functions/encode/utf_8.php

   1 <?php
   2
   3 /**
   4  * utf-8 encoding functions
   5  *
   6  * takes a string of unicode entities and converts it to a utf-8 encoded string
   7  * each unicode entitiy has the form &#nnn(nn); n={0..9} and can be displayed by utf-8 supporting
   8  * browsers. Ascii will not be modified.
   9  *
  10  * Original code is taken from www.php.net manual comments
  11  * Original author: ronen at greyzone dot com
  12  *
  13  * @copyright 2004-2021 The SquirrelMail Project Team
  14  * @license http://opensource.org/licenses/gpl-license.php GNU Public License
  15  * @version $Id$
  16  * @package squirrelmail
  17  * @subpackage encode
  18  */
  19
  20 /**
  21  * Converts string to utf-8
  22  * @param string $string text with numeric unicode entities
  23  * @return string utf-8 encoded text
  24  */
  25 function charset_encode_utf_8 ($string) {
  26    // don't run encoding function, if there is no encoded characters
  27    if (! preg_match("'&#[0-9]+;'",$string) ) return $string;
  28
  29     $string=preg_replace_callback("/&#([0-9]+);/",'unicodetoutf8',$string);
  30
  31     return $string;
  32 }
  33
  34 /**
  35  * Return utf8 symbol when unicode character number is provided
  36  *
  37  * This function is used internally by charset_encode_utf_8
  38  * function. It might be unavailable to other SquirrelMail functions.
  39  * Don't use it or make sure, that functions/encode/utf_8.php is
  40  * included.
  41  *
  42  * @param array $matches array with first element a decimal unicode value
  43  * @return string utf8 character
  44  */
  45 function unicodetoutf8($matches) {
  46     $var = $matches[1];
  47
  48     if ($var < 128) {
  49         $ret = chr ($var);
  50     } else if ($var < 2048) {
  51         // Two byte utf-8
  52         $binVal = str_pad (decbin ($var), 11, "0", STR_PAD_LEFT);
  53         $binPart1 = substr ($binVal, 0, 5);
  54         $binPart2 = substr ($binVal, 5);
  55
  56         $char1 = chr (192 + bindec ($binPart1));
  57         $char2 = chr (128 + bindec ($binPart2));
  58         $ret = $char1 . $char2;
  59     } else if ($var < 65536) {
  60         // Three byte utf-8
  61         $binVal = str_pad (decbin ($var), 16, "0", STR_PAD_LEFT);
  62         $binPart1 = substr ($binVal, 0, 4);
  63         $binPart2 = substr ($binVal, 4, 6);
  64         $binPart3 = substr ($binVal, 10);
  65
  66         $char1 = chr (224 + bindec ($binPart1));
  67         $char2 = chr (128 + bindec ($binPart2));
  68         $char3 = chr (128 + bindec ($binPart3));
  69         $ret = $char1 . $char2 . $char3;
  70     } else if ($var < 2097152) {
  71         // Four byte utf-8
  72         $binVal = str_pad (decbin ($var), 21, "0", STR_PAD_LEFT);
  73         $binPart1 = substr ($binVal, 0, 3);
  74         $binPart2 = substr ($binVal, 3, 6);
  75         $binPart3 = substr ($binVal, 9, 6);
  76         $binPart4 = substr ($binVal, 15);
  77
  78         $char1 = chr (240 + bindec ($binPart1));
  79         $char2 = chr (128 + bindec ($binPart2));
  80         $char3 = chr (128 + bindec ($binPart3));
  81         $char4 = chr (128 + bindec ($binPart4));
  82         $ret = $char1 . $char2 . $char3 . $char4;
  83     } else if ($var < 67108864) {
  84         // Five byte utf-8
  85         $binVal = str_pad (decbin ($var), 26, "0", STR_PAD_LEFT);
  86         $binPart1 = substr ($binVal, 0, 2);
  87         $binPart2 = substr ($binVal, 2, 6);
  88         $binPart3 = substr ($binVal, 8, 6);
  89         $binPart4 = substr ($binVal, 14,6);
  90         $binPart5 = substr ($binVal, 20);
  91
  92         $char1 = chr (248 + bindec ($binPart1));
  93         $char2 = chr (128 + bindec ($binPart2));
  94         $char3 = chr (128 + bindec ($binPart3));
  95         $char4 = chr (128 + bindec ($binPart4));
  96         $char5 = chr (128 + bindec ($binPart5));
  97         $ret = $char1 . $char2 . $char3 . $char4 . $char5;
  98     } else if ($var < 2147483648) {
  99         // Six byte utf-8
 100         $binVal = str_pad (decbin ($var), 31, "0", STR_PAD_LEFT);
 101         $binPart1 = substr ($binVal, 0, 1);
 102         $binPart2 = substr ($binVal, 1, 6);
 103         $binPart3 = substr ($binVal, 7, 6);
 104         $binPart4 = substr ($binVal, 13,6);
 105         $binPart5 = substr ($binVal, 19,6);
 106         $binPart6 = substr ($binVal, 25);
 107
 108         $char1 = chr (252 + bindec ($binPart1));
 109         $char2 = chr (128 + bindec ($binPart2));
 110         $char3 = chr (128 + bindec ($binPart3));
 111         $char4 = chr (128 + bindec ($binPart4));
 112         $char5 = chr (128 + bindec ($binPart5));
 113         $char6 = chr (128 + bindec ($binPart6));
 114         $ret = $char1 . $char2 . $char3 . $char4 . $char5 . $char6;
 115     } else {
 116         // there is no such symbol in utf-8
 117         $ret='?';
 118     }
 119     return $ret;
 120 }