php XML to array code conversion

// Convert Xml to array, including root keys, ignoring empty elements and attributes, there are still major errors
function xml_to_array( $xml )
{
 $reg = "/ <(\w+)[^>]*?>([\x00-\xFF]*?)<\/\1>/";
 if(preg_match_all($reg, $xml, $matches) )
 {
 $count = count($matches[0]);
 $arr = array();
 for($i = 0; $i < $count; $i++)
 {
 $key = $matches [1][$i];
 $val = xml_to_array( $matches[2][$i] ); // Recursion
 if(array_key_exists($key, $arr))
 {
 if(is_array($arr[ $key]))
 {
 if(!array_key_exists(0,$arr[$key]))
 {
 $arr[$key] = array($arr[$key]);
 }
 }else{
 $arr[$key] = array($arr[$key]);
 }
 $arr[$key][] = $val;
 }else{
 $arr[$key] = $val;
 }
 }
 return $arr;
 }else{
 return $xml;
 }
}
// Xml to array, excluding root key
function xmltoarray( $xml )
{
 $ arr = xml_to_array($xml);
 $key = array_keys($arr);
 return $arr[$key[0]];
}
// XPATH-like array selector
function xml_array_select( $arr, $arrpath )
{
 $arrpath = trim( $arrpath, '/' );
 if(!$arrpath) return $arr;
 $self = 'xml_array_select';

 $pos = strpos( $arrpath, '/' );
 $pos = $pos ? $pos : strlen($arrpath);
 $curpath = substr($arrpath, 0, $pos);
 $next = substr($arrpath, $pos);

 if(preg_match("/\[(\d+)\]$/",$curpath,$predicate))
 {
 $curpath = substr($curpath, 0, strpos($curpath," [{$predicate[1]}]"));
 $result = $arr[$curpath][$predicate[1]];
 }else $result = $arr[$curpath];

 if( is_array( $arr) && !array_key_exists($curpath, $arr) )
 {
 die( 'key is not exists:' . $curpath );
 }

 return $self($result, $next);
}< /p>
// If the input array is an all-numeric key, then the element values ​​will be transferred to $callback in sequence, otherwise it will transfer itself to $callback
function xml_array_each( $arr, $callback )
{
 if (func_num_args()<2) die('parameters error');
 if(!is_array($arr)) die('parameter 1 shuld be an array!');
 if(!is_callable($callback)) die ('parameter 2 shuld be an function!');
 $keys = array_keys($arr);
 $isok = true;
 foreach( $keys as $key ) {if(!is_int($key)) {$isok = false; break;}}
 if($isok)
 foreach( $arr as $val ) $result[] = $callback($val);
 else
 $result[] = $callback( $arr );
 return $result;
}
?>