Filter all emoji from nsstring

NSString_Filter_Emoji

- (NSString*)removeEmoji:(NSString *)username {
    __block NSMutableString* temp = [NSMutableString string];
    
    [username enumerateSubstringsInRange:NSMakeRange(0, [username length]) options:NSStringEnumerationByComposedCharacterSequences usingBlock:
     ^(NSString *substring, NSRange substringRange, NSRange enclosingRange, BOOL *stop) {
         
         const unichar hs = [substring characterAtIndex: 0];
         
         // surrogate pair
         if (0xd800 <= hs && hs <= 0xdbff) {
             const unichar ls = [substring characterAtIndex: 1];
             const int uc = ((hs - 0xd800) * 0x400) + (ls - 0xdc00) + 0x10000;
             
             [temp appendString: (0x1d000 <= uc && uc <= 0x1f77f)? @"": substring]; // U+1D000-1F77F
             
             // non surrogate
         } else {
             [temp appendString: (0x2100 <= hs && hs <= 0x26ff)? @"": substring]; // U+2100-26FF
         }
     }];
    
    return temp;
}