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use crate::Vec;
use core::{borrow::Borrow, fmt, iter::FromIterator, mem, ops, slice};
/// A fixed capacity map / dictionary that performs lookups via linear search
///
/// Note that as this map doesn't use hashing so most operations are **O(N)** instead of O(1)
pub struct LinearMap<K, V, const N: usize> {
pub(crate) buffer: Vec<(K, V), N>,
}
impl<K, V, const N: usize> LinearMap<K, V, N> {
/// Creates an empty `LinearMap`
///
/// # Examples
///
/// ```
/// use heapless::LinearMap;
///
/// // allocate the map on the stack
/// let mut map: LinearMap<&str, isize, 8> = LinearMap::new();
///
/// // allocate the map in a static variable
/// static mut MAP: LinearMap<&str, isize, 8> = LinearMap::new();
/// ```
pub const fn new() -> Self {
Self { buffer: Vec::new() }
}
}
impl<K, V, const N: usize> LinearMap<K, V, N>
where
K: Eq,
{
/// Returns the number of elements that the map can hold
///
/// Computes in **O(1)** time
///
/// # Examples
///
/// ```
/// use heapless::LinearMap;
///
/// let map: LinearMap<&str, isize, 8> = LinearMap::new();
/// assert_eq!(map.capacity(), 8);
/// ```
pub fn capacity(&self) -> usize {
N
}
/// Clears the map, removing all key-value pairs
///
/// Computes in **O(1)** time
///
/// # Examples
///
/// ```
/// use heapless::LinearMap;
///
/// let mut map: LinearMap<_, _, 8> = LinearMap::new();
/// map.insert(1, "a").unwrap();
/// map.clear();
/// assert!(map.is_empty());
/// ```
pub fn clear(&mut self) {
self.buffer.clear()
}
/// Returns true if the map contains a value for the specified key.
///
/// Computes in **O(N)** time
///
/// # Examples
///
/// ```
/// use heapless::LinearMap;
///
/// let mut map: LinearMap<_, _, 8> = LinearMap::new();
/// map.insert(1, "a").unwrap();
/// assert_eq!(map.contains_key(&1), true);
/// assert_eq!(map.contains_key(&2), false);
/// ```
pub fn contains_key(&self, key: &K) -> bool {
self.get(key).is_some()
}
/// Returns a reference to the value corresponding to the key
///
/// Computes in **O(N)** time
///
/// # Examples
///
/// ```
/// use heapless::LinearMap;
///
/// let mut map: LinearMap<_, _, 8> = LinearMap::new();
/// map.insert(1, "a").unwrap();
/// assert_eq!(map.get(&1), Some(&"a"));
/// assert_eq!(map.get(&2), None);
/// ```
pub fn get<Q>(&self, key: &Q) -> Option<&V>
where
K: Borrow<Q>,
Q: Eq + ?Sized,
{
self.iter()
.find(|&(k, _)| k.borrow() == key)
.map(|(_, v)| v)
}
/// Returns a mutable reference to the value corresponding to the key
///
/// Computes in **O(N)** time
///
/// # Examples
///
/// ```
/// use heapless::LinearMap;
///
/// let mut map: LinearMap<_, _, 8> = LinearMap::new();
/// map.insert(1, "a").unwrap();
/// if let Some(x) = map.get_mut(&1) {
/// *x = "b";
/// }
/// assert_eq!(map[&1], "b");
/// ```
pub fn get_mut<Q>(&mut self, key: &Q) -> Option<&mut V>
where
K: Borrow<Q>,
Q: Eq + ?Sized,
{
self.iter_mut()
.find(|&(k, _)| k.borrow() == key)
.map(|(_, v)| v)
}
/// Returns the number of elements in this map
///
/// Computes in **O(1)** time
///
/// # Examples
///
/// ```
/// use heapless::LinearMap;
///
/// let mut a: LinearMap<_, _, 8> = LinearMap::new();
/// assert_eq!(a.len(), 0);
/// a.insert(1, "a").unwrap();
/// assert_eq!(a.len(), 1);
/// ```
pub fn len(&self) -> usize {
self.buffer.len()
}
/// Inserts a key-value pair into the map.
///
/// If the map did not have this key present, `None` is returned.
///
/// If the map did have this key present, the value is updated, and the old value is returned.
///
/// Computes in **O(N)** time
///
/// # Examples
///
/// ```
/// use heapless::LinearMap;
///
/// let mut map: LinearMap<_, _, 8> = LinearMap::new();
/// assert_eq!(map.insert(37, "a").unwrap(), None);
/// assert_eq!(map.is_empty(), false);
///
/// map.insert(37, "b").unwrap();
/// assert_eq!(map.insert(37, "c").unwrap(), Some("b"));
/// assert_eq!(map[&37], "c");
/// ```
pub fn insert(&mut self, key: K, mut value: V) -> Result<Option<V>, (K, V)> {
if let Some((_, v)) = self.iter_mut().find(|&(k, _)| *k == key) {
mem::swap(v, &mut value);
return Ok(Some(value));
}
self.buffer.push((key, value))?;
Ok(None)
}
/// Returns true if the map contains no elements
///
/// Computes in **O(1)** time
///
/// # Examples
///
/// ```
/// use heapless::LinearMap;
///
/// let mut a: LinearMap<_, _, 8> = LinearMap::new();
/// assert!(a.is_empty());
/// a.insert(1, "a").unwrap();
/// assert!(!a.is_empty());
/// ```
pub fn is_empty(&self) -> bool {
self.len() == 0
}
/// An iterator visiting all key-value pairs in arbitrary order.
///
/// # Examples
///
/// ```
/// use heapless::LinearMap;
///
/// let mut map: LinearMap<_, _, 8> = LinearMap::new();
/// map.insert("a", 1).unwrap();
/// map.insert("b", 2).unwrap();
/// map.insert("c", 3).unwrap();
///
/// for (key, val) in map.iter() {
/// println!("key: {} val: {}", key, val);
/// }
/// ```
pub fn iter(&self) -> Iter<'_, K, V> {
Iter {
iter: self.buffer.as_slice().iter(),
}
}
/// An iterator visiting all key-value pairs in arbitrary order, with mutable references to the
/// values
///
/// # Examples
///
/// ```
/// use heapless::LinearMap;
///
/// let mut map: LinearMap<_, _, 8> = LinearMap::new();
/// map.insert("a", 1).unwrap();
/// map.insert("b", 2).unwrap();
/// map.insert("c", 3).unwrap();
///
/// // Update all values
/// for (_, val) in map.iter_mut() {
/// *val = 2;
/// }
///
/// for (key, val) in &map {
/// println!("key: {} val: {}", key, val);
/// }
/// ```
pub fn iter_mut(&mut self) -> IterMut<'_, K, V> {
IterMut {
iter: self.buffer.as_mut_slice().iter_mut(),
}
}
/// An iterator visiting all keys in arbitrary order
///
/// # Examples
///
/// ```
/// use heapless::LinearMap;
///
/// let mut map: LinearMap<_, _, 8> = LinearMap::new();
/// map.insert("a", 1).unwrap();
/// map.insert("b", 2).unwrap();
/// map.insert("c", 3).unwrap();
///
/// for key in map.keys() {
/// println!("{}", key);
/// }
/// ```
pub fn keys(&self) -> impl Iterator<Item = &K> {
self.iter().map(|(k, _)| k)
}
/// Removes a key from the map, returning the value at the key if the key was previously in the
/// map
///
/// Computes in **O(N)** time
///
/// # Examples
///
/// ```
/// use heapless::LinearMap;
///
/// let mut map: LinearMap<_, _, 8> = LinearMap::new();
/// map.insert(1, "a").unwrap();
/// assert_eq!(map.remove(&1), Some("a"));
/// assert_eq!(map.remove(&1), None);
/// ```
pub fn remove<Q>(&mut self, key: &Q) -> Option<V>
where
K: Borrow<Q>,
Q: Eq + ?Sized,
{
let idx = self
.keys()
.enumerate()
.find(|&(_, k)| k.borrow() == key)
.map(|(idx, _)| idx);
idx.map(|idx| self.buffer.swap_remove(idx).1)
}
/// An iterator visiting all values in arbitrary order
///
/// # Examples
///
/// ```
/// use heapless::LinearMap;
///
/// let mut map: LinearMap<_, _, 8> = LinearMap::new();
/// map.insert("a", 1).unwrap();
/// map.insert("b", 2).unwrap();
/// map.insert("c", 3).unwrap();
///
/// for val in map.values() {
/// println!("{}", val);
/// }
/// ```
pub fn values(&self) -> impl Iterator<Item = &V> {
self.iter().map(|(_, v)| v)
}
/// An iterator visiting all values mutably in arbitrary order
///
/// # Examples
///
/// ```
/// use heapless::LinearMap;
///
/// let mut map: LinearMap<_, _, 8> = LinearMap::new();
/// map.insert("a", 1).unwrap();
/// map.insert("b", 2).unwrap();
/// map.insert("c", 3).unwrap();
///
/// for val in map.values_mut() {
/// *val += 10;
/// }
///
/// for val in map.values() {
/// println!("{}", val);
/// }
/// ```
pub fn values_mut(&mut self) -> impl Iterator<Item = &mut V> {
self.iter_mut().map(|(_, v)| v)
}
}
impl<'a, K, V, Q, const N: usize> ops::Index<&'a Q> for LinearMap<K, V, N>
where
K: Borrow<Q> + Eq,
Q: Eq + ?Sized,
{
type Output = V;
fn index(&self, key: &Q) -> &V {
self.get(key).expect("no entry found for key")
}
}
impl<'a, K, V, Q, const N: usize> ops::IndexMut<&'a Q> for LinearMap<K, V, N>
where
K: Borrow<Q> + Eq,
Q: Eq + ?Sized,
{
fn index_mut(&mut self, key: &Q) -> &mut V {
self.get_mut(key).expect("no entry found for key")
}
}
impl<K, V, const N: usize> Default for LinearMap<K, V, N>
where
K: Eq,
{
fn default() -> Self {
Self::new()
}
}
impl<K, V, const N: usize> Clone for LinearMap<K, V, N>
where
K: Eq + Clone,
V: Clone,
{
fn clone(&self) -> Self {
Self {
buffer: self.buffer.clone(),
}
}
}
impl<K, V, const N: usize> fmt::Debug for LinearMap<K, V, N>
where
K: Eq + fmt::Debug,
V: fmt::Debug,
{
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
f.debug_map().entries(self.iter()).finish()
}
}
impl<K, V, const N: usize> FromIterator<(K, V)> for LinearMap<K, V, N>
where
K: Eq,
{
fn from_iter<I>(iter: I) -> Self
where
I: IntoIterator<Item = (K, V)>,
{
let mut out = Self::new();
out.buffer.extend(iter);
out
}
}
pub struct IntoIter<K, V, const N: usize>
where
K: Eq,
{
inner: <Vec<(K, V), N> as IntoIterator>::IntoIter,
}
impl<K, V, const N: usize> Iterator for IntoIter<K, V, N>
where
K: Eq,
{
type Item = (K, V);
fn next(&mut self) -> Option<Self::Item> {
self.inner.next()
}
}
impl<'a, K, V, const N: usize> IntoIterator for &'a LinearMap<K, V, N>
where
K: Eq,
{
type Item = (&'a K, &'a V);
type IntoIter = Iter<'a, K, V>;
fn into_iter(self) -> Self::IntoIter {
self.iter()
}
}
pub struct Iter<'a, K, V> {
iter: slice::Iter<'a, (K, V)>,
}
impl<'a, K, V> Iterator for Iter<'a, K, V> {
type Item = (&'a K, &'a V);
fn next(&mut self) -> Option<Self::Item> {
self.iter.next().map(|&(ref k, ref v)| (k, v))
}
}
impl<'a, K, V> Clone for Iter<'a, K, V> {
fn clone(&self) -> Self {
Self {
iter: self.iter.clone(),
}
}
}
pub struct IterMut<'a, K, V> {
iter: slice::IterMut<'a, (K, V)>,
}
impl<'a, K, V> Iterator for IterMut<'a, K, V> {
type Item = (&'a K, &'a mut V);
fn next(&mut self) -> Option<Self::Item> {
self.iter.next().map(|&mut (ref k, ref mut v)| (k, v))
}
}
impl<K, V, const N: usize, const N2: usize> PartialEq<LinearMap<K, V, N2>> for LinearMap<K, V, N>
where
K: Eq,
V: PartialEq,
{
fn eq(&self, other: &LinearMap<K, V, N2>) -> bool {
self.len() == other.len()
&& self
.iter()
.all(|(key, value)| other.get(key).map_or(false, |v| *value == *v))
}
}
impl<K, V, const N: usize> Eq for LinearMap<K, V, N>
where
K: Eq,
V: PartialEq,
{
}
#[cfg(test)]
mod test {
use crate::LinearMap;
#[test]
fn static_new() {
static mut _L: LinearMap<i32, i32, 8> = LinearMap::new();
}
#[test]
fn partial_eq() {
{
let mut a = LinearMap::<_, _, 1>::new();
a.insert("k1", "v1").unwrap();
let mut b = LinearMap::<_, _, 2>::new();
b.insert("k1", "v1").unwrap();
assert!(a == b);
b.insert("k2", "v2").unwrap();
assert!(a != b);
}
{
let mut a = LinearMap::<_, _, 2>::new();
a.insert("k1", "v1").unwrap();
a.insert("k2", "v2").unwrap();
let mut b = LinearMap::<_, _, 2>::new();
b.insert("k2", "v2").unwrap();
b.insert("k1", "v1").unwrap();
assert!(a == b);
}
}
#[test]
fn drop() {
droppable!();
{
let mut v: LinearMap<i32, Droppable, 2> = LinearMap::new();
v.insert(0, Droppable::new()).ok().unwrap();
v.insert(1, Droppable::new()).ok().unwrap();
v.remove(&1).unwrap();
}
assert_eq!(Droppable::count(), 0);
{
let mut v: LinearMap<i32, Droppable, 2> = LinearMap::new();
v.insert(0, Droppable::new()).ok().unwrap();
v.insert(1, Droppable::new()).ok().unwrap();
}
assert_eq!(Droppable::count(), 0);
}
}