different parser for ticks from filenames

sim/Cargo.toml

@@ -19,6 +19,7 @@ ordered-float = "0.5.0"
 pretty_assertions = "0.5.1"
 rand = { version = "0.5.1", features = ["serde1"] }
 rayon = "1.0"
+regex = "1.0.6"
 serde = "1.0"
 serde_derive = "1.0"
 structopt = "0.2"

sim/src/lib.rs

@@ -21,6 +21,7 @@ extern crate ordered_float;
 extern crate pretty_assertions;
 extern crate rand;
 extern crate rayon;
+extern crate regex;
 extern crate serde;
 #[macro_use]
 extern crate serde_derive;

sim/src/physics.rs

@@ -1,5 +1,6 @@
 use dimensioned::si;
 use rand::{Rng, XorShiftRng};
+use regex::Regex;
 
 pub const TIMESTEP: Time = si::Second {
     value_unsafe: 0.1,
@@ -29,6 +30,7 @@ impl Tick {
         Tick(10 * secs)
     }
 
+    // TODO Why have these two forms? Consolidate
     pub fn parse(string: &str) -> Option<Tick> {
         let parts: Vec<&str> = string.split(":").collect();
         if parts.is_empty() {
@@ -62,6 +64,19 @@ impl Tick {
         }
     }
 
+    pub fn parse_filename(string: &str) -> Option<Tick> {
+        lazy_static! {
+            static ref RE: Regex = Regex::new(r"(\d+)h(\d+)m(\d+)\.(\d+)s").unwrap();
+        }
+        let caps = RE.captures(string)?;
+        let hours = 60 * 60 * 10 * u32::from_str_radix(&caps[1], 10).ok()?;
+        let minutes = 60 * 10 * u32::from_str_radix(&caps[2], 10).ok()?;
+        let seconds = 10 * u32::from_str_radix(&caps[3], 10).ok()?;
+        let ms = u32::from_str_radix(&caps[4], 10).ok()?;
+
+        Some(Tick(hours + minutes + seconds + ms))
+    }
+
     pub fn as_time(&self) -> Time {
         (self.0 as f64) * TIMESTEP
     }

sim/src/sim.rs

@@ -313,9 +313,9 @@ impl Sim {
 
     // TODO Return a descriptive error again
     pub fn load_most_recent(&self) -> Result<Sim, std::io::Error> {
-        let (_, load) = self.find_all_savestates().and_then(|mut list| {
-            list.pop().ok_or(io_error("empty directory"))
-        })?;
+        let (_, load) = self
+            .find_all_savestates()
+            .and_then(|mut list| list.pop().ok_or(io_error("empty directory")))?;
         info!("Loading {}", load);
         abstutil::read_json(&load)
     }
@@ -334,7 +334,8 @@ impl Sim {
                 .to_os_string()
                 .into_string()
                 .expect("can't convert path to string");
-            let tick = Tick::parse(&filename).expect(&format!("invalid Tick: {}", filename));
+            let tick =
+                Tick::parse_filename(&filename).expect(&format!("invalid Tick: {}", filename));
             results.push((
                 tick,
                 path.as_path()