iOS判断一段字符串长度(汉字2字节)

-(NSUInteger)textLength: (NSString *) text{

NSUInteger asciiLength = 0;

for (NSUInteger i = 0; i < text.length; i++) {

unichar uc = [text characterAtIndex: i];

asciiLength += isascii(uc) ? 1 : 2;
}

NSUInteger unicodeLength = asciiLength;

return unicodeLength;

}