factor/vm/free_list.cpp

131 lines
2.6 KiB
C++

#include "master.hpp"
namespace factor
{
void free_list::clear_free_list()
{
for(cell i = 0; i < free_list_count; i++)
small_blocks[i].clear();
large_blocks.clear();
free_block_count = 0;
free_space = 0;
}
void free_list::initial_free_list(cell start, cell end, cell occupied)
{
clear_free_list();
if(occupied != end - start)
{
free_heap_block *last_block = (free_heap_block *)(start + occupied);
last_block->make_free(end - (cell)last_block);
add_to_free_list(last_block);
}
}
void free_list::add_to_free_list(free_heap_block *block)
{
cell size = block->size();
free_block_count++;
free_space += size;
if(size < free_list_count * block_granularity)
small_blocks[size / block_granularity].push_back(block);
else
large_blocks.insert(block);
}
free_heap_block *free_list::find_free_block(cell size)
{
/* Check small free lists */
for(cell i = size / block_granularity; i < free_list_count; i++)
{
std::vector<free_heap_block *> &blocks = small_blocks[i];
if(blocks.size())
{
free_heap_block *block = blocks.back();
blocks.pop_back();
free_block_count--;
free_space -= block->size();
return block;
}
}
/* Check large free lists */
free_heap_block key;
key.make_free(size);
large_block_set::iterator iter = large_blocks.lower_bound(&key);
large_block_set::iterator end = large_blocks.end();
if(iter != end)
{
free_heap_block *block = *iter;
large_blocks.erase(iter);
free_block_count--;
free_space -= block->size();
return block;
}
return NULL;
}
free_heap_block *free_list::split_free_block(free_heap_block *block, cell size)
{
if(block->size() != size)
{
/* split the block in two */
free_heap_block *split = (free_heap_block *)((cell)block + size);
split->make_free(block->size() - size);
block->make_free(size);
add_to_free_list(split);
}
return block;
}
bool free_list::can_allot_p(cell size)
{
/* Check small free lists */
for(cell i = size / block_granularity; i < free_list_count; i++)
{
if(small_blocks[i].size()) return true;
}
/* Check large free lists */
large_block_set::const_iterator iter = large_blocks.begin();
large_block_set::const_iterator end = large_blocks.end();
for(; iter != end; iter++)
{
if((*iter)->size() >= size) return true;
}
return false;
}
cell free_list::largest_free_block()
{
if(large_blocks.size())
{
large_block_set::reverse_iterator last = large_blocks.rbegin();
return (*last)->size();
}
else
{
for(int i = free_list_count - 1; i >= 0; i--)
{
if(small_blocks[i].size())
return small_blocks[i].back()->size();
}
return 0;
}
}
}