<?php
# Global functions used everywhere

$wgNumberOfArticles = -1; # Unset
$wgTotalViews = -1;
$wgTotalEdits = -1;

require_once( 'DatabaseFunctions.php' );
require_once( 'UpdateClasses.php' );
require_once( 'LogPage.php' );

/*
 * Compatibility functions
 */

# PHP <4.3.x is not actively supported; 4.1.x and 4.2.x might or might not work.
# <4.1.x will not work, as we use a number of features introduced in 4.1.0
# such as the new autoglobals.

if( !function_exists('iconv') ) {
	# iconv support is not in the default configuration and so may not be present.
	# Assume will only ever use utf-8 and iso-8859-1.
	# This will *not* work in all circumstances.
	function iconv( $from, $to, $string ) {
		if(strcasecmp( $from, $to ) == 0) return $string;
		if(strcasecmp( $from, 'utf-8' ) == 0) return utf8_decode( $string );
		if(strcasecmp( $to, 'utf-8' ) == 0) return utf8_encode( $string );
		return $string;
	}
}

if( !function_exists('file_get_contents') ) {
	# Exists in PHP 4.3.0+
	function file_get_contents( $filename ) {
		return implode( '', file( $filename ) );
	}
}

if( !function_exists('is_a') ) {
	# Exists in PHP 4.2.0+
	function is_a( $object, $class_name ) {
		return
			(strcasecmp( get_class( $object, $class_name ) == 0) ||
			 is_subclass_of( $object, $class_name ) );
	}
}

# html_entity_decode exists in PHP 4.3.0+ but is FATALLY BROKEN even then,
# with no UTF-8 support.
function do_html_entity_decode( $string, $quote_style=ENT_COMPAT, $charset='ISO-8859-1' ) {
	static $trans;
	if( !isset( $trans ) ) {
		$trans = array_flip( get_html_translation_table( HTML_ENTITIES, $quote_style ) );
		# Assumes $charset will always be the same through a run, and only understands
		# utf-8 or default. Note - mixing latin1 named entities and unicode numbered
		# ones will result in a bad link.
		if( strcasecmp( 'utf-8', $charset ) == 0 ) {
			$trans = array_map( 'utf8_encode', $trans );
		}
	}
	return strtr( $string, $trans );
}

$wgRandomSeeded = false;

function wfSeedRandom()
{
	global $wgRandomSeeded;

	if ( ! $wgRandomSeeded ) {
		$seed = hexdec(substr(md5(microtime()),-8)) & 0x7fffffff;
		mt_srand( $seed );
		$wgRandomSeeded = true;
	}
}

# Generates a URL from a URL-encoded title and a query string
# Title::getLocalURL() is preferred in most cases
#
function wfLocalUrl( $a, $q = '' )
{
	global $wgServer, $wgScript, $wgArticlePath;

	$a = str_replace( ' ', '_', $a );

	if ( '' == $a ) {
		if( '' == $q ) {
			$a = $wgScript;
		} else {
			$a = "{$wgScript}?{$q}";
		}	
	} else if ( '' == $q ) {
		$a = str_replace( "$1", $a, $wgArticlePath );
	} else if ($wgScript != '' ) {
		$a = "{$wgScript}?title={$a}&{$q}";	
	} else { //XXX hackish solution for toplevel wikis
		$a = "/{$a}?{$q}";	
	}
	return $a;
}

function wfLocalUrlE( $a, $q = '' )
{
	return wfEscapeHTML( wfLocalUrl( $a, $q ) );
	# die( "Call to obsolete function wfLocalUrlE()" );
}

function wfFullUrl( $a, $q = '' ) {
	wfDebugDieBacktrace( 'Call to obsolete function wfFullUrl(); use Title::getFullURL' );
}

function wfFullUrlE( $a, $q = '' ) {
	wfDebugDieBacktrace( 'Call to obsolete function wfFullUrlE(); use Title::getFullUrlE' );

}

// orphan function wfThumbUrl( $img )
//{
//	global $wgUploadPath;
//
//	$nt = Title::newFromText( $img );
//	if( !$nt ) return "";
//
//	$name = $nt->getDBkey();
//	$hash = md5( $name );
//
//	$url = "{$wgUploadPath}/thumb/" . $hash{0} . "/" .
//	  substr( $hash, 0, 2 ) . "/{$name}";
//	return wfUrlencode( $url );
//}


function wfImageArchiveUrl( $name )
{
	global $wgUploadPath;

	$hash = md5( substr( $name, 15) );
	$url = "{$wgUploadPath}/archive/" . $hash{0} . "/" .
	  substr( $hash, 0, 2 ) . "/{$name}";
	return wfUrlencode($url);
}

function wfUrlencode ( $s )
{
	$s = urlencode( $s );
	$s = preg_replace( '/%3[Aa]/', ':', $s );
	$s = preg_replace( '/%2[Ff]/', '/', $s );

	return $s;
}

function wfUtf8Sequence($codepoint) {
	if($codepoint <     0x80) return chr($codepoint);
	if($codepoint <    0x800) return chr($codepoint >>  6 & 0x3f | 0xc0) .
                                     chr($codepoint       & 0x3f | 0x80);
    if($codepoint <  0x10000) return chr($codepoint >> 12 & 0x0f | 0xe0) .
                                     chr($codepoint >>  6 & 0x3f | 0x80) .
                                     chr($codepoint       & 0x3f | 0x80);
	if($codepoint < 0x100000) return chr($codepoint >> 18 & 0x07 | 0xf0) . # Double-check this
	                                 chr($codepoint >> 12 & 0x3f | 0x80) .
                                     chr($codepoint >>  6 & 0x3f | 0x80) .
                                     chr($codepoint       & 0x3f | 0x80);
	# Doesn't yet handle outside the BMP
	return "&#$codepoint;";
}

function wfMungeToUtf8($string) {
	global $wgInputEncoding; # This is debatable
	#$string = iconv($wgInputEncoding, "UTF-8", $string);
	$string = preg_replace ( '/&#([0-9]+);/e', 'wfUtf8Sequence($1)', $string );
	$string = preg_replace ( '/&#x([0-9a-f]+);/ie', 'wfUtf8Sequence(0x$1)', $string );
	# Should also do named entities here
	return $string;
}

# Converts a single UTF-8 character into the corresponding HTML character entity
function wfUtf8Entity( $matches ) {
	$char = $matches[0];
	# Find the length
	$z = ord( $char{0} );
	if ( $z & 0x80 ) {
		$length = 0;
		while ( $z & 0x80 ) {
			$length++;
			$z <<= 1;
		}
	} else {
		$length = 1;
	}
	
	if ( $length != strlen( $char ) ) {
		return '';
	}
	if ( $length == 1 ) {
		return $char;
	}

	# Mask off the length-determining bits and shift back to the original location
	$z &= 0xff;
	$z >>= $length;

	# Add in the free bits from subsequent bytes
	for ( $i=1; $i<$length; $i++ ) {
		$z <<= 6;
		$z |= ord( $char{$i} ) & 0x3f;
	}

	# Make entity
	return "&#$z;";
}

# Converts all multi-byte characters in a UTF-8 string into the appropriate character entity
function wfUtf8ToHTML($string) {
	return preg_replace_callback( '/[\\xc0-\\xfd][\\x80-\\xbf]*/', 'wfUtf8Entity', $string );
}

function wfDebug( $text, $logonly = false )
{
	global $wgOut, $wgDebugLogFile, $wgDebugComments, $wgProfileOnly;

	if ( isset( $wgOut ) && $wgDebugComments && !$logonly ) {
		$wgOut->debug( $text );
	}
	if ( "" != $wgDebugLogFile && !$wgProfileOnly ) {
		error_log( $text, 3, $wgDebugLogFile );
	}
}

function logProfilingData()
{
	global $wgRequestTime, $wgDebugLogFile;
	global $wgProfiling, $wgProfileStack, $wgProfileLimit, $wgUser;
	$now = wfTime();

	list( $usec, $sec ) = explode( " ", $wgRequestTime );
	$start = (float)$sec + (float)$usec;
	$elapsed = $now - $start;
	if ( $wgProfiling ) {
		$prof = wfGetProfilingOutput( $start, $elapsed );
		$forward = '';
		if( !empty( $_SERVER['HTTP_X_FORWARDED_FOR'] ) )
			$forward = ' forwarded for ' . $_SERVER['HTTP_X_FORWARDED_FOR'];
		if( !empty( $_SERVER['HTTP_CLIENT_IP'] ) )
			$forward .= ' client IP ' . $_SERVER['HTTP_CLIENT_IP'];
		if( !empty( $_SERVER['HTTP_FROM'] ) )
			$forward .= ' from ' . $_SERVER['HTTP_FROM'];
		if( $forward )
			$forward = "\t(proxied via {$_SERVER['REMOTE_ADDR']}{$forward})";
		if($wgUser->getId() == 0)
			$forward .= ' anon';
		$log = sprintf( "%s\t%04.3f\t%s\n",
		  gmdate( 'YmdHis' ), $elapsed,
		  urldecode( $_SERVER['REQUEST_URI'] . $forward ) );
		if ( '' != $wgDebugLogFile ) {
			error_log( $log . $prof, 3, $wgDebugLogFile );
		}
	}
}


function wfReadOnly()
{
	global $wgReadOnlyFile;

	if ( "" == $wgReadOnlyFile ) { return false; }
	return is_file( $wgReadOnlyFile );
}

$wgReplacementKeys = array( "$1", "$2", "$3", "$4", "$5", "$6", "$7", "$8", "$9" );

# Get a message from anywhere
function wfMsg( $key ) {
	$args = func_get_args();
	if ( count( $args ) ) {
		array_shift( $args );
	}
	return wfMsgReal( $key, $args, true );
}

# Get a message from the language file
function wfMsgNoDB( $key ) {
	$args = func_get_args();
	if ( count( $args ) ) {
		array_shift( $args );
	}
	return wfMsgReal( $key, $args, false );
}

# Really get a message
function wfMsgReal( $key, $args, $useDB ) {
	global $wgReplacementKeys, $wgMessageCache, $wgLang;

	$fname = 'wfMsg';
	wfProfileIn( $fname );
	if ( $wgMessageCache ) {
		$message = $wgMessageCache->get( $key, $useDB );
	} elseif ( $wgLang ) {
		$message = $wgLang->getMessage( $key );
	} else {
		wfDebug( "No language object when getting $key\n" );
		$message = "&lt;$key&gt;";
	}

	# Replace arguments
	if( count( $args ) ) {
		$message = str_replace( $wgReplacementKeys, $args, $message );
	}
	wfProfileOut( $fname );
	return $message;
}

function wfCleanFormFields( $fields )
{
	wfDebugDieBacktrace( 'Call to obsolete wfCleanFormFields(). Use wgRequest instead...' );
}

function wfMungeQuotes( $in )
{
	$out = str_replace( '%', '%25', $in );
	$out = str_replace( "'", '%27', $out );
	$out = str_replace( '"', '%22', $out );
	return $out;
}

function wfDemungeQuotes( $in )
{
	$out = str_replace( '%22', '"', $in );
	$out = str_replace( '%27', "'", $out );
	$out = str_replace( '%25', '%', $out );
	return $out;
}

function wfCleanQueryVar( $var )
{
	wfDebugDieBacktrace( 'Call to obsolete function wfCleanQueryVar(); use wgRequest instead' );
}

function wfSearch( $s )
{
	$se = new SearchEngine( $s );
	$se->showResults();
}

function wfGo( $s )
{ # pick the nearest match
	$se = new SearchEngine( $s );
	$se->goResult();
}

# Just like exit() but makes a note of it.
function wfAbruptExit(){
	static $called = false;
	if ( $called ){
		exit();
	}
	$called = true;

	if( function_exists( 'debug_backtrace' ) ){ // PHP >= 4.3
		$bt = debug_backtrace();
		for($i = 0; $i < count($bt) ; $i++){
			$file = $bt[$i]['file'];
			$line = $bt[$i]['line'];
			wfDebug("WARNING: Abrupt exit in $file at line $line\n");
		}
	} else { 
		wfDebug('WARNING: Abrupt exit\n');
	}
	exit();
}

function wfDebugDieBacktrace( $msg = '' ) {
	$msg .= "\n<p>Backtrace:</p>\n<ul>\n";
	$backtrace = debug_backtrace();
	foreach( $backtrace as $call ) {
		$f = explode( DIRECTORY_SEPARATOR, $call['file'] );
		$file = $f[count($f)-1];
		$msg .= '<li>' . $file . " line " . $call['line'] . ', in ';
		if( !empty( $call['class'] ) ) $msg .= $call['class'] . '::';
		$msg .= $call['function'] . "()</li>\n";
	}
	die( $msg );
}

function wfNumberOfArticles()
{
	global $wgNumberOfArticles;

	wfLoadSiteStats();
	return $wgNumberOfArticles;
}

/* private */ function wfLoadSiteStats()
{
	global $wgNumberOfArticles, $wgTotalViews, $wgTotalEdits;
	if ( -1 != $wgNumberOfArticles ) return;

	$sql = 'SELECT ss_total_views, ss_total_edits, ss_good_articles ' .
	  'FROM site_stats WHERE ss_row_id=1';
	$res = wfQuery( $sql, DB_READ, 'wfLoadSiteStats' );

	if ( 0 == wfNumRows( $res ) ) { return; }
	else {
		$s = wfFetchObject( $res );
		$wgTotalViews = $s->ss_total_views;
		$wgTotalEdits = $s->ss_total_edits;
		$wgNumberOfArticles = $s->ss_good_articles;
	}
}

function wfEscapeHTML( $in )
{
	return str_replace(
		array( '&', '"', '>', '<' ),
		array( '&amp;', '&quot;', '&gt;', '&lt;' ),
		$in );
}

function wfEscapeHTMLTagsOnly( $in ) {
	return str_replace(
		array( '"', '>', '<' ),
		array( '&quot;', '&gt;', '&lt;' ),
		$in );
}

function wfUnescapeHTML( $in )
{
	$in = str_replace( '&lt;', '<', $in );
	$in = str_replace( '&gt;', '>', $in );
	$in = str_replace( '&quot;', '"', $in );
	$in = str_replace( '&amp;', '&', $in );
	return $in;
}

function wfImageDir( $fname )
{
	global $wgUploadDirectory;

	$hash = md5( $fname );
	$oldumask = umask(0);
	$dest = $wgUploadDirectory . '/' . $hash{0};
	if ( ! is_dir( $dest ) ) { mkdir( $dest, 0777 ); }
	$dest .= '/' . substr( $hash, 0, 2 );
	if ( ! is_dir( $dest ) ) { mkdir( $dest, 0777 ); }
	
	umask( $oldumask );
	return $dest;
}

function wfImageThumbDir( $fname , $subdir='thumb')
{
	return wfImageArchiveDir( $fname, $subdir );
}

function wfImageArchiveDir( $fname , $subdir='archive')
{
	global $wgUploadDirectory;

	$hash = md5( $fname );
	$oldumask = umask(0);
	
	# Suppress warning messages here; if the file itself can't
	# be written we'll worry about it then.
	$archive = "{$wgUploadDirectory}/{$subdir}";
	if ( ! is_dir( $archive ) ) { @mkdir( $archive, 0777 ); }
	$archive .= '/' . $hash{0};
	if ( ! is_dir( $archive ) ) { @mkdir( $archive, 0777 ); }
	$archive .= '/' . substr( $hash, 0, 2 );
	if ( ! is_dir( $archive ) ) { @mkdir( $archive, 0777 ); }

	umask( $oldumask );
	return $archive;
}

function wfRecordUpload( $name, $oldver, $size, $desc, $copyStatus = "", $source = "" )
{
	global $wgUser, $wgLang, $wgTitle, $wgOut, $wgDeferredUpdateList;
	global $wgUseCopyrightUpload; 
	
	$fname = 'wfRecordUpload';

	$sql = 'SELECT img_name,img_size,img_timestamp,img_description,img_user,' .
	  "img_user_text FROM image WHERE img_name='" . wfStrencode( $name ) . "'";
	$res = wfQuery( $sql, DB_READ, $fname );

	$now = wfTimestampNow();
	$won = wfInvertTimestamp( $now );
	$size = IntVal( $size );
	
	if ( $wgUseCopyrightUpload )
	  {
	    $textdesc = '== ' . wfMsg ( 'filedesc' ) . " ==\n" . $desc . "\n" .
	      '== ' . wfMsg ( 'filestatus' ) . " ==\n" . $copyStatus . "\n" .
	      '== ' . wfMsg ( 'filesource' ) . " ==\n" . $source ;
	  }
	else $textdesc = $desc ;

	$now = wfTimestampNow();
	$won = wfInvertTimestamp( $now );
	
	if ( 0 == wfNumRows( $res ) ) {
		$sql = 'INSERT INTO image (img_name,img_size,img_timestamp,' .
		  "img_description,img_user,img_user_text) VALUES ('" .
		  wfStrencode( $name ) . "',$size,'{$now}','" .
		  wfStrencode( $desc ) . "', '" . $wgUser->getID() .
		  "', '" . wfStrencode( $wgUser->getName() ) . "')";
		wfQuery( $sql, DB_WRITE, $fname );

		$sql = 'SELECT cur_id,cur_text FROM cur WHERE cur_namespace=' .
		  Namespace::getImage() . " AND cur_title='" .
		  wfStrencode( $name ) . "'";
		$res = wfQuery( $sql, DB_READ, $fname );
		if ( 0 == wfNumRows( $res ) ) {
            $common =
			  Namespace::getImage() . ",'" .
			  wfStrencode( $name ) . "','" .
			  wfStrencode( $desc ) . "','" . $wgUser->getID() . "','" .
			  wfStrencode( $wgUser->getName() ) . "','" . $now .
			  "',1";
			$sql = 'INSERT INTO cur (cur_namespace,cur_title,' .
			  'cur_comment,cur_user,cur_user_text,cur_timestamp,cur_is_new,' .
			  'cur_text,inverse_timestamp,cur_touched) VALUES (' .
			  $common .
			  ",'" . wfStrencode( $textdesc ) . "','{$won}','{$now}')";
			wfQuery( $sql, DB_WRITE, $fname );
			$id = wfInsertId() or 0; # We should throw an error instead
			
			$titleObj = Title::makeTitle( NS_IMAGE, $name );
			RecentChange::notifyNew( $now, $titleObj, 0, $wgUser, $desc );
			
			$u = new SearchUpdate( $id, $name, $desc );
			$u->doUpdate();
		}
	} else {
		$s = wfFetchObject( $res );

		$sql = 'INSERT INTO oldimage (oi_name,oi_archive_name,oi_size,' .
		  "oi_timestamp,oi_description,oi_user,oi_user_text) VALUES ('" .
		  wfStrencode( $s->img_name ) . "','" .
		  wfStrencode( $oldver ) .
		  "',{$s->img_size},'{$s->img_timestamp}','" .
		  wfStrencode( $s->img_description ) . "','" .
		  wfStrencode( $s->img_user ) . "','" .
		  wfStrencode( $s->img_user_text) . "')";
		wfQuery( $sql, DB_WRITE, $fname );

		$sql = "UPDATE image SET img_size={$size}," .
		  "img_timestamp='" . wfTimestampNow() . "',img_user='" .
		  $wgUser->getID() . "',img_user_text='" .
		  wfStrencode( $wgUser->getName() ) . "', img_description='" .
		  wfStrencode( $desc ) . "' WHERE img_name='" .
		  wfStrencode( $name ) . "'";
		wfQuery( $sql, DB_WRITE, $fname );
		
		$sql = "UPDATE cur SET cur_touched='{$now}' WHERE cur_namespace=" .
		  Namespace::getImage() . " AND cur_title='" .
		  wfStrencode( $name ) . "'";
		wfQuery( $sql, DB_WRITE, $fname );
	}

	$log = new LogPage( wfMsg( 'uploadlogpage' ), wfMsg( 'uploadlogpagetext' ) );
	$da = wfMsg( 'uploadedimage', '[[:' . $wgLang->getNsText(
	  Namespace::getImage() ) . ":{$name}|{$name}]]" );
	$ta = wfMsg( 'uploadedimage', $name );
	$log->addEntry( $da, $desc, $ta );
}


/* Some generic result counters, pulled out of SearchEngine */

function wfShowingResults( $offset, $limit )
{
	global $wgLang;
	return wfMsg( 'showingresults', $wgLang->formatNum( $limit ), $wgLang->formatNum( $offset+1 ) );
}

function wfShowingResultsNum( $offset, $limit, $num )
{
	global $wgLang;
	return wfMsg( 'showingresultsnum', $wgLang->formatNum( $limit ), $wgLang->formatNum( $offset+1 ), $wgLang->formatNum( $num ) );
}

function wfViewPrevNext( $offset, $limit, $link, $query = '', $atend = false )
{
	global $wgUser, $wgLang;
	$fmtLimit = $wgLang->formatNum( $limit );
	$prev = wfMsg( 'prevn', $fmtLimit );
	$next = wfMsg( 'nextn', $fmtLimit );
	$link = wfUrlencode( $link );

	$sk = $wgUser->getSkin();
	if ( 0 != $offset ) {
		$po = $offset - $limit;
		if ( $po < 0 ) { $po = 0; }
		$q = "limit={$limit}&offset={$po}";
		if ( '' != $query ) { $q .= "&{$query}"; }
		$plink = '<a href="' . wfLocalUrlE( $link, $q ) . "\">{$prev}</a>";
	} else { $plink = $prev; }

	$no = $offset + $limit;
	$q = "limit={$limit}&offset={$no}";
	if ( "" != $query ) { $q .= "&{$query}"; }

	if ( $atend ) {
		$nlink = $next;
	} else {
		$nlink = '<a href="' . wfLocalUrlE( $link, $q ) . "\">{$next}</a>";
	}
	$nums = wfNumLink( $offset, 20, $link , $query ) . ' | ' .
	  wfNumLink( $offset, 50, $link, $query ) . ' | ' .
	  wfNumLink( $offset, 100, $link, $query ) . ' | ' .
	  wfNumLink( $offset, 250, $link, $query ) . ' | ' .
	  wfNumLink( $offset, 500, $link, $query );

	return wfMsg( 'viewprevnext', $plink, $nlink, $nums );
}

function wfNumLink( $offset, $limit, $link, $query = '' )
{
	global $wgUser, $wgLang;
	if ( '' == $query ) { $q = ''; }
	else { $q = "{$query}&"; }
	$q .= "limit={$limit}&offset={$offset}";

	$fmtLimit = $wgLang->formatNum( $limit );
	$s = '<a href="' . wfLocalUrlE( $link, $q ) . "\">{$fmtLimit}</a>";
	return $s;
}

function wfClientAcceptsGzip() {
	global $wgUseGzip;
	if( $wgUseGzip ) {
		# FIXME: we may want to blacklist some broken browsers
		if( preg_match(
			'/\bgzip(?:;(q)=([0-9]+(?:\.[0-9]+)))?\b/',
			$_SERVER['HTTP_ACCEPT_ENCODING'],
			$m ) ) {
			if( ( $m[1] == 'q' ) && ( $m[2] == 0 ) ) return false;
			wfDebug( " accepts gzip\n" );
			return true;
		}
	}
	return false;
}

# Yay, more global functions!
function wfCheckLimits( $deflimit = 50, $optionname = 'rclimit' ) {
	global $wgUser, $wgRequest;
	
	$limit = $wgRequest->getInt( 'limit', 0 );
	if( $limit < 0 ) $limit = 0;
	if( ( $limit == 0 ) && ( $optionname != '' ) ) {
		$limit = (int)$wgUser->getOption( $optionname );
	}
	if( $limit <= 0 ) $limit = $deflimit;
	if( $limit > 5000 ) $limit = 5000; # We have *some* limits...
	
	$offset = $wgRequest->getInt( 'offset', 0 );
	if( $offset < 0 ) $offset = 0;
	if( $offset > 65000 ) $offset = 65000; # do we need a max? what?
	
	return array( $limit, $offset );
}

# Escapes the given text so that it may be output using addWikiText() 
# without any linking, formatting, etc. making its way through. This 
# is achieved by substituting certain characters with HTML entities.
# As required by the callers, <nowiki> is not used. It currently does
# not filter out characters which have special meaning only at the
# start of a line, such as "*".
function wfEscapeWikiText( $text )
{
	$text = str_replace( 
		array( '[',     '|',      "'",     'ISBN '    , '://'     , "\n=" ),
		array( '&#91;', '&#124;', '&#39;', 'ISBN&#32;', '&#58;//' , "\n&#61;" ),
		htmlspecialchars($text) );
	return $text;
}

function wfQuotedPrintable( $string, $charset = '' ) 
{
	# Probably incomplete; see RFC 2045
	if( empty( $charset ) ) {
		global $wgInputEncoding;
		$charset = $wgInputEncoding;
	}
	$charset = strtoupper( $charset );
	$charset = str_replace( 'ISO-8859', 'ISO8859', $charset ); // ?

	$illegal = '\x00-\x08\x0b\x0c\x0e-\x1f\x7f-\xff=';
	$replace = $illegal . '\t ?_';
	if( !preg_match( "/[$illegal]/", $string ) ) return $string;
	$out = "=?$charset?Q?";
	$out .= preg_replace( "/([$replace])/e", 'sprintf("=%02X",ord("$1"))', $string );
	$out .= '?=';
	return $out;
}

function wfTime(){
	$st = explode( ' ', microtime() );
	return (float)$st[0] + (float)$st[1];
}

# Changes the first character to an HTML entity
function wfHtmlEscapeFirst( $text ) {
	$ord = ord($text);
	$newText = substr($text, 1);
	return "&#$ord;$newText";
}

# Sets dest to source and returns the original value of dest
function wfSetVar( &$dest, $source )
{
	$temp = $dest;
	$dest = $source;
	return $temp;
}

# Sets dest to a reference to source and returns the original dest
function &wfSetRef( &$dest, &$source )
{
	$temp =& $dest;
	$dest =& $source;
	return $temp;
}

# This function takes two arrays as input, and returns a CGI-style string, e.g.
# "days=7&limit=100". Options in the first array override options in the second.
# Options set to "" will not be output.
function wfArrayToCGI( $array1, $array2 = NULL ) 
{
	if ( !is_null( $array2 ) ) {
		$array1 = $array1 + $array2;
	}

	$cgi = '';
	foreach ( $array1 as $key => $value ) {
		if ( '' !== $value ) {
			if ( '' != $cgi ) {
				$cgi .= '&';
			}
			$cgi .= "{$key}={$value}";
		}
	}
	return $cgi;
}

# This is obsolete, use SquidUpdate::purge()
function wfPurgeSquidServers ($urlArr) {
	SquidUpdate::purge( $urlArr );
}

# Windows-compatible version of escapeshellarg()
function wfEscapeShellArg( )
{
	$args = func_get_args();
	$first = true;
	$retVal = '';
	foreach ( $args as $arg ) {
		if ( !$first ) { 
			$retVal .= ' ';
		} else {
			$first = false;
		}

		if (substr(php_uname(), 0, 7) == 'Windows') {
			$retVal .= '"' . str_replace( '"','\"', $arg ) . '"';
		} else {
			$retVal .= escapeshellarg( $arg );
		}
	}
	return $retVal;
}

# wfMerge attempts to merge differences between three texts. 
# Returns true for a clean merge and false for failure or a conflict.

function wfMerge( $old, $mine, $yours, &$result ){
	global $wgDiff3;

	# This check may also protect against code injection in 
	# case of broken installations.
	if(! file_exists( $wgDiff3 ) ){ 
		return false;
	}

	# Make temporary files
	$td = '/tmp/';
	$oldtextFile = fopen( $oldtextName = tempnam( $td, 'merge-old-' ), 'w' );
	$mytextFile = fopen( $mytextName = tempnam( $td, 'merge-mine-' ), 'w' );
	$yourtextFile = fopen( $yourtextName = tempnam( $td, 'merge-your-' ), 'w' );
			
	fwrite( $oldtextFile, $old ); fclose( $oldtextFile ); 
	fwrite( $mytextFile, $mine ); fclose( $mytextFile ); 
	fwrite( $yourtextFile, $yours ); fclose( $yourtextFile );

	# Check for a conflict
    $cmd = wfEscapeShellArg( $wgDiff3 ) . ' -a --overlap-only ' .
      wfEscapeShellArg( $mytextName ) . ' ' .
      wfEscapeShellArg( $oldtextName ) . ' ' .
      wfEscapeShellArg( $yourtextName );
    $handle = popen( $cmd, 'r' );

	if( fgets( $handle ) ){
		$conflict = true;
	} else {
		$conflict = false;
	}
	pclose( $handle );

	# Merge differences
	$cmd = wfEscapeShellArg( $wgDiff3 ) . ' -a -e --merge ' . 
	  wfEscapeShellArg( $mytextName, $oldtextName, $yourtextName );
	$handle = popen( $cmd, 'r' );
	$result = '';
	do {
		$data = fread( $handle, 8192 );
		if ( strlen( $data ) == 0 ) {
			break;
		}
		$result .= $data;
	} while ( true );
	pclose( $handle );
	unlink( $mytextName ); unlink( $oldtextName ); unlink( $yourtextName );
	return ! $conflict;
}

function wfVarDump( $var )
{
	global $wgOut;
	$s = str_replace("\n","<br>\n", var_export( $var, true ) . "\n");
	if ( headers_sent() || !@is_object( $wgOut ) ) {
		print $s;
	} else {
		$wgOut->addHTML( $s );
	}
}

# Provide a simple HTTP error.
function wfHttpError( $code, $label, $desc ) {
	global $wgOut;
	$wgOut->disable();
	header( "HTTP/1.0 $code $label" );
	header( "Status: $code $label" );
	$wgOut->sendCacheControl();
	
	# Don't send content if it's a HEAD request.
	if( $_SERVER['REQUEST_METHOD'] == 'HEAD' ) {
		header( 'Content-type: text/plain' );
		print "$desc\n";
	}
}

# Converts an Accept-* header into an array mapping string values to quality factors
function wfAcceptToPrefs( $accept, $def = '*/*' ) {
	# No arg means accept anything (per HTTP spec)
	if( !$accept ) {
		return array( $def => 1 );
	}
	
	$prefs = array();
	
	$parts = explode( ',', $accept );
	
	foreach( $parts as $part ) {
		# FIXME: doesn't deal with params like 'text/html; level=1'
		@list( $value, $qpart ) = explode( ';', $part );
		if( !isset( $qpart ) ) {
			$prefs[$value] = 1;
		} elseif( preg_match( '/q\s*=\s*(\d*\.\d+)/', $qpart, $match ) ) {
			$prefs[$value] = $match[1];
		}
	}
	
	return $prefs;
}

/* private */ function mimeTypeMatch( $type, $avail ) {
	if( array_key_exists($type, $avail) ) {
		return $type;
	} else {
		$parts = explode( '/', $type );
		if( array_key_exists( $parts[0] . '/*', $avail ) ) {
			return $parts[0] . '/*';
		} elseif( array_key_exists( '*/*', $avail ) ) {
			return '*/*';
		} else {
			return NULL;
		}
	}
}

# FIXME: doesn't handle params like 'text/plain; charset=UTF-8'
# XXX: generalize to negotiate other stuff
function wfNegotiateType( $cprefs, $sprefs ) {
	$combine = array();
	
	foreach( array_keys($sprefs) as $type ) {
		$parts = explode( '/', $type );
		if( $parts[1] != '*' ) {
			$ckey = mimeTypeMatch( $type, $cprefs );
			if( $ckey ) {
				$combine[$type] = $sprefs[$type] * $cprefs[$ckey];
			}
		}
	}
	
	foreach( array_keys( $cprefs ) as $type ) {
		$parts = explode( '/', $type );
		if( $parts[1] != '*' && !array_key_exists( $type, $sprefs ) ) {
			$skey = mimeTypeMatch( $type, $sprefs );
			if( $skey ) {
				$combine[$type] = $sprefs[$skey] * $cprefs[$type];
			}
		}
	}
	
	$bestq = 0;
	$besttype = NULL;
	
	foreach( array_keys( $combine ) as $type ) {
		if( $combine[$type] > $bestq ) {
			$besttype = $type;
			$bestq = $combine[$type];
		}
	}
	
	return $besttype;
}

# Array lookup
# Returns an array where the values in the first array are replaced by the 
# values in the second array with the corresponding keys
function wfArrayLookup( $a, $b )
{
	return array_flip( array_intersect( array_flip( $a ), array_keys( $b ) ) ); 
}

?>