meta: initial commit

src/one_to_many_with_data.rs

@@ -0,0 +1,71 @@
+use std::collections::{BTreeMap, BTreeSet};
+
+#[derive(Debug, Clone)]
+pub struct OneToManyUniqueBTreeMapWithData<Left, Right, RightData> {
+    left_to_rights: BTreeMap<Left, BTreeMap<Right, RightData>>,
+    right_to_left: BTreeMap<Right, Left>,
+}
+
+impl<Left, Right, RightData> Default for OneToManyUniqueBTreeMapWithData<Left, Right, RightData> {
+    fn default() -> Self {
+        Self {
+            left_to_rights: Default::default(),
+            right_to_left: Default::default(),
+        }
+    }
+}
+
+impl<Left, Right, RightData> OneToManyUniqueBTreeMapWithData<Left, Right, RightData>
+where
+    Left: Ord + Clone,
+    Right: Ord + Clone,
+{
+    /// Clones `left` and `right` so make sure it's cheap to do so
+    /// Returns whatever `Left` that `right` was already pointing to
+    pub fn insert(
+        &mut self,
+        left: Left,
+        right: Right,
+        right_data: RightData,
+    ) -> Option<(Left, Right, RightData)> {
+        let old = self.remove_right(&right);
+
+        self.left_to_rights
+            .entry(left.clone())
+            .or_default()
+            .insert(right.clone(), right_data);
+        self.right_to_left.insert(right, left);
+
+        old
+    }
+
+    pub fn get_rights_for(&self, left: &Left) -> Option<&BTreeMap<Right, RightData>> {
+        self.left_to_rights.get(left)
+    }
+
+    pub fn get_left_for(&self, right: &Right) -> Option<&Left> {
+        self.right_to_left.get(right)
+    }
+
+    pub fn remove_left(&mut self, left: &Left) -> Option<(Left, BTreeMap<Right, RightData>)> {
+        let (left, rights) = self.left_to_rights.remove_entry(left)?;
+
+        for (right, _right_data) in &rights {
+            self.right_to_left.remove(right);
+        }
+
+        Some((left, rights))
+    }
+
+    pub fn remove_right(&mut self, right: &Right) -> Option<(Left, Right, RightData)> {
+        let left = self.right_to_left.remove(right)?;
+        let rights = self.left_to_rights.get_mut(&left)?;
+        let (right, right_data) = rights.remove_entry(right)?;
+
+        if rights.is_empty() {
+            self.left_to_rights.remove(&left);
+        }
+
+        Some((left, right, right_data))
+    }
+}