add values()

rinde · Dec 15, 2023 · 56d1095 · 56d1095
1 parent 9502b14
commit 56d1095
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Showing 3 changed files with 107 additions and 12 deletions.
diff --git a/doc/vec_map.md b/doc/vec_map.md
@@ -19,7 +19,7 @@ Below is an overview of the all methods and traits that are implemented for `Vec
 | `iter_mut()`             | ✅                            |
 | `keys()`                 | ✅                            |
 | `into_keys()`            |                              |
-| `values()`               | planned                      |
+| `values()`               | ✅                            |
 | `values_mut()`           |                              |
 | `into_values()`          |                              |
 | `clear()`                | ✅                            |
@@ -118,12 +118,12 @@ Below is an overview of the all methods and traits that are implemented for `Vec
 | --------------------- | ----------- | ----------- | ----------- | ----------- | ----------- | ----------- | ----------- | ----------- | ------------ |
 | `as_slice()`          | not planned | not planned | not planned | not planned | not planned | not planned | not planned | not planned | not planned  |
 | `as_mut_slice()`      | not planned | not planned | not planned | not planned | not planned | not planned | not planned | not planned | not planned  |
-| `Iterator`            | ✅           | ✅           | ✅           |             | ✅           |             | planned     |             |              |
-| `DoubleEndedIterator` | ✅           | ✅           | ✅           |             | ✅           |             | planned     |             |              |
-| `ExactSizeIterator`   | ✅           | ✅           | ✅           |             | ✅           |             | planned     |             |              |
-| `FusedIterator`       | ✅           | ✅           | ✅           |             | ✅           |             | planned     |             |              |
-| `Clone`               | ✅           |             | ✅           |             | ✅           |             |             |             |              |
-| `Debug`               | ✅           | ✅           | ✅           |             | ✅           |             |             |             |              |
+| `Iterator`            | ✅           | ✅           | ✅           |             | ✅           |             | ✅           |             |              |
+| `DoubleEndedIterator` | ✅           | ✅           | ✅           |             | ✅           |             | ✅           |             |              |
+| `ExactSizeIterator`   | ✅           | ✅           | ✅           |             | ✅           |             | ✅           |             |              |
+| `FusedIterator`       | ✅           | ✅           | ✅           |             | ✅           |             | ✅           |             |              |
+| `Clone`               | ✅           |             | ✅           |             | ✅           |             | ✅           |             |              |
+| `Debug`               | ✅           | ✅           | ✅           |             | ✅           |             | ✅           |             |              |
 
 ## Serde support
 

diff --git a/src/vec_map/iter.rs b/src/vec_map/iter.rs
@@ -265,6 +265,65 @@ where
     }
 }
 
+/// An iterator over the values following the key natural order.
+#[derive(Clone)]
+pub struct Values<'a, V> {
+    pub(super) inner: core::slice::Iter<'a, Option<V>>,
+    pub(super) len: usize,
+}
+
+impl<'a, V> Iterator for Values<'a, V> {
+    type Item = &'a V;
+
+    fn next(&mut self) -> Option<Self::Item> {
+        if self.len == 0 {
+            return None;
+        }
+        self.inner.find_map(|value| value.as_ref()).map(|v| {
+            self.len -= 1;
+            v
+        })
+    }
+}
+
+impl<'a, V> DoubleEndedIterator for Values<'a, V> {
+    fn next_back(&mut self) -> Option<Self::Item> {
+        if self.len == 0 {
+            return None;
+        }
+        self.inner
+            .by_ref()
+            .rev()
+            .find_map(|value| value.as_ref())
+            .map(|v| {
+                self.len -= 1;
+                v
+            })
+    }
+}
+
+impl<'a, V> ExactSizeIterator for Values<'a, V> {
+    fn len(&self) -> usize {
+        self.len
+    }
+}
+
+impl<'a, V> FusedIterator for Values<'a, V> {}
+
+impl<'a, V> fmt::Debug for Values<'a, V>
+where
+    V: fmt::Debug,
+{
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        // TODO why can't we use self.clone()
+        let iter: Values<'a, V> = Values {
+            inner: self.inner.clone(),
+            len: self.len,
+        };
+        f.debug_list().entries(iter).finish()
+    }
+}
+
 #[cfg(test)]
 mod test {
     use crate::vecmap;
@@ -408,4 +467,37 @@ mod test {
         assert_eq!(None, iter.next());
         assert_eq!(0, iter.len());
     }
+
+    #[test]
+    fn test_values() {
+        let map = vecmap! { 9u16 => "nine", 17 => "seventeen", 2 => "two"};
+
+        // forward
+        let mut iter = map.values();
+        assert_eq!(3, iter.len());
+        assert_eq!(Some(&"two"), iter.next());
+        assert_eq!(2, iter.len());
+        assert_eq!(Some(&"nine"), iter.next());
+        assert_eq!(1, iter.len());
+        assert_eq!(Some(&"seventeen"), iter.next());
+        assert_eq!(0, iter.len());
+        assert_eq!(None, iter.next());
+
+        // back, forward, back
+        let mut iter = map.values();
+        assert_eq!(3, iter.len());
+        assert_eq!(Some(&"seventeen"), iter.next_back());
+        assert_eq!(2, iter.len());
+        assert_eq!(Some(&"two"), iter.next());
+        assert_eq!(1, iter.len());
+        assert_eq!(Some(&"nine"), iter.next_back());
+        assert_eq!(0, iter.len());
+        assert_eq!(None, iter.next_back());
+
+        let map: VecMap<usize, usize> = VecMap::with_capacity(40);
+        let mut iter = map.values();
+        assert_eq!(0, iter.len());
+        assert_eq!(None, iter.next());
+        assert_eq!(0, iter.len());
+    }
 }
diff --git a/src/vec_map/mod.rs b/src/vec_map/mod.rs
@@ -7,10 +7,7 @@ use std::marker::PhantomData;
 use std::ops::Index;
 use std::ops::IndexMut;
 
-pub use crate::vec_map::iter::IntoIter;
-pub use crate::vec_map::iter::Iter;
-use crate::vec_map::iter::IterMut;
-pub use crate::vec_map::iter::Keys;
+pub use crate::vec_map::iter::*;
 
 /// A key that can be used in a map without needing a hasher.
 ///
@@ -242,7 +239,13 @@ impl<K: IndexKey, V> VecMap<K, V> {
         }
     }
 
-    // TODO values()
+    /// Returns an iterator over the values of the map following the natural order of the keys.
+    pub fn values(&self) -> Values<'_, V> {
+        Values {
+            inner: self.data.iter(),
+            len: self.len,
+        }
+    }
 }
 
 impl<K: IndexKey, V> Default for VecMap<K, V> {