class.ilUtil.php

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<?php
/* Copyright (c) 1998-2010 ILIAS open source, Extended GPL, see docs/LICENSE */

use ILIAS\Filesystem\Util\LegacyPathHelper;
use ILIAS\FileUpload\DTO\ProcessingStatus;
use ILIAS\Filesystem\MetadataType;

class ilUtil
{
    protected static $db_supports_distinct_umlauts;

    public static function getImageTagByType($a_type, $a_path, $a_big = false)
    {
        global $DIC;

        $lng = $DIC->language();

        $size = ($a_big)
            ? "big"
            : "small";

        include_once("./Services/Object/classes/class.ilObject.php");
        $filename = ilObject::_getIcon("", $size, $a_type);

        return "<img src=\"" . $filename . "\" alt=\"" . $lng->txt("obj_" . $a_type) . "\" title=\"" . $lng->txt("obj_" . $a_type) . "\" border=\"0\" vspace=\"0\"/>";
    }

    public static function getTypeIconPath($a_type, $a_obj_id, $a_size = 'small')
    {
        include_once("./Services/Object/classes/class.ilObject.php");
        return ilObject::_getIcon($a_obj_id, $a_size, $a_type);
    }

    public static function getImagePath($img, $module_path = "", $mode = "output", $offline = false)
    {
        global $DIC;

        $styleDefinition = null;
        if (isset($DIC["styleDefinition"])) {
            $styleDefinition = $DIC["styleDefinition"];
        }

        if (is_int(strpos($_SERVER["PHP_SELF"], "setup.php"))) {
            $module_path = "..";
        }
        if ($module_path != "") {
            $module_path = "/" . $module_path;
        }

        // default image
        $default_img = "." . $module_path . "/templates/default/images/" . $img;

        // use ilStyleDefinition instead of account to get the current skin and style
        require_once("./Services/Style/System/classes/class.ilStyleDefinition.php");
        $current_skin = ilStyleDefinition::getCurrentSkin();
        $current_style = ilStyleDefinition::getCurrentStyle();
        
        if (is_object($styleDefinition)) {
            $image_dir = $styleDefinition->getImageDirectory($current_style);
        }
        if ($current_skin == "default") {
            $user_img = "." . $module_path . "/templates/default/" . $image_dir . "/" . $img;
            $skin_img = "." . $module_path . "/templates/default/images/" . $img;
        } elseif (is_object($styleDefinition) && $current_skin != "default") {
            $user_img = "./Customizing/global/skin/" .
                $current_skin . $module_path . "/" . $image_dir . "/" . $img;
            $skin_img = "./Customizing/global/skin/" .
                $current_skin . $module_path . "/images/" . $img;
        }

        // temp svg patch
        /*
        $pi = pathinfo($img);
        if ($pi["dirname"] != "") {
            $pi["dirname"] = $pi["dirname"]."/";
        }
        $svg_img = ".".$module_path."/templates/default/images/".$pi["dirname"].$pi["filename"].".svg";
        if (file_exists($svg_img))
        {
            return $svg_img;
        }*/


        if ($offline) {
            return "./images/" . $img;
        } elseif (@file_exists($user_img) && $image_dir != "") {
            return $user_img;           // found image for skin and style
        } elseif (file_exists($skin_img)) {
            return $skin_img;           // found image in skin/images
        }

        return $default_img;                    // take image in default
    }

    public static function getHtmlPath($relative_path)
    {
        if (substr($relative_path, 0, 2) == './') {
            $relative_path = (substr($relative_path, 1));
        }
        if (substr($relative_path, 0, 1) != '/') {
            $relative_path = '/' . $relative_path;
        }
        $htmlpath = ILIAS_HTTP_PATH . $relative_path;
        return $htmlpath;
    }

    public static function getStyleSheetLocation($mode = "output", $a_css_name = "", $a_css_location = "")
    {
        global $DIC;

        $ilSetting = $DIC->settings();
        
        // add version as parameter to force reload for new releases
        // use ilStyleDefinition instead of account to get the current style
        require_once("./Services/Style/System/classes/class.ilStyleDefinition.php");
        $stylesheet_name = (strlen($a_css_name))
            ? $a_css_name
            : ilStyleDefinition::getCurrentStyle() . ".css";
        if (strlen($a_css_location) && (strcmp(substr($a_css_location, -1), "/") != 0)) {
            $a_css_location = $a_css_location . "/";
        }

        $filename = "";
        // use ilStyleDefinition instead of account to get the current skin
        require_once("./Services/Style/System/classes/class.ilStyleDefinition.php");
        if (ilStyleDefinition::getCurrentSkin() != "default") {
            $filename = "./Customizing/global/skin/" . ilStyleDefinition::getCurrentSkin() . "/" . $a_css_location . $stylesheet_name;
        }
        if (strlen($filename) == 0 || !file_exists($filename)) {
            $filename = "./" . $a_css_location . "templates/default/" . $stylesheet_name;
        }
        $vers = "";
        if ($mode != "filesystem") {
            $vers = str_replace(" ", "-", $ilSetting->get("ilias_version"));
            $vers = "?vers=" . str_replace(".", "-", $vers);
            // use version from template xml to force reload on changes
            $skin = ilStyleDefinition::getSkins()[ilStyleDefinition::getCurrentSkin()];
            $vers .= ($skin->getVersion() != '' ? str_replace(".", "-", '-' . $skin->getVersion()) : '');
        }
        return $filename . $vers;
    }

    public static function getJSLocation($a_js_name, $a_js_location = "", $add_version = false)
    {
        global $DIC;

        $ilSetting = $DIC->settings();

        // add version as parameter to force reload for new releases
        $js_name = $a_js_name;
        if (strlen($a_js_location) && (strcmp(substr($a_js_location, -1), "/") != 0)) {
            $a_js_location = $a_js_location . "/";
        }

        $filename = "";
        // use ilStyleDefinition instead of account to get the current skin
        require_once("./Services/Style/System/classes/class.ilStyleDefinition.php");
        if (ilStyleDefinition::getCurrentSkin() != "default") {
            $filename = "./Customizing/global/skin/" . ilStyleDefinition::getCurrentSkin() . "/" . $a_js_location . $js_name;
        }
        if (strlen($filename) == 0 || !file_exists($filename)) {
            $filename = "./" . $a_js_location . "templates/default/" . $js_name;
        }
        $vers = "";
        if ($add_version) {
            $vers = str_replace(" ", "-", $ilSetting->get("ilias_version"));
            $vers = "?vers=" . str_replace(".", "-", $vers);
        }
        return $filename . $vers;
    }

    public static function getP3PLocation()
    {
        if (defined("ILIAS_MODULE")) {
            $base = '';
            for ($i = 0;$i < count(explode('/', ILIAS_MODULE));$i++) {
                $base .= "../Services/Privacy/";
            }
        } else {
            $base = "./Services/Privacy/";
        }

        if (is_file($base . "w3c/p3p.xml")) {
            return ILIAS_HTTP_PATH . "w3c/p3p.xml";
        } else {
            return ILIAS_HTTP_PATH . "/w3c/p3p_template.xml";
        }
    }

    public static function getNewContentStyleSheetLocation($mode = "output")
    {
        global $DIC;

        $ilSetting = $DIC->settings();

        // add version as parameter to force reload for new releases
        if ($mode != "filesystem") {
            $vers = str_replace(" ", "-", $ilSetting->get("ilias_version"));
            $vers = "?vers=" . str_replace(".", "-", $vers);
        }

        // use ilStyleDefinition instead of account to get the current skin and style
        require_once("./Services/Style/System/classes/class.ilStyleDefinition.php");
        if (ilStyleDefinition::getCurrentSkin() == "default") {
            $in_style = "./templates/" . ilStyleDefinition::getCurrentSkin() . "/"
                                    . ilStyleDefinition::getCurrentStyle() . "_cont.css";
        } else {
            $in_style = "./Customizing/global/skin/" . ilStyleDefinition::getCurrentSkin() . "/"
                                                    . ilStyleDefinition::getCurrentStyle() . "_cont.css";
        }

        if (is_file("./" . $in_style)) {
            return $in_style . $vers;
        } else {
            return "templates/default/delos_cont.css" . $vers;
        }
    }

    public static function formSelect(
        $selected,
        $varname,
        $options,
        $multiple = false,
        $direct_text = false,
        $size = "0",
        $style_class = "",
        $attribs = "",
        $disabled = false
    ) {
        global $DIC;

        $lng = $DIC->language();

        if ($multiple == true) {
            $multiple = " multiple=\"multiple\"";
        } else {
            $multiple = "";
            $size = 0;
        }

        $class = " class=\" form-control " . $style_class . "\"";

        // use form-inline!
        // this is workaround the whole function should be set deprecated
        // $attributes = " style='display:inline-block;' ";

        if (is_array($attribs)) {
            foreach ($attribs as $key => $val) {
                $attributes .= " " . $key . "=\"" . $val . "\"";
            }
        }
        if ($disabled) {
            $disabled = ' disabled=\"disabled\"';
        }

        $str = "<select name=\"" . $varname . "\"" . $multiple . " $class size=\"" . $size . "\" $attributes $disabled>\n";

        foreach ((array) $options as $key => $val) {
            $style = "";
            if (is_array($val)) {
                $style = $val["style"];
                $val = $val["text"];            // mus be last line, since we overwrite
            }

            $sty = ($style != "")
                ? ' style="' . $style . '" '
                : "";
                
            if ($direct_text) {
                $str .= " <option $sty value=\"" . $key . "\"";
            } else {
                $str .= " <option $sty value=\"" . $val . "\"";
            }
            if (is_array($selected)) {
                if (in_array($key, $selected)) {
                    $str .= " selected=\"selected\"";
                }
            } elseif ($selected == $key) {
                $str .= " selected=\"selected\"";
            }

            if ($direct_text) {
                $str .= ">" . $val . "</option>\n";
            } else {
                $str .= ">" . $lng->txt($val) . "</option>\n";
            }
        }

        $str .= "</select>\n";

        return $str;
    }

    public static function getSelectName($selected, $values)
    {
        return($values[$selected]);
    }

    public static function formCheckbox($checked, $varname, $value, $disabled = false)
    {
        $str = "<input type=\"checkbox\" name=\"" . $varname . "\"";

        if ($checked == 1) {
            $str .= " checked=\"checked\"";
        }

        if ($disabled) {
            $str .= " disabled=\"disabled\"";
        }

        $array_var = false;

        if (substr($varname, -2) == "[]") {
            $array_var = true;
        }

        // if varname ends with [], use varname[-2] + _ + value as id tag (e.g. "user_id[]" => "user_id_15")
        if ($array_var) {
            $varname_id = substr($varname, 0, -2) . "_" . $value;
        } else {
            $varname_id = $varname;
        }

        // dirty removal of other "[]" in string
        $varname_id = str_replace("[", "_", $varname_id);
        $varname_id = str_replace("]", "", $varname_id);

        $str .= " value=\"" . $value . "\" id=\"" . $varname_id . "\" />\n";

        return $str;
    }

    public static function formDisabledRadioButton($checked, $varname, $value, $disabled)
    {
        if ($disabled) {
            $str = "<input disabled type=\"radio\" name=\"" . $varname . "\"";
        } else {
            $str = "<input type=\"radio\" name=\"" . $varname . "\"";
        }
        if ($checked == 1) {
            $str .= " checked=\"checked\"";
        }

        $str .= " value=\"" . $value . "\"";
        $str .= " id=\"" . $value . "\" />\n";

        return $str;
    }


    public static function formRadioButton($checked, $varname, $value, $onclick=null, $disabled = false)
    {
        $str = '<input ';

        if ($onclick) {
            $str .= ('onclick="' . $onclick . '"');
        }
        
        $str .= (" type=\"radio\" name=\"" . $varname . "\"");
        if ($checked == 1) {
            $str .= " checked=\"checked\"";
        }

        if ($disabled) {
            $str .= " disabled=\"disabled\"";
        }

        $str .= " value=\"" . $value . "\"";

        $str .= " id=\"" . $value . "\" />\n";

        return $str;
    }


    public static function formInput($varname, $value, $disabled = false)
    {
        $str = "<input type=\"input\" name=\"" . $varname . "\"";
        if ($disabled) {
            $str .= " disabled";
        }

        $str .= " value=\"" . $value . "\"";

        $str .= " id=\"" . $value . "\" />\n";

        return $str;
    }


    public static function checkInput($vars)
    {
        // TO DO:
        // Diese Funktion soll Formfeldeingaben berprfen (empty und required)
    }

    public static function setPathStr($a_path)
    {
        if ("" != $a_path && "/" != substr($a_path, -1)) {
            $a_path .= "/";
            //$a_path = substr($a_path,1);
        }

        //return getcwd().$a_path;
        return $a_path;
    }

    public static function switchColor($a_num, $a_css1, $a_css2)
    {
        if (!($a_num % 2)) {
            return $a_css1;
        } else {
            return $a_css2;
        }
    }

    public static function checkFormEmpty($emptyFields)
    {
        $feedback = "";

        foreach ($emptyFields as $key => $val) {
            if ($val == "") {
                if ($feedback != "") {
                    $feedback .= ", ";
                }
                $feedback .= $key;
            }
        }

        return $feedback;
    }

    public static function Linkbar($AScript, $AHits, $ALimit, $AOffset, $AParams = array(), $ALayout = array(), $prefix = '')
    {
        $LinkBar = "";

        $layout_link = "";
        $layout_prev = "&lt;&lt;";
        $layout_next = "&gt;&gt;";

        // layout options
        if ((is_array($ALayout) && (count($ALayout) > 0))) {
            if ($ALayout["link"]) {
                $layout_link = " class=\"" . $ALayout["link"] . "\"";
            }

            if ($ALayout["prev"]) {
                $layout_prev = $ALayout["prev"];
            }

            if ($ALayout["next"]) {
                $layout_next = $ALayout["next"];
            }
        }

        // show links, if hits greater limit
        // or offset > 0 (can be > 0 due to former setting)
        if ($AHits > $ALimit || $AOffset > 0) {
            if (!empty($AParams)) {
                foreach ($AParams as $key => $value) {
                    $params.= $key . "=" . $value . "&";
                }
            }
            // if ($params) $params = substr($params,0,-1);
            if (strpos($AScript, '&')) {
                $link = $AScript . "&" . $params . $prefix . "offset=";
            } else {
                $link = $AScript . "?" . $params . $prefix . "offset=";
            }

            // ?bergehe "zurck"-link, wenn offset 0 ist.
            if ($AOffset >= 1) {
                $prevoffset = $AOffset - $ALimit;
                if ($prevoffset < 0) {
                    $prevoffset = 0;
                }
                $LinkBar .= "<a" . $layout_link . " href=\"" . $link . $prevoffset . "\">" . $layout_prev . "&nbsp;</a>";
            }

            // Ben?tigte Seitenzahl kalkulieren
            $pages=intval($AHits/$ALimit);

            // Wenn ein Rest bleibt, addiere eine Seite
            if (($AHits % $ALimit)) {
                $pages++;
            }

            // Bei Offset = 0 keine Seitenzahlen anzeigen : DEAKTIVIERT
            //                  if ($AOffset != 0) {

            // ansonsten zeige Links zu den anderen Seiten an
            for ($i = 1 ;$i <= $pages ; $i++) {
                $newoffset=$ALimit*($i-1);

                if ($newoffset == $AOffset) {
                    $LinkBar .= "[" . $i . "] ";
                } else {
                    $LinkBar .= '<a ' . $layout_link . ' href="' .
                        $link . $newoffset . '">[' . $i . ']</a> ';
                }
            }
            //                  }

            // Checken, ob letze Seite erreicht ist
            // Wenn nicht, gebe einen "Weiter"-Link aus
            if (!(($AOffset/$ALimit)==($pages-1)) && ($pages!=1)) {
                $newoffset=$AOffset+$ALimit;
                $LinkBar .= "<a" . $layout_link . " href=\"" . $link . $newoffset . "\">&nbsp;" . $layout_next . "</a>";
            }

            return $LinkBar;
        } else {
            return false;
        }
    }

    public static function makeClickable($a_text, $detectGotoLinks = false)
    {
        // New code, uses MediaWiki Sanitizer
        $ret = $a_text;

        // www-URL ohne ://-Angabe
        $ret = preg_replace(
            "/(^|[\s]+)(www\.)([A-Za-z0-9#&=?.\/\-]+)/i",
            "$1http://$2$3",
            $ret
        );

        // ftp-URL ohne ://-Angabe
        $ret = preg_replace(
            "/(^|[\s]+)(ftp\.)([A-Za-z0-9#&=?.\/\-]+)/i",
            "$1ftp://$2$3",
            $ret
        );

        // E-Mail (this does not work as expected, users must add mailto: manually)
        //$ret = preg_replace("/(([a-z0-9_]|\-|\.)+@([^[\s]*)([A-Za-z0-9\-]))/i",
        //      "mailto:$1", $ret);

        // mask existing image tags
        $ret = str_replace('src="http://', '"***masked_im_start***', $ret);
        
        include_once("./Services/Utilities/classes/class.ilMWParserAdapter.php");
        $parser = new ilMWParserAdapter();
        $ret = $parser->replaceFreeExternalLinks($ret);

        // unmask existing image tags
        $ret = str_replace('"***masked_im_start***', 'src="http://', $ret);

        // Should be Safe

        if ($detectGotoLinks) {
            // replace target blank with self and text with object title.
            $regExp = "<a[^>]*href=\"(" . str_replace("/", "\/", ILIAS_HTTP_PATH) . "\/goto.php\?target=\w+_(\d+)[^\"]*)\"[^>]*>[^<]*<\/a>";
            //                  echo htmlentities($regExp);
            $ret = preg_replace_callback(
                "/" . $regExp . "/i",
                array("ilUtil", "replaceLinkProperties"),
                $ret
            );

            // Static links
            $regExp = "<a[^>]*href=\"(" . str_replace("/", "\/", ILIAS_HTTP_PATH) . "\/goto_.*[a-z0-9]+_([0-9]+)\.html)\"[^>]*>[^<]*<\/a>";
            //                  echo htmlentities($regExp);
            $ret = preg_replace_callback(
                "/" . $regExp . "/i",
                array("ilUtil", "replaceLinkProperties"),
                $ret
            );
        }

        return($ret);
    }

    public static function replaceLinkProperties($matches)
    {
        $link = $matches[0];
        $ref_id = $matches[2];

        if ($ref_id > 0) {
            $obj_id = ilObject::_lookupObjId($ref_id);
            if ($obj_id > 0) {
                $title = ilObject::_lookupTitle($obj_id);
                $link = "<a href=" . $matches[1] . " target=\"_self\">" . $title . "</a>";
            }
        }
        return $link;
    }

    public static function makeDateSelect($prefix, $year = "", $month = "", $day = "", $startyear = "", $a_long_month = true, $a_further_options = array(), $emptyoption = false)
    {
        global $DIC;

        $lng = $DIC->language();

        $disabled = '';
        if (isset($a_further_options['disabled']) and $a_further_options['disabled']) {
            $disabled = 'disabled="disabled" ';
        }

        $now = getdate();
        if (!$emptyoption) {
            if (!strlen($year)) {
                $year = $now["year"];
            }
            if (!strlen($month)) {
                $month = $now["mon"];
            }
            if (!strlen($day)) {
                $day = $now["mday"];
            }
        }

        $year = (int) $year;
        $month = (int) $month;
        $day = (int) $day;

        // build day select

        $sel_day .= '<select class="form-control" ';
        if (isset($a_further_options['select_attributes'])) {
            foreach ($a_further_options['select_attributes'] as $name => $value) {
                $sel_day .= ($name . '="' . $value . '" ');
            }
        }
        
        $sel_day .= $disabled . "name=\"" . $prefix . "[d]\" id=\"" . $prefix . "_d\">\n";
        
        if ($emptyoption) {
            $sel_day .= "<option value=\"0\">--</option>\n";
        }
        for ($i = 1; $i <= 31; $i++) {
            $sel_day .= "<option value=\"$i\">" . sprintf("%02d", $i) . "</option>\n";
        }
        $sel_day .= "</select>\n";
        $sel_day = preg_replace("/(value\=\"$day\")/", "$1 selected=\"selected\"", $sel_day);

        // build month select
        $sel_month = '<select class="form-control" ';
        if (isset($a_further_options['select_attributes'])) {
            foreach ($a_further_options['select_attributes'] as $name => $value) {
                $sel_month .= ($name . '="' . $value . '" ');
            }
        }
        $sel_month .= $disabled . "name=\"" . $prefix . "[m]\" id=\"" . $prefix . "_m\">\n";

        if ($emptyoption) {
            $sel_month .= "<option value=\"0\">--</option>\n";
        }
        for ($i = 1; $i <= 12; $i++) {
            if ($a_long_month) {
                $sel_month .= "<option value=\"$i\">" . $lng->txt("month_" . sprintf("%02d", $i) . "_long") . "</option>\n";
            } else {
                $sel_month .= "<option value=\"$i\">" . $i . "</option>\n";
            }
        }
        $sel_month .= "</select>\n";
        $sel_month = preg_replace("/(value\=\"$month\")/", "$1 selected=\"selected\"", $sel_month);

        // build year select
        $sel_year = '<select class="form-control" ';
        if (isset($a_further_options['select_attributes'])) {
            foreach ($a_further_options['select_attributes'] as $name => $value) {
                $sel_year .= ($name . '="' . $value . '" ');
            }
        }
        $sel_year .= $disabled . "name=\"" . $prefix . "[y]\" id=\"" . $prefix . "_y\">\n";
        if ((strlen($startyear) == 0) || ($startyear > $year)) {
            if (!$emptyoption || $year != 0) {
                $startyear = $year - 5;
            }
        }

        if (($year + 5) < (date('Y', time()) + 5)) {
            $end_year = date('Y', time()) + 5;
        } else {
            $end_year = $year + 5;
        }

        if ($emptyoption) {
            $sel_year .= "<option value=\"0\">----</option>\n";
        }
        for ($i = $startyear; $i <= $end_year; $i++) {
            $sel_year .= "<option value=\"$i\">" . sprintf("%04d", $i) . "</option>\n";
        }
        $sel_year .= "</select>\n";
        $sel_year = preg_replace("/(value\=\"$year\")/", "$1 selected=\"selected\"", $sel_year);

        //$dateformat = $lng->text["lang_dateformat"];
        $dateformat = "d-m-Y";
        $dateformat = strtolower(preg_replace("/\W/", "", $dateformat));
        $dateformat = strtolower(preg_replace("/(\w)/", "%%$1", $dateformat));
        $dateformat = preg_replace("/%%d/", $sel_day, $dateformat);
        $dateformat = preg_replace("/%%m/", $sel_month, $dateformat);
        $dateformat = preg_replace("/%%y/", $sel_year, $dateformat);
        return $dateformat;
    }

    public static function makeTimeSelect($prefix, $short = true, $hour = "", $minute = "", $second = "", $a_use_default = true, $a_further_options = array())
    {
        global $DIC;

        $lng = $DIC->language();
        $ilUser = $DIC->user();

        $minute_steps = 1;
        $disabled = '';
        if (count($a_further_options)) {
            if (isset($a_further_options['minute_steps'])) {
                $minute_steps = $a_further_options['minute_steps'];
            }
            if (isset($a_further_options['disabled']) and $a_further_options['disabled']) {
                $disabled = 'disabled="disabled" ';
            }
        }

        if ($a_use_default and !strlen("$hour$minute$second")) {
            $now = localtime();
            $hour = $now[2];
            $minute = $now[1];
            $second = $now[0];
        } else {
            $hour = (int) $hour;
            $minute = (int) $minute;
            $second = (int) $second;
        }
        // build hour select
        $sel_hour = '<select ';
        if (isset($a_further_options['select_attributes'])) {
            foreach ($a_further_options['select_attributes'] as $name => $value) {
                $sel_hour .= $name . '=' . $value . ' ';
            }
        }
        $sel_hour .= " " . $disabled . "name=\"" . $prefix . "[h]\" id=\"" . $prefix . "_h\" class=\"form-control\">\n";

        $format = $ilUser->getTimeFormat();
        for ($i = 0; $i <= 23; $i++) {
            if ($format == ilCalendarSettings::TIME_FORMAT_24) {
                $sel_hour .= "<option value=\"$i\">" . sprintf("%02d", $i) . "</option>\n";
            } else {
                $sel_hour .= "<option value=\"$i\">" . date("ga", mktime($i, 0, 0)) . "</option>\n";
            }
        }
        $sel_hour .= "</select>\n";
        $sel_hour = preg_replace("/(value\=\"$hour\")/", "$1 selected=\"selected\"", $sel_hour);

        // build minutes select
        $sel_minute .= "<select " . $disabled . "name=\"" . $prefix . "[m]\" id=\"" . $prefix . "_m\" class=\"form-control\">\n";

        for ($i = 0; $i <= 59; $i = $i + $minute_steps) {
            $sel_minute .= "<option value=\"$i\">" . sprintf("%02d", $i) . "</option>\n";
        }
        $sel_minute .= "</select>\n";
        $sel_minute = preg_replace("/(value\=\"$minute\")/", "$1 selected=\"selected\"", $sel_minute);

        if (!$short) {
            // build seconds select
            $sel_second .= "<select " . $disabled . "name=\"" . $prefix . "[s]\" id=\"" . $prefix . "_s\" class=\"form-control\">\n";

            for ($i = 0; $i <= 59; $i++) {
                $sel_second .= "<option value=\"$i\">" . sprintf("%02d", $i) . "</option>\n";
            }
            $sel_second .= "</select>\n";
            $sel_second = preg_replace("/(value\=\"$second\")/", "$1 selected=\"selected\"", $sel_second);
        }
        $timeformat = $lng->text["lang_timeformat"];
        if (strlen($timeformat) == 0) {
            $timeformat = "H:i:s";
        }
        $timeformat = strtolower(preg_replace("/\W/", "", $timeformat));
        $timeformat = preg_replace("/(\w)/", "%%$1", $timeformat);
        $timeformat = preg_replace("/%%h/", $sel_hour, $timeformat);
        $timeformat = preg_replace("/%%i/", $sel_minute, $timeformat);
        if ($short) {
            $timeformat = preg_replace("/%%s/", "", $timeformat);
        } else {
            $timeformat = preg_replace("/%%s/", $sel_second, $timeformat);
        }
        return $timeformat;
    }

    public static function is_email($a_email, ilMailRfc822AddressParserFactory $mailAddressParserFactory = null)
    {
        global $DIC;

        $ilErr = $DIC["ilErr"];

        if ($mailAddressParserFactory === null) {
            $mailAddressParserFactory = new ilMailRfc822AddressParserFactory();
        }
        // additional check for ilias object is needed,
        // otherwise setup will fail with this if branch
        if (is_object($ilErr)) { // seems to work in Setup now
            try {
                $parser    = $mailAddressParserFactory->getParser($a_email);
                $addresses = $parser->parse();
                return count($addresses) == 1 && $addresses[0]->getHost() != ilMail::ILIAS_HOST;
            } catch (ilException $e) {
                return false;
            }
        } else {
            $tlds = strtolower(
                "AC|AD|AE|AERO|AF|AG|AI|AL|AM|AN|AO|AQ|AR|ARPA|AS|ASIA|AT|AU|AW|AX|AZ|BA|BB|BD|BE|BF|BG|BH|BI|BIZ|BJ|BM|BN|BO|BR|BS|BT|BV|BW|BY|" .
                "BZ|CA|CAT|CC|CD|CF|CG|CH|CI|CK|CL|CM|CN|CO|COM|COOP|CR|CU|CV|CX|CY|CZ|DE|DJ|DK|DM|DO|DZ|EC|EDU|EE|EG|" .
                "ER|ES|ET|EU|FI|FJ|FK|FM|FO|FR|GA|GB|GD|GE|GF|GG|GH|GI|GL|GM|GN|GOV|GP|GQ|GR|GS|GT|GU|GW|GY|HK|HM|HN|HR|HT|" .
                "HU|ID|IE|IL|IM|IN|INFO|INT|IO|IQ|IR|IS|IT|JE|JM|JO|JOBS|JP|KE|KG|KH|KI|KM|KN|KP|KR|KW|KY|KZ|LA|LB|LC|" .
                "LI|LK|LR|LS|LT|LU|LV|LY|MA|MC|MD|ME|MG|MH|MIL|MK|ML|MM|MN|MO|MOBI|MP|MQ|MR|MS|MT|MU|MUSEUM|MV|MW|MX|" .
                "MY|MZ|NA|NAME|NC|NE|NET|NF|NG|NI|NL|NO|NP|NR|NU|NZ|OM|ORG|PA|PE|PF|PG|PH|PK|PL|PM|PN|PR|PRO|PS|" .
                "PT|PW|PY|QA|RE|RO|RS|RU|RW|SA|SB|SC|SD|SE|SG|SH|SI|SJ|SK|SL|SM|SN|SO|SR|ST|SU|SV|SY|SZ|TC|TD|TEL|" .
                "TF|TG|TH|TJ|TK|TL|TM|TN|TO|TP|TR|TRAVEL|TT|TV|TW|TZ|UA|UG|UK|US|UY|UZ|VA|VC|VE|VG|VI|VN|VU|" .
                "WF|WS|XN|YE|YT|YU|ZA|ZM|ZW"
            );
            
            return(preg_match("/^[-_.[:alnum:]]+@((([[:alnum:]]|[[:alnum:]][[:alnum:]-]*[[:alnum:]])\.)+(" . $tlds . ")|(([0-9][0-9]?|[0-1][0-9][0-9]|[2][0-4][0-9]|[2][5][0-5])\.){3}([0-9][0-9]?|[0-1][0-9][0-9]|[2][0-4][0-9]|[2][5][0-5]))$/i", $a_email));
        }
    }

    public static function isPassword($a_passwd, &$customError = null)
    {
        global $DIC;

        $lng = $DIC->language();
        
        include_once('./Services/PrivacySecurity/classes/class.ilSecuritySettings.php');
        $security = ilSecuritySettings::_getInstance();

        // check if password is empty
        if (empty($a_passwd)) {
            $customError = $lng->txt('password_empty');
            return false;
        }
        
        $isPassword = true;
        $errors = array();
        
        // check if password to short
        if ($security->getPasswordMinLength() > 0 && strlen($a_passwd) < $security->getPasswordMinLength()) {
            $errors[] = sprintf($lng->txt('password_to_short'), $security->getPasswordMinLength());
            $isPassword = false;
        }
        
        // check if password not to long
        // Hmmmmm, maybe we should discuss this limitation. In my opinion it is stupid to limit the password length ;-). There should only be a technical limitation (field size in database).
        if ($security->getPasswordMaxLength() > 0 && strlen($a_passwd) > $security->getPasswordMaxLength()) {
            $errors[] = sprintf($lng->txt('password_to_long'), $security->getPasswordMaxLength());
            $isPassword = false;
        }

        // if password must contains Chars and Numbers
        if ($security->isPasswordCharsAndNumbersEnabled()) {
            $hasCharsAndNumbers = true;

            // check password for existing chars
            if (!preg_match('/[A-Za-z]+/', $a_passwd)) {
                $hasCharsAndNumbers = false;
            }

            // check password for existing numbers
            if (!preg_match('/[0-9]+/', $a_passwd)) {
                $hasCharsAndNumbers = false;
            }

            if (!$hasCharsAndNumbers) {
                $errors[] = $lng->txt('password_must_chars_and_numbers');
                $isPassword = false;
            }
        }

        require_once 'Services/Utilities/classes/class.ilStr.php';
        if ($security->getPasswordNumberOfUppercaseChars() > 0) {
            if (ilStr::strLen($a_passwd) - ilStr::strLen(preg_replace('/[A-Z]/', '', $a_passwd)) < $security->getPasswordNumberOfUppercaseChars()) {
                $errors[]   = sprintf($lng->txt('password_must_contain_ucase_chars'), $security->getPasswordNumberOfUppercaseChars());
                $isPassword = false;
            }
        }

        if ($security->getPasswordNumberOfLowercaseChars() > 0) {
            if (ilStr::strLen($a_passwd) - ilStr::strLen(preg_replace('/[a-z]/', '', $a_passwd)) < $security->getPasswordNumberOfLowercaseChars()) {
                $errors[]   = sprintf($lng->txt('password_must_contain_lcase_chars'), $security->getPasswordNumberOfLowercaseChars());
                $isPassword = false;
            }
        }

        // if password must contains Special-Chars
        if ($security->isPasswordSpecialCharsEnabled()) {
            // check password for existing special-chars
            if (!preg_match(self::getPasswordValidChars(true, true), $a_passwd)) {
                $errors[] = $lng->txt('password_must_special_chars');
                $isPassword = false;
            }
        }
        
        // ensure password matches the positive list of chars/special-chars
        if (!preg_match(self::getPasswordValidChars(), $a_passwd)) {
            $errors[] = $lng->txt('password_contains_invalid_chars');
            $isPassword = false;
        }
        
        // build custom error message
        if (count($errors) == 1) {
            $customError = $errors[0];
        } elseif (count($errors) > 1) {
            $customError = $lng->txt('password_multiple_errors');
            $customError .= '<br />' . implode('<br />', $errors);
        }

        return $isPassword;
    }

    public static function isPasswordValidForUserContext($clear_text_password, $user, &$error_language_variable = null)
    {
        include_once 'Services/PrivacySecurity/classes/class.ilSecuritySettings.php';
        $security = ilSecuritySettings::_getInstance();

        $login = null;

        if (is_string($user)) {
            $login = $user;
        } elseif (is_array($user)) {
            // Try to get loginname and user_id from array
            $login  = $user['login'];
            $userId = $user['id'];
        } elseif ($user instanceof ilObjUser) {
            $login  = $user->getLogin();
            $userId = $user->getId();
        }

        // The user context (user instance or id) can be used for further validation (e.g. compare a password with the users' password history, etc.) in future releases.

        if ($login && (int) $security->getPasswordMustNotContainLoginnameStatus() &&
            strpos(strtolower($clear_text_password), strtolower($login)) !== false
        ) {
            $error_language_variable = 'password_contains_parts_of_login_err';
            return false;
        }

        return true;
    }

    public static function getPasswordValidChars($a_as_regex = true, $a_only_special_chars = false)
    {
        if ($a_as_regex) {
            if ($a_only_special_chars) {
                return '/[_\.\+\?\#\-\*\@!\$\%\~\/\:\;]+/';
            } else {
                return '/^[A-Za-z0-9_\.\+\?\#\-\*\@!\$\%\~\/\:\;]+$/';
            }
        } else {
            return 'A-Z a-z 0-9 _.+?#-*@!$%~/:;';
        }
    }

    public static function getPasswordRequirementsInfo()
    {
        global $DIC;

        $lng = $DIC->language();

        include_once('./Services/PrivacySecurity/classes/class.ilSecuritySettings.php');
        $security = ilSecuritySettings::_getInstance();
        
        $infos = array(sprintf($lng->txt('password_allow_chars'), self::getPasswordValidChars(false)));
                
        // check if password to short
        if ($security->getPasswordMinLength() > 0) {
            $infos[] = sprintf($lng->txt('password_to_short'), $security->getPasswordMinLength());
        }
        
        // check if password not to long
        if ($security->getPasswordMaxLength() > 0) {
            $infos[] = sprintf($lng->txt('password_to_long'), $security->getPasswordMaxLength());
        }

        // if password must contains Chars and Numbers
        if ($security->isPasswordCharsAndNumbersEnabled()) {
            $infos[] = $lng->txt('password_must_chars_and_numbers');
        }

        // if password must contains Special-Chars
        if ($security->isPasswordSpecialCharsEnabled()) {
            $infos[] = $lng->txt('password_must_special_chars');
        }

        if ($security->getPasswordNumberOfUppercaseChars() > 0) {
            $infos[] = sprintf($lng->txt('password_must_contain_ucase_chars'), $security->getPasswordNumberOfUppercaseChars());
        }

        if ($security->getPasswordNumberOfLowercaseChars() > 0) {
            $infos[] = sprintf($lng->txt('password_must_contain_lcase_chars'), $security->getPasswordNumberOfLowercaseChars());
        }

        return implode('<br />', $infos);
    }

    /*
    * validates a login
    * @access   public
    * @param    string  login
    * @return   boolean true if valid
    */
    public static function isLogin($a_login)
    {
        if (empty($a_login)) {
            return false;
        }

        if (strlen($a_login) < 3) {
            return false;
        }

        // FIXME - If ILIAS is configured to use RFC 822
        //         compliant mail addresses we should not
        //         allow the @ character.
        if (!preg_match("/^[A-Za-z0-9_\.\+\*\@!\$\%\~\-]+$/", $a_login)) {
            return false;
        }

        return true;
    }

    public static function shortenText(
        $a_str,
        $a_len,
        $a_dots = false,
        $a_next_blank = false,
        $a_keep_extension = false
    ) {
        include_once("./Services/Utilities/classes/class.ilStr.php");
        if (ilStr::strLen($a_str) > $a_len) {
            if ($a_next_blank) {
                $len = ilStr::strPos($a_str, " ", $a_len);
            } else {
                $len = $a_len;
            }
            // BEGIN WebDAV
            //             - Shorten names in the middle, before the filename extension
            //             Workaround for Windows WebDAV Client:
            //             Use the unicode ellipsis symbol for shortening instead of
            //             three full stop characters.
            if ($a_keep_extension) {
                $p = strrpos($a_str, '.');      // this messes up normal shortening, see bug #6190
            }
            if ($p === false || $p == 0 || strlen($a_str) - $p > $a_len) {
                $a_str = ilStr::subStr($a_str, 0, $len);
                if ($a_dots) {
                    $a_str .= "\xe2\x80\xa6"; // UTF-8 encoding for Unicode ellipsis character.
                }
            } else {
                if ($a_dots) {
                    $a_str = ilStr::subStr($a_str, 0, $len - (strlen($a_str) - $p + 1)) . "\xe2\x80\xa6" . substr($a_str, $p);
                } else {
                    $a_str = ilStr::subStr($a_str, 0, $len - (strlen($a_str) - $p + 1)) . substr($a_str, $p);
                }
            }
        }

        return $a_str;
    }


    public static function shortenWords($a_str, $a_len = 30, $a_dots = true)
    {
        include_once("./Services/Utilities/classes/class.ilStr.php");
        $str_arr = explode(" ", $a_str);
        
        for ($i = 0; $i < count($str_arr); $i++) {
            if (ilStr::strLen($str_arr[$i]) > $a_len) {
                $str_arr[$i] = ilStr::subStr($str_arr[$i], 0, $a_len);
                if ($a_dots) {
                    $str_arr[$i].= "...";
                }
            }
        }
        
        return implode($str_arr, " ");
    }

    public static function attribsToArray($a_str)
    {
        $attribs = array();
        while (is_int(strpos($a_str, "="))) {
            $eq_pos = strpos($a_str, "=");
            $qu1_pos = strpos($a_str, "\"");
            $qu2_pos = strpos(substr($a_str, $qu1_pos + 1), "\"") + $qu1_pos + 1;
            if (is_int($eq_pos) && is_int($qu1_pos) && is_int($qu2_pos)) {
                $var = trim(substr($a_str, 0, $eq_pos));
                $val = trim(substr($a_str, $qu1_pos + 1, ($qu2_pos - $qu1_pos) - 1));
                $attribs[$var] = $val;
                $a_str = substr($a_str, $qu2_pos + 1);
            } else {
                $a_str = "";
            }
        }
        return $attribs;
    }


    public static function rCopy($a_sdir, $a_tdir, $preserveTimeAttributes = false)
    {
        $sourceFS = LegacyPathHelper::deriveFilesystemFrom($a_sdir);
        $targetFS = LegacyPathHelper::deriveFilesystemFrom($a_tdir);

        $sourceDir = LegacyPathHelper::createRelativePath($a_sdir);
        $targetDir = LegacyPathHelper::createRelativePath($a_tdir);

        // check if arguments are directories
        if (!$sourceFS->hasDir($sourceDir)) {
            return false;
        }

        $sourceList = $sourceFS->listContents($sourceDir, true);

        foreach ($sourceList as $item) {
            if ($item->isDir()) {
                continue;
            }
            try {
                $itemPath = $targetDir . '/' . substr($item->getPath(), strlen($sourceDir));
                $stream = $sourceFS->readStream($item->getPath());
                $targetFS->writeStream($itemPath, $stream);
            } catch (\ILIAS\Filesystem\Exception\FileAlreadyExistsException $e) {
                // Do nothing with that type of exception
            }
        }

        return true;
    }


    public static function getWebspaceDir($mode = "filesystem")
    {
        if ($mode == "filesystem") {
            return "./" . ILIAS_WEB_DIR . "/" . CLIENT_ID;
        } else {
            if (defined("ILIAS_MODULE")) {
                return "../" . ILIAS_WEB_DIR . "/" . CLIENT_ID;
            } else {
                return "./" . ILIAS_WEB_DIR . "/" . CLIENT_ID;
            }
        }
    }

    public static function getDataDir()
    {
        return CLIENT_DATA_DIR;
    }

    public static function getUsersOnline($a_user_id = 0)
    {
        include_once("./Services/User/classes/class.ilObjUser.php");
        return ilObjUser::_getUsersOnline($a_user_id);
    }

    public static function getAssociatedUsersOnline($a_user_id)
    {
        include_once("./Services/User/classes/class.ilObjUser.php");
        return ilObjUser::_getAssociatedUsersOnline($a_user_id);
    }

    public static function ilTempnam($a_temp_path = null)
    {
        if ($a_temp_path === null) {
            $temp_path = ilUtil::getDataDir() . "/temp";
        } else {
            $temp_path = $a_temp_path;
        }
        
        if (!is_dir($temp_path)) {
            ilUtil::createDirectory($temp_path);
        }
        $temp_name = tempnam($temp_path, "tmp");
        // --->
        // added the following line because tempnam creates a backslash on some
        // Windows systems which leads to problems, because the "...\tmp..." can be
        // interpreted as "...{TAB-CHARACTER}...". The normal slash works fine
        // even under windows (Helmut Schottmüller, 2005-08-31)
        $temp_name = str_replace("\\", "/", $temp_name);
        // --->
        unlink($temp_name);
        return $temp_name;
    }


    public static function createDirectory($a_dir, $a_mod = 0755)
    {
        ilUtil::makeDir($a_dir);
        //@mkdir($a_dir);
        //@chmod($a_dir, $a_mod);
    }


    public static function unzip($a_file, $overwrite = false, $a_flat = false)
    {
        global $DIC;

        $log = $DIC->logger()->root();

        if (!is_file($a_file)) {
            return;
        }
        
        // if flat, move file to temp directory first
        if ($a_flat) {
            $tmpdir = ilUtil::ilTempnam();
            ilUtil::makeDir($tmpdir);
            copy($a_file, $tmpdir . DIRECTORY_SEPARATOR . basename($a_file));
            $orig_file = $a_file;
            $a_file = $tmpdir . DIRECTORY_SEPARATOR . basename($a_file);
            $origpathinfo = pathinfo($orig_file);
        }
        
        $pathinfo = pathinfo($a_file);
        $dir = $pathinfo["dirname"];
        $file = $pathinfo["basename"];

        // unzip
        $cdir = getcwd();
        chdir($dir);
        $unzip = PATH_TO_UNZIP;

        // the following workaround has been removed due to bug
        // http://www.ilias.de/mantis/view.php?id=7578
        // since the workaround is quite old, it may not be necessary
        // anymore, alex 9 Oct 2012
        /*
                // workaround for unzip problem (unzip of subdirectories fails, so
                // we create the subdirectories ourselves first)
                // get list
                $unzipcmd = "-Z -1 ".ilUtil::escapeShellArg($file);
                $arr = ilUtil::execQuoted($unzip, $unzipcmd);
                $zdirs = array();

                foreach($arr as $line)
                {
                    if(is_int(strpos($line, "/")))
                    {
                        $zdir = substr($line, 0, strrpos($line, "/"));
                        $nr = substr_count($zdir, "/");
                        //echo $zdir." ".$nr."<br>";
                        while ($zdir != "")
                        {
                            $nr = substr_count($zdir, "/");
                            $zdirs[$zdir] = $nr;                                // collect directories
                            //echo $dir." ".$nr."<br>";
                            $zdir = substr($zdir, 0, strrpos($zdir, "/"));
                        }
                    }
                }

                asort($zdirs);

                foreach($zdirs as $zdir => $nr)                         // create directories
                {
                    ilUtil::createDirectory($zdir);
                }
        */

        // real unzip
        if (!$overwrite) {
            $unzipcmd = ilUtil::escapeShellArg($file);
        } else {
            $unzipcmd = "-o " . ilUtil::escapeShellArg($file);
        }
        ilUtil::execQuoted($unzip, $unzipcmd);

        chdir($cdir);

        // remove all sym links
        clearstatcache();                       // prevent is_link from using cache
        $dir_realpath = realpath($dir);
        foreach (new RecursiveIteratorIterator(new RecursiveDirectoryIterator($dir)) as $name => $f) {
            if (is_link($name)) {
                $target = readlink($name);
                if (substr($target, 0, strlen($dir_realpath)) != $dir_realpath) {
                    unlink($name);
                    $log->info("Removed symlink " . $name);
                }
            }
        }

        // if flat, get all files and move them to original directory
        if ($a_flat) {
            include_once("./Services/Utilities/classes/class.ilFileUtils.php");
            $filearray = array();
            ilFileUtils::recursive_dirscan($tmpdir, $filearray);
            if (is_array($filearray["file"])) {
                foreach ($filearray["file"] as $k => $f) {
                    if (substr($f, 0, 1) != "." && $f != basename($orig_file)) {
                        copy($filearray["path"][$k] . $f, $origpathinfo["dirname"] . DIRECTORY_SEPARATOR . $f);
                    }
                }
            }
            ilUtil::delDir($tmpdir);
        }
    }

    public static function zip($a_dir, $a_file, $compress_content = false)
    {
        $cdir = getcwd();

        if ($compress_content) {
            $a_dir .="/*";
            $pathinfo = pathinfo($a_dir);
            chdir($pathinfo["dirname"]);
        }
        
        $pathinfo = pathinfo($a_file);
        $dir = $pathinfo["dirname"];
        $file = $pathinfo["basename"];

        if (!$compress_content) {
            chdir($dir);
        }

        $zip = PATH_TO_ZIP;
        
        if (!$zip) {
            chdir($cdir);
            return false;
        }

        if (is_array($a_dir)) {
            $source = "";
            foreach ($a_dir as $dir) {
                $name = basename($dir);
                $source.= " " . ilUtil::escapeShellArg($name);
            }
        } else {
            $name = basename($a_dir);
            if (trim($name) != "*") {
                $source = ilUtil::escapeShellArg($name);
            } else {
                $source = $name;
            }
        }

        $zipcmd = "-r " . ilUtil::escapeShellArg($a_file) . " " . $source;
        ilUtil::execQuoted($zip, $zipcmd);
        chdir($cdir);
        return true;
    }

    public static function CreateIsoFromFolder($a_dir, $a_file)
    {
        $cdir = getcwd();

        $pathinfo = pathinfo($a_dir);
        chdir($pathinfo["dirname"]);
        
        $pathinfo = pathinfo($a_file);
        $dir = $pathinfo["dirname"];
        $file = $pathinfo["basename"];
        $zipcmd = "-r " . ilUtil::escapeShellArg($a_file) . " " . $source;

        $mkisofs = PATH_TO_MKISOFS;
        if (!$mkisofs) {
            chdir($cdir);
            return false;
        }
        
        $name = basename($a_dir);
        $source = ilUtil::escapeShellArg($name);

        $zipcmd = "-r -J -o " . $a_file . " " . $source;
        ilUtil::execQuoted($mkisofs, $zipcmd);
        chdir($cdir);
        return true;
    }
    
    public static function getConvertCmd()
    {
        return PATH_TO_CONVERT;
    }
    
    public static function execConvert($args)
    {
        ilUtil::execQuoted(PATH_TO_CONVERT, $args);
    }
    
    public static function isConvertVersionAtLeast($a_version)
    {
        $current_version = ilUtil::execQuoted(PATH_TO_CONVERT, "--version");
        $current_version = self::processConvertVersion($current_version[0]);
        $version = self::processConvertVersion($a_version);
        if ($current_version >= $version) {
            return true;
        }
        return false;
    }
    
    protected static function processConvertVersion($a_version)
    {
        if (preg_match("/([0-9]+)\.([0-9]+)\.([0-9]+)([\.|\-]([0-9]+))?/", $a_version, $match)) {
            $version = str_pad($match[1], 2, 0, STR_PAD_LEFT) .
                str_pad($match[2], 2, 0, STR_PAD_LEFT) .
                str_pad($match[3], 2, 0, STR_PAD_LEFT) .
                str_pad($match[5], 2, 0, STR_PAD_LEFT);
            return (int) $version;
        }
    }

    public static function convertImage(
        $a_from,
        $a_to,
        $a_target_format = "",
        $a_geometry = "",
        $a_background_color = ""
    ) {
        $format_str = ($a_target_format != "")
            ? strtoupper($a_target_format) . ":"
            : "";
        $geometry = "";
        if ($a_geometry != "") {
            if (is_int(strpos($a_geometry, "x"))) {
                $geometry = " -geometry " . $a_geometry . " ";
            } else {
                $geometry = " -geometry " . $a_geometry . "x" . $a_geometry . " ";
            }
        }
        
        $bg_color = ($a_background_color != "")
            ? " -background color " . $a_background_color . " "
            : "";
        $convert_cmd = ilUtil::escapeShellArg($a_from) . " " . $bg_color . $geometry . ilUtil::escapeShellArg($format_str . $a_to);

        ilUtil::execConvert($convert_cmd);
    }

    public static function resizeImage($a_from, $a_to, $a_width, $a_height, $a_constrain_prop = false)
    {
        if ($a_constrain_prop) {
            $size = " -geometry " . $a_width . "x" . $a_height . " ";
        } else {
            $size = " -resize " . $a_width . "x" . $a_height . "! ";
        }
        $convert_cmd = ilUtil::escapeShellArg($a_from) . " " . $size . ilUtil::escapeShellArg($a_to);

        ilUtil::execConvert($convert_cmd);
    }
    
    public static function img($a_src, $a_alt = "", $a_width = "", $a_height = "", $a_border = 0, $a_id = "", $a_class = "")
    {
        $img = '<img src="' . $a_src . '"';
        if ($a_alt != "") {
            $img.= ' alt="' . htmlspecialchars($a_alt) . '" title="' . htmlspecialchars($a_alt) . '"';
        }
        if ($a_width != "") {
            $img.= ' width="' . htmlspecialchars($a_width) . '"';
        }
        if ($a_height != "") {
            $img.= ' height="' . htmlspecialchars($a_height) . '"';
        }
        if ($a_class != "") {
            $img.= ' class="' . $a_class . '"';
        }
        if ($a_id != "") {
            $img.= ' id="' . $a_id . '"';
        }
        $img.= ' border="' . (int) $a_border . '"/>';

        return $img;
    }

    public static function deliverData($a_data, $a_filename, $mime = "application/octet-stream", $charset = "")
    {
        $disposition = "attachment"; // "inline" to view file in browser or "attachment" to download to hard disk
        //              $mime = "application/octet-stream"; // or whatever the mime type is

        include_once './Services/Http/classes/class.ilHTTPS.php';
        
        //if($_SERVER['HTTPS'])
        if (ilHTTPS::getInstance()->isDetected()) {

            // Added different handling for IE and HTTPS => send pragma after content informations
            #header("Pragma: ");
            #header("Cache-Control: ");
            #header("Expires: Mon, 26 Jul 1997 05:00:00 GMT");
            #header("Last-Modified: " . gmdate("D, d M Y H:i:s") . " GMT");
            #header("Cache-Control: no-store, no-cache, must-revalidate"); // HTTP/1.1
            #header("Cache-Control: post-check=0, pre-check=0", false);
        } elseif ($disposition == "attachment") {
            header("Cache-control: private");
        } else {
            header("Cache-Control: no-cache, must-revalidate");
            header("Pragma: no-cache");
        }

        $ascii_filename = ilUtil::getASCIIFilename($a_filename);

        if (strlen($charset)) {
            $charset = "; charset=$charset";
        }
        header("Content-Type: $mime$charset");
        header("Content-Disposition:$disposition; filename=\"" . $ascii_filename . "\"");
        header("Content-Description: " . $ascii_filename);
        header("Content-Length: " . (string) (strlen($a_data)));

        //if($_SERVER['HTTPS'])
        if (ilHTTPS::getInstance()->isDetected()) {
            header('Cache-Control: must-revalidate, post-check=0, pre-check=0');
            header('Pragma: public');
        }

        header("Connection: close");
        echo $a_data;
        exit;
    }

    // BEGIN WebDAV: Show file in browser or provide it as attachment
    public static function deliverFile(
        $a_file,
        $a_filename,
        $a_mime = '',
        $isInline = false,
        $removeAfterDelivery = false,
        $a_exit_after = true
    ) {
        global $DIC;
        // should we fail silently?
        if (!file_exists($a_file)) {
            return false;
        }
        $delivery = new ilFileDelivery($a_file);

        if ($isInline) {
            $delivery->setDisposition(ilFileDelivery::DISP_INLINE);
        } else {
            $delivery->setDisposition(ilFileDelivery::DISP_ATTACHMENT);
        }

        if (strlen($a_mime)) {
            $delivery->setMimeType($a_mime);
        }

        $delivery->setDownloadFileName($a_filename);
        $delivery->setConvertFileNameToAsci((bool) !$DIC['ilClientIniFile']->readVariable('file_access', 'disable_ascii'));
        $delivery->setDeleteFile($removeAfterDelivery);
        $delivery->deliver();
    }


    public static function readFile($a_file)
    {
        $chunksize = 1*(1024*1024); // how many bytes per chunk
        $buffer = '';
        $handle = fopen($a_file, 'rb');
        if ($handle === false) {
            return false;
        }
        while (!feof($handle)) {
            $buffer = fread($handle, $chunksize);
            print $buffer;
        }
        return fclose($handle);
    }

    public static function getASCIIFilename($a_filename)
    {
        // The filename must be converted to ASCII, as of RFC 2183,
        // section 2.3.


                
        // #15914 - try to fix german umlauts
        $umlauts = array("Ä"=>"Ae", "Ö"=>"Oe", "Ü"=>"Ue",
            "ä"=>"ae", "ö"=>"oe", "ü"=>"ue", "ß"=>"ss");
        foreach ($umlauts as $src => $tgt) {
            $a_filename = str_replace($src, $tgt, $a_filename);
        }
        
        $ascii_filename = htmlentities($a_filename, ENT_NOQUOTES, 'UTF-8');
        $ascii_filename = preg_replace('/\&(.)[^;]*;/', '\\1', $ascii_filename);
        $ascii_filename = preg_replace('/[\x7f-\xff]/', '_', $ascii_filename);
        
        // OS do not allow the following characters in filenames: \/:*?"<>|
        $ascii_filename = preg_replace('/[:\x5c\/\*\?\"<>\|]/', '_', $ascii_filename);
        return $ascii_filename;
    }

    public static function htmlentitiesOutsideHTMLTags($htmlText)
    {
        $matches = array();
        $sep = '###HTMLTAG###';

        preg_match_all("@<[^>]*>@", $htmlText, $matches);
        $tmp = preg_replace("@(<[^>]*>)@", $sep, $htmlText);
        $tmp = explode($sep, $tmp);

        for ($i=0; $i<count($tmp); $i++) {
            $tmp[$i] = htmlentities($tmp[$i], ENT_COMPAT, "UTF-8");
        }

        $tmp = join($sep, $tmp);

        for ($i=0; $i<count($matches[0]); $i++) {
            $tmp = preg_replace("@$sep@", $matches[0][$i], $tmp, 1);
        }

        return $tmp;
    }

    public static function getJavaPath()
    {
        return PATH_TO_JAVA;
        //global $ilias;

        //return $ilias->getSetting("java_path");
    }

    public static function appendUrlParameterString($a_url, $a_par, $xml_style = false)
    {
        $amp = $xml_style
            ? "&amp;"
            : "&";
        
        $url = (is_int(strpos($a_url, "?")))
            ? $a_url . $amp . $a_par
            : $a_url . "?" . $a_par;

        return $url;
    }

    public static function makeDir($a_dir)
    {
        $a_dir = trim($a_dir);

        // remove trailing slash (bugfix for php 4.2.x)
        if (substr($a_dir, -1) == "/") {
            $a_dir = substr($a_dir, 0, -1);
        }

        // check if a_dir comes with a path
        if (!($path = substr($a_dir, 0, strrpos($a_dir, "/") - strlen($a_dir)))) {
            $path = ".";
        }

        // create directory with file permissions of parent directory
        umask(0000);
        return @mkdir($a_dir, fileperms($path));
    }


    public static function makeDirParents($a_dir)
    {
        $dirs = array($a_dir);
        $a_dir = dirname($a_dir);
        $last_dirname = '';

        while ($last_dirname != $a_dir) {
            array_unshift($dirs, $a_dir);
            $last_dirname = $a_dir;
            $a_dir = dirname($a_dir);
        }

        // find the first existing dir
        $reverse_paths = array_reverse($dirs, true);
        $found_index = -1;
        foreach ($reverse_paths as $key => $value) {
            if ($found_index == -1) {
                if (is_dir($value)) {
                    $found_index = $key;
                }
            }
        }

        umask(0000);
        foreach ($dirs as $dirindex => $dir) {
            // starting with the longest existing path
            if ($dirindex >= $found_index) {
                if (!file_exists($dir)) {
                    if (strcmp(substr($dir, strlen($dir)-1, 1), "/") == 0) {
                        // on some systems there is an error when there is a slash
                        // at the end of a directory in mkdir, see Mantis #2554
                        $dir = substr($dir, 0, strlen($dir)-1);
                    }
                    if (!mkdir($dir, $umask)) {
                        error_log("Can't make directory: $dir");
                        return false;
                    }
                } elseif (!is_dir($dir)) {
                    error_log("$dir is not a directory");
                    return false;
                } else {
                    // get umask of the last existing parent directory
                    $umask = fileperms($dir);
                }
            }
        }
        return true;
    }


    public static function delDir($a_dir, $a_clean_only = false)
    {
        if (!is_dir($a_dir) || is_int(strpos($a_dir, ".."))) {
            return;
        }

        $current_dir = opendir($a_dir);

        $files = array();

        // this extra loop has been necessary because of a strange bug
        // at least on MacOS X. A looped readdir() didn't work
        // correctly with larger directories
        // when an unlink happened inside the loop. Getting all files
        // into the memory first solved the problem.
        while ($entryname = readdir($current_dir)) {
            $files[] = $entryname;
        }

        foreach ($files as $file) {
            if (is_dir($a_dir . "/" . $file) and ($file != "." and $file!="..")) {
                ilUtil::delDir($a_dir . "/" . $file);
            } elseif ($file != "." and $file != "..") {
                unlink($a_dir . "/" . $file);
            }
        }

        closedir($current_dir);
        if (!$a_clean_only) {
            @rmdir($a_dir);
        }
    }


    public static function getDir($a_dir, $a_rec = false, $a_sub_dir = "")
    {
        $current_dir = opendir($a_dir . $a_sub_dir);

        $dirs = array();
        $files = array();
        $subitems = array();
        while ($entry = readdir($current_dir)) {
            if (is_dir($a_dir . "/" . $entry)) {
                $dirs[$entry] = array("type" => "dir", "entry" => $entry,
                    "subdir" => $a_sub_dir);
                if ($a_rec && $entry != "." && $entry != "..") {
                    $si = ilUtil::getDir($a_dir, true, $a_sub_dir . "/" . $entry);
                    $subitems = array_merge($subitems, $si);
                }
            } else {
                if ($entry != "." && $entry != "..") {
                    $size = filesize($a_dir . $a_sub_dir . "/" . $entry);
                    $files[$entry] = array("type" => "file", "entry" => $entry,
                    "size" => $size, "subdir" => $a_sub_dir);
                }
            }
        }
        ksort($dirs);
        ksort($files);

        return array_merge($dirs, $files, $subitems);
    }

    public static function stripSlashesArray($a_arr, $a_strip_html = true, $a_allow = "")
    {
        if (is_array($a_arr)) {
            foreach ($a_arr as $k => $v) {
                $a_arr[$k] = ilUtil::stripSlashes($v, $a_strip_html, $a_allow);
            }
        }

        return $a_arr;
    }

    public static function getClientIdByString($clientId)
    {
        $df = new \ILIAS\Data\Factory;

        return $df->clientId($clientId);
    }
    
    public static function stripSlashesRecursive($a_data, $a_strip_html = true, $a_allow = "")
    {
        if (is_array($a_data)) {
            foreach ($a_data as $k => $v) {
                if (is_array($v)) {
                    $a_data[$k] = ilUtil::stripSlashesRecursive($v, $a_strip_html, $a_allow);
                } else {
                    $a_data[$k] = ilUtil::stripSlashes($v, $a_strip_html, $a_allow);
                }
            }
        } else {
            $a_data = ilUtil::stripSlashes($a_data, $a_strip_html, $a_allow);
        }

        return $a_data;
    }

    public static function stripSlashes($a_str, $a_strip_html = true, $a_allow = "")
    {
        if (ini_get("magic_quotes_gpc")) {
            $a_str = stripslashes($a_str);
        }
        //echo "<br><br>-".$a_strip_html."-".htmlentities($a_str);
        //echo "<br>-".htmlentities(ilUtil::secureString($a_str, $a_strip_html, $a_allow));
        return ilUtil::secureString($a_str, $a_strip_html, $a_allow);
    }
    
    public static function stripOnlySlashes($a_str)
    {
        if (ini_get("magic_quotes_gpc")) {
            $a_str = stripslashes($a_str);
        }

        return $a_str;
    }

    public static function secureString($a_str, $a_strip_html = true, $a_allow = "")
    {
        // check whether all allowed tags can be made secure
        $only_secure = true;
        $allow_tags = explode(">", $a_allow);
        $sec_tags = ilUtil::getSecureTags();
        $allow_array = array();
        foreach ($allow_tags as $allow) {
            if ($allow != "") {
                $allow = str_replace("<", "", $allow);

                if (!in_array($allow, $sec_tags)) {
                    $only_secure = false;
                }
                $allow_array[] = $allow;
            }
        }

        // default behaviour: allow only secure tags 1:1
        if (($only_secure || $a_allow == "") && $a_strip_html) {
            if ($a_allow == "") {
                $allow_array = array("b", "i", "strong", "em", "code", "cite",
                    "gap", "sub", "sup", "pre", "strike", "bdo");
            }

            // this currently removes parts of strings like "a <= b"
            // because "a <= b" is treated like "<spam onclick='hurt()'>ss</spam>"
            $a_str = ilUtil::maskSecureTags($a_str, $allow_array);
            $a_str = strip_tags($a_str);                // strip all other tags
            $a_str = ilUtil::unmaskSecureTags($a_str, $allow_array);

        // a possible solution could be something like:
            // $a_str = str_replace("<", "&lt;", $a_str);
            // $a_str = str_replace(">", "&gt;", $a_str);
            // $a_str = ilUtil::unmaskSecureTags($a_str, $allow_array);
            //
            // output would be ok then, but input fields would show
            // "a &lt;= b" for input "a <= b" if data is brought back to a form
        } else {
            // only for scripts, that need to allow more/other tags and parameters
            if ($a_strip_html) {
                $a_str = ilUtil::stripScriptHTML($a_str, $a_allow);
            }
        }

        return $a_str;
    }

    public static function getSecureTags()
    {
        return array("strong", "em", "u", "strike", "ol", "li", "ul", "p", "div",
            "i", "b", "code", "sup", "sub", "pre", "gap", "a", "img", "bdo");
    }

    public static function maskSecureTags($a_str, $allow_array)
    {
        foreach ($allow_array as $t) {
            switch ($t) {
                case "a":
                    $a_str = ilUtil::maskAttributeTag($a_str, "a", "href");
                    break;

                case "img":
                    $a_str = ilUtil::maskAttributeTag($a_str, "img", "src");
                    break;

                case "p":
                case "div":
                    $a_str = ilUtil::maskTag($a_str, $t, array(
                        array("param" => "align", "value" => "left"),
                        array("param" => "align", "value" => "center"),
                        array("param" => "align", "value" => "justify"),
                        array("param" => "align", "value" => "right")
                        ));
                    break;

                default:
                    $a_str = ilUtil::maskTag($a_str, $t);
                    break;
            }
        }

        return $a_str;
    }

    public static function unmaskSecureTags($a_str, $allow_array)
    {
        foreach ($allow_array as $t) {
            switch ($t) {
                case "a":
                    $a_str = ilUtil::unmaskAttributeTag($a_str, "a", "href");
                    break;

                case "img":
                    $a_str = ilUtil::unmaskAttributeTag($a_str, "img", "src");
                    break;

                case "p":
                case "div":
                    $a_str = ilUtil::unmaskTag($a_str, $t, array(
                        array("param" => "align", "value" => "left"),
                        array("param" => "align", "value" => "center"),
                        array("param" => "align", "value" => "justify"),
                        array("param" => "align", "value" => "right")
                        ));
                    break;

                default:
                    $a_str = ilUtil::unmaskTag($a_str, $t);
                    break;
            }
        }

        return $a_str;
    }

    public static function securePlainString($a_str)
    {
        if (ini_get("magic_quotes_gpc")) {
            return stripslashes($a_str);
        } else {
            return $a_str;
        }
    }
    public static function htmlencodePlainString($a_str, $a_make_links_clickable, $a_detect_goto_links = false)
    {
        $encoded = "";

        if ($a_make_links_clickable) {
            // Find text sequences in the plain text string which match
            // the URI syntax rules, and pass them to ilUtil::makeClickable.
            // Encode all other text sequences in the plain text string using
            // htmlspecialchars and nl2br.
            // The following expressions matches URI's as specified in RFC 2396.
            //
            // The expression matches URI's, which start with some well known
            // schemes, like "http:", or with "www.". This must be followed
            // by at least one of the following RFC 2396 expressions:
            // - alphanum:           [a-zA-Z0-9]
            // - reserved:           [;\/?:|&=+$,]
            // - mark:               [\\-_.!~*\'()]
            // - escaped:            %[0-9a-fA-F]{2}
            // - fragment delimiter: #
            // - uric_no_slash:      [;?:@&=+$,]
            $matches = array();
            $numberOfMatches = preg_match_all('/(?:(?:http|https|ftp|ftps|mailto):|www\.)(?:[a-zA-Z0-9]|[;\/?:|&=+$,]|[\\-_.!~*\'()]|%[0-9a-fA-F]{2}|#|[;?:@&=+$,])+/', $a_str, $matches, PREG_OFFSET_CAPTURE);
            $pos1 = 0;
            $encoded = "";

            foreach ($matches[0] as $match) {
                $matched_text = $match[0];
                $pos2 = $match[1];

                // encode plain text
                $encoded .= nl2br(htmlspecialchars(substr($a_str, $pos1, $pos2 - $pos1)));

                // encode URI
                $encoded .= ilUtil::makeClickable($matched_text, $a_detect_goto_links);


                $pos1 = $pos2 + strlen($matched_text);
            }
            if ($pos1 < strlen($a_str)) {
                $encoded .= nl2br(htmlspecialchars(substr($a_str, $pos1)));
            }
        } else {
            $encoded = nl2br(htmlspecialchars($a_str));
        }
        return $encoded;
    }


    public static function maskAttributeTag($a_str, $tag, $tag_att)
    {
        global $DIC;

        $ilLog = $DIC["ilLog"];

        $ws = "[\s]*";
        $att = $ws . "[^>]*" . $ws;

        while (preg_match(
            '/<(' . $tag . $att . '(' . $tag_att . $ws . '="' . $ws . '(([$@!*()~;,_0-9A-z\/:=%.&#?+\-])*)")' . $att . ')>/i',
            $a_str,
            $found
        )) {
            $old_str = $a_str;
            $a_str = preg_replace(
                "/<" . preg_quote($found[1], "/") . ">/i",
                '&lt;' . $tag . ' ' . $tag_att . $tag_att . '="' . $found[3] . '"&gt;',
                $a_str
            );
            if ($old_str == $a_str) {
                $ilLog->write("ilUtil::maskA-" . htmlentities($old_str) . " == " .
                    htmlentities($a_str));
                return $a_str;
            }
        }
        $a_str = str_ireplace(
            "</$tag>",
            "&lt;/$tag&gt;",
            $a_str
        );
        return $a_str;
    }

    public static function unmaskAttributeTag($a_str, $tag, $tag_att)
    {
        global $DIC;

        $ilLog = $DIC["ilLog"];

        while (preg_match(
            '/&lt;(' . $tag . ' ' . $tag_att . $tag_att . '="(([$@!*()~;,_0-9A-z\/:=%.&#?+\-])*)")&gt;/i',
            $a_str,
            $found
        )) {
            $old_str = $a_str;
            $a_str = preg_replace(
                "/&lt;" . preg_quote($found[1], "/") . "&gt;/i",
                '<' . $tag . ' ' . $tag_att . '="' . ilUtil::secureLink($found[2]) . '">',
                $a_str
            );
            if ($old_str == $a_str) {
                $ilLog->write("ilUtil::unmaskA-" . htmlentities($old_str) . " == " .
                    htmlentities($a_str));
                return $a_str;
            }
        }
        $a_str = str_replace('&lt;/' . $tag . '&gt;', '</' . $tag . '>', $a_str);
        return $a_str;
    }

    public static function maskTag($a_str, $t, $fix_param = "")
    {
        $a_str = str_replace(
            array("<$t>", "<" . strtoupper($t) . ">"),
            "&lt;" . $t . "&gt;",
            $a_str
        );
        $a_str = str_replace(
            array("</$t>", "</" . strtoupper($t) . ">"),
            "&lt;/" . $t . "&gt;",
            $a_str
        );

        if (is_array($fix_param)) {
            foreach ($fix_param  as $p) {
                $k = $p["param"];
                $v = $p["value"];
                $a_str = str_replace(
                    "<$t $k=\"$v\">",
                    "&lt;" . "$t $k=\"$v\"" . "&gt;",
                    $a_str
                );
            }
        }

        return $a_str;
    }

    public static function unmaskTag($a_str, $t, $fix_param = "")
    {
        $a_str = str_replace("&lt;" . $t . "&gt;", "<" . $t . ">", $a_str);
        $a_str = str_replace("&lt;/" . $t . "&gt;", "</" . $t . ">", $a_str);

        if (is_array($fix_param)) {
            foreach ($fix_param  as $p) {
                $k = $p["param"];
                $v = $p["value"];
                $a_str = str_replace(
                    "&lt;$t $k=\"$v\"&gt;",
                    "<" . "$t $k=\"$v\"" . ">",
                    $a_str
                );
            }
        }
        return $a_str;
    }

    public static function secureLink($a_str)
    {
        $a_str = str_ireplace("javascript", "jvscrpt", $a_str);
        $a_str = str_ireplace(array("%00", "%0a", "%0d", "%1a", "&#00;", "&#x00;",
            "&#0;", "&#x0;", "&#x0a;", "&#x0d;", "&#10;", "&#13;"), "-", $a_str);
        return $a_str;
    }

    public static function stripScriptHTML($a_str, $a_allow = "", $a_rm_js = true)
    {
        //$a_str = strip_tags($a_str, $a_allow);

        $negativestr = "a,abbr,acronym,address,applet,area,base,basefont," .
            "big,blockquote,body,br,button,caption,center,cite,code,col," .
            "colgroup,dd,del,dfn,dir,div,dl,dt,em,fieldset,font,form,frame," .
            "frameset,h1,h2,h3,h4,h5,h6,head,hr,html,i,iframe,img,input,ins,isindex,kbd," .
            "label,legend,li,link,map,menu,meta,noframes,noscript,object,ol," .
            "optgroup,option,p,param,q,s,samp,script,select,small,span," .
            "strike,strong,style,sub,sup,table,tbody,td,textarea,tfoot,th,thead," .
            "title,tr,tt,u,ul,var";
        $a_allow = strtolower($a_allow);
        $negatives = explode(",", $negativestr);
        $outer_old_str = "";
        while ($outer_old_str != $a_str) {
            $outer_old_str = $a_str;
            foreach ($negatives as $item) {
                $pos = strpos($a_allow, "<$item>");

                // remove complete tag, if not allowed
                if ($pos === false) {
                    $old_str = "";
                    while ($old_str != $a_str) {
                        $old_str = $a_str;
                        $a_str = preg_replace("/<\/?\s*$item(\/?)\s*>/i", "", $a_str);
                        $a_str = preg_replace("/<\/?\s*$item(\/?)\s+([^>]*)>/i", "", $a_str);
                    }
                }
            }
        }

        if ($a_rm_js) {
            // remove all attributes if an "on..." attribute is given
            $a_str = preg_replace("/<\s*\w*(\/?)(\s+[^>]*)?(\s+on[^>]*)>/i", "", $a_str);

            // remove all attributes if a "javascript" is within tag
            $a_str = preg_replace("/<\s*\w*(\/?)\s+[^>]*javascript[^>]*>/i", "", $a_str);

            // remove all attributes if an "expression" is within tag
            // (IE allows something like <b style='width:expression(alert(1))'>test</b>)
            $a_str = preg_replace("/<\s*\w*(\/?)\s+[^>]*expression[^>]*>/i", "", $a_str);
        }

        return $a_str;
    }

    public static function prepareFormOutput($a_str, $a_strip = false)
    {
        if ($a_strip) {
            $a_str = ilUtil::stripSlashes($a_str);
        }
        $a_str = htmlspecialchars($a_str);
        // Added replacement of curly brackets to prevent
        // problems with PEAR templates, because {xyz} will
        // be removed as unused template variable
        $a_str = str_replace("{", "&#123;", $a_str);
        $a_str = str_replace("}", "&#125;", $a_str);
        // needed for LaTeX conversion \\ in LaTeX is a line break
        // but without this replacement, php changes \\ to \
        $a_str = str_replace("\\", "&#92;", $a_str);
        return $a_str;
    }

    public static function secureUrl($url)
    {
        // check if url is valid (absolute or relative)
        if (filter_var($url, FILTER_VALIDATE_URL) === false &&
            filter_var("http://" . $url, FILTER_VALIDATE_URL) === false &&
            filter_var("http:" . $url, FILTER_VALIDATE_URL) === false &&
            filter_var("http://de.de" . $url, FILTER_VALIDATE_URL) === false &&
            filter_var("http://de.de/" . $url, FILTER_VALIDATE_URL) === false) {
            return "";
        }
        if (trim(strtolower(parse_url($url, PHP_URL_SCHEME))) == "javascript") {
            return "";
        }
        $url = htmlspecialchars($url, ENT_QUOTES);
        return $url;
    }



    public static function prepareDBString($a_str)
    {
        return addslashes($a_str);
    }


    public static function removeItemFromDesktops($a_id)
    {
        return ilObjUser::_removeItemFromDesktops($a_id);
    }


    public static function extractParameterString($a_parstr)
    {
        // parse parameters in array
        $par = array();
        $ok=true;
        while (($spos=strpos($a_parstr, "=")) && $ok) {
            // extract parameter
            $cpar = substr($a_parstr, 0, $spos);
            $a_parstr = substr($a_parstr, $spos, strlen($a_parstr)-$spos);
            while (substr($cpar, 0, 1)=="," ||substr($cpar, 0, 1)==" " || substr($cpar, 0, 1)==chr(13) || substr($cpar, 0, 1)==chr(10)) {
                $cpar = substr($cpar, 1, strlen($cpar)-1);
            }
            while (substr($cpar, strlen($cpar)-1, 1)==" " || substr($cpar, strlen($cpar)-1, 1)==chr(13) || substr($cpar, strlen($cpar)-1, 1)==chr(10)) {
                $cpar = substr($cpar, 0, strlen($cpar)-1);
            }

            // parameter name should only
            $cpar_old = "";
            while ($cpar != $cpar_old) {
                $cpar_old = $cpar;
                $cpar = preg_replace("/[^a-zA-Z0-9_]/i", "", $cpar);
            }

            // extract value
            if ($cpar != "") {
                if ($spos=strpos($a_parstr, "\"")) {
                    $a_parstr = substr($a_parstr, $spos+1, strlen($a_parstr)-$spos);
                    $spos=strpos($a_parstr, "\"");
                    if (is_int($spos)) {
                        $cval = substr($a_parstr, 0, $spos);
                        $par[$cpar]=$cval;
                        $a_parstr = substr($a_parstr, $spos+1, strlen($a_parstr)-$spos-1);
                    } else {
                        $ok=false;
                    }
                } else {
                    $ok=false;
                }
            }
        }

        if ($ok) {
            return $par;
        } else {
            return false;
        }
    }

    public static function assembleParameterString($a_par_arr)
    {
        if (is_array($a_par_arr)) {
            $target_arr = array();
            foreach ($a_par_arr as $par => $val) {
                $target_arr[] = "$par=\"$val\"";
            }
            $target_str = implode(", ", $target_arr);
        }

        return $target_str;
    }

    public static function dumpString($a_str)
    {
        $ret = $a_str . ": ";
        for ($i=0; $i<strlen($a_str); $i++) {
            $ret.= ord(substr($a_str, $i, 1)) . " ";
        }
        return $ret;
    }


    public static function yn2tf($a_yn)
    {
        if (strtolower($a_yn) == "y") {
            return true;
        } else {
            return false;
        }
    }

    public static function tf2yn($a_tf)
    {
        if ($a_tf) {
            return "y";
        } else {
            return "n";
        }
    }

    public static function sort_func($a, $b)
    {
        global $array_sortby,$array_sortorder;

        if (!isset($array_sortby)) {
            // occured in: setup -> new client -> install languages -> sorting of languages
            $array_sortby = 0;
        }
        
        // this comparison should give optimal results if
        // locale is provided and mb string functions are supported
        if ($array_sortorder == "asc") {
            return ilStr::strCmp($a[$array_sortby], $b[$array_sortby]);
        }

        if ($array_sortorder == "desc") {
            return !ilStr::strCmp($a[$array_sortby], $b[$array_sortby]);
            return strcoll(ilStr::strToUpper($b[$array_sortby]), ilStr::strToUpper($a[$array_sortby]));
        }
    }

    public static function sort_func_numeric($a, $b)
    {
        global $array_sortby,$array_sortorder;

        if ($array_sortorder == "asc") {
            return $a["$array_sortby"] > $b["$array_sortby"];
        }

        if ($array_sortorder == "desc") {
            return $a["$array_sortby"] < $b["$array_sortby"];
        }
    }
    public static function sortArray(
        $array,
        $a_array_sortby,
        $a_array_sortorder = 0,
        $a_numeric = false,
        $a_keep_keys = false
    ) {
        include_once("./Services/Utilities/classes/class.ilStr.php");
        
        // BEGIN WebDAV: Provide a 'stable' sort algorithm
        if (!$a_keep_keys) {
            return self::stableSortArray($array, $a_array_sortby, $a_array_sortorder, $a_numeric, $a_keep_keys);
        }
        // END WebDAV Provide a 'stable' sort algorithm

        global $array_sortby,$array_sortorder;
        $array_sortby = $a_array_sortby;

        if ($a_array_sortorder == "desc") {
            $array_sortorder = "desc";
        } else {
            $array_sortorder = "asc";
        }
        if ($a_numeric) {
            if ($a_keep_keys) {
                uasort($array, array("ilUtil", "sort_func_numeric"));
            } else {
                usort($array, array("ilUtil", "sort_func_numeric"));
            }
        } else {
            if ($a_keep_keys) {
                uasort($array, array("ilUtil", "sort_func"));
            } else {
                usort($array, array("ilUtil", "sort_func"));
            }
        }
        //usort($array,"ilUtil::sort_func");

        return $array;
    }
    // BEGIN WebDAV: Provide a 'stable' sort algorithm
    public static function stableSortArray($array, $a_array_sortby, $a_array_sortorder = 0, $a_numeric = false)
    {
        global $array_sortby,$array_sortorder;

        $array_sortby = $a_array_sortby;

        if ($a_array_sortorder == "desc") {
            $array_sortorder = "desc";
        } else {
            $array_sortorder = "asc";
        }

        // Create a copy of the array values for sorting
        $sort_array = array_values($array);

        if ($a_numeric) {
            ilUtil::mergesort($sort_array, array("ilUtil", "sort_func_numeric"));
        } else {
            ilUtil::mergesort($sort_array, array("ilUtil", "sort_func"));
        }

        return $sort_array;
    }
    public static function mergesort(&$array, $cmp_function = 'strcmp')
    {
        // Arrays of size < 2 require no action.
        if (count($array) < 2) {
            return;
        }

        // Split the array in half
        $halfway = count($array) / 2;
        $array1 = array_slice($array, 0, $halfway);
        $array2 = array_slice($array, $halfway);

        // Recurse to sort the two halves
        ilUtil::mergesort($array1, $cmp_function);
        ilUtil::mergesort($array2, $cmp_function);

        // If all of $array1 is <= all of $array2, just append them.
        if (call_user_func($cmp_function, end($array1), $array2[0]) < 1) {
            $array = array_merge($array1, $array2);
            return;
        }

        // Merge the two sorted arrays into a single sorted array
        $array = array();
        $ptr1 = $ptr2 = 0;
        while ($ptr1 < count($array1) && $ptr2 < count($array2)) {
            if (call_user_func($cmp_function, $array1[$ptr1], $array2[$ptr2]) < 1) {
                $array[] = $array1[$ptr1++];
            } else {
                $array[] = $array2[$ptr2++];
            }
        }

        // Merge the remainder
        while ($ptr1 < count($array1)) {
            $array[] = $array1[$ptr1++];
        }
        while ($ptr2 < count($array2)) {
            $array[] = $array2[$ptr2++];
        }

        return;
    }
    // END WebDAV: Provide a 'stable' sort algorithm

    public static function unique_multi_array($array, $sub_key)
    {
        $target = array();
        $existing_sub_key_values = array();

        foreach ($array as $key=>$sub_array) {
            if (!in_array($sub_array[$sub_key], $existing_sub_key_values)) {
                $existing_sub_key_values[] = $sub_array[$sub_key];
                $target[$key] = $sub_array;
            }
        }

        return $target;
    }


    public static function getGDSupportedImageType($a_desired_type)
    {
        $a_desired_type = strtolower($a_desired_type);
        // get supported Image Types
        $im_types = ImageTypes();

        switch ($a_desired_type) {
            case "jpg":
            case "jpeg":
            if ($im_types & IMG_JPG) {
                return "jpg";
            }
            if ($im_types & IMG_GIF) {
                return "gif";
            }
            if ($im_types & IMG_PNG) {
                return "png";
            }
            break;

            case "gif":
            if ($im_types & IMG_GIF) {
                return "gif";
            }
            if ($im_types & IMG_JPG) {
                return "jpg";
            }
            if ($im_types & IMG_PNG) {
                return "png";
            }
            break;

            case "png":
            if ($im_types & IMG_PNG) {
                return "png";
            }
            if ($im_types & IMG_JPG) {
                return "jpg";
            }
            if ($im_types & IMG_GIF) {
                return "gif";
            }
            break;

            case "svg":
            if ($im_types & IMG_PNG) {
                return "png";
            }
            if ($im_types & IMG_JPG) {
                return "jpg";
            }
            if ($im_types & IMG_GIF) {
                return "gif";
            }
            break;
        }

        return "";
    }

    public static function deducibleSize($a_mime)
    {
        if (($a_mime == "image/gif") || ($a_mime == "image/jpeg") ||
        ($a_mime == "image/png") || ($a_mime == "application/x-shockwave-flash") ||
        ($a_mime == "image/tiff") || ($a_mime == "image/x-ms-bmp") ||
        ($a_mime == "image/psd") || ($a_mime == "image/iff")) {
            return true;
        } else {
            return false;
        }
    }


    public static function redirect($a_script)
    {
        global $DIC;

        if (!isset($DIC['ilCtrl']) || !$DIC['ilCtrl'] instanceof ilCtrl) {
            $ctrl = new ilCtrl();
        } else {
            $ctrl = $DIC->ctrl();
        }
        $ctrl->redirectToURL($a_script);
    }

    public static function insertInstIntoID($a_value)
    {
        if (substr($a_value, 0, 4) == "il__") {
            $a_value = "il_" . IL_INST_ID . "_" . substr($a_value, 4, strlen($a_value) - 4);
        }

        return $a_value;
    }

    public static function groupNameExists($a_group_name, $a_id = 0)
    {
        global $DIC;

        $ilDB = $DIC->database();

        $ilErr = null;
        if (isset($DIC["ilErr"])) {
            $ilErr = $DIC["ilErr"];
        }

        if (empty($a_group_name)) {
            $message = __METHOD__ . ": No groupname given!";
            $ilErr->raiseError($message, $ilErr->WARNING);
        }

        $clause = ($a_id) ? " AND obj_id != " . $ilDB->quote($a_id) . " " : "";

        $q = "SELECT obj_id FROM object_data " .
        "WHERE title = " . $ilDB->quote($a_group_name, "text") . " " .
        "AND type = " . $ilDB->quote("grp", "text") .
        $clause;

        $r = $ilDB->query($q);

        if ($r->numRows()) {
            return true;
        } else {
            return false;
        }
    }

    public static function getMemString()
    {
        $my_pid = getmypid();
        return ("MEMORY USAGE (% KB PID ): " . `ps -eo%mem,rss,pid | grep $my_pid`);
    }

    public static function isWindows()
    {
        if (strtolower(substr(php_uname(), 0, 3)) == "win") {
            return true;
        }
        return false;
    }


    public static function escapeShellArg($a_arg)
    {
        setlocale(LC_CTYPE, "UTF8", "en_US.UTF-8"); // fix for PHP escapeshellcmd bug. See: http://bugs.php.net/bug.php?id=45132
        // see also ilias bug 5630
        return escapeshellarg($a_arg);
    }

    public static function escapeShellCmd($a_arg)
    {
        if (ini_get('safe_mode') == 1) {
            return $a_arg;
        }
        setlocale(LC_CTYPE, "UTF8", "en_US.UTF-8"); // fix for PHP escapeshellcmd bug. See: http://bugs.php.net/bug.php?id=45132
        return escapeshellcmd($a_arg);
    }
    
    public static function execQuoted($cmd, $args = null)
    {
        global $DIC;
        
        if (ilUtil::isWindows() && strpos($cmd, " ") !== false && substr($cmd, 0, 1) !== '"') {
            // cmd won't work without quotes
            $cmd = '"' . $cmd . '"';
            if ($args) {
                // args are also quoted, workaround is to quote the whole command AGAIN
                // was fixed in php 5.2 (see php bug #25361)
                if (version_compare(phpversion(), "5.2", "<") && strpos($args, '"') !== false) {
                    $cmd = '"' . $cmd . " " . $args . '"';
                }
                // args are not quoted or php is fixed, just append
                else {
                    $cmd .= " " . $args;
                }
            }
        }
        // nothing todo, just append args
        elseif ($args) {
            $cmd .= " " . $args;
        }

        exec($cmd, $arr);

        $DIC->logger()->root()->debug("ilUtil::execQuoted: " . $cmd . ".");

        return $arr;
    }

    public static function excelTime($year = "", $month = "", $day = "", $hour = "", $minute = "", $second = "")
    {
        $starting_time = mktime(0, 0, 0, 1, 2, 1970);
        if (strcmp("$year$month$day$hour$minute$second", "") == 0) {
            $target_time = time();
        } else {
            if ($year < 1970) {
                return 0;
            }
        }
        $target_time = mktime($hour, $minute, $second, $month, $day, $year);
        $difference = $target_time - $starting_time;
        $days = (($difference - ($difference % 86400)) / 86400);
        $difference = $difference - ($days * 86400) + 3600;
        
        // #15343 - using a global locale leads to , instead of . for (implicit) floats
        return str_replace(",", ".", ($days + 25570 + ($difference / 86400)));
    }

    public static function renameExecutables($a_dir)
    {
        $def_arr = explode(",", SUFFIX_REPL_DEFAULT);
        foreach ($def_arr as $def) {
            ilUtil::rRenameSuffix($a_dir, trim($def), "sec");
        }

        $def_arr = explode(",", SUFFIX_REPL_ADDITIONAL);
        foreach ($def_arr as $def) {
            ilUtil::rRenameSuffix($a_dir, trim($def), "sec");
        }
    }

    public static function getSafeFilename($a_initial_filename)
    {
        $file_peaces = explode('.', $a_initial_filename);

        $file_extension = array_pop($file_peaces);

        if (SUFFIX_REPL_ADDITIONAL) {
            $string_extensions = SUFFIX_REPL_DEFAULT . "," . SUFFIX_REPL_ADDITIONAL;
        } else {
            $string_extensions = SUFFIX_REPL_DEFAULT;
        }

        $sufixes = explode(",", $string_extensions);

        if (in_array($file_extension, $sufixes)) {
            $file_extension = "sec";
        }

        array_push($file_peaces, $file_extension);

        $safe_filename = "";
        foreach ($file_peaces as $piece) {
            $safe_filename .= "$piece";
            if ($piece != end($file_peaces)) {
                $safe_filename .= ".";
            }
        }

        return $safe_filename;
    }

    public static function rRenameSuffix($a_dir, $a_old_suffix, $a_new_suffix)
    {
        if ($a_dir == "/" || $a_dir == "" || is_int(strpos($a_dir, ".."))
            || trim($a_old_suffix) == "") {
            return false;
        }

        // check if argument is directory
        if (!@is_dir($a_dir)) {
            return false;
        }

        // read a_dir
        $dir = opendir($a_dir);

        while ($file = readdir($dir)) {
            if ($file != "." and
            $file != "..") {
                // directories
                if (@is_dir($a_dir . "/" . $file)) {
                    ilUtil::rRenameSuffix($a_dir . "/" . $file, $a_old_suffix, $a_new_suffix);
                }

                // files
                if (@is_file($a_dir . "/" . $file)) {
                    // first check for files with trailing dot
                    if (strrpos($file, '.') == (strlen($file) - 1)) {
                        rename($a_dir . '/' . $file, substr($a_dir . '/' . $file, 0, -1));
                        $file = substr($file, 0, -1);
                    }

                    $path_info = pathinfo($a_dir . "/" . $file);

                    if (strtolower($path_info["extension"]) ==
                    strtolower($a_old_suffix)) {
                        $pos = strrpos($a_dir . "/" . $file, ".");
                        $new_name = substr($a_dir . "/" . $file, 0, $pos) . "." . $a_new_suffix;
                        rename($a_dir . "/" . $file, $new_name);
                    }
                }
            }
        }
        return true;
    }

    public static function isAPICall()
    {
        return  strpos($_SERVER["SCRIPT_FILENAME"], "api") !== false ||
        strpos($_SERVER["SCRIPT_FILENAME"], "dummy") !== false;
    }

    public static function KT_replaceParam($qstring, $paramName, $paramValue)
    {
        if (preg_match("/&" . $paramName . "=/", $qstring)) {
            return preg_replace("/&" . $paramName . "=[^&]+/", "&" . $paramName . "=" . urlencode($paramValue), $qstring);
        } else {
            return $qstring . "&" . $paramName . "=" . urlencode($paramValue);
        }
    }

    public static function replaceUrlParameterString($url, $parametersArray)
    {
        foreach ($parametersArray as $paramName => $paramValue) {
            $url = ilUtil::KT_replaceParam($url, $paramName, $paramValue);
        }
        return $url;
    }

    public static function generatePasswords($a_number)
    {
        $ret = array();
        srand((double) microtime()*1000000);
        
        include_once('./Services/PrivacySecurity/classes/class.ilSecuritySettings.php');
        $security = ilSecuritySettings::_getInstance();

        for ($i=1; $i<=$a_number; $i++) {
            $min = ($security->getPasswordMinLength() > 0)
                ? $security->getPasswordMinLength()
                : 6;
            $max = ($security->getPasswordMaxLength() > 0)
                ? $security->getPasswordMaxLength()
                : 10;
            if ($min > $max) {
                $max = $max + 1;
            }
            $random = new \ilRandom();
            $length  = $random->int($min, $max);
            $next  = $random->int(1, 2);
            $vowels = "aeiou";
            $vowels_uc = strtoupper($vowels);
            $consonants = "bcdfghjklmnpqrstvwxyz";
            $consonants_uc = strtoupper($consonants);
            $numbers = "1234567890";
            $special = "_.+?#-*@!$%~";
            $pw = "";
            
            if ($security->getPasswordNumberOfUppercaseChars() > 0) {
                for ($j = 0; $j < $security->getPasswordNumberOfUppercaseChars(); $j++) {
                    switch ($next) {
                        case 1:
                            $pw.= $consonants_uc[$random->int(0, strlen($consonants_uc) - 1)];
                            $next = 2;
                            break;
                        
                        case 2:
                            $pw.= $vowels_uc[$random->int(0, strlen($vowels_uc) - 1)];
                            $next = 1;
                            break;
                    }
                }
            }

            if ($security->isPasswordCharsAndNumbersEnabled()) {
                $pw.= $numbers[$random->int(0, strlen($numbers) - 1)];
            }

            if ($security->isPasswordSpecialCharsEnabled()) {
                $pw.= $special[$random->int(0, strlen($special) - 1)];
            }

            $num_lcase_chars = max($security->getPasswordNumberOfLowercaseChars(), $length - strlen($pw));
            for ($j = 0; $j < $num_lcase_chars; $j++) {
                switch ($next) {
                    case 1:
                        $pw.= $consonants[$random->int(0, strlen($consonants) - 1)];
                        $next = 2;
                        break;
                    
                    case 2:
                        $pw.= $vowels[$random->int(0, strlen($vowels) - 1)];
                        $next = 1;
                        break;
                }
            }

            $pw = str_shuffle($pw);
        
            $ret[] = $pw;
        }
        return $ret;
    }

    public static function removeTrailingPathSeparators($path)
    {
        $path = preg_replace("/[\/\\\]+$/", "", $path);
        return $path;
    }

    public static function array_php2js($data)
    {
        if (empty($data)) {
            $data = array();
        }

        foreach ($data as $k=>$datum) {
            if (is_null($datum)) {
                $data[$k] = 'null';
            }
            if (is_string($datum)) {
                $data[$k] = "'" . $datum . "'";
            }
            if (is_array($datum)) {
                $data[$k] = array_php2js($datum);
            }
        }

        return "[" . implode(', ', $data) . "]";
    }

    public static function virusHandling($a_file, $a_orig_name = "", $a_clean = true)
    {
        global $DIC;

        $lng = $DIC->language();

        if (IL_VIRUS_SCANNER != "None") {
            require_once("./Services/VirusScanner/classes/class.ilVirusScannerFactory.php");
            $vs = ilVirusScannerFactory::_getInstance();
            if (($vs_txt = $vs->scanFile($a_file, $a_orig_name)) != "") {
                if ($a_clean && (IL_VIRUS_CLEAN_COMMAND != "")) {
                    $clean_txt = $vs->cleanFile($a_file, $a_orig_name);
                    if ($vs->fileCleaned()) {
                        $vs_txt.= "<br />" . $lng->txt("cleaned_file") .
                            "<br />" . $clean_txt;
                        $vs_txt.= "<br />" . $lng->txt("repeat_scan");
                        if (($vs2_txt = $vs->scanFile($a_file, $a_orig_name)) != "") {
                            return array(false, nl2br($vs_txt) . "<br />" . $lng->txt("repeat_scan_failed") .
                                "<br />" . nl2br($vs2_txt));
                        } else {
                            return array(true, nl2br($vs_txt) . "<br />" . $lng->txt("repeat_scan_succeded"));
                        }
                    } else {
                        return array(false, nl2br($vs_txt) . "<br />" . $lng->txt("cleaning_failed"));
                    }
                } else {
                    return array(false, nl2br($vs_txt));
                }
            }
        }

        return array(true,"");
    }


    public static function moveUploadedFile($a_file, $a_name, $a_target, $a_raise_errors = true, $a_mode = "move_uploaded")
    {
        global $DIC;
        $targetFilename = basename($a_target);

        include_once("./Services/Utilities/classes/class.ilFileUtils.php");
        $targetFilename = ilFileUtils::getValidFilename($targetFilename);

        // Make sure the target is in a valid subfolder. (e.g. no uploads to ilias/setup/....)
        list($targetFilesystem, $targetDir) = self::sanitateTargetPath($a_target);

        $upload = $DIC->upload();

        // If the upload has not yet been processed make sure he gets processed now.
        if (!$upload->hasBeenProcessed()) {
            $upload->process();
        }

        try {
            if (!$upload->hasUploads()) {
                throw new ilException($DIC->language()->txt("upload_error_file_not_found"));
            }
            $UploadResult = $upload->getResults()[$a_file];
            $ProcessingStatus = $UploadResult->getStatus();
            if ($ProcessingStatus->getCode() === ProcessingStatus::REJECTED) {
                throw new ilException($ProcessingStatus->getMessage());
            }
        } catch (ilException $e) {
            if ($a_raise_errors) {
                throw $e;
            } else {
                ilUtil::sendFailure($e->getMessage(), true);
            }

            return false;
        }

        $upload->moveOneFileTo($UploadResult, $targetDir, $targetFilesystem, $targetFilename, true);

        return true;
    }


    public static function date_mysql2time($mysql_date_time)
    {
        list($datum, $uhrzeit) = explode(" ", $mysql_date_time);
        list($jahr, $monat, $tag) = explode("-", $datum);
        list($std, $min, $sec) = explode(":", $uhrzeit);
        return mktime((int) $std, (int) $min, (int) $sec, (int) $monat, (int) $tag, (int) $jahr);
    }
     
    public static function now()
    {
        return date("Y-m-d H:i:s");
    }

    public static function &processCSVRow(&$row, $quoteAll = false, $separator = ";", $outUTF8 = false, $compatibleWithMSExcel = true)
    {
        $resultarray = array();
        foreach ($row as $rowindex => $entry) {
            $surround = false;
            if ($quoteAll) {
                $surround = true;
            }
            if (strpos($entry, "\"") !== false) {
                $entry = str_replace("\"", "\"\"", $entry);
                $surround = true;
            }
            if (strpos($entry, $separator) !== false) {
                $surround = true;
            }
            if ($compatibleWithMSExcel) {
                // replace all CR LF with LF (for Excel for Windows compatibility
                $entry = str_replace(chr(13) . chr(10), chr(10), $entry);
            }
            if ($surround) {
                if ($outUTF8) {
                    $resultarray[$rowindex] = "\"" . $entry . "\"";
                } else {
                    $resultarray[$rowindex] = utf8_decode("\"" . $entry . "\"");
                }
            } else {
                if ($outUTF8) {
                    $resultarray[$rowindex] = $entry;
                } else {
                    $resultarray[$rowindex] = utf8_decode($entry);
                }
            }
        }
        return $resultarray;
    }

    // validates a domain name (example: www.ilias.de)
    public static function isDN($a_str)
    {
        return(preg_match("/^[a-z]+([a-z0-9-]*[a-z0-9]+)?(\.([a-z]+([a-z0-9-]*[a-z0-9]+)?)+)*$/", $a_str));
    }

    // validates an IP address (example: 192.168.1.1)
    public static function isIPv4($a_str)
    {
        return(preg_match("/^(\d{1,2}|1\d\d|2[0-4]\d|25[0-5])\.(\d{1,2}|1\d\d|2[0-4]\d|25[0-5])\." .
                          "(\d{1,2}|1\d\d|2[0-4]\d|25[0-5])\.(\d{1,2}|1\d\d|2[0-4]\d|25[0-5])$/", $a_str));
    }


    public static function _getObjectsByOperations($a_obj_type, $a_operation, $a_usr_id = 0, $limit = 0)
    {
        global $DIC;

        $ilDB = $DIC->database();
        $rbacreview = $DIC->rbac()->review();
        $ilAccess = $DIC->access();
        $ilUser = $DIC->user();
        $ilSetting = $DIC->settings();
        $tree = $DIC->repositoryTree();

        if (!is_array($a_obj_type)) {
            $where = "WHERE type = " . $ilDB->quote($a_obj_type, "text") . " ";
        } else {
            $where = "WHERE " . $ilDB->in("type", $a_obj_type, false, "text") . " ";
        }

        // limit number of results default is search result limit
        if (!$limit) {
            $limit = $ilSetting->get('search_max_hits', 100);
        }
        if ($limit == -1) {
            $limit = 10000;
        }

        // default to logged in usr
        $a_usr_id = $a_usr_id ? $a_usr_id : $ilUser->getId();
        $a_roles = $rbacreview->assignedRoles($a_usr_id);

        // Since no rbac_pa entries are available for the system role. This function returns !all! ref_ids in the case the user
        // is assigned to the system role
        if ($rbacreview->isAssigned($a_usr_id, SYSTEM_ROLE_ID)) {
            $query = "SELECT ref_id FROM object_reference obr LEFT JOIN object_data obd ON obr.obj_id = obd.obj_id " .
                "LEFT JOIN tree ON obr.ref_id = tree.child " .
                $where .
                "AND tree = 1";

            $res = $ilDB->query($query);
            $counter = 0;
            while ($row = $ilDB->fetchObject($res)) {
                // Filter recovery folder
                if ($tree->isGrandChild(RECOVERY_FOLDER_ID, $row->ref_id)) {
                    continue;
                }

                if ($counter++ >= $limit) {
                    break;
                }

                $ref_ids[] = $row->ref_id;
            }
            return $ref_ids ? $ref_ids : array();
        } // End Administrators

        // Check ownership if it is not asked for edit_permission or a create permission
        if ($a_operation == 'edit_permissions' or strpos($a_operation, 'create') !== false) {
            $check_owner = ") ";
        } else {
            $check_owner = "OR owner = " . $ilDB->quote($a_usr_id, "integer") . ") ";
        }

        $ops_ids = ilRbacReview::_getOperationIdsByName(array($a_operation));
        $ops_id = $ops_ids[0];

        $and = "AND ((" . $ilDB->in("rol_id", $a_roles, false, "integer") . " ";

        $query = "SELECT DISTINCT(obr.ref_id),obr.obj_id,type FROM object_reference obr " .
            "JOIN object_data obd ON obd.obj_id = obr.obj_id " .
            "LEFT JOIN rbac_pa  ON obr.ref_id = rbac_pa.ref_id " .
            $where .
            $and .
            "AND (" . $ilDB->like("ops_id", "text", "%i:" . $ops_id . "%") . " " .
            "OR " . $ilDB->like("ops_id", "text", "%:\"" . $ops_id . "\";%") . ")) " .
            $check_owner;

        $res = $ilDB->query($query);
        $counter = 0;
        while ($row = $res->fetchRow(ilDBConstants::FETCHMODE_OBJECT)) {
            if ($counter >= $limit) {
                break;
            }
            
            // Filter objects in recovery folder
            if ($tree->isGrandChild(RECOVERY_FOLDER_ID, $row->ref_id)) {
                continue;
            }
            
            // Check deleted, hierarchical access ...
            if ($ilAccess->checkAccessOfUser($a_usr_id, $a_operation, '', $row->ref_id, $row->type, $row->obj_id)) {
                $counter++;
                $ref_ids[] = $row->ref_id;
            }
        }
        return $ref_ids ? $ref_ids : array();
    }


    protected static function sanitateTargetPath($a_target)
    {
        switch (true) {
            case strpos($a_target, ILIAS_WEB_DIR . '/' . CLIENT_ID) === 0:
            case strpos($a_target, './' . ILIAS_WEB_DIR . '/' . CLIENT_ID) === 0:
            case strpos($a_target, CLIENT_WEB_DIR) === 0:
                $targetFilesystem = \ILIAS\FileUpload\Location::WEB;
                break;
            case strpos($a_target, CLIENT_DATA_DIR . "/temp") === 0:
                $targetFilesystem = \ILIAS\FileUpload\Location::TEMPORARY;
                break;
            case strpos($a_target, CLIENT_DATA_DIR) === 0:
                $targetFilesystem = \ILIAS\FileUpload\Location::STORAGE;
                break;
            case strpos($a_target, ILIAS_ABSOLUTE_PATH . '/Customizing') === 0:
                $targetFilesystem = \ILIAS\FileUpload\Location::CUSTOMIZING;
                break;
            default:
                throw new InvalidArgumentException("Can not move files to \"$a_target\" because path can not be mapped to web, storage or customizing location.");
        }

        $absTargetDir = dirname($a_target);
        $targetDir = LegacyPathHelper::createRelativePath($absTargetDir);

        return array( $targetFilesystem, $targetDir );
    }


    public function includeMathjax($a_tpl = null)
    {
        include_once './Services/MathJax/classes/class.ilMathJax.php';
        ilMathJax::getInstance()->includeMathJax($a_tpl);
    }

    public static function insertLatexImages($a_text, $a_start = '[tex]', $a_end = '[/tex]')
    {
        include_once './Services/MathJax/classes/class.ilMathJax.php';
        return ilMathJax::getInstance()->insertLatexImages($a_text, $a_start, $a_end);
    }

    public static function buildLatexImages($a_text, $a_dir)
    {
        include_once './Services/MathJax/classes/class.ilMathJax.php';
        return ilMathJax::getInstance()->insertLatexImages($a_text, '[tex]', '[/tex]', $a_dir . '/teximg', './teximg');
    }

    public static function prepareTextareaOutput($txt_output, $prepare_for_latex_output = false, $omitNl2BrWhenTextArea = false)
    {
        $result = $txt_output;
        $is_html = self::isHTML($result);

        if ($prepare_for_latex_output) {
            include_once './Services/MathJax/classes/class.ilMathJax.php';
            $result = ilMathJax::getInstance()->insertLatexImages($result, "<span class\=\"latex\">", "<\/span>");
            $result = ilMathJax::getInstance()->insertLatexImages($result, "\[tex\]", "\[\/tex\]");
        }

        // removed: did not work with magic_quotes_gpc = On
        if (!$is_html) {
            if (!$omitNl2BrWhenTextArea) {
                // if the string does not contain HTML code, replace the newlines with HTML line breaks
                $result = preg_replace("/[\n]/", "<br />", $result);
            }
        } else {
            // patch for problems with the <pre> tags in tinyMCE
            if (preg_match_all("/(<pre>.*?<\/pre>)/ims", $result, $matches)) {
                foreach ($matches[0] as $found) {
                    $replacement = "";
                    if (strpos("\n", $found) === false) {
                        $replacement = "\n";
                    }
                    $removed = preg_replace("/<br\s*?\/>/ims", $replacement, $found);
                    $result = str_replace($found, $removed, $result);
                }
            }
        }
        if ($prepare_for_latex_output) {
            // replace special characters to prevent problems with the ILIAS template system
            // eg. if someone uses {1} as an answer, nothing will be shown without the replacement
            $result = str_replace("{", "&#123;", $result);
            $result = str_replace("}", "&#125;", $result);
            $result = str_replace("\\", "&#92;", $result);
        }
        
        return $result;
    }

    public static function isHTML($a_text)
    {
        if (strlen(strip_tags($a_text)) < strlen($a_text)) {
            return true;
        }

        return false;
    }

    public static function period2String(ilDateTime $a_from, $a_to = null)
    {
        global $DIC;

        $lng = $DIC->language();
        
        if (!$a_to) {
            $a_to = new ilDateTime(time(), IL_CAL_UNIX);
        }
        
        $from = new DateTime($a_from->get(IL_CAL_DATETIME));
        $to = new DateTime($a_to->get(IL_CAL_DATETIME));
        $diff = $to->diff($from);
        
        $periods = array();
        $periods["years"] = $diff->format("%y");
        $periods["months"] = $diff->format("%m");
        $periods["days"] = $diff->format("%d");
        $periods["hours"] = $diff->format("%h");
        $periods["minutes"] = $diff->format("%i");
        $periods["seconds"] = $diff->format("%s");

        if (!array_sum($periods)) {
            return;
        }

        foreach ($periods as $key => $value) {
            if ($value) {
                $segment_name = ($value > 1)
                    ? $key
                    : substr($key, 0, -1);
                $array[] = $value . ' ' . $lng->txt($segment_name);
            }
        }
        
        $len = sizeof($array);
        if ($len > 3) {
            $array = array_slice($array, 0, (3-$len));
        }

        return implode(', ', $array);
    }

    public static function getFileSizeInfo()
    {
        $max_filesize = self::formatBytes(
            self::getUploadSizeLimitBytes()
        );
        
        global $DIC;

        $lng = $DIC->language();
        /*
        // get the value for the maximal uploadable filesize from the php.ini (if available)
        $umf=get_cfg_var("upload_max_filesize");
        // get the value for the maximal post data from the php.ini (if available)
        $pms=get_cfg_var("post_max_size");

        // use the smaller one as limit
        $max_filesize=min($umf, $pms);
        if (!$max_filesize) $max_filesize=max($umf, $pms);
        */
        return $lng->txt("file_notice") . " $max_filesize.";
    }

    public static function formatBytes($size, $decimals = 0)
    {
        $unit = array('', 'K', 'M', 'G', 'T', 'P');

        for ($i = 0, $maxUnits = count($unit); $size >= 1024 && $i <= $maxUnits; $i++) {
            $size /= 1024;
        }

        return round($size, $decimals) . $unit[$i];
    }
    
    public static function getUploadSizeLimitBytes()
    {
        $uploadSizeLimitBytes = min(
            self::convertPhpIniSizeValueToBytes(ini_get('post_max_size')),
            self::convertPhpIniSizeValueToBytes(ini_get('upload_max_filesize'))
        );
        
        return $uploadSizeLimitBytes;
    }
    
    public static function convertPhpIniSizeValueToBytes($phpIniSizeValue)
    {
        if (is_numeric($phpIniSizeValue)) {
            return $phpIniSizeValue;
        }

        $suffix = substr($phpIniSizeValue, -1);
        $value = substr($phpIniSizeValue, 0, -1);
        
        switch (strtoupper($suffix)) {
            case 'P':
                $value *= 1024;
                // no break
            case 'T':
                $value *= 1024;
                // no break
            case 'G':
                $value *= 1024;
                // no break
            case 'M':
                $value *= 1024;
                // no break
            case 'K':
                $value *= 1024;
                break;
        }
        
        return $value;
    }

    public static function __extractRefId($role_title)
    {
        $test_str = explode('_', $role_title);

        if ($test_str[0] == 'il') {
            $test2 = (int) $test_str[3];
            return is_numeric($test2) ? (int) $test2 : false;
        }
        return false;
    }

    public static function __extractId($ilias_id, $inst_id)
    {
        $test_str = explode('_', $ilias_id);

        if ($test_str[0] == 'il' && $test_str[1] == $inst_id && count($test_str) == 4) {
            $test2 = (int) $test_str[3];
            return is_numeric($test2) ? (int) $test2 : false;
        }
        return false;
    }

    public static function _sortIds($a_ids, $a_table, $a_field, $a_id_name)
    {
        global $DIC;

        $ilDB = $DIC->database();

        if (!$a_ids) {
            return array();
        }

        // use database to sort user array
        $where = "WHERE " . $a_id_name . " IN (";
        $where .= implode(",", ilUtil::quoteArray($a_ids));
        $where .= ") ";

        $query = "SELECT " . $a_id_name . " FROM " . $a_table . " " .
            $where .
            "ORDER BY " . $a_field;

        $res = $ilDB->query($query);
        while ($row = $res->fetchRow(ilDBConstants::FETCHMODE_OBJECT)) {
            $ids[] = $row->$a_id_name;
        }
        return $ids ? $ids : array();
    }

    public static function getMySQLTimestamp($a_ts)
    {
        global $DIC;

        $ilDB = $DIC->database();

        return $a_ts;
    }

    public static function quoteArray($a_array)
    {
        global $DIC;

        $ilDB = $DIC->database();


        if (!is_array($a_array) or !count($a_array)) {
            return array("''");
        }

        foreach ($a_array as $k => $item) {
            $a_array[$k] = $ilDB->quote($item);
        }

        return $a_array;
    }

    public static function sendInfo($a_info = "", $a_keep = false)
    {
        global $DIC;

        $tpl = $DIC["tpl"];
        $tpl->setMessage("info", $a_info, $a_keep);
    }

    public static function sendFailure($a_info = "", $a_keep = false)
    {
        global $DIC;

        if (isset($DIC["tpl"])) {
            $tpl = $DIC["tpl"];
            $tpl->setMessage("failure", $a_info, $a_keep);
        }
    }

    public static function sendQuestion($a_info = "", $a_keep = false)
    {
        global $DIC;

        $tpl = $DIC["tpl"];
        $tpl->setMessage("question", $a_info, $a_keep);
    }

    public static function sendSuccess($a_info = "", $a_keep = false)
    {
        global $DIC;

        $tpl = $DIC["tpl"];
        $tpl->setMessage("success", $a_info, $a_keep);
    }

    public static function infoPanel($a_keep = true)
    {
        global $DIC;

        $tpl = $DIC["tpl"];
        $lng = $DIC->language();
        $ilUser = $DIC->user();

        if (!empty($_SESSION["infopanel"]) and is_array($_SESSION["infopanel"])) {
            $tpl->addBlockFile(
                "INFOPANEL",
                "infopanel",
                "tpl.infopanel.html",
                "Services/Utilities"
            );
            $tpl->setCurrentBlock("infopanel");

            if (!empty($_SESSION["infopanel"]["text"])) {
                $link = "<a href=\"" . $_SESSION["infopanel"]["link"] . "\" target=\"" .
                    ilFrameTargetInfo::_getFrame("MainContent") .
                    "\">";
                $link .= $lng->txt($_SESSION["infopanel"]["text"]);
                $link .= "</a>";
            }

            // deactivated
            if (!empty($_SESSION["infopanel"]["img"])) {
                $link .= "<td><a href=\"" . $_SESSION["infopanel"]["link"] . "\" target=\"" .
                    ilFrameTargetInfo::_getFrame("MainContent") .
                    "\">";
                $link .= "<img src=\"" . "./templates/" . $ilUser->prefs["skin"] . "/images/" .
                    $_SESSION["infopanel"]["img"] . "\" border=\"0\" vspace=\"0\"/>";
                $link .= "</a></td>";
            }

            $tpl->setVariable("INFO_ICONS", $link);
            $tpl->parseCurrentBlock();
        }

        //if (!$a_keep)
        //{
        ilSession::clear("infopanel");
        //}
    }


    public static function dirsize($directory)
    {
        $size = 0;
        if (!is_dir($directory)) {
            // BEGIN DiskQuota Suppress PHP warning when attempting to determine
            //       dirsize of non-existing directory
            $size = @filesize($directory);
            // END DiskQuota Suppress PHP warning.
            return ($size === false) ? -1 : $size;
        }
        if ($DIR = opendir($directory)) {
            while (($dirfile = readdir($DIR)) !== false) {
                if (is_link($directory . DIRECTORY_SEPARATOR . $dirfile) || $dirfile == '.' || $dirfile == '..') {
                    continue;
                }
                if (is_file($directory . DIRECTORY_SEPARATOR . $dirfile)) {
                    $size += filesize($directory . DIRECTORY_SEPARATOR . $dirfile);
                } elseif (is_dir($directory . DIRECTORY_SEPARATOR . $dirfile)) {
                    // BEGIN DiskQuota: dirsize is not a global function anymore
                    $dirSize = ilUtil::dirsize($directory . DIRECTORY_SEPARATOR . $dirfile);
                    // END DiskQuota: dirsize is not a global function anymore
                    if ($dirSize >= 0) {
                        $size += $dirSize;
                    } else {
                        return -1;
                    }
                }
            }
            closedir($DIR);
        }
        return $size;
    }

    public static function randomhash()
    {
        $random = new \ilRandom();
        return md5($random->int(1, 9999999) + str_replace(" ", "", (string) microtime()));
    }
    
    public static function setCookie($a_cookie_name, $a_cookie_value = '', $a_also_set_super_global = true, $a_set_cookie_invalid = false)
    {
        /*
        if(!(bool)$a_set_cookie_invalid) $expire = IL_COOKIE_EXPIRE;
        else $expire = time() - (365*24*60*60);
        */
        // Temporary fix for feed.php
        if (!(bool) $a_set_cookie_invalid) {
            $expire = 0;
        } else {
            $expire = time() - (365*24*60*60);
        }
        /* We MUST NOT set the global constant here, because this affects the session_set_cookie_params() call as well
        if(!defined('IL_COOKIE_SECURE'))
        {
            define('IL_COOKIE_SECURE', false);
        }
        */
        $secure = false;
        if (defined('IL_COOKIE_SECURE')) {
            $secure = IL_COOKIE_SECURE;
        }

        setcookie(
            $a_cookie_name,
            $a_cookie_value,
            $expire,
            IL_COOKIE_PATH,
            IL_COOKIE_DOMAIN,
            $secure,
            IL_COOKIE_HTTPONLY
        );
                    
        if ((bool) $a_also_set_super_global) {
            $_COOKIE[$a_cookie_name] = $a_cookie_value;
        }
    }
    
    public static function _sanitizeFilemame($a_filename)
    {
        return strip_tags(self::stripSlashes($a_filename));
    }
    
    public static function _getHttpPath()
    {
        global $DIC;

        $ilIliasIniFile = $DIC["ilIliasIniFile"];
        
        if ($_SERVER['SHELL'] || php_sapi_name() == 'cli' ||
            // fallback for windows systems, useful in crons
            (class_exists("ilContext") && !ilContext::usesHTTP())) {
            return $ilIliasIniFile->readVariable('server', 'http_path');
        } else {
            return ILIAS_HTTP_PATH;
        }
    }
    
    public static function printBacktrace($a_limit = 0)
    {
        $bt = debug_backtrace();
        $cnt = 0;
        foreach ($bt as $t) {
            if ($cnt != 0 && ($a_limit == 0 || $cnt <= $a_limit)) {
                echo "<br>" . $t["file"] . ", " . $t["function"] . " [" . $t["line"] . "]";
            }
            $cnt++;
        }
        echo "<br>";
    }

    public static function parseImportId($a_import_id)
    {
        $exploded = explode('_', $a_import_id);

        $parsed['orig'] = $a_import_id;
        if ($exploded[0] == 'il') {
            $parsed['prefix'] = $exploded[0];
        }
        if (is_numeric($exploded[1])) {
            $parsed['inst_id'] = (int) $exploded[1];
        }
        $parsed['type'] = $exploded[2];

        if (is_numeric($exploded[3])) {
            $parsed['id'] = (int) $exploded[3];
        }
        return $parsed;
    }

    public static function unserializeSession($data)
    {
        $vars = preg_split(
            '/([a-zA-Z_\x7f-\xff][a-zA-Z0-9_\x7f-\xff^|]*)\|/',
            $data,
            -1,
            PREG_SPLIT_NO_EMPTY | PREG_SPLIT_DELIM_CAPTURE
        );

        $result = array();

        for ($i = 0; $vars[$i]; $i++) {
            $result[$vars[$i++]] = unserialize($vars[$i]);
        }

        return $result;
    }


    public function rangeDownload($file)
    {
        $fp = @fopen($file, 'rb');

        $size   = filesize($file); // File size
        $length = $size;           // Content length
        $start  = 0;               // Start byte
        $end    = $size - 1;       // End byte
        // Now that we've gotten so far without errors we send the accept range header
        /* At the moment we only support single ranges.
         * Multiple ranges requires some more work to ensure it works correctly
         * and comply with the spesifications: http://www.w3.org/Protocols/rfc2616/rfc2616-sec19.html#sec19.2
         *
         * Multirange support annouces itself with:
         * header('Accept-Ranges: bytes');
         *
         * Multirange content must be sent with multipart/byteranges mediatype,
         * (mediatype = mimetype)
         * as well as a boundry header to indicate the various chunks of data.
         */
        header("Accept-Ranges: 0-$length");
        // header('Accept-Ranges: bytes');
        // multipart/byteranges
        // http://www.w3.org/Protocols/rfc2616/rfc2616-sec19.html#sec19.2
        if (isset($_SERVER['HTTP_RANGE'])) {
            $c_start = $start;
            $c_end   = $end;
            // Extract the range string
            list(, $range) = explode('=', $_SERVER['HTTP_RANGE'], 2);
            // Make sure the client hasn't sent us a multibyte range
            if (strpos($range, ',') !== false) {

                // (?) Shoud this be issued here, or should the first
                // range be used? Or should the header be ignored and
                // we output the whole content?
                header('HTTP/1.1 416 Requested Range Not Satisfiable');
                header("Content-Range: bytes $start-$end/$size");
                // (?) Echo some info to the client?
                exit;
            }
            // If the range starts with an '-' we start from the beginning
            // If not, we forward the file pointer
            // And make sure to get the end byte if spesified
            if ($range == '-') {

                // The n-number of the last bytes is requested
                $c_start = $size - substr($range, 1);
            } else {
                $range  = explode('-', $range);
                $c_start = $range[0];
                $c_end   = (isset($range[1]) && is_numeric($range[1])) ? $range[1] : $size;
            }
            /* Check the range and make sure it's treated according to the specs.
             * http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html
             */
            // End bytes can not be larger than $end.
            $c_end = ($c_end > $end) ? $end : $c_end;
            // Validate the requested range and return an error if it's not correct.
            if ($c_start > $c_end || $c_start > $size - 1 || $c_end >= $size) {
                header('HTTP/1.1 416 Requested Range Not Satisfiable');
                header("Content-Range: bytes $start-$end/$size");
                // (?) Echo some info to the client?
                exit;
            }
            $start  = $c_start;
            $end    = $c_end;
            $length = $end - $start + 1; // Calculate new content length
            fseek($fp, $start);
            header('HTTP/1.1 206 Partial Content');
        }
        // Notify the client the byte range we'll be outputting
        header("Content-Range: bytes $start-$end/$size");
        header("Content-Length: $length");

        // Start buffered download
        $buffer = 1024 * 8;
        while (!feof($fp) && ($p = ftell($fp)) <= $end) {
            if ($p + $buffer > $end) {

                // In case we're only outputtin a chunk, make sure we don't
                // read past the length
                $buffer = $end - $p + 1;
            }
            set_time_limit(0); // Reset time limit for big files
            echo fread($fp, $buffer);
            flush(); // Free up memory. Otherwise large files will trigger PHP's memory limit.
        }

        fclose($fp);
    }
    
    
    //
    //  used to be in ilFormat
    //
    
    protected static function _getSizeMagnitude()
    {
        return 1024;
    }
    
    protected static function fmtFloat($a_float, $a_decimals=0, $a_dec_point = null, $a_thousands_sep = null, $a_suppress_dot_zero=false)
    {
        global $DIC;

        $lng = $DIC->language();

        if ($a_dec_point == null) {
            {
                $a_dec_point = ".";
            }
        }
        if ($a_dec_point == '-lang_sep_decimal-') {
            $a_dec_point = ".";
        }

        if ($a_thousands_sep == null) {
            $a_thousands_sep = $lng->txt('lang_sep_thousand');
        }
        if ($a_thousands_sep == '-lang_sep_thousand-') {
            $a_thousands_sep = ",";
        }

        $txt = number_format($a_float, $a_decimals, $a_dec_point, $a_thousands_sep);

        // remove trailing ".0"
        if (($a_suppress_dot_zero == 0 || $a_decimals == 0)
            && substr($txt, -2) == $a_dec_point . '0'
        ) {
            $txt = substr($txt, 0, strlen($txt) - 2);
        }
        if ($a_float == 0 and $txt == "") {
            $txt = "0";
        }

        return $txt;
    }
    
    public static function formatSize($size, $a_mode = 'short', $a_lng = null)
    {
        global $DIC;

        $lng = $DIC->language();
        if ($a_lng == null) {
            $a_lng = $lng;
        }

        $mag = self::_getSizeMagnitude();

        if ($size >= $mag * $mag * $mag) {
            $scaled_size = $size / $mag / $mag / $mag;
            $scaled_unit = 'lang_size_gb';
        } else {
            if ($size >= $mag * $mag) {
                $scaled_size = $size / $mag / $mag;
                $scaled_unit = 'lang_size_mb';
            } else {
                if ($size >= $mag) {
                    $scaled_size = $size / $mag;
                    $scaled_unit = 'lang_size_kb';
                } else {
                    $scaled_size = $size;
                    $scaled_unit = 'lang_size_bytes';
                }
            }
        }

        $result = self::fmtFloat($scaled_size, ($scaled_unit
                                                == 'lang_size_bytes') ? 0 : 1, $a_lng->txt('lang_sep_decimal'), $a_lng->txt('lang_sep_thousand'), true)
                  . ' ' . $a_lng->txt($scaled_unit);
        if ($a_mode == 'long' && $size > $mag) {
            $result .= ' (' . self::fmtFloat($size, 0, $a_lng->txt('lang_sep_decimal'), $a_lng->txt('lang_sep_thousand')) . ' '
                       . $a_lng->txt('lang_size_bytes') . ')';
        }

        return $result;
    }
    
    
    //
    // used for disk quotas
    //
    
    public static function MB2Bytes($a_value)
    {
        return  ((int) $a_value) * pow(self::_getSizeMagnitude(), 2);
    }
    
    public static function Bytes2MB($a_value)
    {
        return  ((int) $a_value) / (pow(self::_getSizeMagnitude(), 2));
    }

    public static function dbSupportsDisctinctUmlauts()
    {
        global $DIC;

        if (!isset(self::$db_supports_distinct_umlauts)) {
            $ilDB = $DIC->database();
            $set = $ilDB->query("SELECT (" . $ilDB->quote("A", "text") . " = " . $ilDB->quote("Ä", "text") . ") t FROM DUAL ");
            $rec = $ilDB->fetchAssoc($set);
            self::$db_supports_distinct_umlauts = !(bool) $rec["t"];
        }

        return self::$db_supports_distinct_umlauts;
    }

    public static function dumpVar($mixed = null)
    {
        echo '<pre>';
        var_dump($mixed);
        echo '</pre>';
    }
} // END class.ilUtil