聊聊时间（2）硬核算法篇——UNIX时间戳转UTC时间

#include <stdio.h>#include "timex_test1.h"utc_t UtcTime;int main(void) { int retVal; int u32UnixTimeStamp = 0; int hour, minute, sec; printf("input the UNIX time stamp:"); scanf("%d", &u32UnixTimeStamp); if(u32UnixTimeStamp >= 86400)  { printf("input out of range!\n"); retVal = 1; } else  { hour = u32UnixTimeStamp / 3600; //计算小时 minute = (u32UnixTimeStamp - hour * 3600) / 60; //计算分 sec = (u32UnixTimeStamp - hour * 3600 - minute * 60); //计算秒 UtcTime.year = 1970; UtcTime.month = 1; UtcTime.date = 1; UtcTime.hour = 0 + hour; UtcTime.minute = 0 + minute; UtcTime.second = 0 + sec; printf("\nUTC time is : %dy - %dm - %dd\n", UtcTime.year, UtcTime.month, UtcTime.date); printf("\nUTC time is : %dh - %dm : %ds\n", UtcTime.hour, UtcTime.minute, UtcTime.second); retVal = 0; } return retVal;}

#ifndef __TIMEX_H_#define __TIMEX_H_
/*定义UTC时间结构体类型*/typedef struct { int year; int month; int date; int hour; int minute; int second;} utc_t;
#endif

#include <stdio.h>#include "timex_test2.h"utc_t UtcTime;int main(void) { int retVal; int u32UnixTimeStamp = 0; int hour, minute, sec; int flat_year_month_day[13] = {0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31}; int leap_year_month_day[13] = {0, 31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31}; int year_temp = 0; int day_temp = 0; unsigned int cnt_temp = 0; int is_leap_or_flat_year; int i; printf("input the UNIX time stamp:"); scanf("%d", &u32UnixTimeStamp);
 cnt_temp = u32UnixTimeStamp; /*判断当前UNIX时间戳经过了多少个4年*/ while(cnt_temp >= 126230400) { year_temp ++; cnt_temp = cnt_temp - 126230400; } /*计算出当前的4年周期起始年份*/ UtcTime.year = UNIX_TIME_YEAR + (4 * year_temp);  /*计算出当前的年份*/  /*这部分代码可使用循环做精简，为了直观，我将其写开*/ if(cnt_temp >= 31536000) { UtcTime.year ++; cnt_temp -= 31536000; /*Flat year*/ if(cnt_temp >= 31536000) { UtcTime.year ++; cnt_temp -= 31536000; /*Leap year*/ if(cnt_temp >= 31622400) { UtcTime.year ++; cnt_temp -= 31622400; /*Flat year*/ if(cnt_temp >= 31536000) { UtcTime.year ++; cnt_temp -= 31536000; }  } } }
 /*计算当前年份是平年还是闰年*/ if((((UtcTime.year % 4) == 0) && ((UtcTime.year % 100) != 0)) || ((UtcTime.year % 400) == 0))  { is_leap_or_flat_year = LEAP_YEAR; } else { is_leap_or_flat_year = FLAT_YEAR; }  /*计算出不足一年剩余的天数*/ day_temp = cnt_temp / 86400;
 /*剩余不足86400s的时间戳，计算出时间*/ UtcTime.hour = (cnt_temp - day_temp * 86400) / 3600; //Calculate hours UtcTime.minute = (cnt_temp - day_temp * 86400 - UtcTime.hour * 3600) / 60; //Calculate minutes UtcTime.second = cnt_temp % 60; 
 /*将天数结合平年还是闰年查表计算出当前的月份*/ UtcTime.month = 1; for(i = 0; i < 12; i ++) { if(is_leap_or_flat_year == FLAT_YEAR) { if(day_temp >= flat_year_month_day[i + 1]) { UtcTime.month ++; day_temp -= flat_year_month_day[i + 1]; } }  else if(is_leap_or_flat_year == LEAP_YEAR) { if(day_temp >= leap_year_month_day[i + 1]) { UtcTime.month ++; day_temp -= leap_year_month_day[i + 1]; } }  }
 /*由于天数从1开始，因此需要加1*/
 UtcTime.date = day_temp + 1;
 printf("\nTime transform successfully\n"); printf("++++++++++++++++++++++++++++++++++\n"); printf("\nUTC time is : %dy - %dm - %dd\n", UtcTime.year, UtcTime.month, UtcTime.date); printf("\nUTC time is : %dh - %dm : %ds\n", UtcTime.hour, UtcTime.minute, UtcTime.second); printf("++++++++++++++++++++++++++++++++++\n"); printf("\n"); printf("\n"); return 0;}

#ifndef __TIMEX_H_#define __TIMEX_H_
/*定义UTC时间结构体类型*/typedef struct { int year; int month; int date; int hour; int minute; int second;} utc_t;
/*定义UNIX时间戳的起始UNIX时间*/#define UNIX_TIME_YEAR 1970#define UNIX_TIME_MONTH 1#define UNIX_TIME_DATE 1#define UNIX_TIME_HOUR 0#define UNIX_TIME_MINIUTE 0#define UNIX_TIME_SECOND 0#define LEAP_YEAR 1#define FLAT_YEAR 0
#endif