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#include <time.h>
#include <posthaste/date.h>
ph_date_t date_from_string(const char str[static 11])
{
unsigned year = (str[0] - '0') * 1000
+ (str[1] - '0') * 100
+ (str[2] - '0') * 10
+ (str[3] - '0');
unsigned month = (str[5] - '0') * 10
+ (str[6] - '0');
unsigned day = (str[8] - '0') * 10
+ (str[9] - '0');
return date_from_numbers(year, month, day);
}
ph_date_t date_from_numbers(unsigned year, unsigned month, unsigned day)
{
return year << 9 | month << 5 | day;
}
struct tm tm_from_date(ph_date_t date)
{
unsigned year = 0;
unsigned month = 0;
unsigned day = 0;
date_split(date, &year, &month, &day);
struct tm time = {.tm_year = year - 1900, .tm_mon = month - 1,
.tm_mday = day};
mktime(&time);
return time;
}
ph_date_t date_from_tm(struct tm time)
{
unsigned year = time.tm_year + 1900;
unsigned month = time.tm_mon + 1;
unsigned day = time.tm_mday;
return date_from_numbers(year, month, day);
}
ph_date_t current_date()
{
time_t t = time(NULL);
struct tm *time = localtime(&t);
unsigned year = time->tm_year + 1900;
unsigned month = time->tm_mon + 1;
unsigned day = time->tm_mday;
return date_from_numbers(year, month, day);
}
void date_split(ph_date_t date, unsigned *year, unsigned *month, unsigned *day)
{
if (year) *year = date >> 9;
if (month) *month = (date >> 5) & 0xf;
if (day) *day = date & 0x1f;
}
void date_to_string(char str[static 11], ph_date_t date)
{
unsigned year, month, day;
date_split(date, &year, &month, &day);
str[0] = '0' + (year / 1000) % 10;
str[1] = '0' + (year / 100) % 10;
str[2] = '0' + (year / 10) % 10;
str[3] = '0' + year % 10;
str[4] = '-';
str[5] = '0' + (month / 10) % 10;
str[6] = '0' + month % 10;
str[7] = '-';
str[8] = '0' + (day / 10) % 10;
str[9] = '0' + day % 10;
str[10] = '\0';
}
bool date_valid(ph_date_t date)
{
unsigned year, month, day;
date_split(date, &year, &month, &day);
struct tm tm = {0};
tm.tm_year = year;
/* goddammit */
tm.tm_mon = month - 1;
tm.tm_mday = day;
time_t r = mktime(&tm);
/* if mktime fails to represent our time, it returns -1. mktime somewhat
* curiously accepts dates outside regular ranges, like negative time,
* but adjusts the tm structure to be 'correct', so we can check if any
* of the times were modified to see if this is a valid time. */
if (r == -1 || (int)year != tm.tm_year
|| (int)month != tm.tm_mon + 1|| (int)day != tm.tm_mday)
return false;
return true;
}
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