base-station: Implement storing/retrieving the most recent set of values.

base-station/software/src/current.rs

+use std::collections::HashMap;
+
+use log::error;
+
 use protocol::{Location, Value, ValueType};
 
 pub struct CurrentValues {
-    // TODO
+    map: HashMap<Key, i64>,
 }
 
 impl CurrentValues {
     pub fn new() -> CurrentValues {
-        CurrentValues {}
+        CurrentValues {
+            map: HashMap::new(),
+        }
     }
 
-    pub fn set(&mut self, location: Location, _value: Value) {
-        // TODO
+    pub fn set(&mut self, location: Location, value: Value) {
+        let (type_, value) = match value.split() {
+            Some(x) => x,
+            None => {
+                error!("Invalid value passed to CurrentValues::set().");
+                return;
+            }
+        };
+        self.map.insert(Key { location, type_ }, value);
     }
 
-    pub fn get(&self, location: Location, _value: ValueType) -> Option<Value> {
-        // TODO
-        None
+    pub fn get(&self, location: Location, type_: ValueType) -> Option<Value> {
+        let entry = self.map.get(&Key { location, type_ })?.clone();
+        Some(Value::combine(type_, entry))
     }
 }
+
+#[derive(Copy, Clone, PartialEq, Eq, Hash)]
+struct Key {
+    location: Location,
+    type_: ValueType,
+}