<?php
// $Id: saxparser.php,v 1.12 2005/08/05 05:28:12 skalpa Exp $
/*******************************************************************************
    Location: <b>xml/SaxParser.class</b><br>
     <br>
    Provides basic functionality to read and parse XML documents.  Subclasses
    must implement all the their custom handlers by using add* function methods.
    They may also use the handle*() methods to parse a specific XML begin and end
    tags, but this is not recommended as it is more difficult.<br>
    <br>
    Copyright &copy; 2001 eXtremePHP.  All rights reserved.<br>
    <br>
    @author Ken Egervari<br>
*******************************************************************************/

class SaxParser
{
    var $level;
    var $parser;

    var $isCaseFolding;
    var $targetEncoding;

    /* Custom Handler Variables */
    var $tagHandlers = array();

    /* Tag stack */
    var $tags = array();

    /* Xml Source Input */
    var $xmlInput;

    var $errors = array();

    /****************************************************************************
        Creates a SaxParser object using a FileInput to represent the stream
        of XML data to parse.  Use the static methods createFileInput or
        createStringInput to construct xml input source objects to supply
        to the constructor, or the implementor can construct them individually.
    ****************************************************************************/
    function SaxParser(&$input)
    {
        $this->level = 0;
        $this->parser = xml_parser_create('UTF-8');
        xml_set_object($this->parser, $this);
        $this->input =& $input;
        $this->setCaseFolding(false);
        $this->useUtfEncoding();
        xml_set_element_handler($this->parser, 'handleBeginElement','handleEndElement');
        xml_set_character_data_handler($this->parser, 'handleCharacterData');
        xml_set_processing_instruction_handler($this->parser, 'handleProcessingInstruction');
        xml_set_default_handler($this->parser, 'handleDefault');
        xml_set_unparsed_entity_decl_handler($this->parser, 'handleUnparsedEntityDecl');
        xml_set_notation_decl_handler($this->parser, 'handleNotationDecl');
        xml_set_external_entity_ref_handler($this->parser, 'handleExternalEntityRef');
    }

    /*---------------------------------------------------------------------------
        Property Methods
    ---------------------------------------------------------------------------*/

    function getCurrentLevel()
    {
        return $this->level;
    }

    /****************************************************************************
        * @param $isCaseFolding
        * @returns void
    ****************************************************************************/
    function setCaseFolding($isCaseFolding)
    {
        assert(is_bool($isCaseFolding));

        $this->isCaseFolding = $isCaseFolding;
        xml_parser_set_option($this->parser, XML_OPTION_CASE_FOLDING, $this->isCaseFolding);
    }

    /****************************************************************************
        * @returns void
    ****************************************************************************/
    function useIsoEncoding()
    {
        $this->targetEncoding = 'ISO-8859-1';
        xml_parser_set_option($this->parser, XML_OPTION_TARGET_ENCODING, $this->targetEncoding);
    }

    /****************************************************************************
        * @returns void
    ****************************************************************************/
    function useAsciiEncoding()
    {
        $this->targetEncoding = 'US-ASCII';
        xml_parser_set_option($this->parser, XML_OPTION_TARGET_ENCODING, $this->targetEncoding);
    }

    /****************************************************************************
        * @returns void
    ****************************************************************************/
    function useUtfEncoding()
    {
        $this->targetEncoding = 'UTF-8';
        xml_parser_set_option($this->parser, XML_OPTION_TARGET_ENCODING, $this->targetEncoding);
    }

    /****************************************************************************
        Returns the name of the xml tag being parsed
        * @returns string
    ****************************************************************************/
    function getCurrentTag()
    {
        return $this->tags[count($this->tags) - 1];
    }

    function getParentTag()
    {
        if (isset($this->tags[count($this->tags) - 2])) {
            return $this->tags[count($this->tags) - 2];
        }
        return false;
    }



    /*---------------------------------------------------------------------------
        Parser methods
    ---------------------------------------------------------------------------*/

    /****************************************************************************
        * @returns void
    ****************************************************************************/
    function parse()
    {
        if (!is_resource($this->input)) {
            if (!xml_parse($this->parser, $this->input)) {
                $this->setErrors($this->getXmlError());
                return false;
            }
            //if (!$fp = fopen($this->input, 'r')) {
            //    $this->setErrors('Could not open file: '.$this->input);
            //    return false;
            //}
        } else {
            while ($data = fread($this->input, 4096)) {
                if (!xml_parse($this->parser, str_replace("'", "&apos;", $data), feof($this->input))) {
                    $this->setErrors($this->getXmlError());
                    fclose($this->input);
                    return false;
                }
            }
            fclose($this->input);
        }
        return true;
    }

    /****************************************************************************
        * @returns void
    ****************************************************************************/
    function free()
    {
        xml_parser_free($this->parser);

        if (!method_exists($this, '__destruct')) {
            unset($this);
        }
        else {
            $this->__destruct();
        }
    }

    /****************************************************************************
        * @private
        * @returns string
    ****************************************************************************/
    function getXmlError()
    {
        return sprintf("XmlParse error: %s at line %d", xml_error_string(xml_get_error_code($this->parser)), xml_get_current_line_number($this->parser));
    }

    /*---------------------------------------------------------------------------
        Custom Handler Methods
    ---------------------------------------------------------------------------*/

    /****************************************************************************
        Adds a callback function to be called when a tag is encountered.<br>
        Functions that are added must be of the form:<br>
        <b>functionName( $attributes )</b>
        * @param $tagName string.  The name of the tag currently being parsed.
        * @param $functionName string.  The name of the function in XmlDocument's
        subclass.
        * @returns void
    ****************************************************************************/
    function addTagHandler(&$tagHandler)
    {
        $name = $tagHandler->getName();
        if (is_array($name)) {
            foreach ($name as $n) {
                $this->tagHandlers[$n] =& $tagHandler;
            }
        } else {
            $this->tagHandlers[$name] =& $tagHandler;
        }
    }


    /*---------------------------------------------------------------------------
        Private Handler Methods
    ---------------------------------------------------------------------------*/

    /****************************************************************************
        Callback function that executes whenever a the start of a tag
        occurs when being parsed.
        * @param $parser int.  The handle to the parser.
        * @param $tagName string.  The name of the tag currently being parsed.
        * @param $attributesArray attay.  The list of attributes associated with
        the tag.
        * @private
        * @returns void
    ****************************************************************************/
    function handleBeginElement($parser, $tagName, $attributesArray)
    {
        array_push($this->tags, $tagName);
        $this->level++;
        if (isset($this->tagHandlers[$tagName]) && is_subclass_of($this->tagHandlers[$tagName], 'xmltaghandler')) {
            $this->tagHandlers[$tagName]->handleBeginElement($this, $attributesArray);
        } else {
			$this->handleBeginElementDefault($parser, $tagName, $attributesArray);
		}
    }

    /****************************************************************************
        Callback function that executes whenever the end of a tag
        occurs when being parsed.
        * @param $parser int.  The handle to the parser.
        * @param $tagName string.  The name of the tag currently being parsed.
        * @private
        * @returns void
    ****************************************************************************/
    function handleEndElement($parser, $tagName)
    {
        array_pop($this->tags);
        if (isset($this->tagHandlers[$tagName]) && is_subclass_of($this->tagHandlers[$tagName], 'xmltaghandler')) {
            $this->tagHandlers[$tagName]->handleEndElement($this);
        } else {
			$this->handleEndElementDefault($parser, $tagName);
		}
        $this->level--;
    }

    /****************************************************************************
        Callback function that executes whenever character data is encountered
        while being parsed.
        * @param $parser int.  The handle to the parser.
        * @param $data string.  Character data inside the tag
        * @returns void
    ****************************************************************************/
    function handleCharacterData($parser, $data)
    {
        $tagHandler =& $this->tagHandlers[$this->getCurrentTag()];
        if (isset($tagHandler) && is_subclass_of($tagHandler, 'xmltaghandler')) {
            $tagHandler->handleCharacterData($this, $data);
        } else {
			$this->handleCharacterDataDefault($parser, $data);
		}
    }

    /****************************************************************************
        * @param $parser int.  The handle to the parser.
        * @returns void
    ****************************************************************************/
    function handleProcessingInstruction($parser, &$target, &$data)
    {
//        if($target == 'php') {
//            eval($data);
//        }
    }

    /****************************************************************************
        * @param $parser int.  The handle to the parser.
        * @returns void
    ****************************************************************************/
    function handleDefault($parser, $data)
    {

    }

    /****************************************************************************
        * @param $parser int.  The handle to the parser.
        * @returns void
    ****************************************************************************/
    function handleUnparsedEntityDecl($parser, $entityName, $base, $systemId, $publicId, $notationName)
    {

    }

    /****************************************************************************
        * @param $parser int.  The handle to the parser.
        * @returns void
    ****************************************************************************/
    function handleNotationDecl($parser, $notationName, $base, $systemId, $publicId)
    {

    }

    /****************************************************************************
        * @param $parser int.  The handle to the parser.
        * @returns void
    ****************************************************************************/
    function handleExternalEntityRef($parser, $openEntityNames, $base, $systemId, $publicId)
    {

    }

	/**
	 * The default tag handler method for a tag with no handler
	 *
	 * @abstract
	 */
	function handleBeginElementDefault($parser, $tagName, $attributesArray)
	{
	}

	/**
	 * The default tag handler method for a tag with no handler
	 *
	 * @abstract
	 */
	function handleEndElementDefault($parser, $tagName)
	{
	}

	/**
	 * The default tag handler method for a tag with no handler
	 *
	 * @abstract
	 */
	function handleCharacterDataDefault($parser, $data)
	{
	}

	/**
	 * Sets error messages
	 *
	 * @param	$error	string	an error message
	 */
    function setErrors($error)
    {
        $this->errors[] = trim($error);
    }

	/**
	 * Gets all the error messages
	 *
	 * @param	$ashtml	bool	return as html?
	 * @return	mixed
	 */
    function &getErrors($ashtml = true)
    {
        if (!$ashtml) {
            return $this->errors;
        } else {
        	$ret = '';
        	if (count($this->errors) > 0) {
            	foreach ($this->errors as $error) {
            	    $ret .= $error.'<br />';
            	}
        	}
        	return $ret;
        }
    }
}

?>