roman.php

apache windows下的一款好

<?php
//
// +----------------------------------------------------------------------+
// | PHP version 4.0                                                      |
// +----------------------------------------------------------------------+
// | Copyright (c) 1997-2001 The PHP Group                                |
// +----------------------------------------------------------------------+
// | This source file is subject to version 2.02 of the PHP license,      |
// | that is bundled with this package in the file LICENSE, and is        |
// | available at through the world-wide-web at                           |
// | http://www.php.net/license/2_02.txt.                                 |
// | If you did not receive a copy of the PHP license and are unable to   |
// | obtain it through the world-wide-web, please send a note to          |
// | [e-mail] so we can mail you a copy immediately.               |
// +----------------------------------------------------------------------+
// | Authors: Sterling Hughes <[e-mail]>                          |
// +----------------------------------------------------------------------+
//

require_once("PEAR.php");

// {{{ Numbers_Roman

/**
 * The Numbers_Roman class provides utilities to convert roman numerals to
 * arabic numbers and convert arabic numbers to roman numerals
 *
 * @access public
 * @author Sterling Hughes <[e-mail]>
 * @since  PHP 4.0.5
 */
class Numbers_Roman extends PEAR
{
    // {{{ toNumber()

    /**
     * Converts a roman numeral to a number
     *
     * @param  string  $roman The roman numeral to convert
     *
     * @return integer $num   The number corresponding to the
     *                        given roman numeral
     *
     * @access public
     * @author Sterling Hughes <[e-mail]>
     * @since  PHP 4.0.5
     */
    function toNumber($roman)
    {
        $conv = array(
            array("letter" => 'I', "number" => 1),
            array("letter" => 'V', "number" => 5),
            array("letter" => 'X', "number" => 10),
            array("letter" => 'L', "number" => 50),
            array("letter" => 'C', "number" => 100),
            array("letter" => 'D', "number" => 500),
            array("letter" => 'M', "number" => 1000),
            array("letter" => 0,   "number" => 0)
        );
        $arabic = 0;
        $state  = 0;
        $sidx   = 0;
        $len    = strlen($roman) - 1;

        while ($len >= 0) {
            $i = 0;
            $sidx = $len;

            while ($conv[$i]['number'] > 0) {
                if (strtoupper($roman[$sidx]) == $conv[$i]['letter']) {
                    if ($state > $conv[$i]['number']) {
                        $arabic -= $conv[$i]['number'];
                    } else {
                        $arabic += $conv[$i]['number'];
                        $state   = $conv[$i]['number'];
                    }
                }
                $i++;
            }

            $len--;
        }

        return($arabic);
    }

    // }}}
    // {{{ toRoman()

    /**
     * Converts a number to its roman numeral representation
     *
     * @param  integer $num   An integer between 0 and 3999 inclusive
     *                        that should be converted to a roman numeral
     *
     * @return string  $roman The corresponding roman numeral
     *
     * @access public
     * @author Sterling Hughes <[e-mail]>
     * @since  PHP 4.0.5
     */
    function toRoman($num) {
        $conv = array(10 => array('X', 'C', 'M'),
                      5  => array('V', 'L', 'D'),
                      1  => array('I', 'X', 'C'));
        $roman = '';

        if ($num < 0) {
            return '';
        }

        $num = (int) $num;

        $digit  = (int) ($num / 1000);
        $num   -= $digit * 1000;
        while ($digit > 0) {
            $roman .= 'M';
            $digit--;
        }

        for ($i = 2; $i >= 0; $i--) {
            $power = pow(10, $i);
            $digit = (int) ($num / $power);
            $num -= $digit * $power;

            if (($digit == 9) || ($digit == 4)) {
                $roman .= $conv[1][$i] . $conv[$digit+1][$i];
            } else {
                if ($digit >= 5) {
                    $roman .= $conv[5][$i];
                    $digit -= 5;
                }

                while ($digit > 0) {
                    $roman .= $conv[1][$i];
                    $digit--;
                }
            }
        }

        return $roman;
    }

    // }}}
}

// }}}
?>