自己写的php中文截取函数mb_strlen和mb_substr
众所周知，php自带的strlen与substr函数没法处理中文字符，于是，我们会用mb_系列函数替代。但是，没有mbstring库怎么办？这就需要我们自己写一个来替代了，废话不多说，先上代码:
if(!function_exists('mb_strlen')){
functionmb_strlen($text,$encode){
if($encode=='UTF-8'){
returnpreg_match_all('%(?:
[\x09\x0A\x0D\x20-\x7E] #ASCII
|[\xC2-\xDF][\x80-\xBF] #non-overlong2-byte
| \xE0[\xA0-\xBF][\x80-\xBF] #excludingoverlongs
|[\xE1-\xEC\xEE\xEF][\x80-\xBF]{2}#straight3-byte
| \xED[\x80-\x9F][\x80-\xBF] #excludingsurrogates
| \xF0[\x90-\xBF][\x80-\xBF]{2} #planes1-3
|[\xF1-\xF3][\x80-\xBF]{3} #planes4-15
| \xF4[\x80-\x8F][\x80-\xBF]{2} #plane16
)%xs',$text,$out);
}else{
returnstrlen($text);
}
}
}
/*fromInternet,authorunknown*/ if(!function_exists('mb_substr')){ functionmb_substr($str,$start,$len='',$encoding="UTF-8"){ $limit=strlen($str); for($s=0;$start>0;--$start){//foundtherealstart if($s>=$limit) break; if($str[$s]<="\x7F") ++$s; else{ ++$s;//skiplength while($str[$s]>="\x80"&&$str[$s]<="\xBF") ++$s; } } if($len=='') returnsubstr($str,$s); else for($e=$s;$len>0;--$len){//foundtherealend if($e>=$limit) break; if($str[$e]<="\x7F") ++$e; else{ ++$e;//skiplength while($str[$e]>="\x80"&&$str[$e]<="\xBF"&&$e<$limit) ++$e; } } returnsubstr($str,$s,$e-$s); } }