kstd: ring_buffer: implement size()

2 files changed, 18 insertions, 0 deletions

diff --git a/libs/kstd/kstd/ring_buffer.hpp b/libs/kstd/kstd/ring_buffer.hpp
index a25e37b7..0e54c070 100644
--- a/libs/kstd/kstd/ring_buffer.hpp
+++ b/libs/kstd/kstd/ring_buffer.hpp
@@ -34,6 +34,19 @@ namespace kstd
       return m_head == m_tail;
     }
 
+    //! Get the size of this ring buffer.
+    //!
+    //! @return The number of elements currently stored in this ring buffer.
+    [[nodiscard]] constexpr auto size() const noexcept -> size_type
+    {
+      if (m_head >= m_tail)
+      {
+        return m_head - m_tail;
+      }
+
+      return capacity() - m_tail + m_head;
+    }
+
     //! 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
diff --git a/libs/kstd/kstd/ring_buffer.tests.cpp b/libs/kstd/kstd/ring_buffer.tests.cpp
index 37243014..6e936248 100644
--- a/libs/kstd/kstd/ring_buffer.tests.cpp
+++ b/libs/kstd/kstd/ring_buffer.tests.cpp
@@ -20,6 +20,11 @@ SCENARIO("Ring Buffer initialization and construction", "[ring_buffer]")
         REQUIRE(buffer.empty());
       }
 
+      THEN("the size is 0")
+      {
+        REQUIRE(buffer.size() == 0);
+      }
+
       THEN("the maximum size is equal to the capacity")
       {
         REQUIRE(buffer.max_size() == buffer.capacity());