--- /dev/null
+<?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 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 for dealing with Exif entries.
+ *
+ * This file defines two exception classes and the abstract class
+ * {@link PelEntry} which provides the basic methods that all Exif
+ * entries will have. All Exif entries will be represented by
+ * descendants of the {@link PelEntry} class --- the class itself is
+ * abstract and so it cannot be instantiated.
+ *
+ * @author Martin Geisler <mgeisler@users.sourceforge.net>
+ * @license http://www.gnu.org/licenses/gpl.html GNU General Public
+ * License (GPL)
+ * @package PEL
+ */
+
+/**
+ * Common ancestor class of all {@link PelIfd} entries.
+ *
+ * As this class is abstract you cannot instantiate objects from it.
+ * It only serves as a common ancestor to define the methods common to
+ * all entries. The most important methods are {@link getValue()} and
+ * {@link setValue()}, both of which is abstract in this class. The
+ * descendants will give concrete implementations for them.
+ *
+ * If you have some data coming from an image (some raw bytes), then
+ * the static method {@link newFromData()} is helpful --- it will look
+ * at the data and give you a proper decendent of {@link PelEntry}
+ * back.
+ *
+ * If you instead want to have an entry for some data which take the
+ * form of an integer, a string, a byte, or some other PHP type, then
+ * don't use this class. You should instead create an object of the
+ * right subclass ({@link PelEntryShort} for short integers, {@link
+ * PelEntryAscii} for strings, and so on) directly.
+ *
+ * @author Martin Geisler <mgeisler@users.sourceforge.net>
+ * @package PEL
+ */
+abstract class PelEntry
+{
+
+ /**
+ * Type of IFD containing this tag.
+ *
+ * This must be one of the constants defined in {@link PelIfd}:
+ * {@link PelIfd::IFD0} for the main image IFD, {@link PelIfd::IFD1}
+ * for the thumbnail image IFD, {@link PelIfd::EXIF} for the Exif
+ * sub-IFD, {@link PelIfd::GPS} for the GPS sub-IFD, or {@link
+ * PelIfd::INTEROPERABILITY} for the interoperability sub-IFD.
+ *
+ * @var int
+ */
+ protected $ifd_type;
+
+ /**
+ * The bytes representing this entry.
+ *
+ * Subclasses must either override {@link getBytes()} or, if
+ * possible, maintain this property so that it always contains a
+ * true representation of the entry.
+ *
+ * @var string
+ */
+ protected $bytes = '';
+
+ /**
+ * The {@link PelTag} of this entry.
+ *
+ * @var PelTag
+ */
+ protected $tag;
+
+ /**
+ * The {@link PelFormat} of this entry.
+ *
+ * @var PelFormat
+ */
+ protected $format;
+
+ /**
+ * The number of components of this entry.
+ *
+ * @var int
+ */
+ protected $components;
+
+ /**
+ * Return the tag of this entry.
+ *
+ * @return PelTag the tag of this entry.
+ */
+ public function getTag()
+ {
+ return $this->tag;
+ }
+
+ /**
+ * Return the type of IFD which holds this entry.
+ *
+ * @return int one of the constants defined in {@link PelIfd}:
+ * {@link PelIfd::IFD0} for the main image IFD, {@link PelIfd::IFD1}
+ * for the thumbnail image IFD, {@link PelIfd::EXIF} for the Exif
+ * sub-IFD, {@link PelIfd::GPS} for the GPS sub-IFD, or {@link
+ * PelIfd::INTEROPERABILITY} for the interoperability sub-IFD.
+ */
+ public function getIfdType()
+ {
+ return $this->ifd_type;
+ }
+
+ /**
+ * Update the IFD type.
+ *
+ * @param
+ * int must be one of the constants defined in {@link
+ * PelIfd}: {@link PelIfd::IFD0} for the main image IFD, {@link
+ * PelIfd::IFD1} for the thumbnail image IFD, {@link PelIfd::EXIF}
+ * for the Exif sub-IFD, {@link PelIfd::GPS} for the GPS sub-IFD, or
+ * {@link PelIfd::INTEROPERABILITY} for the interoperability
+ * sub-IFD.
+ */
+ public function setIfdType($type)
+ {
+ $this->ifd_type = $type;
+ }
+
+ /**
+ * Return the format of this entry.
+ *
+ * @return PelFormat the format of this entry.
+ */
+ public function getFormat()
+ {
+ return $this->format;
+ }
+
+ /**
+ * Return the number of components of this entry.
+ *
+ * @return int the number of components of this entry.
+ */
+ public function getComponents()
+ {
+ return $this->components;
+ }
+
+ /**
+ * Turn this entry into bytes.
+ *
+ * @param
+ * PelByteOrder the desired byte order, which must be either
+ * {@link Convert::LITTLE_ENDIAN} or {@link Convert::BIG_ENDIAN}.
+ *
+ * @return string bytes representing this entry.
+ */
+ public function getBytes($o)
+ {
+ return $this->bytes;
+ }
+
+ /**
+ * Get the value of this entry as text.
+ *
+ * The value will be returned in a format suitable for presentation,
+ * e.g., rationals will be returned as 'x/y', ASCII strings will be
+ * returned as themselves etc.
+ *
+ * @param
+ * boolean some values can be returned in a long or more
+ * brief form, and this parameter controls that.
+ *
+ * @return string the value as text.
+ */
+ abstract public function getText($brief = false);
+
+ /**
+ * Get the value of this entry.
+ *
+ * The value returned will generally be the same as the one supplied
+ * to the constructor or with {@link setValue()}. For a formatted
+ * version of the value, one should use {@link getText()} instead.
+ *
+ * @return mixed the unformatted value.
+ */
+ abstract public function getValue();
+
+ /**
+ * Set the value of this entry.
+ *
+ * The value should be in the same format as for the constructor.
+ *
+ * @param
+ * mixed the new value.
+ *
+ * @abstract
+ *
+ */
+ public function setValue($value)
+ {
+ /*
+ * This (fake) abstract method is here to make it possible for the
+ * documentation to refer to PelEntry::setValue().
+ * It cannot declared abstract in the proper PHP way, for then PHP
+ * wont allow subclasses to define it with two arguments (which is
+ * what PelEntryCopyright does).
+ */
+ throw new PelException('setValue() is abstract.');
+ }
+
+ /**
+ * Turn this entry into a string.
+ *
+ * @return string a string representation of this entry. This is
+ * mostly for debugging.
+ */
+ public function __toString()
+ {
+ $str = Pel::fmt(" Tag: 0x%04X (%s)\n", $this->tag, PelTag::getName($this->ifd_type, $this->tag));
+ $str .= Pel::fmt(" Format : %d (%s)\n", $this->format, PelFormat::getName($this->format));
+ $str .= Pel::fmt(" Components: %d\n", $this->components);
+ if ($this->getTag() != PelTag::MAKER_NOTE && $this->getTag() != PelTag::PRINT_IM) {
+ $str .= Pel::fmt(" Value : %s\n", print_r($this->getValue(), true));
+ }
+ $str .= Pel::fmt(" Text : %s\n", $this->getText());
+ return $str;
+ }
+}
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