banan-os/userspace/libraries/LibC/time.cpp

470 lines
10 KiB
C++

#include <BAN/Debug.h>
#include <BAN/Math.h>
#include <ctype.h>
#include <string.h>
#include <sys/syscall.h>
#include <time.h>
#include <unistd.h>
// sample implementation from https://pubs.opengroup.org/onlinepubs/9699919799/functions/asctime.html
char* asctime(const struct tm* timeptr)
{
static constexpr char wday_name[][4] {
"Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"
};
static constexpr char mon_name[][4] {
"Jan", "Feb", "Mar", "Apr", "May", "Jun",
"Jul", "Aug", "Sep", "Oct", "Nov", "Dec"
};
static char result[128];
sprintf(result, "%.3s %.3s%3d %.2d:%.2d:%.2d %d\n",
wday_name[timeptr->tm_wday],
mon_name[timeptr->tm_mon],
timeptr->tm_mday, timeptr->tm_hour,
timeptr->tm_min, timeptr->tm_sec,
1900 + timeptr->tm_year);
return result;
}
int clock_gettime(clockid_t clock_id, struct timespec* tp)
{
return syscall(SYS_CLOCK_GETTIME, clock_id, tp);
}
char* ctime(const time_t* clock)
{
return asctime(localtime(clock));
}
int nanosleep(const struct timespec* rqtp, struct timespec* rmtp)
{
return syscall(SYS_NANOSLEEP, rqtp, rmtp);
}
time_t time(time_t* tloc)
{
timespec tp;
if (clock_gettime(CLOCK_REALTIME, &tp) == -1)
return -1;
if (tloc)
*tloc = tp.tv_sec;
return tp.tv_sec;
}
struct tm* gmtime(const time_t* timer)
{
static struct tm tm;
constexpr auto is_leap_year =
[](time_t year) -> bool
{
if (year % 400 == 0)
return true;
if (year % 100 == 0)
return false;
if (year % 4 == 0)
return true;
return false;
};
constexpr uint64_t month_days[] { 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334, 365 };
time_t time = *timer;
tm.tm_sec = time % 60; time /= 60;
tm.tm_min = time % 60; time /= 60;
tm.tm_hour = time % 24; time /= 24;
time_t total_days = time;
tm.tm_wday = (total_days + 4) % 7;
tm.tm_year = 1970;
while (total_days >= 365U + is_leap_year(tm.tm_year))
{
total_days -= 365U + is_leap_year(tm.tm_year);
tm.tm_year++;
}
bool is_leap_day = is_leap_year(tm.tm_year) && total_days == month_days[2];
bool had_leap_day = is_leap_year(tm.tm_year) && total_days > month_days[2];
for (tm.tm_mon = 0; tm.tm_mon < 12; tm.tm_mon++)
if (total_days < month_days[tm.tm_mon + 1] + (is_leap_day || had_leap_day))
break;
tm.tm_mday = total_days - month_days[tm.tm_mon] + !had_leap_day;
tm.tm_yday = total_days;
tm.tm_year -= 1900;
tm.tm_isdst = 0;
return &tm;
}
struct tm* localtime(const time_t* timer)
{
// FIXME: support timezones
return gmtime(timer);
}
size_t strftime(char* __restrict s, size_t maxsize, const char* __restrict format, const struct tm* __restrict timeptr)
{
size_t len = 0;
struct conversion_t
{
char flag = '\0';
int width = -1;
char modifier = '\0';
};
static constexpr const char* abbr_wday[] {
"Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"
};
static constexpr const char* full_wday[] {
"Sunday", "Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday"
};
static constexpr const char* abbr_mon[] {
"Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"
};
static constexpr const char* full_mon[] {
"January", "February", "March", "April", "May", "June", "July", "August", "September", "October", "November", "December"
};
const auto append_string =
[&](const char* string) -> bool
{
size_t string_len = strlen(string);
if (len + string_len >= maxsize)
return false;
strcpy(s + len, string);
len += string_len;
return true;
};
const auto append_string_from_list =
[&]<size_t LIST_SIZE>(int index, const char* const (&list)[LIST_SIZE]) -> bool
{
const char* string = "INVALID";
if (index >= 0 && index < (int)LIST_SIZE)
string = list[index];
return append_string(string);
};
const auto append_value =
[&](const char* format, int value) -> bool
{
int written = snprintf(s + len, maxsize - len, format, value);
if (len + written >= maxsize)
return false;
len += written;
return true;
};
while (*format && len < maxsize)
{
if (*format != '%')
{
s[len++] = *format++;
continue;
}
format++;
conversion_t conversion;
switch (*format)
{
case '+':
case '0':
conversion.flag = *format;
format++;
break;
}
if (isdigit(*format))
{
conversion.width = 0;
while (isdigit(*format))
{
conversion.width = (conversion.width * 10) + (*format + '0');
format++;
}
}
switch (*format)
{
case 'E':
case 'O':
dwarnln("TODO: strftime moodifiers");
conversion.modifier = *format;
format++;
break;
}
switch (*format)
{
case 'a':
if (!append_string_from_list(timeptr->tm_wday, abbr_wday))
return 0;
break;
case 'A':
if (!append_string_from_list(timeptr->tm_wday, full_wday))
return 0;
break;
case 'b':
case 'h':
if (!append_string_from_list(timeptr->tm_mon, abbr_mon))
return 0;
break;
case 'B':
if (!append_string_from_list(timeptr->tm_mon, full_mon))
return 0;
break;
case 'c':
if (size_t ret = strftime(s + len, maxsize - len, "%a %b %e %H:%M:%S %Y", timeptr))
len += ret;
else return 0;
break;
case 'C':
{
if (conversion.flag == '\0')
conversion.flag = ' ';
if (conversion.flag == '+' && conversion.width <= 2)
conversion.flag = '0';
if (conversion.width < 2)
conversion.width = 2;
char new_format[32];
sprintf(new_format, "%%%c%dd", conversion.flag, conversion.width);
if (!append_value(new_format, timeptr->tm_year % 100))
return 0;
break;
}
case 'd':
if (!append_value("%02d", timeptr->tm_mday))
return 0;
break;
case 'D':
if (size_t ret = strftime(s + len, maxsize - len, "%m/%d/%y", timeptr))
len += ret;
else return 0;
break;
case 'e':
if (!append_value("% 2d", timeptr->tm_mday))
return 0;
break;
case 'F':
{
if (conversion.flag == '\0')
conversion.flag = '+';
if (conversion.width == -1)
conversion.width = 10;
if (conversion.width < 6)
conversion.width = 6;
char new_format[32];
sprintf(new_format, "%%%c%dY-%%m-%%d", conversion.flag, conversion.width - 6);
if (size_t ret = strftime(s + len, maxsize - len, new_format, timeptr))
len += ret;
else return 0;
break;
}
case 'H':
if (!append_value("%02d", timeptr->tm_hour))
return 0;
break;
case 'I':
if (!append_value("%02d", ((timeptr->tm_hour + 11) % 12) + 1))
return 0;
break;
case 'j':
if (!append_value("%03d", timeptr->tm_yday + 1))
return 0;
break;
case 'm':
if (!append_value("%02d", timeptr->tm_mon + 1))
return 0;
break;
case 'M':
if (!append_value("%02d", timeptr->tm_min))
return 0;
break;
case 'n':
s[len++] = '\n';
break;
case 'p':
if (!append_string(timeptr->tm_hour < 12 ? "AM" : "PM"))
return 0;
break;
case 'r':
if (size_t ret = strftime(s + len, maxsize - len, "%I:%M:%S %p", timeptr))
len += ret;
else return 0;
break;
case 'R':
if (size_t ret = strftime(s + len, maxsize - len, "%H:%M", timeptr))
len += ret;
else return 0;
break;
case 'S':
if (!append_value("%02d", timeptr->tm_sec))
return 0;
break;
case 't':
s[len++] = '\t';
break;
case 'T':
if (size_t ret = strftime(s + len, maxsize - len, "%H:%M:%S", timeptr))
len += ret;
else return 0;
break;
case 'u':
if (!append_value("%d", ((timeptr->tm_wday + 6) % 7) + 1))
return 0;
break;
case 'U':
if (!append_value("%02d", (timeptr->tm_yday - timeptr->tm_wday + 7) / 7))
return 0;
break;
case 'g':
case 'G':
case 'V':
{
// Adapted from GNU libc implementation
constexpr auto is_leap_year =
[](int year) -> bool
{
if (year % 400 == 0)
return true;
if (year % 100 == 0)
return false;
if (year % 4 == 0)
return true;
return false;
};
constexpr auto iso_week_days =
[](int yday, int wday) -> int
{
return yday - (wday + 382) % 7 + 3;
};
int year = timeptr->tm_year + 1900;
int days = iso_week_days(timeptr->tm_yday, timeptr->tm_wday);
if (days < 0)
{
year--;
days = iso_week_days(timeptr->tm_yday + (365 + is_leap_year(year)), timeptr->tm_wday);
}
else
{
int d = iso_week_days(timeptr->tm_yday - (365 + is_leap_year(year)), timeptr->tm_wday);
if (d >= 0)
{
year++;
days = d;
}
}
switch (*format)
{
case 'g':
if (!append_value("%02d", ((year % 100) + 100) % 100))
return 0;
break;
case 'G':
{
if (conversion.flag == '\0')
conversion.flag = ' ';
if (conversion.flag == '+' && conversion.width <= 4)
conversion.flag = '0';
if (conversion.width == -1)
conversion.width = 0;
char new_format[32];
sprintf(new_format, "%%%c%dd", conversion.flag, conversion.width);
if (!append_value(new_format, year))
return 0;
break;
}
case 'V':
if (!append_value("%02d", days / 7 + 1))
return 0;
break;
}
break;
}
case 'w':
if (!append_value("%d", timeptr->tm_wday))
return 0;
break;
case 'W':
if (!append_value("%02d", (timeptr->tm_yday - (timeptr->tm_wday - 1 + 7) % 7 + 7) / 7))
return 0;
break;
case 'x':
if (size_t ret = strftime(s + len, maxsize - len, "%m/%d/%y", timeptr))
len += ret;
else return 0;
break;
case 'X':
if (size_t ret = strftime(s + len, maxsize - len, "%H:%M:%S", timeptr))
len += ret;
else return 0;
break;
case 'y':
if (!append_value("%d", timeptr->tm_yday % 100))
return 0;
break;
case 'Y':
{
if (conversion.flag == '\0')
conversion.flag = ' ';
if (conversion.flag == '+' && conversion.width <= 4)
conversion.flag = '0';
if (conversion.width == -1)
conversion.width = 0;
char new_format[32];
sprintf(new_format, "%%%c%dd", conversion.flag, conversion.width);
if (!append_value(new_format, 1900 + timeptr->tm_year))
return 0;
break;
}
case 'z':
// FIXME: support timezones
break;
case 'Z':
// FIXME: support timezones
break;
case '%':
s[len++] = '%';
break;
}
format++;
}
if (*format != '\0')
return 0;
s[len++] = '\0';
return len;
}
#include <BAN/Assert.h>
long timezone;
void tzset()
{
ASSERT_NOT_REACHED();
}
time_t mktime(struct tm*)
{
ASSERT_NOT_REACHED();
}