Update time_rtc example to use `time` crate

ctru-rs/Cargo.toml

@@ -21,3 +21,4 @@ widestring = "0.2.2"
 
 [dev-dependencies]
 ferris-says = "0.2.1"
+time = "0.3.7"

ctru-rs/examples/time_rtc.rs

@@ -3,64 +3,6 @@ use ctru::gfx::Gfx;
 use ctru::services::apt::Apt;
 use ctru::services::hid::{Hid, KeyPad};
 
-const MONTHS: [&str; 12] = [
-    "January",
-    "February",
-    "March",
-    "April",
-    "May",
-    "June",
-    "July",
-    "August",
-    "September",
-    "October",
-    "November",
-    "December",
-];
-
-const WEEKDAYS: [&str; 7] = [
-    "Sunday",
-    "Monday",
-    "Tuesday",
-    "Wednesday",
-    "Thursday",
-    "Friday",
-    "Saturday",
-];
-
-const MONTH_TO_WEEKDAY_TABLE: [i32; 12] = [
-    0 % 7,   //january    31
-    31 % 7,  //february   28+1(leap year)
-    59 % 7,  //march      31
-    90 % 7,  //april      30
-    120 % 7, //may        31
-    151 % 7, //june       30
-    181 % 7, //july       31
-    212 % 7, //august     31
-    243 % 7, //september  30
-    273 % 7, //october    31
-    304 % 7, //november   30
-    334 % 7, //december   3
-];
-
-fn is_leap_year(year: i32) -> bool {
-    year % 4 == 0 && !(year % 100 == 0 && year % 400 != 0)
-}
-
-/// <http://en.wikipedia.org/wiki/Calculating_the_day_of_the_week>
-fn get_day_of_week(mut day: i32, month: usize, mut year: i32) -> usize {
-    day += 2 * (3 - ((year / 100) % 4));
-    year %= 100;
-    day += year + (year / 4);
-    day += MONTH_TO_WEEKDAY_TABLE[month]
-        - if is_leap_year(year) && month <= 1 {
-            1
-        } else {
-            0
-        };
-    (day % 7).try_into().expect("day is not valid usize")
-}
-
 fn main() {
     ctru::init();
 
@@ -81,30 +23,21 @@ fn main() {
             break;
         }
 
-        // Get the current time. ctru_sys bindings should be used rather than
+        // Technically, this actually just gets local time and assumes it's UTC,
-        // plain libc ones, for reasons I don't understand yet...
+        // since the 3DS doesn't seem to support timezones...
-        let unix_time: ctru_sys::time_t = unsafe { ctru_sys::time(std::ptr::null_mut()) };
+        let cur_time = time::OffsetDateTime::now_utc();
-        let time = unsafe { *ctru_sys::gmtime(&unix_time as *const _) };
 
-        let hours = time.tm_hour;
+        let hours = cur_time.hour();
-        let minutes = time.tm_min;
+        let minutes = cur_time.minute();
-        let seconds = time.tm_sec;
+        let seconds = cur_time.second();
-        let day = time.tm_mday;
-        let month = time.tm_mon;
-        let year = time.tm_year + 1900;
 
-        let month: usize = month.try_into().expect("month is not valid usize");
+        let weekday = cur_time.weekday().to_string();
+        let month = cur_time.month().to_string();
+        let day = cur_time.day();
+        let year = cur_time.year();
 
         println!("\x1b[1;1H{:0>2}:{:0>2}:{:0>2}", hours, minutes, seconds);
-        print!(
+        println!("{} {} {} {}", weekday, month, day, year);
-            "{} {} {} {}",
-            WEEKDAYS
-                .get(get_day_of_week(day, month, year))
-                .expect("invalid weekday"),
-            MONTHS[month],
-            day,
-            year
-        );
 
         // Flush and swap framebuffers
         gfx.flush_buffers();