iOS NSString 计算中英文字符长度

-(int)convertToInt:(NSString*)strtemp
{
    int strlength = 0;
    char* p = (char*)[strtemp cStringUsingEncoding:NSUnicodeStringEncoding];
    for (int i=0 ; i<[strtemp lengthOfBytesUsingEncoding:NSUnicodeStringEncoding] ;i++) {
        if (*p) {
            p++;
            strlength++;
        }
        else {
            p++;
        }
    }
    return strlength;
}
-(int)getToInt:(NSString*)strtemp
{
    NSStringEncoding enc = CFStringConvertEncodingToNSStringEncoding(kCFStringEncodingGB_18030_2000);
    NSData* da = [strtemp dataUsingEncoding:enc];
    return[da length];
}