<?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
*/
namespace lsolesen\pel;
/**
* Classes used to hold bytes, both signed and unsigned.
* The {@link
* PelEntryWindowsString} class is used to manipulate strings in the
* format Windows XP needs.
*
* @author Martin Geisler <mgeisler@users.sourceforge.net>
* @license http://www.gnu.org/licenses/gpl.html GNU General Public
* License (GPL)
* @package PEL
*/
/**
* Class used to manipulate strings in the format Windows XP uses.
*
* When examining the file properties of an image in Windows XP one
* can fill in title, comment, author, keyword, and subject fields.
* Filling those fields and pressing OK will result in the data being
* written into the Exif data in the image.
*
* The data is written in a non-standard format and can thus not be
* loaded directly --- this class is needed to translate it into
* normal strings.
*
* It is important that entries from this class are only created with
* the {@link PelTag::XP_TITLE}, {@link PelTag::XP_COMMENT}, {@link
* PelTag::XP_AUTHOR}, {@link PelTag::XP_KEYWORD}, and {@link
* PelTag::XP_SUBJECT} tags. If another tag is used the data will no
* longer be correctly decoded when reloaded with PEL. (The data will
* be loaded as an {@link PelEntryByte} entry, which isn't as useful.)
*
* This class is to be used as in
* <code>
* $title = $ifd->getEntry(PelTag::XP_TITLE);
* print($title->getValue());
* $title->setValue('My favorite cat');
* </code>
* or if no entry is present one can add a new one with
* <code>
* $title = new PelEntryWindowsString(PelTag::XP_TITLE, 'A cute dog.');
* $ifd->addEntry($title);
* </code>
*
* @author Martin Geisler <mgeisler@users.sourceforge.net>
* @package PEL
*/
class PelEntryWindowsString extends PelEntry
{
const ZEROES = "\x0\x0";
/**
* 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 extra NULL
* characters or any such nonsense.
*
* @var string
*/
private $str;
/**
* Make a new PelEntry that can hold a Windows XP specific string.
*
* @param int $tag
* the tag which this entry represents. This should be
* one of {@link PelTag::XP_TITLE}, {@link PelTag::XP_COMMENT},
* {@link PelTag::XP_AUTHOR}, {@link PelTag::XP_KEYWORD}, and {@link
* PelTag::XP_SUBJECT} tags. If another tag is used, then this
* entry will be incorrectly reloaded as a {@link PelEntryByte}.
*
* @param string $str
* the string that this entry will represent. It will
* be passed to {@link setValue} and thus has to obey its
* requirements.
* @param bool $from_exif
* internal use only, tells that string is UCS-2LE encoded, as PHP fails to detect this encoding
*/
public function __construct($tag, $str = '', $from_exif = false)
{
$this->tag = $tag;
$this->format = PelFormat::BYTE;
$this->setValue($str, $from_exif);
}
/**
* Give the entry a new value.
*
* This will overwrite the previous value. The value can be
* retrieved later with the {@link getValue} method.
*
* @param string $str
* the new value of the entry.
* @param bool $from_exif
* internal use only, tells that string is UCS-2LE encoded, as PHP fails to detect this encoding
*/
public function setValue($str, $from_exif = false)
{
$zlen = strlen(static::ZEROES);
if (false !== $from_exif) {
$s = $str;
if (substr($str, -$zlen, $zlen) == static::ZEROES) {
$str = substr($str, 0, -$zlen);
}
$str = mb_convert_encoding($str, 'UTF-8', 'UCS-2LE');
} else {
$s = mb_convert_encoding($str, 'UCS-2LE', 'auto');
}
if (substr($s, -$zlen, $zlen) != static::ZEROES) {
$s .= static::ZEROES;
}
$l = strlen($s);
$this->components = $l;
$this->str = $str;
$this->bytes = $s;
}
/**
* Return the string of the entry.
*
* @return string the string held, without any extra NULL
* characters. The string will be the same as the one given to
* {@link setValue} or to the {@link __construct constructor}.
*/
public function getValue()
{
return $this->str;
}
/**
* Return the string of the entry.
*
* This methods returns the same as {@link getValue}.
*
* @param boolean $brief
* not used.
*
* @return string the string held, without any extra NULL
* characters. The string will be the same as the one given to
* {@link setValue} or to the {@link __construct constructor}.
*/
public function getText($brief = false)
{
return $this->str;
}
}
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