PHP instance-string segmentation (perfect support for both Chinese and English, compatible with mb_substr)

/**
+ ----------------------------------------------------------
* String truncation, supporting Chinese and other Encoding
+ ----------------------------------------------------------
* @ Static
* @ Access public
+ ----------------------------------------------------------
* @ Param string $ STR string to be converted
* @ Param string $ start position
* @ Param string $ length truncation Length
* @ Param string $ charset encoding format
* @ Param string $ suffix truncated display characters
+ ----------------------------------------------------------
* @ Return string
+ ----------------------------------------------------------
*/ 
FunctionMsubstr ($ Str,$ Start,$ Length,$ Charset= "UTF-8 ",$ Suffix=True) 
 { 
 If(Function_exists("Mb_substr ")){ 
 $ Slice= Mb_substr ($ Str,$ Start,$ Length,$ Charset); 
}Elseif(Function_exists('Iconv _ substr ')){ 
 $ Slice=Iconv_substr($ Str,$ Start,$ Length,$ Charset); 
 If(False===$ Slice){ 
 $ Slice= ''; 
 } 
}Else{ 
 $ 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)); 
 } 
 Return $ Suffix?$ Slice.'...':$ Slice; 
}