chromium/third_party/dawn/src/dawn/native/BuddyAllocator.h

// Copyright 2019 The Dawn & Tint Authors
//
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// modification, are permitted provided that the following conditions are met:
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#ifndef SRC_DAWN_NATIVE_BUDDYALLOCATOR_H_
#define SRC_DAWN_NATIVE_BUDDYALLOCATOR_H_

#include <cstddef>
#include <cstdint>
#include <limits>
#include <vector>

#include "partition_alloc/pointers/raw_ptr.h"

namespace dawn::native {

// Buddy allocator uses the buddy memory allocation technique to satisfy an allocation request.
// Memory is split into halves until just large enough to fit to the request. This
// requires the allocation size to be a power-of-two value. The allocator "allocates" a block by
// returning the starting offset whose size is guaranteed to be greater than or equal to the
// allocation size. To deallocate, the same offset is used to find the corresponding block.
//
// Internally, it manages a free list to track free blocks in a full binary tree.
// Every index in the free list corresponds to a level in the tree. That level also determines
// the size of the block to be used to satisfy the request. The first level (index=0) represents
// the root whose size is also called the max block size.
//
class BuddyAllocator { … };

}  // namespace dawn::native

#endif  // SRC_DAWN_NATIVE_BUDDYALLOCATOR_H_