计算日期的原生算法，用于计算日期到天数，或者天数到日期，不依赖任何操作系统；经过实用验证无误；没有1970年的限制；-Calculation date native algorithm for calculating the number of days to a date or number of days to date, does not rely on any operating system　verified through practical and correct　there is no limit in 1970