Why reinventing the wheel, if there is an excellent implementation of utf8/unicode conversion here:
http://iki.fi/hsivonen/php-utf8/
<?php
/* ***** BEGIN LICENSE BLOCK *****
* Version: NPL 1.1/GPL 2.0/LGPL 2.1
*
* Download: http://hsivonen.iki.fi/php-utf8/
*
* The contents of this file are subject to the Netscape 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/NPL/
*
* 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 Communicator client code.
*
* The Initial Developer of the Original Code is
* Netscape Communications Corporation.
* Portions created by the Initial Developer are Copyright (C) 1998
* the Initial Developer. All Rights Reserved.
*
* Contributor(s):
* Henri Sivonen, hsivonen@iki.fi
*
*
* 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
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* decision by deleting the provisions above and replace them with the notice
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* the provisions above, a recipient may use your version of this file under
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*
* ***** END LICENSE BLOCK ***** */
/*
* For the original C++ code, see
* http://lxr.mozilla.org/seamonkey/source/intl/uconv/src/nsUTF8ToUnicode.cpp
* http://lxr.mozilla.org/seamonkey/source/intl/uconv/src/nsUnicodeToUTF8.cpp
*
* The latest version of this file can be obtained from
* http://iki.fi/hsivonen/php-utf8/
*
* Version 1.0, 2003-05-30
*/
/**
* Takes an UTF-8 string and returns an array of ints representing the
* Unicode characters. Astral planes are supported ie. the ints in the
* output can be > 0xFFFF. Occurrances of the BOM are ignored. Surrogates
* are not allowed.
*
* Returns false if the input string isn't a valid UTF-8 octet sequence.
*/
function utf8ToUnicode(&$str)
{
$mState = 0; // cached expected number of octets after the current octet
// until the beginning of the next UTF8 character sequence
$mUcs4 = 0; // cached Unicode character
$mBytes = 1; // cached expected number of octets in the current sequence
$out = array();
$len = strlen($str);
for($i = 0; $i < $len; $i++) {
$in = ord($str{$i});
if (0 == $mState) {
// When mState is zero we expect either a US-ASCII character or a
// multi-octet sequence.
if (0 == (0x80 & ($in))) {
// US-ASCII, pass straight through.
$out[] = $in;
$mBytes = 1;
} else if (0xC0 == (0xE0 & ($in))) {
// First octet of 2 octet sequence
$mUcs4 = ($in);
$mUcs4 = ($mUcs4 & 0x1F) << 6;
$mState = 1;
$mBytes = 2;
} else if (0xE0 == (0xF0 & ($in))) {
// First octet of 3 octet sequence
$mUcs4 = ($in);
$mUcs4 = ($mUcs4 & 0x0F) << 12;
$mState = 2;
$mBytes = 3;
} else if (0xF0 == (0xF8 & ($in))) {
// First octet of 4 octet sequence
$mUcs4 = ($in);
$mUcs4 = ($mUcs4 & 0x07) << 18;
$mState = 3;
$mBytes = 4;
} else if (0xF8 == (0xFC & ($in))) {
/* First octet of 5 octet sequence.
*
* This is illegal because the encoded codepoint must be either
* (a) not the shortest form or
* (b) outside the Unicode range of 0-0x10FFFF.
* Rather than trying to resynchronize, we will carry on until the end
* of the sequence and let the later error handling code catch it.
*/
$mUcs4 = ($in);
$mUcs4 = ($mUcs4 & 0x03) << 24;
$mState = 4;
$mBytes = 5;
} else if (0xFC == (0xFE & ($in))) {
// First octet of 6 octet sequence, see comments for 5 octet sequence.
$mUcs4 = ($in);
$mUcs4 = ($mUcs4 & 1) << 30;
$mState = 5;
$mBytes = 6;
} else {
/* Current octet is neither in the US-ASCII range nor a legal first
* octet of a multi-octet sequence.
*/
return false;
}
} else {
// When mState is non-zero, we expect a continuation of the multi-octet
// sequence
if (0x80 == (0xC0 & ($in))) {
// Legal continuation.
$shift = ($mState - 1) * 6;
$tmp = $in;
$tmp = ($tmp & 0x0000003F) << $shift;
$mUcs4 |= $tmp;
if (0 == --$mState) {
/* End of the multi-octet sequence. mUcs4 now contains the final
* Unicode codepoint to be output
*
* Check for illegal sequences and codepoints.
*/
// From Unicode 3.1, non-shortest form is illegal
if (((2 == $mBytes) && ($mUcs4 < 0x0080)) ||
((3 == $mBytes) && ($mUcs4 < 0x0800)) ||
((4 == $mBytes) && ($mUcs4 < 0x10000)) ||
(4 < $mBytes) ||
// From Unicode 3.2, surrogate characters are illegal
(($mUcs4 & 0xFFFFF800) == 0xD800) ||
// Codepoints outside the Unicode range are illegal
($mUcs4 > 0x10FFFF)) {
return false;
}
if (0xFEFF != $mUcs4) {
// BOM is legal but we don't want to output it
$out[] = $mUcs4;
}
//initialize UTF8 cache
$mState = 0;
$mUcs4 = 0;
$mBytes = 1;
}
} else {
/* ((0xC0 & (*in) != 0x80) && (mState != 0))
*
* Incomplete multi-octet sequence.
*/
return false;
}
}
}
return $out;
}
/**
* Takes an array of ints representing the Unicode characters and returns
* a UTF-8 string. Astral planes are supported ie. the ints in the
* input can be > 0xFFFF. Occurrances of the BOM are ignored. Surrogates
* are not allowed.
*
* Returns false if the input array contains ints that represent
* surrogates or are outside the Unicode range.
*/
function unicodeToUtf8(&$arr)
{
$dest = '';
foreach ($arr as $src) {
if($src < 0) {
return false;
} else if ( $src <= 0x007f) {
$dest .= chr($src);
} else if ($src <= 0x07ff) {
$dest .= chr(0xc0 | ($src >> 6));
$dest .= chr(0x80 | ($src & 0x003f));
} else if($src == 0xFEFF) {
// nop -- zap the BOM
} else if ($src >= 0xD800 && $src <= 0xDFFF) {
// found a surrogate
return false;
} else if ($src <= 0xffff) {
$dest .= chr(0xe0 | ($src >> 12));
$dest .= chr(0x80 | (($src >> 6) & 0x003f));
$dest .= chr(0x80 | ($src & 0x003f));
} else if ($src <= 0x10ffff) {
$dest .= chr(0xf0 | ($src >> 18));
$dest .= chr(0x80 | (($src >> 12) & 0x3f));
$dest .= chr(0x80 | (($src >> 6) & 0x3f));
$dest .= chr(0x80 | ($src & 0x3f));
} else {
// out of range
return false;
}
}
return $dest;
}
?>The following uniord function is simpler and more efficient than any of the ones suggested without depending on mbstring or iconv. It's also more validating (code points above U+10FFFF are invalid; sequences starting with 0xC0 and 0xC1 are invalid overlong encodings of characters below U+0080), though not entirely validating, so it still assumes proper input.
<?php
function uniord($c) {
$h = ord($c{0});
if ($h <= 0x7F) {
return $h;
} else if ($h < 0xC2) {
return false;
} else if ($h <= 0xDF) {
return ($h & 0x1F) << 6 | (ord($c{1}) & 0x3F);
} else if ($h <= 0xEF) {
return ($h & 0x0F) << 12 | (ord($c{1}) & 0x3F) << 6
| (ord($c{2}) & 0x3F);
} else if ($h <= 0xF4) {
return ($h & 0x0F) << 18 | (ord($c{1}) & 0x3F) << 12
| (ord($c{2}) & 0x3F) << 6
| (ord($c{3}) & 0x3F);
} else {
return false;
}
}
?>
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