Start with linked list alloc and dealloc

2 files changed, 57 insertions, 0 deletions

diff --git a/arch/x86_64/include/arch/memory/heap/linked_list_allocator.hpp b/arch/x86_64/include/arch/memory/heap/linked_list_allocator.hpp
index a742018..da7fc37 100644
--- a/arch/x86_64/include/arch/memory/heap/linked_list_allocator.hpp
+++ b/arch/x86_64/include/arch/memory/heap/linked_list_allocator.hpp
@@ -22,12 +22,42 @@ namespace teachos::arch::memory::heap
     linked_list_allocator(std::size_t heap_start, std::size_t heap_end);
 
     /**
+     * @brief Allocates the specified amount of memory in the heap.
+     *
+     * @param size Amount of memory to allocate.
+     * @return Address of the first byte to the allocated area
+     */
+    auto allocate(std::size_t size) -> void *;
+
+    /**
+     * @brief Deallocates heap memory at the specified location.
+     *
+     * @note Simply does nothing, because this allocator leaks all memory.
+     *
+     * @param pointer Pointer to the location which should be deallocated.
+     * @param size Size of the underlying memory area we want to deallocate.
+     */
+    auto deallocate(uint8_t * pointer, std::size_t size) -> void;
+
+  private:
+    /**
      * @brief Returns the smallest allocatable block of heap memory.
      *
      * @return Smallest allocatable block of heap memory.
      */
     auto constexpr min_allocatable_size() -> std::size_t { return sizeof(memory_hole); }
 
+    /**
+     * @brief Splits the given hole into two, where the latter block keeps beeing free and the first part will be used
+     * for the allocation.
+     *
+     * @param current_hole Hole we want to split.
+     * @param new_hole New hole created by the split.
+     *
+     * @return Address of the hole we just split.
+     */
+    auto split_hole(memory_hole & current_hole, memory_hole *& new_hole) -> void *;
+
     std::size_t heap_start;  ///< Start of the allocatable heap area
     std::size_t heap_end;    ///< End of the allocatable heap area
     memory_hole first;       ///< First free entry in our memory
diff --git a/arch/x86_64/src/memory/heap/linked_list_allocator.cpp b/arch/x86_64/src/memory/heap/linked_list_allocator.cpp
index b0f011b..006d9c7 100644
--- a/arch/x86_64/src/memory/heap/linked_list_allocator.cpp
+++ b/arch/x86_64/src/memory/heap/linked_list_allocator.cpp
@@ -2,6 +2,8 @@
 
 #include "arch/exception_handling/assert.hpp"
 
+#include <algorithm>
+
 namespace teachos::arch::memory::heap
 {
   linked_list_allocator::linked_list_allocator(std::size_t heap_start, std::size_t heap_end)
@@ -13,4 +15,29 @@ namespace teachos::arch::memory::heap
                                "[Memory Hole List] Total heap size can not be smaller than minimum of 16 bytes to hold "
                                "atleast one memory hole entry");
   }
+
+  auto linked_list_allocator::allocate(std::size_t size) -> void *
+  {
+    if (first.next == nullptr || size)
+    {
+    }
+    return nullptr;
+  }
+
+  auto linked_list_allocator::deallocate(uint8_t * pointer, std::size_t size) -> void
+  {
+    auto const deallocate_size = std::max(size, min_allocatable_size());
+    if (pointer || deallocate_size)
+    {
+    }
+  }
+
+  auto split_hole(memory_hole & current_hole, memory_hole *& new_hole) -> void *
+  {
+    if (new_hole)
+    {
+    }
+    return static_cast<void *>(&current_hole);
+  }
+
 }  // namespace teachos::arch::memory::heap