single_chunk_region_tracker.h

// Copyright 2025 The Pigweed Authors
//
// 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
//
//     https://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.
#pragma once
 
#include <atomic>
#include <cstddef>
#include <optional>
 
#include "pw_allocator/allocator.h"
#include "pw_allocator/block/tiny_block.h"
#include "pw_allocator/first_fit.h"
#include "pw_allocator/layout.h"
#include "pw_bytes/span.h"
#include "pw_containers/storage.h"
#include "pw_multibuf/v1_adapter/chunk.h"
#include "pw_multibuf/v1_adapter/internal/chunk_allocator.h"
#include "pw_multibuf/v2/internal/entry.h"
 
namespace pw::multibuf::v1_adapter {
 
 
class SingleChunkRegionTracker : private internal::SingleChunkAllocator {
 private:
  using Base = internal::SingleChunkAllocator;
 
 public:
  SingleChunkRegionTracker()
      : Base(metadata_allocator_), metadata_allocator_(metadata_buffer_) {}
 
  explicit SingleChunkRegionTracker(ByteSpan region)
      : SingleChunkRegionTracker() {
    SetRegion(region);
  }
 
  using Base::Destroy;
  using Base::SetRegion;
 
  ByteSpan Region() const { return Base::buffer(); }
 
  std::optional<OwnedChunk> GetChunk(size_t size) {
    return Base::AllocateChunk(size);
  }
 
 private:
  static constexpr size_t kBufSize = sizeof(v2::internal::Entry) * 32;
 
  std::array<std::byte, kBufSize> metadata_buffer_{};
 
  allocator::FirstFitAllocator<allocator::TinyBlock> metadata_allocator_;
};
 
 
}  // namespace pw::multibuf::v1_adapter