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#include <kernel/heapmgr.H>
#include <util/singleton.H>
#include <kernel/console.H>
#include <kernel/pagemgr.H>
void HeapManager::init()
{
Singleton<HeapManager>::instance();
}
void* HeapManager::allocate(size_t n)
{
HeapManager& hmgr = Singleton<HeapManager>::instance();
return hmgr._allocate(n);
}
void HeapManager::free(void* p)
{
HeapManager& hmgr = Singleton<HeapManager>::instance();
return hmgr._free(p);
}
void* HeapManager::_allocate(size_t n)
{
size_t which_bucket = 0;
while (n > (size_t)((1 << (which_bucket + 4)) - 8)) which_bucket++;
chunk_t* chunk = (chunk_t*)NULL;
chunk = pop_bucket(which_bucket);
if (NULL == chunk)
{
newPage();
return _allocate(n);
}
else
{
return &chunk->next;
}
}
void HeapManager::_free(void* p)
{
if (NULL == p) return;
chunk_t* chunk = (chunk_t*)(((size_t*)p)-1);
push_bucket(chunk, chunk->len);
}
HeapManager::chunk_t* HeapManager::pop_bucket(size_t n)
{
if (n >= BUCKETS) return NULL;
chunk_t* c = first_chunk[n].pop();
if (NULL == c)
{
// Couldn't allocate from the correct size bucket, so split up an
// item from the next sized bucket.
c = pop_bucket(n+1);
if (NULL != c)
{
chunk_t* c1 = (chunk_t*)(((uint8_t*)c) + (1 << (n + 4)));
c->len = n;
c1->len = n;
push_bucket(c1, n);
}
}
return c;
}
void HeapManager::push_bucket(chunk_t* c, size_t n)
{
if (n >= BUCKETS) return;
first_chunk[n].push(c);
}
void HeapManager::newPage()
{
void* page = PageManager::allocatePage();
chunk_t * c = (chunk_t*)page;
for (int i = 0; i < (PageManager::PAGESIZE / (1 << (BUCKETS + 3))); i++)
{
c->len = BUCKETS-1;
push_bucket(c, BUCKETS-1);
c = (chunk_t*)(((uint8_t*)c) + (1 << (BUCKETS + 3)));
}
}
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