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/*
* Copyright 2017 Google Inc. All Rights Reserved.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#ifndef NB_BIDIRECTIONAL_FIT_REUSE_ALLOCATOR_H_
#define NB_BIDIRECTIONAL_FIT_REUSE_ALLOCATOR_H_
#include "nb/reuse_allocator_base.h"
#include "starboard/configuration.h"
namespace nb {
// This class uses first-fit allocation strategy to allocate memory block whose
// size is greater than the |small_allocation_threshold|. It uses last-fit
// strategy to allocate memory block whose size is less than or equal to the
// |small_allocation_threshold|. This allows better fragmentation management.
// If fragmentation is not an issue, FirstFitReuseAllocator might be a simpler
// alternative.
// Note that when using this class a significant |initial_capacity| should be
// set as otherwise new allocations will almost always allocate from the front
// of the fallback allocator.
class BidirectionalFitReuseAllocator : public ReuseAllocatorBase {
public:
BidirectionalFitReuseAllocator(Allocator* fallback_allocator,
std::size_t initial_capacity,
std::size_t small_allocation_threshold,
std::size_t allocation_increment = 0,
std::size_t max_capacity = 0);
FreeBlockSet::iterator FindFreeBlock(std::size_t size,
std::size_t alignment,
FreeBlockSet::iterator begin,
FreeBlockSet::iterator end,
bool* allocate_from_front) override;
private:
std::size_t small_allocation_threshold_;
};
} // namespace nb
#endif // NB_BIDIRECTIONAL_FIT_REUSE_ALLOCATOR_H_