kapi/memory: extract common base of page and frame

4 files changed, 134 insertions, 129 deletions

diff --git a/kapi/include/kapi/memory.hpp b/kapi/include/kapi/memory.hpp
index 2f45611..bed8dbc 100644
--- a/kapi/include/kapi/memory.hpp
+++ b/kapi/include/kapi/memory.hpp
@@ -2,6 +2,7 @@
 #define TEACHOS_KAPI_MEMORY_HPP
 
 #include "kapi/memory/address.hpp"          // IWYU pragma: export
+#include "kapi/memory/chunk.hpp"            // IWYU pragma: export
 #include "kapi/memory/frame.hpp"            // IWYU pragma: export
 #include "kapi/memory/frame_allocator.hpp"  // IWYU pragma: export
 #include "kapi/memory/page.hpp"             // IWYU pragma: export
diff --git a/kapi/include/kapi/memory/chunk.hpp b/kapi/include/kapi/memory/chunk.hpp
new file mode 100644
index 0000000..fde2e36
--- /dev/null
+++ b/kapi/include/kapi/memory/chunk.hpp
@@ -0,0 +1,104 @@
+#ifndef TEACHOS_KAPI_MEMORY_CHUNK_HPP
+#define TEACHOS_KAPI_MEMORY_CHUNK_HPP
+
+// IWYU pragma: private, include "kapi/memory.hpp"
+
+#include <compare>
+#include <cstddef>
+
+namespace teachos::memory
+{
+
+  //! @qualifier kernel-defined
+  //! A fixed-size unit of memory, indexed by a number.
+  //!
+  //! @tparam AddressType The type of addresses used to index this chunk
+  //! @tparam Size The size of this chunk.
+  template<typename AddressType, std::size_t Size>
+  struct chunk
+  {
+    //! The type of addresses used to index this chunk
+    using address_type = AddressType;
+
+    //! The size of this chunk
+    constexpr auto static size = Size;
+
+    //! Construct a handle referencing the first chunk of the respective address space.
+    constexpr chunk() noexcept = default;
+
+    //! Construct a handle referencing the chunk of memory with the given number.
+    explicit constexpr chunk(std::size_t number) noexcept
+        : m_number{number}
+    {}
+
+    //! Construct a new chunk handle for the chunk containing the given address.
+    //!
+    //! @param address An address contained by the desired chunk.
+    //! @return A handle to a chunk containing the given address.
+    constexpr auto static containing(address_type address) noexcept -> chunk
+    {
+      return chunk{address.raw() / size};
+    }
+
+    //! Get the start address of the chunk referenced by this handle.
+    //!
+    //! @return The address of the first byte contained by the chunk referenced by this handle.
+    [[nodiscard]] constexpr auto start_address() const noexcept -> address_type
+    {
+      return address_type{m_number * size};
+    }
+
+    //! Get the number of the chunk referenced by this handle.
+    //!
+    //! @return The zero-based number of the chunk referenced by this handle.
+    [[nodiscard]] constexpr auto number() const noexcept -> std::size_t
+    {
+      return m_number;
+    }
+
+    //! Get a handle n chunks after the one referenced by this handle.
+    //!
+    //! @param n The positive offset to this chunk.
+    //! @return A handle referencing the chunk n chunks after the one referenced by this handle.
+    constexpr auto operator+(std::size_t n) const noexcept -> chunk
+    {
+      return chunk{m_number + n};
+    }
+
+    //! Let this handle reference the next chunk after the currently reference one.
+    //!
+    //! @return A handle referencing the same chunk as this handle did before the operation.
+    constexpr auto operator++(int) noexcept -> chunk
+    {
+      auto copy = *this;
+      ++*this;
+      return copy;
+    }
+
+    //! Let this handle reference the next chunk after the currently reference one.
+    //!
+    //! @return A reference to this handle.
+    constexpr auto operator++() noexcept -> chunk &
+    {
+      ++m_number;
+      return *this;
+    }
+
+    //! Check if this chunk handle reference the same chunk as another one.
+    //!
+    //! @param other Another chunk handle.
+    constexpr auto operator==(chunk const & other) const noexcept -> bool = default;
+
+    //! Compare the number of the chunk referenced by this handle to the one reference by another one.
+    //!
+    //! @param other Another chunk handle.
+    constexpr auto operator<=>(chunk const & other) const noexcept -> std::strong_ordering = default;
+
+  private:
+    //! The number of the currently referenced chunk.
+    std::size_t m_number{};
+  };
+
+}  // namespace teachos::memory
+
+#endif
\ No newline at end of file
diff --git a/kapi/include/kapi/memory/frame.hpp b/kapi/include/kapi/memory/frame.hpp
index c8bcb92..49f3bb0 100644
--- a/kapi/include/kapi/memory/frame.hpp
+++ b/kapi/include/kapi/memory/frame.hpp
@@ -4,93 +4,34 @@
 // IWYU pragma: private, include "kapi/memory.hpp"
 
 #include "kapi/memory/address.hpp"
-
-#include <compare>
-#include <cstddef>
+#include "kapi/memory/chunk.hpp"
 
 namespace teachos::memory
 {
 
+  //! @qualifier kernel-defined
   //! A handle to a frame of physical memory.
-  struct frame
+  //!
+  //! @note Contrary to the address types, this type is modeled using inheritance to support future extensions.
+  struct frame : chunk<physical_address, PLATFORM_FRAME_SIZE>
   {
-    //! The platform-dependent size of a single frame of memory.
-    constexpr auto static size = PLATFORM_FRAME_SIZE;
-
-    //! Construct a handle referencing the first frame of physical memory.
-    constexpr frame() noexcept = default;
-
-    //! Construct a handle referencing the frame of memory with the given frame number.
-    explicit constexpr frame(std::size_t number) noexcept
-        : m_number{number}
-    {}
+    using chunk::chunk;
 
-    //! Construct a new frame handle for the frame containing the given address.
+    //! @copydoc chunk::containing
     //!
-    //! @param address A physical address contained by the desired frame.
-    //! @return A handle to a frame containing the given address.
+    //! @note This factory shadows the base factory to aid in type deduction.
     constexpr auto static containing(physical_address address) noexcept -> frame
     {
-      return frame{address.raw() / size};
-    }
-
-    //! Get the start address of the frame referenced by this handle.
-    //!
-    //! @return The address of the first byte contained by the frame referenced by this handle.
-    [[nodiscard]] constexpr auto start_address() const noexcept -> physical_address
-    {
-      return physical_address{m_number * size};
-    }
-
-    //! Get the number of the frame referenced by this handle.
-    //!
-    //! @return The zero-based number of the frame referenced by this handle.
-    [[nodiscard]] constexpr auto number() const noexcept -> std::size_t
-    {
-      return m_number;
-    }
-
-    //! Get a handle n frames after the one referenced by this handle.
-    //!
-    //! @param n The positive offset to this frame.
-    //! @return A handle referencing the frame n frames after the one referenced by this handle.
-    constexpr auto operator+(std::size_t n) const noexcept -> frame
-    {
-      return frame{m_number + n};
-    }
-
-    //! Let this handle reference the next frame after the currently reference one.
-    //!
-    //! @return A handle referencing the same frame as this handle did before the operation.
-    constexpr auto operator++(int) noexcept -> frame
-    {
-      auto copy = *this;
-      ++*this;
-      return copy;
-    }
-
-    //! Let this handle reference the next frame after the currently reference one.
-    //!
-    //! @return A reference to this handle.
-    constexpr auto operator++() noexcept -> frame &
-    {
-      ++m_number;
-      return *this;
+      return frame{chunk::containing(address)};
     }
 
-    //! Check if this frame handle reference the same frame as another one.
+    //! Convert a base chunk into a page.
     //!
-    //! @param other Another frame handle.
-    constexpr auto operator==(frame const & other) const noexcept -> bool = default;
-
-    //! Compare the number of the frame referenced by this handle to the one reference by another one.
-    //!
-    //! @param other Another frame handle.
-    constexpr auto operator<=>(frame const & other) const noexcept -> std::strong_ordering = default;
-
-  private:
-    //! The number of the currently referenced frame.
-    std::size_t m_number{};
+    //! This constructor allows for conversion from chunk<physical_address, PLATFORM_FRAME_SIZE> to a frame for
+    //! convenience. It is deliberately not explicit.
+    constexpr frame(chunk other)
+        : chunk{other}
+    {}
   };
 
 }  // namespace teachos::memory
diff --git a/kapi/include/kapi/memory/page.hpp b/kapi/include/kapi/memory/page.hpp
index 0b7083a..57f4f09 100644
--- a/kapi/include/kapi/memory/page.hpp
+++ b/kapi/include/kapi/memory/page.hpp
@@ -4,75 +4,34 @@
 // IWYU pragma: private, include "kapi/memory.hpp"
 
 #include "kapi/memory/address.hpp"
-
-#include <compare>
-#include <cstddef>
+#include "kapi/memory/chunk.hpp"
 
 namespace teachos::memory
 {
 
   //! @qualifier kernel-defined
   //! A handle to a page of virtual memory.
-  struct page
+  //!
+  //! @note Contrary to the address types, this type is modeled using inheritance to support future extensions.
+  struct page : chunk<linear_address, PLATFORM_PAGE_SIZE>
   {
-    //! The platform-dependent size of a single page of memory.
-    constexpr auto static size = PLATFORM_FRAME_SIZE;
-
-    //! Construct a handle referencing the first page of virtual memory.
-    constexpr page() = default;
+    using chunk::chunk;
 
-    //! Construct a handle referencing the page of virtual memory with the given page number.
-    explicit constexpr page(std::size_t number)
-        : m_number{number}
-    {}
-
-    //! Construct a new page handle for the page containing the given address.
+    //! @copydoc chunk::containing
     //!
-    //! @param address A linear address contained by the desired page.
-    //! @return A handle to a page containing the given address.
+    //! @note This factory shadows the base factory to aid in type deduction.
     constexpr auto static containing(linear_address address) noexcept -> page
     {
-      return page{address.raw() / size};
-    }
-
-    //! Get the start address of the page referenced by this handle.
-    //!
-    //! @return The address of the first byte contained by the page referenced by this handle.
-    [[nodiscard]] constexpr auto start_address() const noexcept -> linear_address
-    {
-      return linear_address{m_number * size};
-    }
-
-    //! Get the number of the page referenced by this handle.
-    //!
-    //! @return The zero-based number of the page referenced by this handle.
-    [[nodiscard]] constexpr auto number() const noexcept -> std::size_t
-    {
-      return m_number;
-    }
-
-    //! Get a handle n pages after the one referenced by this handle.
-    //!
-    //! @param n The positive offset to this page.
-    //! @return A handle referencing the page n pages after the one referenced by this handle.
-    constexpr auto operator+(std::size_t n) const noexcept -> page
-    {
-      return page{m_number + n};
+      return page{chunk::containing(address)};
     }
 
-    //! Check if this page handle reference the same frame as another one.
-    //!
-    //! @param other Another page handle.
-    constexpr auto operator==(page const & other) const noexcept -> bool = default;
-
-    //! Compare the number of the page referenced by this handle to the one reference by another one.
+    //! Convert a base chunk into a page.
     //!
-    //! @param other Another page handle.
-    constexpr auto operator<=>(page const & other) const noexcept -> std::strong_ordering = default;
-
-  private:
-    //! The number of the currently referenced page.
-    std::size_t m_number{};
+    //! This constructor allows for conversion from chunk<linear_address, PLATFORM_PAGE_SIZE> to a page for convenience.
+    //! It is deliberately not explicit.
+    constexpr page(chunk other)
+        : chunk{other}
+    {}
   };
 
 }  // namespace teachos::memory