<?php
########################################################################
#
# Project: FreeGallery
# URL: http://www.nabber.org/projects/
# E-mail: hide@address.com
#
# Copyright: (C) 2003-2010, Neil McNab
# License: GNU General Public License Version 2
#   (http://www.gnu.org/copyleft/gpl.html)
#
# This program 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.
#
# This program 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 this program; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
#
# Filename: $URL: https://freegallery.svn.sourceforge.net/svnroot/freegallery/releases/freegallery-2.0/includes/comment.php $
# Author(s): Neil McNab
# Last Updated: $Date: 2010-05-21 16:53:57 -0700 (Fri, 21 May 2010) $
#
# Description:
#   This file generates comments for a file or directory.
#
########################################################################

include_once('gallery_decode.php');

function get_comment($filename, $ext) {
  $comment = "";
  if (is_dir($filename)) {
    $comment = get_dir_comment($filename);
    if (empty($comment)) {
      $comment = get_galbum_comment($filename);
    }
  } else {
    // try different comment locations
    $comment = get_txt_comment($filename);

    if (empty($comment)) {
      $comment = get_gitem_comment($filename);
    }

    if (empty($comment)) {
      if ($ext == '.jpg' or $ext == '.jpeg' or image_type_to_mime_type($ext) == 'image/jpeg') {
        $comment = get_jpeg_comment($filename);
      }
      elseif ($ext == '.png' or image_type_to_mime_type($ext) == 'image/png') {
        $comment = get_png_comment($filename);
      }
    }

    // last resort, use filename as comment
    if (empty($comment)) {
      $comment = substr(basename($filename), 0, strrpos($filename, "."));
    }
  }

  return $comment;
}

function get_txt_comment($filename) {
    $textdesc = "";
    if (is_readable($filename . ".txt")) {
        $textdesc = file_get_contents($filename . ".txt");
    }
    return $textdesc;
}

function get_galbum_comment($filename) {
  $textdesc = '';
  if (!is_readable($filename . "/album.dat"))
    return $textdesc;

  $Album = get_object($filename . "/album.dat");
  if (isset($Album)) {
    $textdesc = $Album->fields['description'];
  }
  return $textdesc;
}

function get_gitem_comment($filename) {
  $textdesc = "";
  $dir = dirname($filename);
  if (!is_readable($dir . "/photos.dat"))
    return $textdesc;
  
  $AlbumItem = get_object($dir . "/photos.dat");
  if (isset($AlbumItem)) {
    for ($j = 0; $j < sizeof($AlbumItem); $j++) {
      if (!strcmp($AlbumItem[$j]->image->name . "." . $AlbumItem[$j]->image->type, basename($filename)))
        $textdesc =  $AlbumItem[$j]->caption;
    }
  }
  return $textdesc;
}

function get_dir_comment($filename) {
    $textdesc = "";
    if (is_readable($filename . "/desc.txt")) {
        $textdesc = file_get_contents($filename . "/desc.txt");
    }
    return $textdesc;
}

function get_jpeg_comment($filename) {

  $handle = fopen($filename, "rb");

  # get length
  fseek($handle, 0, SEEK_END);
  $fend = ftell($handle);

  # reset to start of file
  fseek($handle, 0, SEEK_SET);

  # first bytes of JPEG are always the same
  $header = fread($handle, 2);

  while(ftell($handle) <= $fend) {

    $type_code = fread($handle, 2);

    $charlength = fread($handle, 2);
    # Subtract off length bytes
    $length = ord($charlength[1]) + (ord($charlength[0]) << 8) - 2;

    # start of comment indicator
    if ((ord($type_code[0]) == 0xff) and (ord($type_code[1]) == 0xfe)) {
      $comment_field = fread($handle, $length);

      fclose($handle);
      return $comment_field;
    }
    else {
      fseek($handle, $length, SEEK_CUR);
    }
  }

  fclose($handle);
  return "";
}


function get_png_comment($filename) {
  # from RFC 2083

  $PNG_COMMENT = "comment";

  $crc_size = 4;

  $handle = fopen($filename, "rb");

  # get length
  fseek($handle, 0, SEEK_END);
  $fend = ftell($handle);

  # reset to start of file
  fseek($handle, 0, SEEK_SET);
  
  # first bytes of PNG are always the same
  $nullspace = fread($handle, 8);

  while(ftell($handle) <= $fend) {

    $charlength = fread($handle, 4);
    $length = ord($charlength[3]) + (ord($charlength[2]) << 8) + 
              (ord($charlength[1]) << 16) + (ord($charlength[0]) << 24);

    $type_code = fread($handle, 4);
  
    # start of comment indicator
    if ($type_code == "tEXt") {
      $comment_field = fread($handle, $length);
      
      # parse out keyword and comment data
      if (!strcasecmp(substr($comment_field, 0, strlen($PNG_COMMENT)), $PNG_COMMENT)) {
        $comment = substr($comment_field, strlen($PNG_COMMENT) + 1);
	
        fclose($handle);
        return $comment;
      }
    }
    else {
      fseek($handle, $length, SEEK_CUR);
    }
    
    # always remove CRC, we aren't checking it
    fseek($handle, $crc_size, SEEK_CUR);
  }

  fclose($handle);
  return "";
}

?>