<?php

/*  PEL: PHP Exif Library.  A library with support for reading and
 *  writing all Exif headers in JPEG and TIFF images using PHP.
 *
 *  Copyright (C) 2004, 2005, 2006, 2007  Martin Geisler.
 *
 *  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 in the file COPYING; if not, write to the
 *  Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
 *  Boston, MA 02110-1301 USA
 */

/* $Id$ */


/**
 * Classes used to hold ASCII strings.
 *
 * The classes defined here are to be used for Exif entries holding
 * ASCII strings, such as {@link PelTag::MAKE}, {@link
 * PelTag::SOFTWARE}, and {@link PelTag::DATE_TIME}.  For
 * entries holding normal textual ASCII strings the class {@link
 * PelEntryAscii} should be used, but for entries holding
 * timestamps the class {@link PelEntryTime} would be more
 * convenient instead.  Copyright information is handled by the {@link
 * PelEntryCopyright} class.
 *
 * @author Martin Geisler <mgeisler@users.sourceforge.net>
 * @version $Revision$
 * @date $Date$
 * @license http://www.gnu.org/licenses/gpl.html GNU General Public
 * License (GPL)
 * @package PEL
 */

/**#@+ Required class definitions. */
require_once('PelEntry.php');
/**#@-*/


/**
 * Class for holding a plain ASCII string.
 *
 * This class can hold a single ASCII string, and it will be used as in
 * <code>
 * $entry = $ifd->getEntry(PelTag::IMAGE_DESCRIPTION);
 * print($entry->getValue());
 * $entry->setValue('This is my image.  I like it.');
 * </code>
 *
 * @author Martin Geisler <mgeisler@users.sourceforge.net>
 * @package PEL
 */
class PelEntryAscii extends PelEntry {

  /**
   * The string hold by this entry.
   *
   * This is the string that was given to the {@link __construct
   * constructor} or later to {@link setValue}, without any final NULL
   * character.
   *
   * @var string
   */
  private $str;


  /**
   * Make a new PelEntry that can hold an ASCII string.
   *
   * @param int the tag which this entry represents.  This should be
   * one of the constants defined in {@link PelTag}, e.g., {@link
   * PelTag::IMAGE_DESCRIPTION}, {@link PelTag::MODEL}, or any other
   * tag with format {@link PelFormat::ASCII}.
   *
   * @param string the string that this entry will represent.  The
   * string must obey the same rules as the string argument to {@link
   * setValue}, namely that it should be given without any trailing
   * NULL character and that it must be plain 7-bit ASCII.
   */
  function __construct($tag, $str = '') {
    $this->tag    = $tag;
    $this->format = PelFormat::ASCII;
    self::setValue($str);
  }


  /**
   * Give the entry a new ASCII value.
   *
   * This will overwrite the previous value.  The value can be
   * retrieved later with the {@link getValue} method.
   *
   * @param string the new value of the entry.  This should be given
   * without any trailing NULL character.  The string must be plain
   * 7-bit ASCII, the string should contain no high bytes.
   *
   * @todo Implement check for high bytes?
   */
  function setValue($str) {
    $this->components = strlen($str)+1;
    $this->str        = $str;
    $this->bytes      = $str . chr(0x00);
  }


  /**
   * Return the ASCII string of the entry.
   *
   * @return string the string held, without any final NULL character.
   * The string will be the same as the one given to {@link setValue}
   * or to the {@link __construct constructor}.
   */
  function getValue() {
    return $this->str;
  }


  /**
   * Return the ASCII string of the entry.
   *
   * This methods returns the same as {@link getValue}.
   *
   * @param boolean not used with ASCII entries.
   *
   * @return string the string held, without any final NULL character.
   * The string will be the same as the one given to {@link setValue}
   * or to the {@link __construct constructor}.
   */
  function getText($brief = false) {
    return $this->str;      
  }

}


/**
 * Class for holding a date and time.
 *
 * This class can hold a timestamp, and it will be used as
 * in this example where the time is advanced by one week:
 * <code>
 * $entry = $ifd->getEntry(PelTag::DATE_TIME_ORIGINAL);
 * $time = $entry->getValue();
 * print('The image was taken on the ' . date('jS', $time));
 * $entry->setValue($time + 7 * 24 * 3600);
 * </code>
 *
 * The example used a standard UNIX timestamp, which is the default
 * for this class.
 *
 * But the Exif format defines dates outside the range of a UNIX
 * timestamp (about 1970 to 2038) and so you can also get access to
 * the timestamp in two other formats: a simple string or a Julian Day
 * Count. Please see the Calendar extension in the PHP Manual for more
 * information about the Julian Day Count.
 *
 * @author Martin Geisler <mgeisler@users.sourceforge.net>
 * @package PEL
 */
class PelEntryTime extends PelEntryAscii {

  /**
   * Constant denoting a UNIX timestamp.
   */
  const UNIX_TIMESTAMP   = 1;
  /**
   * Constant denoting a Exif string.
   */
  const EXIF_STRING      = 2;
  /**
   * Constant denoting a Julian Day Count.
   */
  const JULIAN_DAY_COUNT = 3;

  /**
   * The Julian Day Count of the timestamp held by this entry.
   *
   * This is an integer counting the number of whole days since
   * January 1st, 4713 B.C. The fractional part of the timestamp held
   * by this entry is stored in {@link $seconds}.
   *
   * @var int
   */
  private $day_count;

  /**
   * The number of seconds into the day of the timestamp held by this
   * entry.
   *
   * The number of whole days is stored in {@link $day_count} and the
   * number of seconds left-over is stored here.
   *
   * @var int
   */
  private $seconds;


  /**
   * Make a new entry for holding a timestamp.
   *
   * @param int the Exif tag which this entry represents.  There are
   * only three standard tags which hold timestamp, so this should be
   * one of the constants {@link PelTag::DATE_TIME}, {@link
   * PelTag::DATE_TIME_ORIGINAL}, or {@link
   * PelTag::DATE_TIME_DIGITIZED}.
   *
   * @param int the timestamp held by this entry in the correct form
   * as indicated by the third argument. For {@link UNIX_TIMESTAMP}
   * this is an integer counting the number of seconds since January
   * 1st 1970, for {@link EXIF_STRING} this is a string of the form
   * 'YYYY:MM:DD hh:mm:ss', and for {@link JULIAN_DAY_COUNT} this is a
   * floating point number where the integer part denotes the day
   * count and the fractional part denotes the time of day (0.25 means
   * 6:00, 0.75 means 18:00).
   *
   * @param int the type of the timestamp. This must be one of
   * {@link UNIX_TIMESTAMP}, {@link EXIF_STRING}, or
   * {@link JULIAN_DAY_COUNT}.
   */
  function __construct($tag, $timestamp, $type = self::UNIX_TIMESTAMP) {
    parent::__construct($tag);
    $this->setValue($timestamp, $type);
  }

  
  /**
   * Return the timestamp of the entry.
   *
   * The timestamp held by this entry is returned in one of three
   * formats: as a standard UNIX timestamp (default), as a fractional
   * Julian Day Count, or as a string.
   *
   * @param int the type of the timestamp. This must be one of
   * {@link UNIX_TIMESTAMP}, {@link EXIF_STRING}, or
   * {@link JULIAN_DAY_COUNT}.
   *
   * @return int the timestamp held by this entry in the correct form
   * as indicated by the type argument. For {@link UNIX_TIMESTAMP}
   * this is an integer counting the number of seconds since January
   * 1st 1970, for {@link EXIF_STRING} this is a string of the form
   * 'YYYY:MM:DD hh:mm:ss', and for {@link JULIAN_DAY_COUNT} this is a
   * floating point number where the integer part denotes the day
   * count and the fractional part denotes the time of day (0.25 means
   * 6:00, 0.75 means 18:00).
   */
  function getValue($type = self::UNIX_TIMESTAMP) {
    switch ($type) {
    case self::UNIX_TIMESTAMP:
      $seconds = $this->convertJdToUnix($this->day_count);
      if ($seconds === false)
        /* We get false if the Julian Day Count is outside the range
         * of a UNIX timestamp. */ 
        return false;
      else
        return $seconds + $this->seconds;

    case self::EXIF_STRING:
      list($year, $month, $day) = $this->convertJdToGregorian($this->day_count);
      $hours   = (int)($this->seconds / 3600);
      $minutes = (int)($this->seconds % 3600 / 60);
      $seconds = $this->seconds % 60;
      return sprintf('%04d:%02d:%02d %02d:%02d:%02d',
                     $year, $month, $day, $hours, $minutes, $seconds);
    case self::JULIAN_DAY_COUNT:
      return $this->day_count + $this->seconds / 86400;
    default:
      throw new PelInvalidArgumentException('Expected UNIX_TIMESTAMP (%d), ' .
                                            'EXIF_STRING (%d), or ' .
                                            'JULIAN_DAY_COUNT (%d) for $type, '.
                                            'got %d.',
                                            self::UNIX_TIMESTAMP,
                                            self::EXIF_STRING,
                                            self::JULIAN_DAY_COUNT,
                                            $type);
    }
  }


  /**
   * Update the timestamp held by this entry.
   *
   * @param int the timestamp held by this entry in the correct form
   * as indicated by the third argument. For {@link UNIX_TIMESTAMP}
   * this is an integer counting the number of seconds since January
   * 1st 1970, for {@link EXIF_STRING} this is a string of the form
   * 'YYYY:MM:DD hh:mm:ss', and for {@link JULIAN_DAY_COUNT} this is a
   * floating point number where the integer part denotes the day
   * count and the fractional part denotes the time of day (0.25 means
   * 6:00, 0.75 means 18:00).
   *
   * @param int the type of the timestamp. This must be one of
   * {@link UNIX_TIMESTAMP}, {@link EXIF_STRING}, or
   * {@link JULIAN_DAY_COUNT}.
   */
  function setValue($timestamp, $type = self::UNIX_TIMESTAMP) {
    #if (empty($timestamp))
    #  debug_print_backtrace();

    switch ($type) {
    case self::UNIX_TIMESTAMP:
      $this->day_count = $this->convertUnixToJd($timestamp);
      $this->seconds   = $timestamp % 86400;
      break;

    case self::EXIF_STRING:
      /* Clean the timestamp: some timestamps are broken other
       * separators than ':' and ' '. */
      $d = preg_split('/[^0-9]+/', $timestamp);
      $this->day_count = $this->convertGregorianToJd($d[0], $d[1], $d[2]);
      $this->seconds   = $d[3]*3600 + $d[4]*60 + $d[5];
      break;

    case self::JULIAN_DAY_COUNT:
      $this->day_count = (int)floor($timestamp);
      $this->seconds = (int)(86400 * ($timestamp - floor($timestamp)));
      break;

    default:
      throw new PelInvalidArgumentException('Expected UNIX_TIMESTAMP (%d), ' .
                                            'EXIF_STRING (%d), or ' .
                                            'JULIAN_DAY_COUNT (%d) for $type, '.
                                            'got %d.',
                                            self::UNIX_TIMESTAMP,
                                            self::EXIF_STRING,
                                            self::JULIAN_DAY_COUNT,
                                            $type);
    }

    /* Now finally update the string which will be used when this is
     * turned into bytes. */
    parent::setValue($this->getValue(self::EXIF_STRING));
  }


  // The following four functions are used for converting back and
  // forth between the date formats. They are used in preference to
  // the ones from the PHP calendar extension to avoid having to
  // fiddle with timezones and to avoid depending on the extension.
  //
  // See http://www.hermetic.ch/cal_stud/jdn.htm#comp for a reference.

  /**
   * Converts a date in year/month/day format to a Julian Day count.
   *
   * @param int $year  the year.
   * @param int $month the month, 1 to 12.
   * @param int $day   the day in the month.
   * @return int the Julian Day count.
   */
  function convertGregorianToJd($year, $month, $day) {
    // Special case mapping 0/0/0 -> 0
    if ($year == 0 || $month == 0 || $day == 0)
      return 0;

    $m1412 = ($month <= 2) ? -1 : 0;
    return floor(( 1461 * ( $year + 4800 + $m1412 ) ) / 4) +
      floor(( 367 * ( $month - 2 - 12 * $m1412 ) ) / 12) -
      floor(( 3 * floor( ( $year + 4900 + $m1412 ) / 100 ) ) / 4) +
      $day - 32075;
  }

  /**
   * Converts a Julian Day count to a year/month/day triple.
   * 
   * @param int the Julian Day count.
   * @return array an array with three entries: year, month, day.
   */
  function convertJdToGregorian($jd) {
    // Special case mapping 0 -> 0/0/0
    if ($jd == 0)
      return array(0,0,0);

    $l = $jd + 68569;
    $n = floor(( 4 * $l ) / 146097);
    $l = $l - floor(( 146097 * $n + 3 ) / 4);
    $i = floor(( 4000 * ( $l + 1 ) ) / 1461001);
    $l = $l - floor(( 1461 * $i ) / 4) + 31;
    $j = floor(( 80 * $l ) / 2447);
    $d = $l - floor(( 2447 * $j ) / 80);
    $l = floor($j / 11);
    $m = $j + 2 - ( 12 * $l );
    $y = 100 * ( $n - 49 ) + $i + $l;
    return array($y, $m, $d);
  }

  /**
   * Converts a UNIX timestamp to a Julian Day count.
   *
   * @param int $timestamp the timestamp.
   * @return int the Julian Day count.
   */
  function convertUnixToJd($timestamp) {
    return (int)(floor($timestamp / 86400) + 2440588);
  }

  /**
   * Converts a Julian Day count to a UNIX timestamp.
   *
   * @param int $jd the Julian Day count.

   * @return mixed $timestamp the integer timestamp or false if the
   * day count cannot be represented as a UNIX timestamp.
   */
  function convertJdToUnix($jd) {
    $timestamp = ($jd - 2440588) * 86400;
    if ($timestamp != (int)$timestamp)
      return false;
    else
      return $timestamp;
  }

}


/**
 * Class for holding copyright information.
 *
 * The Exif standard specifies a certain format for copyright
 * information where the one {@link PelTag::COPYRIGHT copyright
 * tag} holds both the photographer and editor copyrights, separated
 * by a NULL character.
 *
 * This class is used to manipulate that tag so that the format is
 * kept to the standard.  A common use would be to add a new copyright
 * tag to an image, since most cameras do not add this tag themselves.
 * This would be done like this:
 *
 * <code>
 * $entry = new PelEntryCopyright('Copyright, Martin Geisler, 2004');
 * $ifd0->addEntry($entry);
 * </code>
 *
 * Here we only set the photographer copyright, use the optional
 * second argument to specify the editor copyright.  If there is only
 * an editor copyright, then let the first argument be the empty
 * string.
 *
 * @author Martin Geisler <mgeisler@users.sourceforge.net>
 * @package PEL
 */
class PelEntryCopyright extends PelEntryAscii {

  /**
   * The photographer copyright.
   *
   * @var string
   */
  private $photographer;

  /**
   * The editor copyright.
   *
   * @var string
   */
  private $editor;


  /**
   * Make a new entry for holding copyright information.
   *
   * @param string the photographer copyright.  Use the empty string
   * if there is no photographer copyright.
   *
   * @param string the editor copyright.  Use the empty string if
   * there is no editor copyright.
   */
  function __construct($photographer = '', $editor = '') {
    parent::__construct(PelTag::COPYRIGHT);
    $this->setValue($photographer, $editor);
  }
  

  /**
   * Update the copyright information.
   *
   * @param string the photographer copyright.  Use the empty string
   * if there is no photographer copyright.
   *
   * @param string the editor copyright.  Use the empty string if
   * there is no editor copyright.
   */
  function setValue($photographer = '', $editor = '') {
    $this->photographer = $photographer;
    $this->editor       = $editor;

    if ($photographer == '' && $editor != '')
      $photographer = ' ';

    if ($editor == '')
      parent::setValue($photographer);
    else
      parent::setValue($photographer . chr(0x00) . $editor);
  }


  /**
   * Retrive the copyright information.
   *
   * The strings returned will be the same as the one used previously
   * with either {@link __construct the constructor} or with {@link
   * setValue}.
   *
   * @return array an array with two strings, the photographer and
   * editor copyrights.  The two fields will be returned in that
   * order, so that the first array index will be the photographer
   * copyright, and the second will be the editor copyright.
   */
  function getValue() {
    return array($this->photographer, $this->editor);
  }


  /**
   * Return a text string with the copyright information.
   *
   * The photographer and editor copyright fields will be returned
   * with a '-' in between if both copyright fields are present,
   * otherwise only one of them will be returned.
   *
   * @param boolean if false, then the strings '(Photographer)' and
   * '(Editor)' will be appended to the photographer and editor
   * copyright fields (if present), otherwise the fields will be
   * returned as is.
   *
   * @return string the copyright information in a string.
   */
  function getText($brief = false) {
    if ($brief) {
      $p = '';
      $e = '';
    } else {
      $p = ' ' . Pel::tra('(Photographer)');
      $e = ' ' . Pel::tra('(Editor)');
    }

    if ($this->photographer != '' && $this->editor != '')
      return $this->photographer . $p . ' - ' . $this->editor . $e;
    
    if ($this->photographer != '')
      return $this->photographer . $p;

    if ($this->editor != '')
      return $this->editor . $e;

    return '';
  }
}

?>