LibC: Implement strftime()
I did not test this at all, this might very well be broken
This commit is contained in:
parent
1d9041f2aa
commit
5dce4e6aea
|
|
@ -1,6 +1,8 @@
|
|||
#include <BAN/Assert.h>
|
||||
#include <BAN/Debug.h>
|
||||
#include <BAN/Math.h>
|
||||
|
||||
#include <ctype.h>
|
||||
#include <string.h>
|
||||
#include <sys/syscall.h>
|
||||
#include <time.h>
|
||||
#include <unistd.h>
|
||||
|
|
@ -107,6 +109,346 @@ struct tm* localtime(const time_t* timer)
|
|||
|
||||
size_t strftime(char* __restrict s, size_t maxsize, const char* __restrict format, const struct tm* __restrict timeptr)
|
||||
{
|
||||
dwarnln("strftime({}, {}, {}, {})", s, maxsize, format, timeptr);
|
||||
ASSERT_NOT_REACHED();
|
||||
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;
|
||||
}
|
||||
|
|
|
|||
Loading…
Reference in New Issue