<? 
/***************************************************************************** 
 * $Title: XML parsing example: Collect statistics about a XML document $    * 
 * $Description:                                                             * 
 * This example uses PHP's expat parser to collect statistical information   *  
 * (like number of distinct elements, children and parents of elements)      * 
 * about a XML document.                                                     * 
 * Call it with the XML file to process as argument:                         * 
 * ./xmlstats_PHP4.php3 test.xml                                             * 
 *                                                                           * 
 * $Requires: Expat                                                          * 
 *            PHP 4.0 built as CGI binary $                                  * 
 *                                                                           * 
 *****************************************************************************/ 

// The first argument is the file to process 
$file = "may.xml"; 

// Initialize variables 
$elements = $stack = array(); 
$total_elements = $total_chars = 0; 

// The base class for an element 
class element 
{ 
    var $count = 0; 
    var $chars = 0; 
    var $parents = array(); 
    var $childs = array(); 
} 

// Utility function to parse a XML document from a file 
function xml_parse_from_file($parser, $file) 
{ 
    if(!file_exists($file)) 
    { 
        die("Can't find file \"$file\"."); 
    } 
     
    if(!($fp = @fopen($file, "r")))  
    { 
        die("Can't open file \"$file\"."); 
    } 
     
    while($data = fread($fp, 4096)) 
    { 
        if(!xml_parse($parser, $data, feof($fp))) 
        { 
            return(false); 
        } 
    } 
     
    fclose($fp); 
     
    return(true); 
} 

// Utility function to print a message in a box 
function print_box($title, $value) 
{ 
    printf("<br>+%'-60s+<br>", ""); 
    printf("|%20s", "$title:"); 
    printf("%14s", $value); 
    printf("%26s|<br>", ""); 
    printf("+%'-60s+<br>", "");     
} 

// Utility function to print a line 
function print_line($title, $value) 
{ 
    printf("%20s", "$title:"); 
    printf("%15s<br>", $value); 
} 

// Sort function for usasort() 
function my_sort($a, $b) 
{ 
    return(is_object($a) && is_object($b) ? $b->count - $a->count: 0); 
} 

function start_element($parser, $name, $attrs) 
{ 
    global $elements, $stack; 
     
    // Does this element already exist in the global $elements array? 
    if(!isset($elements[$name])) 
    { 
        // No - add a new instance of class element 
        $element = new element; 
        $elements[$name] = $element; 
    } 

    // Increase this elements count 
    $elements[$name]->count++; 
         
    // Is there a parent element? 
    if(isset($stack[count($stack)-1])) 
    { 
        // Yes - set $last_element to the parent 
        $last_element = $stack[count($stack)-1]; 
     
        // If there is no entry for the parent element in the current 
        // element's parents array, initialize it to 0 
        if(!isset($elements[$name]->parents[$last_element])) 
        { 
            $elements[$name]->parents[$last_element] = 0; 
        } 
         
        // Increase the count for this element's parent 
        $elements[$name]->parents[$last_element]++; 
     
        // If there is no entry for this element in the parent's 
        // elements' child array, initialize it to 0 
        if(!isset($elements[$last_element]->childs[$name])) 
        { 
            $elements[$last_element]->childs[$name] = 0; 
        } 

        // Increase the count for this element parent in the parent's 
        // childs array 
        $elements[$last_element]->childs[$name]++; 
    } 
     
    // Add current element to the stack 
    array_push($stack, $name);     
} 

function stop_element($parser, $name) 
{ 
    global $stack; 

    // Remove last element from the stack 
    array_pop($stack); 
} 

function char_data($parser, $data) 
{ 
    global $elements, $stack, $depth; 
     
    // Increase character count for the current element 
    $elements[$stack[count($stack)-1]]->chars += strlen(trim($data)); 
} 

// Create Expat parser 
$parser = xml_parser_create(); 

// Set handler functions 
xml_set_element_handler($parser, "start_element", "stop_element"); 
xml_set_character_data_handler($parser, "char_data"); 
xml_parser_set_option($parser, XML_OPTION_CASE_FOLDING, 0); 

// Parse the file 
$ret = xml_parse_from_file($parser, $file); 
if(!$ret) 
{ 
    die(sprintf("XML error: %s at line %d", 
                    xml_error_string(xml_get_error_code($parser)), 
                    xml_get_current_line_number($parser))); 
} 

// Free parser 
xml_parser_free($parser); 

// Free helper elements 
unset($elements["current_element"]); 
unset($elements["last_element"]); 

// Sort $elements array by element count 
uasort($elements, "my_sort"); 

// Loop through all elements collected in $elements 
while(list($name, $element) = each($elements)) 
{ 
    print_box("Element name", $name); 
     
    print_line("Element count", $element->count); 
    print_line("Character count", $element->chars); 
     
    printf("\n%20s\n", "* Parent elements"); 
     
    // Loop through the parents of this element, output them 
    while(list($key, $value) = each($element->parents)) 
    { 
        print_line($key, $value); 
    } 
    if(count($element->parents) == 0) 
    { 
        printf("%35s\n", "[root element]"); 
    } 

    // Loop through the childs of this element, output them     
    printf("<br>%20s<br>", "* Child elements"); 
    while(list($key, $value) = each($element->childs)) 
    { 
        print_line($key, $value); 
    }     
    if(count($element->childs) == 0) 
    { 
        printf("%35s<br>", "[no childs]"); 
    }     
     
    $total_elements += $element->count; 
    $total_chars += $element->chars; 
} 

// Final summary 
print_box("Total elements", $total_elements); 
print_box("Total characters", $total_chars); 
?>