XML 解析器函数
在线手册：中文 英文
PHP手册

utf8_decode

(PHP 4, PHP 5)

utf8_decode — 将用 UTF-8 方式编码的 ISO-8859-1 字符串转换成单字节的 ISO-8859-1 字符串。

描述

string utf8_decode ( string $data )

该函数将用 UTF-8 编码的数据解码为 ISO-8859-1 编码。

请参阅 utf8_encode() 以查看关于 UTF-8 编码的解释。

XML 解析器函数
在线手册：中文 英文
PHP手册
PHP手册 - N: 将用 UTF-8 方式编码的 ISO-8859-1 字符串转换成单字节的 ISO-8859-1 字符串。

用户评论:

natura2003-4 at yahoo dot it (02-Mar-2012 03:17)

Hi, I'm a newbie.
I've a problem with opencart google product feed.
I get this error in Internet explorer when opening feed.php:
Riferimento all'entità non definita "rsquo"
that in english i think it is this:
Reference to undefined entity "rsquo"
I think it is a problem of italian characters in UTF-8
HOW to solve the problem? Someone indicated me utf-8_decode but I don't know what to do.
can you help me?

loshen at p3 dot ie (01-Mar-2012 11:34)

$trans->mixed_to_utf8 , andrews notes worked for me.

deceze at gmail dot com (15-Jul-2011 03:01)

Please note that utf8_decode simply converts a string encoded in UTF-8 to ISO-8859-1. A more appropriate name for it would be utf8_to_iso88591. If your text is already encoded in ISO-8859-1, you do not need this function. If you don't want to use ISO-8859-1, you do not need this function.

Note that UTF-8 can represent many more characters than ISO-8859-1. Trying to convert a UTF-8 string that contains characters that can't be represented in ISO-8859-1 to ISO-8859-1 will garble your text and/or cause characters to go missing. Trying to convert text that is not encoded in UTF-8 using this function will most likely garble the text.

If you need to convert any text from any encoding to any other encoding, look at iconv() instead.

gabriel arobase gabsoftware dot com (12-Jun-2011 04:41)

If you want to retrieve some UTF-8 data from your database, you don't need utf8_decode().

Simply do the following query before any SELECT :

$result = mysql_query("SET NAMES utf8");

vidthekid at live dot com (19-Oct-2010 03:30)

Got around to some very basic testing of my modified UTF-8 to HTML Entities function.  Apparently preg_replace doesn't like null-characters in its patterns.  That was the only glaring error (actually a warning, but it caused the returned string to be empty) I've encountered.  That's been fixed.  Also, support for four-byte UTF-8 sequences has been added.  Finally, arithmetic operators have been replaced with bitwise operators, which should make the conversion slightly faster and less prone to wild results given invalid input — even though the invalid input should have been filtered out already.

<?PHP
function UTF8ToEntities ($string) {
    /* note: apply htmlspecialchars if desired /before/ applying this function
    /* Only do the slow convert if there are 8-bit characters */
    /* avoid using 0xA0 (\240) in ereg ranges. RH73 does not like that */
    if (! ereg("[\200-\237]", $string) and ! ereg("[\241-\377]", $string))
        return $string;
   
    // reject too-short sequences
    $string = preg_replace("/[\302-\375]([\001-\177])/", "&#65533;\\1", $string);
    $string = preg_replace("/[\340-\375].([\001-\177])/", "&#65533;\\1", $string);
    $string = preg_replace("/[\360-\375]..([\001-\177])/", "&#65533;\\1", $string);
    $string = preg_replace("/[\370-\375]...([\001-\177])/", "&#65533;\\1", $string);
    $string = preg_replace("/[\374-\375]....([\001-\177])/", "&#65533;\\1", $string);
   
    // reject illegal bytes & sequences
        // 2-byte characters in ASCII range
    $string = preg_replace("/[\300-\301]./", "&#65533;", $string);
        // 4-byte illegal codepoints (RFC 3629)
    $string = preg_replace("/\364[\220-\277]../", "&#65533;", $string);
        // 4-byte illegal codepoints (RFC 3629)
    $string = preg_replace("/[\365-\367].../", "&#65533;", $string);
        // 5-byte illegal codepoints (RFC 3629)
    $string = preg_replace("/[\370-\373]..../", "&#65533;", $string);
        // 6-byte illegal codepoints (RFC 3629)
    $string = preg_replace("/[\374-\375]...../", "&#65533;", $string);
        // undefined bytes
    $string = preg_replace("/[\376-\377]/", "&#65533;", $string);

    // reject consecutive start-bytes
    $string = preg_replace("/[\302-\364]{2,}/", "&#65533;", $string);
   
    // decode four byte unicode characters
    $string = preg_replace(
        "/([\360-\364])([\200-\277])([\200-\277])([\200-\277])/e",
        "'&#'.((ord('\\1')&7)<<18 | (ord('\\2')&63)<<12 |" .
        " (ord('\\3')&63)<<6 | (ord('\\4')&63)).';'",
    $string);
   
    // decode three byte unicode characters
    $string = preg_replace("/([\340-\357])([\200-\277])([\200-\277])/e",
"'&#'.((ord('\\1')&15)<<12 | (ord('\\2')&63)<<6 | (ord('\\3')&63)).';'",
    $string);
   
    // decode two byte unicode characters
    $string = preg_replace("/([\300-\337])([\200-\277])/e",
    "'&#'.((ord('\\1')&31)<<6 | (ord('\\2')&63)).';'",
    $string);
   
    // reject leftover continuation bytes
    $string = preg_replace("/[\200-\277]/", "&#65533;", $string);
   
    return $string;
}
?>

Warning: only a bit of accidental testing was done with invalid UTF-8 input, and the result wasn't closely analyzed.  But valid UTF-8 doesn't seem to be mangled at all.

mkluczka at gmail dot com (16-Sep-2010 12:36)

In jQuery AJAX requests, latin2 specific chars have 2B length, and common chars have 1B length.

PHP functions for UTF8->latin2 conversion didn't work for me, so I wrote this simple function
to convert from jQuery AJAX encoding to ISO-8859-2 (latin2).

<?php
function jquery2iso($in)
{
  $CONV = array();
  $CONV['c4']['85'] = '?';
  $CONV['c4']['84'] = '?';
  $CONV['c4']['87'] = '?';
  $CONV['c4']['86'] = '?';
  $CONV['c4']['99'] = '?';
  $CONV['c4']['98'] = '?';
  $CONV['c5']['82'] = '?';
  $CONV['c5']['81'] = '?';
  $CONV['c4']['84'] = 'ń';
  $CONV['c4']['83'] = '?';
  $CONV['c3']['b3'] = 'ó';
  $CONV['c3']['93'] = '?';
  $CONV['c5']['9b'] = '?';
  $CONV['c5']['9a'] = '?';
  $CONV['c5']['ba'] = '?';
  $CONV['c5']['b9'] = '?';
  $CONV['c5']['bc'] = '?';
  $CONV['c5']['bb'] = '?';

  $i=0;
  $out = '';
  while($i<strlen($in))
  {
    if(array_key_exists(bin2hex($in[$i]), $CONV))
    {
      $out .= $CONV[bin2hex($in[$i])][bin2hex($in[$i+1])];
      $i += 2;
    }
    else
    {
      $out .= $in[$i];
      $i += 1;
    }
  }

  return $out;
}

?>

andrew (25-Nov-2009 04:13)

a simple function to convert encoding that appears mixed.

<?php
$trans = new Latin1UTF8();

$mixed = "MIXED TEXT INPUT";

print "Original: ".$mixed;
print "Latin1:   ".$trans->mixed_to_latin1($mixed);
print "UTF-8:    ".$trans->mixed_to_utf8($mixed);

class Latin1UTF8 {
   
    private $latin1_to_utf8;
    private $utf8_to_latin1;
    public function __construct() {
        for($i=32; $i<=255; $i++) {
            $this->latin1_to_utf8[chr($i)] = utf8_encode(chr($i));
            $this->utf8_to_latin1[utf8_encode(chr($i))] = chr($i);
        }
    }
   
    public function mixed_to_latin1($text) {
        foreach( $this->utf8_to_latin1 as $key => $val ) {
            $text = str_replace($key, $val, $text);
        }
        return $text;
    }

    public function mixed_to_utf8($text) {
        return utf8_encode($this->mixed_to_latin1($text));
    }
}
?>

Anonymous (08-Aug-2009 10:25)

In addition to Blackbit's note below, here's my shot at converting UTF-8 strings to HTML entities.

<?php $encoded = preg_replace('/([\200-\277])/e', "'&#'.(ord('\\1')).';'", $utf8str); ?>

This code converts one byte UTF-8 to HTML entities while below you'll find conversions for two byte and three byte UTF-8.

Johan K (27-Jul-2009 03:53)

If you simply need to decode a previously numerically escaped string (for example "This is \xC3encoded\xAF - now what?") into its literal (unencoded) representation:

<?php
preg_replace("#(\\\x[0-9A-F]{2})#e", "chr(hexdec('\\1'))", $string);
?>

PS: note the miraculous escaping of \x in the regex as \\\x (!)

pedro at pontonet dot com (05-May-2009 11:25)

I've modified above utf8_array_decode to utf8_array_encode. The main difference is the later encodes a multi-dimension array.

Here goes the code:

<?php
function utf8_array_encode($input)
{
    $return = array();

    foreach ($input as $key => $val)
    {
        if( is_array($val) )
        {
            $return[$key] = utf8_array_encode($val);
        }
        else
        {
            $return[$key] = utf8_encode($val);
        }
    }
    return $return;          
}
?>

Enjoy it!

Pedro Bastos

ytak at gmx dot net (30-Jan-2009 05:35)

If you running Gentoo Linux and encounter problems with some PHP5 applications saying:
Call to undefined function: utf8_decode()
Try reemerge PHP4 with 'xml' flag enabled.

info at vanylla dot it (26-Jan-2009 08:21)

IMPORTANT: when converting UTF8 data that contains the EURO sign DON'T USE utf_decode function.

utf_decode converts the data into ISO-8859-1 charset. But ISO-8859-1 charset does not contain the EURO sign, therefor the EURO sign will be converted into a question mark character '?'

In order to convert properly UTF8 data with EURO sign you must use:

iconv("UTF-8", "CP1252", $data)

Blackbit (12-Aug-2008 12:40)

Squirrelmail contains a nice function in the sources to convert unicode to entities:

<?php
function charset_decode_utf_8 ($string) {
      /* Only do the slow convert if there are 8-bit characters */
    /* avoid using 0xA0 (\240) in ereg ranges. RH73 does not like that */
    if (! ereg("[\200-\237]", $string) and ! ereg("[\241-\377]", $string))
        return $string;

    // decode three byte unicode characters
    $string = preg_replace("/([\340-\357])([\200-\277])([\200-\277])/e",        \
    "'&#'.((ord('\\1')-224)*4096 + (ord('\\2')-128)*64 + (ord('\\3')-128)).';'",    \
    $string);

    // decode two byte unicode characters
    $string = preg_replace("/([\300-\337])([\200-\277])/e", \
    "'&#'.((ord('\\1')-192)*64+(ord('\\2')-128)).';'", \
    $string);

    return $string;
}
?>

punchivan at gmail dot com (24-Jun-2008 10:13)

EY! the bug is not in the function 'utf8_decode'. The bug is in the function 'mb_detect_encoding'. If you put a word with a special char at the end like this 'accentué', that will lead to a wrong result (UTF-8) but if you put another char at the end like this 'accentuée' you will get it right. So you should always add a ISO-8859-1 character to your string for this check. My advise is to use a blank space.
I?ve tried it and it works!

function ISO_convert($array)
{
    $array_temp = array();
    
    foreach($array as $name => $value)
    {
        if(is_array($value))
          $array_temp[(mb_detect_encoding($name." ",'UTF-8,ISO-8859-1') == 'UTF-8' ? utf8_decode($name) : $name )] = ISO_convert($value);
        else
          $array_temp[(mb_detect_encoding($name." ",'UTF-8,ISO-8859-1') == 'UTF-8' ? utf8_decode($name) : $name )] = (mb_detect_encoding($value." ",'UTF-8,ISO-8859-1') == 'UTF-8' ? utf8_decode($value) : $value );
    }

    return $array_temp;
}

webmaster at lapstore dot de (19-Jun-2008 04:11)

[EDITED BY cataphract AT php DOT net - NOTE: This has been fixed
in PHP 5.3.4 and 5.2.15.]

Warning!
This function contains a possible security risk when you try to convert escaped strings (see addslashes() and related functions).
It reacts nasty on broken multibyte sequences. In UTF-8, follow-up bytes ALWAYS have the binary pattern 10xxxxxx, but this fact is not handled by utf8_decode in the way you would expect: If you pass a start byte (110xxxxx, 1110xxxx, 11110xxx - or even invalid sequences like 11111100), followed by one or more non-multibyte chars (0xxxxxxx), the start sequence "char" will be replaced by '?' (0x3F) and up to three following chars will disappear even if they are single-byte-chars (0xxxxxxx). So if you escape a string with a typical escape char like backslash, you would expect that your escaping would always survive a call to utf8decode because the escape char is in the assumed safe ascii range 0-127, but that is NOT the case!
Try things like utf8_decode("test: ü\\\"123456") to check it out.
To avoid problems take care that string-escaping always is the last step of data manipulation when you depend on leak-proof escaping.

juantxito at example dot com (28-May-2008 09:26)

To decode the values and the keys, i think this would work

 function utf8_array_decode($input){

    $return = array();

        foreach ($input as $key => $val) {
        $k = utf8_decode($key);
                $return[$k] = utf8_decode($val);
            }
            return $return;          
        }

phpnet at freshsite dot de (09-May-2008 09:08)

I didn't find an utf8_array_decode. This one only decodes the values, not the keys.

        function utf8_array_decode($input){
            foreach ($input as $key => $val) {
                $input[$key] = utf8_decode($val);
            }
            return $input;           
        }

haugas at gmail dot com (08-May-2008 10:11)

If you don't know exactly, how many times your string is encoded, you can use this function:

<?php

function _utf8_decode($string)
{
  $tmp = $string;
  $count = 0;
  while (mb_detect_encoding($tmp)=="UTF-8")
  {
    $tmp = utf8_decode($tmp);
    $count++;
  }
 
  for ($i = 0; $i < $count-1 ; $i++)
  {
    $string = utf8_decode($string);
   
  }
  return $string;
 
}

?>

lukasz dot mlodzik at gmail dot com (05-Mar-2008 12:46)

Update to MARC13 function utf2iso()
I'm using it to handle AJAX POST calls.
Despite using
http.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded'; charset='utf-8');
it still code Polish letters using UTF-16

This is only for Polish letters:
 
<?php
function utf16_2_utf8 ($nowytekst) {
        $nowytekst = str_replace('%u0104','?',$nowytekst);    //?
        $nowytekst = str_replace('%u0106','?',$nowytekst);    //?
        $nowytekst = str_replace('%u0118','?',$nowytekst);    //?
        $nowytekst = str_replace('%u0141','?',$nowytekst);    //?
        $nowytekst = str_replace('%u0143','?',$nowytekst);    //?
        $nowytekst = str_replace('%u00D3','?',$nowytekst);    //?
        $nowytekst = str_replace('%u015A','?',$nowytekst);    //?
        $nowytekst = str_replace('%u0179','?',$nowytekst);    //?
        $nowytekst = str_replace('%u017B','?',$nowytekst);    //?
      
        $nowytekst = str_replace('%u0105','?',$nowytekst);    //?
        $nowytekst = str_replace('%u0107','?',$nowytekst);    //?
        $nowytekst = str_replace('%u0119','?',$nowytekst);    //?
        $nowytekst = str_replace('%u0142','?',$nowytekst);    //?
        $nowytekst = str_replace('%u0144','ń',$nowytekst);    //ń
        $nowytekst = str_replace('%u00F3','ó',$nowytekst);    //ó
        $nowytekst = str_replace('%u015B','?',$nowytekst);    //?
        $nowytekst = str_replace('%u017A','?',$nowytekst);    //?
        $nowytekst = str_replace('%u017C','?',$nowytekst);    //?
   return ($nowytekst);
   }   
?>

Everything goes smooth, but it doesn't change '%u00D3','?' and '%u00F3','ó'. I dont have idea what to do with that.

Remember! File must be saved in UTF-8 coding.

tacchete at gmail dot com (13-Dec-2007 12:36)

Known problem with Byte Order Mark (BOM) and header() in pages of a site.

For example at sending headings or to a dynamic conclusion in other coding distinct from UTF-8 by means of XSLT (<xsl:output encoding="windows-1251"/>).

To clean all symbols BOM from the text of page:

1. exclude BOM from the main file;
2. write down function of a return call for the buffer

<?php
header('content-type: text/html; charset: utf-8');
ob_start('ob');
function ob($buffer)
{
    return str_replace("\xef\xbb\xbf", '', $buffer);
}
?>

it will exclude BOM from a code of the connected files;
3. do not experience for BOM in connected files;
4. be pleased.

ludvig dot ericson at gmail dot com (15-Jul-2007 06:52)

A better way to convert would be to use iconv, see http://www.php.net/iconv -- example:

<?php
$myUnicodeString = "???";
echo iconv("UTF-8", "ISO-8859-1", $myUnicodeString);
?>

Above would echo out the given variable in ISO-8859-1 encoding, you may replace it with whatever you prefer.

Another solution to the issue of misdisplayed glyphs is to simply send the document as UTF-8, and of course send UTF-8 data:

<?php
# Replace text/html with whatever MIME-type you prefer.
header("Content-Type: text/html; charset=utf-8");
?>

MARC13 (07-Jul-2007 03:50)

I did this function to convert data from AJAX call to insert to my database.
It converts UTF-8 from XMLHttpRequest() to ISO-8859-2 that I use in LATIN2 MySQL database.

<?php
function utf2iso($tekst)
{
        $nowytekst = str_replace("%u0104","\xA1",$tekst);    //?
        $nowytekst = str_replace("%u0106","\xC6",$nowytekst);    //?
        $nowytekst = str_replace("%u0118","\xCA",$nowytekst);    //?
        $nowytekst = str_replace("%u0141","\xA3",$nowytekst);    //?
        $nowytekst = str_replace("%u0143","\xD1",$nowytekst);    //?
        $nowytekst = str_replace("%u00D3","\xD3",$nowytekst);    //?
        $nowytekst = str_replace("%u015A","\xA6",$nowytekst);    //?
        $nowytekst = str_replace("%u0179","\xAC",$nowytekst);    //?
        $nowytekst = str_replace("%u017B","\xAF",$nowytekst);    //?
       
        $nowytekst = str_replace("%u0105","\xB1",$nowytekst);    //?
        $nowytekst = str_replace("%u0107","\xE6",$nowytekst);    //?
        $nowytekst = str_replace("%u0119","\xEA",$nowytekst);    //?
        $nowytekst = str_replace("%u0142","\xB3",$nowytekst);    //?
        $nowytekst = str_replace("%u0144","\xF1",$nowytekst);    //ń
        $nowytekst = str_replace("%u00D4","\xF3",$nowytekst);    //ó
        $nowytekst = str_replace("%u015B","\xB6",$nowytekst);    //?
        $nowytekst = str_replace("%u017A","\xBC",$nowytekst);    //?
        $nowytekst = str_replace("%u017C","\xBF",$nowytekst);    //?
       
    return ($nowytekst);
}
?>

In my case also the code file that deals with AJAX calls must be in UTF-8 coding.

visus at portsonline dot net (23-Jun-2007 05:08)

Following code helped me with mixed (UTF8+ISO-8859-1(x)) encodings. In this case, I have template files made and maintained by designers who do not care about encoding and MySQL data in utf8_binary_ci encoded tables.

<?php

class Helper
{
    function strSplit($text, $split = 1)
    {
        if (!is_string($text)) return false;
        if (!is_numeric($split) && $split < 1) return false;

        $len = strlen($text);

        $array = array();

        $i = 0;

        while ($i < $len)
        {
            $key = NULL;

            for ($j = 0; $j < $split; $j += 1)
            {
                $key .= $text{$i};

                $i += 1;
            }

            $array[] = $key;
        }

        return $array;
    }

    function UTF8ToHTML($str)
    {
        $search = array();
        $search[] = "/([\\xC0-\\xF7]{1,1}[\\x80-\\xBF]+)/e";
        $search[] = "/&#228;/";
        $search[] = "/&#246;/";
        $search[] = "/&#252;/";
        $search[] = "/&#196;/";
        $search[] = "/&#214;/";
        $search[] = "/&#220;/";
        $search[] = "/&#223;/";

        $replace = array();
        $replace[] = 'Helper::_UTF8ToHTML("\\1")';
        $replace[] = "?";
        $replace[] = "?";
        $replace[] = "ü";
        $replace[] = "?";
        $replace[] = "?";
        $replace[] = "ü";
        $replace[] = "?";

        $str = preg_replace($search, $replace, $str);

        return $str;
    }

    function _UTF8ToHTML($str)
    {
        $ret = 0;

        foreach((Helper::strSplit(strrev(chr((ord($str{0}) % 252 % 248 % 240 % 224 % 192) + 128).substr($str, 1)))) as $k => $v)
            $ret += (ord($v) % 128) * pow(64, $k);
        return "&#".$ret.";";
    }
}

// Usage example:

$tpl = file_get_contents("template.tpl");
/* ... */
$row = mysql_fetch_assoc($result);

print(Helper::UTF8ToHTML(str_replace("{VAR}", $row['var'], $tpl)));

?>

luka8088 at gmail dot com (22-Jun-2007 03:03)

simple UTF-8 to HTML conversion:

function utf8_to_html ($data)
    {
    return preg_replace("/([\\xC0-\\xF7]{1,1}[\\x80-\\xBF]+)/e", '_utf8_to_html("\\1")', $data);
    }

function _utf8_to_html ($data)
    {
    $ret = 0;
    foreach((str_split(strrev(chr((ord($data{0}) % 252 % 248 % 240 % 224 % 192) + 128) . substr($data, 1)))) as $k => $v)
        $ret += (ord($v) % 128) * pow(64, $k);
    return "&#$ret;";
    }

Example:
echo utf8_to_html("a b ? ? ? こ に ち わ ()[]{}!#$?*");

Output:
a b &#269; &#263; &#382; &#12371; &#12395; &#12385; &#12431; ()[]{}!#$?*

Sadi (13-Jun-2007 11:38)

Once again about polish letters. If you use fananf's solution, make sure that PHP file is coded with cp1250 or else it won't work. It's quite obvious, however I spent some time before I finally figured that out, so I thought I post it here.

alexlevin at kvadro dot net (21-May-2007 04:20)

If you running Gentoo Linux and encounter problems with some PHP4 applications saying:
Call to undefined function: utf8_decode()
Try reemerge PHP4 with 'expat' flag enabled.

ahmed dot adaileh at gmail dot com (08-Mar-2007 11:32)

I searched a lot everywhere to find a suitable function which converts my UTF8 characters to the windows-1250 charset for Polish language, but couldn't find anything :(

Following is a function which does that:

function show_polish ($text) {
 $text = str_replace("??", '&#260;', $text); //?
 $text = str_replace("??", '&#262;', $text); //?
 $text = str_replace("??", '&#280;', $text); //?
 $text = str_replace("??", '&#321;', $text); //?
 $text = str_replace("??", '&#323;', $text); //?
 $text = str_replace("?“", '&#211;', $text); //?
 $text = str_replace("??", '&#346;', $text); //?
 $text = str_replace("??", '&#377;', $text); //?
 $text = str_replace("??", '&#379;', $text); //?
 $text = str_replace("?…", '&#261;', $text); //?
 $text = str_replace("??", '&#263;', $text); //?
 $text = str_replace("??", '&#281;', $text); //?
 $text = str_replace("??", '&#322;', $text); //?
 $text = str_replace("??", '&#324;', $text); //ń
 $text = str_replace("??", '&#243;', $text); //ó
 $text = str_replace("??", '&#347;', $text); //?
 $text = str_replace("??", '&#378;', $text); //?
 $text = str_replace("??", '&#380;', $text); //?
 
return $text;
}

You can refer to http://hermes.umcs.lublin.pl/~awmarcz/awm/info/pl-codes.htm
if you want to use HTML hex. code rather than HTML dec. code which I used in my function.

fananf at nerdshack dot com (05-Mar-2007 03:22)

Comment to AJGORS reply from 28-Dec-2006 02:38:

You have used twice "?" instead of "?".

Correct code should be:

ISO version:

function utf82iso88592($text) {
 $text = str_replace("\xC4\x85", '±', $text);
 $text = str_replace("\xC4\x84", 'ˇ', $text);
 $text = str_replace("\xC4\x87", '?', $text);
 $text = str_replace("\xC4\x86", '?', $text);
 $text = str_replace("\xC4\x99", '?', $text);
 $text = str_replace("\xC4\x98", '?', $text);
 $text = str_replace("\xC5\x82", '?', $text);
 $text = str_replace("\xC5\x81", '?', $text);
 $text = str_replace("\xC3\xB3", 'ó', $text);
 $text = str_replace("\xC3\x93", '?', $text);
 $text = str_replace("\xC5\x9B", '?', $text);
 $text = str_replace("\xC5\x9A", '?', $text);
 $text = str_replace("\xC5\xBC", '?', $text);
 $text = str_replace("\xC5\xBB", '?', $text);
 $text = str_replace("\xC5\xBA", '?', $text);
 $text = str_replace("\xC5\xB9", '?', $text);
 $text = str_replace("\xc5\x84", 'ń', $text);
 $text = str_replace("\xc5\x83", '?', $text);

return $text;
}

CP version:

function utf82iso88592($text) {
 $text = str_replace("\xC4\x85", '?', $text);
 $text = str_replace("\xC4\x84", '?', $text);
 $text = str_replace("\xC4\x87", '?', $text);
 $text = str_replace("\xC4\x86", '?', $text);
 $text = str_replace("\xC4\x99", '?', $text);
 $text = str_replace("\xC4\x98", '?', $text);
 $text = str_replace("\xC5\x82", '?', $text);
 $text = str_replace("\xC5\x81", '?', $text);
 $text = str_replace("\xC3\xB3", 'ó', $text);
 $text = str_replace("\xC3\x93", '?', $text);
 $text = str_replace("\xC5\x9B", '?', $text);
 $text = str_replace("\xC5\x9A", '?', $text);
 $text = str_replace("\xC5\xBC", '?', $text);
 $text = str_replace("\xC5\xBB", '?', $text);
 $text = str_replace("\xC5\xBA", '?', $text);
 $text = str_replace("\xC5\xB9", '?', $text);
 $text = str_replace("\xc5\x84", 'ń', $text);
 $text = str_replace("\xc5\x83", '?', $text);

return $text;
}

sam (06-Feb-2007 04:20)

In addition to yannikh's note, to convert a hex utf8 string

<?php

echo utf8_decode("\x61\xc3\xb6\x61");
// works as expected

$abc="61c3b661";
$newstr = "";
$l = strlen($abc);
for ($i=0;$i<$l;$i+=2){
    $newstr .= "\x".$abc[$i].$abc[$i+1];
}
echo utf8_decode($newstr);
// or varieties  of "\x": "\\x" etc does NOT output what you want

echo utf8_decode(pack('H*',$abc));
// this outputs the correct string, like the first line.

?>

Ajgor (28-Dec-2006 01:38)

small upgrade for polish decoding:

function utf82iso88592($text) {
 $text = str_replace("\xC4\x85", '?', $text);
 $text = str_replace("\xC4\x84", '?', $text);
 $text = str_replace("\xC4\x87", '?', $text);
 $text = str_replace("\xC4\x86", '?', $text);
 $text = str_replace("\xC4\x99", '?', $text);
 $text = str_replace("\xC4\x98", '?', $text);
 $text = str_replace("\xC5\x82", '?', $text);
 $text = str_replace("\xC5\x81", '?', $text);
 $text = str_replace("\xC3\xB3", 'ó', $text);
 $text = str_replace("\xC3\x93", '?', $text);
 $text = str_replace("\xC5\x9B", '?', $text);
 $text = str_replace("\xC5\x9A", '?', $text);
 $text = str_replace("\xC5\xBC", '?', $text);
 $text = str_replace("\xC5\xBB", '?', $text);
 $text = str_replace("\xC5\xBA", '?', $text);
 $text = str_replace("\xC5\xB9", '?', $text);
 $text = str_replace("\xc5\x84", 'ń', $text);
 $text = str_replace("\xc5\x83", '?', $text);

return $text;
} // utf82iso88592

paul.hayes at entropedia.co.uk (27-Oct-2006 03:10)

I noticed that the utf-8 to html functions below are only for 2 byte long codes. Well I wanted 3 byte support (sorry haven't done 4, 5 or 6). Also I noticed the concatination of the character codes did have the hex prefix 0x and so failed with the large 2 byte codes)

<?
  public function utf2html (&$str) {
   
    $ret = "";
    $max = strlen($str);
    $last = 0;  // keeps the index of the last regular character
    for ($i=0; $i<$max; $i++) {
        $c = $str{$i};
        $c1 = ord($c);
        if ($c1>>5 == 6) {  // 110x xxxx, 110 prefix for 2 bytes unicode
            $ret .= substr($str, $last, $i-$last); // append all the regular characters we've passed
            $c1 &= 31; // remove the 3 bit two bytes prefix
            $c2 = ord($str{++$i}); // the next byte
            $c2 &= 63;  // remove the 2 bit trailing byte prefix
            $c2 |= (($c1 & 3) << 6); // last 2 bits of c1 become first 2 of c2
            $c1 >>= 2; // c1 shifts 2 to the right
            $ret .= "&#" . ($c1 * 0x100 + $c2) . ";"; // this is the fastest string concatenation
            $last = $i+1;      
        }
        elseif ($c1>>4 == 14) {  // 1110 xxxx, 110 prefix for 3 bytes unicode
            $ret .= substr($str, $last, $i-$last); // append all the regular characters we've passed
            $c2 = ord($str{++$i}); // the next byte
            $c3 = ord($str{++$i}); // the third byte
            $c1 &= 15; // remove the 4 bit three bytes prefix
            $c2 &= 63;  // remove the 2 bit trailing byte prefix
            $c3 &= 63;  // remove the 2 bit trailing byte prefix
            $c3 |= (($c2 & 3) << 6); // last 2 bits of c2 become first 2 of c3
            $c2 >>=2; //c2 shifts 2 to the right
            $c2 |= (($c1 & 15) << 4); // last 4 bits of c1 become first 4 of c2
            $c1 >>= 4; // c1 shifts 4 to the right
            $ret .= '&#' . (($c1 * 0x10000) + ($c2 * 0x100) + $c3) . ';'; // this is the fastest string concatenation
            $last = $i+1;      
        }
    }
    $str=$ret . substr($str, $last, $i); // append the last batch of regular characters
}
?>

tobias at code-x dot de (20-Oct-2006 01:13)

converting uft8-html sign &#301; to uft8

<?
function uft8html2utf8( $s ) {
        if ( !function_exists('uft8html2utf8_callback') ) {
             function uft8html2utf8_callback($t) {
                     $dec = $t[1];
            if ($dec < 128) {
              $utf = chr($dec);
            } else if ($dec < 2048) {
              $utf = chr(192 + (($dec - ($dec % 64)) / 64));
              $utf .= chr(128 + ($dec % 64));
            } else {
              $utf = chr(224 + (($dec - ($dec % 4096)) / 4096));
              $utf .= chr(128 + ((($dec % 4096) - ($dec % 64)) / 64));
              $utf .= chr(128 + ($dec % 64));
            }
            return $utf;
             }
        }                               
        return preg_replace_callback('|&#([0-9]{1,});|', 'uft8html2utf8_callback', $s );                                
}
echo uft8html2utf8('test: &#301;');
?>

e dot panzyk at panzyk dot net (04-Oct-2006 10:38)

enhanced UTF8-Decoder

After recognising that UTF8-Decode converts some French Characters to "?" i end with that Function.

The space will be need when a String ends with a converted Char ( a buggy Php Function will fit a /hex00 char at the End )

function utf8dec ( $s_String )
    {
    $s_String = html_entity_decode(htmlentities($s_String." ", ENT_COMPAT, 'UTF-8'));
    return substr($s_String, 0, strlen($s_String)-1);
    }

Hope it helps ... cost me a lot of time ...

michael at calwell-computing dot co dot uk (04-Oct-2006 09:15)

I found that trying to put Javascript strings into a pre MySQL 4.0 database was creating problems with strange chars in the database. Closer inspection revealed that utf8 is the default character set for Javascript, which cannot be handled by the db. This function was invaluable.

ethaizone [AT] hotmail [DOT] com (02-Aug-2006 06:11)

This function I use convert UTF-8 to Thai font (iso-8859-11).
It from iso8859_11toUTF8 function [Suttichai Mesaard-www.ceforce.com] at utf8_encode page.

It useful for translate string from mod_rewrite to real url.
I makes SEO Url In Thai language.

<?php
function UTF8toiso8859_11($string) {
 
     if ( ! ereg("[\241-\377]", $string) )
         return $string;
 
     $UTF8 = array(
"\xe0\xb8\x81" => "\xa1",
"\xe0\xb8\x82" => "\xa2",
"\xe0\xb8\x83" => "\xa3",
"\xe0\xb8\x84" => "\xa4",
"\xe0\xb8\x85" => "\xa5",
"\xe0\xb8\x86" => "\xa6",
"\xe0\xb8\x87" => "\xa7",
"\xe0\xb8\x88" => "\xa8",
"\xe0\xb8\x89" => "\xa9",
"\xe0\xb8\x8a" => "\xaa",
"\xe0\xb8\x8b" => "\xab",
"\xe0\xb8\x8c" => "\xac",
"\xe0\xb8\x8d" => "\xad",
"\xe0\xb8\x8e" => "\xae",
"\xe0\xb8\x8f" => "\xaf",
"\xe0\xb8\x90" => "\xb0",
"\xe0\xb8\x91" => "\xb1",
"\xe0\xb8\x92" => "\xb2",
"\xe0\xb8\x93" => "\xb3",
"\xe0\xb8\x94" => "\xb4",
"\xe0\xb8\x95" => "\xb5",
"\xe0\xb8\x96" => "\xb6",
"\xe0\xb8\x97" => "\xb7",
"\xe0\xb8\x98" => "\xb8",
"\xe0\xb8\x99" => "\xb9",
"\xe0\xb8\x9a" => "\xba",
"\xe0\xb8\x9b" => "\xbb",
"\xe0\xb8\x9c" => "\xbc",
"\xe0\xb8\x9d" => "\xbd",
"\xe0\xb8\x9e" => "\xbe",
"\xe0\xb8\x9f" => "\xbf",
"\xe0\xb8\xa0" => "\xc0",
"\xe0\xb8\xa1" => "\xc1",
"\xe0\xb8\xa2" => "\xc2",
"\xe0\xb8\xa3" => "\xc3",
"\xe0\xb8\xa4" => "\xc4",
"\xe0\xb8\xa5" => "\xc5",
"\xe0\xb8\xa6" => "\xc6",
"\xe0\xb8\xa7" => "\xc7",
"\xe0\xb8\xa8" => "\xc8",
"\xe0\xb8\xa9" => "\xc9",
"\xe0\xb8\xaa" => "\xca",
"\xe0\xb8\xab" => "\xcb",
"\xe0\xb8\xac" => "\xcc",
"\xe0\xb8\xad" => "\xcd",
"\xe0\xb8\xae" => "\xce",
"\xe0\xb8\xaf" => "\xcf",
"\xe0\xb8\xb0" => "\xd0",
"\xe0\xb8\xb1" => "\xd1",
"\xe0\xb8\xb2" => "\xd2",
"\xe0\xb8\xb3" => "\xd3",
"\xe0\xb8\xb4" => "\xd4",
"\xe0\xb8\xb5" => "\xd5",
"\xe0\xb8\xb6" => "\xd6",
"\xe0\xb8\xb7" => "\xd7",
"\xe0\xb8\xb8" => "\xd8",
"\xe0\xb8\xb9" => "\xd9",
"\xe0\xb8\xba" => "\xda",
"\xe0\xb8\xbf" => "\xdf",
"\xe0\xb9\x80" => "\xe0",
"\xe0\xb9\x81" => "\xe1",
"\xe0\xb9\x82" => "\xe2",
"\xe0\xb9\x83" => "\xe3",
"\xe0\xb9\x84" => "\xe4",
"\xe0\xb9\x85" => "\xe5",
"\xe0\xb9\x86" => "\xe6",
"\xe0\xb9\x87" => "\xe7",
"\xe0\xb9\x88" => "\xe8",
"\xe0\xb9\x89" => "\xe9",
"\xe0\xb9\x8a" => "\xea",
"\xe0\xb9\x8b" => "\xeb",
"\xe0\xb9\x8c" => "\xec",
"\xe0\xb9\x8d" => "\xed",
"\xe0\xb9\x8e" => "\xee",
"\xe0\xb9\x8f" => "\xef",
"\xe0\xb9\x90" => "\xf0",
"\xe0\xb9\x91" => "\xf1",
"\xe0\xb9\x92" => "\xf2",
"\xe0\xb9\x93" => "\xf3",
"\xe0\xb9\x94" => "\xf4",
"\xe0\xb9\x95" => "\xf5",
"\xe0\xb9\x96" => "\xf6",
"\xe0\xb9\x97" => "\xf7",
"\xe0\xb9\x98" => "\xf8",
"\xe0\xb9\x99" => "\xf9",
"\xe0\xb9\x9a" => "\xfa",
"\xe0\xb9\x9b" => "\xfb",
 );
 
     $string=strtr($string,$UTF8);
     return $string;
 }
?>

Jo, EThaiZone.Com

2ge at NO2geSPAM dot us (26-Jan-2006 09:00)

Hello all,

I like to use COOL (nice) URIs, example: http://example.com/try-something
I'm using UTF8 as input, so I have to write a function UTF8toASCII to have nice URI. Here is what I come with:

<?php
function urlize($url) {
 $search = array('/[^a-z0-9]/', '/--+/', '/^-+/', '/-+$/' );
 $replace = array( '-', '-', '', '');
 return preg_replace($search, $replace, utf2ascii($url));
}    

function utf2ascii($string) {
 $iso88591  = "\\xE0\\xE1\\xE2\\xE3\\xE4\\xE5\\xE6\\xE7";
 $iso88591 .= "\\xE8\\xE9\\xEA\\xEB\\xEC\\xED\\xEE\\xEF";
 $iso88591 .= "\\xF0\\xF1\\xF2\\xF3\\xF4\\xF5\\xF6\\xF7";
 $iso88591 .= "\\xF8\\xF9\\xFA\\xFB\\xFC\\xFD\\xFE\\xFF";
 $ascii = "aaaaaaaceeeeiiiidnooooooouuuuyyy";
 return strtr(mb_strtolower(utf8_decode($string), 'ISO-8859-1'),$iso88591,$ascii);
}

echo urlize("Fucking ml");

?>

I hope this helps someone.

peter dot mescalchin at geemail dot com (27-Dec-2005 05:43)

Adding to below I have a few more MS word characters that need replacing. Found this was required when "fixing" some phpmyadmin export scripts from a live server where MS word characters were all through the content - before importing them back into my local mySQL database.

The code I wrote for this process also does a strpos for any extra "\\xe2\\x80" strings - which are the tell-tale sign of any funny characters I want removed.

Here are my updated arrays()

<?php
$badchr = array(
    "\\xe2\\x80\\xa6",        // ellipsis
    "\\xe2\\x80\\x93",        // long dash
    "\\xe2\\x80\\x94",        // long dash
    "\\xe2\\x80\\x98",        // single quote opening
    "\\xe2\\x80\\x99",        // single quote closing
    "\\xe2\\x80\\x9c",        // double quote opening
    "\\xe2\\x80\\x9d",        // double quote closing
    "\\xe2\\x80\\xa2"        // dot used for bullet points
    );

$goodchr = array(
    '...',
    '-',
    '-',
    '\\'',
    '\\'',
    '"',
    '"',
    '*'
    );
?>

php-net at ---NOSPAM---lc dot yi dot org (08-Dec-2005 08:04)

I've just created this code snippet to improve the user-customizable emails sent by one of my websites.

The goal was to use UTF-8 (Unicode) so that non-english users have all the Unicode benefits, BUT also make life seamless for English (or specifically, English MS-Outlook users).  The niggle: Outlook prior to 2003 (?)  does not properly detect unicode emails.  When "smart quotes" from MS Word were pasted into a rich text area and saved in Unicode, then sent by email to an Outlook user, more often than not, these characters were wrongly rendered as "greek".

So, the following code snippet replaces a few strategic characters into html entities which Outlook XP (and possibly earlier) will render as expected.  [Code based on bits of code from previous posts on this and the htmlenties page]
<?php
    $badwordchars=array(
        "\xe2\x80\x98", // left single quote
        "\xe2\x80\x99", // right single quote
        "\xe2\x80\x9c", // left double quote
        "\xe2\x80\x9d", // right double quote
        "\xe2\x80\x94", // em dash
        "\xe2\x80\xa6" // elipses
    );
    $fixedwordchars=array(
        "&#8216;",
        "&#8217;",
        '&#8220;',
        '&#8221;',
        '&mdash;',
        '&#8230;'
    );
    $html=str_replace($badwordchars,$fixedwordchars,$html);
?>

yannikh at gmeil dot com (08-Dec-2005 07:34)

I had to tackle a very interesting problem:

I wanted to replace all \xXX in a text by it's letters. Unfortunatelly XX were ASCII and not utf8. I solved my problem that way:
<?php preg_replace ('/\\\\x([0-9a-fA-F]{2})/e', "pack('H*',utf8_decode('\\1'))",$v); ?>

thierry.bo # netcourrier point com (01-Oct-2005 08:53)

to complete my previous test, here is the summarize with :

- if ($string == utf8_decode($string))
- if ($string == iconv('UTF-8', 'UTF-8', $string)

201 lines are valid UTF8 strings using phpnote regexp
203 lines are valid UTF8 strings using j.dittmer regexp
200 lines are valid UTF8 strings using fhoech regexp
239 lines are valid  UTF8 strings using using mb_detect_encoding
203 lines are valid  UTF 8 strings using using utf8_decode
224 lines are valid  UTF 8strings using using iconv

If we trust the file used for this test, no need to use a regexp, use XML::utf8_decode() to test your strings, you get the same detection chance as the three regexp tested, and XML Parser extension is almost always available, unlike Iconv and Multibyte String functions.

thierry.bo # netcourrier point com (30-Sep-2005 08:38)

In response to fhoech (22-Sep-2005 11:55), I just tried a simultaneous test with the file UTF-8-test.txt using your regexp, 'j dot dittmer' (20-Sep-2005 06:30) regexp (message #56962), `php-note-2005` (17-Feb-2005 08:57) regexp in his message on `mb-detect-encoding` page (http://us3.php.net/manual/en/function.mb-detect-encoding.php#50087) who is using a regexp from the W3C (http://w3.org/International/questions/qa-forms-utf-8.html), and PHP mb_detect_encoding function.

Here are a summarize of the results :

201 lines are valid UTF8 strings using phpnote regexp
203 lines are valid UTF8 strings using j.dittmer regexp
200 lines are valid UTF8 strings using fhoech regexp
239 lines are valid  UTF8 strings using using mb_detect_encoding

Here are the lines with differences (left to right, phpnote, j.dittmer and fhoech) :

Line #70 : NOT UTF8|IS UTF8!|IS UTF8! :2.1.1 1 byte (U-00000000): ""
Line #79 : NOT UTF8|IS UTF8!|IS UTF8! :2.2.1 1 byte (U-0000007F): ""
Line #81 : IS UTF8!|IS UTF8!|NOT UTF8 :2.2.3 3 bytes (U-0000FFFF): "&#65535;" |
Line #267 : IS UTF8!|IS UTF8!|NOT UTF8 :5.3.1 U+FFFE = ef bf be = "&#65534;" |
Line #268 : IS UTF8!|IS UTF8!|NOT UTF8 :5.3.2 U+FFFF = ef bf bf = "&#65535;" |

Interesting is that you said that your regexp corrected j.dittmer regexp that failed on 5.3 section, but it my test I have the opposite result ?!

I ran this test on windows XP with PHP 4.3.11dev. Maybe these differences come from operating system, or PHP version.

For mb_detect_encoding I used the command :

mb_detect_encoding($line, 'UTF-8, ISO-8859-1, ASCII');

fhoech (22-Sep-2005 06:55)

Sorry, I had a typo in my last comment. Corrected regexp:

^([\\x00-\\x7f]|
[\\xc2-\\xdf][\\x80-\\xbf]|
\\xe0[\\xa0-\\xbf][\\x80-\\xbf]|
[\\xe1-\\xec][\\x80-\\xbf]{2}|
\\xed[\\x80-\\x9f][\\x80-\\xbf]|
\\xef[\\x80-\\xbf][\\x80-\\xbd]|
\\xee[\\x80-\\xbf]{2}|
\xf0[\\x90-\\xbf][\\x80-\\xbf]{2}|
[\\xf1-\\xf3][\\x80-\\xbf]{3}|
\\xf4[\\x80-\\x8f][\\x80-\\xbf]{2})*$

fhoech (22-Sep-2005 06:12)

JF Sebastian's regex is almost perfect as far as I'm concerned. I found one error (it failed section 5.3 "Other illegal code positions" from http://www.cl.cam.ac.uk/~mgk25/ucs/examples/UTF-8-test.txt) which I corrected as follows:

^([\\x00-\\x7f]|
[\\xc2-\\xdf][\\x80-\\xbf]|
\\xe0[\\xa0-\\xbf][\\x80-\\xbf]|
[\\xe1-\\xec][\\x80-\\xbf]{2}|
\\xed[\\x80-\\x9f][\\x80-\\xbf]|
\\xef[\\x80-\\xbf][\\x80-\\xbc]|
\\xee[\\x80-\\xbf]{2}|
\\xf0[\\x90-\\xbf][\\x80-\\xbf]{2}|
[\\xf1-\\xf3][\\x80-\\xbf]{3}|
\\xf4[\\x80-\\x8f][\\x80-\\xbf]{2})*$

(Again, concatenate to one single line to make it work)

j dot dittmer at portrix dot net (20-Sep-2005 01:30)

The regex in the last comment has some typos. This is a
syntactically valid one, don't know if it's correct though.
You've to concat the expression in one long line.

^(
[\x00-\x7f]|
[\xc2-\xdf][\x80-\xbf]|
[\xe0][\xa0-\xbf][\x80-\xbf]|
[\xe1-\xec][\x80-\xbf]{2}|
[\xed][\x80-\x9f][\x80-\xbf]|
[\xee-\xef][\x80-\xbf]{2}|
[\xf0][\x90-\xbf][\x80-\xbf]{2}|
[\xf1-\xf3][\x80-\xbf]{3}|
[\xf4][\x80-\x8f][\x80-\xbf]{2}
)*$

chris at mrwsp dot com (09-Aug-2005 11:54)

A small improvement.

JF Sebastian's regex for UTF-8 is not quite correct.  Because code points could otherwise be coded in more than one way using UTF-8, the Standard stipulates that the shortest possible representation for a character should be used.  So some 'duplicate' combinations his regex accepts are not valid UTF-8.  Additionally, his regex accepts characters beyond the valid Unicode code space.

The regex should be:

^([\x00-\x7f]|
[\xc2-\xdf][\x80-\xbf]|
[\xe0][\xa0-\xbf][\x80-xbf]|
[\xe1-\xec][\x80-\xbf]{2}|
[\xed][\x80-\x9f][\x80-\xbf]|
[\xee-\xef][\x80-\xbf]{2}|
[\xf0][\x90-\xbf][\x80-\xbf]{2}|
[\xf1-\xf3][\x80-\xbf]{3}|
[\xf4][\x80-\x8f][\x80-\xbf]{2}*$)

miracle at balkansys dot com (14-Jun-2005 10:24)

The best multilanguage library I have found is a part of a CMS system - typo3

http://www.typo3.org

It can convert from and to any charset + it does it by three methods - mbstring, iconv, or the raw way by scripts. It uses only one of these techniques - the fastest if available.

That was the only way I could make mysql 3.23 contain letters in almost any language, while maintaining my website in utf-8 only.

Vladimir Stwora, vlad4321 at fastmail dot fm (08-May-2005 11:41)

If you want to convert utf-8 to ascii, you can use the following procedure:

<?php
function utf2ascii($string) {
   $string=iconv('utf-8','windows-1250',$string);
   $win  ='...';  // I was unable to paste here all set of characters, but you get the point
   $ascii='zyaieuu...';
   $string = StrTr($string,$win,$ascii);
   return $string;
  }
?>
This works based on the assumption that you know what language text (and thus what charset) you want to convert from. In the above example I am converting from an eastern European language, so I know I can safely use windows-1250 charset as an intermediem charset. You will have to adjust the charset based on your language.

Please remember that you have to save this file separately and it must be coded in the charset, which you will call within function iconv. Otherwise it will not work.

JF Sebastian (30-Mar-2005 03:09)

The following Perl regular expression tests if a string is well-formed Unicode UTF-8 (Broken up after each | since long lines are not permitted here. Please join as a single line, no spaces, before use.):

^([\x00-\x7f]|
[\xc2-\xdf][\x80-\xbf]|
\xe0[\xa0-\xbf][\x80-\xbf]|
[\xe1-\xec][\x80-\xbf]{2}|
\xed[\x80-\x9f][\x80-\xbf]|
[\xee-\xef][\x80-\xbf]{2}|
f0[\x90-\xbf][\x80-\xbf]{2}|
[\xf1-\xf3][\x80-\xbf]{3}|
\xf4[\x80-\x8f][\x80-\xbf]{2})*$

NOTE: This strictly follows the Unicode standard 4.0, as described in chapter 3.9, table 3-6, "Well-formed UTF-8 byte sequences" ( http://www.unicode.org/versions/Unicode4.0.0/ch03.pdf#G31703 ).

ISO-10646, a super-set of Unicode, uses UTF-8 (there called "UCS", see http://www.unicode.org/faq/utf_bom.html#1 ) in a relaxed variant that supports a 31-bit space encoded into up to six bytes instead of Unicode's 21 bits in up to four bytes. To check for ISO-10646 UTF-8, use the following Perl regular expression (again, broken up, see above):

^([\x00-\x7f]|
[\xc0-\xdf][\x80-\xbf]|
[\xe0-\xef][\x80-\xbf]{2}|
[\xf0-\xf7][\x80-\xbf]{3}|
[\xf8-\xfb][\x80-\xbf]{4}|
[\xfc-\xfd][\x80-\xbf]{5})*$

The following function may be used with above expressions for a quick UTF-8 test, e.g. to distinguish ISO-8859-1-data from UTF-8-data if submitted from a <form accept-charset="utf-8,iso-8859-1" method=..>.

function is_utf8($string) {
    return (preg_match('/[insert regular expression here]/', $string) === 1);
}

ivanmaz(remove) at mech dot math dot msu dot su (15-Mar-2005 11:50)

Here is my variant of UTF8 to Cyrillic Win-1251 encoding convertor that replaces all characters but latin and Russian ones with &#...; entities:

function utf2win1251 ($s)
{
 $out = "";

 for ($i=0; $i<strlen($s); $i++)
 {
  $c1 = substr ($s, $i, 1);
  $byte1 = ord ($c1);
  if ($byte1>>5 == 6) // 110x xxxx, 110 prefix for 2 bytes unicode
  {
   $i++;
   $c2 = substr ($s, $i, 1);
   $byte2 = ord ($c2);
   $byte1 &= 31; // remove the 3 bit two bytes prefix
   $byte2 &= 63; // remove the 2 bit trailing byte prefix
   $byte2 |= (($byte1 & 3) << 6); // last 2 bits of c1 become first 2 of c2
   $byte1 >>= 2; // c1 shifts 2 to the right

   $word = ($byte1<<8) + $byte2;
   if ($word==1025) $out .= chr(168);                    //
   elseif ($word==1105) $out .= chr(184);                //
   elseif ($word>=0x0410 && $word<=0x044F) $out .= chr($word-848); // - -
   else
   { 
     $a = dechex($byte1);
     $a = str_pad($a, 2, "0", STR_PAD_LEFT);
     $b = dechex($byte2);
     $b = str_pad($b, 2, "0", STR_PAD_LEFT);
     $out .= "&#x".$a.$b.";";
   }
  }
  else
  {
   $out .= $c1;
  }
 }

 return $out;
}

The function is based on 2 other functions posted below.
I hope it will help those who convert UTF8-encoded text to Win-1251 to use it safely on Russian web pages (works fine in all browsers).

marcelo at maccoy dot com dot br (14-Feb-2005 06:24)

function decode_utf8($str){
       # erase null signs in string
          $str=eregi_replace("^.{10,13}q\?","",$str);
       # paterns
           $pat = "/=([0-9A-F]{2})/";
           $cha="'.chr(hexdec(";
       # to decode with eval and replace
          eval("\$str='".
                  preg_replace($pat,$cha."'$1')).'",$str).
                  "';");
        # return
           return $str;
        }

Note:
It's possible put it in 3 lines, but I don't got in this first code submition.

husamb at maksimum dot net (27-Jan-2005 09:16)

Hi, I collected the some scripts in this page and I written a new customizable script. You can switch easily iso type to convert. There are definitions in unicode.org page at http://www.unicode.org/Public/MAPPINGS/ISO8859/.

<?php
# GLOBAL VARIABLES
$url = "http://www.unicode.org/Public/MAPPINGS/ISO8859/8859-9.TXT";
//$url = "8859-9.txt";
$iso2utf = array();
$utf2iso = array();

# UNICODE MAPPING TABLE PARSING
function create_map($url){
    global $iso2utf, $utf2iso;
    $fl = @(file($url)) OR (die("cannot open file : $url\n"));
    for ($i=0; $i<count($fl); $i++){
        if($fl[$i][0] != '#' && trim($fl[$i])){
            list($iso, $uni, $s, $desc) = split("\t",$fl[$i]);
            $iso2utf[$iso] = $uni;
            $utf2iso[$uni] = $iso;
        }
    }
}

# FINDING UNICODE LETTER'S DECIMAL ASCII VALUE
function uniord($c){
    $ud = 0;
    if (ord($c{0})>=0 && ord($c{0})<=127)   $ud = $c{0};
    if (ord($c{0})>=192 && ord($c{0})<=223) $ud = (ord($c{0})-192)*64 + (ord($c{1})-128);
    if (ord($c{0})>=224 && ord($c{0})<=239) $ud = (ord($c{0})-224)*4096 + (ord($c{1})-128)*64 + (ord($c{2})-128);
    if (ord($c{0})>=240 && ord($c{0})<=247) $ud = (ord($c{0})-240)*262144 + (ord($c{1})-128)*4096 + (ord($c{2})-128)*64 + (ord($c{3})-128);
    if (ord($c{0})>=248 && ord($c{0})<=251) $ud = (ord($c{0})-248)*16777216 + (ord($c{1})-128)*262144 + (ord($c{2})-128)*4096 + (ord($c{3})-128)*64 + (ord($c{4})-128);
    if (ord($c{0})>=252 && ord($c{0})<=253) $ud = (ord($c{0})-252)*1073741824 + (ord($c{1})-128)*16777216 + (ord($c{2})-128)*262144 + (ord($c{3})-128)*4096 + (ord($c{4})-128)*64 + (ord($c{5})-128);
    if (ord($c{0})>=254 && ord($c{0})<=255) $ud = false; //error
    return $ud;
}

# PARSING UNICODE STRING
function utf2iso($source) {
    global $utf2iso;
    $pos = 0;
    $len = strlen ($source);
    $encodedString = '';
   
    while ($pos < $len) {
        $is_ascii = false;
        $asciiPos = ord (substr ($source, $pos, 1));
        if(($asciiPos >= 240) && ($asciiPos <= 255)) {
            // 4 chars representing one unicode character
            $thisLetter = substr ($source, $pos, 4);
            $thisLetterOrd = uniord($thisLetter);
            $pos += 4;
        }
        else if(($asciiPos >= 224) && ($asciiPos <= 239)) {
            // 3 chars representing one unicode character
            $thisLetter = substr ($source, $pos, 3);
            $thisLetterOrd = uniord($thisLetter);
            $pos += 3;
        }
        else if(($asciiPos >= 192) && ($asciiPos <= 223)) {
            // 2 chars representing one unicode character
            $thisLetter = substr ($source, $pos, 2);
            $thisLetterOrd = uniord($thisLetter);
            $pos += 2;
        }
        else{
            // 1 char (lower ascii)
            $thisLetter = substr ($source, $pos, 1);
            $thisLetterOrd = uniord($thisLetter);
            $pos += 1;
            $encodedString .= $thisLetterOrd;
            $is_ascii = true;
        }
        if(!$is_ascii){
            $hex = sprintf("%X", $thisLetterOrd);
            if(strlen($hex)<4) for($t=strlen($hex);$t<4;$t++)$hex = "0".$hex;
            $hex = "0x".$hex;
            $hex = $utf2iso[$hex];
            $hex = str_replace('0x','',$hex);
            $dec = hexdec($hex);
            $encodedString .= sprintf("%c", $dec);
        }
    }
    return $encodedString;
}

# CREATING ISO2UTF & UTF2ISO MAPS
create_map($url);

# TESTING
$unicode_string = "Ekonomi_ve_\xc4\xb0\xc5\x9f_D\xc3\xbcnyas\xc4\xb1";

echo "unicode string : <b>" . $unicode_string . "</b>";
echo "<br><br>";
echo "ISO8859 (latin5 / turkish) converted string : <b>" . utf2iso($unicode_string) . "</b>";
?>

The unicode string is turkish. ITs mean in english is 'Economy and Business World' :)

Husam

rasmus at flajm dot se (19-Jan-2005 10:57)

If you don't have the multibyte extension installed, here's a function to decode UTF-16 encoded strings. It support both BOM-less and BOM'ed strings, (big- and little-endian byte order.)

<?php
/**
 * Decode UTF-16 encoded strings.
 *
 * Can handle both BOM'ed data and un-BOM'ed data.
 * Assumes Big-Endian byte order if no BOM is available.
 *
 * @param   string  $str  UTF-16 encoded data to decode.
 * @return  string  UTF-8 / ISO encoded data.
 * @access  public
 * @version 0.1 / 2005-01-19
 * @author  Rasmus Andersson {@link http://rasmusandersson.se/}
 * @package Groupies
 */
function utf16_decode( $str ) {
    if( strlen($str) < 2 ) return $str;
    $bom_be = true;
    $c0 = ord($str{0});
    $c1 = ord($str{1});
    if( $c0 == 0xfe && $c1 == 0xff ) { $str = substr($str,2); }
    elseif( $c0 == 0xff && $c1 == 0xfe ) { $str = substr($str,2); $bom_be = false; }
    $len = strlen($str);
    $newstr = '';
    for($i=0;$i<$len;$i+=2) {
        if( $bom_be ) { $val = ord($str{$i})   << 4; $val += ord($str{$i+1}); }
        else {        $val = ord($str{$i+1}) << 4; $val += ord($str{$i}); }
        $newstr .= ($val == 0x228) ? "\n" : chr($val);
    }
    return $newstr;
}
?>

dobersch at gmx dot net (04-Nov-2004 02:11)

Sorry, there's an error in my previous comment, my error_reporting was not set to E_ALL ... so the notices disappeared...

It seems that those Google URLs are not only UTF-8 encoded, but after encoding, several values also get replaced. (cp1252 ?)

Just the way as described in following comments on the utf8_encode() page:
http://de3.php.net/manual/de/function.utf8-encode.php#44843 and
http://de3.php.net/manual/de/function.utf8-encode.php#45226

Below I post a solution for getting back the ISO-8859-1 encoded string from the encoded data, by turning the function from Aidan the other way around.

hope this time, everything is alright...

<?PHP
ini_set('error_reporting', E_ALL);
// map taken from http://de3.php.net/manual/de/function.utf8-encode.php#45226
$cp1252_map = array(
   "\xc2\x80" => "\xe2\x82\xac", /* EURO SIGN */
   "\xc2\x82" => "\xe2\x80\x9a", /* SINGLE LOW-9 QUOTATION MARK */
   "\xc2\x83" => "\xc6\x92",    /* LATIN SMALL LETTER F WITH HOOK */
   "\xc2\x84" => "\xe2\x80\x9e", /* DOUBLE LOW-9 QUOTATION MARK */
   "\xc2\x85" => "\xe2\x80\xa6", /* HORIZONTAL ELLIPSIS */
   "\xc2\x86" => "\xe2\x80\xa0", /* DAGGER */
   "\xc2\x87" => "\xe2\x80\xa1", /* DOUBLE DAGGER */
   "\xc2\x88" => "\xcb\x86",    /* MODIFIER LETTER CIRCUMFLEX ACCENT */
   "\xc2\x89" => "\xe2\x80\xb0", /* PER MILLE SIGN */
   "\xc2\x8a" => "\xc5\xa0",    /* LATIN CAPITAL LETTER S WITH CARON */
   "\xc2\x8b" => "\xe2\x80\xb9", /* SINGLE LEFT-POINTING ANGLE QUOTATION */
   "\xc2\x8c" => "\xc5\x92",    /* LATIN CAPITAL LIGATURE OE */
   "\xc2\x8e" => "\xc5\xbd",    /* LATIN CAPITAL LETTER Z WITH CARON */
   "\xc2\x91" => "\xe2\x80\x98", /* LEFT SINGLE QUOTATION MARK */
   "\xc2\x92" => "\xe2\x80\x99", /* RIGHT SINGLE QUOTATION MARK */
   "\xc2\x93" => "\xe2\x80\x9c", /* LEFT DOUBLE QUOTATION MARK */
   "\xc2\x94" => "\xe2\x80\x9d", /* RIGHT DOUBLE QUOTATION MARK */
   "\xc2\x95" => "\xe2\x80\xa2", /* BULLET */
   "\xc2\x96" => "\xe2\x80\x93", /* EN DASH */
   "\xc2\x97" => "\xe2\x80\x94", /* EM DASH */

   "\xc2\x98" => "\xcb\x9c",    /* SMALL TILDE */
   "\xc2\x99" => "\xe2\x84\xa2", /* TRADE MARK SIGN */
   "\xc2\x9a" => "\xc5\xa1",    /* LATIN SMALL LETTER S WITH CARON */
   "\xc2\x9b" => "\xe2\x80\xba", /* SINGLE RIGHT-POINTING ANGLE QUOTATION*/
   "\xc2\x9c" => "\xc5\x93",    /* LATIN SMALL LIGATURE OE */
   "\xc2\x9e" => "\xc5\xbe",    /* LATIN SMALL LETTER Z WITH CARON */
   "\xc2\x9f" => "\xc5\xb8"      /* LATIN CAPITAL LETTER Y WITH DIAERESIS*/
);

// I find this name a little misleading because the result won't be valid UTF8 data
function cp1252_to_utf8($str) {
   global $cp1252_map;
   return  strtr(utf8_encode($str), $cp1252_map);
}

function cp1252_utf8_to_iso($str) { // the other way around...
  global $cp1252_map;
  return  utf8_decode( strtr($str, array_flip($cp1252_map)) );
}

$euro = "\xe2\x82\xac";  // "google encoded" euro sign
$str = cp1252_utf8_to_iso($euro);

for($i=0; $i<strlen($str); $i++) {
  print '&quot;' . $str[$i] . '&quot; - ' . ord($str[$i]) . ' (decimal)<br />';
}
?>

vpribish at shopping dot com (10-Sep-2004 07:55)

big thanks to wielspm and mittag for the function to convert wide utf to html.  I have altered your function to output decimal html entities which i hear are more widely supported.  Also I've optimized it, it is now twice as fast.

<?php
function utf2html ($str) {
$ret = "";
$max = strlen($str);
$last = 0;  // keeps the index of the last regular character
for ($i=0; $i<$max; $i++) {
 $c = $str{$i};
 $c1 = ord($c);
 if ($c1>>5 == 6) {   // 110x xxxx, 110 prefix for 2 bytes unicode
    $ret .= substr($str, $last, $i-$last); // append all the regular characters we've passed
    $c1 &= 31; // remove the 3 bit two bytes prefix
    $c2 = ord($str{++$i}); // the next byte
    $c2 &= 63;  // remove the 2 bit trailing byte prefix
    $c2 |= (($c1 & 3) << 6); // last 2 bits of c1 become first 2 of c2
    $c1 >>= 2; // c1 shifts 2 to the right
    $ret .= "&#" . ($c1 * 100 + $c2) . ";"; // this is the fastest string concatenation
    $last = $i+1;        
 }
}
return $ret . substr($str, $last, $i); // append the last batch of regular characters
}
?>

Aidan Kehoe <php-manual at parhasard dot net> (31-Jan-2004 01:35)

The fastest way I've found to check if something is valid UTF-8 is
<?php
if (iconv('UTF-8', 'UTF-8', $input) != $input) {
        /* It's not UTF-8--for me, it's probably CP1252, the Windows
           version of Latin 1, with directed quotation marks and
           the Euro sign.  */
}
 ?>.
The iconv() C library fails if it's told a string is UTF-8 and it isn't; the PHP one doesn't, it just returns the conversion up to the point of failure, so you have to compare the result to the input to find out if the conversion succeeded.

lg83news at free dot fr (29-Dec-2003 05:40)

Here are some functions for converting UTF-8 to and from Latin 9 (aka ISO-8859-15), if your PHP file is encoded as UTF-8.

<?php
function latin9_to_utf8($latin9str) { // replaces utf8_encode()
    $trans = array(""=>"", ""=>"", ""=>"", ""=>"", ""=>"", ""=>"", ""=>"", ""=>"");
    $wrong_utf8str = utf8_encode($latin9str);
    $utf8str = strtr($wrong_utf8str, $trans);
    return $utf8str;
}
function utf8_to_latin9($utf8str) { // replaces utf8_decode()
    $trans = array(""=>"", ""=>"", ""=>"", ""=>"", ""=>"", ""=>"", ""=>"", ""=>"");
    $wrong_utf8str = strtr($utf8str, $trans);
    $latin9str = utf8_decode($wrong_utf8str);
    return $latin9str;
}
?>

Note: the above functions will not work if your PHP file is not encoded in UTF-8.

You can copy this binary data to your PHP file instead, it'll work with any encoding (including UTF-8) as long as you copy it as bytes, not characters:

<?php
function latin9_to_utf8($latin9str) { // replaces utf8_encode()
    $trans = array("¤"=>"€", "?"=>" ", "¨"=>"?", "?"=>"?", "?"=>"?", "?"=>"?", "?"=>"?", "?"=>"?");
    $wrong_utf8str = utf8_encode($latin9str);
    $utf8str = strtr($wrong_utf8str, $trans);
    return $utf8str;
}
function utf8_to_latin9($utf8str) { // replaces utf8_decode()
    $trans = array("€"=>"¤", " "=>"?", "?"=>"¨", "?"=>"?", "?"=>"?", "?"=>"?", "?"=>"?", "?"=>"?");
    $wrong_utf8str = strtr($utf8str, $trans);
    $latin9str = utf8_decode($wrong_utf8str);
    return $latin9str;
}
?>

(Note: the PHP manual is served as ISO-8859-1, but many of the bytes used here have no meaning in ISO-8859-1, so they'll probably be displayed as Windows-1252 if your using Windows, or garbage otherwise. Just copy the bytes!)

gto at interia dot pl (25-Nov-2003 03:12)

Correction to function converting utf82iso88592 and iso88592tutf8.
Janusz forgot about "&#324;", and "&#380;" exchanged from "&#378;" here and there.

GTo

function utf82iso88592($tekscik) {
     $tekscik = str_replace("\xC4\x85", "&#261;", $tekscik);
     $tekscik = str_replace("\xC4\x84", '&#260;', $tekscik);
     $tekscik = str_replace("\xC4\x87", '&#263;', $tekscik);
     $tekscik = str_replace("\xC4\x86", '&#262;', $tekscik);
     $tekscik = str_replace("\xC4\x99", '&#281;', $tekscik);
     $tekscik = str_replace("\xC4\x98", '&#280;', $tekscik);
     $tekscik = str_replace("\xC5\x82", '&#322;', $tekscik);
     $tekscik = str_replace("\xC5\x81", '&#321;', $tekscik);
     $tekscik = str_replace("\xC5\x84", '&#324;', $tekscik);    
     $tekscik = str_replace("\xC5\x83", '&#323;', $tekscik);
     $tekscik = str_replace("\xC3\xB3", '', $tekscik);
     $tekscik = str_replace("\xC3\x93", '', $tekscik);
     $tekscik = str_replace("\xC5\x9B", '&#347;', $tekscik);
     $tekscik = str_replace("\xC5\x9A", '&#346;', $tekscik);
     $tekscik = str_replace("\xC5\xBC", '&#380;', $tekscik);
     $tekscik = str_replace("\xC5\xBB", '&#379;', $tekscik);
     $tekscik = str_replace("\xC5\xBA", '&#378;', $tekscik);
     $tekscik = str_replace("\xC5\xB9", '&#377;', $tekscik);
     return $tekscik;
} // utf82iso88592

function iso885922utf8($tekscik) {
     $tekscik = str_replace("&#261;", "\xC4\x85", $tekscik);
     $tekscik = str_replace('&#260;', "\xC4\x84", $tekscik);
     $tekscik = str_replace('&#263;', "\xC4\x87", $tekscik);
     $tekscik = str_replace('&#262;', "\xC4\x86", $tekscik);
     $tekscik = str_replace('&#281;', "\xC4\x99", $tekscik);
     $tekscik = str_replace('&#280;', "\xC4\x98", $tekscik);
     $tekscik = str_replace('&#322;', "\xC5\x82", $tekscik);
     $tekscik = str_replace('&#321;', "\xC5\x81", $tekscik);
     $tekscik = str_replace('&#324;', "\xC5\x84", $tekscik);
     $tekscik = str_replace('&#323;',"\xC5\x83", $tekscik);
     $tekscik = str_replace('', "\xC3\xB3", $tekscik);
     $tekscik = str_replace('', "\xC3\x93", $tekscik);
     $tekscik = str_replace('&#347;', "\xC5\x9B", $tekscik);
     $tekscik = str_replace('&#346;', "\xC5\x9A", $tekscik);
     $tekscik = str_replace('&#380;', "\xC5\xBC", $tekscik);
     $tekscik = str_replace('&#379;', "\xC5\xBB", $tekscik);
     $tekscik = str_replace('&#378;', "\xC5\xBA", $tekscik);
     $tekscik = str_replace('&#377;', "\xC5\xB9", $tekscik);    
     return $tekscik;
} // iso885922utf8

nospam at jra dot nu (23-Nov-2003 11:48)

There is an error in the 'smart_utf8_decode' function posted by ' goran_johansson' below. It should look like this:

function smart_utf8_decode($in_str)
{
    // Replace ? with a unique string
    $new_str = str_replace("?", "q0u0e0s0t0i0o0n", $in_str);

    // Try the utf8_decode
    $new_str=utf8_decode($new_str);

    // if it contains ? marks
    if (strpos($new_str,"?") !== false)
    {
        // Something went wrong, set new_str to the original string.
        $new_str=$in_str;
    }
    else
    {
        // If not then all is well, put the ?-marks back where is belongs
        $new_str = str_replace("q0u0e0s0t0i0o0n", "?", $new_str);
    }

    return $new_str;
}

janusz dot s at remove_this dot and_this dot poczta dot fm (25-Oct-2003 04:54)

Here are functions to PROPERLY de/encode Unicode (UTF-8) string to/from ISO-8859-2 (Polish character set).

Regards,
Janusz

function utf82iso88592($tekscik) {
 $tekscik = str_replace("\xC4\x85", "", $tekscik);
 $tekscik = str_replace("\xC4\x84", '', $tekscik);
 $tekscik = str_replace("\xC4\x87", '', $tekscik);
 $tekscik = str_replace("\xC4\x86", '', $tekscik);
 $tekscik = str_replace("\xC4\x99", '', $tekscik);
 $tekscik = str_replace("\xC4\x98", '', $tekscik);
 $tekscik = str_replace("\xC5\x82", '', $tekscik);
 $tekscik = str_replace("\xC5\x81", '', $tekscik);
 $tekscik = str_replace("\xC3\xB3", '', $tekscik);
 $tekscik = str_replace("\xC3\x93", '', $tekscik);
 $tekscik = str_replace("\xC5\x9B", '', $tekscik);
 $tekscik = str_replace("\xC5\x9A", '', $tekscik);
 $tekscik = str_replace("\xC5\xBC", '', $tekscik);
 $tekscik = str_replace("\xC5\xBB", '', $tekscik);
 $tekscik = str_replace("\xC5\xBA", '', $tekscik);
 $tekscik = str_replace("\xC5\xB9", '', $tekscik);
 return $tekscik;
} // utf82iso88592

function iso885922utf8($tekscik) {
 $tekscik = str_replace("", "\xC4\x85", $tekscik);
 $tekscik = str_replace('', "\xC4\x84", $tekscik);
 $tekscik = str_replace('', "\xC4\x87", $tekscik);
 $tekscik = str_replace('', "\xC4\x86", $tekscik);
 $tekscik = str_replace('', "\xC4\x99", $tekscik);
 $tekscik = str_replace('', "\xC4\x98", $tekscik);
 $tekscik = str_replace('', "\xC5\x82", $tekscik);
 $tekscik = str_replace('', "\xC5\x81", $tekscik);
 $tekscik = str_replace('', "\xC3\xB3", $tekscik);
 $tekscik = str_replace('', "\xC3\x93", $tekscik);
 $tekscik = str_replace('', "\xC5\x9B", $tekscik);
 $tekscik = str_replace('', "\xC5\x9A", $tekscik);
 $tekscik = str_replace('', "\xC5\xBC", $tekscik);
 $tekscik = str_replace('', "\xC5\xBB", $tekscik);
 $tekscik = str_replace('', "\xC5\xBA", $tekscik);
 $tekscik = str_replace('', "\xC5\xB9", $tekscik);
 return $tekscik;
} // iso885922utf8

bn2 (bn2 at ukr dot net) (01-Sep-2003 04:56)

Function to decode uft8 to win-1251 (russian) charset. Don't support ukrainian letters. Support only 2-byte coding.

function utf8win1251($s){
$out="";$c1="";$byte2=false;
for ($c=0;$c<strlen($s);$c++){
$i=ord($s[$c]);
if ($i<=127) $out.=$s[$c];
if ($byte2){
$new_c2=($c1&3)*64+($i&63);
$new_c1=($c1>>2)&5;
$new_i=$new_c1*256+$new_c2;
if ($new_i==1025) $out_i=168; else
if ($new_i==1105) $out_i=184; else $out_i=$new_i-848;
$out.=chr($out_i);
$byte2=false;}
if (($i>>5)==6) {$c1=$i;$byte2=true;}
}
return $out;}

morris_hirsch at hotmail dot com (18-Aug-2003 05:43)

Be aware that utf8_decode can not properly store ''wide'' code entities which have a numeric value too big for a byte.

This function may help you.  It converts utf8 to strict ASCII with no high-bit codes, they are all written as numerics.

// UTF-8 encoding
// bytes bits representation
// 1   7  0bbbbbbb
// 2  11  110bbbbb 10bbbbbb
// 3  16  1110bbbb 10bbbbbb 10bbbbbb
// 4  21  11110bbb 10bbbbbb 10bbbbbb 10bbbbbb
// Each b represents a bit that can be used to store character data.

// input CANNOT have single byte upper half extended ascii codes

function numeric_entify_utf8 ($utf8_string) {

  $out = "";
  $ns = strlen ($utf8_string);
  for ($nn = 0; $nn < $ns; $nn++) {
    $ch = $utf8_string [$nn];
    $ii = ord ($ch);

//1 7 0bbbbbbb (127)

    if ($ii < 128) $out .= $ch;

//2 11 110bbbbb 10bbbbbb (2047)

   else if ($ii >>5 == 6) {
  $b1 = ($ii & 31);

  $nn++;
   $ch = $utf8_string [$nn];
    $ii = ord ($ch);
  $b2 = ($ii & 63);

  $ii = ($b1 * 64) + $b2;

      $ent = sprintf ("&#%d;", $ii);
      $out .= $ent;
    }

//3 16 1110bbbb 10bbbbbb 10bbbbbb

   else if ($ii >>4 == 14) {
  $b1 = ($ii & 31);

  $nn++;
   $ch = $utf8_string [$nn];
    $ii = ord ($ch);
  $b2 = ($ii & 63);

  $nn++;
   $ch = $utf8_string [$nn];
    $ii = ord ($ch);
  $b3 = ($ii & 63);

  $ii = ((($b1 * 64) + $b2) * 64) + $b3;

      $ent = sprintf ("&#%d;", $ii);
      $out .= $ent;
    }

//4 21 11110bbb 10bbbbbb 10bbbbbb 10bbbbbb

   else if ($ii >>3 == 30) {
  $b1 = ($ii & 31);

  $nn++;
   $ch = $utf8_string [$nn];
    $ii = ord ($ch);
  $b2 = ($ii & 63);

  $nn++;
   $ch = $utf8_string [$nn];
    $ii = ord ($ch);
  $b3 = ($ii & 63);

  $nn++;
   $ch = $utf8_string [$nn];
    $ii = ord ($ch);
  $b4 = ($ii & 63);

  $ii = ((((($b1 * 64) + $b2) * 64) + $b3) * 64) + $b4;

      $ent = sprintf ("&#%d;", $ii);
      $out .= $ent;
    }

  }
  return $out;
}

johan dot andersson at strateg dot se (05-May-2003 09:25)

A simple way to convert utf-8 encoded strings...
(PHP 4 >= 4.3.0)

<?php
$newstring = html_entity_decode(htmlentities($utf8_string, ENT_COMPAT, 'UTF-8'));
?>

(For 4.1.0 >= PHP < 4.3.0 use this function instead of html_entity_decode)

<?php
function unhtmlentities ($string)
{
    $trans_tbl = get_html_translation_table (HTML_ENTITIES);
    $trans_tbl = array_flip ($trans_tbl);
    return strtr ($string, $trans_tbl);
}

$newstring = unhtmlentities(htmlentities($utf8_string, ENT_COMPAT, 'UTF-8'));
?>

//Johan

(24-Feb-2003 02:10)

Oups, this is the non bugged version :)

Well sometimes you need to store a utf-8 string in a database table column with a fixed size.
Here is a function that fix a string which has been broken (by a substr for example) in a middle of a utf-8 char sequence.

function FixUtf8BrokenString($Desc)
{
 // UTF-8 encoding
 // bytes : representation
 // 1     : 0bbbbbbb
 // 2    : 110bbbbb 10bbbbbb
 // 3     : 1110bbbb 10bbbbbb 10bbbbbb
 // 4     : 11110bbb 10bbbbbb 10bbbbbb 10bbbbbb
 // to see if a string is broken in middle of a utf8 char
 // we search for last byte encoding size of utf-8 char
 // if number of last bytes in string is lower than encoding size
 // we remove those last bytes

 // if last byte is ord < 128, ok. we return !
 if (ord($Desc[strlen($Desc) - 1]) < (0x80))
   return $Desc

 // loop for finding byte encoding size
 $nbbytes = 1;
 while (ord($Desc[strlen($Desc) - $nbbytes]) > 0x7F)
 {
   if (ord($Desc[strlen($Desc) - $nbbytes]) > 0xBF)
     break;
   $nbbytes++;
 }

  // check if byte encoding size is encoding a size of 4 bytes
  if ((ord($Desc[strlen($Desc) - $nbbytes]) > 0xF0) && ($nbbytes == 4))
    return $Desc;
  // check if byte encoding size is encoding a size of 3 bytes
  if ((ord($Desc[strlen($Desc) - $nbbytes]) > 0xE0) && ($nbbytes == 3))
    return $Desc;
  // check if byte encoding size is encoding a size of 2 bytes
  if ((ord($Desc[strlen($Desc) - $nbbytes]) > 0xC0) && ($nbbytes == 2))
    return $Desc;
  // then this is the case where string is badly broken, we remove last bytes
  return substr($Desc, 0, -$nbbytes);
}

$str = "Ekonomi_ve_\xc4\xb0\xc5\x9f_D\xc3\xbcnyas\xc4\xb1";
$broken = substr($str, 0, 12);
$fixed = FixUtf8BrokenString($broken);

echo "$str<hr>$fixed<hr>$broken<hr>";

Sebastien Meudec.

(18-Dec-2002 05:08)

addition to above entrie:

it does not mean "when it comes to a '='" but when it comes to a "0"

mittag - -add- -marcmittag- -dot- -de (18-Dec-2002 04:56)

The above function does not work entirely correct. It comes to problems, if there is a leading "=" in one of the two Strings it produces and glues out of the two bytes of the unicode letter.

The following works:

<?php
//Convert Unicode to ASCII + Entities
$fp = fopen($DOCUMENT_ROOT."/your_unicode_text.txt", "r");
while ( !feof($fp) )
{ $string = fgets($fp, 1000);

 $utf2html_string .= $string;
}
$string2 = $utf2html_string;
fclose ( $fp);

function utf2html ()
{
global $utf2html_string;

$utf2html_retstr = "";
 for ($utf2html_p=0; $utf2html_p<strlen($utf2html_string); $utf2html_p++) {
 $utf2html_c = substr ($utf2html_string, $utf2html_p, 1);
 $utf2html_c1 = ord ($utf2html_c);
  if ($utf2html_c1>>5 == 6) {// 110x xxxx, 110 prefix for 2 bytes unicode
    $utf2html_p++;
   $utf2html_t = substr ($utf2html_string, $utf2html_p, 1);
  $utf2html_c2 = ord ($utf2html_t);
   $utf2html_c1 &= 31; // remove the 3 bit two bytes prefix
   $utf2html_c2 &= 63; // remove the 2 bit trailing byte prefix
   $utf2html_c2 |= (($utf2html_c1 & 3) << 6); // last 2 bits of c1 become first 2 of c2
   $utf2html_c1 >>= 2; // c1 shifts 2 to the right
   $a = dechex($utf2html_c1);
   $a = str_pad($a, 2, "0", STR_PAD_LEFT);
   $b = dechex($utf2html_c2);
   $b = str_pad($b, 2, "0", STR_PAD_LEFT);

   $utf2html_n_neu = $a.$b;
   $utf2html_n_neu_speicher = $utf2html_n_neu;
   $utf2html_n_neu = "&#x".$utf2html_n_neu.";";

    
 $utf2html_retstr .= $utf2html_n_neu;
 
  }
  else {
   $utf2html_retstr .= $utf2html_c;
  }
 }
 echo $utf2html_retstr;
 //return $utf2html_retstr;

}

utf2html();

?>

wielspm at xs4all dot nl (05-Dec-2002 05:44)

Here is a function I made to convert all 2 byte utf in a &#xxx; form:

function utf2html ($utf2html_string)
{
  $utf2html_retstr = "";
  for ($utf2html_p=0; $utf2html_p<strlen($utf2html_string); $utf2html_p++):
    $utf2html_c = substr ($utf2html_string, $utf2html_p, 1);
    $utf2html_c1 = ord ($utf2html_c);
    if ($utf2html_c1>>5 == 6): // 110x xxxx, 110 prefix for 2 bytes unicode
      $utf2html_p++;
       $utf2html_t = substr ($utf2html_string, $utf2html_p, 1);
      $utf2html_c2 = ord ($utf2html_t);
      $utf2html_c1 &= 31; // remove the 3 bit two bytes prefix
      $utf2html_c2 &= 63; // remove the 2 bit trailing byte prefix
      $utf2html_c2 |= (($utf2html_c1 & 3) << 6); // last 2 bits of c1 become first 2 of c2
      $utf2html_c1 >>= 2; // c1 shifts 2 to the right
       $utf2html_n = dechex($utf2html_c1).dechex($utf2html_c2);
      $utf2html_retstr .= sprintf ("&#%03d;", hexdec($utf2html_n));
    else:
      $utf2html_retstr .= $utf2html_c;
    endif;
  endfor;
  return $utf2html_retstr;
}

(27-Aug-2002 08:22)

echo utf8_decode(
"Ekonomi_ve_\xc4\xb0\xc5\x9f_D\xc3xbcnyas\xc4\xb1");

Outputs: Ekonomi_ve_??_Dnyas?

This is not a bug. For example "\xc4\xb0" is decoded like this:
0xC4 = 110 00100 (110 prefix for 2 bytes)
0xB0 = 10 110000 (10 for trailing byte)
Character = 001 0011 0000 = 0x130

This U+0130 Unicode character is not defined in ISO-8859-1
(where all codes are below 0x100), so the utf8_decode() function
cannot represent it, and inserts a '?' replacement character
in the result string...

There's no alternative in the utf8_decode() function
which returns a string made of
single-byte characters.

PHP really lacks a datatype for UTF-16 (a.k.a. Unicode) strings,
unlike Java whose strings are always natively encoded
with UTF-16...

The alternative for PHP would be that it allows inserting SGML
character entities. In the above example, it could return
"&#x130;" when decoding "\xc4\xb0".

May be a future version of PHP could make strings using
double-byte UTF-16 encoding, so that Unicode could be natively
supported, but this would require adding new functions to
define the behavior of I/O functions to provide external
encode/decode capabilities when sending Unicode strings to
a file stream, or with echo and print builtins for the
standard input and output streams:

- What would be the semantic of fwrite($fp, $string)
if $string can contain any UTF-16 characters ?
- Should fwrite() truncate the highest byte of each UTF-16
character, letting the user anticipating this truncation by
performing the conversion to UTF-8 or character entities himself ?
- Should the user be able to specify an encoder/decoder object
used by all I/O operations performed on a file ?

For example:
- set_encoder($fp, 'utf8_encode') would define the PHP function
to call to encode a string.
- set_encoder($fp) or set_encoder($fp, null) would restore the
default (stripping) encoder...
- then fwrite($fp, $string) would return the number of bytes
written to the stream, which may be larger than the length of
$string...

ronen at greyzone dot com (02-Mar-2002 01:37)

The following function will take a utf-8 encoded string and convert it to Unicode entities (the format is &#nnn; or &#nnnnn; with n={0..9} ).  Most browsers will display Unicode entities regardless of the encoding of the page.  Otherwise try charset=utf-8 to make sure the entities display correctly.  This works well with IE and Mozilla (tested with Mozilla 0.9.8 for X-Windos).

<?php
/**
* takes a string of utf-8 encoded characters and converts it to a string of unicode entities
* each unicode entitiy has the form &#nnnnn; n={0..9} and can be displayed by utf-8 supporting
* browsers
* @param $source string encoded using utf-8 [STRING]
* @return string of unicode entities [STRING]
* @access public
*/
function utf8ToUnicodeEntities ($source) {
    // array used to figure what number to decrement from character order value
    // according to number of characters used to map unicode to ascii by utf-8
    $decrement[4] = 240;
    $decrement[3] = 224;
    $decrement[2] = 192;
    $decrement[1] = 0;
   
    // the number of bits to shift each charNum by
    $shift[1][0] = 0;
    $shift[2][0] = 6;
    $shift[2][1] = 0;
    $shift[3][0] = 12;
    $shift[3][1] = 6;
    $shift[3][2] = 0;
    $shift[4][0] = 18;
    $shift[4][1] = 12;
    $shift[4][2] = 6;
    $shift[4][3] = 0;
   
    $pos = 0;
    $len = strlen ($source);
    $encodedString = '';
    while ($pos < $len) {
        $asciiPos = ord (substr ($source, $pos, 1));
        if (($asciiPos >= 240) && ($asciiPos <= 255)) {
            // 4 chars representing one unicode character
            $thisLetter = substr ($source, $pos, 4);
            $pos += 4;
        }
        else if (($asciiPos >= 224) && ($asciiPos <= 239)) {
            // 3 chars representing one unicode character
            $thisLetter = substr ($source, $pos, 3);
            $pos += 3;
        }
        else if (($asciiPos >= 192) && ($asciiPos <= 223)) {
            // 2 chars representing one unicode character
            $thisLetter = substr ($source, $pos, 2);
            $pos += 2;
        }
        else {
            // 1 char (lower ascii)
            $thisLetter = substr ($source, $pos, 1);
            $pos += 1;
        }

        // process the string representing the letter to a unicode entity
        $thisLen = strlen ($thisLetter);
        $thisPos = 0;
        $decimalCode = 0;
        while ($thisPos < $thisLen) {
            $thisCharOrd = ord (substr ($thisLetter, $thisPos, 1));
            if ($thisPos == 0) {
                $charNum = intval ($thisCharOrd - $decrement[$thisLen]);
                $decimalCode += ($charNum << $shift[$thisLen][$thisPos]);
            }
            else {
                $charNum = intval ($thisCharOrd - 128);
                $decimalCode += ($charNum << $shift[$thisLen][$thisPos]);
            }

            $thisPos++;
        }

        if ($thisLen == 1)
            $encodedLetter = "&#". str_pad($decimalCode, 3, "0", STR_PAD_LEFT) . ';';
        else
            $encodedLetter = "&#". str_pad($decimalCode, 5, "0", STR_PAD_LEFT) . ';';

        $encodedString .= $encodedLetter;
    }

    return $encodedString;
}
?>

Ronen.