squirrelmail/functions/decode/utf_8.php
2012-01-02 02:09:17 +00:00

94 lines
3.4 KiB
PHP

<?php
/**
* functions/decode/utf-8.php - utf-8 decoding functions
*
* This file contains utf-8 decoding function that is needed to read
* utf-8 encoded mails in non-utf-8 locale.
*
* Every decoded character consists of n bytes. First byte is octal
* 300-375, other bytes - always octals 200-277.
*<pre>
* Ranges (first byte):
* oct dec hex
* Two byte - 300-337 192-223 C0-DF
* Three byte - 340-357 224-239 E0-EF
* Four byte - 360-367 240-247 F0-F7
* Five byte - 370-373 248-251 F8-FB
* Six byte - 374-375 252-253 FC-FD
*
* \a\b characters are decoded to html code calculated with formula:
* octdec(a-300)*64 + octdec(b-200)
*
* \a\b\c characters are decoded to html code calculated with formula:
* octdec(a-340)*64^2 + octdec(b-200)*64 + octdec(c-200)
*
* \a\b\c\d characters are decoded to html code calculated with formula:
* octdec(a-360)*64^3 + octdec(b-200)*64^2 +
* + octdec(c-200)*64 + octdec(d-200)
*
* \a\b\c\d\e characters are decoded to html code calculated with formula:
* octdec(a-370)*64^4 + octdec(b-200)*64^3 +
* + octdec(c-200)*64^2 + octdec(d-200)*64 + octdec(e-200)
*
* \a\b\c\d\e\f characters are decoded to html code calculated with formula:
* octdec(a-374)*64^5 + octdec(b-200)*64^4 + octdec(c-200)*64^3 +
* + octdec(d-200)*64^2 + octdec(e-200)*64 + octdec(f-200)
*</pre>
* @copyright 2003-2012 The SquirrelMail Project Team
* @license http://opensource.org/licenses/gpl-license.php GNU Public License
* @version $Id$
* @package squirrelmail
* @subpackage decode
*/
/**
* Decode utf-8 strings
* @param string $string Encoded string
* @return string Decoded string
*/
function charset_decode_utf_8 ($string) {
global $squirrelmail_language;
// Japanese translation uses mbstring function to read utf-8
if ($squirrelmail_language == 'ja_JP')
return $string;
// don't do decoding when there are no 8bit symbols
if (! sq_is8bit($string,'utf-8'))
return $string;
// decode six byte unicode characters
/* (i think currently there is no such symbol)
$string = preg_replace("/([\374-\375])([\200-\277])([\200-\277])([\200-\277])([\200-\277])([\200-\277])/e",
"'&#'.((ord('\\1')-252)*1073741824+(ord('\\2')-200)*16777216+(ord('\\3')-200)*262144+(ord('\\4')-128)*4096+(ord('\\5')-128)*64+(ord('\\6')-128)).';'",
$string);
*/
// decode five byte unicode characters
/* (i think currently there is no such symbol)
$string = preg_replace("/([\370-\373])([\200-\277])([\200-\277])([\200-\277])([\200-\277])/e",
"'&#'.((ord('\\1')-248)*16777216+(ord('\\2')-200)*262144+(ord('\\3')-128)*4096+(ord('\\4')-128)*64+(ord('\\5')-128)).';'",
$string);
*/
// decode four byte unicode characters
$string = preg_replace("/([\360-\367])([\200-\277])([\200-\277])([\200-\277])/e",
"'&#'.((ord('\\1')-240)*262144+(ord('\\2')-128)*4096+(ord('\\3')-128)*64+(ord('\\4')-128)).';'",
$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);
// remove broken unicode
$string = preg_replace("/[\200-\237]|\240|[\241-\377]/",'?',$string);
return $string;
}