<?php
/**
 * File contains the ezcArchivePaxHeader class.
 *
 * @package Archive
 * @version 1.2.2
 * @copyright Copyright (C) 2005-2007 eZ systems as. All rights reserved.
 * @license http://ez.no/licenses/new_bsd New BSD License
 * @access private
 */

/** 
 * The ezcArchivePaxHeader class represents the Tar Pax header.
 * 
 * ezcArchivePaxHeader can read the header from an ezcArchiveBlockFile or ezcArchiveEntry. 
 *
 * The values from the headers are directly accessible via the class properties, and allows
 * reading and writing to specific header values. 
 * 
 * The entire header can be appended to an ezcArchiveBlockFile again or written to an ezcArchiveFileStructure.  
 * Information may get lost, though. 
 *
 * The header is the {@link ezcArchiveUstarHeader} with extra header information described on the following webpage:
 * {@link http://www.opengroup.org/onlinepubs/009695399/utilities/pax.html}
 *
 * Currently, only the extended header is supported.
 *
 * @package Archive
 * @version 1.2.2
 * @access private
 */ 
class ezcArchivePaxHeader extends ezcArchiveUstarHeader
{
    // Inherited the documentation.
    public function __set( $name, $value )
    {
        return parent::__set( $name, $value );
    }

    // Inherited the documentation.
    public function __get( $name )
    {
        return parent::__get( $name );
    }


    /**
     * Returns an array with pax header information.
     *
     * This method reads an extended set of data from the ezcArchiveBlockFile $file and returns the values in an array.
     *
     * @param ezcArchiveBlockFile $file
     * @return array(string=>string)
     */
    protected function getPaxDecodedHeader( ezcArchiveBlockFile $file )
    {
        $result = array();

        // next block has the info.
        $file->next();  

        $data = $file->current();

        $offset = 0;
        
        while ( strcmp( $data[$offset], "\0" ) != 0 )
        {
            $space = strpos( $data, " ", $offset );

            $length = substr( $data, $offset, $space - $offset );
            $equalSign = strpos( $data, "=",  $space );

            $keyword = substr( $data, $space + 1, $equalSign - $space - 1 );

            $value = rtrim( substr( $data, $equalSign + 1, $length - $equalSign - 1 ), "\n" );

            $result[ $keyword ] = $value;

            $offset += $length; 
        }

        return $result;
    }


    // Inherited the documentation.
    public function __construct( ezcArchiveBlockFile $file = null )
    {
        if ( !is_null( $file ) )
        {
            parent::__construct( $file );

            if ( $this->type == "x" )
            {
                $paxArray = $this->getPaxDecodedHeader( $file );
                $file->next();
            }

            parent::__construct( $file );

            // Override some fields.
            foreach ( $paxArray as $key => $value )
            {
                switch ( $key )
                {
                    case "gid": $this->groupId = $value;  break;  // For group IDs larger than 2097151.
                    case "linkpath": $this->linkName = $value;  break;  // Long link names?
                    case "path": $this->fileName = $value; $this->filePrefix = ""; break; // Really long file names.
                    case "size": $this->size = $value;  break;  // For files with a size greater than 8589934591 bytes.
                    case "uid": $this->userId = $value; break;  // For user IDs larger than 2097151. 
                }
            }
         }
    }

}

?>