this->xchanged, $this->ychanged);
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| 161 | $this->_shift_boundaries($to_lines, $this->ychanged, $this->xchanged);
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| 162 | }
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| 163 |
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| 164 | // Compute the edit operations.
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| 165 | $edits = array();
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| 166 | $xi = $yi = 0;
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| 167 |
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| 168 | while ($xi < $n_from || $yi < $n_to)
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| 169 | {
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| 170 | // Skip matching "snake".
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| 171 | $copy = array();
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| 172 |
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| 173 | while ($xi < $n_from && $yi < $n_to && !$this->xchanged[$xi] && !$this->ychanged[$yi])
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| 174 | {
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| 175 | $copy[] = $from_lines[$xi++];
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| 176 | $yi++;
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| 177 | }
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| 178 |
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| 179 | if ($copy)
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| 180 | {
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| 181 | $edits[] = new diff_op_copy($copy);
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| 182 | }
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| 183 |
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| 184 | // Find deletes & adds.
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| 185 | $delete = array();
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| 186 | while ($xi < $n_from && $this->xchanged[$xi])
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| 187 | {
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| 188 | $delete[] = $from_lines[$xi++];
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| 189 | }
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| 190 |
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| 191 | $add = array();
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| 192 | while ($yi < $n_to && $this->ychanged[$yi])
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| 193 | {
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| 194 | $add[] = $to_lines[$yi++];
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| 195 | }
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| 196 |
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| 197 | if ($delete && $add)
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| 198 | {
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| 199 | $edits[] = new diff_op_change($delete, $add);
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| 200 | }
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| 201 | else if ($delete)
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| 202 | {
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| 203 | $edits[] = new diff_op_delete($delete);
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| 204 | }
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| 205 | else if ($add)
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| 206 | {
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| 207 | $edits[] = new diff_op_add($add);
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| 208 | }
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| 209 | }
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| 210 |
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| 211 | return $edits;
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| 212 | }
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| 213 |
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| 214 | /**
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| 215 | * Divides the Largest Common Subsequence (LCS) of the sequences (XOFF,
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| 216 | * XLIM) and (YOFF, YLIM) into NCHUNKS approximately equally sized segments.
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| 217 | *
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| 218 | * Returns (LCS, PTS). LCS is the length of the LCS. PTS is an array of
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| 219 | * NCHUNKS+1 (X, Y) indexes giving the diving points between sub
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| 220 | * sequences. The first sub-sequence is contained in (X0, X1), (Y0, Y1),
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| 221 | * the second in (X1, X2), (Y1, Y2) and so on. Note that (X0, Y0) ==
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| 222 | * (XOFF, YOFF) and (X[NCHUNKS], Y[NCHUNKS]) == (XLIM, YLIM).
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| 223 | *
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| 224 | * This function assumes that the first lines of the specified portions of
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| 225 | * the two files do not match, and likewise that the last lines do not
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| 226 | * match. The caller must trim matching lines from the beginning and end
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| 227 | * of the portions it is going to specify.
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| 228 | */
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| 229 | function _diag($xoff, $xlim, $yoff, $ylim, $nchunks)
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| 230 | {
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| 231 | $flip = false;
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| 232 |
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| 233 | if ($xlim - $xoff > $ylim - $yoff)
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| 234 | {
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| 235 | // Things seems faster (I'm not sure I understand why) when the shortest sequence is in X.
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| 236 | $flip = true;
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| 237 | list($xoff, $xlim, $yoff, $ylim) = array($yoff, $ylim, $xoff, $xlim);
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| 238 | }
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| 239 |
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| 240 | if ($flip)
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| 241 | {
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| 242 | for ($i = $ylim - 1; $i >= $yoff; $i--)
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| 243 | {
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| 244 | $ymatches[$this->xv[$i]][] = $i;
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| 245 | }
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| 246 | }
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| 247 | else
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| 248 | {
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| 249 | for ($i = $ylim - 1; $i >= $yoff; $i--)
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| 250 | {
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| 251 | $ymatches[$this->yv[$i]][] = $i;
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| 252 | }
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| 253 | }
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| 254 |
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| 255 | $this->lcs = 0;
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| 256 | $this->seq[0]= $yoff - 1;
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| 257 | $this->in_seq = array();
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| 258 | $ymids[0] = array();
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| 259 |
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| 260 | $numer = $xlim - $xoff + $nchunks - 1;
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| 261 | $x = $xoff;
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| 262 |
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| 263 | for ($chunk = 0; $chunk < $nchunks; $chunk++)
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| 264 | {
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| 265 | if ($chunk > 0)
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| 266 | {
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| 267 | for ($i = 0; $i <= $this->lcs; $i++)
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| 268 | {
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| 269 | $ymids[$i][$chunk - 1] = $this->seq[$i];
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| 270 | }
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| 271 | }
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| 272 |
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| 273 | $x1 = $xoff + (int)(($numer + ($xlim - $xoff) * $chunk) / $nchunks);
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| 274 |
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| 275 | for (; $x < $x1; $x++)
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| 276 | {
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| 277 | $line = $flip ? $this->yv[$x] : $this->xv[$x];
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| 278 | if (empty($ymatches[$line]))
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| 279 | {
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| 280 | continue;
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| 281 | }
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| 282 | $matches = $ymatches[$line];
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| 283 |
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| 284 | reset($matches);
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| 285 | while (list(, $y) = each($matches))
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| 286 | {
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| 287 | if (empty($this->in_seq[$y]))
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| 288 | {
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| 289 | $k = $this->_lcs_pos($y);
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| 290 | $ymids[$k] = $ymids[$k - 1];
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| 291 | break;
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| 292 | }
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| 293 | }
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| 294 |
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| 295 | // no reset() here
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| 296 | while (list(, $y) = each($matches))
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| 297 | {
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| 298 | if ($y > $this->seq[$k - 1])
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| 299 | {
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| 300 | // Optimization: this is a common case: next match is just replacing previous match.
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| 301 | $this->in_seq[$this->seq[$k]] = false;
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| 302 | $this->seq[$k] = $y;
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| 303 | $this->in_seq[$y] = 1;
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| 304 | }
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| 305 | else if (empty($this->in_seq[$y]))
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| 306 | {
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| 307 | $k = $this->_lcs_pos($y);
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| 308 | $ymids[$k] = $ymids[$k - 1];
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| 309 | }
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| 310 | }
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| 311 | }
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| 312 | }
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| 313 |
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| 314 | $seps[] = $flip ? array($yoff, $xoff) : array($xoff, $yoff);
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| 315 | $ymid = $ymids[$this->lcs];
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| 316 |
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| 317 | for ($n = 0; $n < $nchunks - 1; $n++)
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| 318 | {
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| 319 | $x1 = $xoff + (int)(($numer + ($xlim - $xoff) * $n) / $nchunks);
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| 320 | $y1 = $ymid[$n] + 1;
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| 321 | $seps[] = $flip ? array($y1, $x1) : array($x1, $y1);
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| 322 | }
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| 323 | $seps[] = $flip ? array($ylim, $xlim) : array($xlim, $ylim);
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| 324 |
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| 325 | return array($this->lcs, $seps);
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| 326 | }
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| 327 |
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| 328 | function _lcs_pos($ypos)
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| 329 | {
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| 330 | $end = $this->lcs;
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| 331 |
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| 332 | if ($end == 0 || $ypos > $this->seq[$end])
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| 333 | {
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| 334 | $this->seq[++$this->lcs] = $ypos;
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| 335 | $this->in_seq[$ypos] = 1;
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| 336 | return $this->lcs;
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| 337 | }
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| 338 |
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| 339 | $beg = 1;
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| 340 | while ($beg < $end)
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| 341 | {
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| 342 | $mid = (int)(($beg + $end) / 2);
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| 343 | if ($ypos > $this->seq[$mid])
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| 344 | {
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| 345 | $beg = $mid + 1;
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| 346 | }
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| 347 | else
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| 348 | {
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| 349 | $end = $mid;
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| 350 | }
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| 351 | }
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| 352 |
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| 353 | $this->in_seq[$this->seq[$end]] = false;
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| 354 | $this->seq[$end] = $ypos;
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| 355 | $this->in_seq[$ypos] = 1;
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| 356 |
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| 357 | return $end;
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| 358 | }
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| 359 |
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| 360 | /**
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| 361 | * Finds LCS of two sequences.
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| 362 | *
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| 363 | * The results are recorded in the vectors $this->{x,y}changed[], by
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| 364 | * storing a 1 in the element for each line that is an insertion or
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| 365 | * deletion (ie. is not in the LCS).
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| 366 | *
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| 367 | * The subsequence of file 0 is (XOFF, XLIM) and likewise for file 1.
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| 368 | *
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| 369 | * Note that XLIM, YLIM are exclusive bounds. All line numbers are
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| 370 | * origin-0 and discarded lines are not counted.
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| 371 | */
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| 372 | function _compareseq($xoff, $xlim, $yoff, $ylim)
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| 373 | {
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| 374 | // Slide down the bottom initial diagonal.
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| 375 | while ($xoff < $xlim && $yoff < $ylim && $this->xv[$xoff] == $this->yv[$yoff])
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| 376 | {
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| 377 | ++$xoff;
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| 378 | ++$yoff;
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| 379 | }
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| 380 |
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| 381 | // Slide up the top initial diagonal.
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| 382 | while ($xlim > $xoff && $ylim > $yoff && $this->xv[$xlim - 1] == $this->yv[$ylim - 1])
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| 383 | {
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| 384 | --$xlim;
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| 385 | --$ylim;
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| 386 | }
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| 387 |
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| 388 | if ($xoff == $xlim || $yoff == $ylim)
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| 389 | {
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| 390 | $lcs = 0;
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| 391 | }
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| 392 | else
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| 393 | {
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| 394 | // This is ad hoc but seems to work well.
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| 395 | // $nchunks = sqrt(min($xlim - $xoff, $ylim - $yoff) / 2.5);
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| 396 | // $nchunks = max(2,min(8,(int)$nchunks));
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| 397 | $nchunks = min(7, $xlim - $xoff, $ylim - $yoff) + 1;
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| 398 | list($lcs, $seps) = $this->_diag($xoff, $xlim, $yoff, $ylim, $nchunks);
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| 399 | }
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| 400 |
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| 401 | if ($lcs == 0)
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| 402 | {
|
|---|
| 403 | // X and Y sequences have no common subsequence: mark all changed.
|
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| 404 | while ($yoff < $ylim)
|
|---|
| 405 | {
|
|---|
| 406 | $this->ychanged[$this->yind[$yoff++]] = 1;
|
|---|
| 407 | }
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|---|
| 408 |
|
|---|
| 409 | while ($xoff < $xlim)
|
|---|
| 410 | {
|
|---|
| 411 | $this->xchanged[$this->xind[$xoff++]] = 1;
|
|---|
| 412 | }
|
|---|
| 413 | }
|
|---|
| 414 | else
|
|---|
| 415 | {
|
|---|
| 416 | // Use the partitions to split this problem into subproblems.
|
|---|
| 417 | reset($seps);
|
|---|
| 418 | $pt1 = $seps[0];
|
|---|
| 419 |
|
|---|
| 420 | while ($pt2 = next($seps))
|
|---|
| 421 | {
|
|---|
| 422 | $this->_compareseq($pt1[0], $pt2[0], $pt1[1], $pt2[1]);
|
|---|
| 423 | $pt1 = $pt2;
|
|---|
| 424 | }
|
|---|
| 425 | }
|
|---|
| 426 | }
|
|---|
| 427 |
|
|---|
| 428 | /**
|
|---|
| 429 | * Adjusts inserts/deletes of identical lines to join changes as much as possible.
|
|---|
| 430 | *
|
|---|
| 431 | * We do something when a run of changed lines include a line at one end
|
|---|
| 432 | * and has an excluded, identical line at the other. We are free to
|
|---|
| 433 | * choose which identical line is included. 'compareseq' usually chooses
|
|---|
| 434 | * the one at the beginning, but usually it is cleaner to consider the
|
|---|
| 435 | * following identical line to be the "change".
|
|---|
| 436 | *
|
|---|
| 437 | * This is extracted verbatim from analyze.c (GNU diffutils-2.7).
|
|---|
| 438 | */
|
|---|
| 439 | function _shift_boundaries($lines, &$changed, $other_changed)
|
|---|
| 440 | {
|
|---|
| 441 | $i = 0;
|
|---|
| 442 | $j = 0;
|
|---|
| 443 |
|
|---|
| 444 | $len = sizeof($lines);
|
|---|
| 445 | $other_len = sizeof($other_changed);
|
|---|
| 446 |
|
|---|
| 447 | while (1)
|
|---|
| 448 | {
|
|---|
| 449 | // Scan forward to find the beginning of another run of
|
|---|
| 450 | // changes. Also keep track of the corresponding point in the other file.
|
|---|
| 451 | //
|
|---|
| 452 | // Throughout this code, $i and $j are adjusted together so that
|
|---|
| 453 | // the first $i elements of $changed and the first $j elements of
|
|---|
| 454 | // $other_changed both contain the same number of zeros (unchanged lines).
|
|---|
| 455 | //
|
|---|
| 456 | // Furthermore, $j is always kept so that $j == $other_len or $other_changed[$j] == false.
|
|---|
| 457 | while ($j < $other_len && $other_changed[$j])
|
|---|
| 458 | {
|
|---|
| 459 | $j++;
|
|---|
| 460 | }
|
|---|
| 461 |
|
|---|
| 462 | while ($i < $len && ! $changed[$i])
|
|---|
| 463 | {
|
|---|
| 464 | $i++;
|
|---|
| 465 | $j++;
|
|---|
| 466 |
|
|---|
| 467 | while ($j < $other_len && $other_changed[$j])
|
|---|
| 468 | {
|
|---|
| 469 | $j++;
|
|---|
| 470 | }
|
|---|
| 471 | }
|
|---|
| 472 |
|
|---|
| 473 | if ($i == $len)
|
|---|
| 474 | {
|
|---|
| 475 | break;
|
|---|
| 476 | }
|
|---|
| 477 |
|
|---|
| 478 | $start = $i;
|
|---|
| 479 |
|
|---|
| 480 | // Find the end of this run of changes.
|
|---|
| 481 | while (++$i < $len && $changed[$i])
|
|---|
| 482 | {
|
|---|
| 483 | continue;
|
|---|
| 484 | }
|
|---|
| 485 |
|
|---|
| 486 | do
|
|---|
| 487 | {
|
|---|
| 488 | // Record the length of this run of changes, so that we can later determine whether the run has grown.
|
|---|
| 489 | $runlength = $i - $start;
|
|---|
| 490 |
|
|---|
| 491 | // Move the changed region back, so long as the previous unchanged line matches the last changed one.
|
|---|
| 492 | // This merges with previous changed regions.
|
|---|
| 493 | while ($start > 0 && $lines[$start - 1] == $lines[$i - 1])
|
|---|
| 494 | {
|
|---|
| 495 | $changed[--$start] = 1;
|
|---|
| 496 | $changed[--$i] = false;
|
|---|
| 497 |
|
|---|
| 498 | while ($start > 0 && $changed[$start - 1])
|
|---|
| 499 | {
|
|---|
| 500 | $start--;
|
|---|
| 501 | }
|
|---|
| 502 |
|
|---|
| 503 | while ($other_changed[--$j])
|
|---|
| 504 | {
|
|---|
| 505 | continue;
|
|---|
| 506 | }
|
|---|
| 507 | }
|
|---|
| 508 |
|
|---|
| 509 | // Set CORRESPONDING to the end of the changed run, at the last point where it corresponds to a changed run in the
|
|---|
| 510 | // other file. CORRESPONDING == LEN means no such point has been found.
|
|---|
| 511 | $corresponding = $j < $other_len ? $i : $len;
|
|---|
| 512 |
|
|---|
| 513 | // Move the changed region forward, so long as the first changed line matches the following unchanged one.
|
|---|
| 514 | // This merges with following changed regions.
|
|---|
| 515 | // Do this second, so that if there are no merges, the changed region is moved forward as far as possible.
|
|---|
| 516 | while ($i < $len && $lines[$start] == $lines[$i])
|
|---|
| 517 | {
|
|---|
| 518 | $changed[$start++] = false;
|
|---|
| 519 | $changed[$i++] = 1;
|
|---|
| 520 |
|
|---|
| 521 | while ($i < $len && $changed[$i])
|
|---|
| 522 | {
|
|---|
| 523 | $i++;
|
|---|
| 524 | }
|
|---|
| 525 |
|
|---|
| 526 | $j++;
|
|---|
| 527 | if ($j < $other_len && $other_changed[$j])
|
|---|
| 528 | {
|
|---|
| 529 | $corresponding = $i;
|
|---|
| 530 | while ($j < $other_len && $other_changed[$j])
|
|---|
| 531 | {
|
|---|
| 532 | $j++;
|
|---|
| 533 | }
|
|---|
| 534 | }
|
|---|
| 535 | }
|
|---|
| 536 | }
|
|---|
| 537 | while ($runlength != $i - $start);
|
|---|
| 538 |
|
|---|
| 539 | // If possible, move the fully-merged run of changes back to a corresponding run in the other file.
|
|---|
| 540 | while ($corresponding < $i)
|
|---|
| 541 | {
|
|---|
| 542 | $changed[--$start] = 1;
|
|---|
| 543 | $changed[--$i] = 0;
|
|---|
| 544 |
|
|---|
| 545 | while ($other_changed[--$j])
|
|---|
| 546 | {
|
|---|
| 547 | continue;
|
|---|
| 548 | }
|
|---|
| 549 | }
|
|---|
| 550 | }
|
|---|
| 551 | }
|
|---|
| 552 | }
|
|---|
| 553 |
|
|---|
| 554 | ?>
|
|---|
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