timestamp 与日期时间互转的 C 语言实现

#include <stdlib.h> #include <stdint.h> #include "datetime.h" static const unsigned int max_days_in_month[] = { 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31, }; static const unsigned int days_of_months_in_common_year[] = { 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334, 365, }; static const unsigned int days_of_months_in_leap_year[] = { 0, 31, 60, 91, 121, 152, 182, 213, 244, 274, 305, 335, 366, }; static int ____total_leap_years_from2000(unsigned int year) { register unsigned int elasped_years; register unsigned int elasped_leap_years; if (year < 2000) return -1; elasped_years = year - 1 - 2000; elasped_leap_years = elasped_years / 4; elasped_leap_years -= elasped_years / 100; elasped_leap_years += elasped_years / 400; if (elasped_years) elasped_leap_years += 1; return elasped_leap_years; } static int __total_leap_years(unsigned int year) { register unsigned int elasped_leap_years; if (year < 1970) { return -1; } if (year <= 1972) { elasped_leap_years = 0; } else if (year <= 2000) { elasped_leap_years = (year - 1 - 1972) / 4 + 1; } else { elasped_leap_years = (2000 - 1 - 1972) / 4 + 1; elasped_leap_years += ____total_leap_years_from2000(year); } return elasped_leap_years; } static int ____total_days_in_common_year(unsigned int month, unsigned int day) { if ((month < 1) || (month > 12)) return -1; if (day > max_days_in_month[month - 1]) return -1; return (days_of_months_in_common_year[month - 1] + day - 1); } static __inline__ int __is_leap_year(unsigned int year) { if ((year % 4) == 0) { if (((year % 100) == 0) && ((year % 400) != 0)) return 0; return 1; } return 0; } static int __total_days(unsigned int year, unsigned int month, unsigned int day) { int leap_years; int days_in_year; leap_years = __total_leap_years(year); if (leap_years == -1) return -1; days_in_year = ____total_days_in_common_year(month, day); if (days_in_year == -1) return -1; if ((month > 2) && __is_leap_year(year)) days_in_year += 1; return (leap_years * 366 + (year - 1970 - leap_years) * 365 + days_in_year); } static int __year_after_days(unsigned int days) { register unsigned int year; year = 1970 + days / 365; while (1) { if (__total_days(year, 1, 1) > (int)days) year -= 1; else break; } return year; } static int __days_after_month_in_common_year(unsigned int days, unsigned int left, unsigned int right) { register unsigned int middle; middle = (left + right) / 2; if (days < days_of_months_in_common_year[middle]) return __days_after_month_in_common_year(days, left, middle); else if (days >= days_of_months_in_common_year[middle + 1]) return __days_after_month_in_common_year(days, middle + 1, right); return (middle + 1); } static int ___days_after_month_in_leap_year(unsigned int days, unsigned int left, unsigned int right) { register unsigned int middle; middle = (left + right) / 2; if (days < days_of_months_in_leap_year[middle]) return ___days_after_month_in_leap_year(days, left, middle); else if (days >= days_of_months_in_leap_year[middle + 1]) return ___days_after_month_in_leap_year(days, middle + 1, right); return (middle + 1); } static int days_after_month_in_common_year(unsigned int days) { if (days >= 365) return -1; return __days_after_month_in_common_year(days, 0, 12); } static int __days_after_month_in_leap_year(unsigned int days) { if (days >= 366) return -1; return ___days_after_month_in_leap_year(days, 0, 12); } int total_years(struct date *date) { if (date == NULL) return -1; if (date->year < 1970) return -1; return (date->year - 1970); } int total_leap_years(struct date *date) { if (date == NULL) return -1; return __total_leap_years(date->year); } int total_months(struct date *date) { register int years; if (date == NULL) return -1; if ((date->month < 1) || (date->month > 12)) return -1; years = total_years(date); if (years == -1) return -1; return ((years * 12) + date->month - 1); } int total_days(struct date *date) { if (date == NULL) return -1; return __total_days(date->year, date->month, date->day); } int make_date(unsigned int days, struct date *date) { if (date == NULL) return -1; date->weekday = (((days % 7) + 3) % 7) + 1; date->year = __year_after_days(days); days -= __total_days(date->year, 1, 1); if (__is_leap_year(date->year)) { date->month = __days_after_month_in_leap_year(days); date->day = days - days_of_months_in_leap_year[date->month - 1] + 1; } else { date->month = days_after_month_in_common_year(days); date->day = days - days_of_months_in_common_year[date->month - 1] + 1; } return 0; } int day_of_year(struct date *date) { register int days; if (date == NULL) return -1; if (date->year < 1970) return -1; if ((date->month < 1) || (date->month > 12)) return -1; if (date->day < 1) return -1; if (__is_leap_year(date->year)) { if ((date->month == 2) && (date->day > 29)) return -1; else if (date->day > max_days_in_month[date->month - 1]) return -1; else days = days_of_months_in_leap_year[date->month - 1]; } else { if (date->day > max_days_in_month[date->month - 1]) return -1; else days = days_of_months_in_common_year[date->month - 1]; } return (days + date->day); } int day_of_week(struct date *date) { register int days; if (date == NULL) return -1; days = __total_days(date->year, date->month, date->day); if (days == -1) return -1; date->weekday = (((days % 7) + 3) % 7) + 1; return date->weekday; } int time_to_timestamp(struct time *time) { register int timestamp; if (time == NULL) { return -1; } if (time->hour > 23) { return -1; } if (time->minute > 59) { return -1; } if (time->second > 59) { return -1; } if (time->milling > 999) { return -1; } timestamp = time->hour * 60 * 60 * 1000; timestamp += time->minute * 60 * 1000; timestamp += time->second * 1000; timestamp += time->milling; return timestamp; } int make_time(uint64_t timestamp, struct time *time) { if (time == NULL) return -1; time->milling = timestamp % 1000; timestamp /= 1000; time->second = timestamp % 60; timestamp /= 60; time->minute = timestamp % 60; timestamp /= 60; time->hour = timestamp % 60; return 0; } int datetime_to_timestamp(struct datetime *datetime, uint64_t *timestamp) { register int days, timestamp_in_day; if (datetime == NULL) { return -1; } days = total_days(&datetime->date); if (days == -1) { return -1; } timestamp_in_day = time_to_timestamp(&datetime->time); if (timestamp_in_day == -1) { return -1; } if (timestamp != NULL) { *timestamp = (((uint64_t)days) * 24 * 60 * 60 * 1000) + timestamp_in_day; } return 0; }