Just putting here as an alternative (a bit more complex in nature), wordpress uses this function for accent removal. Made some changes below to make it run indepndently without referencing wordpress functions.
function mbstring_binary_safe_encoding($reset = false)
{
static $encodings = array();
static $overloaded = null;
if (is_null($overloaded)) {
$overloaded = function_exists('mb_internal_encoding') && (ini_get('mbstring.func_overload') & 2);
}
if (false === $overloaded) {
return;
}
if (!$reset) {
$encoding = mb_internal_encoding();
array_push($encodings, $encoding);
mb_internal_encoding('ISO-8859-1');
}
if ($reset && $encodings) {
$encoding = array_pop($encodings);
mb_internal_encoding($encoding);
}
}
function seems_utf8($str)
{
mbstring_binary_safe_encoding();
$length = strlen($str);
mbstring_binary_safe_encoding(true);
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
'ª' => 'a', 'º' => 'o',
'À' => 'A', 'Á' => 'A',
'Â' => 'A', 'Ã' => 'A',
'Ä' => 'A', 'Å' => 'A',
'Æ' => 'AE', 'Ç' => 'C',
'È' => 'E', 'É' => 'E',
'Ê' => 'E', 'Ë' => 'E',
'Ì' => 'I', 'Í' => 'I',
'Î' => 'I', 'Ï' => 'I',
'Ð' => 'D', 'Ñ' => 'N',
'Ò' => 'O', 'Ó' => 'O',
'Ô' => 'O', 'Õ' => 'O',
'Ö' => 'O', 'Ù' => 'U',
'Ú' => 'U', 'Û' => 'U',
'Ü' => 'U', 'Ý' => 'Y',
'Þ' => 'TH', 'ß' => 's',
'à' => 'a', 'á' => 'a',
'â' => 'a', 'ã' => 'a',
'ä' => 'a', 'å' => 'a',
'æ' => 'ae', 'ç' => 'c',
'è' => 'e', 'é' => 'e',
'ê' => 'e', 'ë' => 'e',
'ì' => 'i', 'í' => 'i',
'î' => 'i', 'ï' => 'i',
'ð' => 'd', 'ñ' => 'n',
'ò' => 'o', 'ó' => 'o',
'ô' => 'o', 'õ' => 'o',
'ö' => 'o', 'ø' => 'o',
'ù' => 'u', 'ú' => 'u',
'û' => 'u', 'ü' => 'u',
'ý' => 'y', 'þ' => 'th',
'ÿ' => 'y', 'Ø' => 'O',
// Decompositions for Latin Extended-A
'Ā' => 'A', 'ā' => 'a',
'Ă' => 'A', 'ă' => 'a',
'Ą' => 'A', 'ą' => 'a',
'Ć' => 'C', 'ć' => 'c',
'Ĉ' => 'C', 'ĉ' => 'c',
'Ċ' => 'C', 'ċ' => 'c',
'Č' => 'C', 'č' => 'c',
'Ď' => 'D', 'ď' => 'd',
'Đ' => 'D', 'đ' => 'd',
'Ē' => 'E', 'ē' => 'e',
'Ĕ' => 'E', 'ĕ' => 'e',
'Ė' => 'E', 'ė' => 'e',
'Ę' => 'E', 'ę' => 'e',
'Ě' => 'E', 'ě' => 'e',
'Ĝ' => 'G', 'ĝ' => 'g',
'Ğ' => 'G', 'ğ' => 'g',
'Ġ' => 'G', 'ġ' => 'g',
'Ģ' => 'G', 'ģ' => 'g',
'Ĥ' => 'H', 'ĥ' => 'h',
'Ħ' => 'H', 'ħ' => 'h',
'Ĩ' => 'I', 'ĩ' => 'i',
'Ī' => 'I', 'ī' => 'i',
'Ĭ' => 'I', 'ĭ' => 'i',
'Į' => 'I', 'į' => 'i',
'İ' => 'I', 'ı' => 'i',
'IJ' => 'IJ', 'ij' => 'ij',
'Ĵ' => 'J', 'ĵ' => 'j',
'Ķ' => 'K', 'ķ' => 'k',
'ĸ' => 'k', 'Ĺ' => 'L',
'ĺ' => 'l', 'Ļ' => 'L',
'ļ' => 'l', 'Ľ' => 'L',
'ľ' => 'l', 'Ŀ' => 'L',
'ŀ' => 'l', 'Ł' => 'L',
'ł' => 'l', 'Ń' => 'N',
'ń' => 'n', 'Ņ' => 'N',
'ņ' => 'n', 'Ň' => 'N',
'ň' => 'n', 'ʼn' => 'n',
'Ŋ' => 'N', 'ŋ' => 'n',
'Ō' => 'O', 'ō' => 'o',
'Ŏ' => 'O', 'ŏ' => 'o',
'Ő' => 'O', 'ő' => 'o',
'Œ' => 'OE', 'œ' => 'oe',
'Ŕ' => 'R', 'ŕ' => 'r',
'Ŗ' => 'R', 'ŗ' => 'r',
'Ř' => 'R', 'ř' => 'r',
'Ś' => 'S', 'ś' => 's',
'Ŝ' => 'S', 'ŝ' => 's',
'Ş' => 'S', 'ş' => 's',
'Š' => 'S', 'š' => 's',
'Ţ' => 'T', 'ţ' => 't',
'Ť' => 'T', 'ť' => 't',
'Ŧ' => 'T', 'ŧ' => 't',
'Ũ' => 'U', 'ũ' => 'u',
'Ū' => 'U', 'ū' => 'u',
'Ŭ' => 'U', 'ŭ' => 'u',
'Ů' => 'U', 'ů' => 'u',
'Ű' => 'U', 'ű' => 'u',
'Ų' => 'U', 'ų' => 'u',
'Ŵ' => 'W', 'ŵ' => 'w',
'Ŷ' => 'Y', 'ŷ' => 'y',
'Ÿ' => 'Y', 'Ź' => 'Z',
'ź' => 'z', 'Ż' => 'Z',
'ż' => 'z', 'Ž' => 'Z',
'ž' => 'z', 'ſ' => 's',
// Decompositions for Latin Extended-B
'Ș' => 'S', 'ș' => 's',
'Ț' => 'T', 'ț' => 't',
// Euro Sign
'€' => 'E',
// GBP (Pound) Sign
'£' => '',
// Vowels with diacritic (Vietnamese)
// unmarked
'Ơ' => 'O', 'ơ' => 'o',
'Ư' => 'U', 'ư' => 'u',
// grave accent
'Ầ' => 'A', 'ầ' => 'a',
'Ằ' => 'A', 'ằ' => 'a',
'Ề' => 'E', 'ề' => 'e',
'Ồ' => 'O', 'ồ' => 'o',
'Ờ' => 'O', 'ờ' => 'o',
'Ừ' => 'U', 'ừ' => 'u',
'Ỳ' => 'Y', 'ỳ' => 'y',
// hook
'Ả' => 'A', 'ả' => 'a',
'Ẩ' => 'A', 'ẩ' => 'a',
'Ẳ' => 'A', 'ẳ' => 'a',
'Ẻ' => 'E', 'ẻ' => 'e',
'Ể' => 'E', 'ể' => 'e',
'Ỉ' => 'I', 'ỉ' => 'i',
'Ỏ' => 'O', 'ỏ' => 'o',
'Ổ' => 'O', 'ổ' => 'o',
'Ở' => 'O', 'ở' => 'o',
'Ủ' => 'U', 'ủ' => 'u',
'Ử' => 'U', 'ử' => 'u',
'Ỷ' => 'Y', 'ỷ' => 'y',
// tilde
'Ẫ' => 'A', 'ẫ' => 'a',
'Ẵ' => 'A', 'ẵ' => 'a',
'Ẽ' => 'E', 'ẽ' => 'e',
'Ễ' => 'E', 'ễ' => 'e',
'Ỗ' => 'O', 'ỗ' => 'o',
'Ỡ' => 'O', 'ỡ' => 'o',
'Ữ' => 'U', 'ữ' => 'u',
'Ỹ' => 'Y', 'ỹ' => 'y',
// acute accent
'Ấ' => 'A', 'ấ' => 'a',
'Ắ' => 'A', 'ắ' => 'a',
'Ế' => 'E', 'ế' => 'e',
'Ố' => 'O', 'ố' => 'o',
'Ớ' => 'O', 'ớ' => 'o',
'Ứ' => 'U', 'ứ' => 'u',
// dot below
'Ạ' => 'A', 'ạ' => 'a',
'Ậ' => 'A', 'ậ' => 'a',
'Ặ' => 'A', 'ặ' => 'a',
'Ẹ' => 'E', 'ẹ' => 'e',
'Ệ' => 'E', 'ệ' => 'e',
'Ị' => 'I', 'ị' => 'i',
'Ọ' => 'O', 'ọ' => 'o',
'Ộ' => 'O', 'ộ' => 'o',
'Ợ' => 'O', 'ợ' => 'o',
'Ụ' => 'U', 'ụ' => 'u',
'Ự' => 'U', 'ự' => 'u',
'Ỵ' => 'Y', 'ỵ' => 'y',
// Vowels with diacritic (Chinese, Hanyu Pinyin)
'ɑ' => 'a',
// macron
'Ǖ' => 'U', 'ǖ' => 'u',
// acute accent
'Ǘ' => 'U', 'ǘ' => 'u',
// caron
'Ǎ' => 'A', 'ǎ' => 'a',
'Ǐ' => 'I', 'ǐ' => 'i',
'Ǒ' => 'O', 'ǒ' => 'o',
'Ǔ' => 'U', 'ǔ' => 'u',
'Ǚ' => 'U', 'ǚ' => 'u',
// grave accent
'Ǜ' => 'U', 'ǜ' => 'u',
);
$string = strtr($string, $chars);
} else {
$chars = array();
// Assume ISO-8859-1 if not UTF-8
$chars['in'] = "\x80\x83\x8a\x8e\x9a\x9e"
. "\x9f\xa2\xa5\xb5\xc0\xc1\xc2"
. "\xc3\xc4\xc5\xc7\xc8\xc9\xca"
. "\xcb\xcc\xcd\xce\xcf\xd1\xd2"
. "\xd3\xd4\xd5\xd6\xd8\xd9\xda"
. "\xdb\xdc\xdd\xe0\xe1\xe2\xe3"
. "\xe4\xe5\xe7\xe8\xe9\xea\xeb"
. "\xec\xed\xee\xef\xf1\xf2\xf3"
. "\xf4\xf5\xf6\xf8\xf9\xfa\xfb"
. "\xfc\xfd\xff";
$chars['out'] = "EfSZszYcYuAAAAAACEEEEIIIINOOOOOOUUUUYaaaaaaceeeeiiiinoooooouuuuyy";
$string = strtr($string, $chars['in'], $chars['out']);
$double_chars = array();
$double_chars['in'] = array("\x8c", "\x9c", "\xc6", "\xd0", "\xde", "\xdf", "\xe6", "\xf0", "\xfe");
$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;
}