php 汉字截取

aliounian

1. 传入的参数中，$str是被截取的字符串，$start是从第几个字符串开始截取，$lenth表示需要截取几个字符串(包括中文)

1. function subString_UTF8($str, $start, $lenth)
   
2. {
   
3.     $len = strlen($str);
   
4.     $r = array();
   
5.     $n = 0;
   
6.     $m = 0;
   
7.     for($i = 0; $i < $len; $i++) {
   
8.         $x = substr($str, $i, 1);
   
9.         $a = base_convert(ord($x), 10, 2);
   
10.         $a = substr('00000000'.$a, -8);
    
11.         if ($n < $start){
    
12.             if (substr($a, 0, 1) == 0) {
    
13.             }elseif (substr($a, 0, 3) == 110) {
    
14.                 $i += 1;
    
15.             }elseif (substr($a, 0, 4) == 1110) {
    
16.                 $i += 2;
    
17.             }
    
18.             $n++;
    
19.         }else{
    
20.             if (substr($a, 0, 1) == 0) {
    
21.                 $r[ ] = substr($str, $i, 1);
    
22.             }elseif (substr($a, 0, 3) == 110) {
    
23.                 $r[ ] = substr($str, $i, 2);
    
24.                 $i += 1;
    
25.             }elseif (substr($a, 0, 4) == 1110) {
    
26.                 $r[ ] = substr($str, $i, 3);
    
27.                 $i += 2;
    
28.             }else{
    
29.                 $r[ ] = '';
    
30.             }
    
31.             if (++$m >= $lenth){
    
32.                 break;
    
33.             }
    
34.         }
    
35.     }
    
36.     return $r;
    
37. } // End subString_UTF8;