<?php

/******************************************************************************
*
* Filename:     get_ps_thumb.php
*
* Description:  This script extracts a Photoshop IRB (Image Resource Block)
*               thumbnail from within a JPEG file and allows it to be displayed
*
* Usage:        get_ps_thumb?filename=<filename>
*
* Author:       Evan Hunter
*
* Date:         23/7/2004
*
* Project:      PHP JPEG Metadata Toolkit
*
* Revision:     1.00
*
* URL:          http://electronics.ozhiker.com
*
* Copyright:    Copyright Evan Hunter 2004
*
* License:      This file is part of the PHP JPEG Metadata Toolkit.
*
*               The PHP JPEG Metadata Toolkit is free software; you can
*               redistribute it and/or modify it under the terms of the
*               GNU General Public License as published by the Free Software
*               Foundation; either version 2 of the License, or (at your
*               option) any later version.
*
*               The PHP JPEG Metadata Toolkit is distributed in the hope
*               that it will be useful, but WITHOUT ANY WARRANTY; without
*               even the implied warranty of MERCHANTABILITY or FITNESS
*               FOR A PARTICULAR PURPOSE.  See the GNU General Public License
*               for more details.
*
*               You should have received a copy of the GNU General Public
*               License along with the PHP JPEG Metadata Toolkit; if not,
*               write to the Free Software Foundation, Inc., 59 Temple
*               Place, Suite 330, Boston, MA  02111-1307  USA
*
*               If you require a different license for commercial or other
*               purposes, please contact the author: evan@ozhiker.com
*
******************************************************************************/

        // Ensure that nothing can write to the standard io, before we get the header out
        ob_start( );


        include 'JPEG.php';
        include 'Photoshop_IRB.php';

        // retrieve the filename from the URL parameters

        $filename = $GLOBALS['HTTP_GET_VARS']['filename'];
        
        // Retrieve the JPEG header Data

        $jpeg_header_data = get_jpeg_header_data( $filename );

        // Retrieve any Photoshop IRB data in the file

        $IRB_array = get_Photoshop_IRB( $jpeg_header_data );

        // Check if Photoshop IRB data was retrieved

        if ( $IRB_array === FALSE )
        {
                // No Photoshop IRB data could be retrieved - abort
                ob_end_clean ( );
                echo "<p>Photoshop IRB could not be retrieved</p>\n";
                return;
        }

        // Cycle through the resources in the Photoshop IRB
        // Until either a thumbnail resource is found or
        // there are no more resources
        $i = 0;
        while ( ( $i < count( $IRB_array ) ) &&
                ( $IRB_array[$i]['ResID'] != 0x0409 ) &&
                ( $IRB_array[$i]['ResID'] != 0x040C ) )
        {
                $i++;
        }


        // Check if a thumbnail was found
        if ( $i < count( $IRB_array ) )
        {
                // A thumbnail was found, Display it
                ob_end_clean ( );
                header("Content-type: image/jpeg");
                print substr( $IRB_array[$i]['ResData'] , 28 );
        }


?>
