vm/free_list.hpp

   1 namespace factor
   2 {
   3
   4 static const cell free_list_count = 32;
   5 static const cell allocation_page_size = 1024;
   6
   7 struct free_heap_block
   8 {
   9         cell header;
  10
  11         bool free_p() const
  12         {
  13                 return (header & 1) == 1;
  14         }
  15
  16         cell size() const
  17         {
  18                 return header & ~7;
  19         }
  20
  21         void make_free(cell size)
  22         {
  23                 header = size | 1;
  24         }
  25 };
  26
  27 struct block_size_compare {
  28         bool operator()(free_heap_block *a, free_heap_block *b)
  29         {
  30                 return a->size() < b->size();
  31         }
  32 };
  33
  34 typedef std::multiset<free_heap_block *, block_size_compare> large_block_set;
  35
  36 struct free_list {
  37         std::vector<free_heap_block *> small_blocks[free_list_count];
  38         large_block_set large_blocks;
  39         cell free_block_count;
  40         cell free_space;
  41
  42         void clear_free_list();
  43         void initial_free_list(cell start, cell end, cell occupied);
  44         void add_to_free_list(free_heap_block *block);
  45         free_heap_block *find_free_block(cell size);
  46         free_heap_block *split_free_block(free_heap_block *block, cell size);
  47         bool can_allot_p(cell size);
  48         cell largest_free_block();
  49 };
  50
  51 }