From d8b4ae2ddffa7ff9613d7a6416f3a405d81dad43 Mon Sep 17 00:00:00 2001
From: Felix Morgner <felix.morgner@ost.ch>
Date: Wed, 30 Sep 2026 15:35:29 +0200
Subject: kstd: ring_buffer: implement empty()

---
 libs/kstd/kstd/ring_buffer.hpp       | 13 +++++++++++++
 libs/kstd/kstd/ring_buffer.tests.cpp |  5 +++++
 2 files changed, 18 insertions(+)

(limited to 'libs')

diff --git a/libs/kstd/kstd/ring_buffer.hpp b/libs/kstd/kstd/ring_buffer.hpp
index 2949988e..a25e37b7 100644
--- a/libs/kstd/kstd/ring_buffer.hpp
+++ b/libs/kstd/kstd/ring_buffer.hpp
@@ -26,6 +26,14 @@ namespace kstd
       return Capacity;
     }
 
+    //! Check if this ring buffer is empty.
+    //!
+    //! @return @p true iff. this ring buffer is empty, @p false otherwise.
+    [[nodiscard]] constexpr auto empty() const noexcept -> bool
+    {
+      return m_head == m_tail;
+    }
+
     //! Get the maximum number of elements this ring buffer can hold.
     //!
     //! Due to ring_buffer being a fixed-size container, this function will return the same value as capacity. This
@@ -39,6 +47,11 @@ namespace kstd
 
     //! @}
 
+  private:
+    //! The index of the element that was most recently added to this ring buffer.
+    size_type m_head{};
+    //! The index of the element that was least recently added to this ring buffer.
+    size_type m_tail{};
   };
 
 }  // namespace kstd
diff --git a/libs/kstd/kstd/ring_buffer.tests.cpp b/libs/kstd/kstd/ring_buffer.tests.cpp
index f693b0a8..37243014 100644
--- a/libs/kstd/kstd/ring_buffer.tests.cpp
+++ b/libs/kstd/kstd/ring_buffer.tests.cpp
@@ -15,6 +15,11 @@ SCENARIO("Ring Buffer initialization and construction", "[ring_buffer]")
         REQUIRE(buffer.capacity() == 5);
       }
 
+      THEN("the buffer is empty")
+      {
+        REQUIRE(buffer.empty());
+      }
+
       THEN("the maximum size is equal to the capacity")
       {
         REQUIRE(buffer.max_size() == buffer.capacity());
-- 
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