Use C # to intercept the Simplified Chinese/English string of the specified length

I wrote an article long ago. Article (Use C # to intercept a specified string of both Chinese and English characters), but the performance is not tested. Some people say that the performance of the method I wrote is incorrect. Later I thought, it may be necessary for BT to input a string of tens of thousands of K or even several Mb, which will affect the speed of regular match. For example, it is very likely to be used in the article system, today is a little time. I just improved it, Code As follows:

Public   Static   String Getstr ( String S, Int L, String Endstr)
{
String Temp = S. substring ( 0 , (S. Length < L) ? S. Length: l );

If (RegEx. Replace (temp, " [\ U4e00-\ u9fa5] " , " Zz " , Regexoptions. ignorecase). Length <= L)
{
ReturnTemp;
}
For ( Int I = Temp. length; I > = 0 ; I -- )
{
Temp = Temp. substring ( 0 , I );
If (RegEx. Replace (temp, " [\ U4e00-\ u9fa5] " , " Zz " , Regexoptions. ignorecase). Length <= L - Endstr. length)
{
ReturnTemp+Endstr;
}
}
Return Endstr;
}

The modified method adds a parameter"StringEndstr", Refers to when the string"StringS"Exceeds the specified length"IntL"For example, do you want to add the ellipsis "..." or other characters to the end.
In addition, after a ellipsis is added, the ellipsis length is included in the result length.

Usage example:

Getstr ("China 1 China Medium 1111 China", 23 ,"")
// Output: China 1 China Medium 1111 China

Getstr ("China 1 China Medium 1111 China", 23 ,"...")
// Output: China 1. China (China) 1111...

Getstr ("China 1 China Middle 1111 China", 23 ,"")
// Output: China 1 China Medium 1111 China

Getstr ("China 1 China Medium 1111 China", 23 ,"...")
// Output: China 1. China (China) 1111...

----------------------------------------------------------------------

Supplement: "Kpz" replied that the above method would intercept distortion, and I could not perform exhaustive testing, so I used another method, in order to consider the performance results, the logic was a bit dizzy and tested multiple times. The Code is as follows:

Public   Static   String Getstr2 ( String S, Int L, String Endstr)
{
String Temp = S. substring ( 0 , (S. Length < L + 1 ) ? S. Length: l + 1 );
Byte [] Encodedbytes = System. Text. asciiencoding. ASCII. getbytes (temp );

String Outputstr =   "" ;
Int Count =   0 ;

For ( Int I =   0 ; I < Temp. length; I ++ )
{
If (( Int ) Encodedbytes [I] =   63 )
Count + =   2 ;
Else
Count + =   1 ;

If (Count <= L - Endstr. length)
Outputstr + = Temp. substring (I, 1 );
Else   If (Count > L)
Break ;
}  

If (Count <= L)
{
Outputstr=Temp;
Endstr="";
}

Outputstr + = Endstr;

Return Outputstr;
}

The usage and parameter meanings are the same as before. Note that the ellipsis also occupies the position and the length is calculated.