rewriting utf8 encoding function. preg_replace is safer that splitting into

arrays. now function will support all symbols until somebody comes up with
symbol No 2^31+1 :)

functions/encode/utf_8.php

@@ -1,87 +1,119 @@
 <?php
 /**
- * utf-8 encoding function
+ * utf-8 encoding functions
  *
  * takes a string of unicode entities and converts it to a utf-8 encoded string
  * each unicode entitiy has the form &#nnn(nn); n={0..9} and can be displayed by utf-8 supporting
- * browsers.  Ascii will not be modified.
+ * browsers. Ascii will not be modified.
  *
- * code is taken from www.php.net manual comments
- * Author: ronen at greyzone dot com
+ * Original code is taken from www.php.net manual comments
+ * Original author: ronen at greyzone dot com
  *
  * @version $Id$
+ * @copyright Copyright &copy; SquirrelMail Development Team, 2004
  * @package squirrelmail
  * @subpackage encode
  */
 
 /**
  * Converts string to utf-8
- * @param $source string of unicode entities [STRING]
- * @return a utf-8 encoded string [STRING]
+ * @param string $string text with numeric unicode entities
+ * @return string utf-8 encoded text
  */
-function charset_encode_utf_8 ($source) {
+function charset_encode_utf_8 ($string) {
+   // don't run encoding function, if there is no encoded characters
+   if (! preg_match("'&#[0-9]+;'",$string) ) return $string;
 
-   // don't run though encoding function, if there is no encoded characters
-   if (! preg_match("'&#'",$source) ) return $source;
+    $string=preg_replace("/&#([0-9]+);/e","unicodetoutf8('\\1')",$string);
+    // $string=preg_replace("/&#[xX]([0-9A-F]+);/e","unicodetoutf8(hexdec('\\1'))",$string);
+    
+    return $string;
+}
+
+/**
+ * Return utf8 symbol when unicode character number is provided
+ * 
+ * This function is used internally by charset_encode_utf_8 
+ * function. It might be unavailable to other squirrelmail functions.
+ * Don't use it or make sure, that functions/encode/utf_8.php is 
+ * included. 
+ *
+ * @param int $var decimal unicode value
+ * @return string utf8 character
+ */
+function unicodetoutf8($var) {
+
+    if ($var < 128) {
+        $ret = chr ($var);
+    } else if ($var < 2048) {
+        // Two byte utf-8
+        $binVal = str_pad (decbin ($var), 11, "0", STR_PAD_LEFT);
+        $binPart1 = substr ($binVal, 0, 5);
+        $binPart2 = substr ($binVal, 5);
+        
+        $char1 = chr (192 + bindec ($binPart1));
+        $char2 = chr (128 + bindec ($binPart2));
+        $ret = $char1 . $char2;
+    } else if ($var < 65536) {
+        // Three byte utf-8
+        $binVal = str_pad (decbin ($var), 16, "0", STR_PAD_LEFT);
+        $binPart1 = substr ($binVal, 0, 4);
+        $binPart2 = substr ($binVal, 4, 6);
+        $binPart3 = substr ($binVal, 10);
+
+        $char1 = chr (224 + bindec ($binPart1));
+        $char2 = chr (128 + bindec ($binPart2));
+        $char3 = chr (128 + bindec ($binPart3));
+        $ret = $char1 . $char2 . $char3;
+    } else if ($var < 2097152) {
+        // Four byte utf-8
+        $binVal = str_pad (decbin ($var), 21, "0", STR_PAD_LEFT);
+        $binPart1 = substr ($binVal, 0, 3);
+        $binPart2 = substr ($binVal, 3, 6);
+        $binPart3 = substr ($binVal, 9, 6);
+        $binPart4 = substr ($binVal, 15);
 
-   $utf8Str = '';
-   $entityArray = explode ("&#", $source);
-   $size = count ($entityArray);
-   for ($i = 0; $i < $size; $i++) {
-       $subStr = $entityArray[$i];
-       $nonEntity = strstr ($subStr, ';');
-       if ($nonEntity !== false) {
-           $unicode = intval (substr ($subStr, 0, (strpos ($subStr, ';') + 1)));
-           // determine how many chars are needed to reprsent this unicode char
-           if ($unicode < 128) {
-               $utf8Substring = chr ($unicode);
-           }
-           else if ($unicode >= 128 && $unicode < 2048) {
-               $binVal = str_pad (decbin ($unicode), 11, "0", STR_PAD_LEFT);
-               $binPart1 = substr ($binVal, 0, 5);
-               $binPart2 = substr ($binVal, 5);
-          
-               $char1 = chr (192 + bindec ($binPart1));
-               $char2 = chr (128 + bindec ($binPart2));
-               $utf8Substring = $char1 . $char2;
-           }
-           else if ($unicode >= 2048 && $unicode < 65536) {
-               $binVal = str_pad (decbin ($unicode), 16, "0", STR_PAD_LEFT);
-               $binPart1 = substr ($binVal, 0, 4);
-               $binPart2 = substr ($binVal, 4, 6);
-               $binPart3 = substr ($binVal, 10);
-          
-               $char1 = chr (224 + bindec ($binPart1));
-               $char2 = chr (128 + bindec ($binPart2));
-               $char3 = chr (128 + bindec ($binPart3));
-               $utf8Substring = $char1 . $char2 . $char3;
-           }
-           else {
-               $binVal = str_pad (decbin ($unicode), 21, "0", STR_PAD_LEFT);
-               $binPart1 = substr ($binVal, 0, 3);
-               $binPart2 = substr ($binVal, 3, 6);
-               $binPart3 = substr ($binVal, 9, 6);
-               $binPart4 = substr ($binVal, 15);
-      
-               $char1 = chr (240 + bindec ($binPart1));
-               $char2 = chr (128 + bindec ($binPart2));
-               $char3 = chr (128 + bindec ($binPart3));
-               $char4 = chr (128 + bindec ($binPart4));
-               $utf8Substring = $char1 . $char2 . $char3 . $char4;
-           }
-          
-           if (strlen ($nonEntity) > 1)
-               $nonEntity = substr ($nonEntity, 1); // chop the first char (';')
-           else
-               $nonEntity = '';
+        $char1 = chr (240 + bindec ($binPart1));
+        $char2 = chr (128 + bindec ($binPart2));
+        $char3 = chr (128 + bindec ($binPart3));
+        $char4 = chr (128 + bindec ($binPart4));
+        $ret = $char1 . $char2 . $char3 . $char4;
+    } else if ($var < 67108864) {
+        // Five byte utf-8
+        $binVal = str_pad (decbin ($var), 26, "0", STR_PAD_LEFT);
+        $binPart1 = substr ($binVal, 0, 2);
+        $binPart2 = substr ($binVal, 2, 6);
+        $binPart3 = substr ($binVal, 8, 6);
+        $binPart4 = substr ($binVal, 14,6);
+        $binPart5 = substr ($binVal, 20);
 
-           $utf8Str .= $utf8Substring . $nonEntity;
-       }
-       else {
-           $utf8Str .= $subStr;
-       }
-   }
+        $char1 = chr (248 + bindec ($binPart1));
+        $char2 = chr (128 + bindec ($binPart2));
+        $char3 = chr (128 + bindec ($binPart3));
+        $char4 = chr (128 + bindec ($binPart4));
+        $char5 = chr (128 + bindec ($binPart5));
+        $ret = $char1 . $char2 . $char3 . $char4 . $char5;
+    } else if ($var < 2147483648) {
+        // Six byte utf-8
+        $binVal = str_pad (decbin ($var), 31, "0", STR_PAD_LEFT);
+        $binPart1 = substr ($binVal, 0, 1);
+        $binPart2 = substr ($binVal, 1, 6);
+        $binPart3 = substr ($binVal, 7, 6);
+        $binPart4 = substr ($binVal, 13,6);
+        $binPart5 = substr ($binVal, 19,6);
+        $binPart6 = substr ($binVal, 25);
 
-   return $utf8Str;
+        $char1 = chr (252 + bindec ($binPart1));
+        $char2 = chr (128 + bindec ($binPart2));
+        $char3 = chr (128 + bindec ($binPart3));
+        $char4 = chr (128 + bindec ($binPart4));
+        $char5 = chr (128 + bindec ($binPart5));
+        $char6 = chr (128 + bindec ($binPart6));
+        $ret = $char1 . $char2 . $char3 . $char4 . $char5 . $char6;
+    } else {
+        // there is no such symbol in utf-8
+        $ret='?';
+    }
+    return $ret;
 }
 ?>