kapi/memory: implement multi-frame allocation

2 files changed, 31 insertions, 2 deletions

diff --git a/kapi/include/kapi/memory.hpp b/kapi/include/kapi/memory.hpp
index da666da..c2e9df8 100644
--- a/kapi/include/kapi/memory.hpp
+++ b/kapi/include/kapi/memory.hpp
@@ -10,6 +10,7 @@
 
 #include <cstddef>
 #include <optional>
+#include <utility>
 
 namespace teachos::memory
 {
@@ -46,6 +47,14 @@ namespace teachos::memory
   auto allocate_frame() -> std::optional<frame>;
 
   //! @qualifier kernel-defined
+  //! Allocate multiple new frames of physical memory
+  //!
+  //! @warning This function will panic if no frame allocator has been registered.
+  //!
+  //! @return An engaged std::optional iff. @p count frames could be allocated, std::nullopt otherwise.
+  auto allocate_many_frames(std::size_t count) -> std::optional<std::pair<frame, std::size_t>>;
+
+  //! @qualifier kernel-defined
   //! Map a page onto a frame.
   //!
   //! @warning This function will panic if no page mapper has been registered, or the page has already been mapped.
diff --git a/kapi/include/kapi/memory/frame_allocator.hpp b/kapi/include/kapi/memory/frame_allocator.hpp
index fb6bc0d..8532a45 100644
--- a/kapi/include/kapi/memory/frame_allocator.hpp
+++ b/kapi/include/kapi/memory/frame_allocator.hpp
@@ -5,7 +5,9 @@
 
 #include "kapi/memory/frame.hpp"
 
+#include <cstddef>
 #include <optional>
+#include <utility>
 
 namespace teachos::memory
 {
@@ -27,12 +29,30 @@ namespace teachos::memory
     //! Allocate a frame of physical memory.
     //!
     //! @return An engaged std::optional iff. a new frame could be allocated, std::nullopt otherwise.
-    virtual auto allocate() noexcept -> std::optional<frame> = 0;
+    virtual auto allocate() noexcept -> std::optional<frame>
+    {
+      return allocate_many(1).transform([](auto result) { return result.first; });
+    }
+
+    //! Allocate multiple consecutive frames of physical memory.
+    //!
+    //! @param count The number of frames to allocate
+    //! @return an engaged optional iff. a block of consecutive frames could be allocated, std::nullopt otherwise.
+    virtual auto allocate_many(std::size_t count) noexcept -> std::optional<std::pair<frame, std::size_t>> = 0;
 
     //! Release a frame of physical memory.
     //!
     //! @param frame A frame of physical memory, previously acquired by a call to the #allocate function.
-    virtual auto release(frame frame) -> void = 0;
+    virtual auto release(frame frame) -> void
+    {
+      return release_many({frame, 1});
+    }
+
+    //! Release a frame of physical memory.
+    //!
+    //! @param frame_set A set of frames of physical memory, previously acquired by a call to the #allocate_many
+    //! function.
+    virtual auto release_many(std::pair<frame, std::size_t> frame_set) -> void = 0;
 
   protected:
     frame_allocator() = default;