factor/vm/bump_allocator.hpp

42 lines
868 B
C++

namespace factor {
template <typename Block> struct bump_allocator {
/* offset of 'here' and 'end' is hardcoded in compiler backends */
cell here;
cell start;
cell end;
cell size;
explicit bump_allocator(cell size_, cell start_)
: here(start_), start(start_), end(start_ + size_), size(size_) {}
bool contains_p(Block* block) { return ((cell) block - start) < size; }
Block* allot(cell size) {
cell h = here;
here = h + align(size, data_alignment);
return (Block*)h;
}
cell occupied_space() { return here - start; }
cell free_space() { return end - here; }
cell next_object_after(cell scan) {
cell size = ((Block*)scan)->size();
if (scan + size < here)
return scan + size;
else
return 0;
}
cell first_object() {
if (start != here)
return start;
else
return 0;
}
};
}