2a03980093
mt_rand() function has a maximum value of 2^31-1, which is small enough that duplicate values can occur due to the Birthday paradox, e.g. on the English Wikipedia. To fix this, add a wfRandom() function that calls mt_rand() twice to get the desired amount of randomness.
56 lines
1.5 KiB
PHP
56 lines
1.5 KiB
PHP
<?php
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/**
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* @version # $Id$
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* @package MediaWiki
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* @subpackage SpecialPage
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*/
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/**
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* Constructor
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*/
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function wfSpecialRandompage() {
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global $wgOut, $wgTitle, $wgArticle, $wgExtraRandompageSQL;
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$fname = 'wfSpecialRandompage';
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# NOTE! We use a literal constant in the SQL instead of the RAND()
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# function because RAND() will return a different value for every row
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# in the table. That's both very slow and returns results heavily
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# biased towards low values, as rows later in the table will likely
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# never be reached for comparison.
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#
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# Using a literal constant means the whole thing gets optimized on
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# the index, and the comparison is both fast and fair.
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# interpolation and sprintf() can muck up with locale-specific decimal separator
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$randstr = wfRandom();
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$db =& wfGetDB( DB_SLAVE );
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$use_index = $db->useIndexClause( 'cur_random' );
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$cur = $db->tableName( 'cur' );
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if ( $wgExtraRandompageSQL ) {
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$extra = "AND ($wgExtraRandompageSQL)";
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} else {
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$extra = '';
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}
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$sqlget = "SELECT cur_id,cur_title
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FROM $cur $use_index
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WHERE cur_namespace=0 AND cur_is_redirect=0 $extra
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AND cur_random>$randstr
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ORDER BY cur_random
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LIMIT 1";
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$res = $db->query( $sqlget, $fname );
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$title = null;
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if( $s = $db->fetchObject( $res ) ) {
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$title =& Title::makeTitle( NS_MAIN, $s->cur_title );
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}
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if( is_null( $title ) ) {
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# That's not supposed to happen :)
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$title =& Title::newFromText( wfMsg( 'mainpage' ) );
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}
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$wgOut->reportTime(); # for logfile
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$wgOut->redirect( $title->getFullUrl() );
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}
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?>
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