HashMap and HashSet

Cargo.toml

@@ -15,6 +15,20 @@ rust-version = "nightly"
 [package.metadata.docs.rs]
 rustdoc-args = ["--cfg", "nightly"]
 
+[dependencies.hashbrown]
+version = "0.15.1"
+optional = true
+default-features = false
+features = [
+    "nightly",
+    "default-hasher",
+    "inline-more",
+    "allocator-api2",
+    "equivalent",
+    "raw-entry"
+]
+
 [features]
-default = []
+default = ["hash_collections"]
+hash_collections = ["hashbrown"]
 no_std = []

README.md

@@ -7,6 +7,8 @@ The wrapper collection types provide two main benefits:
 * They can't be used incorrectly by virtue of lacking APIs which panic.
 * Provide additional convenience methods for working with the collection in a checked manner.
 
+*N.B.:* You might find the [`heapless`](https://docs.rs/heapless/latest/heapless/) crate useful too!
+
 ## Restrictions
 
 The crate requires a recent build of the Rust "nightly" compiler, as it uses the

src/claim.rs

@@ -1,3 +1,4 @@
+use alloc::alloc::Global;
 use alloc::rc::Rc;
 use alloc::sync::Arc;
 use core::convert::Infallible;
@@ -26,7 +27,7 @@ macro_rules! impl_claim_for {
 impl_claim_for! {
     (), u8, u16, u32, u64, u128, usize,
     i8, i16, i32, i64, i128, isize,
-    f32, f64, bool, char
+    f32, f64, bool, char, Global
 }
 
 impl<T: ?Sized> Claim for *const T {}

src/hash/map.rs

@@ -0,0 +1,106 @@
+use crate::claim::Claim;
+use core::alloc::Allocator;
+use core::hash::{BuildHasher, Hash};
+pub use hashbrown::hash_map::{Iter, IterMut, Keys, Values, ValuesMut};
+pub use hashbrown::DefaultHashBuilder;
+use hashbrown::{HashMap as InnerHashMap, TryReserveError};
+
+pub struct HashMap<K, V, A: Allocator, S = DefaultHashBuilder> {
+    inner: InnerHashMap<K, V, S, A>,
+}
+
+impl<K, V, A: Allocator + Claim> HashMap<K, V, A, DefaultHashBuilder> {
+    #[inline]
+    pub fn new_in(alloc: A) -> Self {
+        Self::with_hasher_in(DefaultHashBuilder::default(), alloc)
+    }
+
+    #[inline]
+    pub fn with_capacity_in(capacity: usize, alloc: A) -> Self {
+        Self::with_capacity_and_hasher_in(capacity, DefaultHashBuilder::default(), alloc)
+    }
+}
+
+impl<K, V, A: Allocator + Claim, S> HashMap<K, V, A, S> {
+    #[inline]
+    pub fn allocator(&self) -> &A {
+        self.inner.allocator()
+    }
+
+    #[inline]
+    pub fn with_hasher_in(hash_builder: S, alloc: A) -> Self {
+        Self {
+            inner: InnerHashMap::with_hasher_in(hash_builder, alloc),
+        }
+    }
+
+    #[inline]
+    pub fn with_capacity_and_hasher_in(capacity: usize, hash_builder: S, alloc: A) -> Self {
+        Self {
+            inner: InnerHashMap::with_capacity_and_hasher_in(capacity, hash_builder, alloc),
+        }
+    }
+
+    #[inline]
+    pub fn hasher(&self) -> &S {
+        self.inner.hasher()
+    }
+
+    #[inline]
+    pub fn capacity(&self) -> usize {
+        self.inner.capacity()
+    }
+
+    #[inline]
+    pub fn clear(&mut self) {
+        // TODO(amunra): May this reallocate memory?
+    }
+
+    #[inline]
+    pub fn is_empty(&self) -> bool {
+        self.inner.is_empty()
+    }
+
+    #[inline]
+    pub fn keys(&self) -> Keys<'_, K, V> {
+        self.inner.keys()
+    }
+
+    #[inline]
+    pub fn values(&self) -> Values<'_, K, V> {
+        self.inner.values()
+    }
+
+    #[inline]
+    pub fn values_mut(&mut self) -> ValuesMut<'_, K, V> {
+        self.inner.values_mut()
+    }
+
+    #[inline]
+    pub fn iter(&self) -> Iter<'_, K, V> {
+        self.inner.iter()
+    }
+
+    #[inline]
+    pub fn iter_mut(&mut self) -> IterMut<'_, K, V> {
+        self.inner.iter_mut()
+    }
+}
+
+impl<K, V, A, S> HashMap<K, V, A, S>
+where
+    K: Eq + Hash,
+    A: Allocator + Claim,
+    S: BuildHasher,
+{
+    #[inline]
+    pub fn reserve(&mut self, additional: usize) -> Result<(), TryReserveError> {
+        self.inner.try_reserve(additional)
+    }
+
+    // #[inline]
+    // pub fn remove<Q: ?Sized>(&mut self, k: &Q) -> Option<V> {
+    //     // TODO(amunra): May this reallocate memory?
+    //     self.inner.remove(k)
+    // }
+}

src/hash/mod.rs

@@ -0,0 +1 @@
+pub mod map;

src/lib.rs

@@ -10,6 +10,9 @@ pub mod try_clone;
 pub mod vec;
 pub mod vec_deque;
 
+#[cfg(feature = "hash_collections")]
+pub mod hash;
+
 #[cfg(test)]
 pub(crate) mod testing;