kstd: ring_buffer: add n-value-initialized ctor

2 files changed, 52 insertions, 0 deletions

diff --git a/libs/kstd/kstd/ring_buffer.hpp b/libs/kstd/kstd/ring_buffer.hpp
index 44510e3e..3e85baae 100644
--- a/libs/kstd/kstd/ring_buffer.hpp
+++ b/libs/kstd/kstd/ring_buffer.hpp
@@ -31,7 +31,24 @@ namespace kstd
     //! Construct an empty ring buffer.
     constexpr ring_buffer() noexcept = default;
 
+    //! Construct a ring buffer with a given number of value initialized elements.
+    //!
+    //! @param count The number of value initialized elements to construct.
+    constexpr ring_buffer(size_type count)
+    {
+      if (count > capacity())
+      {
+        os::panic("[KSTD] Tried to construct a ring buffer with more elements than it can support.");
+      }
+
+      std::ranges::for_each(std::views::iota(0uz, count), [&](auto i) { m_storage.construct(i); });
+      m_write_index = count % capacity();
+    }
+
     //! Construct a ring buffer with a given number of copies of a given value.
+    //!
+    //! @param count The number of copies to construct.
+    //! @param value The value to copy.
     constexpr ring_buffer(size_type count, ValueType const & value)
     {
       if (count > capacity())
diff --git a/libs/kstd/kstd/ring_buffer.tests.cpp b/libs/kstd/kstd/ring_buffer.tests.cpp
index 2157b6c3..43ddafae 100644
--- a/libs/kstd/kstd/ring_buffer.tests.cpp
+++ b/libs/kstd/kstd/ring_buffer.tests.cpp
@@ -152,6 +152,41 @@ SCENARIO("Ring Buffer initialization and construction", "[kstd][ring_buffer]")
       }
     }
   }
+
+  WHEN("constructing by n-value-initialized constructor using a capacity of 5")
+  {
+    auto buffer = kstd::ring_buffer<int, 5>{3};
+
+    THEN("the capacity is 5")
+    {
+      REQUIRE(buffer.capacity() == 5);
+    }
+
+    THEN("the buffer is not empty")
+    {
+      REQUIRE_FALSE(buffer.empty());
+    }
+
+    THEN("the size is equal to the number of copies")
+    {
+      REQUIRE(buffer.size() == 3);
+    }
+
+    THEN("the maximum size is equal to the capacity")
+    {
+      REQUIRE(buffer.max_size() == buffer.capacity());
+    }
+  }
+
+  WHEN("constructing by n-value-initialized constructor using a capacity of 5 and 6 copies")
+  {
+    THEN("the constructor panics")
+    {
+      REQUIRE_THROWS_MATCHES(
+          (kstd::ring_buffer<int, 5>{6}), kstd::tests::os_panic,
+          Catch::Matchers::Message("[KSTD] Tried to construct a ring buffer with more elements than it can support."));
+    }
+  }
 }
 
 SCENARIO("Ring Buffer element access", "[kstd][ring_buffer]")