From f41df033945ae768f224fa478083dd83ce7991ba Mon Sep 17 00:00:00 2001
From: Maneren <49210777+Maneren@users.noreply.github.com>
Date: Sat, 3 Feb 2024 20:23:06 +0100
Subject: [PATCH] Add FromIterator impl

---
 src/default_hashmap.rs | 44 ++++++++++++++++++++++++++++++++++++++++++
 tests/test_hashmap.rs  | 10 ++++++++++
 2 files changed, 54 insertions(+)

diff --git a/src/default_hashmap.rs b/src/default_hashmap.rs
index e5e0116..6a7cba0 100644
--- a/src/default_hashmap.rs
+++ b/src/default_hashmap.rs
@@ -651,6 +651,50 @@ where
     }
 }
 
+impl<K, V, S> Iterator for DefaultHashMapIter<K, V, S>
+where
+    K: Eq + Hash,
+    V: Default,
+    S: BuildHasher,
+{
+    type Item = (K, V);
+
+    fn next(&mut self) -> Option<Self::Item> {
+        match self.keys.pop() {
+            Some(key) => {
+                let val = self._defaulthashmap.remove(&key);
+                Option::Some((key, val))
+            }
+            None => Option::None,
+        }
+    }
+}
+
+pub struct DefaultHashMapIter<K, V, S>
+where
+    K: Eq + Hash,
+    V: Default,
+    S: BuildHasher,
+{
+    _defaulthashmap: DefaultHashMap<K, V, S>,
+    keys: Vec<K>,
+}
+
+impl<K, V, S> FromIterator<(K, V)> for DefaultHashMap<K, V, S>
+where
+    K: Eq + Hash,
+    V: Default,
+    S: BuildHasher + Default,
+{
+    fn from_iter<T: IntoIterator<Item = (K, V)>>(iter: T) -> Self {
+        let mut map = DefaultHashMap::with_hasher(Default::default());
+        for (k, v) in iter {
+            let _ = map.insert(k, v);
+        }
+        map
+    }
+}
+
 #[macro_export]
 /// A quick way to instantiate a HashMap.
 ///
diff --git a/tests/test_hashmap.rs b/tests/test_hashmap.rs
index c40910b..4379605 100644
--- a/tests/test_hashmap.rs
+++ b/tests/test_hashmap.rs
@@ -362,6 +362,16 @@ fn into_iter_default_hashmap() {
     assert_eq!(v, correct_v);
 }
 
+#[test]
+fn from_iter_hashmap() {
+    let data = [(1, 1), (2, 2), (3, 3), (4, 4)];
+    let map: DefaultHashMap<i8, u8> = data.iter().cloned().collect();
+
+    let correct_map: DefaultHashMap<i8, u8> = defaulthashmap!((1, 1), (2, 2), (3, 3), (4, 4));
+
+    assert_eq!(map, correct_map);
+}
+
 #[test]
 fn borrow_loop_over_default_hashmap() {
     let mut map: DefaultHashMap<i8, u8> = DefaultHashMap::new();