<?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 for holding signed bytes.
 *
 * This class can hold bytes, either just a single byte or an array of
 * bytes. The class will be used to manipulate any of the Exif tags
 * which has format {@link PelFormat::BYTE}.
 *
 * @author Martin Geisler <mgeisler@users.sourceforge.net>
 * @package PEL
 */
class PelEntrySByte extends PelEntryNumber
{

    /**
     * Make a new entry that can hold a signed byte.
     *
     * The method accept several integer arguments. The {@link getValue}
     * method will always return an array except for when a single
     * integer argument is given here.
     *
     * @param int $tag
     *            the tag which this entry represents. This
     *            should be one of the constants defined in {@link PelTag}
     *            which has format {@link PelFormat::BYTE}.
     *
     * @param int $value...
     *            the byte(s) that this entry will represent.
     *            The argument passed must obey the same rules as the argument to
     *            {@link setValue}, namely that it should be within range of a
     *            signed byte, that is between -128 and 127 (inclusive). If not,
     *            then a {@link PelOverflowException} will be thrown.
     */
    public function __construct($tag, $value = null)
    {
        $this->tag = $tag;
        $this->min = - 128;
        $this->max = 127;
        $this->format = PelFormat::SBYTE;

        $value = func_get_args();
        array_shift($value);
        $this->setValueArray($value);
    }

    /**
     * Convert a number into bytes.
     *
     * @param int $number
     *            the number that should be converted.
     *
     * @param PelByteOrder $order
     *            one of {@link PelConvert::LITTLE_ENDIAN} and
     *            {@link PelConvert::BIG_ENDIAN}, specifying the target byte order.
     *
     * @return string bytes representing the number given.
     */
    public function numberToBytes($number, $order)
    {
        return chr($number);
    }
}