bool FixedAllocator::MakeNewChunk( void )
{
bool allocated = false;
try
{
std::size_t size = chunks_.size();
// Calling chunks_.reserve *before* creating and initializing the new
// Chunk means that nothing is leaked by this function in case an
// exception is thrown from reserve.
if ( chunks_.capacity() == size )
{
if ( 0 == size ) size = 4;
chunks_.reserve( size * 2 );
}
Chunk newChunk;
allocated = newChunk.Init( blockSize_, numBlocks_ );
if ( allocated )
chunks_.push_back( newChunk );
}
catch ( ... )
{
allocated = false;
}
if ( !allocated ) return false;
allocChunk_ = &chunks_.back();
deallocChunk_ = &chunks_.front();
return true;
}
void * FixedAllocator::Allocate()
{
if (!last_alloc_ || last_alloc_->blocks_available_ == 0)
{
// no memory available in the cached chunk, try to find one.
Chunks::iterator e = chunks_.end();
Chunks::iterator i = chunks_.begin();
for (; i!=e; ++i)
{
if (i->blocks_available_ > 0)
{
// found a chunk!
last_alloc_ = &*i;
break;
}
}
if (i == e)
{
// no chunks have blocks available, add a new one.
chunks_.reserve(chunks_.size()+1);
MemChunk chunk;
chunk.Init(block_size_, blocks_);
chunks_.push_back(chunk);
last_alloc_ = &chunks_.back();
last_dealloc_ = &chunks_.back();
}
}
// chunk pointer vaild check
assert(last_alloc_ != NULL);
assert(last_alloc_->blocks_available_ > 0);
return last_alloc_->Allocate(block_size_);
}
void
allocateChunk ()
{
chunks.push_back (new Chunk); // requires c++17 new with alignment
for (Storage& storage : chunks.back ())
{
FreeListNode *node = reinterpret_cast<FreeListNode*> (&storage);
new (node) FreeListNode;
freeList.push_front (*node);
}
}
char* allocate(size_t size)
{
assert(size <= chunk_size);
if (chunks.empty() ||
(next_free + size) > chunk_size)
{
char* chunk = new char[chunk_size];
chunks.push_back(chunk);
next_free = 0;
}
char* ptr = chunks.back() + next_free;
next_free += size;
return ptr;
}