PHP xml与数组之间的转换

/**
 * xml2array() will convert the given XML text to an array in the XML structure.
 * Link: http://www.bin-co.com/php/scripts/xml2array/
 * Arguments : $contents - The XML text
 * $get_attributes - 1 or 0. If this is 1 the function will get the attributes as well as the tag values - this results in a different array structure in the return value.
 * $priority - Can be 'tag' or 'attribute'. This will change the way the resulting array sturcture. For 'tag', the tags are given more importance.
 * Return: The parsed XML in an array form. Use print_r() to see the resulting array structure.
 * Examples: $array = xml2array(file_get_contents('feed.xml'));
 * $array = xml2array(file_get_contents('feed.xml', 1, 'attribute'));
 */
function xml2array( $contents , $get_attributes = 1, $priority = 'tag' ) {
  if (! $contents ) return array ();
  if (!function_exists( 'xml_parser_create' )) {
    // print "'xml_parser_create()' function not found!";
    return array ();
  }
  // Get the XML parser of PHP - PHP must have this module for the parser to work
  $parser = xml_parser_create( '' );
  xml_parser_set_option( $parser , XML_OPTION_TARGET_ENCODING, "UTF-8" ); //http://minutillo.com/steve/weblog/2004/6/17/php-xml-and-character-encodings-a-tale-of-sadness-rage-and-data-loss
  xml_parser_set_option( $parser , XML_OPTION_CASE_FOLDING, 0);
  xml_parser_set_option( $parser , XML_OPTION_SKIP_WHITE, 1);
  xml_parse_into_struct( $parser , trim( $contents ), $xml_values );
  xml_parser_free( $parser );
  if (! $xml_values ) return ; //Hmm...
  // Initializations
  $xml_array = array ();
  $parents = array ();
  $opened_tags = array ();
  $arr = array ();
  $current = & $xml_array ; //Refference
  // Go through the tags.
  $repeated_tag_index = array (); //Multiple tags with same name will be turned into an array
  foreach ( $xml_values as $data ) {
    unset( $attributes , $value ); //Remove existing values, or there will be trouble
    // This command will extract these variables into the foreach scope
    // tag(string), type(string), level(int), attributes(array).
    extract( $data ); //We could use the array by itself, but this cooler.
    $result = array ();
    $attributes_data = array ();
    if (isset( $value )) {
      if ( $priority == 'tag' ) $result = $value ;
      else $result [ 'value' ] = $value ; //Put the value in a assoc array if we are in the 'Attribute' mode
    }
    // Set the attributes too.
    if (isset( $attributes ) and $get_attributes ) {
      foreach ( $attributes as $attr => $val ) {
        if ( $priority == 'tag' ) $attributes_data [ $attr ] = $val ;
        else $result [ 'attr' ][ $attr ] = $val ; //Set all the attributes in a array called 'attr'
      }
    }
    // See tag status and do the needed.
    if ( $type == "open" ) { // The starting of the tag ''
      $parent [ $level -1] = & $current ;
      if (! is_array ( $current ) or (!in_array( $tag , array_keys ( $current )))) { // Insert New tag
        $current [ $tag ] = $result ;
        if ( $attributes_data ) $current [ $tag . '_attr' ] = $attributes_data ;
        $repeated_tag_index [ $tag . '_' . $level ] = 1;
        $current = & $current [ $tag ];
      } else { // There was another element with the same tag name
        if (isset( $current [ $tag ][0])) { // If there is a 0th element it is already an array
          $current [ $tag ][ $repeated_tag_index [ $tag . '_' . $level ]] = $result ;
          $repeated_tag_index [ $tag . '_' . $level ]++;
        } else { // This section will make the value an array if multiple tags with the same name appear together
          $current [ $tag ] = array ( $current [ $tag ], $result ); //This will combine the existing item and the new item together to make an array
          $repeated_tag_index [ $tag . '_' . $level ] = 2;
          if (isset( $current [ $tag . '_attr' ])) { // The attribute of the last(0th) tag must be moved as well
            $current [ $tag ][ '0_attr' ] = $current [ $tag . '_attr' ];
            unset( $current [ $tag . '_attr' ]);
          }
        }
        $last_item_index = $repeated_tag_index [ $tag . '_' . $level ]-1;
        $current = & $current [ $tag ][ $last_item_index ];
      }
    } elseif ( $type == "complete" ) { // Tags that ends in 1 line ''
      // See if the key is already taken.
      if (!isset( $current [ $tag ])) { // New Key
        $current [ $tag ] = $result ;
        $repeated_tag_index [ $tag . '_' . $level ] = 1;
        if ( $priority == 'tag' and $attributes_data ) $current [ $tag . '_attr' ] = $attributes_data ;
      } else { // If taken, put all things inside a list(array)
        if (isset( $current [ $tag ][0]) and is_array ( $current [ $tag ])) { // If it is already an array...
          // ...push the new element into that array.
          $current [ $tag ][ $repeated_tag_index [ $tag . '_' . $level ]] = $result ;
          if ( $priority == 'tag' and $get_attributes and $attributes_data ) {
            $current [ $tag ][ $repeated_tag_index [ $tag . '_' . $level ] . '_attr' ] = $attributes_data ;
          }
          $repeated_tag_index [ $tag . '_' . $level ]++;
        } else { // If it is not an array...
          $current [ $tag ] = array ( $current [ $tag ], $result ); //...Make it an array using using the existing value and the new value
          $repeated_tag_index [ $tag . '_' . $level ] = 1;
          if ( $priority == 'tag' and $get_attributes ) {
            if (isset( $current [ $tag . '_attr' ])) { // The attribute of the last(0th) tag must be moved as well
              $current [ $tag ][ '0_attr' ] = $current [ $tag . '_attr' ];
              unset( $current [ $tag . '_attr' ]);
            }
            if ( $attributes_data ) {
              $current [ $tag ][ $repeated_tag_index [ $tag . '_' . $level ] . '_attr' ] = $attributes_data ;
            }
          }
          $repeated_tag_index [ $tag . '_' . $level ]++; //0 and 1 index is already taken
        }
      }
    } elseif ( $type == 'close' ) { // End of tag ''
      $current = & $parent [ $level -1];
    }
  }
  return ( $xml_array );
}
// Array to XML
class array2xml {
  public $output = "\n" ;
  public $sub_item = array ();
  public function __construct( $array ) {
    $sub_item = array ();
    $this ->output .= $this ->xmlmake( $array );
  }
  public function xmlmake( $array , $fk = '' ) {
    $xml = '' ;
    global $sub_item ;
    foreach ( $array as $key => $value ) {
      if ( is_array ( $value )) {
        if ( is_numeric ( $key )) {
          $this ->sub_item= array_merge ( $this ->sub_item, array ( $fk ));
          $xml .= "<{$fk}>" . $this ->xmlmake( $value , $key ) . "" ;
        } else {
          $xml .= "<{$key}>" . $this ->xmlmake( $value , $key ) . "" ;
        }
      } else {
        $xml .= "<{$key}>{$value}\n" ;
      }
    }
    return $xml ;
  }
  public function output(){
    foreach ( $this ->sub_item as $t ){
      $this ->output = str_replace ( "<{$t}><{$t}>" , "<{$t}>" , $this ->output);
      $this ->output = str_replace ( "" , "" , $this ->output);
    }
    return $this ->output;
  }
}