1 files changed, 77 insertions, 0 deletions
diff --git a/system.old/libraries/datetime/time.zig b/system.old/libraries/datetime/time.zig
new file mode 100644
index 0000000..9634ace
--- /dev/null
+++ b/system.old/libraries/datetime/time.zig
@@ -0,0 +1,77 @@
+//! Time operations
+
+const sys = @import("sys");
+const types = @import("types.zig");
+
+const ERROR_RESULT: u64 = @bitCast(@as(i64, -1));
+
+const SECONDS_PER_DAY: u64 = 86400;
+const SECONDS_PER_HOUR: u64 = 3600;
+const SECONDS_PER_MINUTE: u64 = 60;
+const DAYS_PER_4_YEARS: u64 = 1461;
+
+const DAYS_NORMAL = [_]u64{ 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 };
+const DAYS_LEAP = [_]u64{ 31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 };
+
+pub fn now() ?u64 {
+    const result = sys.syscall(.gettime, .{});
+
+    if (result == ERROR_RESULT) {
+        return null;
+    }
+
+    return result;
+}
+
+pub fn parts(timestamp: u64) types.DateTime {
+    const days_since_epoch = timestamp / SECONDS_PER_DAY;
+    const seconds_today = timestamp % SECONDS_PER_DAY;
+    const hours = seconds_today / SECONDS_PER_HOUR;
+    const minutes = (seconds_today % SECONDS_PER_HOUR) / SECONDS_PER_MINUTE;
+    const seconds = seconds_today % SECONDS_PER_MINUTE;
+
+    var year: u64 = 1970;
+    var remaining_days = days_since_epoch;
+
+    const four_year_cycles = remaining_days / DAYS_PER_4_YEARS;
+    year += four_year_cycles * 4;
+    remaining_days = remaining_days % DAYS_PER_4_YEARS;
+
+    while (remaining_days >= 365) {
+        const is_leap = isLeapYear(year);
+        const days_this_year: u64 = if (is_leap) 366 else 365;
+        if (remaining_days >= days_this_year) {
+            remaining_days -= days_this_year;
+            year += 1;
+        } else {
+            break;
+        }
+    }
+
+    const is_leap = isLeapYear(year);
+    const days_in_months = if (is_leap) DAYS_LEAP else DAYS_NORMAL;
+
+    var month: u8 = 1;
+    var day: u64 = remaining_days + 1;
+
+    for (days_in_months, 0..) |days, m| {
+        if (day <= days) {
+            month = @intCast(m + 1);
+            break;
+        }
+        day -= days;
+    }
+
+    return types.DateTime{
+        .year = year,
+        .month = month,
+        .day = @intCast(day),
+        .hour = @intCast(hours),
+        .minute = @intCast(minutes),
+        .second = @intCast(seconds),
+    };
+}
+
+fn isLeapYear(year: u64) bool {
+    return (year % 4 == 0 and year % 100 != 0) or (year % 400 == 0);
+}