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                 cell size = header & ~7;
  19                 FACTOR_ASSERT(size > 0);
  20                 return size;
  21         }
  22
  23         void make_free(cell size)
  24         {
  25                 FACTOR_ASSERT(size > 0);
  26                 header = size | 1;
  27         }
  28 };
  29
  30 struct block_size_compare {
  31         bool operator()(free_heap_block *a, free_heap_block *b) const
  32         {
  33                 return a->size() < b->size();
  34         }
  35 };
  36
  37 typedef std::multiset<free_heap_block *, block_size_compare> large_block_set;
  38
  39 struct free_list {
  40         std::vector<free_heap_block *> small_blocks[free_list_count];
  41         large_block_set large_blocks;
  42         cell free_block_count;
  43         cell free_space;
  44
  45         void clear_free_list();
  46         void initial_free_list(cell start, cell end, cell occupied);
  47         void add_to_free_list(free_heap_block *block);
  48         free_heap_block *find_free_block(cell size);
  49         free_heap_block *split_free_block(free_heap_block *block, cell size);
  50         bool can_allot_p(cell size);
  51         cell largest_free_block();
  52 };
  53
  54 }