最近使用GPS模块获取解析GPRMC数据的时候,获取到的是UTC时间,需要转换为北京时间,网上看了一些文章,发现存在一些问题,于是自己完善了一下,并做了注释,方便理解。
typedef struct
{
uint16_t year; //年份
uint8_t month; //月份
uint8_t date; //日期
uint8_t hour; //小时
uint8_t min; //分钟
uint8_t sec; //秒钟
}*p_nmea_time, s_nmea_time;
//UTC时间转换为任意时区时间,如果是转换为北京时间,timezone传8即可
static void utc_to_local_time(p_nmea_time utc_time, int8_t timezone, p_nmea_time local_time)
{
int year,month,day,hour;
int lastday = 0; //last day of this month 本月天数
int lastlastday = 0; //last day of last month 上个月天数
year = utc_time->year; //utc time
month = utc_time->month;
day = utc_time->date;
hour = utc_time->hour + timezone;
//1月大,2月小,3月大,4月小,5月大,6月小,7月大,8月大,9月小,10月大,11月小,12月大
if(month==1 || month==3 || month==5 || month==7 || month==8 || month==10 || month==12)
{
lastday = 31;//本月天数
lastlastday = 30;//这里应该补上上个月的天数
if(month == 3)
{
if((year%400 == 0)||(year%4 == 0 && year%100 != 0))//if this is lunar year
lastlastday = 29;
else
lastlastday = 28;
}
if(month == 8 || month == 1)//这里应该是8月和1月,因为8月和1月的上一个月(7月和12月)的天数是31天的
lastlastday = 31;
}
else if(month == 4 || month == 6 || month == 9 || month == 11)
{
lastday = 30;
lastlastday = 31;
}
else
{
lastlastday = 31;
if((year%400 == 0)||(year%4 == 0 && year%100 != 0))
lastday = 29;
else
lastday = 28;
}
if(hour >= 24)// if >24, day+1
{
hour -= 24;
day += 1;
if(day > lastday)// next month, day-lastday of this month
{
day -= lastday;
month += 1;
if(month > 12)// next year, month-12
{
month -= 12;
year += 1;
}
}
}
if(hour < 0)// if <0, day-1
{
hour += 24;
day -= 1;
if(day < 1)// month-1, day=last day of last month
{
day = lastlastday;
month -= 1;
if(month < 1)// last year, month=12
{
month = 12;
year -= 1;
}
}
}
// transfer value to local_time
local_time->year = year;
local_time->month = month;
local_time->date = day;
local_time->hour = hour;
local_time->min = utc_time->min;
local_time->sec = utc_time->sec;
}
http://www.360doc.com/content/20/0810/08/18945873_929440823.shtml