Subversion Repositories Applications.papyrus

<div class="page">

<?php

if ($this->HasAccess("read"))

{

/* A php wdiff  (word diff) for wakka, adapted by David Delon

   based on wdiff and phpwiki diff (copyright below).

   TODO : Since wdiff use only directive lines, all stuff in diff class

   related to line and context display should be removed.

   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, or (at your option)

   any later version. */

/* A PHP diff engine for phpwiki.

   Copyright (C) 2000, 2001 Geoffrey T. Dairiki <dairiki@dairiki.org>

   You may copy this code freely under the conditions of the GPL.

*/

/* wdiff -- front end to diff for comparing on a word per word basis.

   Copyright (C) 1992 Free Software Foundation, Inc.

   Francois Pinard <pinard@iro.umontreal.ca>.

   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, or (at your option)

   any later version.

 */

// If asked, call original diff

	if ($_REQUEST["fastdiff"]) {

		/* NOTE: This is a really cheap way to do it. I think it may be more intelligent to write the two pages to temporary files and run /usr/bin/diff over them. Then again, maybe not.        */

		// load pages

		  $pageA = $this->LoadPageById($_REQUEST["a"]);

		  $pageB = $this->LoadPageById($_REQUEST["b"]);

		// prepare bodies

		  $bodyA = explode("\n", $pageA["body"]);

		  $bodyB = explode("\n", $pageB["body"]);

		  $added = array_diff($bodyA, $bodyB);

		  $deleted = array_diff($bodyB, $bodyA);

		  $output .= "<b>Comparaison de <a href=\"".$this->href("", "", "time=".urlencode($pageA["time"]))."\">".$pageA["time"]."</a> à <a href=\"".$this->href("", "", "time=".urlencode($pageB["time"]))."\">".$pageB["time"]."</a></b><br />\n";

		  if ($added)

		  {

			// remove blank lines

			$output .= "<br />\n<b>Additions:</b><br />\n";

			$output .= "<div class=\"additions\">".$this->Format(implode("\n", $added))."</div>";

		  }

		  if ($deleted)

		  {

			$output .= "<br />\n<b>Deletions:</b><br />\n";

			$output .= "<div class=\"deletions\">".$this->Format(implode("\n", $deleted))."</div>";

		  }

		  if (!$added && !$deleted)

		  {

			$output .= "<br />\nNo differences.";

		  }

		  print($output);

	}

	else {

	// load pages

		$pageA = $this->LoadPageById($_REQUEST["b"]);

		$pageB = $this->LoadPageById($_REQUEST["a"]);

		// extract text from bodies

		$textA = $pageA["body"];

		$textB = $pageB["body"];

		$sideA = new Side($textA);

		$sideB = new Side($textB);

		$bodyA='';

		$sideA->split_file_into_words($bodyA);

		$bodyB='';

		$sideB->split_file_into_words($bodyB);

		// diff on these two file

		$diff = new Diff(split("\n",$bodyA),split("\n",$bodyB));

		// format output

		$fmt = new DiffFormatter();

		$sideO = new Side($fmt->format($diff));

		$resync_left=0;

		$resync_right=0;

		$count_total_right=$sideB->getposition() ;

		$sideA->init();

		$sideB->init();

		$output='';

		  while (1) {

		      $sideO->skip_line();

		      if ($sideO->isend()) {

			  break;

		      }

		      if ($sideO->decode_directive_line()) {

			$argument=$sideO->getargument();

			$letter=$sideO->getdirective();

		      switch ($letter) {

			    case 'a':

			      $resync_left = $argument[0];

			      $resync_right = $argument[2] - 1;

			      break;

			    case 'd':

			      $resync_left = $argument[0] - 1;

			      $resync_right = $argument[2];

			      break;

			    case 'c':

			      $resync_left = $argument[0] - 1;

			      $resync_right = $argument[2] - 1;

			      break;

			    }

			    $sideA->skip_until_ordinal($resync_left);

			    $sideB->copy_until_ordinal($resync_right,$output);

	// deleted word

			    if (($letter=='d') || ($letter=='c')) {

			      $sideA->copy_whitespace($output);

			      $output .="@@";

			      $sideA->copy_word($output);

			      $sideA->copy_until_ordinal($argument[1],$output);

			      $output .="@@";

			    }

	// inserted word

			    if ($letter == 'a' || $letter == 'c') {

				$sideB->copy_whitespace($output);

				$output .="££";

				$sideB->copy_word($output);

				$sideB->copy_until_ordinal($argument[3],$output);

				$output .="££";

			    }

		  }

		}

		  $sideB->copy_until_ordinal($count_total_right,$output);

		  $sideB->copy_whitespace($output);

		  $out=$this->Format($output);

		  print $out;

	}

}

else{

	print("<i>Vous n'etes pas autoris&eacute; &agrave; lire cette page.</i>");

}

	// Side : a string for wdiff

	class Side {

	    var $position;

	    var $cursor;

	    var $content;

	    var $character;

	    var $directive;

	    var $argument;

	    var $length;

	    function Side($content) {

	       $this->content=$content;

	       $this->position=0;

	       $this->cursor=0;

	       $this->directive='';

	       $this->argument=array();

	       $this->length=strlen($this->content);

	       $this->character=substr($this->content,0,1);

	    }

	    function getposition() {

	       return $this->position;

	    }

	    function getcharacter() {

	       return $this->character;

	    }

	    function getdirective() {

	       return $this->directive;

	    }

	    function getargument() {

	       return $this->argument;

	    }

	    function nextchar() {

	       $this->cursor++;

	       $this->character=substr($this->content,$this->cursor,1);

	    }

	    function copy_until_ordinal($ordinal,&$out)  {

	       while ($this->position < $ordinal) {

		  $this->copy_whitespace($out);

		  $this->copy_word($out);

	       }

	    }

	    function skip_until_ordinal($ordinal) {

	       while ($this->position < $ordinal) {

		  $this->skip_whitespace();

		  $this->skip_word();

	       }

	    }

	    function split_file_into_words (&$out) {

	       while (!$this->isend()) {

		 $this->skip_whitespace();

		 if ($this->isend()) {

		   break;

		 }

		 $this->copy_word($out);

		 $out .="\n";

	       }

	    }

	    function init() {

	       $this->position=0;

	       $this->cursor=0;

	       $this->directive='';

	       $this->argument=array();

	       $this->character=substr($this->content,0,1);

	    }

	    function isspace($char) {

	       if (ereg('[[:space:]]',$char)) {

		  return true;

	       }

	       else {

		  return false;

	       }

	    }

	    function isdigit($char) {

	       if (ereg('[[:digit:]]',$char)) {

		  return true;

	       }

	       else {

		  return false;

	       }

	    }

	    function isend() {

	       if (($this->cursor)>=($this->length)) {

		  return true;

	       }

	       else {

		  return false;

	       }

	    }

	    function copy_whitespace(&$out)  {

		 while (!$this->isend() && $this->isspace($this->character)) {

		    $out .=$this->character;

		    $this->nextchar();

		 }

	    }

	    function skip_whitespace()  {

		 while (!$this->isend() && $this->isspace($this->character)) {

		    $this->nextchar();

		 }

	    }

	    function skip_line()  {

	      while (!$this->isend() && !$this->isdigit($this->character)) {

		  while (!$this->isend() && $this->character!="\n")

		  $this->nextchar();

		  if($this->character=="\n")

		      $this->nextchar();

	       }

	     }

	     function copy_word(&$out) {

		 while (!$this->isend() && !($this->isspace($this->character))) {

		    $out.=$this->character;

		    $this->nextchar();

		 }

		 $this->position++;

	     }

	     function skip_word() {

		 while (!$this->isend() && !($this->isspace($this->character))) {

		    $this->nextchar();

		 }

		 $this->position++;

	     }

	 function decode_directive_line() {

	  $value=0;

	  $state=0;

	  $error=0;

	  while (!$error && $state < 4) {

	      if ($this->isdigit($this->character)) {

		  $value = 0;

		  while($this->isdigit($this->character)) {

		      $value = 10 * $value + $this->character - '0';

		      $this->nextchar();

		  }

	      }

	      else if ($state != 1 && $state != 3)

	      $error = 1;

	      /* Assign the proper value.  */

	      $this->argument[$state] = $value;

	      /* Skip the following character.  */

	      switch ($state) {

		case 0:

		case 2:

		  if ($this->character == ',')

		     $this->nextchar();

		  break;

		case 1:

		  if ($this->character == 'a' || $this->character == 'd' || $this->character == 'c') {

		      $this->directive = $this->character;

		      $this->nextchar();

		    }

		  else

		    $error = 1;

		  break;

		  case 3:

		  if ($this->character != "\n")

		    $error = 1;

		    break;

		  }

		 $state++;

	      }

	  /* Complete reading of the line and return success value.  */

	  while ((!$this->isend()) && ($this->character != "\n")) {

	      $this->nextchar();

	  }

	  if ($this->character == "\n")

	      $this->nextchar();

	  return !$error;

	}

	}

	// difflib

	//

	// A PHP diff engine for phpwiki.

	//

	// Copyright (C) 2000, 2001 Geoffrey T. Dairiki <dairiki@dairiki.org>

	// You may copy this code freely under the conditions of the GPL.

	//

	// PHP3 does not have assert()

	define('USE_ASSERTS', function_exists('assert'));

	class _DiffOp {

	    var $type;

	    var $orig;

	    var $final;

	    function norig() {

		return $this->orig ? sizeof($this->orig) : 0;

	    }

	    function nfinal() {

		return $this->final ? sizeof($this->final) : 0;

	    }

	}

	class _DiffOp_Copy extends _DiffOp {

	    var $type = 'copy';

	    function _DiffOp_Copy ($orig, $final = false) {

		if (!is_array($final))

		    $final = $orig;

		$this->orig = $orig;

		$this->final = $final;

	    }

	}

	class _DiffOp_Delete extends _DiffOp {

	    var $type = 'delete';

	    function _DiffOp_Delete ($lines) {

		$this->orig = $lines;

		$this->final = false;

	    }

	}

	class _DiffOp_Add extends _DiffOp {

	    var $type = 'add';

	    function _DiffOp_Add ($lines) {

		$this->final = $lines;

		$this->orig = false;

	    }

	}

	class _DiffOp_Change extends _DiffOp {

	    var $type = 'change';

	    function _DiffOp_Change ($orig, $final) {

		$this->orig = $orig;

		$this->final = $final;

	    }

	}

	/**

	 * Class used internally by Diff to actually compute the diffs.

	 *

	 * The algorithm used here is mostly lifted from the perl module

	 * Algorithm::Diff (version 1.06) by Ned Konz, which is available at:

	 *   http://www.perl.com/CPAN/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 are (and a bit of code) are from from analyze.c, from GNU

	 * diffutils-2.7, which can be found at:

	 *   ftp://gnudist.gnu.org/pub/gnu/diffutils/diffutils-2.7.tar.gz

	 *

	 * Finally, some ideas (subdivision by NCHUNKS > 2, and some optimizations)

	 * are my own.

	 *

	 * @author Geoffrey T. Dairiki

	 * @access private

	 */

	class _DiffEngine

	{

	    function diff ($from_lines, $to_lines) {

		$n_from = sizeof($from_lines);

		$n_to = sizeof($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.

		$this->_compareseq(0, sizeof($this->xv), 0, sizeof($this->yv));

		// Merge edits when possible

		$this->_shift_boundaries($from_lines, $this->xchanged, $this->ychanged);

		$this->_shift_boundaries($to_lines, $this->ychanged, $this->xchanged);

		// Compute the edit operations.

		$edits = array();

		$xi = $yi = 0;

		while ($xi < $n_from || $yi < $n_to) {

		    USE_ASSERTS && assert($yi < $n_to || $this->xchanged[$xi]);

		    USE_ASSERTS && 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)

			$edits[] = new _DiffOp_Copy($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)

			$edits[] = new _DiffOp_Change($delete, $add);

		    elseif ($delete)

			$edits[] = new _DiffOp_Delete($delete);

		    elseif ($add)

			$edits[] = new _DiffOp_Add($add);

		}

		return $edits;

	    }

	    /* Divide 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 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 (list ($junk, $y) = each($matches))

			    if (empty($this->in_seq[$y])) {

				$k = $this->_lcs_pos($y);

				USE_ASSERTS && assert($k > 0);

				$ymids[$k] = $ymids[$k-1];

				break;

			    }

			while (list ($junk, $y) = each($matches)) {

			    if ($y > $this->seq[$k-1]) {

				USE_ASSERTS && 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;

			    }

			    else if (empty($this->in_seq[$y])) {

				$k = $this->_lcs_pos($y);

				USE_ASSERTS && assert($k > 0);

				$ymids[$k] = $ymids[$k-1];

			    }

			}

		    }

		}

		$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 _lcs_pos ($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;

		}

		USE_ASSERTS && assert($ypos != $this->seq[$end]);

		$this->in_seq[$this->seq[$end]] = false;

		$this->seq[$end] = $ypos;

		$this->in_seq[$ypos] = 1;

		return $end;

	    }

	    /* Find 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;

		    }

		}

	    }

	    /* Adjust 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 _shift_boundaries ($lines, &$changed, $other_changed) {

		$i = 0;

		$j = 0;

		USE_ASSERTS && assert('sizeof($lines) == sizeof($changed)');

		$len = sizeof($lines);

		$other_len = sizeof($other_changed);

		while (1) {

		    /*

		     * Scan forwards to find 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]) {

			USE_ASSERTS && 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--;

			    USE_ASSERTS && assert('$j > 0');

			    while ($other_changed[--$j])

				continue;

			    USE_ASSERTS && 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++;

			    USE_ASSERTS && 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;

			USE_ASSERTS && assert('$j > 0');

			while ($other_changed[--$j])

			    continue;

			USE_ASSERTS && assert('$j >= 0 && !$other_changed[$j]');

		    }

		}

	    }

	}

	/**

	 * Class representing a 'diff' between two sequences of strings.

	 */

	class Diff

	{

	    var $edits;

	    /**

	     * Constructor.

	     * Computes diff between sequences of strings.

	     *

	     * @param $from_lines array An array of strings.

	     *        (Typically these are lines from a file.)

	     * @param $to_lines array An array of strings.

	     */

	    function Diff($from_lines, $to_lines) {

		$eng = new _DiffEngine;

		$this->edits = $eng->diff($from_lines, $to_lines);

	    }

	}

	/**

	 * A class to format Diffs

	 *

	 * This class formats the diff in classic diff format.

	 * It is intended that this class be customized via inheritance,

	 * to obtain fancier outputs.

	 */

	class DiffFormatter

	{

	    /**

	     * Format a diff.

	     *

	     * @param $diff object A Diff object.

	     * @return string The formatted output.

	     */

	    function format($diff) {

		$xi = $yi = 1;

		$block = false;

		$context = array();

		$this->_start_diff();

		foreach ($diff->edits as $edit) {

		    if ($edit->type == 'copy') {

			if (is_array($block)) {

			    if (sizeof($edit->orig) <= 0) {

				$block[] = $edit;

			    }

			    else{

				$this->_block($x0, + $xi - $x0,

					      $y0, + $yi - $y0,

					      $block);

				$block = false;

			    }

			}

		    }

		    else {

			if (! is_array($block)) {

			    $x0 = $xi;

			    $y0 = $yi;

			    $block = array();

			}

			$block[] = $edit;

		    }

		    if ($edit->orig)

			$xi += sizeof($edit->orig);

		    if ($edit->final)

			$yi += sizeof($edit->final);

		}

		if (is_array($block))

		    $this->_block($x0, $xi - $x0,

				  $y0, $yi - $y0,

				  $block);

		return $this->_end_diff();

	    }

	    function _block($xbeg, $xlen, $ybeg, $ylen, &$edits) {

		$this->_start_block($this->_block_header($xbeg, $xlen, $ybeg, $ylen));

	    }

	    function _start_diff() {

		ob_start();

	    }

	    function _end_diff() {

		$val = ob_get_contents();

		ob_end_clean();

		return $val;

	    }

	    function _block_header($xbeg, $xlen, $ybeg, $ylen) {

		if ($xlen > 1)

		    $xbeg .= "," . ($xbeg + $xlen - 1);

		if ($ylen > 1)

		    $ybeg .= "," . ($ybeg + $ylen - 1);

		return $xbeg . ($xlen ? ($ylen ? 'c' : 'd') : 'a') . $ybeg;

	    }

	    function _start_block($header) {

		echo $header."\n";

	    }

	}

?>

</div>