<?php
// ***** BEGIN LICENSE BLOCK *****
// Version: MPL 1.1/GPL 2.0/LGPL 2.1
//
// The contents of this file are subject to the Mozilla Public License Version
// 1.1 (the "License"); you may not use this file except in compliance with
// the License. You may obtain a copy of the License at
// http://www.mozilla.org/MPL/
//
// Software distributed under the License is distributed on an "AS IS" basis,
// WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
// for the specific language governing rights and limitations under the
// License.
//
// The Original Code is Mozilla Update.
//
// Contributor(s):
//        Benjamin Smedberg
//        Mike Morgan 
//
// Alternatively, the contents of this file may be used under the terms of
// either the GNU General Public License Version 2 or later (the "GPL"), or
// the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
// in which case the provisions of the GPL or the LGPL are applicable instead
// of those above. If you wish to allow use of your version of this file only
// under the terms of either the GPL or the LGPL, and not to allow others to
// use your version of this file under the terms of the MPL, indicate your
// decision by deleting the provisions above and replace them with the notice
// and other provisions required by the GPL or the LGPL. If you do not delete
// the provisions above, a recipient may use your version of this file under
// the terms of any one of the MPL, the GPL or the LGPL.
//
// ***** END LICENSE BLOCK *****

/**
 * Version comparison script.  The purpose of this file is to mimic the C++
 * version comparison algorithm so version comparisons in VersionCheck.php are
 * properly executed with expected results.  This could have been accomplished
 * by establishing a standardized versioning scheme across all Mozilla
 * operations, but although that would make more sense, it's simply too late
 * for that now.  We cannot escape this.
 *
 * @package umo
 * @subpackage core
 */

/**
 * Parse a version part. 
 * @return array $r parsed version part.
 */
function NS_ParseVersionPart($p) {
    if ($p == '*') {
        return array('numA'   => 2147483647,
                     'strB'   => '',
                     'numC'   => 0,
                     'extraD' => '');
    }

    preg_match('/^([-\d]*)([^-\d]*)([-\d]*)(.*)$/', $p, $m);

    $r = array('numA'   => intval($m[1]),
               'strB'   => $m[2],
               'numC'   => intval($m[3]),
               'extraD' => $m[4]);

    if ($r['strB'] == '+') {
        ++$r['numA'];
        $r['strB'] = 'pre';
    }

    return $r;
}

/**
 * Compare parsed version parts.
 * @param string $an
 * @param string $bp
 * @return int $r
 */
function NS_cmp($an, $bn) {
    if ($an < $bn)
        return -1;

    if ($an > $bn)
        return 1;

    return 0;
}

/**
 * Recursive string comparison.
 * @param string $as
 * @param string $bs
 * @return int $r
 */
function NS_strcmp($as, $bs) {
    if ($as == $bs)
        return 0;

    if ($as == '')
        return 1;

    if ($bs == '')
        return -1;

    return strcmp($as, $bs);
}

/**
 * Compare parsed version numbers.
 * @param string $ap
 * @param string $bp
 * @return int $r -1|0|1
 */
function NS_CompareVersionParts($ap, $bp) {
    $avp = NS_ParseVersionPart($ap);
    $bvp = NS_ParseVersionPart($bp);

    $r = NS_cmp($avp['numA'], $bvp['numA']);
    if ($r)
        return $r;

    $r = NS_strcmp($avp['strB'], $bvp['strB']);
    if ($r)
        return $r;

    $r = NS_cmp($avp['numC'], $bvp['numC']);
    if ($r)
        return $r;

    return NS_strcmp($avp['extraD'], $bvp['extraD']);
}

/**
 * Master comparison function.
 * @param string $a complete version string.
 * @param string $b complete version string.
 * @return int $r -1|0|1
 */
function NS_CompareVersions($a, $b) {
    $al = explode('.', $a);
    $bl = explode('.', $b);

    while (count($al) || count($bl)) {
        $ap = array_shift($al);
        $bp = array_shift($bl);

        $r = NS_CompareVersionParts($ap, $bp);
        if ($r != 0)
            return $r;
    }

    return 0;
}
?>