<?php
/***********************************************
* File      :   wbxmlencoder.php
* Project   :   Z-Push
* Descr     :   WBXMLEncoder encodes to Wap Binary XML
*
* Created   :   01.10.2007
*
* Copyright 2007 - 2011 Zarafa Deutschland GmbH
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License, version 3,
* as published by the Free Software Foundation with the following additional
* term according to sec. 7:
*
* According to sec. 7 of the GNU Affero General Public License, version 3,
* the terms of the AGPL are supplemented with the following terms:
*
* "Zarafa" is a registered trademark of Zarafa B.V.
* "Z-Push" is a registered trademark of Zarafa Deutschland GmbH
* The licensing of the Program under the AGPL does not imply a trademark license.
* Therefore any rights, title and interest in our trademarks remain entirely with us.
*
* However, if you propagate an unmodified version of the Program you are
* allowed to use the term "Z-Push" to indicate that you distribute the Program.
* Furthermore you may use our trademarks where it is necessary to indicate
* the intended purpose of a product or service provided you use it in accordance
* with honest practices in industrial or commercial matters.
* If you want to propagate modified versions of the Program under the name "Z-Push",
* you may only do so if you have a written permission by Zarafa Deutschland GmbH
* (to acquire a permission please contact Zarafa at trademark@zarafa.com).
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program.  If not, see <http://www.gnu.org/licenses/>.
*
* Consult LICENSE file for details
************************************************/


class WBXMLEncoder extends WBXMLDefs {
    private $_dtd;
    private $_out;

    private $_tagcp;
    private $_attrcp;

    private $logStack = array();

    // We use a delayed output mechanism in which we only output a tag when it actually has something
    // in it. This can cause entire XML trees to disappear if they don't have output data in them; Ie
    // calling 'startTag' 10 times, and then 'endTag' will cause 0 bytes of output apart from the header.

    // Only when content() is called do we output the current stack of tags

    private $_stack;

    public function WBXMLEncoder($output) {
        // make sure WBXML_DEBUG is defined. It should be at this point
        if (!defined('WBXML_DEBUG')) define('WBXML_DEBUG', false);

        $this->_out = $output;

        $this->_tagcp = 0;
        $this->_attrcp = 0;

        // reverse-map the DTD
        foreach($this->dtd["namespaces"] as $nsid => $nsname) {
            $this->_dtd["namespaces"][$nsname] = $nsid;
        }

        foreach($this->dtd["codes"] as $cp => $value) {
            $this->_dtd["codes"][$cp] = array();
            foreach($this->dtd["codes"][$cp] as $tagid => $tagname) {
                $this->_dtd["codes"][$cp][$tagname] = $tagid;
            }
        }
        $this->_stack = array();
    }

    /**
     * Puts the WBXML header on the stream
     *
     * @access public
     * @return
     */
    public function startWBXML() {
        header("Content-Type: application/vnd.ms-sync.wbxml");

        $this->outByte(0x03); // WBXML 1.3
        $this->outMBUInt(0x01); // Public ID 1
        $this->outMBUInt(106); // UTF-8
        $this->outMBUInt(0x00); // string table length (0)
    }

    /**
     * Puts a StartTag on the output stack
     *
     * @param $tag
     * @param $attributes
     * @param $nocontent
     *
     * @access public
     * @return
     */
    public function startTag($tag, $attributes = false, $nocontent = false) {
        $stackelem = array();

        if(!$nocontent) {
            $stackelem['tag'] = $tag;
            $stackelem['attributes'] = $attributes;
            $stackelem['nocontent'] = $nocontent;
            $stackelem['sent'] = false;

            array_push($this->_stack, $stackelem);

            // If 'nocontent' is specified, then apparently the user wants to force
            // output of an empty tag, and we therefore output the stack here
        } else {
            $this->_outputStack();
            $this->_startTag($tag, $attributes, $nocontent);
        }
    }

    /**
     * Puts an EndTag on the stack
     *
     * @access public
     * @return
     */
    public function endTag() {
        $stackelem = array_pop($this->_stack);

        // Only output end tags for items that have had a start tag sent
        if($stackelem['sent']) {
            $this->_endTag();
        }
    }

    /**
     * Puts content on the output stack
     *
     * @param $content
     *
     * @access public
     * @return string
     */
    public function content($content) {
        // We need to filter out any \0 chars because it's the string terminator in WBXML. We currently
        // cannot send \0 characters within the XML content anywhere.
        $content = str_replace("\0","",$content);

        if("x" . $content == "x")
            return;
        $this->_outputStack();
        $this->_content($content);
    }

    /**----------------------------------------------------------------------------------------------------------
     * Private WBXMLEncoder stuff
     */

    /**
     * Output any tags on the stack that haven't been output yet
     *
     * @access private
     * @return
     */
    private function _outputStack() {
        for($i=0;$i<count($this->_stack);$i++) {
            if(!$this->_stack[$i]['sent']) {
                $this->_startTag($this->_stack[$i]['tag'], $this->_stack[$i]['attributes'], $this->_stack[$i]['nocontent']);
                $this->_stack[$i]['sent'] = true;
            }
        }
    }

    /**
     * Outputs an actual start tag
     *
     * @access private
     * @return
     */
    private function _startTag($tag, $attributes = false, $nocontent = false) {
        $this->logStartTag($tag, $attributes, $nocontent);

        $mapping = $this->getMapping($tag);

        if(!$mapping)
            return false;

        if($this->_tagcp != $mapping["cp"]) {
            $this->outSwitchPage($mapping["cp"]);
            $this->_tagcp = $mapping["cp"];
        }

        $code = $mapping["code"];
        if(isset($attributes) && is_array($attributes) && count($attributes) > 0) {
            $code |= 0x80;
        }

        if(!isset($nocontent) || !$nocontent)
            $code |= 0x40;

        $this->outByte($code);

        if($code & 0x80)
            $this->outAttributes($attributes);
    }

    /**
     * Outputs actual data
     *
     * @access private
     * @return
     */
    private function _content($content) {
        $this->logContent($content);
        $this->outByte(WBXML_STR_I);
        $this->outTermStr($content);
    }

    /**
     * Outputs an actual end tag
     *
     * @access private
     * @return
     */
    private function _endTag() {
        $this->logEndTag();
        $this->outByte(WBXML_END);
    }

    /**
     * Outputs a byte
     *
     * @param $byte
     *
     * @access private
     * @return
     */
    private function outByte($byte) {
        fwrite($this->_out, chr($byte));
    }

    /**
     * Outputs a string table
     *
     * @param $uint
     *
     * @access private
     * @return
     */
    private function outMBUInt($uint) {
        while(1) {
            $byte = $uint & 0x7f;
            $uint = $uint >> 7;
            if($uint == 0) {
                $this->outByte($byte);
                break;
            } else {
                $this->outByte($byte | 0x80);
            }
        }
    }

    /**
     * Outputs content with string terminator
     *
     * @param $content
     *
     * @access private
     * @return
     */
    private function outTermStr($content) {
        fwrite($this->_out, $content);
        fwrite($this->_out, chr(0));
    }

    /**
     * Output attributes
     * We don't actually support this, because to do so, we would have
     * to build a string table before sending the data (but we can't
     * because we're streaming), so we'll just send an END, which just
     * terminates the attribute list with 0 attributes.
     *
     * @access private
     * @return
     */
    private function outAttributes() {
        $this->outByte(WBXML_END);
    }

    /**
     * Switches the codepage
     *
     * @param $page
     *
     * @access private
     * @return
     */
    private function outSwitchPage($page) {
        $this->outByte(WBXML_SWITCH_PAGE);
        $this->outByte($page);
    }

    /**
     * Get the mapping for a tag
     *
     * @param $tag
     *
     * @access private
     * @return array
     */
    private function getMapping($tag) {
        $mapping = array();

        $split = $this->splitTag($tag);

        if(isset($split["ns"])) {
            $cp = $this->_dtd["namespaces"][$split["ns"]];
        }
        else {
            $cp = 0;
        }

        $code = $this->_dtd["codes"][$cp][$split["tag"]];

        $mapping["cp"] = $cp;
        $mapping["code"] = $code;

        return $mapping;
    }

    /**
     * Split a tag from a the fulltag (namespace + tag)
     *
     * @param $fulltag
     *
     * @access private
     * @return array        keys: 'ns' (namespace), 'tag' (tag)
     */
    private function splitTag($fulltag) {
        $ns = false;
        $pos = strpos($fulltag, chr(58)); // chr(58) == ':'

        if($pos) {
            $ns = substr($fulltag, 0, $pos);
            $tag = substr($fulltag, $pos+1);
        }
        else {
            $tag = $fulltag;
        }

        $ret = array();
        if($ns)
            $ret["ns"] = $ns;
        $ret["tag"] = $tag;

        return $ret;
    }

    /**
     * Logs a StartTag to ZLog
     *
     * @param $tag
     * @param $attr
     * @param $nocontent
     *
     * @access private
     * @return
     */
    private function logStartTag($tag, $attr, $nocontent) {
        if(!WBXML_DEBUG)
            return;

        $spaces = str_repeat(" ", count($this->logStack));
        if($nocontent)
            ZLog::Write(LOGLEVEL_WBXML,"O " . $spaces . " <$tag/>");
        else {
            array_push($this->logStack, $tag);
            ZLog::Write(LOGLEVEL_WBXML,"O " . $spaces . " <$tag>");
        }
    }

    /**
     * Logs a EndTag to ZLog
     *
     * @access private
     * @return
     */
    private function logEndTag() {
        if(!WBXML_DEBUG)
            return;

        $spaces = str_repeat(" ", count($this->logStack));
        $tag = array_pop($this->logStack);
        ZLog::Write(LOGLEVEL_WBXML,"O " . $spaces . "</$tag>");
    }

    /**
     * Logs content to ZLog
     *
     * @param $content
     *
     * @access private
     * @return
     */
    private function logContent($content) {
        if(!WBXML_DEBUG)
            return;

        $spaces = str_repeat(" ", count($this->logStack));
        ZLog::Write(LOGLEVEL_WBXML,"O " . $spaces . $content);
    }
}

?>