Slugify for php

slugify.php

function slugify($string)
{
    $string = strip_tags($string);
    $string = remove_accents($string);


    $string = preg_replace('|%([a-fA-F0-9][a-fA-F0-9])|', '---$1---', $string);

    $string = str_replace('%', '', $string);

    $string = preg_replace('|---([a-fA-F0-9][a-fA-F0-9])---|', '%$1', $string);

    if (seems_utf8($string)) {
        if (function_exists('mb_strtolower')) {
            $string = mb_strtolower($string, 'UTF-8');
        }

    }

    $string = strtolower($string);
    $string = preg_replace('/&.+?;/', '', $string); // kill entities
    $string = str_replace('.', '-', $string);
    $string = preg_replace('/[^%a-z0-9 _-]/', '', $string);
    $string = preg_replace('/\s+/', '-', $string);
    $string = preg_replace('|-+|', '-', $string);
    $string = trim($string, '-');

    return $string;
}

function seems_utf8($str) {
    $length = strlen($str);
    for ($i=0; $i < $length; $i++) {
        $c = ord($str[$i]);
        if ($c < 0x80) $n = 0; # 0bbbbbbb
        elseif (($c & 0xE0) == 0xC0) $n=1; # 110bbbbb
        elseif (($c & 0xF0) == 0xE0) $n=2; # 1110bbbb
        elseif (($c & 0xF8) == 0xF0) $n=3; # 11110bbb
        elseif (($c & 0xFC) == 0xF8) $n=4; # 111110bb
        elseif (($c & 0xFE) == 0xFC) $n=5; # 1111110b
        else return false; # Does not match any model
        for ($j=0; $j<$n; $j++) { # n bytes matching 10bbbbbb follow ?
            if ((++$i == $length) || ((ord($str[$i]) & 0xC0) != 0x80))
                return false;
        }
    }
    return true;
}

function remove_accents($string) {
    if ( !preg_match('/[\x80-\xff]/', $string) )
        return $string;

    if (seems_utf8($string)) {
        $chars = array(
        // Decompositions for Latin-1 Supplement
        chr(195).chr(128) => 'A', chr(195).chr(129) => 'A',
        chr(195).chr(130) => 'A', chr(195).chr(131) => 'A',
        chr(195).chr(132) => 'A', chr(195).chr(133) => 'A',
        chr(195).chr(134) => 'AE',chr(195).chr(135) => 'C',
        chr(195).chr(136) => 'E', chr(195).chr(137) => 'E',
        chr(195).chr(138) => 'E', chr(195).chr(139) => 'E',
        chr(195).chr(140) => 'I', chr(195).chr(141) => 'I',
        chr(195).chr(142) => 'I', chr(195).chr(143) => 'I',
        chr(195).chr(144) => 'D', chr(195).chr(145) => 'N',
        chr(195).chr(146) => 'O', chr(195).chr(147) => 'O',
        chr(195).chr(148) => 'O', chr(195).chr(149) => 'O',
        chr(195).chr(150) => 'O', chr(195).chr(153) => 'U',
        chr(195).chr(154) => 'U', chr(195).chr(155) => 'U',
        chr(195).chr(156) => 'U', chr(195).chr(157) => 'Y',
        chr(195).chr(158) => 'TH',chr(195).chr(159) => 's',
        chr(195).chr(160) => 'a', chr(195).chr(161) => 'a',
        chr(195).chr(162) => 'a', chr(195).chr(163) => 'a',
        chr(195).chr(164) => 'a', chr(195).chr(165) => 'a',
        chr(195).chr(166) => 'ae',chr(195).chr(167) => 'c',
        chr(195).chr(168) => 'e', chr(195).chr(169) => 'e',
        chr(195).chr(170) => 'e', chr(195).chr(171) => 'e',
        chr(195).chr(172) => 'i', chr(195).chr(173) => 'i',
        chr(195).chr(174) => 'i', chr(195).chr(175) => 'i',
        chr(195).chr(176) => 'd', chr(195).chr(177) => 'n',
        chr(195).chr(178) => 'o', chr(195).chr(179) => 'o',
        chr(195).chr(180) => 'o', chr(195).chr(181) => 'o',
        chr(195).chr(182) => 'o', chr(195).chr(182) => 'o',
        chr(195).chr(185) => 'u', chr(195).chr(186) => 'u',
        chr(195).chr(187) => 'u', chr(195).chr(188) => 'u',
        chr(195).chr(189) => 'y', chr(195).chr(190) => 'th',
        chr(195).chr(191) => 'y',
        // Decompositions for Latin Extended-A
        chr(196).chr(128) => 'A', chr(196).chr(129) => 'a',
        chr(196).chr(130) => 'A', chr(196).chr(131) => 'a',
        chr(196).chr(132) => 'A', chr(196).chr(133) => 'a',
        chr(196).chr(134) => 'C', chr(196).chr(135) => 'c',
        chr(196).chr(136) => 'C', chr(196).chr(137) => 'c',
        chr(196).chr(138) => 'C', chr(196).chr(139) => 'c',
        chr(196).chr(140) => 'C', chr(196).chr(141) => 'c',
        chr(196).chr(142) => 'D', chr(196).chr(143) => 'd',
        chr(196).chr(144) => 'D', chr(196).chr(145) => 'd',
        chr(196).chr(146) => 'E', chr(196).chr(147) => 'e',
        chr(196).chr(148) => 'E', chr(196).chr(149) => 'e',
        chr(196).chr(150) => 'E', chr(196).chr(151) => 'e',
        chr(196).chr(152) => 'E', chr(196).chr(153) => 'e',
        chr(196).chr(154) => 'E', chr(196).chr(155) => 'e',
        chr(196).chr(156) => 'G', chr(196).chr(157) => 'g',
        chr(196).chr(158) => 'G', chr(196).chr(159) => 'g',
        chr(196).chr(160) => 'G', chr(196).chr(161) => 'g',
        chr(196).chr(162) => 'G', chr(196).chr(163) => 'g',
        chr(196).chr(164) => 'H', chr(196).chr(165) => 'h',
        chr(196).chr(166) => 'H', chr(196).chr(167) => 'h',
        chr(196).chr(168) => 'I', chr(196).chr(169) => 'i',
        chr(196).chr(170) => 'I', chr(196).chr(171) => 'i',
        chr(196).chr(172) => 'I', chr(196).chr(173) => 'i',
        chr(196).chr(174) => 'I', chr(196).chr(175) => 'i',
        chr(196).chr(176) => 'I', chr(196).chr(177) => 'i',
        chr(196).chr(178) => 'IJ',chr(196).chr(179) => 'ij',
        chr(196).chr(180) => 'J', chr(196).chr(181) => 'j',
        chr(196).chr(182) => 'K', chr(196).chr(183) => 'k',
        chr(196).chr(184) => 'k', chr(196).chr(185) => 'L',
        chr(196).chr(186) => 'l', chr(196).chr(187) => 'L',
        chr(196).chr(188) => 'l', chr(196).chr(189) => 'L',
        chr(196).chr(190) => 'l', chr(196).chr(191) => 'L',
        chr(197).chr(128) => 'l', chr(197).chr(129) => 'L',
        chr(197).chr(130) => 'l', chr(197).chr(131) => 'N',
        chr(197).chr(132) => 'n', chr(197).chr(133) => 'N',
        chr(197).chr(134) => 'n', chr(197).chr(135) => 'N',
        chr(197).chr(136) => 'n', chr(197).chr(137) => 'N',
        chr(197).chr(138) => 'n', chr(197).chr(139) => 'N',
        chr(197).chr(140) => 'O', chr(197).chr(141) => 'o',
        chr(197).chr(142) => 'O', chr(197).chr(143) => 'o',
        chr(197).chr(144) => 'O', chr(197).chr(145) => 'o',
        chr(197).chr(146) => 'OE',chr(197).chr(147) => 'oe',
        chr(197).chr(148) => 'R',chr(197).chr(149) => 'r',
        chr(197).chr(150) => 'R',chr(197).chr(151) => 'r',
        chr(197).chr(152) => 'R',chr(197).chr(153) => 'r',
        chr(197).chr(154) => 'S',chr(197).chr(155) => 's',
        chr(197).chr(156) => 'S',chr(197).chr(157) => 's',
        chr(197).chr(158) => 'S',chr(197).chr(159) => 's',
        chr(197).chr(160) => 'S', chr(197).chr(161) => 's',
        chr(197).chr(162) => 'T', chr(197).chr(163) => 't',
        chr(197).chr(164) => 'T', chr(197).chr(165) => 't',
        chr(197).chr(166) => 'T', chr(197).chr(167) => 't',
        chr(197).chr(168) => 'U', chr(197).chr(169) => 'u',
        chr(197).chr(170) => 'U', chr(197).chr(171) => 'u',
        chr(197).chr(172) => 'U', chr(197).chr(173) => 'u',
        chr(197).chr(174) => 'U', chr(197).chr(175) => 'u',
        chr(197).chr(176) => 'U', chr(197).chr(177) => 'u',
        chr(197).chr(178) => 'U', chr(197).chr(179) => 'u',
        chr(197).chr(180) => 'W', chr(197).chr(181) => 'w',
        chr(197).chr(182) => 'Y', chr(197).chr(183) => 'y',
        chr(197).chr(184) => 'Y', chr(197).chr(185) => 'Z',
        chr(197).chr(186) => 'z', chr(197).chr(187) => 'Z',
        chr(197).chr(188) => 'z', chr(197).chr(189) => 'Z',
        chr(197).chr(190) => 'z', chr(197).chr(191) => 's',
        // Decompositions for Latin Extended-B
        chr(200).chr(152) => 'S', chr(200).chr(153) => 's',
        chr(200).chr(154) => 'T', chr(200).chr(155) => 't',
        // Euro Sign
        chr(226).chr(130).chr(172) => 'E',
        // GBP (Pound) Sign
        chr(194).chr(163) => '');

        $string = strtr($string, $chars);
    } else {
        // Assume ISO-8859-1 if not UTF-8
        $chars['in'] = chr(128).chr(131).chr(138).chr(142).chr(154).chr(158)
            .chr(159).chr(162).chr(165).chr(181).chr(192).chr(193).chr(194)
            .chr(195).chr(196).chr(197).chr(199).chr(200).chr(201).chr(202)
            .chr(203).chr(204).chr(205).chr(206).chr(207).chr(209).chr(210)
            .chr(211).chr(212).chr(213).chr(214).chr(216).chr(217).chr(218)
            .chr(219).chr(220).chr(221).chr(224).chr(225).chr(226).chr(227)
            .chr(228).chr(229).chr(231).chr(232).chr(233).chr(234).chr(235)
            .chr(236).chr(237).chr(238).chr(239).chr(241).chr(242).chr(243)
            .chr(244).chr(245).chr(246).chr(248).chr(249).chr(250).chr(251)
            .chr(252).chr(253).chr(255);

        $chars['out'] = "EfSZszYcYuAAAAAACEEEEIIIINOOOOOOUUUUYaaaaaaceeeeiiiinoooooouuuuyy";

        $string = strtr($string, $chars['in'], $chars['out']);
        $double_chars['in'] = array(chr(140), chr(156), chr(198), chr(208), chr(222), chr(223), chr(230), chr(240), chr(254));
        $double_chars['out'] = array('OE', 'oe', 'AE', 'DH', 'TH', 'ss', 'ae', 'dh', 'th');
        $string = str_replace($double_chars['in'], $double_chars['out'], $string);
    }

    return $string;
}