:github_url: https://github.com/nyx-org/gaia


.. _program_listing_file_lib_freelist.hpp:

Program Listing for File freelist.hpp
=====================================

|exhale_lsh| :ref:`Return to documentation for file <file_lib_freelist.hpp>` (``lib/freelist.hpp``)

.. |exhale_lsh| unicode:: U+021B0 .. UPWARDS ARROW WITH TIP LEFTWARDS

.. code-block:: cpp

   /* SPDX-License-Identifier: BSD-2-Clause */
   #pragma once
   #include <cstdint>
   #include <lib/error.hpp>
   #include <lib/result.hpp>
   
   namespace Gaia {
   
   class Freelist {
   public:
     struct Region {
       size_t size;  
       Region *next; 
     };
   
     explicit Freelist(size_t quantum) : quantum(quantum) {}
     Freelist() : quantum(1) {}
   
     void set_quantum(size_t new_quantum) { quantum = new_quantum; }
   
     void add_region(Region *region) {
       region->next = head;
       head = region;
     }
   
     Result<uintptr_t, Error> alloc() {
       if (!head) {
         return Err(Error::OUT_OF_MEMORY);
       }
   
       auto region = head;
       region->size -= quantum;
   
       if (!head->size) {
         head = head->next;
       }
   
       return Ok((uintptr_t)region + region->size);
     }
   
     void free(uintptr_t mem) {
       auto region = reinterpret_cast<Region *>(mem);
       region->size = quantum;
       add_region(region);
     }
   
   private:
     Region *head = nullptr;
     size_t quantum = 0;
   };
   
   } // namespace Gaia