Adding upstream version 6.4.3+dfsg1.upstream/6.4.3+dfsg1

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 448 insertions, 0 deletions

diff --git a/wp-includes/Text/Diff/Engine/native.php b/wp-includes/Text/Diff/Engine/native.php
new file mode 100644
index 0000000..b3d8441
--- /dev/null
+++ b/wp-includes/Text/Diff/Engine/native.php
@@ -0,0 +1,448 @@
+<?php
+/**
+ * Class used internally by Text_Diff to actually compute the diffs.
+ *
+ * This class is implemented using native PHP code.
+ *
+ * The algorithm used here is mostly lifted from the perl module
+ * Algorithm::Diff (version 1.06) by Ned Konz, which is available at:
+ * https://cpan.metacpan.org/authors/id/N/NE/NEDKONZ/Algorithm-Diff-1.06.zip
+ *
+ * More ideas are taken from: http://www.ics.uci.edu/~eppstein/161/960229.html
+ *
+ * Some ideas (and a bit of code) are taken from analyze.c, of GNU
+ * diffutils-2.7, which can be found at:
+ * ftp://gnudist.gnu.org/pub/gnu/diffutils/diffutils-2.7.tar.gz
+ *
+ * Some ideas (subdivision by NCHUNKS > 2, and some optimizations) are from
+ * Geoffrey T. Dairiki <dairiki@dairiki.org>. The original PHP version of this
+ * code was written by him, and is used/adapted with his permission.
+ *
+ * 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 https://opensource.org/license/lgpl-2-1/.
+ *
+ * @author  Geoffrey T. Dairiki <dairiki@dairiki.org>
+ * @package Text_Diff
+ */
+class Text_Diff_Engine_native {
+
+    public $xchanged;
+    public $ychanged;
+    public $xv;
+    public $yv;
+    public $xind;
+    public $yind;
+    public $seq;
+    public $in_seq;
+    public $lcs;
+
+    function diff($from_lines, $to_lines)
+    {
+        array_walk($from_lines, array('Text_Diff', 'trimNewlines'));
+        array_walk($to_lines, array('Text_Diff', 'trimNewlines'));
+
+        $n_from = count($from_lines);
+        $n_to = count($to_lines);
+
+        $this->xchanged = $this->ychanged = array();
+        $this->xv = $this->yv = array();
+        $this->xind = $this->yind = array();
+        unset($this->seq);
+        unset($this->in_seq);
+        unset($this->lcs);
+
+        // Skip leading common lines.
+        for ($skip = 0; $skip < $n_from && $skip < $n_to; $skip++) {
+            if ($from_lines[$skip] !== $to_lines[$skip]) {
+                break;
+            }
+            $this->xchanged[$skip] = $this->ychanged[$skip] = false;
+        }
+
+        // Skip trailing common lines.
+        $xi = $n_from; $yi = $n_to;
+        for ($endskip = 0; --$xi > $skip && --$yi > $skip; $endskip++) {
+            if ($from_lines[$xi] !== $to_lines[$yi]) {
+                break;
+            }
+            $this->xchanged[$xi] = $this->ychanged[$yi] = false;
+        }
+
+        // Ignore lines which do not exist in both files.
+        for ($xi = $skip; $xi < $n_from - $endskip; $xi++) {
+            $xhash[$from_lines[$xi]] = 1;
+        }
+        for ($yi = $skip; $yi < $n_to - $endskip; $yi++) {
+            $line = $to_lines[$yi];
+            if (($this->ychanged[$yi] = empty($xhash[$line]))) {
+                continue;
+            }
+            $yhash[$line] = 1;
+            $this->yv[] = $line;
+            $this->yind[] = $yi;
+        }
+        for ($xi = $skip; $xi < $n_from - $endskip; $xi++) {
+            $line = $from_lines[$xi];
+            if (($this->xchanged[$xi] = empty($yhash[$line]))) {
+                continue;
+            }
+            $this->xv[] = $line;
+            $this->xind[] = $xi;
+        }
+
+        // Find the LCS.
+        $this->_compareseq(0, count($this->xv), 0, count($this->yv));
+
+        // Merge edits when possible.
+        $this->_shiftBoundaries($from_lines, $this->xchanged, $this->ychanged);
+        $this->_shiftBoundaries($to_lines, $this->ychanged, $this->xchanged);
+
+        // Compute the edit operations.
+        $edits = array();
+        $xi = $yi = 0;
+        while ($xi < $n_from || $yi < $n_to) {
+            assert($yi < $n_to || $this->xchanged[$xi]);
+            assert($xi < $n_from || $this->ychanged[$yi]);
+
+            // Skip matching "snake".
+            $copy = array();
+            while ($xi < $n_from && $yi < $n_to
+                   && !$this->xchanged[$xi] && !$this->ychanged[$yi]) {
+                $copy[] = $from_lines[$xi++];
+                ++$yi;
+            }
+            if ($copy) {
+                $edits[] = new Text_Diff_Op_copy($copy);
+            }
+
+            // Find deletes & adds.
+            $delete = array();
+            while ($xi < $n_from && $this->xchanged[$xi]) {
+                $delete[] = $from_lines[$xi++];
+            }
+
+            $add = array();
+            while ($yi < $n_to && $this->ychanged[$yi]) {
+                $add[] = $to_lines[$yi++];
+            }
+
+            if ($delete && $add) {
+                $edits[] = new Text_Diff_Op_change($delete, $add);
+            } elseif ($delete) {
+                $edits[] = new Text_Diff_Op_delete($delete);
+            } elseif ($add) {
+                $edits[] = new Text_Diff_Op_add($add);
+            }
+        }
+
+        return $edits;
+    }
+
+    /**
+     * Divides the Largest Common Subsequence (LCS) of the sequences (XOFF,
+     * XLIM) and (YOFF, YLIM) into NCHUNKS approximately equally sized
+     * segments.
+     *
+     * Returns (LCS, PTS).  LCS is the length of the LCS. PTS is an array of
+     * NCHUNKS+1 (X, Y) indexes giving the diving points between sub
+     * sequences.  The first sub-sequence is contained in (X0, X1), (Y0, Y1),
+     * the second in (X1, X2), (Y1, Y2) and so on.  Note that (X0, Y0) ==
+     * (XOFF, YOFF) and (X[NCHUNKS], Y[NCHUNKS]) == (XLIM, YLIM).
+     *
+     * This function assumes that the first lines of the specified portions of
+     * the two files do not match, and likewise that the last lines do not
+     * match.  The caller must trim matching lines from the beginning and end
+     * of the portions it is going to specify.
+     */
+    function _diag ($xoff, $xlim, $yoff, $ylim, $nchunks)
+    {
+        $flip = false;
+
+        if ($xlim - $xoff > $ylim - $yoff) {
+            /* Things seems faster (I'm not sure I understand why) when the
+             * shortest sequence is in X. */
+            $flip = true;
+            list ($xoff, $xlim, $yoff, $ylim)
+                = array($yoff, $ylim, $xoff, $xlim);
+        }
+
+        if ($flip) {
+            for ($i = $ylim - 1; $i >= $yoff; $i--) {
+                $ymatches[$this->xv[$i]][] = $i;
+            }
+        } else {
+            for ($i = $ylim - 1; $i >= $yoff; $i--) {
+                $ymatches[$this->yv[$i]][] = $i;
+            }
+        }
+
+        $this->lcs = 0;
+        $this->seq[0]= $yoff - 1;
+        $this->in_seq = array();
+        $ymids[0] = array();
+
+        $numer = $xlim - $xoff + $nchunks - 1;
+        $x = $xoff;
+        for ($chunk = 0; $chunk < $nchunks; $chunk++) {
+            if ($chunk > 0) {
+                for ($i = 0; $i <= $this->lcs; $i++) {
+                    $ymids[$i][$chunk - 1] = $this->seq[$i];
+                }
+            }
+
+            $x1 = $xoff + (int)(($numer + ($xlim - $xoff) * $chunk) / $nchunks);
+            for (; $x < $x1; $x++) {
+                $line = $flip ? $this->yv[$x] : $this->xv[$x];
+                if (empty($ymatches[$line])) {
+                    continue;
+                }
+                $matches = $ymatches[$line];
+                reset($matches);
+                while ($y = current($matches)) {
+                    if (empty($this->in_seq[$y])) {
+                        $k = $this->_lcsPos($y);
+                        assert($k > 0);
+                        $ymids[$k] = $ymids[$k - 1];
+                        break;
+                    }
+                    next($matches);
+                }
+                while ($y = current($matches)) {
+                    if ($y > $this->seq[$k - 1]) {
+                        assert($y <= $this->seq[$k]);
+                        /* Optimization: this is a common case: next match is
+                         * just replacing previous match. */
+                        $this->in_seq[$this->seq[$k]] = false;
+                        $this->seq[$k] = $y;
+                        $this->in_seq[$y] = 1;
+                    } elseif (empty($this->in_seq[$y])) {
+                        $k = $this->_lcsPos($y);
+                        assert($k > 0);
+                        $ymids[$k] = $ymids[$k - 1];
+                    }
+                    next($matches);
+                }
+            }
+        }
+
+        $seps[] = $flip ? array($yoff, $xoff) : array($xoff, $yoff);
+        $ymid = $ymids[$this->lcs];
+        for ($n = 0; $n < $nchunks - 1; $n++) {
+            $x1 = $xoff + (int)(($numer + ($xlim - $xoff) * $n) / $nchunks);
+            $y1 = $ymid[$n] + 1;
+            $seps[] = $flip ? array($y1, $x1) : array($x1, $y1);
+        }
+        $seps[] = $flip ? array($ylim, $xlim) : array($xlim, $ylim);
+
+        return array($this->lcs, $seps);
+    }
+
+    function _lcsPos($ypos)
+    {
+        $end = $this->lcs;
+        if ($end == 0 || $ypos > $this->seq[$end]) {
+            $this->seq[++$this->lcs] = $ypos;
+            $this->in_seq[$ypos] = 1;
+            return $this->lcs;
+        }
+
+        $beg = 1;
+        while ($beg < $end) {
+            $mid = (int)(($beg + $end) / 2);
+            if ($ypos > $this->seq[$mid]) {
+                $beg = $mid + 1;
+            } else {
+                $end = $mid;
+            }
+        }
+
+        assert($ypos != $this->seq[$end]);
+
+        $this->in_seq[$this->seq[$end]] = false;
+        $this->seq[$end] = $ypos;
+        $this->in_seq[$ypos] = 1;
+        return $end;
+    }
+
+    /**
+     * Finds LCS of two sequences.
+     *
+     * The results are recorded in the vectors $this->{x,y}changed[], by
+     * storing a 1 in the element for each line that is an insertion or
+     * deletion (ie. is not in the LCS).
+     *
+     * The subsequence of file 0 is (XOFF, XLIM) and likewise for file 1.
+     *
+     * Note that XLIM, YLIM are exclusive bounds.  All line numbers are
+     * origin-0 and discarded lines are not counted.
+     */
+    function _compareseq ($xoff, $xlim, $yoff, $ylim)
+    {
+        /* Slide down the bottom initial diagonal. */
+        while ($xoff < $xlim && $yoff < $ylim
+               && $this->xv[$xoff] == $this->yv[$yoff]) {
+            ++$xoff;
+            ++$yoff;
+        }
+
+        /* Slide up the top initial diagonal. */
+        while ($xlim > $xoff && $ylim > $yoff
+               && $this->xv[$xlim - 1] == $this->yv[$ylim - 1]) {
+            --$xlim;
+            --$ylim;
+        }
+
+        if ($xoff == $xlim || $yoff == $ylim) {
+            $lcs = 0;
+        } else {
+            /* This is ad hoc but seems to work well.  $nchunks =
+             * sqrt(min($xlim - $xoff, $ylim - $yoff) / 2.5); $nchunks =
+             * max(2,min(8,(int)$nchunks)); */
+            $nchunks = min(7, $xlim - $xoff, $ylim - $yoff) + 1;
+            list($lcs, $seps)
+                = $this->_diag($xoff, $xlim, $yoff, $ylim, $nchunks);
+        }
+
+        if ($lcs == 0) {
+            /* X and Y sequences have no common subsequence: mark all
+             * changed. */
+            while ($yoff < $ylim) {
+                $this->ychanged[$this->yind[$yoff++]] = 1;
+            }
+            while ($xoff < $xlim) {
+                $this->xchanged[$this->xind[$xoff++]] = 1;
+            }
+        } else {
+            /* Use the partitions to split this problem into subproblems. */
+            reset($seps);
+            $pt1 = $seps[0];
+            while ($pt2 = next($seps)) {
+                $this->_compareseq ($pt1[0], $pt2[0], $pt1[1], $pt2[1]);
+                $pt1 = $pt2;
+            }
+        }
+    }
+
+    /**
+     * Adjusts inserts/deletes of identical lines to join changes as much as
+     * possible.
+     *
+     * We do something when a run of changed lines include a line at one end
+     * and has an excluded, identical line at the other.  We are free to
+     * choose which identical line is included.  `compareseq' usually chooses
+     * the one at the beginning, but usually it is cleaner to consider the
+     * following identical line to be the "change".
+     *
+     * This is extracted verbatim from analyze.c (GNU diffutils-2.7).
+     */
+    function _shiftBoundaries($lines, &$changed, $other_changed)
+    {
+        $i = 0;
+        $j = 0;
+
+        assert(count($lines) == count($changed));
+        $len = count($lines);
+        $other_len = count($other_changed);
+
+        while (1) {
+            /* Scan forward to find the beginning of another run of
+             * changes. Also keep track of the corresponding point in the
+             * other file.
+             *
+             * Throughout this code, $i and $j are adjusted together so that
+             * the first $i elements of $changed and the first $j elements of
+             * $other_changed both contain the same number of zeros (unchanged
+             * lines).
+             *
+             * Furthermore, $j is always kept so that $j == $other_len or
+             * $other_changed[$j] == false. */
+            while ($j < $other_len && $other_changed[$j]) {
+                $j++;
+            }
+
+            while ($i < $len && ! $changed[$i]) {
+                assert($j < $other_len && ! $other_changed[$j]);
+                $i++; $j++;
+                while ($j < $other_len && $other_changed[$j]) {
+                    $j++;
+                }
+            }
+
+            if ($i == $len) {
+                break;
+            }
+
+            $start = $i;
+
+            /* Find the end of this run of changes. */
+            while (++$i < $len && $changed[$i]) {
+                continue;
+            }
+
+            do {
+                /* Record the length of this run of changes, so that we can
+                 * later determine whether the run has grown. */
+                $runlength = $i - $start;
+
+                /* Move the changed region back, so long as the previous
+                 * unchanged line matches the last changed one.  This merges
+                 * with previous changed regions. */
+                while ($start > 0 && $lines[$start - 1] == $lines[$i - 1]) {
+                    $changed[--$start] = 1;
+                    $changed[--$i] = false;
+                    while ($start > 0 && $changed[$start - 1]) {
+                        $start--;
+                    }
+                    assert($j > 0);
+                    while ($other_changed[--$j]) {
+                        continue;
+                    }
+                    assert($j >= 0 && !$other_changed[$j]);
+                }
+
+                /* Set CORRESPONDING to the end of the changed run, at the
+                 * last point where it corresponds to a changed run in the
+                 * other file. CORRESPONDING == LEN means no such point has
+                 * been found. */
+                $corresponding = $j < $other_len ? $i : $len;
+
+                /* Move the changed region forward, so long as the first
+                 * changed line matches the following unchanged one.  This
+                 * merges with following changed regions.  Do this second, so
+                 * that if there are no merges, the changed region is moved
+                 * forward as far as possible. */
+                while ($i < $len && $lines[$start] == $lines[$i]) {
+                    $changed[$start++] = false;
+                    $changed[$i++] = 1;
+                    while ($i < $len && $changed[$i]) {
+                        $i++;
+                    }
+
+                    assert($j < $other_len && ! $other_changed[$j]);
+                    $j++;
+                    if ($j < $other_len && $other_changed[$j]) {
+                        $corresponding = $i;
+                        while ($j < $other_len && $other_changed[$j]) {
+                            $j++;
+                        }
+                    }
+                }
+            } while ($runlength != $i - $start);
+
+            /* If possible, move the fully-merged run of changes back to a
+             * corresponding run in the other file. */
+            while ($corresponding < $i) {
+                $changed[--$start] = 1;
+                $changed[--$i] = 0;
+                assert($j > 0);
+                while ($other_changed[--$j]) {
+                    continue;
+                }
+                assert($j >= 0 && !$other_changed[$j]);
+            }
+        }
+    }
+
+}