kstd: ring_buffer: implement [c]end()

2 files changed, 134 insertions, 1 deletions

diff --git a/libs/kstd/kstd/ring_buffer.hpp b/libs/kstd/kstd/ring_buffer.hpp
index a848f3ce..92605fc2 100644
--- a/libs/kstd/kstd/ring_buffer.hpp
+++ b/libs/kstd/kstd/ring_buffer.hpp
@@ -278,6 +278,24 @@ namespace kstd
       return const_iterator{this, 0};
     }
 
+    //! Get an iterator to one past the last element.
+    [[nodiscard]] constexpr auto end() noexcept -> std::default_sentinel_t
+    {
+      return std::default_sentinel;
+    }
+
+    //! Get an iterator to one past the last element.
+    [[nodiscard]] constexpr auto end() const noexcept -> std::default_sentinel_t
+    {
+      return std::default_sentinel;
+    }
+
+    //! Get an iterator to one past the last element.
+    [[nodiscard]] constexpr auto cend() const noexcept -> std::default_sentinel_t
+    {
+      return std::default_sentinel;
+    }
+
     //! @}
 
     //! @name Capacity
diff --git a/libs/kstd/kstd/ring_buffer.tests.cpp b/libs/kstd/kstd/ring_buffer.tests.cpp
index a3881aa6..7a9c56be 100644
--- a/libs/kstd/kstd/ring_buffer.tests.cpp
+++ b/libs/kstd/kstd/ring_buffer.tests.cpp
@@ -121,6 +121,21 @@ SCENARIO("Ring Buffer interface types", "[kstd][ring_buffer]")
     {
       STATIC_REQUIRE(std::is_same_v<buffer::const_iterator, decltype(std::declval<buffer &>().cbegin())>);
     }
+
+    THEN("the return type of end() is `std::default_sentinel_t`")
+    {
+      STATIC_REQUIRE(std::is_same_v<std::default_sentinel_t, decltype(std::declval<buffer &>().end())>);
+    }
+
+    THEN("the return type of end() is `std::default_sentinel_t` on a const buffer")
+    {
+      STATIC_REQUIRE(std::is_same_v<std::default_sentinel_t, decltype(std::declval<buffer const &>().end())>);
+    }
+
+    THEN("the return type of cend() is `std::default_sentinel_t`")
+    {
+      STATIC_REQUIRE(std::is_same_v<std::default_sentinel_t, decltype(std::declval<buffer &>().cend())>);
+    }
   }
 }
 
@@ -348,6 +363,26 @@ SCENARIO("Ring Buffer iterators", "[kstd][ring_buffer]")
       REQUIRE(buffer.cbegin() == std::default_sentinel);
     }
 
+    THEN("begin() returns an iterator equal to end()")
+    {
+      REQUIRE(buffer.begin() == buffer.end());
+    }
+
+    THEN("begin() returns an iterator equal to cend()")
+    {
+      REQUIRE(buffer.begin() == buffer.cend());
+    }
+
+    THEN("cbegin() returns an iterator equal to end()")
+    {
+      REQUIRE(buffer.cbegin() == buffer.end());
+    }
+
+    THEN("cbegin() returns an iterator equal to cend()")
+    {
+      REQUIRE(buffer.cbegin() == buffer.cend());
+    }
+
     WHEN("working through a const reference")
     {
       auto const & ref = buffer;
@@ -356,6 +391,11 @@ SCENARIO("Ring Buffer iterators", "[kstd][ring_buffer]")
       {
         REQUIRE(ref.begin() == std::default_sentinel);
       }
+
+      THEN("begin() returns an iterator equal to end()")
+      {
+        REQUIRE(buffer.begin() == buffer.end());
+      }
     }
   }
 
@@ -363,11 +403,21 @@ SCENARIO("Ring Buffer iterators", "[kstd][ring_buffer]")
   {
     auto buffer = kstd::ring_buffer<char, 5>{3, 'a'};
 
-    THEN("begin() return an iterator that does not equal std::default_sentinel")
+    THEN("begin() returns an iterator that does not equal std::default_sentinel")
     {
       REQUIRE(buffer.begin() != std::default_sentinel);
     }
 
+    THEN("begin() returns an iterator that does not equal end()")
+    {
+      REQUIRE(buffer.begin() != buffer.end());
+    }
+
+    THEN("begin() returns an iterator that does not equal cend()")
+    {
+      REQUIRE(buffer.begin() != buffer.cend());
+    }
+
     THEN("begin() returns an iterator to the first element")
     {
       REQUIRE(*buffer.begin() == 'a');
@@ -378,6 +428,16 @@ SCENARIO("Ring Buffer iterators", "[kstd][ring_buffer]")
       REQUIRE(buffer.cbegin() != std::default_sentinel);
     }
 
+    THEN("cbegin() returns an iterator that does not equal end()")
+    {
+      REQUIRE(buffer.cbegin() != buffer.end());
+    }
+
+    THEN("cbegin() returns an iterator that does not equal cend()")
+    {
+      REQUIRE(buffer.cbegin() != buffer.cend());
+    }
+
     THEN("cbegin() returns an iterator to the first element")
     {
       REQUIRE(*buffer.cbegin() == 'a');
@@ -394,6 +454,26 @@ SCENARIO("Ring Buffer iterators", "[kstd][ring_buffer]")
       REQUIRE(it == std::default_sentinel);
     }
 
+    THEN("incrementing the iterator returned by begin() past the end, yields an iterator equal to end()")
+    {
+      auto it = buffer.begin();
+      ++it;
+      ++it;
+      ++it;
+
+      REQUIRE(it == buffer.end());
+    }
+
+    THEN("incrementing the iterator returned by begin() past the end, yields an iterator equal to cend()")
+    {
+      auto it = buffer.begin();
+      ++it;
+      ++it;
+      ++it;
+
+      REQUIRE(it == buffer.cend());
+    }
+
     THEN("incrementing the iterator returned by cbegin() past the end, yields an iterator equal to "
          "std::default_sentinel")
     {
@@ -405,6 +485,26 @@ SCENARIO("Ring Buffer iterators", "[kstd][ring_buffer]")
       REQUIRE(it == std::default_sentinel);
     }
 
+    THEN("incrementing the iterator returned by cbegin() past the end, yields an iterator equal to end()")
+    {
+      auto it = buffer.cbegin();
+      ++it;
+      ++it;
+      ++it;
+
+      REQUIRE(it == buffer.end());
+    }
+
+    THEN("incrementing the iterator returned by cbegin() past the end, yields an iterator equal to cend()")
+    {
+      auto it = buffer.cbegin();
+      ++it;
+      ++it;
+      ++it;
+
+      REQUIRE(it == buffer.cend());
+    }
+
     WHEN("working through a const reference")
     {
       auto const & ref = buffer;
@@ -414,6 +514,11 @@ SCENARIO("Ring Buffer iterators", "[kstd][ring_buffer]")
         REQUIRE(ref.begin() != std::default_sentinel);
       }
 
+      THEN("begin() return an iterator that does not equal end()")
+      {
+        REQUIRE(ref.begin() != ref.end());
+      }
+
       THEN("begin() returns an iterator to the first element")
       {
         REQUIRE(*ref.begin() == 'a');
@@ -429,6 +534,16 @@ SCENARIO("Ring Buffer iterators", "[kstd][ring_buffer]")
 
         REQUIRE(it == std::default_sentinel);
       }
+
+      THEN("incrementing the iterator returned by begin() past the end, yields an iterator equal to end()")
+      {
+        auto it = ref.begin();
+        ++it;
+        ++it;
+        ++it;
+
+        REQUIRE(it == ref.end());
+      }
     }
   }
 }