Explication détaillée de l'exemple de code de fonction de chaîne chinoise d'interception THINKPHP

# 函数解释：
msubstr($str, $start=0, $length, $charset=”utf-8″, $suffix=true)
/*
$str:要截取的字符串
$start=0：开始位置，默认从0开始
$length：截取长度
$charset=”utf-8″：字符编码，默认UTF－8
$suffix=true：是否在截取后的字符后面显示省略号，默认true显示，false为不显示
*/

{$vo.title|msubstr=0,5,'utf-8',false}

function msubstr($str, $start=0, $length, $charset="utf-8", $suffix=true) 
{ 
 if(function_exists("mb_substr")){ 
 if($suffix) 
  return mb_substr($str, $start, $length, $charset)."..."; 
 else
  return mb_substr($str, $start, $length, $charset); 
 } 
 elseif(function_exists('iconv_substr')) { 
 if($suffix) 
  return iconv_substr($str,$start,$length,$charset)."..."; 
 else
  return iconv_substr($str,$start,$length,$charset); 
 } 
 $re['utf-8'] = "/[x01-x7f]|[xc2-xdf][x80-xbf]|[xe0-xef][x80-xbf]{2}|[xf0-xff][x80-xbf]{3}/"; 
 $re['gb2312'] = "/[x01-x7f]|[xb0-xf7][xa0-xfe]/"; 
 $re['gbk']  = "/[x01-x7f]|[x81-xfe][x40-xfe]/"; 
 $re['big5']  = "/[x01-x7f]|[x81-xfe]([x40-x7e]|xa1-xfe])/"; 
 preg_match_all($re[$charset], $str, $match); 
 $slice = join("",array_slice($match[0], $start, $length)); 
 if($suffix) return $slice."…"; 
 return $slice;
}