added comments to container_type

This commit is contained in:
Sven Vogel 2023-05-26 09:02:36 +02:00
parent 51e769be91
commit ce79d8e644
2 changed files with 29 additions and 2 deletions

View File

@ -6,9 +6,11 @@
<sourceFolder url="file://$MODULE_DIR$/duplicates/src" isTestSource="false" />
<sourceFolder url="file://$MODULE_DIR$/str_sort/src" isTestSource="false" />
<sourceFolder url="file://$MODULE_DIR$/sparse_vector/src" isTestSource="false" />
<sourceFolder url="file://$MODULE_DIR$/container_type/src" isTestSource="false" />
<excludeFolder url="file://$MODULE_DIR$/duplicates/target" />
<excludeFolder url="file://$MODULE_DIR$/str_sort/target" />
<excludeFolder url="file://$MODULE_DIR$/sparse_vector/target" />
<excludeFolder url="file://$MODULE_DIR$/container_type/target" />
</content>
<orderEntry type="inheritedJdk" />
<orderEntry type="sourceFolder" forTests="false" />

View File

@ -17,15 +17,35 @@ use std::{vec::{IntoIter}, ops::Index, ops::IndexMut, println};
* Copyright (c) Sven Vogel
*/
/// A vector based implementation of an associative map.
/// This strucutre maps a given key to a single value.
/// The type achives this by storing every pair of key/value pairs
/// in a single vector.
/// Thus for looking up a value takes a linear amount of time: O(n) in the worst case.
/// Adding a new value is a constant time operation since the map is not sorted in any
/// particular way.
/// Note that it is not possible to insert a new value with the same key. Instead the old value
/// associated with the already existing key will be replaced with the new value.
/// # Example
/// ```rust ignore
/// let mut map = HashishMap::new();
///
/// map.insert("abc", 99);
///
/// map[&"abc"] += 1;
/// ```
pub struct HashishMap<K, V> where K: Eq {
vec: Vec<(K, V)>
}
impl<K, V> HashishMap<K, V> where K: Eq {
/// Create a new empty instance
pub fn new() -> Self {
Self { vec: vec![] }
}
/// retrieve a reference to value associated with the specified key
/// if no such key exists in the map [`Option::None`] is returned
pub fn get(&self, key: &K) -> Option<&V> {
return match self.vec.iter().find(|(k, _)| *k == *key) {
Some((_, v)) => Some(v),
@ -33,6 +53,8 @@ impl<K, V> HashishMap<K, V> where K: Eq {
}
}
/// retrieve a mutable reference to value associated with the specified key
/// if no such key exists in the map [`Option::None`] is returned
pub fn get_mut(&mut self, key: &K) -> Option<&mut V> {
return match self.vec.iter_mut().find(|(k, _)| *k == *key) {
Some((_, v)) => Some(v),
@ -40,6 +62,9 @@ impl<K, V> HashishMap<K, V> where K: Eq {
}
}
/// insert a new value at the specified key.
/// Overrides the existing value if the key already exists.
/// The overriden value is discarded.
pub fn insert(&mut self, key: K, value: V) {
if let Some(val) = self.get_mut(&key) {
*val = value;
@ -48,6 +73,8 @@ impl<K, V> HashishMap<K, V> where K: Eq {
}
}
/// Removes the key/value pair with the specified key from the map and return the value of the pair.
/// If no such pair can be found, [`Option::None`] is retuned
pub fn remove(&mut self, key: &K) -> Option<V> {
// find a key matching the parameter and its according index.
// remove the item at the found index from the vector and return its value
@ -68,7 +95,6 @@ impl<K,V> Index<K> for HashishMap<K, V> where K: Eq {
}
}
impl<K,V> IndexMut<K> for HashishMap<K, V> where K: Eq {
fn index_mut(&mut self, index: K) -> &mut Self::Output {
@ -101,5 +127,4 @@ fn main() {
for (k, v) in guter_stoff {
println!("({k}, {:x})", v);
}
}