From 78d8b5f73c309ab16ae1941ba5c949a74ccbc2fd Mon Sep 17 00:00:00 2001
From: Max Kellermann <max.kellermann@gmail.com>
Date: Thu, 10 Nov 2022 15:57:51 +0100
Subject: [PATCH] util/OptionalCounter: add operator+= and operator-=

---
 src/util/OptionalCounter.hxx | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/src/util/OptionalCounter.hxx b/src/util/OptionalCounter.hxx
index ad4a43988..f00e846b3 100644
--- a/src/util/OptionalCounter.hxx
+++ b/src/util/OptionalCounter.hxx
@@ -44,6 +44,8 @@ public:
 	constexpr void reset() noexcept {}
 	constexpr auto &operator++() noexcept { return *this; }
 	constexpr auto &operator--() noexcept { return *this; }
+	constexpr auto &operator+=(std::size_t) noexcept { return *this; }
+	constexpr auto &operator-=(std::size_t) noexcept { return *this; }
 };
 
 template<>
@@ -71,4 +73,16 @@ public:
 		--value;
 		return *this;
 	}
+
+	constexpr auto &operator+=(std::size_t n) noexcept {
+		value += n;
+		return *this;
+	}
+
+	constexpr auto &operator-=(std::size_t n) noexcept {
+		assert(value >= n);
+
+		value -= n;
+		return *this;
+	}
 };