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// Copyright 2019 Eric Izoita (nytopop) // // Permission is hereby granted, free of charge, to any person obtaining a copy // of this software and associated documentation files (the "Software"), to deal // in the Software without restriction, including without limitation the rights // to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies // of the Software, and to permit persons to whom the Software is furnished to // do so, subject to the following conditions: // // The above copyright notice and this permission notice shall be included in // all copies or substantial portions of the Software. // // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING // FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS // IN THE SOFTWARE. use std::mem; pub trait Set<T> { /// Add val to the set. /// /// If the set did not have this value present, `true` is returned. /// /// If the set did have this value present, `false` is returned. fn set_insert(&mut self, t: T) -> bool; } impl<T: Ord> Set<T> for Vec<T> { /// O(n + log n) /// /// ``` /// use consistent_hash_ring::collections::Set; /// /// let mut set = Vec::new(); /// /// assert!(set.set_insert(0)); /// assert!(!set.set_insert(0)); /// assert!(set.set_insert(5)); /// assert!(!set.set_insert(5)); /// assert!(set.set_insert(3)); /// assert!(!set.set_insert(3)); /// assert_eq!(vec![0, 3, 5], set); /// ``` fn set_insert(&mut self, val: T) -> bool { self.binary_search(&val) .map_err(|i| self.insert(i, val)) .is_err() } } pub trait Map<K, V> { /// Insert a value at key. /// /// Returns `None` if the key doesn't exist, and `Some(old_value)` when /// it does. fn map_insert(&mut self, key: K, val: V) -> Option<V>; /// Remove the value at key. /// /// Returns `None` if the key doesn't exist. fn map_remove(&mut self, key: &K) -> Option<(K, V)>; /// Lookup the value at key. /// /// Returns `None` if the key doesn't exist. fn map_lookup(&self, key: &K) -> Option<&V>; /// Find the smallest key that is greater than or equal to key, wrapping /// to zero if there isn't one. /// /// Returns `None` if the map is empty. fn find_gte(&self, key: &K) -> Option<&V>; } #[inline] pub(crate) fn first<L, R>(tup: &(L, R)) -> &L { &tup.0 } #[inline] pub(crate) fn second<L, R>(tup: &(L, R)) -> &R { &tup.1 } impl<K: Ord, V> Map<K, V> for Vec<(K, V)> { /// O(n + log n) /// /// ``` /// use consistent_hash_ring::collections::Map; /// /// let mut map = (0..2).map(|x|(x,x)).collect::<Vec<_>>(); /// /// assert_eq!(None, map.map_insert(2, 42)); /// assert_eq!(vec![(0, 0), (1, 1), (2, 42)], map); /// assert_eq!(Some(42), map.map_insert(2, 24)); /// assert_eq!(vec![(0, 0), (1, 1), (2, 24)], map); /// ``` fn map_insert(&mut self, key: K, val: V) -> Option<V> { match self.binary_search_by_key(&&key, first) { Err(i) => { self.insert(i, (key, val)); Err(()) } Ok(i) => Ok(mem::replace( &mut unsafe { self.get_unchecked_mut(i) }.1, val, )), } .ok() } /// O(n + log n) /// /// ``` /// use consistent_hash_ring::collections::Map; /// /// let mut map = (0..2).map(|x|(x,x)).collect::<Vec<_>>(); /// /// assert_eq!(None, map.map_remove(&4)); /// assert_eq!(Some((1, 1)), map.map_remove(&1)); /// assert_eq!(vec![(0, 0)], map); /// ``` fn map_remove(&mut self, key: &K) -> Option<(K, V)> { self.binary_search_by_key(&key, first) .map(|i| self.remove(i)) .ok() } /// O(log n) /// /// ``` /// use consistent_hash_ring::collections::Map; /// /// let mut map = (0..2).map(|x|(x,x)).collect::<Vec<_>>(); /// /// assert_eq!(Some(&1), map.map_lookup(&1)); /// assert_eq!(None, map.map_lookup(&3)); /// ``` fn map_lookup(&self, key: &K) -> Option<&V> { self.binary_search_by_key(&key, first) .map(|i| unsafe { self.get_unchecked(i) }) .map(second) .ok() } /// O(log n) /// /// ``` /// use consistent_hash_ring::collections::Map; /// /// let mut map = Vec::default(); /// /// assert_eq!(None, map.find_gte(&0)); /// assert_eq!(None, map.map_insert(1, 2)); /// assert_eq!(None, map.map_insert(2, 3)); /// assert_eq!(None, map.map_insert(3, 4)); /// assert_eq!(vec![(1, 2), (2, 3), (3, 4)], map); /// assert_eq!(Some(&2), map.find_gte(&0)); /// assert_eq!(Some(&2), map.find_gte(&1)); /// assert_eq!(Some(&3), map.find_gte(&2)); /// assert_eq!(Some(&4), map.find_gte(&3)); /// assert_eq!(Some(&2), map.find_gte(&4)); /// ``` fn find_gte(&self, key: &K) -> Option<&V> { let checked = |i| match self.len() { n if n == 0 => None, n if n == i => Some(0), _ => Some(i), }; self.binary_search_by_key(&key, first) .map_or_else(checked, Some) .map(|i| unsafe { self.get_unchecked(i) }) .map(second) } }