timer revelations

src/timer.rs

@@ -1,18 +1,26 @@
 use crate::integer::{Time,Ratio64};
 
-//this could be about half as long if I only had
-//scaled timers and just used a scale of 1
-//but I thought the concept of a timer that could
-//only be paused and not scaled was cool
+pub struct Paused{}
+pub struct Unpaused{}
 
-trait TimerState:Copy{
-	fn get_time(&self,time:Time)->Time;
-	fn set_time(&mut self,time:Time,new_time:Time);
-	fn get_offset(&self)->Time;
-	fn set_offset(&mut self,offset:Time);
+pub trait PauseState{
+	const IS_PAUSED:bool;
+}
+impl PauseState for Paused{
+	const IS_PAUSED:bool=true;
+}
+impl PauseState for Unpaused{
+	const IS_PAUSED:bool=false;
 }
 
-#[derive(Clone,Copy,Debug)]
+pub struct Realtime{
+	offset:Time,
+}
+impl Realtime{
+	const fn identity()->Self{
+		Self{offset:Time::ZERO}
+	}
+}
 pub struct Scaled{
 	scale:Ratio64,
 	offset:Time,
@@ -36,29 +44,12 @@ impl Scaled{
 		self.set_time(time,new_time);
 	}
 }
-impl TimerState for Scaled{
-	fn get_time(&self,time:Time)->Time{
-		self.scale(time)+self.offset
-	}
-	fn set_time(&mut self,time:Time,new_time:Time){
-		self.offset=new_time-self.scale(time);
-	}
-	fn get_offset(&self)->Time{
-		self.offset
-	}
-	fn set_offset(&mut self,offset:Time){
-		self.offset=offset;
-	}
-}
 
-#[derive(Clone,Copy,Debug)]
-pub struct Realtime{
-	offset:Time,
-}
-impl Realtime{
-	const fn identity()->Self{
-		Self{offset:Time::ZERO}
-	}
+pub trait TimerState{
+	fn get_time(&self,time:Time)->Time;
+	fn set_time(&mut self,time:Time,new_time:Time);
+	fn get_offset(&self)->Time;
+	fn set_offset(&mut self,offset:Time);
 }
 impl TimerState for Realtime{
 	fn get_time(&self,time:Time)->Time{
@@ -74,28 +65,33 @@ impl TimerState for Realtime{
 		self.offset=offset;
 	}
 }
-
-#[derive(Clone,Debug)]
-pub struct Timer<T>{
-	state:T,
-	paused:bool,
+impl TimerState for Scaled{
+	fn get_time(&self,time:Time)->Time{
+		self.scale(time)+self.offset
+	}
+	fn set_time(&mut self,time:Time,new_time:Time){
+		self.offset=new_time-self.scale(time);
+	}
+	fn get_offset(&self)->Time{
+		self.offset
+	}
+	fn set_offset(&mut self,offset:Time){
+		self.offset=offset;
+	}
 }
 
-impl Timer<Realtime>{
-	pub fn realtime(time:Time,new_time:Time)->Self{
-		let mut timer=Self{
-			state:Realtime::identity(),
-			paused:false,
-		};
-		timer.set_time(time,new_time);
-		timer
-	}
-	pub fn realtime_paused(offset:Time)->Self{
-		Self{
-			state:Realtime{offset},
-			paused:true,
-		}
-	}
+pub struct TimerFixed<T:TimerState,P:PauseState>{
+	state:T,
+	paused:P,
+}
+
+pub enum Timer{
+	Paused(TimerFixed<Realtime,Paused>),
+	Unpaused(TimerFixed<Realtime,Unpaused>),
+}
+pub enum TimerScaled{
+	Paused(TimerFixed<Scaled,Paused>),
+	Unpaused(TimerFixed<Scaled,Unpaused>),
 }
 
 #[derive(Debug)]
@@ -110,100 +106,45 @@ impl std::fmt::Display for Error{
 }
 impl std::error::Error for Error{}
 
-impl Timer<Scaled>{
-	pub fn new(time:Time,new_time:Time,scale:Ratio64,paused:bool)->Self{
-		let mut timer=Self{
-			state:Scaled::with_scale(scale),
-			paused,
-		};
-		timer.set_time(time,new_time);
-		timer
-	}
-	pub fn scaled(time:Time,new_time:Time,scale:Ratio64)->Self{
-		let mut timer=Self{
-			state:Scaled::with_scale(scale),
-			paused:false,
-		};
-		timer.set_time(time,new_time);
-		timer
-	}
-	pub fn scaled_paused(time:Time,new_time:Time,scale:Ratio64)->Self{
-		let mut timer=Self{
-			state:Scaled::with_scale(scale),
-			paused:true,
-		};
-		timer.set_time(time,new_time);
-		timer
-	}
-	pub const fn get_scale(&self)->Ratio64{
-		self.state.get_scale()
-	}
-	pub fn set_scale(&mut self,time:Time,new_scale:Ratio64){
-		self.state.set_scale(time,new_scale)
-	}
-}
-
-impl<T:TimerState> Timer<T>{
+impl<T:TimerState,P:PauseState> TimerFixed<T,P>{
 	pub fn time(&self,time:Time)->Time{
-		match self.paused{
+		match P::IS_PAUSED{
 			true=>self.state.get_offset(),
 			false=>self.state.get_time(time),
 		}
 	}
 	pub fn set_time(&mut self,time:Time,new_time:Time){
-		match self.paused{
+		match P::IS_PAUSED{
 			true=>self.state.set_offset(new_time),
 			false=>self.state.set_time(time,new_time),
 		}
 	}
-	pub fn pause(&mut self,time:Time)->Result<(),Error>{
-		match self.paused{
+	pub fn pause(self,time:Time)->Result<TimerFixed<T,Paused>,Error>{
+		match P::IS_PAUSED{
 			true=>Err(Error::AlreadyPaused),
 			false=>{
 				let new_time=self.time(time);
-				self.state.set_offset(new_time);
-				self.paused=true;
-				Ok(())
+				let mut timer=TimerFixed{
+					state:self.state,
+					paused:Paused{},
+				};
+				timer.set_time(time,new_time);
+				Ok(timer)
 			},
 		}
 	}
-	pub fn unpause(&mut self,time:Time)->Result<(),Error>{
-		match self.paused{
+	pub fn unpause(self,time:Time)->Result<TimerFixed<T,Unpaused>,Error>{
+		match P::IS_PAUSED{
 			true=>{
 				let new_time=self.time(time);
-				self.state.set_time(time,new_time);
-				self.paused=false;
-				Ok(())
+				let mut timer=TimerFixed{
+					state:self.state,
+					paused:Unpaused{},
+				};
+				timer.set_time(time,new_time);
+				Ok(timer)
 			},
 			false=>Err(Error::AlreadyUnpaused),
 		}
 	}
 }
-#[cfg(test)]
-mod test{
-	use super::{Time,Timer,Error};
-	macro_rules! sec {
-		($s: expr) => {
-			Time::from_secs($s)
-		};
-	}
-	#[test]
-	fn test_timer()->Result<(),Error>{
-		//create a paused timer that reads 0s
-		let mut timer=Timer::realtime_paused(sec!(0));
-		//the paused timer at 1 second should read 0s
-		assert_eq!(timer.time(sec!(1)),sec!(0));
-
-		//unpause it after one second
-		timer.unpause(sec!(1))?;
-		//the timer at 6 seconds should read 5s
-		assert_eq!(timer.time(sec!(6)),sec!(5));
-
-		//pause the timer after 11 seconds
-		timer.pause(sec!(11))?;
-		//the paused timer at 20 seconds should read 10s
-		assert_eq!(timer.time(sec!(20)),sec!(10));
-
-		Ok(())
-	}
-}