8位单片机可用的 mktime localtime函数

8位单片机可用的 mktime localtime函数及源码

最近在做一个8位单片机项目，其中用到了时间戳转换函数，这个在32位机上一个库函数就解决了问题，没想到在8位单片机中没有对应库（time.h），没有办法只有自己来写。

目标：1，满足和库函数mktime localtime所计算出的数据一至；2，考虑8位单片机的处理能力慢软件效率问题。

分享给大家，方便有同样需求的朋友。

gcc 环境进行测试：

测试程序：

 #include <stdio.h>

 #include <stdint.h>

 #include <time.h>

 #include <string.h>

 #if 0

 struct tm {

     int tm_sec;   /* seconds after the minute, 0 to 60

                      (0 - 60 allows for the occasional leap second) */

     int tm_min;   /* minutes after the hour, 0 to 59 */

     int tm_hour;  /* hours since midnight, 0 to 23 */

     int tm_mday;  /* day of the month, 1 to 31 */

     int tm_mon;   /* months since January, 0 to 11 */

     int tm_year;  /* years since 1900 */

 //    int tm_wday;  /* days since Sunday, 0 to 6 */

 //    int tm_yday;  /* days since January 1, 0 to 365 */

 //    int tm_isdst; /* Daylight Savings Time flag */

 };

 #endif

 static const char mon_list[]             = {, , , , , , , , , , , };

 static const char leap_mon_list[]        = {, , , , , , , , , , , };

 /*******************************************************************************

 * Function Name : fun_mktime

 * Description   : 时间转为时间戳

 * Input         :

 * Output        :

 * Other         :

 * Date          : 2016.11.14

 *******************************************************************************/

 int32_t fun_mktime(struct tm *pT)

 {

     const char *pDays = NULL;

     int32_t tmp = ;

     int16_t i = ;

     //计算总共有多少个闰年

     tmp = (pT->tm_year  /  - pT->tm_year /  + pT->tm_year / ) - ( /  -  /  +  / );

     //如果当年是闰年，需要减去当年的闰年

     if ((pT->tm_year %  == ) && ((pT->tm_year  %  != ) || (pT->tm_year  %  == )))

     {

         tmp = tmp -  + (pT->tm_year - ) * ;

         pDays = leap_mon_list;

     }

     else

     {

         tmp = tmp + (pT->tm_year - ) * ;

         pDays = mon_list;

     }

     for (i = ; i < pT->tm_mon - ; i++)

         tmp += pDays[i];

     tmp = tmp + pT->tm_mday - ;

     tmp = tmp *  + pT->tm_hour;

     tmp = tmp *  + pT->tm_min;

     tmp = tmp *  + pT->tm_sec;

     return tmp;

 }

 /*******************************************************************************

 * Function Name : fun_localtime

 * Description   : 时间戳转为时间

 * Input         :   struct tm *pT： 输出的时间缓冲区   uint32_t tim:当前时间戳

 * Output        :

 * Other         :

 * Date          : 2016.11.14

 *******************************************************************************/

 void fun_localtime(struct tm *pT, int32_t tim)

 {

   const char *pDays = NULL;

   uint16_t index = ;

   memset(pT, , sizeof(*pT));

   //year initialization

   if (tim > 0x5685C180L)            // 2016-1-1 0:0:0

   {

     pT->tm_year = ;

     tim -= 0x5685C180L;

   }

   else if (tim > 0x4B3D3B00L)       // 2010-1-1 0:0:0

   {

     pT->tm_year = ;

     tim -= 0x4B3D3B00L;

   }

   else if (tim > 0x386D4380L)       // 2000-1-1 0:0:0

   {

     pT->tm_year = ;

     tim -= 0x386D4380L;

   }

   else

   {

     pT->tm_year = ;

   }

   //now have year

   while (tim >= 366L *  *  * )

   {

     if ((pT->tm_year %  == ) && ((pT->tm_year  %  != ) || (pT->tm_year  %  == )))

       tim -= 366L *  *  * ;

     else

       tim -= 365L *  *  * ;

     pT->tm_year++;

   }

   // then 365 * 24 * 60 * 60 < tim < 366 * 24 * 60 * 60

   if (!(((pT->tm_year %  == ) && ((pT->tm_year  %  != ) || (pT->tm_year  %  == ))))

     && (tim > 365L *  *  * ))

   {

     tim -= 365L *  *  * ;

     pT->tm_year++;

   }

   // this year is a leap year?

   if (((pT->tm_year %  == ) && ((pT->tm_year  %  != ) || (pT->tm_year  %  == ))))

     pDays = leap_mon_list;

   else

     pDays = mon_list;

   pT->tm_mon = ;

   // now have mon

   while (tim > pDays[index] * 24L *  * )

   {

     tim -= pDays[index] * 24L *  * ;

     index++;

     pT->tm_mon++;

   }

   // now have days

   pT->tm_mday = tim / (24L *  * ) + ;

   tim = tim % (24L *  * );

   // now have hour

   pT->tm_hour = tim / ( * );

   tim = tim % ( * );

   // now have min

   pT->tm_min = tim / ;

   tim = tim % ;

   pT->tm_sec = tim;

 }

 int main (void *parg)

 {

   struct tm *pT = {};

   time_t timep = ;

   uint32_t cur_tim = ;

   time(&timep);

   pT = localtime(&timep);

   printf("linux time \t= %d\n", (int32_t)timep);

   pT->tm_year += ;

   pT->tm_mon += ;

   printf("fun_mktime \t= %d\n", cur_tim = (uint32_t)fun_mktime(pT));

   printf("localtime \t= %d-%d-%d %d:%d:%d\n", pT->tm_year, pT->tm_mon, pT->tm_mday, pT->tm_hour, pT->tm_min, pT->tm_sec);

   memset(pT, , sizeof(*pT));

   fun_localtime(pT, cur_tim);

   printf("fun_localtime \t= %d-%d-%d %d:%d:%d\n", pT->tm_year, pT->tm_mon, pT->tm_mday, pT->tm_hour, pT->tm_min, pT->tm_sec);

   return ;

 }

测试结果：

linux time      =

fun_mktime      =

localtime       = -- ::

fun_localtime   = -- ::

linux time 是库函数mktime计算结果，因为进行了时区处理，所以与fun_mktime计算出来刚好是8 * 3600 秒的差值

此函数在C51下进行过测试，符合要求。

巴特西

8位单片机可用的 mktime localtime函数

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