alexrudd
pm me if you read this
Bandwidth Hog
Joined: 06 Oct 2004
Posts: 2335
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 Posted: 14 Apr 2006 12:16:12 pm Post subject: |
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Brazucs wrote: kermmartian wrote: Excellent question: there is a reason. I'm working on making the colorized syntax creatable by the SC2 bot, and there are several uses of bold, italics, and img tags that require BBCode, available in a quotebox but not a codebox. [post="75437"]<{POST_SNAPBACK}>[/post] Colorized syntax?! What a genius idea! [post="75515"]<{POST_SNAPBACK}>[/post] No offense, of course
Well, I know absolutely nothing about php, but here is how MediaWiki (what powers Wikipedia) does it:
[code]<?php
/**
* See diff.doc
* @package MediaWiki
* @subpackage DifferenceEngine
*/
/** */
require_once( 'Revision.php' );
define( 'MAX_DIFF_LINE', 10000 );
define( 'MAX_DIFF_XREF_LENGTH', 10000 );
/**
* @todo document
* @access public
* @package MediaWiki
* @subpackage DifferenceEngine
*/
class DifferenceEngine {
/**#@+
* @access private
*/
var $mOldid, $mNewid, $mTitle;
var $mOldtitle, $mNewtitle, $mPagetitle;
var $mOldtext, $mNewtext;
var $mOldPage, $mNewPage;
var $mRcidMarkPatrolled;
var $mOldRev, $mNewRev;
var $mRevisionsLoaded = false; // Have the revisions been loaded
var $mTextLoaded = 0; // How many text blobs have been loaded, 0, 1 or 2?
/**#@-*/
/**
* Constructor
* @param Title $titleObj Title object that the diff is associated with
* @param integer $old Old ID we want to show and diff with.
* @param string $new Either 'prev' or 'next'.
* @param integer $rcid ??? (default 0)
*/
function DifferenceEngine( $titleObj = null, $old = 0, $new = 0, $rcid = 0 ) {
$this->mTitle = $titleObj;
wfDebug("DifferenceEngine old '$old' new '$new' rcid '$rcid'\n");
if ( 'prev' === $new ) {
# Show diff between revision $old and the previous one.
# Get previous one from DB.
#
$this->mNewid = intval($old);
$this->mOldid = $this->mTitle->getPreviousRevisionID( $this->mNewid );
} elseif ( 'next' === $new ) {
# Show diff between revision $old and the previous one.
# Get previous one from DB.
#
$this->mOldid = intval($old);
$this->mNewid = $this->mTitle->getNextRevisionID( $this->mOldid );
if ( false === $this->mNewid ) {
# if no result, NewId points to the newest old revision. The only newer
# revision is cur, which is "0".
$this->mNewid = 0;
}
} else {
$this->mOldid = intval($old);
$this->mNewid = intval($new);
}
$this->mRcidMarkPatrolled = intval($rcid); # force it to be an integer
}
function showDiffPage() {
global $wgUser, $wgOut, $wgContLang, $wgUseExternalEditor, $wgUseRCPatrol;
$fname = 'DifferenceEngine::showDiffPage';
wfProfileIn( $fname );
# If external diffs are enabled both globally and for the user,
# we'll use the application/x-external-editor interface to call
# an external diff tool like kompare, kdiff3, etc.
if($wgUseExternalEditor && $wgUser->getOption('externaldiff')) {
global $wgInputEncoding,$wgServer,$wgScript,$wgLang;
$wgOut->disable();
header ( "Content-type: application/x-external-editor; charset=".$wgInputEncoding );
$url1=$this->mTitle->getFullURL("action=raw&oldid=".$this->mOldid);
$url2=$this->mTitle->getFullURL("action=raw&oldid=".$this->mNewid);
$special=$wgLang->getNsText(NS_SPECIAL);
$control=<<<CONTROL
[Process]
Type=Diff text
Engine=MediaWiki
Script={$wgServer}{$wgScript}
Special namespace={$special}
[File]
Extension=wiki
URL=$url1
[File 2]
Extension=wiki
URL=$url2
CONTROL;
echo($control);
return;
}
$t = $this->mTitle->getPrefixedText() . " (Diff: {$this->mOldid}, " .
"{$this->mNewid})";
$mtext = wfMsg( 'missingarticle', "<nowiki>$t</nowiki>" );
$wgOut->setArticleFlag( false );
if ( ! $this->loadRevisionData() ) {
$wgOut->setPagetitle( wfMsg( 'errorpagetitle' ) );
$wgOut->addWikitext( $mtext );
wfProfileOut( $fname );
return;
}
if ( $this->mNewRev->isCurrent() ) {
$wgOut->setArticleFlag( true );
}
# mOldid is false if the difference engine is called with a "vague" query for
# a diff between a version V and its previous version V' AND the version V
# is the first version of that article. In that case, V' does not exist.
if ( $this->mOldid === false ) {
$this->showFirstRevision();
wfProfileOut( $fname );
return;
}
$wgOut->suppressQuickbar();
$oldTitle = $this->mOldPage->getPrefixedText();
$newTitle = $this->mNewPage->getPrefixedText();
if( $oldTitle == $newTitle ) {
$wgOut->setPageTitle( $newTitle );
} else {
$wgOut->setPageTitle( $oldTitle . ', ' . $newTitle );
}
$wgOut->setSubtitle( wfMsg( 'difference' ) );
$wgOut->setRobotpolicy( 'noindex,follow' );
if ( !( $this->mOldPage->userCanRead() && $this->mNewPage->userCanRead() ) ) {
$wgOut->loginToUse();
$wgOut->output();
wfProfileOut( $fname );
exit;
}
$sk = $wgUser->getSkin();
$talk = $wgContLang->getNsText( NS_TALK );
$contribs = wfMsg( 'contribslink' );
if ( $this->mNewRev->isCurrent() && $wgUser->isAllowed('rollback') ) {
$username = $this->mNewRev->getUserText();
$rollback = ' <strong>[' . $sk->makeKnownLinkObj( $this->mTitle, wfMsg( 'rollbacklink' ),
'action=rollback&from=' . urlencode( $username ) .
'&token=' . urlencode( $wgUser->editToken( array( $this->mTitle->getPrefixedText(), $username ) ) ) ) .
']</strong>';
} else {
$rollback = '';
}
if( $wgUseRCPatrol && $this->mRcidMarkPatrolled != 0 && $wgUser->isAllowed( 'patrol' ) ) {
$patrol = ' [' . $sk->makeKnownLinkObj( $this->mTitle, wfMsg( 'markaspatrolleddiff' ), "action=markpatrolled&rcid={$this->mRcidMarkPatrolled}" ) . ']';
} else {
$patrol = '';
}
$prevlink = $sk->makeKnownLinkObj( $this->mTitle, wfMsgHtml( 'previousdiff' ),
'diff=prev&oldid='.$this->mOldid, '', '', 'id="differences-prevlink"' );
if ( $this->mNewRev->isCurrent() ) {
$nextlink = '';
} else {
$nextlink = $sk->makeKnownLinkObj( $this->mTitle, wfMsgHtml( 'nextdiff' ),
'diff=next&oldid='.$this->mNewid, '', '', 'id="differences-nextlink"' );
}
$oldHeader = "<strong>{$this->mOldtitle}</strong><br />" .
$sk->revUserTools( $this->mOldRev ) . "<br />" .
$sk->revComment( $this->mOldRev ) . "<br />" .
$prevlink;
$newHeader = "<strong>{$this->mNewtitle}</strong><br />" .
$sk->revUserTools( $this->mNewRev ) . " $rollback<br />" .
$sk->revComment( $this->mNewRev ) . "<br />" .
$nextlink . $patrol;
$this->showDiff( $oldHeader, $newHeader );
$wgOut->addHTML( "<hr /><h2>{$this->mPagetitle}</h2>\n" );
if( !$this->mNewRev->isCurrent() ) {
$oldEditSectionSetting = $wgOut->mParserOptions->setEditSection( false );
}
$this->loadNewText();
if( is_object( $this->mNewRev ) ) {
$wgOut->setRevisionId( $this->mNewRev->getId() );
}
$wgOut->addSecondaryWikiText( $this->mNewtext );
if( !$this->mNewRev->isCurrent() ) {
$wgOut->mParserOptions->setEditSection( $oldEditSectionSetting );
}
wfProfileOut( $fname );
}
/**
* Show the first revision of an article. Uses normal diff headers in
* contrast to normal "old revision" display style.
*/
function showFirstRevision() {
global $wgOut, $wgUser;
$fname = 'DifferenceEngine::showFirstRevision';
wfProfileIn( $fname );
# Get article text from the DB
#
if ( ! $this->loadNewText() ) {
$t = $this->mTitle->getPrefixedText() . " (Diff: {$this->mOldid}, " .
"{$this->mNewid})";
$mtext = wfMsg( 'missingarticle', "<nowiki>$t</nowiki>" );
$wgOut->setPagetitle( wfMsg( 'errorpagetitle' ) );
$wgOut->addWikitext( $mtext );
wfProfileOut( $fname );
return;
}
if ( $this->mNewRev->isCurrent() ) {
$wgOut->setArticleFlag( true );
}
# Check if user is allowed to look at this page. If not, bail out.
#
if ( !( $this->mTitle->userCanRead() ) ) {
$wgOut->loginToUse();
$wgOut->output();
wfProfileOut( $fname );
exit;
}
# Prepare the header box
#
$sk = $wgUser->getSkin();
$nextlink = $sk->makeKnownLinkObj( $this->mTitle, wfMsgHtml( 'nextdiff' ), 'diff=next&oldid='.$this->mNewid, '', '', 'id="differences-nextlink"' );
$header = "<div class=\"firstrevisionheader\" style=\"text-align: center\"><strong>{$this->mOldtitle}</strong><br />" .
$sk->revUserTools( $this->mNewRev ) . "<br />" .
$sk->revComment( $this->mNewRev ) . "<br />" .
$nextlink . "</div>\n";
$wgOut->addHTML( $header );
$wgOut->setSubtitle( wfMsg( 'difference' ) );
$wgOut->setRobotpolicy( 'noindex,nofollow' );
# Show current revision
#
$wgOut->addHTML( "<hr /><h2>{$this->mPagetitle}</h2>\n" );
if( is_object( $this->mNewRev ) ) {
$wgOut->setRevisionId( $this->mNewRev->getId() );
}
$wgOut->addSecondaryWikiText( $this->mNewtext );
wfProfileOut( $fname );
}
/**
* Get the diff text, send it to $wgOut
* Returns false if the diff could not be generated, otherwise returns true
*/
function showDiff( $otitle, $ntitle ) {
global $wgOut;
$diff = $this->getDiff( $otitle, $ntitle );
if ( $diff === false ) {
$wgOut->addWikitext( wfMsg( 'missingarticle', "<nowiki>(fixme, bug)</nowiki>" ) );
return false;
} else {
$wgOut->addHTML( $diff );
return true;
}
}
/**
* Get diff table, including header
* Note that the interface has changed, it's no longer static.
* Returns false on error
*/
function getDiff( $otitle, $ntitle ) {
$body = $this->getDiffBody();
if ( $body === false ) {
return false;
} else {
return $this->addHeader( $body, $otitle, $ntitle );
}
}
/**
* Get the diff table body, without header
* Results are cached
* Returns false on error
*/
function getDiffBody() {
global $wgMemc, $wgDBname;
$fname = 'DifferenceEngine::getDiffBody';
wfProfileIn( $fname );
// Cacheable?
$key = false;
if ( $this->mOldid && $this->mNewid ) {
// Try cache
$key = "$wgDBname:diff:oldid:{$this->mOldid}:newid:{$this->mNewid}";
$difftext = $wgMemc->get( $key );
if ( $difftext ) {
wfIncrStats( 'diff_cache_hit' );
$difftext = $this->localiseLineNumbers( $difftext );
$difftext .= "\n<!-- diff cache key $key -->\n";
wfProfileOut( $fname );
return $difftext;
}
}
if ( !$this->loadText() ) {
wfProfileOut( $fname );
return false;
}
$difftext = $this->generateDiffBody( $this->mOldtext, $this->mNewtext );
// Save to cache for 7 days
if ( $key !== false && $difftext !== false ) {
wfIncrStats( 'diff_cache_miss' );
$wgMemc->set( $key, $difftext, 7*86400 );
} else {
wfIncrStats( 'diff_uncacheable' );
}
// Replace line numbers with the text in the user's language
if ( $difftext !== false ) {
$difftext = $this->localiseLineNumbers( $difftext );
}
wfProfileOut( $fname );
return $difftext;
}
/**
* Generate a diff, no caching
* $otext and $ntext must be already segmented
*/
function generateDiffBody( $otext, $ntext ) {
global $wgExternalDiffEngine, $wgContLang;
$fname = 'DifferenceEngine::generateDiffBody';
$otext = str_replace( "\r\n", "\n", $otext );
$ntext = str_replace( "\r\n", "\n", $ntext );
if ( $wgExternalDiffEngine == 'wikidiff' ) {
# For historical reasons, external diff engine expects
# input text to be HTML-escaped already
$otext = htmlspecialchars ( $wgContLang->segmentForDiff( $otext ) );
$ntext = htmlspecialchars ( $wgContLang->segmentForDiff( $ntext ) );
if( !function_exists( 'wikidiff_do_diff' ) ) {
dl('php_wikidiff.so');
}
return $wgContLang->unsegementForDiff( wikidiff_do_diff( $otext, $ntext, 2 ) );
}
if ( $wgExternalDiffEngine == 'wikidiff2' ) {
# Better external diff engine, the 2 may some day be dropped
# This one does the escaping and segmenting itself
if ( !function_exists( 'wikidiff2_do_diff' ) ) {
wfProfileIn( "$fname-dl" );
@dl('php_wikidiff2.so');
wfProfileOut( "$fname-dl" );
}
if ( function_exists( 'wikidiff2_do_diff' ) ) {
wfProfileIn( 'wikidiff2_do_diff' );
$text = wikidiff2_do_diff( $otext, $ntext, 2 );
wfProfileOut( 'wikidiff2_do_diff' );
return $text;
}
}
if ( $wgExternalDiffEngine !== false ) {
# Diff via the shell
global $wgTmpDirectory;
$tempName1 = tempnam( $wgTmpDirectory, 'diff_' );
$tempName2 = tempnam( $wgTmpDirectory, 'diff_' );
$tempFile1 = fopen( $tempName1, "w" );
if ( !$tempFile1 ) {
wfProfileOut( $fname );
return false;
}
$tempFile2 = fopen( $tempName2, "w" );
if ( !$tempFile2 ) {
wfProfileOut( $fname );
return false;
}
fwrite( $tempFile1, $otext );
fwrite( $tempFile2, $ntext );
fclose( $tempFile1 );
fclose( $tempFile2 );
$cmd = wfEscapeShellArg( $wgExternalDiffEngine, $tempName1, $tempName2 );
wfProfileIn( "$fname-shellexec" );
$difftext = wfShellExec( $cmd );
wfProfileOut( "$fname-shellexec" );
unlink( $tempName1 );
unlink( $tempName2 );
return $difftext;
}
# Native PHP diff
$ota = explode( "\n", $wgContLang->segmentForDiff( $otext ) );
$nta = explode( "\n", $wgContLang->segmentForDiff( $ntext ) );
$diffs =& new Diff( $ota, $nta );
$formatter =& new TableDiffFormatter();
return $wgContLang->unsegmentForDiff( $formatter->format( $diffs ) );
}
/**
* Replace line numbers with the text in the user's language
*/
function localiseLineNumbers( $text ) {
return preg_replace_callback( '/<!--LINE (\d+)-->/',
array( &$this, 'localiseLineNumbersCb' ), $text );
}
function localiseLineNumbersCb( $matches ) {
global $wgLang;
return wfMsg( 'lineno', $wgLang->formatNum( $matches[1] ) );
}
/**
* Add the header to a diff body
*/
function addHeader( $diff, $otitle, $ntitle ) {
$out = "
<table border='0' width='98%' cellpadding='0' cellspacing='4' class='diff'>
<tr>
<td colspan='2' width='50%' align='center' class='diff-otitle'>{$otitle}</td>
<td colspan='2' width='50%' align='center' class='diff-ntitle'>{$ntitle}</td>
</tr>
$diff
</table>
";
return $out;
}
/**
* Use specified text instead of loading from the database
*/
function setText( $oldText, $newText ) {
$this->mOldtext = $oldText;
$this->mNewtext = $newText;
$this->mTextLoaded = 2;
}
/**
* Load revision metadata for the specified articles. If newid is 0, then compare
* the old article in oldid to the current article; if oldid is 0, then
* compare the current article to the immediately previous one (ignoring the
* value of newid).
*
* If oldid is false, leave the corresponding revision object set
* to false. This is impossible via ordinary user input, and is provided for
* API convenience.
*/
function loadRevisionData() {
global $wgLang;
if ( $this->mRevisionsLoaded ) {
return true;
} else {
// Whether it succeeds or fails, we don't want to try again
$this->mRevisionsLoaded = true;
}
// Load the new revision object
if( $this->mNewid ) {
$this->mNewRev = Revision::newFromId( $this->mNewid );
} else {
$this->mNewRev = Revision::newFromTitle( $this->mTitle );
}
if( is_null( $this->mNewRev ) ) {
return false;
}
// Set assorted variables
if( $this->mNewRev->isCurrent() ) {
$this->mPagetitle = htmlspecialchars( wfMsg( 'currentrev' ) );
$this->mNewPage = $this->mTitle;
$newLink = $this->mNewPage->escapeLocalUrl();
$this->mNewtitle = "<a href='$newLink'>{$this->mPagetitle}</a>";
} else {
$this->mNewPage = $this->mNewRev->getTitle();
$newLink = $this->mNewPage->escapeLocalUrl ('oldid=' . $this->mNewid );
$t = $wgLang->timeanddate( $this->mNewRev->getTimestamp(), true );
$this->mPagetitle = htmlspecialchars( wfMsg( 'revisionasof', $t ) );
$this->mNewtitle = "<a href='$newLink'>{$this->mPagetitle}</a>";
}
// Load the old revision object
$this->mOldRev = false;
if( $this->mOldid ) {
$this->mOldRev = Revision::newFromId( $this->mOldid );
} elseif ( $this->mOldid === 0 ) {
$rev = $this->mNewRev->getPrevious();
if( $rev ) {
$this->mOldid = $rev->getId();
$this->mOldRev = $rev;
} else {
// No previous revision; mark to show as first-version only.
$this->mOldid = false;
$this->mOldRev = false;
}
}/* elseif ( $this->mOldid === false ) leave mOldRev false; */
if( is_null( $this->mOldRev ) ) {
return false;
}
if ( $this->mOldRev ) {
$this->mOldPage = $this->mOldRev->getTitle();
$t = $wgLang->timeanddate( $this->mOldRev->getTimestamp(), true );
$oldLink = $this->mOldPage->escapeLocalUrl( 'oldid=' . $this->mOldid );
$this->mOldtitle = "<a href='$oldLink'>" . htmlspecialchars( wfMsg( 'revisionasof', $t ) ) . '</a>';
}
return true;
}
/**
* Load the text of the revisions, as well as revision data.
*/
function loadText() {
if ( $this->mTextLoaded == 2 ) {
return true;
} else {
// Whether it succeeds or fails, we don't want to try again
$this->mTextLoaded = 2;
}
if ( !$this->loadRevisionData() ) {
return false;
}
if ( $this->mOldRev ) {
// FIXME: permission tests
$this->mOldtext = $this->mOldRev->getText();
if ( $this->mOldtext === false ) {
return false;
}
}
if ( $this->mNewRev ) {
$this->mNewtext = $this->mNewRev->getText();
if ( $this->mNewtext === false ) {
return false;
}
}
return true;
}
/**
* Load the text of the new revision, not the old one
*/
function loadNewText() {
if ( $this->mTextLoaded >= 1 ) {
return true;
} else {
$this->mTextLoaded = 1;
}
if ( !$this->loadRevisionData() ) {
return false;
}
$this->mNewtext = $this->mNewRev->getText();
return true;
}
}
// A PHP diff engine for phpwiki. (Taken from phpwiki-1.3.3)
//
// Copyright © 2000, 2001 Geoffrey T. Dairiki <dairiki@dairiki.org>
// You may copy this code freely under the conditions of the GPL.
//
define('USE_ASSERTS', function_exists('assert'));
/**
* @todo document
* @access private
* @package MediaWiki
* @subpackage DifferenceEngine
*/
class _DiffOp {
var $type;
var $orig;
var $closing;
function reverse() {
trigger_error('pure virtual', E_USER_ERROR);
}
function norig() {
return $this->orig ? sizeof($this->orig) : 0;
}
function nclosing() {
return $this->closing ? sizeof($this->closing) : 0;
}
}
/**
* @todo document
* @access private
* @package MediaWiki
* @subpackage DifferenceEngine
*/
class _DiffOp_Copy extends _DiffOp {
var $type = 'copy';
function _DiffOp_Copy ($orig, $closing = false) {
if (!is_array($closing))
$closing = $orig;
$this->orig = $orig;
$this->closing = $closing;
}
function reverse() {
return new _DiffOp_Copy($this->closing, $this->orig);
}
}
/**
* @todo document
* @access private
* @package MediaWiki
* @subpackage DifferenceEngine
*/
class _DiffOp_Delete extends _DiffOp {
var $type = 'delete';
function _DiffOp_Delete ($lines) {
$this->orig = $lines;
$this->closing = false;
}
function reverse() {
return new _DiffOp_Add($this->orig);
}
}
/**
* @todo document
* @access private
* @package MediaWiki
* @subpackage DifferenceEngine
*/
class _DiffOp_Add extends _DiffOp {
var $type = 'add';
function _DiffOp_Add ($lines) {
$this->closing = $lines;
$this->orig = false;
}
function reverse() {
return new _DiffOp_Delete($this->closing);
}
}
/**
* @todo document
* @access private
* @package MediaWiki
* @subpackage DifferenceEngine
*/
class _DiffOp_Change extends _DiffOp {
var $type = 'change';
function _DiffOp_Change ($orig, $closing) {
$this->orig = $orig;
$this->closing = $closing;
}
function reverse() {
return new _DiffOp_Change($this->closing, $this->orig);
}
}
/**
* Class used internally by Diff to actually compute the diffs.
*
* The algorithm used here is mostly lifted from the perl module
* Algorithm::Diff (version 1.06) by Ned Konz, which is available at:
* http://www.perl.com/CPAN/authors/id/N/NE/N...m-Diff-1.06.zip
*
* More ideas are taken from:
* http://www.ics.uci.edu/~eppstein/161/960229.html
*
* Some ideas are (and a bit of code) are from from analyze.c, from GNU
* diffutils-2.7, which can be found at:
* ftp://gnudist.gnu.org/pub/gnu/diffutils/diffutils-2.7.tar.gz
*
* closingly, some ideas (subdivision by NCHUNKS > 2, and some optimizations)
* are my own.
*
* Line length limits for robustness added by Tim Starling, 2005-08-31
*
* @author Geoffrey T. Dairiki, Tim Starling
* @access private
* @package MediaWiki
* @subpackage DifferenceEngine
*/
class _DiffEngine
{
function diff ($from_lines, $to_lines) {
$fname = '_DiffEngine::diff';
wfProfileIn( $fname );
$n_from = sizeof($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++) {
$xhash[$this->_line_hash($from_lines[$xi])] = 1;
}
for ($yi = $skip; $yi < $n_to - $endskip; $yi++) {
$line = $to_lines[$yi];
if ( ($this->ychanged[$yi] = empty($xhash[$this->_line_hash($line)])) )
continue;
$yhash[$this->_line_hash($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($yhash[$this->_line_hash($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);
}
wfProfileOut( $fname );
return $edits;
}
/**
* Returns the whole line if it's small enough, or the MD5 hash otherwise
*/
function _line_hash( $line ) {
if ( strlen( $line ) > MAX_DIFF_XREF_LENGTH ) {
return md5( $line );
} else {
return $line;
}
}
/* Divide the Largest Common Subsequence (LCS) of the sequences
* [XOFF, XLIM) and [YOFF, YLIM) into NCHUNKS approximately equally
* sized segments.
*
* Returns (LCS, PTS). LCS is the length of the LCS. PTS is an
* array of NCHUNKS+1 (X, Y) indexes giving the diving points between
* sub sequences. The first sub-sequence is contained in [X0, X1),
* [Y0, Y1), the second in [X1, X2), [Y1, Y2) and so on. Note
* that (X0, Y0) == (XOFF, YOFF) and
* (X[NCHUNKS], Y[NCHUNKS]) == (XLIM, YLIM).
*
* This function assumes that the first lines of the specified portions
* of the two files do not match, and likewise that the last lines do not
* match. The caller must trim matching lines from the beginning and end
* of the portions it is going to specify.
*/
function _diag ($xoff, $xlim, $yoff, $ylim, $nchunks) {
$fname = '_DiffEngine::_diag';
wfProfileIn( $fname );
$flip = false;
if ($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; $chunk++) {
wfProfileIn( "$fname-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];
}
}
}
wfProfileOut( "$fname-chunk" );
}
$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);
wfProfileOut( $fname );
return array($this->lcs, $seps);
}
function _lcs_pos ($ypos) {
$fname = '_DiffEngine::_lcs_pos';
wfProfileIn( $fname );
$end = $this->lcs;
if ($end == 0 || $ypos > $this->seq[$end]) {
$this->seq[++$this->lcs] = $ypos;
$this->in_seq[$ypos] = 1;
wfProfileOut( $fname );
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;
wfProfileOut( $fname );
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) {
$fname = '_DiffEngine::_compareseq';
wfProfileIn( $fname );
// Slide down the bottom initial diagonal.
while ($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;
}
}
wfProfileOut( $fname );
}
/* Adjust inserts/deletes of identical lines to join changes
* as much as possible.
*
* We do something when a run of changed lines include a
* line at one end and has an excluded, identical line at the other.
* We are free to choose which identical line is included.
* `compareseq' usually chooses the one at the beginning,
* but usually it is cleaner to consider the following identical line
* to be the "change".
*
* This is extracted verbatim from analyze.c (GNU diffutils-2.7).
*/
function _shift_boundaries ($lines, &$changed, $other_changed) {
$fname = '_DiffEngine::_shift_boundaries';
wfProfileIn( $fname );
$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]');
}
}
wfProfileOut( $fname );
}
}
/**
* Class representing a 'diff' between two sequences of strings.
* @todo document
* @access private
* @package MediaWiki
* @subpackage DifferenceEngine
*/
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, $to_lines);
//$this->_check($from_lines, $to_lines);
}
/**
* Compute reversed Diff.
*
* SYNOPSIS:
*
* $diff = new Diff($lines1, $lines2);
* $rev = $diff->reverse();
* @return object A Diff object representing the inverse of the
* original diff.
*/
function reverse () {
$rev = $this;
$rev->edits = array();
foreach ($this->edits as $edit) {
$rev->edits[] = $edit->reverse();
}
return $rev;
}
/**
* Check for empty diff.
*
* @return bool True iff two sequences were identical.
*/
function isEmpty () {
foreach ($this->edits as $edit) {
if ($edit->type != 'copy')
return false;
}
return true;
}
/**
* Compute the length of the Longest Common Subsequence (LCS).
*
* This is mostly for diagnostic purposed.
*
* @return int The length of the LCS.
*/
function lcs () {
$lcs = 0;
foreach ($this->edits as $edit) {
if ($edit->type == 'copy')
$lcs += sizeof($edit->orig);
}
return $lcs;
}
/**
* Get the original set of lines.
*
* This reconstructs the $from_lines parameter passed to the
* constructor.
*
* @return array The original sequence of strings.
*/
function orig() {
$lines = array();
foreach ($this->edits as $edit) {
if ($edit->orig)
array_splice($lines, sizeof($lines), 0, $edit->orig);
}
return $lines;
}
/**
* Get the closing set of lines.
*
* This reconstructs the $to_lines parameter passed to the
* constructor.
*
* @return array The sequence of strings.
*/
function closing() {
$lines = array();
foreach ($this->edits as $edit) {
if ($edit->closing)
array_splice($lines, sizeof($lines), 0, $edit->closing);
}
return $lines;
}
/**
* Check a Diff for validity.
*
* This is here only for debugging purposes.
*/
function _check ($from_lines, $to_lines) {
$fname = 'Diff::_check';
wfProfileIn( $fname );
if (serialize($from_lines) != serialize($this->orig()))
trigger_error("Reconstructed original doesn't match", E_USER_ERROR);
if (serialize($to_lines) != serialize($this->closing()))
trigger_error("Reconstructed closing doesn't match", E_USER_ERROR);
$rev = $this->reverse();
if (serialize($to_lines) != serialize($rev->orig()))
trigger_error("Reversed original doesn't match", E_USER_ERROR);
if (serialize($from_lines) != serialize($rev->closing()))
trigger_error("Reversed closing doesn't match", E_USER_ERROR);
$prevtype = 'none';
foreach ($this->edits as $edit) {
if ( $prevtype == $edit->type )
trigger_error("Edit sequence is non-optimal", E_USER_ERROR);
$prevtype = $edit->type;
}
$lcs = $this->lcs();
trigger_error('Diff okay: LCS = '.$lcs, E_USER_NOTICE);
wfProfileOut( $fname );
}
}
/**
* FIXME: bad name.
* @todo document
* @access private
* @package MediaWiki
* @subpackage DifferenceEngine
*/
class MappedDiff extends Diff
{
/**
* Constructor.
*
* Computes diff between sequences of strings.
*
* This can be used to compute things like
* case-insensitve diffs, or diffs which ignore
* changes in white-space.
*
* @param $from_lines array An array of strings.
* (Typically these are lines from a file.)
*
* @param $to_lines array An array of strings.
*
* @param $mapped_from_lines array This array should
* have the same size number of elements as $from_lines.
* The elements in $mapped_from_lines and
* $mapped_to_lines are what is actually compared
* when computing the diff.
*
* @param $mapped_to_lines array This array should
* have the same number of elements as $to_lines.
*/
function MappedDiff($from_lines, $to_lines,
$mapped_from_lines, $mapped_to_lines) {
$fname = 'MappedDiff::MappedDiff';
wfProfileIn( $fname );
assert(sizeof($from_lines) == sizeof($mapped_from_lines));
assert(sizeof($to_lines) == sizeof($mapped_to_lines));
$this->Diff($mapped_from_lines, $mapped_to_lines);
$xi = $yi = 0;
for ($i = 0; $i < sizeof($this->edits); $i++) {
$orig = &$this->edits[$i]->orig;
if (is_array($orig)) {
$orig = array_slice($from_lines, $xi, sizeof($orig));
$xi += sizeof($orig);
}
$closing = &$this->edits[$i]->closing;
if (is_array($closing)) {
$closing = array_slice($to_lines, $yi, sizeof($closing));
$yi += sizeof($closing);
}
}
wfProfileOut( $fname );
}
}
/**
* 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.
* @todo document
* @access private
* @package MediaWiki
* @subpackage DifferenceEngine
*/
class DiffFormatter
{
/**
* Number of leading context "lines" to preserve.
*
* This should be left at zero for this class, but subclasses
* may want to set this to other values.
*/
var $leading_context_lines = 0;
/**
* Number of trailing context "lines" to preserve.
*
* This should be left at zero for this class, but subclasses
* may want to set this to other values.
*/
var $trailing_context_lines = 0;
/**
* Format a diff.
*
* @param $diff object A Diff object.
* @return string The formatted output.
*/
function format($diff) {
$fname = 'DiffFormatter::format';
wfProfileIn( $fname );
$xi = $yi = 1;
$block = false;
$context = array();
$nlead = $this->leading_context_lines;
$ntrail = $this->trailing_context_lines;
$this->_start_diff();
foreach ($diff->edits as $edit) {
if ($edit->type == 'copy') {
if (is_array($block)) {
if (sizeof($edit->orig) <= $nlead + $ntrail) {
$block[] = $edit;
}
else{
if ($ntrail) {
$context = array_slice($edit->orig, 0, $ntrail);
$block[] = new _DiffOp_Copy($context);
}
$this->_block($x0, $ntrail + $xi - $x0,
$y0, $ntrail + $yi - $y0,
$block);
$block = false;
}
}
$context = $edit->orig;
}
else {
if (! is_array($block)) {
$context = array_slice($context, sizeof($context) - $nlead);
$x0 = $xi - sizeof($context);
$y0 = $yi - sizeof($context);
$block = array();
if ($context)
$block[] = new _DiffOp_Copy($context);
}
$block[] = $edit;
}
if ($edit->orig)
$xi += sizeof($edit->orig);
if ($edit->closing)
$yi += sizeof($edit->closing);
}
if (is_array($block))
$this->_block($x0, $xi - $x0,
$y0, $yi - $y0,
$block);
$end = $this->_end_diff();
wfProfileOut( $fname );
return $end;
}
function _block($xbeg, $xlen, $ybeg, $ylen, &$edits) {
$fname = 'DiffFormatter::_block';
wfProfileIn( $fname );
$this->_start_block($this->_block_header($xbeg, $xlen, $ybeg, $ylen));
foreach ($edits as $edit) {
if ($edit->type == 'copy')
$this->_context($edit->orig);
elseif ($edit->type == 'add')
$this->_added($edit->closing);
elseif ($edit->type == 'delete')
$this->_deleted($edit->orig);
elseif ($edit->type == 'change')
$this->_changed($edit->orig, $edit->closing);
else
trigger_error('Unknown edit type', E_USER_ERROR);
}
$this->_end_block();
wfProfileOut( $fname );
}
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 $header;
}
function _end_block() {
}
function _lines($lines, $prefix = ' ') {
foreach ($lines as $line)
echo "$prefix $line\n";
}
function _context($lines) {
$this->_lines($lines);
}
function _added($lines) {
$this->_lines($lines, '>');
}
function _deleted($lines) {
$this->_lines($lines, '<');
}
function _changed($orig, $closing) {
$this->_deleted($orig);
echo "---\n";
$this->_added($closing);
}
}
/**
* Additions by Axel Boldt follow, partly taken from diff.php, phpwiki-1.3.3
*
*/
define('NBSP', ' '); // iso-8859-x non-breaking space.
/**
* @todo document
* @access private
* @package MediaWiki
* @subpackage DifferenceEngine
*/
class _HWLDF_WordAccumulator {
function _HWLDF_WordAccumulator () {
$this->_lines = array();
$this->_line = '';
$this->_group = '';
$this->_tag = '';
}
function _flushGroup ($new_tag) {
if ($this->_group !== '') {
if ($this->_tag == 'mark')
$this->_line .= '<span class="diffchange">' .
htmlspecialchars ( $this->_group ) . '</span>';
else
$this->_line .= htmlspecialchars ( $this->_group );
}
$this->_group = '';
$this->_tag = $new_tag;
}
function _flushLine ($new_tag) {
$this->_flushGroup($new_tag);
if ($this->_line != '')
array_push ( $this->_lines, $this->_line );
else
# make empty lines visible by inserting an NBSP
array_push ( $this->_lines, NBSP );
$this->_line = '';
}
function addWords ($words, $tag = '') {
if ($tag != $this->_tag)
$this->_flushGroup($tag);
foreach ($words as $word) {
// new-line should only come as first char of word.
if ($word == '')
continue;
if ($word[0] == "\n") {
$this->_flushLine($tag);
$word = substr($word, 1);
}
assert(!strstr($word, "\n"));
$this->_group .= $word;
}
}
function getLines() {
$this->_flushLine('~done');
return $this->_lines;
}
}
/**
* @todo document
* @access private
* @package MediaWiki
* @subpackage DifferenceEngine
*/
class WordLevelDiff extends MappedDiff
{
function WordLevelDiff ($orig_lines, $closing_lines) {
$fname = 'WordLevelDiff::WordLevelDiff';
wfProfileIn( $fname );
list ($orig_words, $orig_stripped) = $this->_split($orig_lines);
list ($closing_words, $closing_stripped) = $this->_split($closing_lines);
$this->MappedDiff($orig_words, $closing_words,
$orig_stripped, $closing_stripped);
wfProfileOut( $fname );
}
function _split($lines) {
$fname = 'WordLevelDiff::_split';
wfProfileIn( $fname );
$words = array();
$stripped = array();
$first = true;
foreach ( $lines as $line ) {
# If the line is too long, just pretend the entire line is one big word
# This prevents resource exhaustion problems
if ( $first ) {
$first = false;
} else {
$words[] = "\n";
$stripped[] = "\n";
}
if ( strlen( $line ) > MAX_DIFF_LINE ) {
$words[] = $line;
$stripped[] = $line;
} else {
if (preg_match_all('/ ( [^\S\n]+ | [0-9_A-Za-z\x80-\xff]+ | . ) (?: (?!< \n) [^\S\n])? /xs',
$line, $m))
{
$words = array_merge( $words, $m[0] );
$stripped = array_merge( $stripped, $m[1] );
}
}
}
wfProfileOut( $fname );
return array($words, $stripped);
}
function orig () {
$fname = 'WordLevelDiff::orig';
wfProfileIn( $fname );
$orig = new _HWLDF_WordAccumulator;
foreach ($this->edits as $edit) {
if ($edit->type == 'copy')
$orig->addWords($edit->orig);
elseif ($edit->orig)
$orig->addWords($edit->orig, 'mark');
}
$lines = $orig->getLines();
wfProfileOut( $fname );
return $lines;
}
function closing () {
$fname = 'WordLevelDiff::closing';
wfProfileIn( $fname );
$closing = new _HWLDF_WordAccumulator;
foreach ($this->edits as $edit) {
if ($edit->type == 'copy')
$closing->addWords($edit->closing);
elseif ($edit->closing)
$cl |
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Community News & Discuss Nspire => Technology & Calculator Open Topic
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