PHP实现截取字符串的通用方法

1. /**
2. * 截取字符串
3. * params $string 要截取的字符串
4. * params $length: 保留长度（字符数）
5. * params $dot: 多余部分显示
6. **/
7. function _cutstr($string, $length, $dot = ' ...') {
8. if(strlen($string) return $string;
9. }
10. $string = str_replace(array('&', '"', ''), array('&', '"', ''), $string);
11. $strcut = '';
12. $n = $tn = $noc = 0;
13. while($n $t = ord($string[$n]);
14. if($t == 9 || $t == 10 || (32 $tn = 1; $n++; $noc++;
15. } elseif(194 $tn = 2; $n += 2; $noc += 2;
16. } elseif(224 $tn = 3; $n += 3; $noc += 2;
17. } elseif(240 $tn = 4; $n += 4; $noc += 2;
18. } elseif(248 $tn = 5; $n += 5; $noc += 2;
19. } elseif($t == 252 || $t == 253) {
20. $tn = 6; $n += 6; $noc += 2;
21. } else {
22. $n++;
23. }
24. if($noc >= $length) {
25. break;
26. }
27. }
28. if($noc > $length) {
29. $n -= $tn;
30. }
31. $strcut = substr($string, 0, $n);
32. $strcut = str_replace(array('&', '"', ''), array('&', '"', ''), $strcut);
33. return $strcut.$dot;
34. }

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PHP