fragmentation.h

// Copyright 2024 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 <cstddef>
 
namespace pw::allocator {
 
 
// inclusive-language: disable
 
struct Fragmentation {
  // inclusive-language: enable
 
  struct {
    size_t hi = 0;
    size_t lo = 0;
  } sum_of_squares;
 
  size_t sum = 0;
 
  void AddFragment(size_t inner_size);
 
  void SubtractFragment(size_t inner_size);
 
  Fragmentation& operator+=(const Fragmentation& other);
 
  Fragmentation& operator-=(const Fragmentation& other);
 
  constexpr bool operator==(const Fragmentation& other) const {
    return sum == other.sum && sum_of_squares.hi == other.sum_of_squares.hi &&
           sum_of_squares.lo == other.sum_of_squares.lo;
  }
 
  constexpr bool operator!=(const Fragmentation& other) const {
    return !(*this == other);
  }
 
  friend Fragmentation operator+(const Fragmentation& lhs,
                                 const Fragmentation& rhs) {
    Fragmentation result = lhs;
    result += rhs;
    return result;
  }
 
  friend Fragmentation operator-(const Fragmentation& lhs,
                                 const Fragmentation& rhs) {
    Fragmentation result = lhs;
    result -= rhs;
    return result;
  }
};
 
float CalculateFragmentation(const Fragmentation& fragmentation);
 
 
}  // namespace pw::allocator