From 433f70939c3ecc10702ab6502e3f9bcd94dab739 Mon Sep 17 00:00:00 2001
From: "Tobin C. Harding" <me@tobin.cc>
Date: Thu, 28 Nov 2024 15:56:07 +1100
Subject: [PATCH] Implement iter::Sum for BlockInterval

We support adding two intervals; no obvious reason not to support
summing an iterator of intervals.
---
 units/src/block.rs | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/units/src/block.rs b/units/src/block.rs
index 7b407e33cf..aabb4c2ccb 100644
--- a/units/src/block.rs
+++ b/units/src/block.rs
@@ -231,6 +231,23 @@ impl ops::SubAssign<BlockInterval> for BlockInterval {
     fn sub_assign(&mut self, rhs: BlockInterval) { self.0 = self.to_u32() - rhs.to_u32(); }
 }
 
+impl core::iter::Sum for BlockInterval {
+    fn sum<I: Iterator<Item = Self>>(iter: I) -> Self {
+        let sum = iter.map(|interval| interval.0).sum();
+        BlockInterval::from_u32(sum)
+    }
+}
+
+impl<'a> core::iter::Sum<&'a BlockInterval> for BlockInterval {
+    fn sum<I>(iter: I) -> Self
+    where
+        I: Iterator<Item = &'a BlockInterval>,
+    {
+        let sum = iter.map(|interval| interval.0).sum();
+        BlockInterval::from_u32(sum)
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;