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