vm/bump_allocator.hpp

   1 namespace factor
   2 {
   3
   4 template<typename Block> struct bump_allocator {
   5         /* offset of 'here' and 'end' is hardcoded in compiler backends */
   6         cell here;
   7         cell start;
   8         cell end;
   9         cell size;
  10
  11         explicit bump_allocator(cell size_, cell start_) :
  12                 here(start_), start(start_), end(start_ + size_), size(size_) {}
  13
  14         bool contains_p(Block *block)
  15         {
  16                 return ((cell)block - start) < size;
  17         }
  18
  19         Block *allot(cell size)
  20         {
  21                 cell h = here;
  22                 here = h + align(size,data_alignment);
  23                 return (Block *)h;
  24         }
  25
  26         cell occupied_space()
  27         {
  28                 return here - start;
  29         }
  30
  31         cell free_space()
  32         {
  33                 return end - here;
  34         }
  35
  36         cell next_object_after(cell scan)
  37         {
  38                 cell size = ((Block *)scan)->size();
  39                 if(scan + size < here)
  40                         return scan + size;
  41                 else
  42                         return 0;
  43         }
  44
  45         cell first_object()
  46         {
  47                 if(start != here)
  48                         return start;
  49                 else
  50                         return 0;
  51         }
  52 };
  53
  54 }