factor/vm/free_list.hpp

55 lines
1.0 KiB
C++
Executable File

namespace factor
{
static const cell free_list_count = 32;
static const cell allocation_page_size = 1024;
struct free_heap_block
{
cell header;
bool free_p() const
{
return (header & 1) == 1;
}
cell size() const
{
cell size = header & ~7;
FACTOR_ASSERT(size > 0);
return size;
}
void make_free(cell size)
{
FACTOR_ASSERT(size > 0);
header = size | 1;
}
};
struct block_size_compare {
bool operator()(free_heap_block *a, free_heap_block *b) const
{
return a->size() < b->size();
}
};
typedef std::multiset<free_heap_block *, block_size_compare> large_block_set;
struct free_list {
std::vector<free_heap_block *> small_blocks[free_list_count];
large_block_set large_blocks;
cell free_block_count;
cell free_space;
void clear_free_list();
void initial_free_list(cell start, cell end, cell occupied);
void add_to_free_list(free_heap_block *block);
free_heap_block *find_free_block(cell size);
free_heap_block *split_free_block(free_heap_block *block, cell size);
bool can_allot_p(cell size);
cell largest_free_block();
};
}