From 43c39a3ec08dd9d0e519b5effce26625020ca085 Mon Sep 17 00:00:00 2001
From: Matej Focko <me@mfocko.xyz>
Date: Thu, 6 Jul 2023 19:08:53 +0200
Subject: [PATCH] lib: implement column iterator

Signed-off-by: Matej Focko <me@mfocko.xyz>
---
 src/iterators/column_iterator.rs | 25 +++++++++++++++++++++++++
 src/iterators/mod.rs             |  2 ++
 src/lib.rs                       |  3 +++
 3 files changed, 30 insertions(+)
 create mode 100644 src/iterators/column_iterator.rs
 create mode 100644 src/iterators/mod.rs

diff --git a/src/iterators/column_iterator.rs b/src/iterators/column_iterator.rs
new file mode 100644
index 0000000..119d8fe
--- /dev/null
+++ b/src/iterators/column_iterator.rs
@@ -0,0 +1,25 @@
+pub struct ColumnIterator<'a, T> {
+    map: &'a [Vec<T>],
+    column: usize,
+
+    i: usize,
+}
+
+impl<'a, T> ColumnIterator<'a, T> {
+    pub fn new(map: &'a [Vec<T>], column: usize) -> ColumnIterator<'a, T> {
+        Self { map, column, i: 0 }
+    }
+}
+
+impl<'a, T> Iterator for ColumnIterator<'a, T> {
+    type Item = &'a T;
+
+    fn next(&mut self) -> Option<Self::Item> {
+        if self.i >= self.map.len() {
+            return None;
+        }
+
+        self.i += 1;
+        Some(&self.map[self.i - 1][self.column])
+    }
+}
diff --git a/src/iterators/mod.rs b/src/iterators/mod.rs
new file mode 100644
index 0000000..c28d744
--- /dev/null
+++ b/src/iterators/mod.rs
@@ -0,0 +1,2 @@
+mod column_iterator;
+pub use column_iterator::*;
diff --git a/src/lib.rs b/src/lib.rs
index 0286b60..d962d55 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -10,5 +10,8 @@ pub use testing::*;
 mod vectors;
 pub use vectors::*;
 
+mod iterators;
+pub use iterators::*;
+
 mod data_structures;
 pub use data_structures::*;