75 lines
2.5 KiB
C++
75 lines
2.5 KiB
C++
|
/* Copyright Manx Software Systems 1989. All rights reserved */
|
||
|
|
|
||
|
|
/*
|
||
|
|
* time_t mktime(struct tm *timeptr)
|
||
|
|
*
|
||
|
|
* converts the broken-down time, expressed as local time, in the
|
||
|
|
* structure pointed to by timeptr into a calendar time value with
|
||
|
|
* the same encoding as that of the values returned by the time
|
||
|
|
* function. The original values of the tm_wday and tm_yday
|
||
|
|
* components of the structure are ignored, and the original values
|
||
|
|
* of the other components are not restricted to the ranges
|
||
|
|
* specified for the tm structure. On successful completion, the
|
||
|
|
* values of the tm_wday and tm_yday components of the structure are
|
||
|
|
* set appropriately, and the other components are set to represent
|
||
|
|
* the specified calendar time, but with their values forced to the
|
||
|
|
* ranges indicated for the tm structure; the final value of tm_mday
|
||
|
|
* is not set until tm_mon and tm_year are determined.
|
||
|
|
*
|
||
|
|
* returns the specified calendar time encoded as a value of type
|
||
|
|
* time_t. If the calendar time cannot be represented, the function
|
||
|
|
* returns the value (time_t)-1.
|
||
|
|
*/
|
||
|
|
|
||
|
|
#include <time.h>
|
||
|
|
|
||
|
|
#define SECS_IN_DAY (60*60*24L)
|
||
|
|
#define YEARS_IN_GOOGLE 4 /* google is a 4 year period including leap year */
|
||
|
|
#define DAYS_IN_GOOGLE (4*365L+1)
|
||
|
|
#define SECS_IN_MIN 60
|
||
|
|
#define MIN_IN_HOUR 60
|
||
|
|
#define HOURS_IN_DAY 24
|
||
|
|
#define SECS_IN_HOUR (60*60L)
|
||
|
|
|
||
|
|
time_t mktime(struct tm *timeptr)
|
||
|
|
{
|
||
|
|
register int i, ry, ydays, year_day, years, googles;
|
||
|
|
time_t ltime;
|
||
|
|
static int days[12]={ 31,28,31,30,31,30,31,31,30,31,30,31 };
|
||
|
|
|
||
|
|
if (timeptr->tm_sec < 0 || timeptr->tm_min < 0 ||
|
||
|
|
timeptr->tm_hour < 0 || timeptr->tm_mday < 0 ||
|
||
|
|
timeptr->tm_mon < 0 || timeptr->tm_year < 70)
|
||
|
|
return(-1);
|
||
|
|
|
||
|
|
ltime = timeptr->tm_sec;
|
||
|
|
ltime += SECS_IN_MIN * timeptr->tm_min;
|
||
|
|
ltime += SECS_IN_HOUR * timeptr->tm_hour;
|
||
|
|
ltime += SECS_IN_DAY * (timeptr->tm_mday - 1);
|
||
|
|
|
||
|
|
/* calculate the number of days already past in the current year */
|
||
|
|
|
||
|
|
for (i=0,year_day=0;i<timeptr->tm_mon;i++) {
|
||
|
|
year_day += days[i];
|
||
|
|
if (i==1 && (timeptr->tm_year & 3) == 0)
|
||
|
|
year_day++;
|
||
|
|
}
|
||
|
|
ltime += year_day * SECS_IN_DAY;
|
||
|
|
years = timeptr->tm_year - 70;
|
||
|
|
googles = years / YEARS_IN_GOOGLE; /* number of googles since 1970 */
|
||
|
|
ltime+= googles * DAYS_IN_GOOGLE * SECS_IN_DAY;
|
||
|
|
ry= 70 + YEARS_IN_GOOGLE * googles;
|
||
|
|
|
||
|
|
/* calculate number of days since last google */
|
||
|
|
|
||
|
|
for (i=ry, ydays=0; i < timeptr->tm_year; i++) {
|
||
|
|
ydays += 365;
|
||
|
|
if ((i & 3) == 0)
|
||
|
|
ydays++;
|
||
|
|
}
|
||
|
|
ltime += ydays * SECS_IN_DAY;
|
||
|
|
*timeptr = *localtime(<ime);
|
||
|
|
return(ltime);
|
||
|
|
}
|
||
|
|
|