From eb6e713c1dd0a500441a837ded154b763d2e0353 Mon Sep 17 00:00:00 2001
From: Avril <flanchan@cumallover.me>
Date: Tue, 17 Nov 2020 22:03:28 +0000
Subject: [PATCH] added reverse

---
 Cargo.toml   |  2 +-
 src/lib.rs   | 14 ++++++++++++++
 src/tests.rs | 20 ++++++++++++++++++++
 3 files changed, 35 insertions(+), 1 deletion(-)

diff --git a/Cargo.toml b/Cargo.toml
index d517228..63aea1c 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -4,7 +4,7 @@ description = "Small byte-sized generic key-value map type"
 keywords = ["map", "table", "small", "key", "value"]
 repository = "https://github.com/notflan/smallmap"
 homepage= "https://git.flanchan.moe/flanchan/smallmap"
-version = "1.1.6"
+version = "1.2.0"
 authors = ["Avril <flanchan@cumallover.me>"]
 edition = "2018"
 license = "MIT"
diff --git a/src/lib.rs b/src/lib.rs
index 9dc9014..472814d 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -389,6 +389,20 @@ where K: Collapse
 	self.0.push(page);
 	None
     }
+    
+    /// Consume this `Map` by swapping its keys and values around.
+    pub fn reverse(self) -> Map<V,K>
+    where V: Collapse
+    {
+	let mut output = Map::with_capacity(self.num_pages());
+
+	for (k,v) in self.into_iter()
+	{
+	    output.insert(v, k);
+	}
+
+	output
+    }
 }
 
 impl<K: Collapse, V> IntoIterator for Map<K,V>
diff --git a/src/tests.rs b/src/tests.rs
index b5022ce..6b438e6 100644
--- a/src/tests.rs
+++ b/src/tests.rs
@@ -101,6 +101,26 @@ fn type_primitive()
     test_insert_type!(i128, 0..10000);
 }
 
+#[test]
+fn reverse()
+{
+    let map = smallmap![
+	{"one" => 1},
+	{"two" => 2},
+	{"three" => 3},
+	{"four" => 4},
+    ];
+    let expected = smallmap![
+	{1 => "one"},
+	{2 => "two"},
+	{3 => "three"},
+	{4 => "four"},
+    ];
+
+    assert_eq!(map.reverse(), expected);
+    assert_eq!(expected.reverse().into_iter().map(|(_, v)| v).sum::<i32>(), 4+3+2+1);
+}
+
 #[cfg(nightly)]
 mod benchmarks
 {