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<?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 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
*/
/* $Id$ */
/**
* Namespace for functions operating on Exif formats.
*
* @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
*/
/**
* Namespace for functions operating on Exif formats.
*
* This class defines the constants that are to be used whenever one
* has to refer to the format of an Exif tag. They will be
* collectively denoted by the pseudo-type PelFormat throughout the
* documentation.
*
* All the methods defined here are static, and they all operate on a
* single argument which should be one of the class constants.
*
* @author Martin Geisler <mgeisler@users.sourceforge.net>
* @package PEL
*/
class PelFormat {
/**
* Unsigned byte.
*
* Each component will be an unsigned 8-bit integer with a value
* between 0 and 255.
*
* Modelled with the {@link PelEntryByte} class.
*/
const BYTE = 1;
/**
* ASCII string.
*
* Each component will be an ASCII character.
*
* Modelled with the {@link PelEntryAscii} class.
*/
const ASCII = 2;
/**
* Unsigned short.
*
* Each component will be an unsigned 16-bit integer with a value
* between 0 and 65535.
*
* Modelled with the {@link PelEntryShort} class.
*/
const SHORT = 3;
/**
* Unsigned long.
*
* Each component will be an unsigned 32-bit integer with a value
* between 0 and 4294967295.
*
* Modelled with the {@link PelEntryLong} class.
*/
const LONG = 4;
/**
* Unsigned rational number.
*
* Each component will consist of two unsigned 32-bit integers
* denoting the enumerator and denominator. Each integer will have
* a value between 0 and 4294967295.
*
* Modelled with the {@link PelEntryRational} class.
*/
const RATIONAL = 5;
/**
* Signed byte.
*
* Each component will be a signed 8-bit integer with a value
* between -128 and 127.
*
* Modelled with the {@link PelEntrySByte} class.
*/
const SBYTE = 6;
/**
* Undefined byte.
*
* Each component will be a byte with no associated interpretation.
*
* Modelled with the {@link PelEntryUndefined} class.
*/
const UNDEFINED = 7;
/**
* Signed short.
*
* Each component will be a signed 16-bit integer with a value
* between -32768 and 32767.
*
* Modelled with the {@link PelEntrySShort} class.
*/
const SSHORT = 8;
/**
* Signed long.
*
* Each component will be a signed 32-bit integer with a value
* between -2147483648 and 2147483647.
*
* Modelled with the {@link PelEntrySLong} class.
*/
const SLONG = 9;
/**
* Signed rational number.
*
* Each component will consist of two signed 32-bit integers
* denoting the enumerator and denominator. Each integer will have
* a value between -2147483648 and 2147483647.
*
* Modelled with the {@link PelEntrySRational} class.
*/
const SRATIONAL = 10;
/**
* Floating point number.
*
* Entries with this format are not currently implemented.
*/
const FLOAT = 11;
/**
* Double precision floating point number.
*
* Entries with this format are not currently implemented.
*/
const DOUBLE = 12;
/**
* Returns the name of a format.
*
* @param PelFormat the format.
*
* @return string the name of the format, e.g., 'Ascii' for the
* {@link ASCII} format etc.
*/
static function getName($type) {
switch ($type) {
case self::ASCII: return 'Ascii';
case self::BYTE: return 'Byte';
case self::SHORT: return 'Short';
case self::LONG: return 'Long';
case self::RATIONAL: return 'Rational';
case self::SBYTE: return 'SByte';
case self::SSHORT: return 'SShort';
case self::SLONG: return 'SLong';
case self::SRATIONAL: return 'SRational';
case self::FLOAT: return 'Float';
case self::DOUBLE: return 'Double';
case self::UNDEFINED: return 'Undefined';
default:
return Pel::fmt('Unknown format: 0x%X', $type);
}
}
/**
* Return the size of components in a given format.
*
* @param PelFormat the format.
*
* @return the size in bytes needed to store one component with the
* given format.
*/
static function getSize($type) {
switch ($type) {
case self::ASCII: return 1;
case self::BYTE: return 1;
case self::SHORT: return 2;
case self::LONG: return 4;
case self::RATIONAL: return 8;
case self::SBYTE: return 1;
case self::SSHORT: return 2;
case self::SLONG: return 4;
case self::SRATIONAL: return 8;
case self::FLOAT: return 4;
case self::DOUBLE: return 8;
case self::UNDEFINED: return 1;
default:
return Pel::fmt('Unknown format: 0x%X', $type);
}
}
}
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