add: Instant implementation

Author: Gavin-Niederman

library/std/src/sys/pal/vexos/mod.rs

@@ -20,7 +20,6 @@ pub mod stdio;
 pub mod thread;
 #[path = "../unsupported/thread_local_key.rs"]
 pub mod thread_local_key;
-#[path = "../unsupported/time.rs"]
 pub mod time;
 
 use crate::{arch::asm, ptr::{self, addr_of_mut}};

library/std/src/sys/pal/vexos/time.rs

@@ -0,0 +1,46 @@
+use crate::time::Duration;
+
+#[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Debug, Hash)]
+pub struct Instant(Duration);
+
+#[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Debug, Hash)]
+pub struct SystemTime(Duration);
+
+pub const UNIX_EPOCH: SystemTime = SystemTime(Duration::from_secs(0));
+
+impl Instant {
+    pub fn now() -> Instant {
+        let micros = unsafe { vex_sdk::vexSystemHighResTimeGet() };
+        Self(Duration::from_micros(micros))
+    }
+
+    pub fn checked_sub_instant(&self, other: &Instant) -> Option<Duration> {
+        self.0.checked_sub(other.0)
+    }
+
+    pub fn checked_add_duration(&self, other: &Duration) -> Option<Instant> {
+        Some(Instant(self.0.checked_add(*other)?))
+    }
+
+    pub fn checked_sub_duration(&self, other: &Duration) -> Option<Instant> {
+        Some(Instant(self.0.checked_sub(*other)?))
+    }
+}
+
+impl SystemTime {
+    pub fn now() -> SystemTime {
+        panic!("time not implemented on this platform")
+    }
+
+    pub fn sub_time(&self, other: &SystemTime) -> Result<Duration, Duration> {
+        self.0.checked_sub(other.0).ok_or_else(|| other.0 - self.0)
+    }
+
+    pub fn checked_add_duration(&self, other: &Duration) -> Option<SystemTime> {
+        Some(SystemTime(self.0.checked_add(*other)?))
+    }
+
+    pub fn checked_sub_duration(&self, other: &Duration) -> Option<SystemTime> {
+        Some(SystemTime(self.0.checked_sub(*other)?))
+    }
+}